| Background and objective: Based on the binary pattern classification of ovarian cancer: type I ovarian cancers were characterized by voluminous growth and relatively low progressive potential, of which low grade serous carcinoma and endometrial carcinoma are the most typical examples; type II ovarian cancer hold more aggressive features as compared, which include high grade serous carcinoma and endometrial carcinoma as examples. The role of tumor microenvironment in cancer invasiveness was recognized recently and cancer associated fibroblast(CAF) is the main component. Previously we isolated type I and type II CAFs from type I and II ovarian cancer tissues, which displayed the promotive effect upon tumor spreading differentially. But the underlying mechanism was unclear. HSF1, a kind of heat shock transcription factor, was reported to reprogram tumor stromal cells and promote the formation of malignant tumor. This study was designed to explore the role of HSF1 in activating CAFs and thus promoting ovarian cancer cell migration.Methods: 1. CAFs and tumor cells were isolated from two type ⅠEOC and five type Ⅱ EOC specimens and migration-promoting effect of type I/II CAFs to the primary ovarian cancer cells were tested individually. 2. Mice xenograft were made from ovarian cancer cell lines with different invasive potential. Tumors were removed and CAFs were extracted to verify the importance of cancer cell’s feature in recruiting stromal cells and activating CAFs for tumor metastasis.3 Immunohistochemical staining was performed to detect the expression of HSF1 in normal ovarian tissue(n=10) and ovarian cancer tissues(n=40) including type I 20 cases and type II 20 cases. Immunocytochemistry was used to test the expression of HSF1 between NFs and CAFs; 4. Western blot assessed the expression of HSF1 in ovarian cancer cell lines, NFs and CAFs. 5. Inducible CAFs(indCAFs) were established from NFs co-cultured with Hey conditional medium(CM), and HSF1 and α-SMA expression in NFs/ indCAFs/CAFs were detected by western blot and qRT-PCR, migration of indCAFs and Migration and invasion Hey cells co-cultured with CM from indCAFs were verified. 6.HSF1 and α-SMA expression in CAFs with HSF1 silenced were detected by western blot.migration and invasion of CAF-iHSF1 and Hey cells co-cultured with CM from CAF-i HSF1 were tested by traswell assay.Results: 1.CAFs from type II EOC presented with much greater promotive effect on tumor cells compared to those from type I EOC; 2.Xenograft tumor from SKOV3 and OVCAR3 cell lines displayed differential role in promoting EOC cells, and various stromal staining, HSF1 and α-SMA expression were also demonstrated.3.The immunohistochemical results showed the expression of HSF1 was higher expression in cancer cells and stromal cells of epithelial ovarian cancer tissue than in normal ovarian tissue(P<0.01); Immunocytochemistry showed HSF1 over expressed in CAFs than NFs.4.Expression of HSF1 in Type II EOC cells was higher than that of type I, and HSF1 expressed higher in primary CAFs than NFs.5. Inducible CAFs with high expression of HSF1 and α-SMA had a high migration and also obviously promoted the metastasis of EOC cells(P<0.01);.6.CAF-iHSF1 with a low HSF1 and α-SMAexpression receded the migration, invasion of fibroblasts and Hey cells.Conclusion: Higher HSF1 expression in EOC, its consistent expression in cancer cells with that in stroma, and its ability of activating CAFs, might support its role in helping cancer cells reprogramming stroma so as to promote the metastasis in return. |
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