Investigation of the effect of common chemotherapy drugs on the expression of PD-L1 and CD276 immune checkpoints in pancreatic cancer cell line

Abstract

Revealing the changes that occurred in the signaling pathways and immune elements of the tumor microenvironment in response to different types of chemotherapy regimens with or without radiotherapy may provide us valuable information that can help us choose more effective chemotherapy regimens that are in line with activation of the immune system against the tumor as much as possible and to guide the design of combination treatments with immunotherapy against specific immune targets such as immune checkpoints. The present study aims to investigate the effect of common chemotherapy drugs on the expression of immune checkpoints PD-L1 and CD276 in pancreatic cancer cell lines. Materials and Methods: First, the pancreatic cancer cell line named MIA-PACA-2 was cultured in RPMI 1640 culture medium enriched with 10% FBS at 37°C and 5% Co2, and then the expression level of PD-L1 and CD276 (B7-H3) genes were measured by qRT-PCR technique. Also, the proliferation rate of cancer cells was evaluated by the MTT method. Following the addition of common chemotherapy drugs in the treatment of pancreatic cancer such as 5-fluorouracil, oxaliplatin, and gemcitabine, and the passage of time, the primary culture medium is replaced with the culture medium containing MTT and after 4 hours of incubation And then adding culture medium containing DMSO and Sorensen phosphate buffer to the wells, the amount of light absorption at 570 nm wavelength was read by ELISA Plate Reader. Finally, the expression level of PD-L1 and CD276 (B7-H3) genes was again measured by qRT-PCR. Results: PD-L1 gene expression under the influence of gemcitabine and CD276 gene expression under the influence of 5-fluorouracil (5-FU) significantly downregulated (p<0.05). On the other hand, compared to the control group, gemcitabine led to an increase in CD276 expression and 5-FU led to a decrease in PD-L1 gene expression; While there is no statistically significant difference. Therefore, it can be concluded that the drug 5-FU has led to a decrease in the expression of both genes involved in the progression of the MIA-PACA-2 cancer cell line.