CRISPR/Cas9-mediated Gene Editing to Assess the Role of CXCR7 in Cervical Cancer

Abstract

Objective: Chemokine receptors and their corresponding chemokine ligands play a significant role in tumor cell survival and proliferation. CXCR7 is a receptor often overexpressed in different cancers including cervical cancer; however, its exact role in cancer initiation and progression remains unknown. Here we studied the expression and function of CXCR7 in human cervical cancer (HeLa cells) that helps us develop a potential novel targeted therapy. Methods and results: To understand the role of CXCR7 in cervical cancer, we compared the wild-type and CXCR7 knockdown, investigated cell signaling after stimulation by certain ligands (SDF-1 and I-TAC) and analyzed the cell behavior. RT-PCR analysis detected high expression of CXCR7, medium expression of CXCR4, and no expression of CXCR3 in HeLa cells. Using CRISPR/Cas9 approach, we successfully deleted CXCR7 gene on HeLa cells, which we validated using sequencing, flow cytometry, and Western blot analysis. Flow Cytometry analysis revealed CXCR7 protein level is significantly higher in wild type cells than knockout cell lines. The results of Western blot indicate that CXCR7 knockout increased phosphorylation of AKT and decreased phosphorylation of p38. Activation of CXCR7 by SDF-1 or I-TAC was found to inhibit the phosphorylation of AKT in a dose-dependent manner in WT group. On the functional level, we observed that the deletion of CXCR7 resulted in a significant increase in cell viability in comparison to WT cells. Conclusion: Our finding emphasizes the importance of CXCR7. We concluded that CXCR7 knockout activates AKT signaling and promotes HeLa cells survival, suggesting that CXCR7 is a suppressor for cervical cancer. This work reveals a new suppressive role of CXCR7 in cervical cancer cells, which may give us new understanding and treatment options for patients suffering from cervical cancer.