Critical Factors in the Biology of Human Cancer Metastasis: Twenty-Eighth G

Home , Cancer research, Metastasis

(CANCER RESEARCH 50. 6130-6138, October l, 1990] Special Lecture Critical Factors in the Biology of Human Cancer Metastasis: Twenty-eighth G. H. A. Clowes Memorial Award Lecture1

Isaiah J. Fidler Department of Cell Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030

Abstract Kerbel, Philip Frost, Michael Hanna, David Tarin, and Fred erick Becker for productive collaboration and warm friendship. The process of metastasis is not random. Rather, it consists of a series I also take this opportunity to thank the National Cancer of linked, sequential steps that must be completed by tumor cells if a metastasis is to develop. Although some of the steps in this process Institute and other funding sources for providing the necessary contain stochastic elements, as a whole, metastasis favors the survival support without which hypotheses cannot become reality. and growth of a few subpopulations of cells that preexist within the I am extremely pleased that Dr. Henry Mihich introduced parent neoplasm. Moreover, mÃ©tastasescan have a clonal origin, and my presentation. In 1978, when he was the Program Chairman different mÃ©tastasescan originate from the proliferation of single cells. of the Annual Meeting, he introduced me as a speaker on a The outcome of metastasis depends on the interaction of metastatic cells topic of current interest: "Tumor heterogeneity and the biology with different organ environments. Organ-specific mÃ©tastaseshave been of cancer invasion and metastasis." At that time, Garth Nicol demonstrated in a variety of experimental tumor systems. Moreover, we son, George Poste, Gloria Heppner, and I, among others, had have found tumor growth that is specific to a particular site within one just begun to understand these processes, and I remember how organ. Whether the same conclusions can be reached for human cancers remained unanswered until very recently. honored I was to be chosen to describe some of the early findings Studies from our laboratory and from others have shown that the in this emerging field (1). During the last decade, our collective implantation of human cancer cells derived from surgical specimens into knowledge has advanced considerably, and in this presentation correct anatomical sites of nude mice can provide a suitable model of I shall describe some of the progress accomplished by us and metastasis of human tumors. Clonal analysis of a human renal carcinoma, others. colon carcinomas, and melanomas has revealed that these tumors are My lecture is divided into three parts. First, I shall discuss indeed heterogeneous for metastatic properties, an observation made only the pathogenesis of metastasis and describe some of the mech after orthotopic implantation. Thus, growth in the environment of specific anisms that regulate this process. Second, I shall describe the organs can be selective and the environment per se influences this process. While it is clear that vascularity and local immunity can facilitate or development of animal models to study the biology of human retard tumor growth, we have concentrated on understanding how damage cancer metastasis. Finally, I shall describe preliminary data on to an organ and the subsequent repair process can facilitate tumor cell the role of homeostatic factors in the pathogenesis of metasta proliferation. Accelerated growth of human colon cancer cells was found sis. in hepatectomized nude mice, whereas accelerated growth of human renal Metastasis, the spread of cells from the primary neoplasm to cancer cells was found in nephrectomized nude mice. These data suggest distant sites and their growth there, is the most fearsome aspect that systemic physiological signals can be recognized by neoplastic cells of cancer. This fear is well founded. Despite significant im presumably by mechanisms similar to those shared by their normal cell provements in early diagnosis, surgical techniques, general pa counterparts. In summary, the critical factors that regulate metastasis are the intrinsic properties of metastatic cells and host factors involved tient care, and local and systemic adjuvant therapies, most in homeostasis. The recent increase in our understanding of metastasis deaths from cancer are due to mÃ©tastasesthat are resistant to should provide important leads for developing more effective approaches conventional therapies (1-9). In a large number of patients with to the treatment of disseminated cancer. cancer, metastasis may well have occurred by the time of diagnosis (4, 6, 8, 9). The mÃ©tastasescan be located in different Introduction lymph nodes and visceral organs and in various regions of the same organ, thus complicating their treatment. Furthermore, To be a recipient of the G. H. A. Clowes Memorial Award is the specific organ environment can modify the response of a a distinct honor which I shall always cherish. I consider myself metastatic tumor cell to systemic therapy and alter the efficiency a representative of a larger group of scientists whose endeavors of anticancer agents. in elucidating the mysteries of cancer metastasis you have The major barrier to the treatment of mÃ©tastasesis the recognized. During the last 20 years, I have devoted myself to biological heterogeneity of cancer cells in primary and second the understanding of the biology and therapy of cancer metas ary neoplasms. This heterogeneity is exhibited in a wide range tasis. My interest in this field was stimulated by my teacher, of genetic, biochemical, immunologie-ai, and biological charac Irving Zeidman, who taught me to ask relevant questions, to teristics, such as cell surface receptors, enzymes, karyotypes, search for answers, and to even sometimes ignore dogmas. I cell morphologies, growth properties, sensitivities to various am also grateful to many friends, colleagues, and students with therapeutic agents, and ability to invade and produce metastasis whom I have worked. Their contributions will become clear (1-5, 10-15). Moreover, it is important to remember the term during my presentation. In particular, I thank Margaret Kripke, "cancer" denotes a collection of malignancies, with each cancer George Poste, Garth Nicolson, Ian Hart, Avraham Raz, Robert of each organ consisting of numerous subsets. This tremendous Received 6/26/90; accepted 6/27/90. heterogeneity is probably due to the different etiologies, origins, ' Financial support of this research was provided by Grant R35-CA 42107 and selection pressures of different cancers. from the National Cancer Institute. NIH. Presented at the Seventy-ninth Annual Meeting of the American Association for Cancer Research, May 26. 1988, in Continual empiricism in the treatment of cancer is unlikely New Orleans, LA. to produce significant improvement. Therefore understanding 6130

