Expression data from Chinese renal cell carcinoma cells with FSTL1 knocked down

Clear cell renal cell carcinoma (ccRCC), the major histotype of cancer derived from kidney, is lack of robust prognostic and/or predictive biomarker and powerful therapeutic target. We previously identified that follistatin-like protein 1 (FSTL1) was significantly down-regulated in ccRCC at the transcription level. In the present study, we characterized, for the first time, that FSTL1 immunostaining was selectively positive in the cytoplasm of distal convoluted tubules. The expression of FSTL1 was significantly lower in ccRCC tissues than in adjacent renal tissues (P<0.001), as measured using immunohistochemistry in 69 patients with paired specimens, and lower in most ccRCC cell lines than in human embryonic kidney cells, as measured by quantitative RT-PCR. Multivariate Cox regression analysis in 89 patients with follow-up data showed that FSTL1 expression in tumors conferred a favorable postoperative prognosis independently, with a hazard ratio of 0.325 (95% confidence interval: 0.118-0.894). FSTL1 knockdown promoted anchorage independent growth, mobility, and invasion of ccRCC cell lines and promoted cell cycle from G0/G1 phases into S phase; while over-expression of FSTL1 significantly attenuated cell migration ability in ACHN cells. FSTL1 knockdown resulted in decreased expression of E-cadherin and increased expression of N-cadherin in ccRCC cell lines significantly, indicating that FSTL1 may attenuate epithelial to mesenchymal transition in ccRCC. Microarray assay indicated that NF-B and HIF-2 pathways were activated following FSTL1 knockdown in ccRCC cells. Our study indicates that FSTL1 serves as a tumor suppressor in ccRCC, up-regulation of FSTL1 in cancer cells may be a candidate target therapy for advanced ccRCC.

3

Liu Y, Tan X, Liu W, Chen X, Hou X, Shen D, Ding Y, Yin J, Wang L, Zhang H, Yu Y, Hou J, Thompson TC, Cao G