bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical implications of expression of ETS‐1 in relation to angiogenesis in ovarian cancers
Authors: Khatun Sufia , Fujimoto Jiro , Toyoki Hiroshi , Tamaya Teruhiko
Published: August 2005

ETS‐1 has been identified as a transcription factor involved in tumor angiogenesis, which is essential for the growth, invasion, and metastasis of solid tumors. This result prompted us to study whether ETS‐1 works as an angiogenic mediator in ovarian cancers. Immunohistochemical staining revealed that ETS‐1 was expressed in vascular endothelial cells and in cancer cells of ovarian cancers. There was a significant correlation between microvessel counts and both ETS‐1 histoscores and ets‐1 mRNA levels in ovarian cancers. Both ETS‐1 histoscores and ets‐1 mRNA levels increased with the progression of ovarian cancers. Furthermore, the 24‐month survival rate of 30 patients with high ets‐1 (high ETS‐1 histoscores and high ets‐1 mRNA levels) was 30%, while that of 30 other patients with low ets‐1 (low ETS‐1 histoscores and ets‐1 mRNA levels) was 70%. There was a significant difference between the 24‐month survival rates of the 30 patients with high ets‐1 and the 30 with low ets‐1. This indicates that ETS‐1 might act as an angiogenic mediator in, and be a prognostic factor for, ovarian cancers.
Enhanced antitumor activity of ultrasonic irradiation in the presence of new quinolone antibiotics in vitro
Authors: Huang Deqing , Okada Kyoji , Komori Chiyo , Itoi Eiji , Suzuki Toshio
Published: August 2005

To determine if there is any synergistic antitumor effect of ultrasound (US) in the presence of new quinolone (NQ) antibiotics, 0.2 mM solutions of lomefloxacin hydrochloride (LFLX), sparfloxacin (SPFX), ciprofloxacin hydrochloride (CPFX), and gatifloxacin hydrate (GFLX) were tested as sonodynamic agents against sarcoma 180 cells in vitro. After US irradiation at 2 W/cm2 for 30 and 60 s, the survival rates of tumor cells in the presence of NQ antibiotics were significantly lower than those in their absence (P<0.001). In May‐Giemsa smears, most of the tumor cells remained intact in the control group. However, in the 0.2 mM SPFX group, the tumor cells were mostly fragmented. The synergistic antitumor effect of SPFX was dose‐dependent. Furthermore, when D‐mannitol was used with SPFX, the survival rate of tumor cells after irradiation was comparable with that when SPFX alone was applied, but when L‐histidine was used concurrently, the survival rate of tumor cells was significantly higher than that when SPFX alone was applied. These findings suggest that NQ antibiotics would exhibit useful antitumor activity under US irradiation, and that generation of singlet oxygen is involved in the process of cell damage.
Molecular footprints of human lung cancer progression
Authors: Yokota Jun , Kohno Takashi
Published: August 2005

Lung cancer is the leading cause of cancer‐related death in the world. To understand the molecular processes and pathways of, and contributing factors to lung cancer progression, genetic alterations in various progression stages of lung cancer cells have been studied, since these alterations can be regarded as molecular footprints representing the individual processes of multistage lung carcinogenesis. The results indicate that defects in both the p53 and RB/p16 pathways are essential for the malignant transformation of lung epithelial cells. Several other genes, such as K‐ras, PTEN and MYO18B, are genetically altered less frequently than p53 and RB/p16 in lung cancer cells, suggesting that alterations in these genes are associated with further malignant progression or unique phenotypes in a subset of lung cancer cells. However, it is still unclear what genes control the metastatic potential of lung cancer cells. Further analyses of molecular footprints in lung cancer cells, in particular in the cells of metastatic sites, will give us valuable information to fully understand the process of lung cancer progression, and to find novel ways of controlling it. Molecular footprints at the sites of p53 mutations and p16 deletions further indicate that DNA repair activities for G:C to T:A transversion and non‐homologous end‐joining of DNA double‐strand breaks play important roles in the accumulation of genetic alterations in lung cancer cells. Thus, identification of environmental as well as genetic factors inducing or suppressing the occurrence of such alterations would be a clue to find novel ways of lung cancer prevention.
A case‐control study of diet and prostate cancer in Japan: possible protective effect of traditional Japanese diet
Authors: Sonoda Tomoko , Nagata Yoshie , Mori Mitsuru , Miyanaga Naoto , Takashima Naomi , Okumura Koji , Goto Ken , Naito Seiji , Fujimoto Kiyohide , Hirao Yoshihiro , Takahashi Atsushi , Tsukamoto Taiji , Fujioka Tomoaki , Akaza Hideyuki
Published: August 2005

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.
Overexpression of the Wilms' tumor gene WT1 in pancreatic ductal adenocarcinoma
Authors: Oji Yusuke , Nakamori Shoji , Fujikawa Masahiro , Nakatsuka Shin‐ichi , Yokota Asumi , Tatsumi Naoya , Abeno Sakie , Ikeba Ai , Takashima Satoshi , Tsujie Masanori , Yamamoto Hirofumi , Sakon Masato , Nezu Riichiro , Kawano Kiyoshi , Nishida Sumiyuki , Ikegame Kazuhiro , Kawakami Manabu , Tsuboi Akihiro , Oka Yoshihiro , Yoshikawa Kiyoshi , Aozasa Katsuyuki , