A Novel Autocrine CXCL14/ACKR2 Axis: the Achilles' Heel of Cancer Metastasis? Qian Zhang1, Nianxin Zhou1, Wei Wang1,2, and Shengtao Zhou1

Published OnlineFirst April 5, 2019; DOI: 10.1158/1078-0432.CCR-19-0853

CCR Translations Clinical Cancer Research A Novel Autocrine CXCL14/ACKR2 Axis: The Achilles' Heel of Cancer Metastasis? Qian Zhang1, Nianxin Zhou1, Wei Wang1,2, and Shengtao Zhou1

Cancer-associated ﬁbroblasts (CAF) are essential for cancer CXCL14/ACKR2 axis mediates epithelial-to-mesenchymal hallmarks. While CAFs are molecularly heterogeneous, a transition and endows metastatic traits, which offers novel CXCL14-expressing subset has been a critical player in the therapeutic potential in the clinical setting. cancer context. In breast cancer, an autocrine ﬁbroblast See related article by Sj€oberg et al.

In this issue of Clinical Cancer Research,Sjoberg€ and collea- a prosurvival milieu for cancer stem cells. Mechanistically, þ þ gues (1) discussed the epithelial-to-mesenchymal transition CD10 GPR77 CAFs are driven by continuous NF-kB activation (EMT)–inducing and metastasis-promoting roles of CXCL14- via p65 phosphorylation and acetylation. This process is expressing fibroblasts in breast cancer. These effects are primarily sustained by complement signaling via GPR77, a C5a receptor. þ þ achieved by autocrine indirect interactions between CXCL14 and In vivo, CD10 GPR77 CAFs promote successful engraftment of the atypical chemokine receptor 2 (ACKR2) in fibroblasts to patient-derived xenografts, whereas inhibition of these CAFs with induce downstream NOS1 signaling activation. a neutralizing anti-GPR77 antibody attenuates tumor formation Cancer-associated fibroblasts (CAF) constitute an important and restores the sensitivity of tumor cells to chemotherapy. These component of the tumor ecosystem. They are critical for tumor- studies further highlight the important role of CAFs in cancer igenesis and play an active role in cancer progression and devel- biology and underscore the possibility of CAF-targeting therapies opment of therapy resistance. CAFs could orchestrate the biology for patients with cancer. of both cancer cells and other stromal cells via either cell–cell CXCL14 is a non-ELR chemokine with diversified immune contact or by secreting soluble factor signals. They are intrinsically functions. At high concentrations, it serves as a chemoattractant heterogeneous and functionally diversified, as revealed by for dendritic cells, activated macrophages, and natural killer (NK) recent molecular and functional characterization. Recently, cells. In the cancer context, its functions seem paradoxical. Con- CAFs have been categorized into four molecular subsets in breast sistent with its immunological functions, CXCL14 was reported to cancer with different functions based upon different gene expres- promote NK cell–mediated inhibition of transplanted melanoma sion (2). Among them, differential accumulation of two myofi- cell metastasis in a CXCL14 transgenic mouse model (4). More- broblastic subsets (CAF-S1, CAF-S4) was found in triple-negative over, the therapeutic efficacy of angiogenic inhibitors was also breast cancers. CAF-S1 fibroblasts secrete CXCL12 to attract proved to be dependent on induction of CXCL14 in tumor mouse þ þ CD4 CD25 T cells and retain them by OX40L, PD-L2, and models (5). However, CXCL14 has also been reported to be tumor JAM2, maintaining an immunosuppressive tumor microenviron- promoting (6). In recent years, it was found that among those ment. CAF-S1 also promotes T-cell survival and induces their CAFs, there is a subgroup of cancer-promoting CAFs that express differentiation into CD25HighFOXP3High T cells, through B7H3, high level of the chemokine CXCL14. Augsten and colleagues CD73, and DPP4. In another study, Su and colleagues character- found that CXCL14-expressing fibroblasts could enhance the ized the molecular features and functions of a subset of CAFs that growth of prostate cancer xenografts, trigger tumor angiogenesis þ þ þ þ are CD10 GPR77 in cancer (3). They found that CD10 GPR77 and macrophage recruitment, and enhance monocyte migration. CAFs enhance tumor formation and chemoresistance by offering Autocrine CXCL14 stimulation of fibroblasts further triggers migration and ERK-dependent growth of fibroblasts (7). The same research group later found that this subset of CXCL14- 1Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and expressing fibroblasts depend on NOS1-derived nitric oxide Related Diseases of Women and Children of MOE, and State Key Laboratory of signaling for their tumor-supporting capacities (8). Moreover, Biotherapy, West China Second University Hospital, Sichuan University and it was demonstrated that CXCL14-expressing fibroblasts could Collaborative Innovation Center, Chengdu, P.R. China. 2Department of Biomed- promote ovarian cancer metastasis by triggering upregulation ical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong, P.R. China. of LINC00092 in ovarian cancer cells (9). Mechanistically, LINC00092 could bind to a glycolytic enzyme, fructose-2, Note: Q. Zhang and N. Zhou contributed equally to this article. 6-biphosphatase PFKFB2, to promote metastasis by changing Corresponding Author: Shengtao Zhou, West China Second Hospital, Sichuan cellular glycolytic level and maintaining the local supportive University, #20, the Third Section, Renmin South Road, Chengdu, Sichuan, function of CAFs. These properties of CXCL14-expressing 610041, P.R. China. Phone: 8613-5510-70137; Fax: 8628-8516-4046; E-mail: fi [email protected] broblasts have made CXCL14 a potential therapeutic target for cancer therapy. However, one issue that remains to be deter- Clin Cancer Res 2019 mined is that CXCL14, on one hand, could promote tumorigen- doi: 10.1158/1078-0432.CCR-19-0853 esis and cancer progression and, on the other hand, is a potent 2019 American Association for Cancer Research. chemokine that recruits antitumor immune cells and induces

