The role of the C-terminal domain in the CXCR3 receptor in CXCL10-induced migration of ING4-deficient breast cancer cells
With limited treatment options, metastatic triple negative breast cancer (TNBC) has a 5-year patient survival of 12%. Up to 34% of all breast cancer tumors are deficient in the tumor suppressor Inhibitor of Growth 4 (ING4) and correlated with poor patient survival. Higher concentration of the chemokine CXCL10 in ING4-deficient TNBC incites cell migration and tumor metastasis in experimental systems. Clinically relevant, patients with CXCL10-high/ING4-low expressing breast tumors have significantly reduced disease-free survival. CXCL10 binds to the seven transmembrane domain G protein-coupled receptor CXCR3 to signal cell migration. The carboxyl-terminal intracellular domain of CXCR3 has been shown to promote chemotactic migration in lymphocytes. However, the specific effects of CXCR3’s carboxyl-terminus in TNBC is unknown. To investigate the specific effects of CXCR3’s carboxyl-terminus in TNBC, we first cloned the gene encoding for the mutant CXCR3 protein missing 40 amino acids on the c-terminus. Using retrovirus, we delivered the mutant construct into the MDA-MB-231 TNBC cell line deleted of ING4 and/or CXCR3. The expression of the mutant protein will be assessed via Western Blot. The functionality of the mutant will be evaluated using transwell cell migration assays in the presence of CXCL10.
