Targeting the CXCR7 pathway with TC14012 to inhibit endothelial necroptosis and lung cancer metastasis.

Endothelial necroptosis plays a crucial role in regulating cancer metastasis. Our previous research demonstrated that TC14012, which is an agonist of CXCR7, exhibits protective effects against endothelial injury. This study was designed to elucidate the effects of TC14012 on endothelial necroptosis and cancer lung metastasis, along with deciphering the underlying molecular mechanisms. The trans-well analysis system was used to evaluate the trans-endothelial migration ability of the tumor cells. Cell death was evaluated with Ethidium Homodimer 3 (EthD-3) staining and flow cytometry analysis. The expression and phosphorylation of MLKL or RIPK3 were evaluated using Western blot. The effects of TC14012 on cancer lung metastasis in vivo were determined using the mouse hematogenous metastasis model. The results showed that TC14012 treatment significantly suppressed trans-endothelial migration of lung cancer cells, through effectively counteracting endothelial cell death induced by the tumor cells in vitro. Upon inhibition of cell necroptosis with necrosulfonamide (NSA), an MLKL inhibitor, the suppressive effects of TC14012 on endothelial cell death were significantly alleviated. Further investigations unveiled that TC14012, via its interaction with CXCR7 receptor rather than CXCR4, impeded the phosphorylation and subsequent activation of the RIPK3/MLKL signaling cascade. Ultimately, in vivo experiments demonstrated that administration of TC14012 mitigated lung infiltration of pre-labeled tumor cells and reduced lung metastasis in mice subsequent to intravenous injection of tumor cells. In summary, TC14012 effectively retards lung cancer metastasis by inhibiting endothelial necroptosis and the consequential trans-endothelial migration of tumor cells, through modulating the CXCR7/RIPK3/MLKL signaling.