Anticancer Efficacy of Nonthermal Plasma Therapy Combined with PD-L1 Antibody Conjugated Gold Nanoparticles on Oral Squamous Cell Carcinoma

Combination therapies for the treatment of oral squamous cell carcinoma have been studied extensively and represent a synergistic approach with better outcomes than monotherapy. In this study, a novel combination therapy was investigated using gold nanoparticles (GNP) conjugated to programmed cell death protein ligand 1 (PD-L1) antibodies and nonthermal plasma (NTP). The present study describes the effectiveness of NTP using PD-L1 antibody conjugated to GNP in PD-L1 expressing SCC-25 cells, an oral squamous cell carcinoma line. Immunocytochemistry revealed higher levels of PD-L1 expression and an increase in the selective uptake of PD-L1 antibody + GNP on SCC-25 cells compared to HaCaT cells. In addition, cell viability analyses confirmed higher levels of cell death of SCC-25 cells after treatment with PD-L1 antibody, GNP, and NTP compared to HaCaT cells. Among the experimental groups, the highest cell death was observed upon treatment with PD-L1 antibody + GNP + NTP. Following the Western blot analysis and immunofluorescence staining, the expression of apoptosis-related proteins was found to increase after treatment with PD-L1 antibody + GNP + NTP among the other experimental groups. In conclusion, the treatment of SCC-25 cells with PD-L1 antibody + GNP + NTP significantly increased the number of dead cells compared to other experimental groups. The results of this in vitro study confirmed the therapeutic effects of PD-L1 antibody + GNP + NTP treatment on oral squamous cell carcinoma.