Polymorphisms of MLH1 in benign prostatic hyperplasia and sporadic prostate cancer.

Mismatch repair is one of several DNA repair pathways of which defects may lead to cancer. We hypothesize that polymorphisms of the MLH1 gene can be a risk factor for benign prostatic hyperplasia (BPH) and prostate cancer. The genetic distribution of MLH1 polymorphisms that lead to amino acid changes at codons 132, 219, 384, and 723 were analyzed in BPH and sporadic prostate cancer patients, and compared to healthy controls from an Asian population. These experiments demonstrate a protective role for the codon 384 variant allele against prostate cancer (P=0.031) but not BPH when compared to normal controls and furthermore, an inverse association was observed with stage (P=0.074) and grade (P=0.056) of cancer. This is the first report that demonstrates a protective effect for the race-related MLH1 polymorphism at codon 384 against prostate cancer and these results are important in understanding their role in this disease.

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.

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.

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.

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.

Cytochrome P450 1B1 is overexpressed and regulated by hypomethylation in prostate cancer.

PURPOSE: Cytochrome P450 1B1 (CYP1B1), a dioxin inducible member of the CYP supergene family, is overexpressed in various human malignancies including prostate cancer. We hypothesized that promoter/enhancer CpG methylation contributes to the regulation of CYP1B1 expression in human prostate tissue. EXPERIMENTAL DESIGN: Expression and induction of the CYP1B1 gene in clinical prostate tissues and prostate cancer cell lines were investigated. The methylation status of the CYP1B1 gene was analyzed in 175 prostate cancer and 96 benign prostatic hyperplasia samples using methylation-specific PCR (MSP) and bisulfite-modified DNA sequencing. MSP primers covered dioxin response elements (DRE) and Sp1 sites that are important for the expression of CYP1B1. RESULTS: Expressions of CYP1B1 mRNA and protein were increased in prostate cancer. The aryl hydrocarbon receptor (AhR)/AhR nuclear translocator (ARNT) heterodimer complex activates gene transcription by binding to the DREs of CYP1B1. In prostate cancer cells, CYP1B1 mRNA was induced by 2,3,7,8-tetrachlorodigenzo-p-dioxin (TCDD) and/or demethylation agent (5-aza-2-deoxycytidine). There was no change in the expressions of AhR and ARNT. Methylation of promoter/enhancer regions was significantly higher in benign prostatic hyperplasia compared with prostate cancer. MSP-positive patients had significantly lower risk for prostate cancer as compared with MSP-negative patients. There was no correlation between CYP1B1 methylation status and clinicopathologic features. CONCLUSIONS: CYP1B1 is overexpressed in prostate cancer and regulated by hypomethylation of its promoter/enhancer region. This is the first report about CYP1B1 regulation in human clinical prostate samples showing that hypomethylation of the CYP1B1 gene may play an important role in prostate cancer.

Modulation of androgen receptor transactivation by gelsolin: a newly identified androgen receptor coregulator.

The partial agonist effect of antiandrogens has been well documented, and such effect is amplified by derived mutant androgen receptors (ARs) in prostate cancer cells. Here we report the identification of gelsolin (GSN) as an AR-associated protein. Hydroxyflutamide (HF), as well as androgens, can promote the interaction between AR and GSN in a dose-dependent manner. GSN interacts with AR DNA-binding domain and ligand-binding domain via its COOH-terminal domain. Immunolocalization studies show that GSN interacts with AR during nuclear translocation. Functional analyses additionally demonstrate that GSN enhances AR activity in the presence of either androgen or HF. Two peptides representing partial regions of the AR DNA-binding domain and the ligand-binding domain can block the GSN-enhanced AR activity. The expression of GSN is enhanced in LNCaP cells, LNCaP xenografts, and human prostate tumors after androgen depletion. Increasing expression of GSN enhances the AR activity in the presence of HF. Together, these data suggest that the weak androgenic effect of HF may be amplified by increasing the amount of GSN after androgen ablation treatment. Therefore, blockage of the interaction between AR and GSN could become a potential therapeutic target for the treatment of prostate cancer.

Prostate cancer mediates osteoclastogenesis through two different pathways.

The present study was undertaken to test the effects of prostate cancer cell lines (LNCaP, DU145, PC3, and MDA PCa 2b) on osteoclastogenesis. Crude conditioned medium (CM) from all four prostate cancer cell lines enhanced expression of the mRNA for receptor activator of NF-kappaB ligand (RANKL) in a mouse osteoblast cell line, MC3T3-E1; however, CM had no effect on expression of osteoprotegerin (OPG) mRNA. Coculture of MC3T3-E1 with prostate cancer cells yielded similar results. The number of mature osteoclasts induced by soluble RANKL increased significantly when osteoclast precursor cells were cultured with CM from LNCaP and DU145 cells. CM from LNCaP and DU145 cells also induced maturation from precursor in the absence of soluble RANKL, and this effect was not blocked by OPG. Addition of CM from DU145 cells increased expression of MMP-9 mRNA by osteoclast precursors. Our findings indicate that prostate cancer mediates osteoclastogenesis through induction of RANKL expression by osteoblasts and through direct actions on osteoclast precursors mediated by some factors other than RANKL.

[Angiosarcoma of the spleen 11 years after chemotherapy for testicular seminoma: a case report].

