Biomedical subjects

Rajvir Dahiya

Publications and source records attributed to Rajvir Dahiya.

At least 19 recordsLinked to original sources

PubMed2007

Functional improvement in spinal cord injury-induced neurogenic bladder by bladder augmentation using bladder acellular matrix graft in the rat.

Spinal cord injury (SCI) rostral to the lumbosacral level causes bladder hyperreflexia and detrusor-sphincter dyssynergia (DSD), which are accompanied by bladder hypertrophy. We hypothesize that bladder augmentation using a bladder acellular matrix graft (BAMG) can improve the function of SCI-mediated neurogenic bladder. In female rats (n = 35), SCI was induced by transection of the spinal cord at the lower thoracic level. Eight weeks following spinalization, bladder augmentation using BAMG was performed after hemicystectomy of the hypertrophic bladder. Cystometrography was performed at 8 weeks after spinalization and again at 8 weeks after augmentation. Several urodynamic parameters were measured and the grafted bladder was histologically evaluated. Thirty one rats were alive 8 weeks after spinalization. Twenty two (71%) rats developed hyperreflexic bladders and nine (29%) rats had underactive bladders before bladder augmentation. Twenty six rats survived until 8 weeks after augmentation. Urodynamic parameters showed improvement in some bladder functions in both hyperreflexic and underactive bladders after augmentation. In addition, bladder compliance was increased in hyperreflexic bladders and decreased in underactive bladders. Bladder augmentation decreased bladder capacity in high-capacity rats and increased it in low-capacity rats. Histological evaluation showed complete regeneration of BAMG in SCI-induced neurogenic bladder at 8 weeks after augmentation. This is the first report suggesting that the voiding function in SCI-induced neurogenic bladder can be improved by augmentation using BAMG. Improved voiding function was accompanied by histological regeneration of BAMG.

Animals↗

PubMed2007

Polymorphisms of catechol-O-methyltransferase in men with renal cell cancer.

The estrogen metabolite, 4-hydroxy-estrogen, has been shown to play a role in malignant transformation of male kidneys. To counteract the effects of this catechol-estrogen, the catechol-O-methyltransferase (COMT) enzyme is capable of neutralizing the genotoxic effects of this compound. A polymorphic variant of COMT has been shown to have a reduced enzyme activity, and thus, we hypothesize that single nucleotide polymorphisms of the COMT gene can be a risk factor for renal cell cancer (RCC). To determine this hypothesis, a study of a Japanese male population was used and the genetic distributions of COMT polymorphisms at codons 62 (C-->T), 72 (G-->T), and 158 (G-->A) were analyzed in 157 normal healthy subjects and 123 sporadic RCC (clear cell type) samples by using a sequence-specific PCR technique. These experiments show that the variant genotype (P = 0.025) and allele (P = 0.011) at codon 62 is a risk factor for RCC. The odds ratio and 95% confidence interval for cancer were 3.16 and 1.29 to 7.73, respectively, for the T/T genotype as compared with wild-type. No associations for renal cancer were found at either codons 72 or 158 in this Japanese male population. However, codons 62 and 158 were observed to be in linkage disequilibrium, and haplotype analysis shows the combined forms of T-A, T-G, and C-A to be associated with RCC as compared with C-G (P < 0.001). When evaluating the risk of COMT polymorphisms with grade of cancer, no associations were observed for any of the genotypes. This study is the first to report COMT polymorphism to be associated with RCC. These results are important in understanding the role of COMT polymorphisms in the pathogenesis of RCC.

Alleles↗

PubMed2006

Polymorphisms of DNA repair genes are risk factors for prostate cancer.