Downloaded from cancerres.aacrjournals.org on September 27, 2021. © 1990 American Association for Cancer Research. CRITICAL FACTORS IN HUMAN CANCER METASTASIS the mechanisms responsible for the development of biological extravasation occurs next, probably by the same mechanisms heterogeneity in primary cancers and in mÃ©tastasesand the that influence initial invasion; (g) proliferation within the organ process by which tumor cells invade local tissues and spread to parenchyma completes the metastatic process. To produce de distant organs is a primary goal of cancer research. Only from tectable lesions, the mÃ©tastasesmust develop a vascular net a better understanding will come the ability to design more work, evade the host immune system (2), and respond to organ- effective therapy for different cancers and improvements in the specific factors that influence their growth (24-28). Once they way physicians deal with cancer metastasis. My lecture, there do so, the cells can invade host stroma, penetrate blood vessels, fore, reviews recent data that provide some answers to these and enter the circulation to produce secondary mÃ©tastases,the so-called "metastasis of mÃ©tastases"(7-9). difficult questions. When I described the metastatic process, 1 emphasized that only a few cells in a primary tumor can give rise to a metastasis. The Pathogenesis of a Metastasis This is due in part to the elimination of any disseminating tumor cell that fails to complete any step in metastasis. The The process of cancer metastasis consists of a long series of complexity of the pathogenesis of metastasis explains, in part, sequential interrelated steps, each of which can be rate limiting why the process is deemed to be inefficient (9, 29). For example, since a failure or an insufficiency at any of the steps aborts the the presence of tumor cells in the circulation does not predict process (7). The outcome of the process is dependent on both that metastasis will occur, because most tumor cells that enter the intrinsic properties of the tumor cells and the responses of the blood stream are rapidly eliminated (30). Using radiolabeled the host; the balance of these interactions can vary among B16 melanoma cells, I observed that by 24 h after entry into different patients (2, 6, 9). In principle, the steps or events the circulation, <1% of the cells are still viable, and <0.1% of required for the formation of a metastasis are the same in all tumor cells placed into the circulation survived to produce tumors, and I therefore illustrate the process by using mela mÃ©tastases(30). Observations such as this prompted me to ask noma as the model (Fig. 1). whether the development of mÃ©tastasesrepresents the fortui Major steps in the formation of a metastasis are as follows: tous survival and growth of very few neoplastic cells or whether (a) after the initial transforming event, either unicellular or it represents the selective growth of unique subpopulations of multicellular, growth of neoplastic cells must be progressive; malignant cells endowed with special properties. In other words, (b) extensive vascularization must occur if a tumor mass is to can all cells growing in a primary neoplasm produce secondary- exceed 2 mm in diameter (16). The synthesis and secretion of lesions, or do only specific and unique cells possess the appro several angiogenesis factors play a key role in establishing a priate properties that would enable them to survive the poten neocapillary network from the surrounding host tissue (17,18); tially destructive journey from the primary tumor to the sites (c) local invasion of the host stroma by some tumor cells could of future mÃ©tastases?Most recent data indeed show that neo occur by several mechanisms that are not mutually exclusive (19-22). Thin-walled venules, like lymphatic channels, offer plasms are biologically heterogeneous and that the process of metastasis is selective. very little resistance to penetration by tumor cells and provide the most common pathways for tumor cell entry into the circulation. Although clinical observations have suggested that Metastatic Heterogeneity carcinomas frequently metastasize and grow via the lymphatic system, whereas malignant tumors of mesenchymal origin, e.g., Cells with different metastatic properties have been isolated melanoma, more often spread by the hematogenous route, the from the same parent tumor, thus supporting the hypothesis presence of numerous venolymphatic anastomoses invalidates that not all the cells in a primary tumor can successfully this belief (23); (Â¡I)detachment and embolization of small disseminate. Two general approaches have been used to isolate tumor cell aggregates occurs next; (e) tumor cells that survive populations of cells that differ from the parent neoplasm in the circulation must arrest in the capillary beds of organs; (/) metastatic capacity. In the first, metastatic cells are selected in vivo: tumor cells are implanted s.c., i.m., or into other tissues, The Metastatic Process or they are injected i.v. into mice, and metastasis is allowed to occur. The metastatic lesions are harvested, and the cells that Primarymalignant Neovascularization Invasion Embolism are recovered can first be expanded in culture or used immedi neoplasm ately to repeat the process. The cycle is repeated several times. The behavior of the cycled cells is compared with that of the Lymphatics, Multiceliaggregates cells of the parent tumor to determine whether the selection Venules.capillaries {Lymphocyte,platelets) process enhanced metastatic capacity (31), and the increase in metastatic capacity of the recovered cells did not result from Responseto the adaptation of tumor cells to preferential growth in a partic microenvironment -~ \^fÂ»j ular organ (32-34). This procedure was originally used to isolate the B16-F10 line from the wild-type B16 melanoma Extravasation Adherence Arrestin distant organcapillarybed (31). It has also been successfully used to produce tumor cell lines with increased metastatic capacity from many of the Metastasisof Tumorcell "^BtBWBP ^ experimental tumors tested (35-39). MÃ©tastases proliferation In the second approach, cells are selected for the enhanced expression of a phenotype believed to be important in one or Metastases another step of the metastatic sequence, and then they are Fig. 1. The pathogenesis of a metastasis. To produce mÃ©tastases,tumor cells tested in the appropriate host to determine whether concomi in a primary neoplasm must complete a series of sequential and selective steps, each of which can be rate limiting since a failure or an insufficiency at any of the tant metastatic potential has been increased or decreased. This steps aborts the process. method has been used to examine whether properties as diverse 6131

Downloaded from cancerres.aacrjournals.org on September 27, 2021. © 1990 American Association for Cancer Research. CRITICAL FACTORS IN HUMAN CANCER METASTASIS as resistance to T-lymphocytes (40,41), adhesive characteristics completion of one or another step in the complex metastatic (42, 43), invasive capacity (36, 44-46), lectin resistance (43, 47, process (Fig. 2). 48), and resistance to natural killer cells (49) are important in The finding that preexisting tumor cell subpopulations pro metastasis. liferating in the same tumor exhibit heterogeneous metastatic One obvious criticism of these studies is that the surviving potential has since been confirmed in many laboratories, with isolated tumor line may have arisen as a result of adaptive a wide range of experimental animal tumors of different histo rather than selective processes. The first experimental proof for ries and histological origins (1-4,7, 10,11, 13-15). In addition, metastatic heterogeneity in neoplasms was provided by Mar studies using young nude mice as models for metastasis of garet Kripke and me in 1977 in work with the mouse B16 human neoplasms have shown that several human tumor lines melanoma (50). Using the modified fluctuation assay of Luria and freshly isolated tumors, such as colon carcinoma and renal and Delbruck (51), we showed that different tumor cell clones, carcinoma, also contain subpopulations of cells with widely each derived from individual cells isolated from the parent differing metastatic properties (60). tumor, vary dramatically in their ability to form pulmonary James Talmadge and I also addressed the question of whether nodules following i.v. inoculation into syngeneic mice. Control the cells that survive to form mÃ©tastasespossess a greater subcloning procedures demonstrated that the observed diversity metastatic capacity than most cells in an unselected neoplasm was not a consequence of the cloning procedure (50). (31, 34, 37). Most lines derived from metastatic deposits pro To exclude the possibility that the metastatic heterogeneity duced significantly more mÃ©tastasesthan cells of the parent found in the B16 melanoma might have been introduced as a line. Studies with heterogeneous, unselected neoplasms have result of the lengthy in vivo and in vitro cultivation, we studied therefore led us to conclude that metastasis is a selective process the biological and metastatic heterogeneity in a mouse mela regulated by a number of different mechanisms. noma induced in C3H mice by chronic exposure to UV B radiation and painting with croton oil (52). One mouse thus Role of the Organ Environment in the Pathogenesis of Metastasis treated developed a melanoma designated K-1735. The original K-1735 melanoma was established in culture and immediately Clinical observations of cancer patients and studies with cloned (53, 54). In an experiment similar in design to the one experimental rodent tumors have revealed that certain tumors described for the B16 melanoma (50), we found that the clones produce metastasis to specific organs independent of vascular differed greatly from each other and from the parent tumor in anatomy, rate of blood flow, and number of tumor cells deliv their ability to produce lung mÃ©tastases.In addition to differ ered to each organ. The distribution and fate of hematogenously ences in the number of mÃ©tastases,we also found significant disseminated, radiolabeled melanoma cells in experimental ro variability in the size and pigmentation of the mÃ©tastases. dent systems amply demonstrate that tumor cells reach the microvasculature of many organs (30, 61-63). Extravasation MÃ©tastasesto the lymph nodes, brain, heart, liver, and skin were found in addition to lung mÃ©tastases;those growing in the into the organ parenchyma and proliferation of tumor cells brain were uniformly melanotic, whereas those growing in other occur in only some organs. Therefore, the mere presence of organs generally were not (27, 53, 54). viable tumor cells in a particular organ does not always predict that the cells will proliferate to produce mÃ©tastases(24-26, 64). To determine whether the absence of metastasis production by some clones of the K-1735 melanoma was a consequence of The search for the mechanisms that regulate the pattern of their immunological rejection by the normal host (55-58), metastasis began a century ago. In 1889, Paget (65) questioned whether the distribution of mÃ©tastaseswas due to chance. He Nabil Hanna and I examined their metastatic behavior in young therefore analyzed 735 autopsy records of women with breast nude mice (59, 60). In such recipients, the immunological cancer. The nonrandom pattern of visceral mÃ©tastasessuggested barrier to metastatic cells that also may be highly immunogenic to Paget that the process was not due to chance but, rather, is removed, and antigenic metastatic cells may thus successfully that certain tumor cells (the "seed") had a specific affinity for complete the process. Cells of two clones that did not produce the milieu of certain organs (the "soil"). MÃ©tastasesresulted mÃ©tastasesin normal syngeneic mice produced tumor foci in only when the seed and soil were matched (65). the young nude mice. However, most of the nonmetastatic Experimental data supporting the "seed and soil" hypothesis clones were nonmetastatic in both normal syngeneic and nude of Paget were derived from studies on the preferential invasion recipients. Therefore, the failure of the clones to metastasize in and growth of B16 melanoma mÃ©tastasesinspecific organs (66, syngeneic mice was probably not caused by their immunological 67). Ian Hart and I injected B16 melanoma cells into the rejection by the host but by other deficiencies that prevented circulation of syngeneic C57BL/6 mice. Tumor growths devel oped in the lungs and in fragments of pulmonary or ovarian tissue implanted i.m. In contrast, metastatic lesions did not BENIGN MALIGNANT develop in renal tissue implanted as a control or at the site of surgical trauma (67). This study confirmed that sites of metas tasis are determined not solely by the characteristics of the neoplastic cells but also by the microenvironment of the host tissue. In vitro experiments demonstrating organ-selective adhe sion, invasion, and growth also support Paget's hypothesis (65). With the B16 melanoma system, cells that are selective for organ adhesion, invasion, and growth have been isolated (24, 26, 31-39, 68). Moreover, experiments with organ tissue-de rived soluble growth factors indicate that soil factors can have Fig. 2. Metastatic and nonmetastatic phenotypes. Failure to produce a metas tasis can be due to a single or to multiple deficiencies. Therefore, not all profound effects on certain tumor cell subpopulations (24). nonmetastatic cells share identical phenotypes. There is no question that the circulatory anatomy influences 6132

