Background and purpose: Cancer-associated fibroblasts (CAFs) are known to promote the invasion and metastasis of epithelial cancers. The cytokine IL-6 may mediate the interaction between stromal cells and epithelia in tumor microenvironment to facilitate the invasiveness and metastasis of cancer

however

such mechanism has not been fully covered yet. Methods: We used cervical cancer cell line HeLa as a model for this study. ELISA was used to measure the levels of IL-6 in CAFs and normal fibroblasts (NFs) isolated from squamous cervical cancer or normal cervical tissues. CAFs conditioned medium or IL-6 was used to treat cervical cancer HeLa cell line. The epithelial-mesenchymal transition (EMT) markers such as N-Cadherin and Vimentin were detected by Western blot in cells before and after treatment. Scratches and transwell chambers were used to test the abilities of cell migration and invasion. Results: The levels of IL-6 were 4-5 folds higher in CAFs than in NFs. Treatment of HeLa cells with CAF conditioned medium or IL-6 upregulated N-Cadherin and Vimentin

but down-regulated E-Cadherin and cytokeratin

compared with control cells

indicating that IL-6 may stimulate HeLa cells to EMT. Further study found that Snail 1

the featured transcription factor for stem cells

was increased along with the enhanced phosphorylation of STAT3. Meanwhile

the migration and invasion of HeLa cells treated with IL-6 or CAF conditioned medium were markedly increased. Conclusion: CAF induces the EMT of cervical epithelial cancer cells through IL-6/STAT3/Snail pathway

which thereby promotes the invasiveness and metastasis cervical epithelial cancer.