Oral cancer-associated fibroblasts inhibit heat-induced apoptosis in Tca8113 cells through upregulated expression of Bcl-2 through the Mig/CXCR3 axis

The aim of this study was to detect oral cancer-associated fibroblast-secreted cytokines and their regulation of heat-induced apoptosis in the human tongue squamous cell carcinoma cell line Tca8113. We isolated cancer-associated fibroblasts (CAFs) from human tongue squamous cell carcinoma and normal fibroblasts (NFs) from normal oral mucosa. The expression profiles of cytokines secreted by CAFs and those secreted by NFs were detected using the RayBio (R) human cytokinc antibody microarray. The conditioned medium was prepared by mixing the CAF or NE supernatant cell culture medium with fresh complete medium. The expression levels of Bax, Bcl-2 and CXCR3 in Tca8113 cells were detected by western blot analysis. The heat-induced apoptosis ratio of the Tca8113 cells was detected by propidium iodide staining combined with flow cytometry. The quantity of the Mig factor, one of the chemokines secreted by CAFs, was clearly increased 19-fold when compared with the level in NFs. The conditioned medium of NFs had no obvious effect on the expression levels of Bax/Bcl-2 and the heat-induced apoptosis ratio in the Tca8113 cells. However, the expression levels of Bcl-2 were significantly upregulated and heat-induced Tca8113 cell apoptosis was inhibited in the CA F-conditioned medium. After adding neutralizing antibodies against Mig or its receptor CXCR3, the enhanced expression of the Bcl-2 protein and the inhibited heat-induced apoptosis of Tca8113 cells in the CAF-conditioned medium were significantly attenuated. CAFs may increase the expression levels of Bcl-2 through the paracrine secretion of Mig and reduce the thermosensitivity of Tca8113 cells.