Association and functional role of CXCR4/CXCR7 and the NF-κB pathway in triple-negative breast cancer

Abstract:

Background and Aims Triple-negative breast cancer (TNBC) is highly aggressive and lacks effective targeted therapies. The chemokine receptors CXCR4 and CXCR7 are overexpressed in TNBC and may promote tumour cell migration and invasion by activating the NF-κB signalling pathway. This study aimed to investigate the roles of CXCR4/CXCR7 and the NF-κB pathway in regulating the migration and invasion of TNBC cells.Methods In the TNBC cell line MDA-MB-231, CRISPR/Cas9 technology was used to individually or in combination knock out the CXCR4 and CXCR7 genes. Additionally, a group treated with the NF-κB inhibitor BAY 11-7082 was established. The phosphorylation levels of IκB-α and p65 were assessed by Western blotting to evaluate NF-κB pathway activity. Cell proliferation, migration, and invasion were evaluated using the CCK-8 assay, wound healing assay, and Transwell assay, respectively.Results MDA-MB-231 cell lines with CXCR4, CXCR7, or dual gene knockout were successfully established. Western blot analysis revealed that the phosphorylation levels of IκB-α and p65 were significantly reduced in all knockout groups (all P<0.05), with the dual knockout group exhibiting a more substantial inhibitory effect than the single knockouts. However, BAY 11-7082 (5 μmol/L, 24 h) exerted a more pronounced suppression of IκB-α and p65 phosphorylation compared to the dual knockout group (all P<0.05). Functional assays demonstrated that both gene knockout and NF-κB inhibition significantly impaired the migration and invasion of TNBC cells (all P<0.05). Among all groups, the dual knockout of CXCR4 and CXCR7 showed greater inhibitory effects than either single knockout. At the same time, the BAY 11-7082 treatment exhibited the most potent suppression of both migration and invasion (both P<0.05).Conclusion CXCR4 and CXCR7 promote TNBC cell migration and invasion by activating the NF-κB signalling pathway, suggesting that the NF-κB pathway may serve as a potential therapeutic target for combination immunotherapy in TNBC.