Expression of hepaCAM inhibits bladder cancer cell proliferation via a Wnt/ß-catenin-dependent pathway in vitro and in vivo.

We previously established that hepatocyte cell adhesion molecule (hepaCAM), a typical structure of immunoglobulin (Ig)-like adhesion molecules, inhibited the proliferation and the progression of cultured human bladder cancer cells. As increasing evidence reveals that aberrant activation of canonical Wnt pathway is involved in the pathogenesis of bladder cancer, and ß-catenin serves as a pivotal molecule of Wnt pathway. Then, we explored whether the anti-proliferation effect of hepaCAM was associated with Wnt/ß-catenin pathway in human bladder cancer cells. The negative correlation between hepaCAM and ß-catenin in transitional cell carcinoma of bladder (TCCB) was found. Follow by, studied the effect of hepaCAM on the key elements of Wnt pathway. Here, Our researches showed that hepaCAM played a central role in modulating the Wnt/ß-catenin signaling pathway by interfering nuclear protein levels of ß-catenin, leading to down-regulate transcriptional activity of LEF/TCF and its target genes c-Myc and cyclinD1. Mechanistically, we demonstrated that hepaCAM-activated GSK3ß led to elevate the phosphorylation of ß-catenin, contributing to the aberrant translocation of ß-catenin. In addition, Anti-proliferation and associated molecular mechanisms of hepaCAM were demonstrated by using vivo experiment. In conclusion, our reports uncover that expression of hepaCAM suppresses the proliferation of bladder cancer cells through a Wnt/ß-catenin-dependent signaling pathway in vitro and in vivo.

[Influence of hepatocyte cell adhesion molecule on gene expression profile of human bladder transitional cell carcinoma cell line].

OBJECTIVE: To investigate the changes of gene expression file in transitional cell carcinoma of bladder after hepatocyte cell adhesion molecule(hepaCAM) overexpression. METHODS: Affymetrix Human Genome U133 Plus 2.0 Array was used to investigate the changes of gene expression profile between adenovirus-green fluorescent protein(GFP) -hepaCAM group and GFP group in transitional cell carcinoma of bladder EJ cells.Significant Analysis of Microarray(SAM) was used to screen the differentially expressed genes, DAVID software was used to conduct gene ontology analysis and wikiPathway analysis based on the differentially expressed genes. Reverse transcription-polymerase chain reaction and Western blot were applied to verify microarray data. RESULTS: Compared with the GFP group, a total of 2469 genes were up-regulated or down-regulated by more than 2 times in the GFP-hepaCAM group. Among these genes, 1602 genes were up-regulated and 867 were down-regulated.Most of the differentially expressed genes were involved in the function of cell proliferation and cell cycle regulation. The mRNA expressions of nibrin, liver kinase B1, and cyclin D1 detected by reverse transcription-polymerase chain reaction in three different bladder cancer cell lines were consistent with the microarray data.The protein expressions of nibrin and liver kinase B1 in these three cell lines measured by Western blot were consistent with the mRNA expression. CONCLUSIONS: HepaCAM can alter the gene expression profile of bladder cancer EJ cells. The well-known anti-tumor effect of hepaCAM may be mediated by regulating the gene expression via multiple pathways.