6659

SOX4

BACKGROUND: The SOX4 transcription factor is involved in the development and cell fate decision. Although upregulation of SOX4 has been described in human prostate cancer (PCa), the prognostic value of SOX4 and its exact role in PCa progression remain unclear. METHODS: Three tissue microarrays were constructed from 241 Chinese PCa patients who underwent TURP. Immunohistochemistry (IHC) was used to detect the expression of SOX4. Genetic aberrations of epidermal growth factor receptor and HER2 were detected by fluorescence in situ hybridization. The effect of SOX4 on proliferation was evaluated by MTT (methyl thiazolyl tetrazelium), and cell migration and invasion were evaluated by transwell and wound-healing assays. The distribution of cell-cycle phase was analyzed by flow cytometry. Real-time PCR and western blot were used to study transcript and protein levels. RESULTS: Using tissue microarray, we found that SOX4 was overexpressed in 33.0% (76/230) Chinese PCa patients by IHC. SOX4 overexpression was significantly associated with high Gleason scores (P=0.009) and the presence of distant metastasis (P=0.023). Additionally, SOX4 overexpression was significantly correlated with high Ki67 labeling index (P=0.005) and tended to associate with amplification of HER2 (P=0.052) in our cohort. Notably, SOX4 was correlated with cancer-specific mortality of PCa patients by Kaplan-Meier analysis (P=0.001). Multivariate Cox regression analysis indicated that SOX4 was an unfavorable independent prognostic factor in Chinese PCas (P=0.017). SOX4 overexpression enhanced proliferation of Vcap cells and siRNA knockdown of SOX4 significantly decreased Vcap cell migration and invasion, suggesting a role of SOX4 in cancer metastasis. Additionally, flow cytometry DNA analysis revealed that siRNA SOX4 leads to significant accumulation of cells in the S phase and marked decrease of cells in the G2/M phase. Further in vitro study revealed that SOX4 silencing could inhibit TGF-beta (transforming growth factor-beta)-induced epithelial-mesenchymal transition (EMT) in Vcap cells. Overexpression of SOX4 could promote the EMT phenotype in Vcap cells. CONCLUSIONS: Our results define an important role for SOX4 in the progression of PCa by orchestrating EMT and may serve as a prognostic marker for PCa patients.

tumor metastasis is the leading cause of mortality and morbidity of prostate cancer (PCa) patients. epithelial-mesenchymal transition (EMT) plays a critical role in cancer progression and metastasis. Recent evidence suggested that diabetic patients treated with metformin have lower PCa risk and better prognosis. This study was aimed to investigate the effects of metformin on EMT in PCa cells and the possible microRNA (miRNA)-based mechanisms. MiRNAs have been shown to regulate various processes of cancer metastasis. We herein showed that metformin significantly inhibits proliferation of Vcap and PC-3 cells, induces G0/G1 cell cycle arrest and inhibits invasiveness and motility capacity of Vcap cells. Metformin could inhibit TGF-beta-induced EMT in Vcap cells, as manifested by inhibition of the increase of N-cadherin (p=0.013), Vimentin (p=0.002) and the decrease of E-cadherin (p=0.0023) and beta-catenin (p=0.034) at mRNA and protein levels. Notably, we demonstrated significant upregulation of miR30a levels by metformin (P<0.05) and further experiments indicated that miR30a significantly inhibits proliferation and EMT process of Vcap cells. Interestingly, we identified that SOX4, a previously reported oncogenic transcriptional factor and modulator of EMT, is a direct target gene of miR30a. Finally, we screened the expression of miR30a and SOX4 in 84 PCa cases with radical prostatectomy. Of note, SOX4 overexpression is significantly associated with decreased levels of miR30a in PCa cases. In all, our study suggested that inhibition of EMT by metformin in PCa cells may involve upregulation of miR30a and downregulation of SOX4.CI - Copyright (c) 2014 Elsevier Inc. All rights reserved.

Incomplete understanding remains in the molecular mechanisms underlying progression and metastasis of renal cancer. The transcription factor SOX4 is upregulated in various human malignancies, including renal cancer, indicating it may be involved in renal tumorigenesis. In this study, we explored this hypothesis by loss-of-function and gain-of-function assays of SOX4 in renal cancer cell lines and renal epithelial cell line. We found that specific knockdown of SOX4 in renal cancer cell lines significantly suppressed the migration and invasion of cancer cells; specific overexpression of SOX4 in renal epithelial cell line markedly promoted the migration and invasion of the cell line. epithelial-mesenchymal transition (EMT), a fundamental morphogenesis process, is implicated in renal cancer progression and metastasis. Our results demonstrated that SOX4 positively regulated the expression of mesenchymal cell markers and negatively regulated the expression of epithelial cell marker, and was involved in signal transduction pathway of TGFbeta-induced EMT. In addition, SOX4 induced EMT probably through modulating the AKT/p-AKT signaling cascade. Finally, we found that SOX4 was significantly upregulated in clinical renal cancer samples compared with corresponding normal tissues and associated with EMT process in clinical samples. Taken together, our findings confirm a crucial function of SOX4 in the metastasis of renal cancer through orchestrating EMT and establish that the function suppression of SOX4-AKT-EMT axis might be an attractive therapeutic intervention during renal cancer metastasis.

Increasing evidence has revealed that aberrant expression of miRNAs contributes to non-small cell lung cancer (NSCLC) development and progression. However, the roles and mechanisms of various miRNAs in NSCLC remain to be determined. In the present study, we confirmed that reduced miR-212 expression was present in NSCLC tissues and cell lines. Our clinical analysis revealed that the reduced miR-212 expression was significantly correlated with poor prognostic features including positive lymph node metastasis and advanced tumor-node-metastasis (TNM) stage. Moreover, we demonstrated that miR-212 is a novel independent prognostic marker for predicting 5-year survival of NSCLC patients. The ectopic overexpression of miR-212 inhibited cell migration, invasion and EMT, while downregulated miR-212 reversed the effect. In addition, miR-212 regulated SOX4 by directly binding to its 3'-untranslated region (3'-UTR), leading to suppression of EMT progression. In clinical samples of NSCLC, miR-212 was negatively correlated with SOX4, which was upregulated in NSCLC. Alteration in SOX4 expression reversed the functional effects of miR-212 in regards to migration, invasion and EMT in the NSCLC cells. In conclusion, our data indicated that miR-212 functions as a tumor-suppressor gene by regulating EMT and metastasis of NSCLC by targeting SOX4 signaling, and may represent a novel potential therapeutic target and prognostic marker for NSCLC.