A 32-year-old man who had previously undergone chemotherapy for testicular seminoma 11 years ago was admitted to our hospital with a pain in the right leg. Computed tomography (CT) and bone scintigraphy revealed splenomegaly and multiple bone disease. Laboratory examination showed thrombocytopenia. The pathologic diagnosis of the resected spleen and the biopsied rib was angiosarcoma. We found no reports of angiosarcoma following previous chemotherapy for testicular cancer. It is unclear whether the angiosarcoma is a secondary neoplasm induced by the chemotherapy or not. However, the patient had a chromosomal aberration of the peripheral lymphocytes. The chemotherapy might also have affected the chromosomal aberration presumably in endothelial progenitor cells causing the development of a secondary neoplasm. To our knowledge, this is the first case of angiosarcoma after chemotherapy for testicular seminoma.

[Intraarterial chemotherapy with bladder preservation in patients with invasive bladder carcinoma].

Intraarterial chemotherapy (IAC) was carried out on patients with invasive bladder carcinoma to treat the bladder carcinoma while preserving the bladder. Fifteen patients with bladder carcinoma at stage T2-T4 were treated with intraarterial cisplatin (CDDP: 70 mg/m2) and adriamycin (ADM: 30 mg/m2) every 3 to 4 weeks. The response was observed in all 15 patients. Ten (66.7%) achieved a complete response (CR), and 3 (20.0%) obtained a partial response (PR). With a mean follow-up of 22.6 months, the overall survival rate was 86.7% and 12 patients were alive with functioning bladder. One patient received radical cystectomy. Although further studies and long-term follow up are required to clarify its effectiveness, IAC for patients with invasive bladder carcinoma might be an effective therapy with a preserved bladder.

[Hormonal chemotherapy for hormone-refractory prostate cancer].

To our knowledge, no standard chemotherapy for patients with hormone-refractory prostate cancer (HRPC) has been established. Since most patients with HRPC are elderly and have bone metastasis, cytotoxic chemotherapy causes them to be at high risk for myelosuppression. Therefore, chemotherapeutic agents with low toxicity and good compliance should be elected. We conducted three regimens for HRPC on an outpatient basis. Eligibility criteria were defined as serial rising PSA values on 3 or more occasions at least 2 weeks apart or radiological new or extensive lesions under hormonal therapy. The first regimen is comprised of cyclophosphamide (CPM), 100 mg/day, UFT, 400 mg/day, and estramustine phosphate (EMP), 560 mg/day in two daily fractions. The second regimen is comprised of an oral administration of dexamethasone (DEX) (0.5-2 mg/day). The third regimen is comprised of DEX, 1 mg/day, cyclophosphamide, 100 mg/day and UFT, 400 mg/day in two daily fractions. Post-therapy prostate-specific antigen (PSA) level in serum, objective response on bone scan or measurable disease, and symptomatic response on bone pain were assessed. All regimens showed clinical efficacy with mild toxicity. Indications and limitations of these regimens are discussed. Further, the combination trials of taxane and EMP in patients with HRPC are reviewed.

Possible correlation between polymorphism in the tumor necrosis factor-beta gene and the clinicopathological features of bladder cancer in Japanese patients.

OBJECTIVES: In a variety of cancers, several polymorphisms of the tumor necrosis factor (TNF) genes have been reported to result in different clinical outcomes. We investigated whether a polymorphism of the TNF gene is associated with a susceptibility to bladder cancer and its disease status. METHODS: Polymorphisms in the TNF-alpha gene promoter (-308 bp) and the NcoI site in the first intron of the TNF-beta gene were analyzed in 141 Japanese patients with bladder cancer and 173 Japanese controls by polymerase chain reaction-restriction fragment length polymorphism. The correlations between the polymorphisms of the TNF genes and the clinicopathological features were analyzed. RESULTS: The number of cases and controls with TNF-alpha2 was too small to be assessable. In contrast, the TNF-beta1/2 genotype at the NcoI site in the first intron conferred a 1.71-fold increased risk of bladder cancer compared to the TNF-beta2/2 genotype. In the bladder cancer group, patients with the TNF-beta1 allele had a significantly higher risk for a high-grade tumor (grade 3) or carcinoma in situ (CIS) than those without the TNF-beta1 allele. Moreover, in the superficial bladder cancers, patients with the TNF-beta1 allele showed a significantly higher intravesical recurrence rate than those without the TNF-beta1 allele. CONCLUSION: This polymorphism in the TNF-beta gene appears to be associated with tumor occurrence and disease status, such as the tumor grade and the presence of CIS. Further study with an increased sample size is warranted.

Inactivation of the hMSH3 mismatch repair gene in bladder cancer.

Deficiency in the DNA mismatch repair (MMR) is frequently involved in various cancers. The hMSH3 gene is one of the human MMR genes whose role in bladder cancer is not known. We hypothesized that down-regulation of the hMSH3 gene might be involved in bladder cancer. In this study we analyzed this gene with regard to frame-shift mutation, single nucleotide polymorphism (SNP), a 9bp repeat in exon 1, loss of heterozygosity (LOH), immunohistochemistry, and methylation status in 102 bladder cancer samples. Immunohistochemistry revealed that hMSH3 expression in bladder cancer was significant decreased compared to normal epithelium (p<0.0001). An inverse correlation with pathological grade was found. The frame-shift mutation in the (A) 8 tract was lacking in bladder cancer. There was no significantly difference between bladder cancer samples and healthy controls' with regard to SNP and the 9bp repeat. In bladder cancer, presence of the codon 222 polymorphism, LOH, and the 9bp repeats in exon 1 had a correlation with either pathological stage or pathological grade. Presence of the codon 1036 polymorphism had significant correlation with pathological stage and a trend to correlation with pathological grade. After 5-aza-dC treatment, MSH3 expression was significantly enhanced in TCC and UMUC bladder cancer cells when compared to untreated cells. This is the first report suggesting that genetic and epigenetic alterations in the human MSH3 gene might play a significant role in the progression of bladder tumors.