DNA repair gene alterations have been shown to cause a reduction in DNA repair capacity. We hypothesised that DNA repair gene polymorphisms may be risk factors for prostate cancer (PC). To test this hypothesis, DNA samples from 165 cases of prostate cancer and healthy controls were analyzed by PCR-RFLP to determine the genotypic frequency of three DNA repair genes (XRCC1, XPC and XRCC7). We found that the frequency of 939Gln variant at XPC Lys939Gln was significantly lower in PC cases (OR=0.39, P=0.016). Haplotype analysis of XRCC1 Arg194Trp (C/T) and Arg399Gln (G/A) revealed that the frequency of the T-A haplotype was significantly higher in PC patients. This is the first report on the studies of XPC and XRCC1 Arg194Trp polymorphisms in PC, and our present data suggest that XPC Lys939Gln and the T-A haplotype of XRCC1 Arg194Trp and Arg399Gln may be risk factors for PC in Japanese.

Aged↗

PubMed2006

Wnt antagonist family genes as biomarkers for diagnosis, staging, and prognosis of renal cell carcinoma using tumor and serum DNA.

PURPOSE: We hypothesized that combined methylation analysis of Wnt antagonist genes could serve as a panel of biomarkers for diagnosis, staging, and prognosis in renal cell carcinoma (RCC). EXPERIMENTAL DESIGN: Samples (n = 62) of RCC and corresponding normal renal tissue (NRT) were analyzed using methylation-specific PCR for methylation of six Wnt antagonist genes (sFRP-1, sFRP-2, sFRP-4, sFRP-5, Wif-1, and Dkk-3). To increase the sensitivity/specificity of RCC detection, the methylation score (M score) for multigene methylation analysis was developed. Receiver operator characteristic curve analysis was used to determine the optimal sensitivity/specificity of the M score. In addition, the M score was compared with the clinicopathologic outcome. Thirty-three serum DNA samples were also used to investigate the methylation status of Wnt antagonist genes. RESULTS: The methylation levels of all Wnt antagonists were significantly higher in RCC than in NRT. In multivariate regression analysis, the methylation level of sFRP-1 was a significant independent predictor of RCC, whereas for sFRP-2 and sFRP-4 there was a trend toward significance as independent predictors. The M score of Wnt antagonist genes was significantly higher in RCC than in NRT. Overall, the M score had a sensitivity of 79.0% and a specificity of 75.8% (area under the curve, 0.808) as a diagnostic biomarker. In addition, the M score could significantly distinguish grade, pT category, M category, and overall survival of RCC patients. The M score was independent of age and gender in predicting overall survival by the Cox proportional hazards model. In RCC patients, 72.7% of the methylation-specific PCR results had identical methylation in samples of tumor and serum DNA. No serum DNA in normal controls showed aberrant methylation of the Wnt antagonist genes. In addition, the methylation status of Wnt antagonist genes in serum DNA was significantly correlated with tumor grade and stage. CONCLUSIONS: This is the first report showing that M score analysis of Wnt antagonist genes can serve as an excellent epigenetic biomarker panel for detection, staging, and prognosis of RCC using serum DNA.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Small dsRNAs induce transcriptional activation in human cells.

Recent studies have shown that small noncoding RNAs, such as microRNAs and siRNAs, regulate gene expression at multiple levels including chromatin architecture, transcription, RNA editing, RNA stability, and translation. Each form of RNA-dependent regulation has been generally found to silence homologous sequences and collectively called RNAi. To further study the regulatory role of small RNAs at the transcriptional level, we designed and synthesized 21-nt dsRNAs targeting selected promoter regions of human genes E-cadherin, p21(WAF1/CIP1) (p21), and VEGF. Surprisingly, transfection of these dsRNAs into human cell lines caused long-lasting and sequence-specific induction of targeted genes. dsRNA mutation studies reveal that the 5' end of the antisense strand, or "seed" sequence, is critical for activity. Mechanistically, the dsRNA-induced gene activation requires the Argonaute 2 (Ago2) protein and is associated with a loss of lysine-9 methylation on histone 3 at dsRNA-target sites. In conclusion, we have identified several dsRNAs that activate gene expression by targeting noncoding regulatory regions in gene promoters. These findings reveal a more diverse role for small RNA molecules in the regulation of gene expression than previously recognized and identify a potential therapeutic use for dsRNA in targeted gene activation.

Argonaute Proteins↗

PubMed2006

Epigenetic inactivation of the dioxin-responsive cytochrome P4501A1 gene in human prostate cancer.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD; dioxin) is a toxic environmental contaminant that works through dioxin response elements (DRE) to activate gene expression. We tested the hypothesis that cancer-related epigenetic changes suppress dioxin activation of the cytochrome P4501A1 (CYP1A1) gene. 5-Aza-2'-deoxycytidine (5-aza-CdR), an inhibitor of DNA methylation, increases TCDD-inducible CYP1A1 mRNA expression in cancerous LNCaP cells but not in noncancerous PWR-1E and RWPE-1 cells (all human prostate cell lines). Bisulfite DNA sequencing shows that the TCDD-responsive CYP1A1 enhancer is highly methylated in LNCaP cells but not in RWPE-1 cells. In vivo footprinting experiments reveal that unmethylated DRE sites do not bind protein in response to TCDD in LNCaP cells, whereas inducible DRE occupancy occurs in RWPE-1 cells. Pretreatment of LNCaP cells with 5-aza-CdR partially restores TCDD-inducible DRE occupancy, showing that DNA methylation indirectly suppresses DRE occupancy. Chromatin immunoprecipitation experiments reveal that LNCaP cells lack trimethyl histone H3 lysine 4, a mark of active genes, on the CYP1A1 regulatory region, whereas this histone modification is prevalent in PWR-1E and RWPE-1 cells. We also analyzed CYP1A1 enhancer methylation in human prostate tissue DNA. We do not detect CYP1A1 enhancer methylation in 30 DNA samples isolated from noncancerous prostate tissue. In contrast, 11 of 30 prostate tumor DNA samples have detectable CYP1A1 enhancer methylation, indicating that it is hypermethylated in prostate tumors. This is the first report that shows that CYP1A1 is aberrantly hypermethylated in human prostate cancer and has an altered, inaccessible chromatin structure that suppresses its dioxin responsiveness.

Azacitidine↗

PubMed2006

Combination analysis of hypermethylated Wnt-antagonist family genes as a novel epigenetic biomarker panel for bladder cancer detection.

PURPOSE: Aberrant promoter hypermethylation of Wnt-antagonist genes contributes to the pathogenesis of several cancers. We hypothesized that combined methylation analysis of Wnt-antagonist genes could improve their use as a panel of biomarkers for diagnosing and staging of bladder cancers. EXPERIMENTAL DESIGN: Samples (54 total) of bladder tumor and corresponding normal bladder mucosa were analyzed for the methylation and expression levels of six Wnt-antagonist genes (sFRP-1, sFRP-2, sFRP-4, and sFRP-5, Wif-1, and Dkk-3). To increase the sensitivity/specificity of bladder tumor detection, the methylation score (M score), a new method for multigene methylation analysis, was developed. The M score of each sample was calculated as the sum of the corresponding log hazard ratio coefficients derived from multivariate logistic regression analysis of the methylation status for each Wnt-antagonist gene. Receiver operator characteristic (ROC) curve analysis was used to determine the optimal sensitivity/specificity of the M score. Urine DNA from 24 matched patients with bladder tumor and 20 cancer-free volunteers was also used to investigate the methylation status of Wnt-antagonist genes. RESULTS: The methylation levels of Wnt-antagonists were significantly higher and mRNA levels were significantly lower in bladder tumor than in bladder mucosa. Each methylation level was inversely correlated with the corresponding mRNA level. In multivariate regression analysis, the methylation levels of sFRP-2 and Dkk-3 were significant independent predictors of bladder tumor (P < 0.05 and P < 0.01, respectively), whereas with sFRP-1, sFRP-5, and Wif-1 there was a trend towards significance as independent predictors. The M score of Wnt-antagonist genes was significantly higher in bladder tumor than in bladder mucosa (P < 0.05). Overall, the M score had a sensitivity of 77.2% and a specificity of 66.7% as a diagnostic biomarker (areas under the curve, 0.763). The M score could distinguish superficial from invasive bladder tumors with a sensitivity of 72.2% and a specificity of 61.1% as a staging biomarker (areas under the curve, 0.671). In patients with bladder tumor, 80.6% of the methylation-specific PCR results had identical methylation in samples of tumor- and urine-derived DNA. Most urine DNA in normal controls showed no aberrant methylation of the Wnt-antagonist genes. CONCLUSIONS: Hypermethylation of Wnt-antagonist genes plays an important role in the pathogenesis of bladder tumor and can be detected using cellular DNA extracted from urine samples. This is the first report demonstrating that M score analysis of Wnt-antagonist genes could serve as an excellent epigenetic biomarker panel for bladder tumors.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Polymorphisms of DNA repair genes are associated with renal cell carcinoma.

DNA repair gene alterations have been shown to cause a reduction in DNA repair capacity and may influence an individual's susceptibility to carcinogenesis. Single nucleotide polymorphisms (SNPs) of DNA repair genes have been shown to cause a reduction in repair activity. We hypothesized that SNPs of DNA repair genes may be a risk factor for renal cell carcinoma (RCC). To test this hypothesis, DNA samples from 112 cases of renal cell cancer and healthy controls (n=180) were analyzed by PCR-RFLP to determine the genotypic frequency of six different polymorphic loci on five DNA repair genes (XRCC1, XPC, ERCC1, XRCC3, and XRCC7). The chi(2) test was applied to compare the genotype frequency between patients and controls. We found that the frequency of 399Gln variant at XRCC1 Arg399Gln was significantly higher in RCC cases than in controls (OR=2.83, 95%CI=1.24-6.49, P=0.01). The frequency of T-A haplotype of XRCC1 194 Trp and XRCC1 399Gln was significantly higher in RCC than controls. No differences in genotypes were observed at the other sites. This is the first report on SNPs of DNA repair genes in renal cell carcinoma that suggests XRCC1 399Gln polymorphism may be a risk factor for RCC. Our present data suggest that the XRCC1 399Gln allele may be linked to susceptibility for RCC.

Adult↗

PubMed2006

Collagen I:III ratio in canine heterologous bladder acellular matrix grafts.

The objective of this study was to investigate the limitations of a heterologous bladder acellular matrix graft (BAMG) and the influence of the collagen ratio on functional regeneration in a large animal model. Ten female dogs underwent partial cystectomy; eight received BAMG (two homologous; six heterologous) and two partial cystectomy only. A cystometry was performed prior to surgery and 7 months postoperatively when all animals underwent sacral root stimulation. Tissue specimens were studied by histologic and immunohistochemical techniques and for collagen types. At month 7, all animals survived and bladder capacity in the grafted animals was increased. All grafts demonstrated all components of a normal bladder wall. Nerves were seen with the density decreasing with distance from the anastomosis. The BAMG processing and follow-up demonstrated no changes in the homologous tissue, whereas in the heterologous tissue, the amount of collagen changed with the processing during implantation. None of these heterologous specimens demonstrated a similar collagen ratio to the hosts'. The homologous BAMG undergoes more complete regeneration. In the heterologous BAMG, collagen seems not to be replaced. The amounts and ratio of collagen types I and III seem to influence smooth muscle regeneration.

Animals↗

PubMed2006

Vascular endothelial growth factor restores erectile function through modulation of the insulin-like growth factor system and sex hormone receptors in diabetic rat.

Previous studies have shown that intracavernous injection of vascular endothelial growth factor (VEGF) restored erectile function in diabetic rats. However, the mechanism of VEGF in diabetes-related erectile dysfunction (ED) has not been fully investigated. We hypothesize that intracavernous injection of VEGF may reverse diabetes-related ED through modulation of the insulin-like growth factor system and sex hormone receptors. To test this hypothesis the erectile function of treated and control rats was analyzed by measurement of intracavernous pressure (ICP) following electrostimulation of the cavernous nerves. Mean ICP was significantly lower in non-treated diabetic rats compared to controls. After VEGF injection, ICP was significantly higher than in non-treated diabetic rats. IGFBP-3 mRNA and protein expression was significantly higher in non-treated diabetic rat crura than controls, while VEGF-treated animals had control levels. ER-beta and PR mRNA and protein expression was significantly lower in non-treated diabetic rat crura. After VEGF injection, ER-beta and PR mRNA and protein expression was similar to control levels. Expression of AR and ER-alpha was the same in all groups. These findings suggest that orthotopic injection of VEGF may improve the functional recovery of diabetes-related ED through modulation of the insulin-like growth factor system and sex hormone receptors. To our knowledge, this is the first study demonstrating that VEGF treatment restores erectile function through restoration of the insulin-like growth factor system and sex hormone receptor genes at the mRNA and protein levels in diabetic rat crura. These results may be important in understanding the pathogenesis of diabetes-related ED and also in providing better strategies for management of this disease.

Animals↗

PubMed2006

Epigenetic inactivation of Wnt inhibitory factor-1 plays an important role in bladder cancer through aberrant canonical Wnt/beta-catenin signaling pathway.

PURPOSE: Aberrant activation of the Wingless-type (Wnt) pathway plays a significant role in the pathogenesis of several human cancers. Wnt inhibitory factor-1 (Wif-1) was identified as one of the secreted antagonists that can bind Wnt protein. We hypothesize that Wif-1 plays an important role in bladder cancer pathogenesis. EXPERIMENTAL DESIGN: To test this hypothesis, epigenetic and genetic pathways involved in the Wif-1 gene modulation and expression of Wnt/beta-catenin-related genes were analyzed in 4 bladder tumor cell lines and 54 bladder tumor and matched normal bladder mucosa. RESULTS: Wif-1 mRNA expression was significantly enhanced after 5-aza-2'-deoxycytidine treatment in bladder tumor cell lines. Wif-1 promoter methylation level was significantly higher and Wif-1 mRNA expression was significantly lower in bladder tumor samples than in bladder mucosa samples. In the total bladder tumor and bladder mucosa samples, an inverse correlation was found between promoter methylation and Wif-1 mRNA transcript levels. However, loss-of-heterozygosity at chromosome 12q14.3 close to the Wif-1 gene loci was a rare event (3.7%). Nuclear accumulation of beta-catenin was significantly more frequent in bladder tumor than in bladder mucosa and inversely correlated with Wif-1 expression. In addition, known targets of the canonical Wnt/beta-catenin signaling pathway, such as c-myc and cyclin D1, were up-regulated in bladder tumor compared with bladder mucosa, and this up-regulation was associated with reduced Wif-1 expression at both mRNA and protein levels. Furthermore, transfection of Wif-1 small interfering RNA into bladder tumor cells expressing Wif-1 mRNA transcripts had increased levels of c-myc and cyclin D1 and accelerated cell growth. CONCLUSION: This is the first report showing that CpG hypermethylation of the Wif-1 promoter is a frequent event in bladder tumor and may contribute to pathogenesis of bladder cancer through aberrant canonical Wnt/beta-catenin signaling pathway. The present study elucidates novel pathways that are involved in the pathogenesis of bladder cancer.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Smoking influences aberrant CpG hypermethylation of multiple genes in human prostate carcinoma.