Downloaded from cancerres.aacrjournals.org on September 27, 2021. © 1990 American Association for Cancer Research. CRITICAL FACTORS IN HUMAN CANCER METASTASIS the dissemination of many malignant cells (6, 8, 9); however, it still is an urgent need for such a model because the major goal cannot, as Ewing proposed (69), fully explain the patterns of of oncologists is the prevention or eradication of mÃ©tastases, distribution of numerous tumors. Ethical considerations rule and in many patients with colon cancer, metastasis is likely to out the experimental analysis of cancer metastasis in patients have occurred prior to diagnosis and surgical resection of the as studied in laboratory animals, by which either Paget or Ewing primary tumor (74). might be proved correct. The introduction of peritoneovenous Vince Pollack and I have previously shown that nude mice shunts for palliation of malignant ascites has, however, pro can be used to ascertain the metastatic potential of allogeneic vided an opportunity to study some of the factors affecting tumors and that metastatic variants can be selected in nude metastatic spread in humans. David Tarin and colleagues have mice from heterogeneous mouse tumors (75). We therefore described the outcome in patients with malignant ascites drain decided to use similar techniques to investigate the metastatic ing into the venous circulation, with the resulting entry of viable potential of HCC. We reasoned that if a HCC contained met tumor cells into the jugular veins (70, 71 ). Good palliation with astatic cells, these cells would produce metastasis in nude mice, minimal complications was reported for 29 patients with dif whereas HCCs that do not contain metastatic cells will not. As ferent neoplasms. The autopsy findings in 15 patients substan you shall soon see, this was a gross oversimplification. tiated the clinical observations that the shunts do not signifi cantly increase the risk of metastasis. In fact, despite continuous Correlation of Experimental Metastatic Behavior with Clinical entry of millions of tumor cells into the circulation, mÃ©tastases Staging in the lung (the first capillary bed encountered) were rare (70, 71). These results provide compelling verification of the ven In initial studies, four tumor lines were derived from primary erable "seed and soil" hypothesis (65). HCCs, three from hepatic mÃ©tastasesand one from a mesenteric An interesting demonstration for organ-specific metastasis lymph node metastasis. Tumor cells of each line were injected comes from recent studies. Gabriele Schackert and I described into multiple sites in nude mice: the spleen; the subcutis; the development of a mouse model with which to study cerebral muscle; and the venous system (76, 77). All the inoculi consisted metastasis after injection of syngeneic tumor cells into the of single-cell suspensions obtained by enzymatic dissociation of internal carotid artery (72, 73). A direct, i.e.2 injection of tumor solid tumors. In the course of these experiments, we examined cells was used to determine tumorigenicity. The injection of by autopsy approximately 600 mice that had growing HCC. cells into the internal carotid artery of mice simulates the Injection s.c., although successful in initiating local tumor hematogenous spread of tumor emboli to the brain. Thus, this growth in only one case yielded visceral metastasis to the lung. technique can examine the last steps of the metastatic process: In only 10 did histolÃ³gica! examination reveal tumor growth in release of tumor cells into the circulation; arrest of tumor cells lymph nodes draining the injection site (76, 77). in capillaries; penetration and extravasation of the tumor cells MÃ©tastasesof colorectal cancer may occur late in the disease, into the brain through the blood-brain barrier; and continuous often after surgical resection of the primary tumor. In some growth of the cells in the tissue. reports of experimental tumor systems in rodents, multiple We found a remarkable difference between two murine mel mÃ©tastasesdeveloped subsequent to surgical removal of a local anomas in patterns of brain metastasis; the K-1735 melanoma tumor. Similarly, the incidence of lung mÃ©tastaseswas shown produced lesions only in the brain parenchyma, whereas the to increase with the prolonged survival of nude mice that had B16 melanoma produced only meningea! growths (73). These locally recurrent HCC at the site of injection-resection (78). In results demonstrate specificity for metastatic growth in different our experiments with nude mice, we injected HCC cells into a regions within a single organ. The results from site distribution hind thigh and amputated the leg when the tumors reached analysis of radiolabeled murine melanoma cells injected into 1.5-2 cm. Although most of the mice developed recurrent the internal carotid artery ruled out that the patterns of initial tumor at the incision site, mÃ©tastaseswere found in lungs of cell arrest in the microvasculature of the brain predicted the only two mice, even though all mice survived for 6 months after eventual sites of growth. Thus, an alternative explanation for the initial tumor cell injection. Neither cells from primary the different sites of tumor growth involves interactions between HCCs nor cells from mÃ©tastasesproduced metastasis in nude the metastatic cells and the organ environment, possibly in mice subsequent to s.c. or i.m. implantation. When the HCC terms of specific binding to endothelial cells and responses to cells were administered i.V., no correlation was found between local growth factors. In other words, organ-specific mÃ©tastases the experimental lung mÃ©tastasesand the clinical stage of the are produced by tumor cells that are receptive to their new original neoplasms. environment. We next made a critical decision. Hepatic mÃ©tastasesaccount for many of the deaths from colorectal carcinoma. To develop Models for Human Cancer Metastasis a reproducible model of hepatic metastasis, tumor cells have been implanted into the spleens of nude mice. From this site of An appropriate model for studies of human cancer metastasis injection, tumor cells gain access to the blood stream and then must meet two rigid demands: it must use metastatic cells reach the liver to proliferate into secondary tumor colonies. In (seed), and it must grow in the relevant organ environment our laboratory, James Kozlowski and coworkers (79) investi (soil). In 1983, when I joined the faculty of the University of gated the metastatic behavior of 11 human cell lines of different Texas M. D. Anderson Cancer Center, I began a collaborative histolÃ³gica! origin and the production of lung and liver mÃ©tas study with Drs. Kim Jessup, Raffaella Giavazzi, and later tases in the nude mouse. The extent of metastasis depended on Kiyoshi Morikawa to design a bioassay of the malignant poten the nature of the tumor cells, with the most dramatic expression tial of cells from surgical specimens of HCCs. There was and of malignancy found for two variants of the HT-29 HCC cell 2The abbreviations used are: i.e.. intracranial; i.s., intrasplenic: HCC. human line subsequent to i.s. injection (79). Merely implanting human colon carcinoma; CEA. carcinoembryonic antigen: HRCC, human renal cell tumor cells into the spleens of nude mice does not guarantee carcinoma. that metastasis to the liver will occur. A more recent study from 6133

