Seiji Naito

Cisplatin-incorporating polymeric micelles (NC-6004) can reduce nephrotoxicity and neurotoxicity of cisplatin in rats

In spite of the clinical usefulness of cisplatin (CDDP), there are many occasions in which it is difficult to continue the administration of CDDP due to its nephrotoxicity and neurotoxicity. We examined the incorporation of CDDP into polymeric micelles to see if this allowed the resolution of these disadvantages. Cisplatin was incorporated into polymeric micelles through the polymer–metal complex formation between polyethylene glycol poly(glutamic acid) block copolymers and CDDP (NC-6004). The pharmacokinetics, pharmacodynamics, and toxicity studies of CDDP and NC-6004 were conducted in rats or mice. The particle size of NC-6004 was approximately 30 nm, with a narrow size distribution. In rats, the area under the curve and total body clearance values for NC-6004 were 65-fold and one-nineteenth the values for CDDP (P<0.001 and 0.01, respectively). In MKN-45-implanted mice, NC-6004 tended to show antitumour activity, which was comparable to or greater than that of CDDP. Histopathological and biochemical studies revealed that NC-6004 significantly inhibited the nephrotoxicity of CDDP. On the other hand, blood biochemistry revealed transient hepatotoxicity on day 7 after the administration of NC-6004. Furthermore, rats given CDDP showed a significant delay (P<0.05) in sensory nerve conduction velocity in their hind paws as compared with rats given NC-6004. Electron microscopy in rats given CDDP indicated the degeneration of the sciatic nerve, but these findings were not seen in rats given NC-6004. These results were presumably attributable to the significantly reduced accumulation of platinum in nerve tissue when NC-6004 was administered (P<0.05). NC-6004 preserved the antitumour activity of CDDP and reduced its nephrotoxicity and neurotoxicity, which would therefore seem to suggest that NC-6004 could allow the long-term administration of CDDP where caution against hepatic dysfunction must be exercised.

Preventive Effect of a Lactobacillus casei Preparation on the Recurrence of Superficial Bladder Cancer in a Double-Blind Trial

A double-blind trial was conducted in 138 patients with superficial transitional cell carcinoma of the bladder following transurethral resection to evaluate the prophylaxis of recurrence by an oral Lactobacillus casei preparation (BLP). Patients were stratified into the following 3 subgroups: (A) with primary multiple tumors; (B) with recurrent single tumors, and (C) with recurrent multiple tumors. In each group, patients were randomly allocated to receive BLP or placebo. BLP showed a better prophylactic effect in subgroups A and B than placebo, whereas no significant difference was observed in subgroup C. Cox multivariate analysis showed that the outcome with BLP was significantly better than with placebo (p = 0.01). Slight and tolerable adverse reactions occurred in 3 patients receiving BLP and in 3 of the placebo-treated patients. Oral administration of BLP was thus safe and effective for preventing recurrence of superficial bladder cancer.

Alteration in Copy Numbers of Genes as a Mechanism for Acquired Drug Resistance

Chemoresistance is a major obstacle for successful treatment of cancer. To identify regions of the genome associated with acquired resistance to therapeutic drugs, we conducted molecular cytogenetic analyses of 23 cancer-cell lines, each resistant to either camptothecin, cisplatin, etoposide (VP-16), Adriamycin, or 1-β-d-arabinofuranosylcytosine, although the parental tumor lines were not. Subtractive comparative genomic hybridization studies revealed regions of gain or loss in DNA-copy numbers that were characteristic of drug-resistant cell lines; i.e., differences from their drug-sensitive parental cell lines. Thirteen ATP-binding cassette (ABC) transporter genes [ABCA3, ABCB1 (MDR1), ABCB6, ABCB8, ABCB10, ABCB11, ABCC1 (MRP1), ABCC4, ABCC9, ABCD3, ABCD4, ABCE1, and ABCF2] were amplified among 19 of the resistant cell lines examined. Three genes encoding antiapoptotic BCL-2 proteins (BCL2L2, MCL1, and BCL2L10) were also amplified and consequently overexpressed in three of the derivative lines. Down-regulation of BCL2L2 with an antisense oligonucleotide sensitized a VP-16 resistant ovarian-cancer cell line (SKOV3/VP) to VP-16. A decrease in copy numbers of genes encoding deoxycytidine kinase, DNA topoisomerase I, and DNA topoisomerase II α reduced their expression levels in one cytosine arabinoside-resistant line, two of three camptothecin-resistant lines, and two of five VP-16-resistant cell lines, respectively. Our results indicated that changes in DNA-copy numbers of the genes mentioned can activate or down-regulate them in drug-resistant cell lines, and that such genomic alterations might be implicated in acquired chemoresistance.

