Influence of a single-nucleotide polymorphism of the DNA mismatch repair-related gene exonuclease-1 (rs9350) with prostate cancer risk among Chinese people.

In this study, we aimed to identify the influence of exonuclease 1 (EXO1) single-nucleotide polymorphism rs9350, which is involved in DNA mismatch repair, on prostate cancer risk in Chinese people. In our hospital-based case-control study, 214 prostate cancer patients and 253 cancer-free control subjects were enrolled from three hospitals in China. Genotyping for rs9350 was performed by the SNaPshot(®) method using peripheral blood samples. Consequently, a significantly higher prostate cancer risk was observed in patients with the CC genotype [odds ratio (OR) = 1.678, 95 % confidence interval (CI) = 1.130-2.494, P = 0.010] than in those with the CT genotype. Further, the CT/TT genotypes were significantly associated with increased prostate cancer risk (adjusted OR = 1.714, 95 % CI = 1.176-2.500, P = 0.005), and the C allele had a statistically significant compared with T allele (P = 0.009) of EXO1 (rs9350). Through stratified analysis, significant associations were revealed for the CT/TT genotype in the subgroup with diagnosis age >72 (adjusted OR = 1.776, 95 % CI = 1.051-3.002, P = 0.032) and in patients with localized disease subgroup (adjusted OR = 1.798, 95 % CI = 1.070-3.022, P = 0.027). In addition, we observed that patients with prostate-specific antigen (PSA) levels of ≤10 ng/mL were more likely to have the CT/TT genotypes than those with PSA levels of >10 ng/mL (P = 0.006). For the first time, we present evidence that the inherited EXO1 polymorphism rs9350 may have a substantial influence on prostate cancer risk in Chinese people. We believe that the rs9350 could be a useful biomarker for assessing predisposition for and early diagnosis of prostate cancer.

Dose-response analysis of testosterone replacement therapy in patients with female to male gender identity disorder.

Gender identity disorder (GID) is a conflict between a person's actual physical gender and the one they identify him or herself with. Testosterone is the key agent in the medical treatment of female to male GID patients. We conducted a dose-response analysis of testosterone replacement therapy (TRT) in 138 patients to determine the onset of the therapeutic effects. The TRT consisted of intramuscular injection of testosterone enanthate and patients were divided into three groups; 250 mg every two weeks, 250 mg every three weeks and 125 mg every two weeks. The onset of deepening of voice, increase in facial hair and cessation of menses was evaluated in each group. At one month after the start of TRT, the onset of these physical changes was more prevalent in the group receiving the higher dose of testosterone, and there were dose-dependent effects observed between the three treatment groups. On the other hand, at six months after the start of TRT, most of the patients had achieved treatment responses and there were no dose-dependent effects with regard to the percentage of patients with therapeutic effects. No significant side effects were observed in any of the treatment groups. We demonstrated that the early onset of the treatment effects of TRT is dose-dependent, but within six months of starting TRT, all three doses were highly effective. Current study provides useful information to determine the initial dose of TRT and to suggest possible changes that should be made in the continuous dosage for long term TRT.

Preclinical safety and efficacy of in situ REIC/Dkk-3 gene therapy for prostate cancer.

The preclinical safety and therapeutic efficacy of adenoviral vectors that express the REIC/Dkk-3 tumor suppressor gene (Ad-REIC) was examined for use in prostate cancer gene therapy. The Ad-human (h) and mouse (m) REIC were previously demonstrated to induce strong anti-cancer effects in vitro and in vivo, and we herein report the results of two in vivo studies. First, intra-tumor Ad-hREIC administration was examined for toxicity and therapeutic effects in a subcutaneous tumor model using the PC3 prostate cancer cell line. Second, intra-prostatic Ad-mREIC administration was tested for toxicity in normal mice. The whole-body and spleen weights, hematological and serum chemistry parameters, and histological evaluation of tissues from throughout the body were analyzed. Both experiments indicated that there was no significant difference in the examined parameters between the Ad-REIC-treated group and the control (PBS- or Ad-LacZ-treated) group. In the in vitro analysis using PC3 cells, a significant apoptotic effect was observed after Ad-hREIC treatment. Confirming this observation, the robust anti-tumor efficacy of Ad-hREIC was demonstrated in the in vivo subcutaneous prostate cancer model. Based on the results of these preclinical experiments, we consider the adenovirus-mediated REIC/Dkk-3 in situ gene therapy to be safe and useful for the clinical treatment of prostate cancer.

