Panoply™ Human GPR77 Over-expressing Stable Cell Line

C5AR2 (GPR77, C5L2) is the second receptor for the potent complement protein C5a, which is produced upon complement activation. C5AR2 mediates its own signaling and, through these signaling pathways, exerts significant immunomodulatory effects. However, research on C5AR2 in cancer is limited, and its role in breast cancer remains unclear. Here, researchers demonstrate that C5AR2 expression varies between most cancerous and noncancerous tissues, with elevated C5AR2 expression significantly associated with poor prognosis in BRCA, GBM, KICH, LAML, LGG, LIHC, PAAD, and STAD. Furthermore, C5AR2 expression levels are closely correlated with known immune infiltration, particularly macrophage polarization, in breast cancer. Gene set enrichment analysis confirmed that C5AR2 regulates multiple signaling pathways related to tumorigenesis and tumor immunity. Consistent with bioinformatics analysis, C5AR2 overexpression promotes breast cancer cell migration, invasion, and proliferation, which is consistent with the results of bioinformatics analysis. C5AR2 is involved in immune infiltration and malignant features in breast cancer and may serve as a potential biomarker for breast cancer.

C5AR2 is most abundantly expressed in breast cancer tissues (Figure 1B), consistent with the finding in the CCLE database that C5AR2 is expressed at the highest levels in a small number of breast cancer cell lines within solid tumors. Subsequently, the researchers evaluated C5AR2 expression in various breast cancer cell lines and found that C5AR2 expression was relatively low in MDA-MB-231 cells (ER-negative) compared with T47D and MCF7 cells (ER-positive) (Figure 1A). To investigate how C5AR2 affects breast cancer cell proliferation, the researchers overexpressed C5AR2 in MDA-MB-231 cells and verified the success of C5AR2 overexpression in this cell line (Figure 1B). CCK8 assays revealed a significant increase in cell proliferation in C5AR2-overexpressing MDA-MB-231 cells (Figure 1C). Transwell assays revealed that C5AR2 overexpression also significantly enhanced the migration and invasion abilities of breast cancer cells (Figure 1D). Finally, Western blot analysis revealed that MMP2 and MMP9 levels were significantly upregulated in C5AR2-overexpressing MDA-MB-231 cells (Figure 1E), suggesting that C5AR2 is associated with the EMT of breast cancer. Furthermore, the relationship between C5AR2 and other key genes in breast cancer signaling pathways was analyzed using the TIMER database (Figure 1F). As shown in Figure 1G, C5AR2 expression levels showed a significant and strong positive correlation with MAPK3, STAT3, and NFKB1, and a moderate positive correlation with three other genes (PIK3CB, CTNNB1, and MTOR). Overall, C5AR2 promotes breast cancer cell proliferation, migration, and invasion, as well as the activation of oncogenic pathways.

Figure 1. Overexpression of C5AR2 facilitated the migration, invasion, and proliferation in breast cancer cells. (Zhu Y, et al., 2021)