SNAI1 is critical for the aggressiveness of prostate cancer cells with low E-cadherin

Molecular Cancer

Research

Harold Ting¹  Kavitha C Vijendra¹  Anil K Jain¹  Subhash C Gangar¹  Anand Ramteke²  Gagan Deep³  Chapla Agarwal³  Rajesh Agarwal³ 

[1] Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, San Diego, USA;Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, San Diego, USA;Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, India;Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, San Diego, USA;University of Colorado Cancer Center, University of Colorado Denver, Aurora, Colorado, USA;

关键词: Prostate cancer;    E-cadherin;    SNAI1;    Stemness;    EMT;   

DOI  :  10.1186/1476-4598-13-37

 received in 2013-09-25, accepted in 2014-02-21,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundA better molecular understanding of prostate carcinogenesis is warranted to devise novel targeted preventive and therapeutic strategies against prostate cancer (PCA), a major cause of mortality among men. Here, we examined the role of two epithelial-to-mesenchymal transition (EMT) regulators, the adherens junction protein E-cadherin and its transcriptional repressor SNAI1, in regulating the aggressiveness of PCA cells.MethodsThe growth rate of human prostate carcinoma PC3 cells with stable knock-down of E-cadherin (ShEC-PC3) and respective control cells (Sh-PC3) was compared in MTT and clonogenic assays in cell culture and in nude mouse xenograft model in vivo. Stemness of ShEC-PC3 and Sh-PC3 cells was analyzed in prostasphere assay. Western blotting and immunohistochemistry (IHC) were used to study protein expression changes following E-cadherin and SNAI1 knock-down. Small interfering RNA (siRNA) technique was employed to knock- down SNAI1 protein expression in ShEC-PC3 cells.ResultsShEC-PC3 cells exerted higher proliferation rate both in cell culture and in athymic nude mice compared to Sh-PC3 cells. ShEC-PC3 cells also formed larger and a significantly higher number of prostaspheres suggesting an increase in the stem cell-like population with E-cadherin knock-down. Also, ShEC-PC3 prostaspheres disintegration, in the presence of serum and attachment, generated a bigger mass of proliferating cells as compared to Sh-PC3 prostaspheres. Immunoblotting/IHC analyses showed that E-cadherin knock-down increases the expression of regulators/biomarkers for stemness (CD44, cleaved Notch1 and Egr-1) and EMT (Vimentin, pSrc-tyr416, Integrin β3, β-catenin, and NF-κB) in cell culture and xenograft tissues. The expression of several bone metastasis related molecules namely CXCR4, uPA, RANKL and RunX2 was also increased in ShEC-PC3 cells. Importantly, we observed a remarkable increase in SNAI1 expression in cytoplasmic and nuclear fractions, prostaspheres and xenograft tissues of ShEC-PC3 cells. Furthermore, SNAI1 knock-down by specific siRNA strongly inhibited the prostasphere formation, clonogenicity and invasiveness, and decreased the level of pSrc-tyr416, total Src and CD44 in ShEC-PC3 cells. Characterization of RWPE-1, WPE1-NA22, WPE1-NB14 and DU-145 cells further confirmed that low E-cadherin is associated with higher SNAI1 expression and prostasphere formation.ConclusionsTogether, these results suggest that E-cadherin loss promotes SNAI1 expression that controls the aggressiveness of PCA cells.

【 授权许可】

CC BY   
© Deep et al.; licensee BioMed Central Ltd. 2014