BBSRC Case Studentship- The role of the chemokine CXCL12 in cell-matrix interactions and ECM remodelling in biological processes

Background: The mechanisms underlining the interaction of the chemokine CXCL12 with its CXCR4 receptor are diverse. Both genes are highly conserved in evolution - knocking out either receptor or ligand in mice leads to embryonic lethality. Via signalling through its CXCR4 receptor, CXCL12 is involved in many essential processes such germ cell migration, cell-cell interactions and angiogenesis (1, 2). CXCL12 is also an important chemokine in malignant disease being produced by malignant and/or host cells in many cancers (3, 4). The lab of the Principal Applicant has generated evidence that CXCL12 acts as a survival factor for malignant cells; is a major mediator of an autocrine signalling network in these cells; is involved in tumour neovascularisation as well as in interactions between tumour and stroma (5-8). In this project we will investigate our unpublished data that strongly link CXCL12 gene expression levels in human tissue with pathways and processes associated with cell - matrix interactions and extra-cellular matrix, ECM, remodelling. In brief, we interrogated Affymetrix gene expression array datasets from 245 ovarian cancer biopsies to find genes whose expression correlated with levels of CXCL12 mRNA (Kulbe et al unpublished data). There was a significant association between high CXCL12 mRNA levels and pathways/processes associated with cell matrix interactions and ECM remodelling as well as expected associations to chemotaxis pathways. Individual genes significantly associated with high CXCL12 mRNA (cc>0.70) included ECM proteins, proteases and their inhibitors. There was significant overlap between ECM genes identified in this analysis and those up-regulated in chemoresistant ovarian cancer, suggesting that CXCL12 may be a key driver for this resistance signature (9). Hypothesis: In normal tissues and in pathological states, CXCL12 regulates cell migration by modulating a specific set of genes involved in cell-matrix interactions and ECM remodelling. Aims: The overall aim of this project is to analyze the role of CXCL12 in cell-matrix interactions and ECM remodelling. We will use gene expression array datasets, immortalised ovarian surface epithelial cells and cell lines from ovarian cancer in the following experimental approaches: A. Confirm and extend gene association studies that link CXCL12 levels with cell matrix interactions and extra-cellular matrix remodelling B. Investigate a role for CXCL12 in interactions between epithelial cells and the extra-cellular matrix or mesothelial cell monolayers. C. Investigate a role for CXCL12 in epithelial cell growth and survival. D. Investigate a role for CXCL12 in chemoresistance in ovarian cancer. The student will gain expertise in the following techniques: Tissue culture; RNA preparation and real-time RT-PCR; shRNA techniques and gene transfection; multiplex assays for cytokine release; cell proliferation and cell death assays; Affymetrix and bioinformatics. Expected outcomes: CXCL12 stimulates the migration of both normal and transformed cells during development, haematopoiesis, inflammation and malignancy. Based on preliminary data we suggest that one way this is achieved is via regulation of cell:matrix interactions and ECM remodelling. Knowledge gained from this project may have wide significance in cell biology. References 1. M. Doitsidou et al., Cell 111, 647 (2002). 2. A. Aiuti, I. J. Webb, C. Bleul, T. Springer, J. C. Gutierrez-Ramos, J Exp Med 185, 111 (1997). 3. F. Balkwill, Seminars in Cancer Biology 14, 171 (2004). 4. J. A. Burger, T. J. Kipps, Blood 107, 1761 (2006). 5. C. Scotton, D. Milliken, J. Wilson, S. Raju, F. Balkwill, Br J Cancer 85, 891 (2001). 6. D. Milliken, C. Scotton, S. Raju, F. Balkwill, J. Wilson, Clin Cancer Res 8, 1108 (2002). 7. H. Kulbe, T. Hagermann, P. W. Szlosarek, F. R. Balkwill, J. L. Wilson, Cancer Res 65, 10355 (2005). 8. H. Kulbe et al., Cancer Res 67, 585 (2007). 9. A. A. Jazaeri et al.