Downloaded from cancerres.aacrjournals.org on September 27, 2021. © 1990 American Association for Cancer Research. CRITICAL FACTORS IN HUMAN CANCER METASTASIS our laboratory demonstrated that variant lines established from every tumor and, therefore, failed in the mission of developing a surgical specimen of a human renal cell carcinoma produced a bioassay to improve prognosis and recommend a course of extensive metastasis if the cells were implanted into the kidney therapy. We did, however, learn a valuable lesson, the principle of nude mice. In contrast, i.s. implantation of these cells pro of orthotopic transplantation. The orthotopic transplantation duced only splenic tumors and not metastasis (80). of colon tumor has been described for a chemically induced The i.s. injection of HCC cells followed by the formation of murine adenocarcinoma (85-87). Colon tumor cells were in tumor lesions in the liver allowed us to distinguish HCC with jected into different sites along the small and large intestines different malignant potentials. Thirty days after the injection of syngeneic mice. The highest rate of tumor take occurred in of tumor cells derived from liver mÃ©tastasesof HCC (Dukes' the cecum, and about 50% of mice with local tumors developed stage D), the mice became moribund and were then killed. At liver mÃ©tastases.The same tumor implanted s.c. grew locally autopsy, their livers were completely replaced by tumor. Mice and produced pulmonary but not hepatic mÃ©tastases(78, 88). given injections of cells from primary colorectal carcinomas Kiyoshi Morikawa and I next began experiments with ortho- developed few visible tumor foci in the liver by 90 days after topic implantations to select and isolate cells with increased i.s. injection. Cells of one primary tumor produced visible liver liver-metastasizing potential from heterogeneous primary tumor in all the injected mice, but this required 90 days (76, HCCs. Cells derived from a surgical specimen of a primary 77). The cells recovered from the liver lesions were of human HCC classified as Dukes' stage B2 were directly established in origin (karyotype and isoenzyme analyses). culture or were injected into the subcutis, cecum, or spleen of The previous studies demonstrated that the i.s. injection of nude mice. Progressively growing tumors were excised, disso HCC cells can lead to the production of discrete tumor nodules ciated, and established in culture. Subsequent to implantation in the liver. To further delineate the malignancy of tumors of into the cecum or spleen of nude mice, cells from all 4 lines different origin, Kiyoshi Morikawa compared the behavior of produced only a few liver tumor foci. HCC cells from the few HCC cells enzymatically dissociated from surgical specimens of a primary HCC classified as Dukes' stage, B2, a primary liver mÃ©tastaseswere expanded in culture and then injected HCC classified as Dukes' stage D, and one liver metastasis. into the spleen of nude mice to provide a source for further cycles of selection. With each successive in vivo selection cycle, The cells were implanted into the subcutis or spleen of different the metastatic ability of the isolated-propagated cells increased. nude mice or were established in culture. Tumors developed in Four cycles of selection yielded cell lines with a very high both sites of implantation, but hepatic tumor nodules were metastatic efficiency in nude mice (81). In parallel studies using found only in mice given injections of HCC cells into the spleen (81, 82). Once again, cells from surgical specimen of Dukes' another surgical specimen of a primary HCC classified as Dukes' stage D, we isolated cell lines that were highly metastatic stage D tumors produced a significantly higher number of HCC colonies in the liver of nude mice than cells from the Dukes' in nude mice. Successive selection cycles for growth in the liver stage B tumor. only slightly increased metastatic properties (81). As I mentioned earlier, we began these studies nearly 5 years The metastatic potential of the HCC cells in nude mice was ago, a sufficient time to be able to determine whether the determined by two different assays. The first involved the production of experimental hepatic mÃ©tastasesinathymic nude implantation of cells into the spleen and the production of liver mice by HCC correlated with the clinical outcome in patients. tumor foci (experimental metastasis). The second assay meas HCC cells from 82 patients were injected into groups of nude ured the ability of HCC cells to produce lymph node and liver mice, either in the flank to assess tumorigenicity or into the mÃ©tastasessubsequent to implantation into the wall of the spleen to produce experimental metastasis in the liver. Growth cecum (spontaneous metastasis). In general, there was agree in mice was recorded and compared with clinicopathological ment on the results of the two assays; a cell line highly met factors and clinical outcome. Growth of HCC in either the astatic to the liver after i.e. injection was also highly metastatic Hanks or the livers of nude mice was associated with the time to the mesenteric lymph nodes after intracecal injection. Nei to recurrence of disease (postsurgery) in a Wilcoxon analysis. ther assay revealed HCC mÃ©tastasesto the lung (81, 82). Analysis of the outcome data in a Cox proportional hazards The nude mouse model had been used to select metastatic model suggested that there was an interaction between tumor cells from heterogeneous nonselected murine neoplasms (75). igenicity and metastatic potential of HCC in nude mice and Our present results confirm these findings and show that the serum carcinoembryonic antigen (CEA) concentration in the nude mouse can be used to isolate and expand metastatic patient and the stage of disease. A univariate analysis indicated subpopulations of cells from HCCs. The classification of a HCC as Dukes' B tumor denotes that the lesion is confined to that both tumorigenicity and metastatic potential of HCC in nude mice were significantly associated with the serum CEA the wall of the colon without any evidence for metastatic disease (74). In contrast, a HCC classified as Dukes' D tumor presents concentration of the patient but not with the other variables such as stage of disease, mucin production, local tissue invasion, with obvious mÃ©tastasesin lymph nodes and visceral organs (74). In general, Dukes' B tumors are likely to be an earlier or state of differentiation. A subset of 57 patients was operated manifestation of HCC than Dukes' D tumors. Clinical obser upon for cure and followed prospectively for up to 61 months. Tumorigenicity in nude mice and experimental metastatic po vations of various neoplasms have suggested that tumors tend tential were associated with disease recurrence in 23 of these to evolve with the passage of time. Neoplasms that are first patients. Seventy-eight % of the subset of patients who were diagnosed as noninvasive-nonmetastatic can progress to be operated upon for cure developed liver metastasis. Collectively, come metastatic (1-4). In the case of HCCs, it is entirely possible that an early Dukes' B neoplasm can progress to the ability of HCC cells isolated from surgical specimens to grow in athymic nude mice correlated with the development of become a Dukes' D neoplasm. If such were the case, Dukes' B advanced disease in patients (83, 84). tumors should contain but few metastatic cells, whereas Dukes' These results, however, were somewhat disappointing be D tumors should contain a large number of metastatic cells. cause we did not succeed in assessing metastatic potential in Our present data support this assumption (81, 82). 6134

