Wataru Obara

Molecular Features of Hormone-Refractory Prostate Cancer Cells by Genome-Wide Gene Expression Profiles

One of the most critical issues in prostate cancer clinic is emerging hormone-refractory prostate cancers (HRPCs) and their management. Prostate cancer is usually androgen dependent and responds well to androgen ablation therapy. However, at a certain stage, they eventually acquire androgen-independent and more aggressive phenotype and show poor response to any anticancer therapies. To characterize the molecular features of clinical HRPCs, we analyzed gene expression profiles of 25 clinical HRPCs and 10 hormone-sensitive prostate cancers (HSPCs) by genome-wide cDNA microarrays combining with laser microbeam microdissection. An unsupervised hierarchical clustering analysis clearly distinguished expression patterns of HRPC cells from those of HSPC cells. In addition, primary and metastatic HRPCs from three patients were closely clustered regardless of metastatic organs. A supervised analysis and permutation test identified 36 up-regulated genes and 70 down-regulated genes in HRPCs compared with HSPCs (average fold difference > 1.5; P < 0.0001). We observed overexpression of AR, ANLN, and SNRPE and down-regulation of NR4A1, CYP27A1, and HLA-A antigen in HRPC progression. AR overexpression is likely to play a central role of hormone-refractory phenotype, and other genes we identified were considered to be related to more aggressive phenotype of clinical HRPCs, and in fact, knockdown of these overexpressing genes by small interfering RNA resulted in drastic attenuation of prostate cancer cell viability. Our microarray analysis of HRPC cells should provide useful information to understand the molecular mechanism of HRPC progression and to identify molecular targets for development of HRPC treatment.

Cancer Peptide Vaccine Therapy Developed from Oncoantigens Identified through Genome-wide Expression Profile Analysis for Bladder Cancer

OBJECTIVE The field of cancer vaccine therapy is currently expected to become the fourth option in the treatment of cancer after surgery, chemotherapy and radiation therapy. We developed a novel cancer peptide vaccine therapy for bladder cancer through a genome-wide expression profile analysis. METHODS Among a number of oncoproteins that are transactivated in cancer cells, we focused on M phase phosphoprotein 1 and DEP domain containing 1, both of which are cancer-testis antigens playing critical roles in the growth of bladder cancer cells, as candidate molecules for the development of drugs for bladder cancer. In an attempt to identify the peptide epitope from these oncoantigens, we conducted a clinical trial using these peptides for patients with advanced bladder cancer. RESULTS We identified HLA-A24-restricted peptide epitopes corresponding to parts of M phase phosphoprotein 1 and DEP domain containing 1 proteins, which could induce peptide-specific cytotoxic T lymphocytes. Using these peptides, we found that M phase phosphoprotein 1- and DEP domain containing 1-derived peptide vaccines could be well tolerated without any serious adverse events, and effectively induced peptide-specific cytotoxic T lymphocytes in vivo. CONCLUSIONS The novel approach adopted in the treatment with peptide vaccines is considered to be a promising therapy for bladder cancer.

Vitamin D receptor gene polymorphisms are associated with increased risk and progression of renal cell carcinoma in a Japanese population.

Aim:  Biological and epidemiologic data suggest that 1 alpha, 25 dihydroxyvitamin D3 (1,25(OH)2D3) levels may influence development of renal cell carcinoma. The vitamin D receptor (VDR) is a crucial mediator for the cellular effects of 1,25(OH)2D3 and additionally interacts with other cell signaling pathways that influence cancer progression. VDR gene polymorphisms may play an important role in risk of incidence for various malignant tumors. This study investigated whether VDR gene polymorphisms were associated with increased risk and prognosis of renal cell carcinoma (RCC) in a Japanese population.

Outcome of Metastasectomy for Urothelial Carcinoma: A Multi-Institutional Retrospective Study in Japan

PURPOSE We determined prognostic factors associated with prolonged survival after metastasectomy for urothelial carcinoma. MATERIALS AND METHODS A total of 42 patients who underwent resection of urothelial carcinoma metastases with curative intent at 4 Japanese university hospitals were included in analysis. Of the patients 41 of 42 underwent systemic chemotherapy before and/or after metastasectomy. Overall survival was analyzed using the Kaplan-Meier method. The relationship between clinical characteristics and survival was analyzed using the log rank test. RESULTS Metastasectomy included lymph node dissection in 20 cases, pulmonary resection in 12, pelvic exenteration in 3, resection of local recurrence in 2, resection of subcutaneous metastasis in 2, liver resection in 1 and other in 2. Median overall survival was 29 months (IQR 19-80) from the initiation of treatment for metastases and 26 months (IQR 11-90) from metastasectomy. The overall 5-year survival rate after metastasectomy was 31%. On univariate analysis patients treated with metastasectomy for a solitary lung or solitary lymph node metastasis had significantly longer survival than the others who underwent metastasectomy (81 vs 19 months, log rank test p = 0.0296). CONCLUSIONS Long-term cancer control could be achieved in a subgroup of patients who undergo metastasectomy, especially those with a solitary lung or solitary lymph node metastasis.

Association of KLK5 overexpression with invasiveness of urinary bladder carcinoma cells.

Array‐based comparative genomic hybridization (array‐CGH) has powerful potential for high‐throughput identification of genetic aberrations in cell genomes. We identified high‐level amplification of kallikrein (KLK) genes, which are mapped to 19q13.3 and belong to the serine protease family, in the course of a program to screen a panel of urinary bladder carcinoma cell lines for genomic copy number aberrations using our in‐house CGH‐array. Expression levels of KLK5, ‐6, ‐8 and ‐9 were significantly increased in three cell lines with copy number gains of these KLK genes. Knockdown of these KLK transcripts by specific small interfering RNA significantly inhibited the invasion of a bladder carcinoma cell line through Matrigel in vitro. Reverse transcription–polymerase chain reaction analysis of 42 primary bladder tumor samples showed that increased expression of KLK5 was frequently observed in invasive tumors (pT2–pT4) (14.3%, 6/42) compared with superficial tumors (pTa, pT1) (0%, 0/42; P = 0.0052), and expression levels of KLK5, ‐6, ‐8 and ‐9 mRNA were higher in invasive tumors than in superficial tumors (P < 0.0001, P = 0.0043, P = 0.0790 and P = 0.0037, respectively). These observations indicate that KLK5, ‐6, ‐8 and ‐9 may be the most likely targets of the 19q13.3 amplification, and may play a crucial role in promoting cancer‐cell invasion in bladder tumor. (Cancer Sci 2007; 98: 1078–1086)

Evidence‐Based Clinical Practice Guideline for Renal Cell Carcinoma: The Japanese Urological Association 2011 update

Remarkable advances have been made in medical practice in relation to renal cell carcinoma in recent years, and a large amount of new evidence has been accumulated. In keeping with the plan at the time the first version of the “Evidence‐Based Clinical Practice Guideline for Renal Cell Carcinoma” compiled by the Japanese Urological Association was published in 2007, the Japanese Urological Association has just published a revised 2011 version. The main revisions regard the selection of treatment methods according to prognostic factors, reconsideration of treatment methods for small‐diameter renal cell carcinoma and selection criteria for medical treatment of advanced renal cell carcinoma, including selection of neoadjuvant treatment with molecular targeted medicines. This Guideline presents clinical practice methods that are thought to be the most standard methods in Japan at the present time. In this English translation of a shortened version of the original Guideline, we cited particularly important clinical questions and references.

Association of a single-nucleotide polymorphism in the immunoglobulin μ-binding protein 2 gene with immunoglobulin A nephropathy

AbstractImmunoglobulin A (IgA) nephropathy is the most common form of primary glomerulonephritis worldwide. The pathogenesis of IgA nephropathy is unknown, but it is certain that some genetic factors are involved in susceptibility to the disease. Employing a large-scale, case-control association study using gene-based single-nucleotide polymorphism (SNP) markers, we previously reported four candidate genes. We report here an additional significant association between IgA nephropathy and an SNP located in the gene encoding immunoglobulin μ-binding protein 2 (IGHMBP2) at chromosome 11q13.2–q13.4. The association (χ2 = 17.1, p=0.00003; odds ratio of 1.85 with 95% confidence interval of 1.39–2.50 in a dominant association model) was found using DNA from 465 affected individuals and 634 controls. The SNP (G34448A) caused an amino acid substitution from glutamine to lysine (E928K). As the gene product is involved in immunoglobulin-class switching and patients with the A allele revealed higher serum levels of IgA (p=0.048), the amino acid change might influence a class switch to increase serum IgA levels, resulting in a higher risk of IgA nephropathy.

