Investigation of the combined effect of immunotherapy with DCs pulsed with colorectal tumor cell lysates and CTLA-4 inhibitor on T cell response

Abstract

Regulating immune check points provides a breakthrough in cancer treatment, such as oral cancer therapy. CTLA-4, 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. In this study, we exmined the effect of CTLA-4 gene suppression on growth, apoptosis, and migration inhibition in HN-5 Oral squamous cell carcinoma cells. Materials and methods: In the current study, we evaluate the effect of CTLA-4 suppression on the HN-5 cells proliferation and survival by MTT assay. Flow cytometry was used to study the induction of apoptosis and the cell cycle arrest in CTLA-4 downregulated HN-5 cells. Wound healing assay used for determining the migration ability of Oral squamous cell carcinoma cells. For evaluating the expression level of apoptosis-related gene, qRT-PCR was preformed. Results: The expression of CTLA-4 gene decreased after transfecting specific siRNA in HN-5 cells. Inhibition of CTLA-4 led to the relative reduction of HN-5 cells proliferation. 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 CTLA-4 knockdown.