Studies with a Human Renal Cell Carcinoma Orthotopic versus Ectopie Implantations for Studies of Sponta neous Metastasis HRCC is not a very common cancer. The prognosis of a patient with this cancer is poor because no effective therapy has The implantation of human tumor cells into the subcutis of been established for advanced stages of this disease. Although nude mice has been reported by many investigators, but the several investigators have reported the successful transplanta growing tumors fail to produce metastasis (20). Therefore, even tion of HRCC cells into the subcutis of nude mice (89-91), the if human tumors growing s.c. in nude mice maintain their usefulness of this model has been limited. Like other tumor original morphological and biochemical characteristics, it is cells, transplanted HRCC cells rarely metastasize in nude mice, questionable whether the s.c. environment of the nude mouse regardless of their degree of malignancy in the patient (60). The is the most appropriate site for the growth of human tumors finding that the growth rate and incidence of cancer metastasis (except skin cancers and melanomas). The ideal in vivo model in nude mice can be increased by manipulation of the route of for studying this disease should allow the interaction of the tumor cell implantation and organ implantation sites (76, 78) tumor cells with their relevant organ environment. prompted Seiji Naito to investigate whether the orthotopic The data I just discussed raised the question of which organ implantation of HRCC into the kidney of nude mice would site of nude mice should be used for the transplantation of allow the expression of malignant potential. heterogeneous human tumors. Although the routine transplan The purpose of the initial study was to determine whether tation of human tumors into the s.c. space of nude mice is the methods for isolating cells from a surgical specimen of a relatively easy, it may not yield cell lines that resemble the HRCC influence the biological behavior of the cancer cells. original human tumor. If a human tumor is biologically heter HRCC obtained from a surgical specimen was dissociated by ogeneous, some of its cells may possess a growth advantage, enzymatic treatment (80, 92), and cells were plated into culture depending on whether it is transplanted to the skin, the cecum, dishes or injected s.c. and into the kidney of nude mice. A the liver, or the kidney of nude mice. Orthotopic implantation in nude mice of human tumor cells resultant kidney tumor also produced liver mÃ©tastasesand recovered from surgical specimens is mandatory for accurate ascites. All tumors growing in different organs of nude mice assessment of metastatic potential. This is the case not only were then established in culture. The human origin of all five with human colon (76, 77, 81, 82, 84, 87, 89, 93, 94) and renal lines was ascertained by karyotypic and isoenzyme analysis. cell carcinomas (80, 92), but also melanomas (into the skin) Because the five cell lines of HRCCs were isolated by five (95-98), mammary carcinomas (into the mammary fat pad) different methods (culture, s.c. tumor, renal tumor, liver metas (99-101), bladder carcinomas (into the bladder wall) (102,103), tasis from the renal tumor, and ascitic cells from the renal prostatic carcinoma (into the peritoneum) (79), pancreatic car tumor), we asked whether the cell lines exhibited biological cinoma (into the pancreas) (104-108), and lung cancer (into heterogeneity, including differences in metastatic potential, and the bronchi) (109). All result in rapid growth of local tumors whether different implantation sites in nude mice would influ and, in many instances, in distant metastasis. ence such behavior. In sharp contrast, the implantation of these very same human Cells from all lines were injected s.c., i.p., i.v., i.s., and cancer cells at ectopie sites (usually s.c. or i.m.) results in slow beneath the renal capsule of nude mice. All the lines were growth of local tumors and only rarely in metastasis. These tumorigenic after s.c. or renal subcapsule injection, although findings are by no means restricted to human neoplasms in the rate of tumor growth varied among the five lines. The nude mice. Similar data show that the implantation site of metastatic behavior of the cells differed significantly among the mouse neoplasms, such as fibrosarcoma (110), melanomas 5 lines. Some cells exhibited invasive and metastatic properties (111), mammary carcinomas (112), and the Lewis lung carci regardless of organ site for their implantation (s.c., i.v., Â¡.p.,or noma (113) greatly influences the biological behavior of the kidney). In contrast, cells of the other lines were poorly met neoplasms. astatic regardless of the site of implantation. Second, the high est incidence of metastasis by the HRCC lines was produced by tumors growing in the kidney. The injection of cells into the Homeostasis and Cancer Metastasis peritoneum, spleen, or subcutis was associated with tumori- For the final (and brief) portion of my presentation, I wish genicity but not metastasis (80). to speculate about a mechanism that may influence the growth The work with HRCC is important for two reasons. First, and behavior of tumor cells at orthotopic sites. During my the site of implantation of human tumor cells can promote the lecture, I have emphasized that the outcome of metastasis is growth of different subpopulations of cells from a heteroge determined by both the intrinsic properties of tumor cells and neous tumor. Cell lines established from subcutaneous tumors by host factors. The latter are likely to be important in main or kidney tumors differed in their biological properties, and tenance of self, i.e., homeostasis. Factors that control the proc preliminary cytogenetic analysis by Sen Pathak suggests that esses of organ repair and/or regeneration are known to be organ each cell line has a distinct karyotype. This finding raises a specific. For example, subsequent to a partial hepatectomy question as to how human tumor cell lines should be isolated (60%), the liver undergoes rapid cell division termed "regener for the study of biology and therapy. Second, the implantation ation." In a hepatectomized mouse, however, no similar cell of cells from HRCC cell lines into the kidney of nude mice was division can be found in the kidneys. In contrast, the mouse associated with invasive and metastatic behavior. In contrast, kidney compensates for unilateral nephrectomy by hypertrophy the s.c. implantation of the same cells was associated with the and hyperplasia, whereas the liver does not regenerate after formation of a dense fibrous capsule surrounding the local nephrectomy. tumor. This finding indicates that the appropriate nude mouse Janet Price, Jerald Killion, Hans Schackert, and I carried out model for studying the biology and therapy of human cancers transplantation experiments on human colon carcinomas and must be based on orthotopic implantation of tumor cells. human renal cell carcinomas in nude mice that have subse- 6135

Downloaded from cancerres.aacrjournals.org on September 27, 2021. © 1990 American Association for Cancer Research. CRITICAL FACTORS IN HUMAN CANCER METASTASIS quently been subjected to either nephrectomy, hepatectomy of metastatic cells with their environment may open a new (60%), or abdominal surgery (as a trauma control). The results avenue for therapeutic intervention by inhibiting growth of were intriguing. Human colon carcinoma cells implanted s.c. mÃ©tastases. demonstrated accelerated growth in partially hepatectomized So now once again I ask the question: Is the process of cancer mice but not in nephrectomized mice. Human renal cell carci metastasis random or is it selective? The data I presented in noma cells established as micrometastases in the lung of nude this paper conclude that metastasis is a highly selective process mice underwent a significant growth acceleration subsequent to that is regulated by a number of different mechanisms. This unilateral nephrectomy but not hepatectomy. In other words, belief is quite contrary to the once widely accepted notion that liver regeneration in nude mice stimulated growth of HCC cells, metastasis represents the ultimate expression of cellular an whereas hypertrophy-hyperplasia of the kidney stimulated the archy. In fact, the view that cancer metastasis is a selective growth of human renal cancer cells. In both studies, the human process is an optimistic one. Belief that certain rules govern cancer cells were recent isolates from surgical specimens of metastasis implies that elucidation and understanding of these human cancers. rules will lead to better therapeutic intervention. This is an These results indicate that metastatic cells can respond to exciting time because we can now approach research on cancer physiological signals produced when homeostasis is disturbed, metastasis on the systemic, cellular, and molecular levels. I am i.e., the processes of repair and regeneration. Damage to the exceedingly fortunate to have been able to contribute to these organs is followed first by inflammation. Subsequent repair worthwhile endeavors and eagerly look forward to continued then stimulates the growth of normal cells. Tumor cells that increase in our knowledge. either originate from or have an affinity for growth in this particular organ can also respond to these signals. Acknowledgments