Testis-specific protein on Y chromosome (TSPY) represses the activity of the androgen receptor in androgen-dependent testicular germ-cell tumors

Testis-specific protein on Y chromosome (TSPY) is an ampliconic gene on the Y chromosome, and genetic interaction with gonadoblastoma has been clinically established. However, the function of the TSPY protein remains to be characterized in physiological and pathological settings. In the present study, we observed coexpression of TSPY and the androgen receptor (AR) in testicular germ-cell tumors (TGCTs) in patients as well as in model cell lines, but such coexpression was not seen in normal testis of humans or mice. TSPY was a repressor for androgen signaling because of its trapping of cytosolic AR even in the presence of androgen. Androgen treatment stimulated cell proliferation of a TGCT model cell line, and TSPY potently attenuated androgen-dependent cell growth. Together with the finding that TSPY expression is reduced in more malignant TGCTs in vivo, the present study suggests that TSPY serves as a repressor in androgen-induced tumor development in TGCTs and raises the possibility that TSPY could be used as a clinical marker to assess the malignancy of TGCTs.

Serum levels of cardiac troponin I and other marker proteins in patients with chronic renal failure.

BackgroundSerum levels of biochemical markers for acute myocardial infarction (AMI) can be increased in patients with chronic renal failure (CRF) or skeletal muscle injury, creating diagnostic confusion. We evaluated the clinical utility of cardiac troponin I (cTnI) as a marker of AMI, particularly in patients with CRF.MethodsSubjects consisted of 59 healthy volunteers and 102 patients: 61 with CRF undergoing hemodialysis (CRF-HD), 10 with CRF under conservative therapy (CRF-CT), 21 with renal disease (RD), and 10 with muscle disease (MD). Patients with RD, CRF, and MD were evaluated to verify the absence of myocardial injury. We developed an immunoradiometric assay to measure serum cTnI using monoclonal antibodies. The lower limit of detection was 0.33 µg/l. Serum cTnI, creatine kinase (CK), CK-MB, cardiac troponin T (first-, second-, and third-generation assay: cTnT-I, cTnT-II, and cTnT-III), and cardiac myosin light chain 1 (cMLC1) were measured.ResultscTnI was not detected in healthy volunteers or patients with CRF, RD, or MD. In patients with CRF-HD, elevated levels occurred in 4.9% (3/61) for CK, 0% (0/61) for CK-MB, 39.5% (15/38) for cTnT-I, 7.3% (3/41) for cTnT-II, 13.0% (3/23) for cTnT-III, and 77.0% (47/61) for cMLC1; and in patients with MD the levels were increased in 70% (7/10) for CK, 50% (5/10) for CK-MB, 44.4% (4/9) for cTnT-I, 20% (2/10) for cTnT-II, and 50% (5/10) for cMLC1.ConclusionscTnI is a highly specific marker for AMI and is particularly useful for detecting AMI in patients with CRF or MD.

Ethnic differences in the VKORC1 gene polymorphism and an association with warfarin dosage requirements in cardiovascular surgery patients.

OBJECTIVES Vitamin K epoxide reductase (VKORC1) is the drug target for inhibition by coumarin-based anticoagulant drugs such as warfarin. Warfarin therapy has been reported as a leading cause of drug-related hospitalization and there is therefore an urgent need to develop tests for better warfarin prescription. We report here the distribution of the intron 1 -136 T>C (1173 T>C intron) polymorphism of VKORC1, previously reported to be associated with warfarin maintenance dose in Caucasians and Japanese, in several ethnic populations from Japan and Israel, and describe its significance for warfarin dosage in Japanese cardiovascular surgery patients. METHODS Subjects consisted of 132 Japanese individuals and 341 Israeli individuals from four Jewish ethnic groups (86 Ashkenazi Jews, 95 Yemenite Jews, 73 Moroccan Jews and 87 Libyan Jews). In addition, 31 Japanese patients receiving warfarin therapy after cardiovascular surgery, maintained with a target International Normalized Ratio, were studied. The genotyping for the 1173 T>C intron polymorphism of VKORC1 was determined using rapid real-time PCR. RESULTS The allele frequency of the combined VKORC1 1173 CT and CC genotypes varied among the four Israeli ethnic groups and was, on average, much higher in the Israeli (0.728) than in the Japanese population (0.152). For the Japanese cardiovascular surgery patients, the maintenance dose of warfarin was significantly larger in the combined VKORC1 1173 TC and CC genotype group than in the 1173 TT genotype group (3.6 +/- 0.5 mg vs 2.8 +/- 0.7 mg, respectively; p = 0.02). CONCLUSION The frequencies of the intron 1 VKORC1 1173 T>C SNP show significant differences between ethnic groups and are associated with warfarin dose requirements for achieving a recommended International Normalized Ratio range in Japanese cardiovascular surgery patients. This study supports the example of warfarin as an appropriate model for applying personalized medicine for anticoagulant drugs, and highlights the importance of ethnicity in pharmacogenetics.