Abstract;-Catenin is a cell adhesion molecule and a candidate mediator of Wnt signal transduction. We hypothesized that impaired regulation of ;-catenin through genetic and epigenetic pathways is associated with the pathogenesis of prostate cancer. To test this hypothesis, cytosine-phosphate-guanine methylation, loss of heterozygosity (LOH), and mutation status of the g g-catenin gene were analyzed in cultured prostate cancer cell lines, 180 localized prostate cancers, 69 benign prostatic hyperplasias, and 11 hormone refractory prostate cancers (HRPC). In prostate cancer cell lines (DuPro, LNCaP, ND-1, and PC3), g g-catenin mRNA transcripts were increased after 5-aza-2V-deoxycytidine treatment. In localized prostate cancer, ;-catenin expression was lower but prevalence of g g-catenin methylation was higher compared with benign prostatic hyperplasia. However, g g-catenin methylation did not correlate with Gleason sum, pT category, or capsular penetration. Among localized prostate cancers with positive g g-catenin methylation, the presence of LOH at chromosome 17q21 was closely related to down-regulation of g g-catenin mRNA expression. The g g-catenin mutations were not found in localized prostate cancers, whereas six mutations were found in five HRPCs within or close to the GSK-3B consensus motif phosphorylation site, among which four HRPCs showed strong nuclear ;-catenin accumulation. In these four HRPCs, Bcl-2 expression was increased, whereas the target of the Wnt signal, c-myc, was only expressed in one HRPC. Therefore, although epigenetic g g-catenin methylation is an early event in the development of prostate cancer, simultaneous events of epigenetic cytosine-phosphate-guanine methylation and genetic LOH may be responsible for functional loss of ;-catenin. The g g-catenin mutation related to Bcl-2 overexpression has a significant effect on the pathogenesis of HRPC. This is the first report to characterize the epigenetic and genetic regulation of ;-catenin in human prostate cancer. (Cancer Res 2005; 65(6): 2130-8)

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Heparanase plays a critical role in the degradation of extracellular matrix and cell membrane and is frequently upregulated in malignant tumors. Transcription factor, early growth response 1 (EGR1), is closely associated with inducible transcription of the heparanase gene. We hypothesized that promoter CpG hypomethylation with increased EGR1 expression could determine heparanase expression during the pathogenesis of bladder cancer. Bladder cancer cell lines (J82, T24 and transitional cell carcinoma) significantly restored heparanase expression after 5-AzadC treatment. Transfection of EGR1 siRNA with T24 bladder cancer cell line significantly downregulated heparanase expression compared to the control siRNA transfection. In 54 bladder cancer and paired normal bladder samples, heparanase expression was significantly higher in bladder cancer than in normal bladder (Po0.01). We performed methylation-specific PCR targeting the CpG sites within the core-binding consensus motifs of EGR1 (GGCG) and Sp1 (GGGCGG). Methylation prevalence was significantly higher in normal bladder than in bladder cancer (Po0.05) and inversely correlated with heparanase expression (P ¼ 0.055). In the total series of bladder cancer and normal bladder samples, the combination of promoter CpG methylation and EGR1 expression regulated heparanase expression in a stepwise manner, where heparanase expression was the lowest in methylation-positive and EGR1-negative samples and the highest in methylation-negative and EGR1-positive samples. To our knowledge, this is the first study demonstrating that increased heparanase expression during the pathogenesis of bladder cancer is due to promoter hypomethylation and transcription factor EGR1.