The work presented here could not have been accomplished without Conclusions the dedication and invaluable help of my colleagues, fellows, and students. I thank Lola Lopez for her help in preparing this manuscript In my presentation, I have stressed the following four points: and dedicate this lecture to my teacher, Irving Zeidman, and my friend (a) the process of metastasis is sequential and selective, with and collaborator, Margaret Kripke. every step of the process containing stochastic elements, and the growth of mÃ©tastasesrepresents the end point of many References lethal events that only few tumor cells can survive; (b) primary neoplasms have heterogeneous metastatic properties, and the 1. Fidler, I. J. Tumor heterogeneity and the biology of cancer invasion and outcome of metastasis is determined by the interaction of metastasis. Cancer Res., 38: 2651-2660. 1978. 2. Fidler, I. J., Gersten, D. M., and Hart, I. R. The biology of cancer invasion metastatic cells with various host factors, which include im and metastasis. Adv. Cancer Res., 28: 149-250, 1978. munity [I was warned not to mention the word macrophage, 3. Fidler, I. J. The evolution of biological heterogeneity in metastatic neo plasms. In: G. L. Nicolson and L. Milas (eds.). Cancer Invasion and and I promised not to utter the word macrophage even once Metastasis: Biologic and Therapeutic Aspects, pp. 5-30. New York: Raven (114)]; (c) the orthotopic implantation of human tumor cells Press, 1984. into nude mice can provide a model to study the biology and 4. Fidler. I. J., and Balch, C. M. The biology of cancer metastasis and implications for therapy. Curr. Probi. Surg., 24: 137-209, 1987. therapy of human cancer metastasis. Perhaps the processes of 5. Fidler. I. J., and Hart. I. R. Biological diversity in metastatic neoplasms: inflammation and repair subsequent to a trauma stimulate the origins and implications. Science (Washington DC), 217: 998-1003, 1982. growth of metastatic cells that either originate from or are 6. Willis, R. A. The Spread of Tumors in the Human Body. London: Butter- worths, 1972. capable of growing in the particular organ; (d) the outcome of 7. Poste, G., and Fidler, I. J. The pathogenesis of cancer metastasis. Nature metastasis is influenced by both the intrinsic properties of the (Lond.), 283: 139-146, 1979. tumor cell (seed) and host factors (soil) (Table 1). Thus, the 8. Sugarbaker, E. V. Cancer metastasis: a product of tumor-host interactions. successful metastatic cell, that 10 years ago I called the "de Curr. Probi. Cancer, 3: 1-59, 1979. 9. Weiss, L. Principles of Metastasis. Orlando, FL: Academic Press, 1985. cathlon champion" (1), must also be viewed as a cell receptive 10. Nicolson, G. L. Generation of phenotypic diversity and progression in metastatic tumor cells. Cancer Metastasis Rev., 3: 25-42, 1984. to its new environment. Indeed, understanding the interaction 11. Heppner, G. Tumor heterogeneity. Cancer Res., 44: 2259-2265, 1984. 12. Dexter, D. L., and Leith, J. T. Tumor heterogeneity and drug resistance. J. Table 1 Properties of tumor cells and host factors that regulate cancer metastasis Clin. Oncol.. 4: 244-257, 1986. 13. Nicolson, G. L., and Poste, G. Tumor cell diversity and host responses in I. Tumor cell properties cancer metastasis. I. Properties of metastatic cell. Curr. Probi. Cancer, 6: A. Facilitation of metastasis 4-83, 1982. 1. Production of growth factors and their receptors. 14. Fidler. I. J., and Poste, G. The cellular heterogeneity of malignant neo 2. Production of angiogenic factors. plasms: implications for adjuvant chemotherapy. Semin. Oncol.. 12: 207- 3. Motility. invasiveness. 221, 1985. 4. Aggregation, deformibility. 15. Poste, G. Pathogenesis of metastatic disease: implications for current ther 5. Specific cell surface receptors and adhesion molecules. apy and for the development of new therapeutic strategies. Cancer Treat. B. Inhibition of metastasis Rep., 70: 183-199, 1986. Amigenicity. 16. Folkman. J. Angiogenesis: initiation and modulation. In: G. L. Nicolson, and L. Milas (eds.). Cancer Invasion and Metastasis: Biologic and Thera II. Host factors peutic Aspects, pp. 201-209. New York: Raven Press, 1984. A. Facilitation of metastasis 17. Folkman, J. How is blood vessel growth regulated in normal and neoplastic 1. Neovascularization. tissue? G. H. A. Clowes Memorial Award Lecture. Cancer Res., 46: 467- 2. Paracrine and endocrine growth factors. 473, 1986. 3. Platelets and their products. 18. Folkman, J., and Klagsburn, M. Angiogenic factors. Science (Washington 4. Immune cells and their products. DC), 235: 444-447. 1987. B. Inhibition of metastasis 19. Gabbert, H. Mechanisms of tumor invasion: evidence from in vivo obser 1. Tissue barriers. vations. Cancer Metastasis Rev., 4: 283-310, 1985. 2. Blood turbulence, endothelial cells. 20. Liotta, L. A. Tumor invasion and metastasisâ€”role of the extracellular 3. Tissue inhibitors of degradative enzymes. matrix: Rhoads Memorial Award Lecture. Cancer Res., 46: 1-7, 1986. 4. Tissue antiproliferative factors. 21. Liotta. L. A., Rao, C. N., and Barsky. S. H. Tumor invasion and the 5. Immune cells and their products. extracellular matrix. Lab. Invest.. 49: 636-649, 1983. 6136