Tumor suppressor REIC/Dkk-3 interacts with the dynein light chain, Tctex-1.

REIC/Dkk-3 is a member of the Dickkopf family proteins known as Wnt-antagonists, and REIC/Dkk-3 expression is downregulated in a broad range of cancer types. REIC/Dkk-3 acts as a tumor suppressor in multiple cancer cell lines by inducing apoptosis through endoplasmic reticulum (ER) stress signaling. However, the intracellular interaction partners of REIC/Dkk-3 have not been fully elucidated. By employing yeast two-hybrid screening, we identified the human dynein light chain, Tctex-1, as a novel interaction partner of REIC/Dkk-3. We further disclosed that the interaction involves the 136-157 amino acid region of REIC/Dkk-3 by using the mammalian two-hybrid system. Interestingly, this binding region of REIC/Dkk-3 with Tctex-1 contains an amino acid sequence motif [-E-X-G-R-R-X-H-] which was previously reported as the Tctex-1 binding domain of dynein intermediate chain (DIC). Immunocytochemistry demonstrated that both REIC/Dkk-3 and Tctex-1 were localized around the ER of human fibroblasts, and the similar distribution pattern of the proteins suggests that their interaction occurs around the ER. This is the first study showing the interaction of a Dickkopf family protein with a dynein motor complex protein. The link between REIC/Dkk-3 and Tctex-1 may be of significance for understanding the molecular functions of the proteins in ER stress signaling and intracellular dynein motor dynamics, respectively.

Single nucleotide polymorphism WRN Leu1074Phe is associated with prostate cancer susceptibility in Chinese subjects.

Deficiencies in the human DNA repair gene WRN are the cause of Werner syndrome, a rare autosomal recessive disorder characterized by premature aging and a predisposition to cancer. This study evaluated the association of WRN Leu1074Phe (rs1801195), a common missense single nucleotide polymorphism in WRN, with prostate cancer susceptibility in Chinese subjects. One hundred and forty-seven prostate cancer patients and 111 male cancer-free control subjects from 3 university hospitals in China were included. Blood samples were obtained from each subject, and the single nucleotide polymorphism WRN Leu1074Phe was genotyped by using a Snapshot assay. The results showed that WRN Leu1074Phe was associated with the risk of prostate cancer in Chinese men and that the TG/GG genotype displayed a decreased prevalence of prostate cancer compared with the TT genotype (OR＝0.58, 95%CI:0.35-0.97, p＝0.039). Through stratified analysis, more significant associations were revealed for the TG/GG genotype in the subgroup with diagnosis age ≤ 72 yr (OR＝0.27, 95%CI:0.12-0.61, p＝0.002) and in patients with localized diseases (OR＝0.36, 95%CI:0.19-0.70, p＝0.003). However, no statistically significant difference was found in the subgroup with age ＞72 yr or in patients with advanced diseases. We concluded that the genetic variant Leu1074Phe in the DNA repair gene WRN might play a role in the risk of prostate cancer in Chinese subjects.

Mechanistic analysis of resistance to REIC/Dkk-3-induced apoptosis in human bladder cancer cells.

We have recently shown that a new therapeutic modality using the REIC/Dkk-3 gene (Ad-REIC) is effective against various human cancers, including those of prostate, testis and breast origins. The aim of the present study was to examine the sensitivity of bladder cancers to Ad-REIC and to clarify the molecular mechanisms that determine sensitivity/resistance. We found that 2 human bladder cancer cell lines, T24 and J82, are resistant to Ad-REIC. In T24 and J82 cells, the ER stress response and activation of JNK were observed in a manner similar to that in the sensitive PC3 cells. Translocation of Bax to mitochondria occurred in PC3 cells but not in T24 and J82 cells. Bcl-2 was remarkably overexpressed in T24 and J82 compared with the expression levels in sensitive cell lines. Treatment of T24 and J82 cells with a Bcl-2 inhibitor sensitized the cells to Ad-REIC-induced apoptosis. The results indicate that some human bladder cancers are resistant to apoptosis induced by overexpression of REIC/Dkk-3, which is at least in part due to up-regulation of Bcl-2. These results provide a basis for possible use of Bcl-2 as a marker of sensitive cancers and to try to sensitize resistant cancers to Ad-REIC by down-regulation of Bcl-2.

Heat shock proteins play a crucial role in tumor-specific apoptosis by REIC/Dkk-3.

We recently showed that overexpression of REIC/Dickkopf-3 (Dkk-3), a tumor suppressor gene, induced apoptosis in a tumor cell-specific manner. The aim of the present study was to determine the mechanisms underlying the selective induction of apoptosis. At first, we found a mouse renal carcinoma cell line, RENCA, to be extremely sensitive to an adenovirus carrying REIC/Dkk-3 (Ad-REIC), and we showed that activation of c-Jun N-terminal kinase (JNK) was a critical step in cell death, i.e. a process similar to that in human prostate and testicular cancer observed in our previous studies. Among the proteins interfering with the activation of JNK, heat shock protein (Hsp)70/72 was reduced in expression in RENCA cells compared with that in NIH3T3 cells. An Hsp70/72 inducer protected RENCA cells from Ad-REIC-induced apoptosis, while an Hsp70/72 inhibitor sensitized NIH3T3 cells for apoptosis induction. These results indicate that functionally active Hsp70/72 is a key factor in tumor cell-specific induction of apoptotic cell death and that analyses of the expression levels of Hsp70/72 may be essential in determining the significance of Ad-REIC-based gene therapy against human cancer.

Routine transurethral biopsy of the bladder is not necessary to evaluate the response to bacillus calmette-guerin therapy.

We evaluated the need for transurethral biopsy at first follow-up after intravesical bacillus Calmette-Guerin (BCG) therapy for superficial bladder cancer. The records of 84 patients with superficial bladder cancer who received a 6- or 8-week course of BCG were reviewed. Pathological results before BCG, cystoscopic findings, urinary cytology, and biopsy results for evaluation of BCG therapy were reviewed. All 19 patients with positive urinary cytology had evidence of positive bladder biopsy results. Fifty-three of 54 patients (98.1%) with no visible recurrent tumor and negative urinary cytology demonstrated negative pathological results on bladder biopsy. When not found in conjunction with positive urinary cytology, erythematous mucosa on cystoscopy was not an indicator of tumor recurrence or residual cancer. In conclusion, routine transurethral biopsy of the bladder for evaluating the response to BCG intravesical therapy is not necessary in patients who have no visible tumor on cystoscopy and negative urinary cytology.

Combination chemotherapy with estramustine phosphate, ifosfamide and cisplatin for hormone-refractory prostate cancer.

We evaluated the efficiency and toxicity of estramustine phosphate (ECT), ifosfamide (IFM) and cisplatin (CDDP) combination chemotherapy in twenty-one patients with hormone-refractory prostate cancer (HRPC), for which there is currently no effective treatment. Patients received a daily dose of 560 mg ECT in combination with 1.2 g/m2 IFM on days 1 to 5 and 70 mg/m2 CDDP on day 1. This combination therapy was given every 3 to 4 weeks. An objective response of more than 50% reduction in prostate-specific antigen was observed in 9 of 18 patients (50%), and a more than 50% reduction in bi-dimensionally measurable soft-tissue lesions was observed in 2 of 7 patients (29%). The median duration of response among the cases showing partial response was 40 weeks, while the median duration of response of overall partial-response plus stable cases was 30 weeks. The median survival duration of all cases was 47 weeks. Toxicity was modest and acceptable. In conclusion, the ECT, IFM and CDDP combination chemotherapy regimen is a viable treatment option for HRPC. However, in comparison with our previous chemotherapy regimen of IFM and CDDP, no additional long-lasting effects resulting from the inclusion of ECT could be affirmed.

Long-term clinical outcomes of 420 consecutive prostate cancer patients in a single institute.

