Effect of conditioned medium from miRNA-34a transfected gastric cancer-associated fibroblast on peripheral blood mononuclear cells.

BACKGROUND: Cancer-associated fibroblast (CAF) cells play an important role in gastric malignancy. MiRNA dysregulation has been detected in CAF cells, which is related to the tumor progression ability of these cells. Therefore, this study aimed to evaluate the function of miRNA34a in CAF cells in gastric carcinoma. METHOD: We transiently transfected miRNA-34a mimic in CAF cells and examined the effect of the overexpressed miRNA on PD-L1 expression using real-time PCR. Next, we evaluated the role of transfected CAF-conditioned medium (CM) on the immune response and viability of gastric cancer cell lines. RESULTS: We have shown that miRNA-34a significantly reduced PD-L1 expression in CAF cells (p < 0.05). However, the conditioned medium of transfected cells had no significant effect on the immune response. We also found that CM of miRNA-34a transfected CAF cells significantly suppressed gastric cancer cell line viability relative to the control group (P < 0.05). CONCLUSION: We indicated that CM of miRNA-34a transfected CAF can reduce gastric cancer cell line proliferation. Additionally, miRNA-34a in these cells may improve immune response via PD-L1 reduction. Thus, miRNA-34a could be a potential therapeutic agent in gastric cancer treatment. CLINICAL TRIAL NUMBER: Not applicable.