22. Marcel. M. Invasion in vitro: methods of analysis. Cancer Metastasis Rev., origin. J. Nati. Cancer Inst., 67: 947-956. 1981. 2:201-209, 1983. 55. Fidler, I. J., Gersten, D. M., and Kripke, M. L. Influence of immune status 23. Fisher, B., and Fisher, E. R. The interrelationship of hematogenous and on the metastasis of three murine fÃ¬brosarcomasof different immunogenic- lymphatic tumor cell dissemination. Surg. Gynecol. Obstet., 122: 791-797, ities. Cancer Res.. 39: 3816-3821. 1979. 1966. 56. Kripke, M. L. Immunoregulation and carcinogenesis: past, present, and 24. Nicolson, G. L. Cancer metastasis: tumor cell and host organ properties future. J. Nati. Cancer Inst., 80: 722-727. 1988. important in metastasis to specific secondary sites. Biochim. Biophys. Acta, 57. Frost. P.. and Kerbel, R. S. Immunology of metastasis: can the immune 948: 175-224. 1988. response cope with disseminated tumor? Cancer Metastasis Rev., 2: 239- 25. Horak, E.. Darling, D. L.. and Tarin. D. Analysis of organ-specific effects 256, 1983. on metastatic tumor formation by studies in vitro. 3. Nati. Cancer Inst., 76: 58. Fidler, I. J., and Kripke, M. L. Tumor cell antigenicity, host immunity, and 913-922, 1986. cancer metastasis. Cancer Immunol. Immunother., 7: 201-205, 1980. 26. Naito. S., Giavazzi, R., and Fidler. I. J. Correlation between the in vitro 59. Aukerman, S. L., Price, J. E., and Fidler. I. J. Different deficiencies in the interaction of tumor cells with an organ environment and metastatic behav prevention of tumorigenic-low-metastatic murine K-1735 melanoma cells ior in rivo. Invasion Metastasis. 7: 16-29, 1987. from producing mÃ©tastases.J. Nati. Cancer Inst., 77: 915-924, 1986. 27. Price, J. E.. Tarin. D., and Fidler. I. J. The influence of organ microenvi- 60. Fidler, I. J. Rationale and methods for the use of nude mice to study the ronment on pigmentation of a metastatic murine melanoma. Cancer Res., biology and therapy of human cancer metastasis. Cancer Metastasis Rev., 48: 2258-2264, 1988. 5:29-49, 1986. 28. Price, J. E., Naito, S., and Fidler. I. J. The role of the organ microenviron- 61. Price, J. E., Aukerman, S. L., and Fidler, 1. J. Evidence that the process of ment in the selective process of metastasis. Clin. Exp. Metastasis, 6: 91- murine melanoma metastasis is sequential and selective and contains sto 102, 1988. chastic elements. Cancer Res., 46: 5172-5178, 1986. 29. Weiss, L. Metastatic inefficiency: causes and consequences. Cancer Rev., 3: 62. Fidler. I. J., Gersten. D. M., and Riggs. C. W. Relationship of host immune 1-24, 1986. status to tumor cell arrest, distribution, and survival in experimental ani 30. Fidler. I. J. Metastasis: quantitative analysis of distribution and fate of mals. Cancer (Phila.), 40: 46-55, 1977. tumor cell emboli labeled with '"l-5-iododeoxyuridine. J. Nati. Cancer 63. Hart, I. R., Talmadge, J. E., and Fidler, I. J. Metastatic behavior of a Inst., 45: 773-782. 1970. murine reticulum cell sarcoma exhibiting organ-specific growth. Cancer 31. Fidler. I. J. Selection of successive tumor lines for metastasis. Nat. New Res., 41: 1281-1287. 1981. Biol.. 242: 148-149. 1973. 64. Fidler, I. J., and Talmadge, J. E. Evidence that intravenously derived murine 32. Nicolson, G. L., and Dulski. K. M. Organ specificity of metastatic tumor pulmonary mÃ©tastasescan originate from the expansion of a single tumor colonization is related to organ-selective growth properties of malignant cell. Cancer Res., 46: 5167-5171, 1986. cells. Int. J. Cancer. 38: 289-294, 1986. 65. Page!. S. The distribution of secondary growths in cancer of the breast. 33. Raz. A.. Hanna. N.. and Fidler, I. J. In vivo isolation of a metastatic tumor Lancet. /: 571-573, 1889. Hart, I. R. "Seed and soil" revisited: mechanisms of site-specific metastasis. cell variant involving selective and nonadaptive processes. J. Nati. Cancer 66. Inst., 66: 183-194. 1981. Cancer Metastasis Rev., /: 5-17, 1982. 34. Talmadge. J. E.. and Fidler. 1. J. Cancer metastasis is selective or random 67. Hart, I. R., and Fidler, I. J. Role of organ selectivity in the determination depending on the parent tumor population. Nature (Lond.), 27: 593-594, of metastalic patterns of B16 melanoma. Cancer Res., 41:1281-1287,1981. 1978. 68. Netland. P. A., and Zetter, B. R. Metastatic potential of B16 melanoma 35. Fidler, I. J. General considerations for studies of experimental cancer cells after in vitro selection for organ-specific adherence. Cell Biol., 101: metastasis. In: H. Bush (ed.). Methods in Cancer Research, pp. 399-439. 720-724, 1985. New York: Academic Press, 1978. 69. Ewing, J. Neoplastic Diseases, Ed. 6. Philadelphia: W. B. Saunders Co.. 36. Poste. G. Experimental systems for analysis of the malignant phenotype. 1928. Cancer Metastasis Rev., /: 141-200, 1982. 70. Tarin. D., Price. J. E.. Kettlewell. M. G. W., Souter, R. G., Vass, A. C. R., 37. Talmadge. J. E., and Fidler. I. J. Enhanced metastatic potential of tumor and Crossley. B. Mechanisms of human tumor metastasis studied in patients cells harvested from spontaneous mÃ©tastasesof heterogeneous murine tu with peritoneovenous shunts. Cancer Res., 44: 3584-3592, 1984. mors. J. Nati. Cancer Inst.. 69: 975-980. 1982. 71. Tarin, D., Price, J. E., Kettlewell, M. G. W., Souter, R. G., Vass, A. C. R., 38. Raz. A., and Hart. I. Murine melanoma: a model for intracranial metastasis. and Crossley, B. Clinicopathological observations on metastasis in man Br. J. Cancer. 42: 331-341. 1980. studied in patients treated with peritoneovenous shunts. Br. Mcd. J., 288: 39. Brunson. K. \V., and Nicolson, G. L. Selection and biologic properties of 749-751, 1984. malignant variants of a murine lymphosarcoma. J. Nati. Cancer Inst.. 61: 72. Schackert. G., and Fidler, 1. J. Development of in vivo models for studies 1499-1503, 1978. of brain metastasis. Int. J. Cancer, 41: 589-594, 1988. 40. Fidler. I. J.. Gersten, D. M., and Budmen. M. B. Characterization in vivo 73. Schackert, G., and Fidler, I. J. Site-specific metastasis of mouse melanomas and in vitro of tumor cells selected for resistance to syngeneic lymphocyte- and a fibrosarcoma in the brain or the meninges of syngeneic animals. mediated cytotoxicity. Cancer Res.. 36: 3160-3165. 1976. Cancer Res.. 48: 3478-3483, 1988. 41. Fidler. I. J., and Bucana. C. D. Mechanism of tumor cell resistance to lysis 74. August, D. A., Ottow, R. T., and Sugarbaker, P. H. Clinical perspectives of by syngeneic lymphocytes. Cancer Res., 37: 3945-3956, 1977. human colorectal cancer metastasis. Cancer Metastasis Rev., 3: 303-325, 42. Briles. E. B.. and Kornfeld. S. Isolation and metastatic properties of detach 1984. ment variants of B16 melanoma cells. J. Nati. Cancer Inst., 60:1217-1222, 75. Pollack. V. A., and Fidler, I. J. Use of young nude mice for selection of 1978. subpopulations of cells with increased metastalic potential from nonsynge- 43. Reading. C. L., and Hutchins. J. T. Carbohydrate structure in tumor neic neoplasms. J. Nati. Cancer Inst., 69: 137-141, 1982. immunity. Cancer Metastasis Rev., 4: 221-260. 1985. 76. Giavazzi, R., Campbell, D. E., Jessup, J. M. Cleary, K.. and Fidler, I. J. 44. Hart. I. R. The selection and characterization of an invasive variant of the Metastatic behavior of tumor cells isolated from primary and metastatic B16 melanoma. Am. J. Palhol.. 97: 587-600. 1979. human colorÃ©ela!carcinomas implanted into different sites of nude mice. 45. Poste. G.. Doll. J.. Hart. I. R.. and Fidler. I. J. In vitro selection of murine Cancer Res., 46: 1928-1933. 1986. BI6 melanoma variants with enhanced tissue invasive properties. Cancer 77. Giavazzi. R.. Jessup. J. M., Campbell, D. E., Walker. S. M., and Fidler, l. Res.. 40: 1636-1644. 1980. J. Experimental nude model of human colorectal cancer liver metastasis. J. 46. Sloane. B. F., and Honn. K. V. Cysteine proteinase and metastasis. Cancer Nati. Cancer Inst., 77: 1303-1308, 1986. Metastasis Rev.. 3: 249-265, 1984. 78. Sordat, B. C. M., Ueyama, Y., and Fogh, J. Metastasis of tumor xenografts 47. Kerbel. R. S. Immunologie studies of membrane mutants of a highly in the nude mouse. In: 3. Fogh and B. C. Giovanella (eds.). The Nude Mouse mctastalic murine tumor. Am. J. Pathol.. 97:609-616. 1979. in Experimental and Clinical Research, Vol. 2, pp. 95-147. New York: 48. Kerbel, R. S., Dennis, J. W., Lagarde, A. E., and Frost, P. Tumor progres Academic Press, 1982. sion in metastasis: an experimental approach using lectin-resistant tumor 79. Kozlowski. J. M., Fidler, I. J., Campbell, D., Xu, Z., Kaighn, M. E., and variants. Cancer Metastasis Rev., /: 99-140, 1982. Hart. I. R. Metastatic behavior of human tumor cell lines grown in the nude 49. Hanna. N. Role of natural killer cell in control of cancer metastasis. Cancer mouse. Cancer Res., 44: 3522-3529, 1984. Metastasis Rev., /: 45-65. 1982. 80. Naito, S., von Eschenbach, A. C., Giavazzi, R., and Fidler, I. J. Growth 50. Fidler. I. J., and Kripke. M. L. Metastasis results from pre-existing variant and metastasis of tumor cells isolated from a human renal cell carcinoma cells within a malignant tumor. Science (Washington DC). 797: 893-895, implanted into different organs of nude mice. Cancer Res., 46: 4109-4115, 1977. 1986. 51. I mia. S. E., and Delbruck. M. Mutations of bacteria from virus sensitive 81. Morikawa. K.. Walker. S. M., Jessup, J. M., and Fidler, I. J. In vivo to virus resistance. Genetics, 28: 491-511. 1943. selection of highly metastatic cells from surgical specimens of different 52. Kripke. M. L. Speculation on the role of ultraviolet radiation in the human colon carcinomas implanted into nude mice. Cancer Res., 48: 1943- development of malignant melanoma. J. Nati. Cancer Inst., 63: 541-545, 1948. 1988. 1979. 82. Morikawa. K., Walker, S. M., Nakajima, M., Pathak. S., Jessup. J. M., and 53. Fidler. I. J.. and Kripke. M. L. Metastatic heterogeneity of cells from the Fidler. I. J. Influence of organ environment on the growth, selection, and K-1735 melanoma. In: E. Grundmann (ed.). Metastatic Tumor Growth, pp. metastasis of human colon carcinoma cells in nude mice. Cancer Res., 48: 71-81. Stuttgart: Gustav Fischer Verlag, 1980. 6863-6871, 1988. 54. Fidler, I. J., Gruys, E.. Cifone, M. A., Barnes, Z., and Bucana. C. Demon- 83. Jessup. J. M., Giavazzi, R., Campbell, D., Cleary, K. R., Morikawa, K., stration of multiple phenotype diversity in a murine melanoma of recent Hosteller, R., Atkinson. E. N., and Fidler, I. J. Metastatic potential of 6137