BACKGROUND: Aberrant CpG methylation profiles of gene promoters and their correlation with advanced pathologic features have been well investigated in prostate carcinoma (PC). Several case-control and prospective studies have revealed a positive association between current smoking and PC. The authors hypothesized that smoking influences both progression and prognosis of PC through CpG hypermethylation of related genes. METHODS: A total of 164 PC patients (52 current, 30 former, and 82 never smokers) and 69 benign prostatic hyperplasia (BPH) patients were examined by methylation-specific PCR (MSP) for 3 genes: adenomatous polyposis coli (APC), glutathione S-transferase pi (GSTP1), and multidrug resistance one (MDR1). The methylation status of representative samples was confirmed by bisulfite DNA sequencing analysis. The newly defined methylation score (M-score) of each sample is the sum of the corresponding log hazard ratio (HR) coefficients derived from multivariate logistic regression analysis for pathology (BPH vs. PC), and was related to clinical and pathologic outcome including smoking status. RESULTS: The M-score was significantly higher in the current smokers than in never smokers (P = 0.008). Spearman rank correlation test demonstrated a significant correlation between pack-years smoked and M-score in PCs (P = 0.039). Significant correlation of the M-score methylation was observed with high pT category (P < 0.001), high Gleason sum (P < 0.001), high preoperative prostate-specific antigen (PSA) (P = 0.041), and advanced pathologic features. In addition, Gleason sum was significantly associated with PSA failure-free probability as a poor outcome (P = 0.020). CONCLUSIONS: This is the first study to demonstrate significant correlation of the methylation status of multigenes with smoking status in PC. Smoking status may influence both progression and prognosis of PC through CpG hypermethylation of related genes.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2006

The E-cadherin -160 C/A polymorphism and prostate cancer risk in white and black American men.

PURPOSE: We have previously reported that a C/A single nucleotide polymorphism at position -160 of the human E-cadherin gene promoter affects E-cadherin transcription. Although this single nucleotide polymorphism is associated with a number of human cancers, including prostate cancer, it is not known whether it has a role in race related prostate cancer. We hypothesized that allelic variation at this site may be associated with racial differences in the incidence and severity of prostate cancer. MATERIALS AND METHODS: We analyzed the genotypes of this single nucleotide polymorphism in a total of 135 prostate cancer samples from 86 white and 49 black American men, and in 237 samples from normal healthy controls, including 120 white and 117 black men, using the polymerase chain reaction-restriction fragment length polymorphism technique. RESULTS: Of normal controls black men had a higher frequency of the A allele and CA genotype than white men (26.5 and 39.3 vs 22.5 and 28.3, respectively). In white men A allele frequency was significantly higher in those with prostate cancer than in controls (p <0.05). White men carrying the A allele and AA genotype were at 1.99-fold (95% CI 1.29 to 3.08) and 3.04-fold (95% CI 1.26 to 7.32) higher risk for prostate cancer than carriers of the C allele and CC genotype. However, in black men the A allele was more frequent in controls than in patients with cancer and it was associated with a 2.4-fold decrease in prostate cancer risk (95% CI 0.22 to 0.81) compared to the C allele. CONCLUSIONS: The A allele of the E-cadherin -160 single nucleotide polymorphism represents a prostate cancer risk factor in white but not in black men.

Black or African American↗

PubMed2006

Catechol-O-methyltransferase gene polymorphisms in benign prostatic hyperplasia and sporadic prostate cancer.

Various carcinogenic metabolites, including catechol estrogens, play a role in malignant transformation. An enzyme that is capable of neutralizing the genotoxic effects of these compounds is catechol-O-methyltransferase (COMT). A variant form of this enzyme has been shown to reduce its activity by up to 4-fold; thus, we hypothesize that single nucleotide polymorphisms of the COMT gene can be a risk factor for benign prostatic hyperplasia (BPH) and prostate cancer. To test this hypothesis, the genetic distribution of three different COMT polymorphisms at codon 62 (C-->T), codon 72 (G-->T), and codon 158 (G-->A) were analyzed in 131 normal healthy subjects, 134 BPH, and 178 sporadic prostate cancer samples from a Japanese population. Results of these experiments show that the variant genotype at codon 62 (P = 0.060) and codon 158 (P = 0.047) are risk factors for prostate cancer but not BPH when compared with normal controls. Odds ratio (OR) and 95% confidence interval (95% CI) for cancer were 3.24 and 1.38 to 7.61, respectively, for codon 62 T/T genotype when compared with wild type. At codon 158, the A/A variant for cancer had an OR of 3.00 with a 95% CI of 1.38 to 6.54 compared with wild type. Codons 62 and 158 were in linkage disequilibrium (LD), and when compared with the C-G haplotype, other types (C-A, T-G, T-A) were observed to be associated with prostate cancer (P = 0.040) but not BPH. Codon 72 on the other hand, was not in LD with either codon 62 or 158. The homozygous variant on codon 72 was rare in this Japanese population, and the heterozygous G/T at this codon was not associated with either prostate cancer or BPH. When evaluating the risk of COMT polymorphisms with stage or grade of cancer, no associations were observed for any of the genotypes with the exception of a tendency (P = 0.096) for the variant A allele on codon 158 to be correlated with higher stages (> or = T3) of cancer. This is the first report that shows the polymorphisms of COMT to be associated with sporadic prostatic carcinogenesis. These results are important in understanding the role of COMT polymorphisms in the pathogenesis of prostate cancer.