A case-control study of diet and prostate cancer in Japan: possible protective effect of traditional Japanese diet.

The age‐adjusted incidence of prostate cancer is low in Japan, and it has been suggested that the traditional Japanese diet, which includes many soy products, plays a preventive role against prostate cancer. We performed a case‐control study on dietary factors and prostate cancer in order to assess the hypothesis that the traditional Japanese diet reduces the risk of prostate cancer. Four geographical areas (Ibaraki, Fukuoka, Nara, and Hokkaido) of Japan were selected for the survey. Average daily intake of food from 5 years before the diagnosis was measured by means of a semi‐quantitative food frequency questionnaire. We studied 140 cases and 140 individually age (±5 years)‐matched hospital controls for analysis. Estimates of age‐adjusted odds ratios (ORs) and linear trends were calculated by conditional logistic regression models with adjustment for cigarette smoking and total energy intake as confounding factors. Consumption of fish, all soybean products, tofu (bean curds), and natto (fermented soybeans) was associated with decreased risk. ORs of the fourth vs. first quartile and 95% confidence intervals (95%CIs) were 0.45 (0.20–1.02) for fish, 0.53 (0.24–1.14) for all soybean products, 0.47 (0.20–1.08) for tofu, and 0.25 (0.05–1.24) for natto. Consumption of fish and natto showed significantly decreasing linear trends for risk (P<0.05). Consumption of meat was significantly associated with increased risk (the OR of the second vs. first quartile was 2.19, 95%CI 1.00–4.81). Consumption of milk, fruits, all vegetables, green‐yellow vegetables, and tomatoes showed no association. Our results provide support to the hypothesis that the traditional Japanese diet, which is rich in soybean products and fish, might be protective against prostate cancer.

Habitual Intake of Lactic Acid Bacteria and Risk Reduction of Bladder Cancer

Introduction: A kind of lactic acid bacteria, Lactobacillus casei strain Shirota, shows antitumor activity in experimental animals. One clinical trial using L. casei showed a significant decrease in the recurrence of superficial bladder cancer. So, to assess the preventive effect of the intake of L. casei, widely taken as fermented milk products in Japan, against bladder cancer, we conducted a case-control study. Methods: A total of 180 cases (mean age: 67 years, SD 10) were selected from 7 hospitals, and 445 population-based controls matched by gender and age were also selected. Interviewers asked them 81 items. The conditional logistic regression was used to estimate adjusted odds ratios (OR). Results: The OR of smoking was 1.61 (95% confidence interval: 1.10–2.36). Those of previous (10–15 years ago) intake of fermented milk products were 0.46 (0.27–0.79) for 1–2 times/week and 0.61 (0.38–0.99) for 3–4 or more times/week, respectively. Conclusion: It was strongly suggested that the habitual intake of lactic acid bacteria reduces the risk of bladder cancer.

Overexpression of the wild type p73 gene in human bladder cancer.

p73, a first p53 relative, was recently identified and shown to be monoallelically expressed in a number of different human tissues. To determine the potential role of this gene in human bladder cancer, we investigated p73 expression levels, allelic expression patterns, and analysed p73 mutations in 23 unselected primary invasive bladder cancers with matched normal tissues and in seven bladder cancer cell lines. In a comparison between normal and tumor tissues using quantitative RT – PCR analysis, we found that p73 was overexpressed in 22/23 bladder cancers, sometimes as great as 20-fold. Allelic expression analysis using a C/T polymorphism in exon 2 and a newly identified T/C polymorphism in exon 5 revealed that p73 was biallelically expressed in both normal bladder and cancer tissues, suggesting that p73 is not imprinted in bladder tissue. Mutation screening of the p73 gene in bladder cancer DNAs using denaturing high-performance liquid chromatography analysis and DNA sequencing revealed no tumor-specific mutations in any coding exons of the p73 gene. These data suggest that the p73 is unlikely to be a tumor suppressor gene, but that overexpression of p73 may contribute to tumorigenesis in bladder cancer.