This study was undertaken to reveal the trends of prostate cancer and the outcome of treatment modalities for each disease stage in patients in a single institute over a 10-year period. From January 1994 through December 2003, 420 consecutive patients with previously untreated and histologically confirmed prostate cancer were analyzed for annual distributions of disease stages and treatment modalities and for long-term clinical progression-free survival, prostate cancer-specific survival, and prostate-specific antigen (PSA) failure-free survival rates for each stage and treatment modality. Annual trends showed that the number of patients, especially those with clinically localized cancer, increased dramatically. The 5-year disease-specific survival rates for patients with clinically localized disease were 100 percent for all treatment modalities, including hormonal therapy alone. Patients with PSA levels less than 10 ng/ml showed an 81 percent 5-year PSA failure-free survival rate with radical prostatectomy. Stage C patients treated by surgery or radiation-based therapy with concomitant hormonal therapy obtained 93 percent and 100 percent cause-specific survival rates, respectively, and those treated by hormonal therapy alone showed a 79 percent rate. The number of patients with localized prostate cancer was increasing in this decade. While long-term hormonal therapy alone was highly efficient in controlling localized prostate cancer, radical therapies in conjunction with neo-adjuvant hormonal therapy produced better survival rates in cases of locally advanced disease.

A combination of YM-155, a small molecule survivin inhibitor, and IL-2 potently suppresses renal cell carcinoma in murine model.

YM155, a small molecule inhibitor of the antiapoptotic protein survivin, has been developed as a potential anti-cancer drug. We investigated a combination therapy of YM155 and interleukin-2 (IL-2) in a mouse model of renal cell carcinoma (RCC). YM155 caused cell cycle arrest and apoptosis in renal cancer (RENCA) cells. Next, luciferase-expressing RENCA cells were implanted in the left kidney and the lung of BALB/c mice to develop RCC metastatic model. In this orthotopic renal and metastatic lung tumors models, YM155 and IL-2 additively decreased tumor weight, lung metastasis, and luciferin-stained tumor images. Also, the combination significantly suppressed regulatory T cells and myeloid-derived suppressor cells compared with single agent treatment. We suggest that a combination of YM155 and IL-2 can be tested as a potential therapeutic modality in patients with RCC.

Anterior urethral recurrence of superficial bladder cancer: its clinical significance.

The aim of this study was to reveal the clinical features of anterior urethral recurrence in patients with superficial bladder cancer, and to determine the appropriate treatment. Three hundred and three patients with superficial bladder cancer, who were newly diagnosed and initially treated conservatively in our hospital between 1965 and 1990, were followed for at least 5 years and their clinical outcomes were analyzed. Clinical factors, including anterior urethral recurrence, were evaluated statistically regarding tumor progression. Eight patients (2.6%) had anterior urethral recurrence following superficial bladder cancer. Twenty-four patients (7.9%) had tumor progression and 149 (49.2%) had tumor recurrence. In a multivariate analysis using a logistic model, anterior urethral recurrence was the most important factor, followed by histological grade. Four of 5 patients who were treated for anterior urethral recurrent tumors by transurethral resection showed progression and died of the cancer within one year. Two of the remaining three patients who underwent radical cysto-urethrectomy at the time of anterior urethral recurrence survived. Anterior urethral recurrence following superficial bladder cancer is a predictor for rapid subsequent malignant progression. Once there is anterior urethral recurrence, radical intensive therapy, including radical cysto-urethrectomy, should be carried out immediately.

Significant association between the Axin2 rs2240308 single nucleotide polymorphism and the incidence of prostate cancer.

The Wnt signaling pathway plays a crucial role in human cancer development, and axis inhibition protein 2 (Axin2) is a master scaffold protein involved in Wnt signaling. Axin2 negatively regulates Wnt signaling and acts as a tumor suppressor protein. The present study evaluated the association between the Axin2 single nucleotide polymorphism (SNP) rs2240308 [guanine (G)/adenine (A)] and the incidence of prostate cancer. In total, 103 patients with prostate cancer and 100 cancer-free control males were included in this case-control study, and were genotyped using the genomic DNA extracted from peripheral blood samples. The results revealed a higher incidence of prostate cancer in the subjects with the homozygous GG genotype and a reduced cancer incidence in the patients with the GA genotype of the rs2240308 SNP (G/A) in the Axin2 gene. The adjusted odds ratio for carriers with the GA genotype was 0.377 (95% CI, 0.206-0.688; P=0.001) and that for the AA genotype was 0.830 (95% CI, 0.309-2.232; P=0.712) compared with the GG genotype. Therefore, the GA genotype was found to exhibit a protective effect that decreased the risk of prostate cancer. To the best of our knowledge, this is the first study to demonstrate the significant association between this SNP (rs2240308, G/A) and the risk of prostate cancer. This association indicates the possibility that the variations in the Axin2 gene in this position may play a significant role in promoting the development of cancer in the prostate. We believe that the Axin2 SNP (rs2240308) could be a useful biomarker for the predisposition and early diagnosis of the disease.

