81-91 11/12/07 12:26 Page 81 ONCOLOGY REPORTS 19: 81-91, 2008 81 Significance of the glycolytic pathway and glycolysis related- genes in tumorigenesis of human colorectal cancers CHING-SHENG YEH1,7, JAW-YUAN WANG2,5, FU-YEN CHUNG1, SU-CHEN LEE4, MING-YII HUANG1,6, CHIA-WEI KUO3, MING-JE YANG1 and SHIU-RU LIN3 1Graduate Institute of Medicine, 2Faculty of Medicine, 3Graduate Institute of Medical Genetics and 4Department of Clinical Laboratory, College of Medicine, Kaohsiung Medical University; Departments of 5Surgery, 6Radiation Oncology and 7Labortory, Kaohsiung Medical University Hospital, Kaohsiung 80317, Taiwan, R.O.C. Received June 13, 2007; Accepted August 17, 2007 Abstract. We investigated gene expressions involved in the new cases and 200,000 deaths due to CRC are reported in glycolytic pathways in colorectal cancer. The study was these areas (1-3). CRC is also one of the most frequent designed to use gene ontology and its relevant bioinformatics malignancies and has the third highest mortality rate of all tools to analyze the microarray data obtained from CRC tissues the cancers in Taiwan, affecting and causing over 7,000 new and their corresponding normal tissues, in order to explore cases and 3,000 deaths per year (4-6). As investigative studies the correlation between the glycolytic metabolic pathway and have reported, approximately 30-40% of CRC patients who possible pathogenesis of this disease. The overexpression of have undergone curative resection afterwards develop glycolysis-related genes was observed in over 76% of CRC metastatic disease and die within 5 years (7,8). tissues. In addition, we stimulated the SW480 and SW620 Little is known about the details of the molecular CRC cell lines with 15 mM D-(+)-glucose and 10 mM 2- mechanism of CRC development; therefore, difficulties exist deoxy-D-glucose respectively. The results indicate that the in its prevention and treatment. Consequently, knowing how to proliferation response of both the SW480 and SW620 cell rapidly organize new techniques for exploring the molecular lines increased remarkably with a time-dependent effect by mechanisms of CRC is key to providing researchers with D-(+)-glucose administration. In contrast, the proliferation the information regarding detailed functional analyses of response of both the SW480 and SW620 cell lines was turmorigenesis. In order to explore the molecular mechanisms significantly inhibited by 2-DG administration. Likewise, underlying the tumorigenesis of CRC, high-throughput and further analyses of the expression of related genes triggered efficient tools are used, such as comparative genomic by the D-(+)-glucose in vivo show that the activation process hybridization (CGH), microarray and proteomics, which can of these eight genes - GLUT1, HK1, GPI, GAPD, PGK1, analyze the activation of differential molecular factors PGK2, ENO2, PKM2 - prominently increased with a time- between the normal mucosal tissues and the cancerous dependent effect. In conclusion, this study demonstrates that tissues. Afterwards bioinformatics tools are employed to the glycolytic pathway and glycolysis-related genes may play predict the relevant mechanisms of CRC turmorigenesis. an important role in the tumorigenesis of CRC, but their Previously, we have observed that constructed membrane- molecular mechanisms need further investigation to verify this. array techniques can be effective and efficient for the confirmation of overexpression of related genes in human Introduction cancerous tissues (9-11). Recently, we have demonstrated that fatty acid metabolism plays an important role in turmori- Colorectal cancer (CRC) is a primary cause of morbidity and genesis of human CRCs by microarray-bioinformatics analysis mortality in Europe and the USA. Each year, about 300,000 (12). We have also obtained preliminary results from the same experiments that indicate the glycolysis pathway might be imperative for tumorigenesis of CRC. Although several _________________________________________ studies have proved that malignant tumor cells increase the glycolytic activity in many malignant diseases in vivo and Correspondence to: Dr Shiu-Ru Lin, Graduate Institute of in vitro (13-16), whether the glycolytic pathway and Medical Genetics, College of Medicine, Kaohsiung Medical glycolysis-related genes participate in tumorigenesis of University, Kaohsiung 80317, No. 100, Shin-Chuan 1st Road, human CRC has yet to be elucidated. Taiwan, R.O.C. In this study therefore, we first attempted to verify the E-mail: [email protected] activation of these genes relevant to the glycolytic pathway in human CRC tissues. Moreover, we stimulated the CRC Key words: glycolytic pathways, glycolysis related-genes, mem- cell lines by D-(+)-glucose and 2-deoxy-D-glucose (2-DG, a brane array, 2-deoxy-D-glucose, turmorigenesis, colorectal cancer non-metabolizable glucose analogue) and observed their effect on cell proliferation; in addition we inhibited the CRC cell line by 2-DG administration. Finally, we sought to clarify 81-91 11/12/07 12:26 Page 82 82 YEH et al: GLYCOLYTIC PATHWAYS AND GLYCOLYSIS-RELATED GENES IN CRC Table I. Clinicopathological characteristics of CRC patients. ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Age Size No. Sex (years) (cm) Differentiationa Location UICC ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– 3 F 54 4.2x3.0 MD Sigmoid colon II 9 F 48 8.8x5.6 PD Descending colon III 17 M 61 4.5x3.9 PD Descending colon III 20 M 70 2.0x1.5 WD Ascending colon I 25 F 58 6.7x2.9 MD Descending colon II 31 M 76 8.15x6.5 PD Rectum colon IV 45 M 27 5.0x3.8 MD Descending colon II 49 F 62 5.7x4.6 PD Descending colon III 64 F 55 3.0x4.5 WD Ascending colon I 75 M 71 10.5x5.7 MD Rectum II 78 M 70 5.85x4.1 PD Sigmoid colon IV 82 M 51 5.0x4.5 MD Descending colon II 85 F 59 7.2x6.2 PD Sigmoid colon IV 89 M 67 12.0x9.8 PD Rectum colon III 91 F 73 7.5x6.7 WD Rectum I 93 M 38 3.5x4.5 MD Rectum II 99 M 55 7.85x5.3 PD Sigmoid colon IV 102 F 93 4.0x3.5 MD Transverse colon II 116 F 85 8.2x3.7 PD Sigmoid colon IV 127 M 68 6.1x2.9 WD Ascending colon I 134 F 79 11.5x6.5 PD Sigmoid colon IV 143 M 71 10.5x7.8 PD Transverse colon III 157 M 66 5.8x4.0 PD Rectosigmoid colon III 179 F 53 3.8x7.2 WD Ascending colon I 207 F 66 3.2x2.9 MD Ascending colon II ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– aWD, well differentiated; MD, moderately differentiated; PD, poorly differentiated. ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– the possible molecular mechanisms underlying the turmori- 2002). The results showed 5 patients with UICC stage I, 8 genesis of CRC and its association to the glycolytic pathway with UICC stage II, 6 with UICC stage III and 6 with UICC and glycolysis-related genes. stage IV CRC (Table I). The surgical tissue samples upon acquisition were frozen instantly in liquid nitrogen, and then Patients and methods stored at -80˚C until analysis. All sample acquisition and subsequent use was also approved by the Institutional Sample collection. Twenty-five patients, ranging in age from Review Board of the Kaohsiung Medical University Hospital. 27 to 93 years (mean, 63.04), who had undergone resection of CRC, were selected randomly from a patient group at the Total-RNA extraction and first strand cDNA synthesis. Total- Department of Surgery of Kaohsiung Medical University RNA was isolated from patient tissue and cell specimen Hospital between August 2004 and January 2006. None of samples with Isogen™ (Nippon Gene Co., Ltd., Toyama, these patients had received any preoperative radiotherapy or Japan) and QIAmp® RNA Blood Mini Kit (Qiagen Inc., chemotherapy. Soon after resection, the specimens were Valencia, CA) according to the manufacturer's instructions opened in the operating room and photographed for (17). The RNA concentration was determined spectrophoto- documentation. According to the prospective protocol, the metrically on the basis of absorbance at 260 nm (Beckman, tumors and all the lymph nodes were cut at different levels DU800, USA). First strand cDNA was synthesized from and embedded in paraffin, and sections were taken for total-RNA by using a RT-PCR kit (Promega Corp., Madison, routine H&E staining. Senior pathologists checked all the WI). The reverse transcription was carried out in a reaction slides and documented the pathological characteristics of the mixture consisting of 1X transcription optimized 5X buffer, tumor and lymph nodes. The tumor stage was defined 25 μg/ml oligo(dT)15mer primer, 100 mmol/l PCR nucleotide according to the criteria of the American Joint Commission mix, 200 μmol/l M-MLV reverse transcriptase, and 25 μl of on Cancer/International Union Against Cancer (AJCC/UICC, recombinant RNasin® ribonuclease inhibitor (Promega). The 81-91 11/12/07 12:26 Page 83 ONCOLOGY REPORTS 19: 81-91, 2008 83 reaction mixtures with RNA were incubated at 42˚C for (CCL-228 and CCL-227; ATCC, Rockville, MD). The cells longer than 2 h, heated to 95˚C for 5 min, and then stored at were maintained in Leibovitz's L-15 medium (Gibco Life -80˚C until analysis. Sciences, BRL, Grand Island, NY) supplemented with 10% (v/v) of fetal bovine serum (FBS) at 37˚C in humidified Oligo membrane array preparation. The procedure of the atmospheric air without CO2 addition. All media was supple- membrane-array method for the detection of CRC-related mented with 100 units/ml penicillin, 100 mg/ml streptomycin genes was performed in accordance with our previous work and 0.025 mg/ml fungizone. Cell density was maintained at (9-11). Visual OMP3 (oligonucleotide modeling platform, ~10,000 cells per milliliter of medium in T-25 flasks (Corning, DNA Software, Ann Arbor, MN) was applied to design oligo- NY). When grown to confluent monolayer, the cells were nucleotide probe sequences for target genes and ß-actin, and harvested by washing the dishes once with phosphate-buffered the latter served as an internal control (Table II).