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Zhang et al.

Cancer cells CAFs Figure 1. A schematic model that illustrates the molecular basis for the cross-talk between the NOS1 autocrine fibroblast CXCL14/ Vimentin ACKR2 axis and breast cancer E-cadherin ACKR2 cells. CXCL14-expressing Inhibitor/ fi Snail1 Inhibitor broblasts secrete CXCL14, antibody Autocrine which indirectly interacts with Receptor CXCL14 ACKR2 that expresses on the fibroblasts. This autocrine loop Paracrine activates a downstream NOS1 signaling cascade in fibroblasts, which in turn, acts on the cancer cells to initiate EMT programs. This cross-talk ultimately leads to enhanced metastatic potential EMT Increased metastasis for cancer cells. CXCL14 and ACKR2 constitute potential drug targets for the management of cancer metastasis. Straight arrows indicate activation of © 2019 American Association for Cancer Research downstream targets. Broken blocking signs indicate inhibition of targets.

immunosurveillance activity. Therefore, on what occasion a zation in a murine model. Loss-of-function screening experiments CXCL14-depleting strategy should be adopted and when a identified ACKR2 to be the effector of CXCL14-stimulated CXCL14 gain-of-function regimen should be used need to be responses. Further functional validation demonstrated that carefully assessed. downregulation of ACKR2, or CXCL14-induced NOS1 in fibro- ACKR2, previously known as D6, is a chemokine scavenging blasts, abolished the pro-EMT and migratory capacity. Clinically, receptor that belongs to the family of atypical chemokine recep- CXCL14/ACKR2 expression was proved to correlate with EMT and tors. It could bind with high affinity to proinflammatory CC clinical outcome in gene expression datasets of breast cancer. As chemokines and promote their intracellular degradation. Conse- both CXCL14 and ACKR2 are potentially druggable and action- quently, ACKR2 could function in ameliorating local inflamma- able in the clinical setting, this novel finding has offered us new tory responses, in the resolution of inflammation, and in the inspirations for the management of cancer metastasis (see Fig. 1). control of adaptive immune responses. Its cancer-promoting role As there are no existing CXCL14 antibody/inhibitors or ACKR2 has also been appreciated recently. Massara and colleagues inhibitors, currently no relevant clinical trials for cancer thera- reported that ACKR2 is expressed in hematopoietic precursors peutics could be identified. Future investigations could be and downregulated during myeloid differentiation (10). Genetic focused on the development of novel drugs that target the depletion of Ackr2 leads to higher expression level of inflamma- CXCL14/ACKR2 axis and the assessment of their therapeutic tory chemokine receptors and release of neutrophils from the efficacy in patients with cancer. Moreover, because the functions bone marrow with increased antimetastatic activity. In both of CXCL14 in cancer biology are somewhat ambiguous, we spontaneous and transplanted tumor murine models, Ackr2 defi- should also carefully evaluate the potential side effects and cancer ciency results in neutrophil-mediated protection against cancer risk when developing CXCL14-based targeted therapy drugs for metastasis. More recently, Hansell and colleagues demonstrated patients with cancer. that mice deficient in Ackr2 display impaired development of metastasis in vivo, because of increased CCR2 expression specif- þ / Disclosure of Potential Conflicts of Interest ically by KLRG1 NK cells from the Ackr2 mice (11). This þ No potential conflicts of interest were disclosed. resulted in KLRG1 NK cell infiltration to CCL2-expressing tumors and promoted tumor killing. Herein, Sjoberg€ and colleagues (1) reported that, although not directly interacting with Acknowledgments CXCL14, ACKR2 still mediates CXCL14-induced downstream S. Zhou is supported by grants from the National Natural Science NOS1 activation to enhance the cancer-promoting functions of Foundation of China (81822034 and 81773119), grants from the National fibroblasts. These findings raise the future possibility of drugging Key Research and Development Program of China (2017YFA0106800 and 2018YFA0109200), a grant from the Sichuan Science-Technology Interna- the ACKR2 for cancer therapeutics. fi € tional Cooperation Project (2019YFH0144), and Direct Scienti cResearch In this study by Sjoberg and colleagues (1), CXCL14-expressing Grants from West China Second Hospital, Sichuan University (KS021). fibroblasts could potently trigger EMT and enhance migration and invasion in breast cancer both in vitro and in vivo. Tumor cells Received March 19, 2019; revised March 28, 2019; accepted April 3, 2019; primed by CXCL14 fibroblasts exhibited enhanced lung coloni- published first April 5, 2019.

