Chemotherapeutic Agents Increase PD-L1 Expression in A549 Lung Cancer Cell Line

Abstract Introduction: With the highest mortality rate, lung cancer is one of the most prevalent malignancies worldwide. Increasing PD-L1 expression is one of the mechanisms of ineffective anti-tumor response and immune evasion, which causes poor prognosis and survival rate. Chemotherapy has its own limitations such as drug resistance and the escape of cancer cells from the immune system. The current research aimed to assess the effects of common chemotherapy agents used in lung cancer on PD-L1 expression in tumor cells in order to help for selecting appropriate treatment regimens to increase patient survival. Methods First, A549 cells were cultured, and the expression of PD-L1 on this cell line was measured by qRT-PCR. Then, the viability of cancer cells was examined by MTT test. PD-L1 gene expression was measured by qRT-PCR in A549 cell line, after treatment with chemotherapy agents. Results PD-L1 gene expression was increased after 24 and 48 hours after treatment with cisplatin, docetaxel, paclitaxel and carboplatin. The IC50 of the mentioned drugs 24 hours after treatment were evaluated 27, 38.79, 18.66, and 54.17 µg/ml respectively. Conclusion The current study shows that PD-L1 expression increases in response to carboplatin, docetaxel, cisplatin, and paclitaxel in A549 cell line. This indicates that chemotherapy agents cause immune evasion by increasing PD-L1 expression on cancer cells, which makes these cells resistant to the immune system. The results also showed that carboplatin, docetaxel, cisplatin, and paclitaxel at 48 hours after treatment had a greater effect on increasing PD-L1 expression than 24 hours after treatment.