Usefulness of apparent diffusion coefficient map in diagnosing prostate carcinoma: Correlation with stepwise histopathology

To elucidate the performance of apparent diffusion coefficient (ADC) map in localizing prostate carcinoma (PC) using stepwise histopathology as a reference.

Prognosis of Japanese Metastatic Renal Cell Carcinoma Patients in the Cytokine Era: A Cooperative Group Report of 1463 Patients

BACKGROUND Incidence rate of renal cell carcinoma (RCC) differs among countries. The rates of Asian countries are lower than those of countries in North America or Europe but are exceptionally high in Japanese males. Approximately 30% of patients with RCC have metastasis at initial diagnosis, and another 30% have metastasis after nephrectomy. Clinical studies of risk factors in patients with metastatic RCC (mRCC) are mainly based on data from non-Asian patients. OBJECTIVES We aimed to investigate the prognosis of Japanese patients and their prognostic factors. DESIGN, SETTING, AND PARTICIPANTS The subjects of this study were 1463 patients who were clinically diagnosed with RCC with metastasis in 40 Japanese hospitals between January 1988 and November 2002. MEASUREMENTS The primary end point was overall survival calculated from first diagnosis of mRCC to death or last follow-up. We also investigated the relationship between survival and clinical features. RESULTS AND LIMITATIONS The median overall survival time was 21.4 mo. The estimated survival rates at 1, 3, 5, and 10 yr were 64.2%, 35.2%, 22.5%, and 9.1%, respectively; they contrasted with data from the United States of 54%, 19%, 10%, and 6%, respectively for the same periods. A high percentage of patients had undergone nephrectomy (80.5%) and metastasectomy (20.8%), both of which were shown to prolong survival. CONCLUSIONS The median survival time in the present study was approximately twice as long as that of previous studies from North America or Europe. Early diagnosis of metastasis, nephrectomy, metastasectomy, and cytokine-based therapy seemed to improve the prognosis of RCC patients in the present study.

Curli Fibers Are Required for Development of Biofilm Architecture in Escherichia coli K-12 and Enhance Bacterial Adherence to Human Uroepithelial Cells

Sessile bacteria show phenotypical, biochemical, and morphological differences from their planktonic counterparts. Curli, extracellular structures important for biofilm formation, are only produced at temperatures below 30 C in Escherichia coli K‐12 strains. In this report, we show that E. coli K‐12 can produce curli at 37 C when grown as a biofilm community. The curli‐expressing strain formed more biofilms on polyurethane sheets than the curli‐deficient strain under growth temperatures of both 25 C and 37 C. Curli are required for the formation of a three‐dimensional mature biofilm, with characteristic water channels and pillars of bacteria. Observations by electron microscopy revealed the presence at the surfaces of the curli‐deficient mutant in biofilm of flagella and type I pili. A wild‐type curli‐expressing E. coli strain significantly adhered to several lines of human uroepithelial cells, more so than an isogenic curli‐deficient strain. The finding that curli are expressed at 37 C in biofilm and enhance bacterial adherence to mammalian host cells suggests an important role for curli in pathogenesis.

Human homologues of the Caenorhabditis elegans cell polarity protein PAR6 as an adaptor that links the small GTPases Rac and Cdc42 to atypical protein kinase C

Asymmetric cell division in the Caenorhabditis elegans embryos requires products of par (partitioning defective) genes 1–6 and atypical protein kinase C (aPKC), whereas Cdc42 and Rac, members of the Rho family GTPases, play an essential role in cell polarity establishment in yeast and mammalian cells. However, little is known about a link between PAR proteins and the GTPases in cell polarization.