Alleles↗

PubMed2005

WT1 and WT1-AS genes are inactivated by promoter methylation in ovarian clear cell adenocarcinoma.

BACKGROUND: Ovarian clear cell adenocarcinoma is associated with one of the poorest prognoses among human epithelial ovarian cancers. The authors hypothesized that Wilms tumor suppressor 1 gene (WT1) sense and antisense (WT1-AS) expression and their promoter methylation status could characterize ovarian clear cell adenocarcinoma from ovarian serous adenocarcinoma. METHODS: To test this hypothesis, ovarian cancer cell lines and 42 cancer tissues (17 clear cell and 25 serous adenocarcinoma) were analyzed for expression and methylation of WT1 and WT1-AS genes. RESULTS: These experiments demonstrated that all serous adenocarcinoma tissues expressed both WT1 and WT1-AS genes, although expression of these genes was lacking in clear cell adenocarcinoma. The WT1 and WT1-AS promoter were significantly methylated in clear cell adenocarcinoma (88.2% and 88.2%, respectively) compared with serous adenocarcinoma (24.0% and 20.0%, respectively). Significant correlation between methylation and mRNA expression status was observed for each gene. Also in agreement with these data, WT1 and WT1-AS negative ovarian cancer cell lines reexpressed these genes after treatment with the demethylating agent, 5-aza-2'-deoxycytidine. CONCLUSIONS: The current study shows that CpG hypermethylation is an important mechanism of WT1 and WT1-AS gene inactivation in ovarian clear cell adenocarcinoma. This is the first report that has demonstrated differential expression and methylation of WT1-AS in ovarian clear cell and serous adenocarcinomas. This study presents new molecular characterizations between these two types of adenocarcinoma and may provide insight as to why clear cell adenocarcinoma has a poorer prognosis than serous adenocarcinoma of the ovary.

Adenocarcinoma, Clear Cell↗

PubMed2005

Promoter CpG hypomethylation and transcription factor EGR1 hyperactivate heparanase expression in bladder cancer.

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-Aza-dC 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 (P<0.01). 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 (P<0.05) and inversely correlated with heparanase expression (P=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.

Base Sequence↗

PubMed2005

Multigene methylation analysis for detection and staging of prostate cancer.