A novel gene expression system strongly enhances the anticancer effects of a REIC/Dkk-3-encoding adenoviral vector.

Gene expression systems with various promoters, including the cytomegalovirus (CMV) promoter, have been developed to increase the gene expression in a variety of normal and cancer cells. In particular, in the clinical trials of cancer gene therapy, a more efficient and robust gene expression system is required to achieve sufficient therapeutic outcomes. By inserting the triple translational enhancer sequences of human telomerase reverse transcriptase (hTERT), Simian virus 40 (SV40) and CMV downstream of the sequence of the BGH polyA, we were able to develop a novel gene expression system that significantly enhances the expression of the genes of interest. We termed this novel gene expression cassette the super gene expression (SGE) system, and herein verify the utility of the SGE cassette for a replication-deficient adenoviral vector. We newly developed an adenoviral vector expressing the tumor suppressor, reduced expression in immortalized cells (REIC)/Dickkopf-3 (Dkk-3), based on the CMV promoter-driven SGE system (Ad-SGE-REIC) and compared the therapeutic utility of Ad-SGE-REIC with that of the conventional adenoviral vectors (Ad-CMV-REIC or Ad-CAG-REIC). The results demonstrated that the CMV promoter-SGE system allows for more potent gene expression, and that the Ad-SGE-REIC is superior to conventional adenoviral systems in terms of the REIC protein expression and therapeutic effects. Since the SGE cassette can be applied for the expression of various therapeutic genes using various vector systems, we believe that this novel system will become an innovative tool in the field of gene expression and gene therapy.

Dramatic increase in expression of a transgene by insertion of promoters downstream of the cargo gene.

For expression of genes in mammalian cells, various vectors have been developed using promoters including CMV, EF-1α, and CAG promoters and have been widely used. However, such expression vectors sometimes fail to attain sufficient expression levels depending on the nature of cargo genes and/or on host cell types. In the present study, we aimed to develop a potent promoter system that enables high expression levels of cargo genes ubiquitously in many different cell types. We found that insertion of an additional promoter downstream of a cargo gene greatly enhanced the expression levels. Among the constructs we tested, C-TSC cassette (C: CMV-RU5' located upstream; TSC: another promoter unit composed of triple tandem promoters, hTERT, SV40, and CMV, located downstream of the cDNA plus a polyadenylation signal) had the most potent capability, showing far higher efficiency than that of potent conventional vector systems. The results indicate that the new expression system is useful for production of recombinant proteins in mammalian cells and for application as a gene therapeutic measure.

Cancer stem cell-like characteristics of a CD133+ subpopulation in the J82 human bladder cancer cell line.

Cancer stem cells (CSCs) are thought to be crucial for understanding the biological roots of cancer, and are of increasing importance as a target for new anticancer agents. According to an expression analysis of the cell surface antigens of various types of cancer, CD133 is considered to be a potential marker of cancer stemness. In this study, a human urinary bladder cancer cell line (J82) was used to analyze the cancer stem cell-like characteristics of CD133+ bladder cancer cells in vitro and in vivo. The CD133 expression in the J82 cells was examined and the cells were immunomagnetically categorized into positive and negative subsets. The CD133- and CD133+ subsets were phenotypically divergent with regard to the cell growth pattern, while CD133+ cells tended to colonize during their growth. In CD133+ cells, the pluripotent stem cell factors Oct-4 and Sox-2 were upregulated, and a statistically significant proliferation increase was observed when compared to CD133- cells. The CD133+ subpopulation was more tolerant to the chemotherapeutic agent cisplatin, and Bacillus Calmette-Guérin (BCG), an agent instilled intravesically to treat bladder cancer. In addition, CD133+ J82 cells were more resistant to radiation treatment when compared to CD133- cells. The in vivo tumorigenesis of the CD133- and CD133+ subsets of J82 cancer cells was also examined by subcutaneously injecting them into nude mice. The tumor growth was more aggressive in the CD133+ subpopulation, showing a significant difference in the tumorigenic potential in these subsets. In conclusion, J82 human bladder cancer cells include CD133- and CD133+ subpopulations, while the CD133 molecule is a potential marker of the potential malignancy of human bladder cancer. In the present study, the CD133+ subpopulation was herein demonstrated to have certain characteristics consistent with those of cancer stem cells.

