Tobacco extracts promote PD‐L1 expression and enhance malignant biological differences via mTOR in gefitinib‐resistant cell lines

BACKGROUND: The aim of this study was to investigate whether tobacco extracts could regulate PD‐L1 expression and enhance malignant biological differences in gefitinib‐resistant cell lines. METHODS: We constructed gefitinib‐resistant cells and observed the biological differences in gefitinib‐resistant cells. The cells were stimulated with medium containing 5% volume of tobacco extract, and the change in PD‐L1 expression and the mammalian target of rapamycin (mTOR) and p‐mTOR expression in gefitinib‐resistant cells treated with tobacco extracts was observed. We discussed the relationship between PD‐L1 and mTOR. RESULTS: Tobacco extracts could promote PD‐L1 expression in the cell line. Western blot analysis showed that mTOR and p‐mTOR were significantly enhanced in gefitinib‐resistant cell lines cultured in the tobacco extracts. The mTOR signaling pathway was involved in PD‐L1 expression and in regulating the expression of cytokines IL‐6 and IL‐23. In addition, the tobacco extracts could promote macrophage migration via mTOR/IL‐6. CONCLUSIONS: PD‐L1 can transmit inhibitory signals and reduce the proliferation of CD8 + T cells in lymph nodes. Tobacco extracts upregulate PD‐L1 expression via mTOR/IL‐6. These results imply that lung cancer patients should not smoke and stay away from a smoke environment.