References 1. Sjoberg E, Meyrath M, Milde L, Herrera M, Lovrot J, Hagerstrand D, et al. to-mesenchymal transition and metastasis of breast cancer. Clin Cancer Res A novel ACKR2-dependent role of ﬁbroblast-derived CXCL14 in epithelial- 2019 Mar 8 [Epub ahead of print].

OF2 Clin Cancer Res; 2019 Clinical Cancer Research

Autocrine Fibroblast CXCL14/ACKR2 Axis in Cancer Metastasis

2. Costa A, Kieffer Y, Scholer-Dahirel A, Pelon F, Bourachot B, Cardon M, et al. modal stimulator of prostate tumor growth. Proc Natl Acad Sci U S A 2009; Fibroblast heterogeneity and immunosuppressive environment in human 106:3414–9. breast cancer. Cancer Cell 2018;33:463–79. 8. Augsten M, Sjoberg E, Frings O, Vorrink SU, Frijhoff J, Olsson E, et al. þ þ 3. Su S, Chen J, Yao H, Liu J, Yu S, Lao L, et al. CD10 GPR77 cancer- Cancer-associated fibroblasts expressing CXCL14 rely upon NOS1-derived associated fibroblasts promote cancer formation and chemoresistance by nitric oxide signaling for their tumor-supporting properties. Cancer Res sustaining cancer stemness. Cell 2018;172:841–56. 2014;74:2999–3010. 4. Hata R, Izukuri K, Kato Y, Sasaki S, Mukaida N, Maehata Y, et al. Suppressed 9. Zhao L, Ji G, Le X, Wang C, Xu L, Feng M, et al. Long noncoding rate of carcinogenesis and decreases in tumour volume and lung metastasis RNA LINC00092 acts in cancer-associated fibroblasts to drive gly- in CXCL14/BRAK transgenic mice. Sci Rep 2015;5:9083. colysis and progression of ovarian cancer. Cancer Res 2017;77: 5. Rivera LB, Meyronet D, Hervieu V, Frederick MJ, Bergsland E, Bergers G. 1369–82. Intratumoral myeloid cells regulate responsiveness and resistance to anti- 10. Massara M, Bonavita O, Savino B, Caronni N, Mollica Poeta V, angiogenic therapy. Cell Rep 2015;11:577–91. Sironi M, et al. ACKR2 in hematopoietic precursors as a checkpoint 6. Wang Y, Weng X, Wang L, Hao M, Li Y, Hou L, et al. HIC1 deletion promotes of neutrophil release and anti-metastatic activity. Nat Commun breast cancer progression by activating tumor cell/fibroblast crosstalk. 2018;9:676. J Clin Invest 2018;128:5235–50. 11. Hansell CAH, Fraser AR, Hayes AJ, Pingen M, Burt CL, Lee KM, et al. The 7. Augsten M, Hagglof C, Olsson E, Stolz C, Tsagozis P, Levchenko T, et al. atypical chemokine receptor Ackr2 constrains NK cell migratory activity CXCL14 is an autocrine growth factor for fibroblasts and acts as a multi- and promotes metastasis. J Immunol 2018;201:2510–9.

www.aacrjournals.org Clin Cancer Res; 2019 OF3

A Novel Autocrine CXCL14/ACKR2 Axis: The Achilles' Heel of Cancer Metastasis?

Qian Zhang, Nianxin Zhou, Wei Wang, et al.

Clin Cancer Res Published OnlineFirst April 5, 2019.

Updated version Access the most recent version of this article at: doi:10.1158/1078-0432.CCR-19-0853

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