Effect and mechanism of ginsenoside Rg3 on inhibition of LLC proliferation in non-small cell lung cancer cells by immune checkpoint PD-L1 / 中草药

ABSTRACT

Objective To investigate the effect of ginsenoside Rg3 on immune checkpoint PD-L1 in Lewis cells (LLC) and to explore the related mechanism. Methods The effects of ginsenoside Rg3 on the proliferation of LLC were observed by MTT assay and cell long-term dynamic monitoring. LLC cells treated with 20 ng/mL IFN-γ were used to construct experimental model with high expression of PD-L1 in vitro. The effect of ginsenoside Rg3 on expression of PD-L1 was detected by flow cytometry and immunofluorescence. The effect of ginsenoside Rg3 on the protein expression of PI3K/Akt/mTOR pathway was verified by Western blotting. Results Ginsenoside Rg3 at 16, 32, 64, and 128 μmol/L significantly inhibited the proliferation of LLC (P < 0.01) and reduced the expression of PD-L1 induced by IFN-γ (P < 0.05). Ginsenoside Rg3 at 32 and 64 μmol/L significantly decreased the protein expression of PI3K and mTOR (P < 0.01), and ginsenoside Rg3 at 16, 32, and 64 μmol/L significantly inhibited the phosphorylation of Akt proteins (P < 0.05). Conclusion Ginsenoside Rg3 significantly inhibited the expression of PD-L1 in LLC cells by inhibiting PI3K/Akt/mTOR pathway. Ginsenoside Rg3 blocked the tumor cells escaping immune response by PD-L1 over-expression, enhanced the immune response of T cells, and inhibited the growth of non-small cell lung cancer cells.