human colorectal carcinomas implanted into nude mice: prediction of clin 99. Shafie, S. M.. and Liotta. L. A. Formation of metastasis by human breast ical outcome in patients operated upon for cure. Cancer Res., 49: 6906- carcinoma cells (MCF-7) in nude mice. Cancer Lett.. //: 81-87. 1980. 6910. 1989. 100. Price. J. E.. Polyzos, A., Zhang. R. D.. and Daniels. L. M. Tumorigenicity 84. Jessup, J. M. Giavazzi, R., Campbell. D., Clear), K.. Morikawa, K.. and and metastasis of human breast carcinoma cell lines in nude mice. Cancer Fidler. 1.J. Growth potential of human colorectal carcinomas in nude mice: Res., 50:717-721. 1990. association with preoperative serum concentration of carcinoembryonic 101. Levy, J. A., White, A. C.. and McGrath, C. M. Growth and histology of a antigen. Cancer Res.. 48: 1689-1692. 1988. human mammary-carcinoma cell line at different sites in the athymic mouse. 85. Thombre, P. S.. and Doedhar. S. D. Inhibition of liver mÃ©tastasesinmurine Br. J. Cancer. 45: 375-383, 1982. colon adenocarcinoma by liposomes containing human C-reactive protein 102. Ibrahiem. E. H. I., Nigam. V. N., Brailovsky. C. A., Madamas. P.. and or crude lymphokines. Cancer Immunol. Immunother., 16: 145-150, 1984. Miniali. M. Orthotopic implantation of primary (iV-[4-(5-nitro-2-furyl)-2- 86. Goldroscn, M. H. Murine colon adenocarcinoma immunobiology of mÃ©tas thiazolyljformamide-induced bladder cancer in bladder submucosa: an ani tases. Cancer (Phila.). 45: 1223-1228, 1980. mal model for bladder cancer study. Cancer Res., 43: 617-622, 1983. 87. Bresalier. R. S., Raper. S. E., Hujanen. E. S.. and Kim. V. S. A new model 103. Ahlering, T. E.. Dubeau. L.. and Jones. P. A. A new in vivo model to study for human colon cancer metastasis. Int. J. Cancer, 39: 625-630, 1987. invasion and metastasis of human bladder carcinoma. Cancer Res., 47: 88. Sordat. B.. and Wang. W. R. Human colorectal tumor xenografts in nude 6660-6665, 1987. mice: expression of malignancy. Behring Inst. Mitt.. 74: 291-300, 1984. 104. Kajiji, S. M., Meitner, P. A., Bogaars. H. A., Dexter, D. L., Calabresi, P., 89. dayman, R. V., Figenshau. R. S., and Bear, A. Transplantation of human and Turner, M. D. Metastasis of a human pancreatic adenocarcinoma renal carcinomas into athymic mice. Cancer Res., 45: 2650-2653, 1985. (RWP-1) in nude mice. Br. J. Cancer. 40:970-975, 1982. 90. Hoehn. W. A., and Schroeder. F. H. Renal cell carcinoma: two new cell 105. Vezeridis, M. P., Turner, M. D., Kajiji, S. M., Yankee. R. A., and Meither. lines and a serially transplantable nude mouse tumor (NC 65). Invest. Urol., P. A. Metastasis of human pancreatic cancer (HPC) to liver in nude mice. 16: 106-112, 1978. Proc. Am. Assoc. Cancer Res., 26: 53, 1985. 91. Naito. S., Kanamori. T., and Hisano, S. Human renal cell carcinoma: 106. Tan, M. H., and Chu, T. M. Characterization of the tumorigenic and establishment and characterization of two new cell lines. J. Urol., 128: metastatic properties of a human pancreatic tumor cell line (ASPC-1) 1117-1121, 1982. implanted orthotopically into nude mice. Tumour Biol., 6: 89-98. 1985. 92. Naito, S., von Eschenbach. A. C.. and Fidler. 1. J. Different growth pattern 107. Marincola. F. M.. Drucker, B. J., Siao, D. Yâ€žHough. K. L., and Holder. and biologic behavior of human and renal cell carcinoma implanted into W. D.. Jr. The nude mouse as a model for the study of human pancreatic different organs of nude mice. J. Nail. Cancer Inst., 78: 377-385, 1987. cancer. J. Surg. Res.. 47: 520-529, 1989. 93. Wang, W. R., Sordat. B., Paiguet, D., and Sordat, M. Human colon tumors 108. Vezeridis, M. P., Doremus, C. M., Tibbetts, L. M., Tzanakakis. G., and in nude mice: implantation site and expression of the invasive phenotype. Jackson. B. T. Invasion and metastasis following orthotopic transplantation In: B. Sordat (ed.). Immune-deficient Animals, pp. 239-245. Basel: S. of human pancreatic cancer in the nude mouse. J. Surg. Oncol.. 40: 261- Karger AG. 1984. 265. 1989. 94. Schackert. H.. and Fidler. I. J. Development of an animal model to study 109. McLemore. T. L., Liu. M. C. Blacker, P. C., Gregg, M.. Alley, M. C., the biology of recurrent colorectal cancer originating from mesenteric lymph Abbott, B. J., Shoemaker, R. H.. Bohlman. M. E.. Litters!, C. C., Hubbard. system mÃ©tastases.Int. J. Cancer. 44: 177-181, 1989. W. C., Brennan. R. H.. McMahon, J. B., Fine, D. L.. Eggleston. J. C, 95. Kozlowski. J. M., Hart, I. R., Fidler. I. J.. and Hanna. N. A human Mayo. J. G.. and Boyd, M. R. Novel intrapulmonar)' model for orthotopic melanoma line heterogeneous with respect to metastatic capacity in athymic propagation of human lung cancers in athymic nude mice. Cancer Res., 47: nude mice. J. Nati. Cancer Inst.. 72: 913-917. 1984. 5132-5140, 1987. 96. Kerbel. R. S., Man, M. S., and Dexter, D. A model of human cancer 110. Meyvisch, C. Influence of implantation site on formation of metastasis. metastasis: extensive spontaneous and artificial metastasis of a human Cancer Metastasis Rev.. 2: 295-306, 1983. pigmentcd melanoma and derived variant sublines in nude mice. J. Nati. 111. Poste, G. Experimental systems for analysis of the malignant phenotype. Cancer Inst.. 72:93-108, 1984. Cancer Metastasis Rev., /: 141-199. 1982. 97. Kerbel. R. S., and Man, M. S. Single-step selection of unique human 112. Miller. F. R. Comparison of metastasis of mammary tumors growing in the melanoma variants displaying unusually aggressive metastatic behavior in mammary fatpad versus the subcutis. Invasion Metastasis, 7:220-226,1981. nude athymic mice. Invasion Metastasis, 4: 31-43, 1984. 113. Malave, !.. Blanca, I., and Fuji. H. Influence of inoculation site on devel 98. Cornil, T., Man. M. S., Fernandez, B., and Kerbel. R. S. Enhanced tumor- opment of the Lewis lung carcinoma and suppressor cell activity in syngeneic igenicity. melanogenesis and metastasis of the human malignant melanoma mice. J. Nati. Cancer Inst.. 62: 83-88. 1979. observed after subdermal implantation in nude mice. J. Nati. Cancer Inst.. 114. Fidler, I. J. Macrophages and metastasis: a biological approach to cancer 81: 938-944. 1989. therapy. Cancer Res., 45: 4714-4726. 1985.

6138

Downloaded from cancerres.aacrjournals.org on September 27, 2021. © 1990 American Association for Cancer Research. Critical Factors in the Biology of Human Cancer Metastasis: Twenty-eighth G. H. A. Clowes Memorial Award Lecture

Isaiah J. Fidler

Cancer Res 1990;50:6130-6138.

Updated version Access the most recent version of this article at: http://cancerres.aacrjournals.org/content/50/19/6130

E-mail alerts Sign up to receive free email-alerts related to this article or journal.

Reprints and To order reprints of this article or to subscribe to the journal, contact the AACR Publications Subscriptions Department at [email protected].

Permissions To request permission to re-use all or part of this article, use this link http://cancerres.aacrjournals.org/content/50/19/6130. Click on "Request Permissions" which will take you to the Copyright Clearance Center's (CCC) Rightslink site.