Clinical significance of CD24 as a predictor of bladder cancer recurrence.

Cluster of differentiation (CD)24 was originally described as a B lymphocyte marker and has recently received considerable attention in cancer research as its overexpression has been observed in several types of carcinoma. The CD24 molecule is a glycosyl-phosphatidylinositol-linked cell surface protein that appears to be associated with aggressive cancers involving invasion and metastasis. However, the expression of CD24 in human bladder cancer and its clinical significance remains largely unknown and no association has been reported between CD24 overexpression and human bladder tumor recurrence. In the present study, the CD24 expression in cancer tissues obtained during transurethral surgery and the subsequent intra-bladder tumor recurrence following surgery were assessed. Immunohistochemical staining was performed and the intensity of CD24 staining was semi-quantitatively evaluated. CD24 expression was observed more frequently in high-grade bladder tumors (G2-G3) than low-grade tumors (G1). Positive CD24 expression was significantly associated with intra-bladder tumor recurrence following surgery and increased staining intensity was also correlated with recurrence. The positive association between CD24 expression and tumor recurrence was observed in each tumor category (stages Ta and T1, low and high grade). The results demonstrated that CD24 expression is significantly associated with bladder tumor recurrence. To the best of our knowledge, this is the first study to reveal the significance of CD24 as a predictor of bladder cancer recurrence. These insights may lead to future therapeutic strategies targeting CD24 to prevent the dissemination of bladder cancer cells and tumor recurrence.

Preclinical biodistribution and safety study of reduced expression in immortalized cells/Dickkopf-3-encoding adenoviral vector for prostate cancer gene therapy.

The biodistribution and safety of adenoviral vectors encoding the human REIC/Dkk-3 tumor suppressor gene (Ad-REIC) were examined in this preclinical study for in situ prostate cancer gene therapy. First, the in vitro apoptotic effects of Ad-REIC in normal and cancer cells derived from the prostate and liver were examined. Significant apoptotic effects were observed at 100 MOI (multiplicity of infection) in prostate cancer cells (LNCaP, PC3) and hepatoma cells (HEP3B and HEPG2); however, no effects were seen in normal cells. To analyze the safety of intraprostatic Ad-REIC administration, the biodistribution and histology after Ad-REIC injection were evaluated in various organs of normal male C57BL6 mice. In a supporting study, vector dissemination following intravenous injection of Ad-REIC into tail veins was determined. To evaluate whether Ad-REIC was present in the collected tissue specimens, human REIC gene detection was performed using DNA-PCR. Intraprostatic treatment administered at lower doses showed vector biodistribution into the colon, urinary bladder and prostate. At higher doses, vector dissemination was observed in tissues more distant from the prostate, including the lung, thymus, heart, liver and adrenal gland. After intravenous injection of Ad-REIC, dissemination was observed in the liver and spleen. These results indicate that the biodistribution of Ad-REIC is determined by the dose and route of administration. Although acute inflammatory effects were observed in the prostate after intraprostatic administration at higher doses, no abnormal histological findings were noted in the other tissues, including those of intravenously treated mice. Regarding the safety of Ad-REIC administration, no deaths and no signs of toxicity or unusual behavior were observed in the mice in any treatment group. Based on these preclinical experiments, adenovirus-mediated in situ REIC/Dkk-3 gene therapy is considered to be safe for use as a treatment for human prostate cancer.