IFN-γ激活ERK/Jak2-STAT信号通路诱导乳腺癌细胞过表达PD-L1和上皮-间质转化

IFN-γ induces overexpression of PD-L1 and epithelial- mesenchymal transformation of breast cancer cells through activating ERK/Jak2-STAT signaling pathways

摘要:

旨在探讨IFN-γ诱导乳腺癌细胞株MDA-MB-231表面程序性死亡配体 (PD-L1)的表达、对上皮间质转化的影响及其分子机制。用不同浓度IFN-γ作用MDA-MB-231细胞后，利用蛋白质免疫印迹检测PD-L1、细胞迁移相关蛋白 (E-钙黏蛋白、N-钙黏蛋白、波形蛋白)、ERK、p-ERK、Jak2及p-Jak2的表达水平；通过细胞划痕实验和Transwell实验检测细胞迁移能力；利用免疫荧光实验进一步检测细胞迁移相关蛋白的表达量。结果表明，IFN-γ可上调PD-L1的表达，使细胞划痕融合率显著增高，细胞迁移速率显著加快；波形蛋白和N-钙黏蛋白的表达量升高，E-钙黏蛋白表达量下降；ERK、p-ERK、Jak2及p-Jak2表达水平显著增加。加U0126后PD-L1、ERK及p-ERK表达水平下降，而加入AG490后，PD-L1、Jak2、p-Jak2表达水平下降。结果表明IFN-γ能上调乳腺癌细胞PD-L1表达水平，促进肿瘤细胞迁移，促使细胞从上皮向间质转化，而这一过程可能与ERK及Jak2-STAT信号通路相关。

Abstract:

To investigate the effect of INF-γ on the expression of programmed death ligand 1 (PD-L1), epithelial-mesenchymal transition (EMT) and the potential mechanism in breast cancer cell line MDA-MB-231, the cells were treated with different concentrations of INF-γ. The expressions of proteins, including PD-L1, cell-migration-related proteins (E-cadherin, N-cadherin and vimentin), ERK, p-ERK, Jak2, and p-Jak2 were detected by Western blotting analysis and immunofluorescent staining assay. Cell migration was studied through cell wound healing assay and transwell assay. IFN-γ could up-regulate the expressions of PD-L1 in MDA-MB-231 cells. The cell migration rate was significantly increased after adding IFN-γ. The expression levels of vimentin and N-cadherin were increased whereas the expression of E-cadherin was decreased after adding IFN-γ. The expression levels of ERK, p-ERK, Jak2 and p-Jak2 were significantly increased and this phenomenon was inhibited when adding ERK inhibitor U0126 or Jak2 inhibitor AG490. These results demonstrate that IFN-γ could up-regulate the expression of PD-L1, promote cell migration and transmission, and facilitate epithelial-mesenchymal transformation of breast cancer cells and this process may be related with ERK and Jak2-STAT signaling pathways.