PURPOSE: Aberrant gene promoter methylation profiles have been well-studied in human prostate cancer. Therefore, we rationalize that multigene methylation analysis could be useful as a diagnostic biomarker. We hypothesize that a new method of multigene methylation analysis could be a good diagnostic and staging biomarker for prostate cancer. EXPERIMENTAL DESIGN: To test our hypothesis, prostate cancer samples (170) and benign prostatic hyperplasia samples (69) were examined by methylation-specific PCR for three genes: adenomatous polyposis coli (APC), glutathione S-transferase pi (GSTP1), and multidrug resistance 1 (MDR1). The methylation status of representative samples was confirmed by bisulfite DNA sequencing analysis. We further investigated whether methylation score (M score) can be used as a diagnostic and staging biomarker for prostate cancer. The M score of each sample was calculated as the sum of the corresponding log hazard ratio coefficients derived from multivariate logistic regression analysis of methylation status of various genes for benign prostatic hyperplasia and prostate cancer. The optimal sensitivity and specificity of the M score for diagnosis and for staging of prostate cancer was determined by receiver-operator characteristic (ROC) curve analysis. A pairwise comparison was employed to test for significance using the area under the ROC curve analysis. For each clinicopathologic finding, the association with prostate-specific antigen (PSA) failure-free probability was determined using Kaplan-Meier curves and a log-rank test was used to determine significance. The relationship between M score and clinicopathologic findings was analyzed by either the Mann-Whitney U test, Kruskal-Wallis test, or the Spearman rank correlation test. RESULTS: The frequency of positive methylation-specific PCR bands for APC, GSTP1, and MDR1 genes in prostate cancer samples was 64.1%, 54.0%, and 55.3%, respectively. In benign prostatic hyperplasia samples, it was 8.7%, 5.8%, and 11.6%, respectively. There was a significant correlation of M score with high pT category (P < 0.001), high Gleason sum (P < 0.001), high preoperative PSA (P = 0.027), and advanced pathologic features. For all patients, the M score had a sensitivity of 75.9% and a specificity of 84.1% as a diagnostic biomarker using a cutoff value of 1.0. In patients with low or borderline PSA levels (<10.0 ng/mL), the M score was significantly higher in prostate cancers than in benign prostatic hyperplasias (2.635 +/- 0.200 and 0.357 +/- 0.121, respectively). ROC curve analysis revealed that the M score had a sensitivity of 65.4% and a specificity of 94.2% when 1.0 was used as a cutoff value. For all patients, M score can distinguish organ-confined (< or =pT(2)) from locally advanced cancer (> or =pT(3)) with a sensitivity of 72.1% and a specificity of 67.8%. Moreover, considering patients with PSA levels of <10 ng/mL, the M score has a sensitivity of 67.1% and a specificity of 85.7%. The ROC curve analysis showed a significant difference between M score and PSA (P = 0.010). CONCLUSIONS: This is the first report demonstrating that M score is a new method for multigene methylation analysis that can serve as a good diagnostic and staging biomarker for prostate cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2005

Ethnic group-related differences in CpG hypermethylation of the GSTP1 gene promoter among African-American, Caucasian and Asian patients with prostate cancer.

The incidence and mortality of prostate cancer (PC) is approximately 2-fold higher among African-Americans as compared to Caucasians and very low in Asian. We hypothesize that inactivation of GSTP1 genes through CpG methylation plays a role in the pathogenesis of PC, and its ability to serve as a diagnostic marker that differs among ethnic groups. GSTP1 promoter hypermethylation and its correlation with clinico-pathological findings were evaluated in 291 PC (Asian = 170; African-American = 44; Caucasian = 77) and 172 benign prostate hypertrophy samples (BPH) (Asian = 96; African-American = 38; Caucasian = 38) using methylation-specific PCR. In PC cells, 5-aza-dC treatment increased expression of GSTP1 mRNA transcripts. The methylation of all CpG sites was found in 191 of 291 PC (65.6%), but only in 34 of 139 BPH (24.5%). The GSTP1 hypermethylation was significantly higher in PC as compared to BPH in each ethnic group (p < 0.0001). Logistic regression analysis (PC vs. BPH) showed that African-Americans had a higher hazard ratio (HR) (13.361) compared to Caucasians (3.829) and Asian (8.603). Chi-square analysis showed correlation of GSTP1 hypermethylation with pathological findings (pT categories and higher Gleason sum) in Asian PC (p < 0.0001) but not in African-Americans and Caucasian PC. Our results suggest that GSTP1 hypermethylation is a sensitive biomarker in African-Americans as compared to that in Caucasians or Asian, and that it strongly influences tumor progression in Asian PC. Ours is the first study investigating GSTP1 methylation differences in PC among African-American, Caucasian and Asian.

Adult↗