evaluating the effect of PD-L1 gene silencing on growth, migration and apoptosis in oral squamous carcinoma cell line

Abstract

Introduction: Oral squamous cell carcinoma is a serious and growing problem in many parts of the world. Regulating immune check points provides a breakthrough in cancer treatment, such as oral cancer therapy. PD-L1, a novel check point regulator, is a type I transmembrane proteine that negatively regulates the immune system. Blocking this novel immune check point can enhance the efficacy of cancer treatment. PD-L1 is an inhibitory immune check point that expresses in immune cells and tumor cells. Among all new therapies using small interfering RNA (siRNA) for silencing gene is a promising approach. Purpose: The aim of this study is to exmine the effect of PD-L1 gene suppression on growth, apoptosis, and migration inhibition in HN-5 Oral squamous cell carcinoma cells. Materials and method: In the current study, we evaluate the effect of suppression PD-L1 on the HN-5 cells proliferation and survival by MTT assay. Wound healing assay used for determining the migration ability of Oral squamous cell carcinoma cells after silencing PD-L1 gene. Flow cytometry was used to study the induction of apoptosis and the cell cycle arrest in PD-L1 downregulated HN-5 cells. For evaluating the expression level of apoptosis-related gene, qRT-PCR was preformed.

Results: The expression of PD-L1 gene decreased after transfecting specific siRNA in HN-5 cells. Inhibition of PD-L1 led to the relative reduction of HN-5 cells proliferatin. Further, flow cytometry results showed arrest in the G1 phase. The expression level of Bax increased, BCL-2 decreased, CAS9 increased and C-Myc decreased after PD-L1 knockdown. Conclusion: In Conclusion, the current study demonstrated that PD-L1 mediated pathways are involved in tumor development. Therefore, blocking PD-L1 may provide a novel immunotherapeutic approach for cancer treatment.