Background
Although programmed cell death-ligand 1 (PD-L1) plays a well-known function in immune checkpoint response by interacting with programmed cell death-1 (PD-1), the cell-intrinsic role of PD-L1 in tumors is still unclear. Here, we explored the molecular regulatory mechanism of PD-L1 in the progression and metastasis of ovarian cancer.
Conclusion
Our results demonstrated that PD-L1 promoted the angiogenesis and metastasis of ovarian cancer by participating in the c-JUN/VEGFR2 signaling axis, suggesting that the combination of PD-L1 inhibitor and antiangiogenic drugs may be considered as a potential therapeutic approach for ovarian cancer patients.
Methods
Immunohistochemistry of benign tissues and ovarian cancer samples was performed, followed by migration, invasion, and angiogenesis assays in PD-L1-knockdown ovarian cancer cells. Immunoprecipitation, mass spectrometry, and chromatin immunoprecipitation were conducted along with zebrafish and mouse experiments to explore the specific functions and mechanisms of PD-L1 in ovarian cancer.
Results
Our results showed that PD-L1 induced angiogenesis, which further promoted cell migration and invasion in vitro and in vivo of ovarian cancer. Mechanistically, PD-L1 was identified to directly interact with vascular endothelial growth factor receptor-2 (VEGFR2) and then activated the FAK/AKT pathway, which further induced angiogenesis and tumor progression, leading to poor prognosis of ovarian cancer patients. Meanwhile, PD-L1 was found to be regulated by the oncogenic transcription factor c-JUN at the transcriptional level, which enhanced the expression of PD-L1 in ovarian cancer. Furthermore, we demonstrated that PD-L1 inhibitor durvalumab, combined with the antiangiogenic drug, apatinib, could enhance the effect of anti-angiogenesis and the inhibition of cell migration and invasion.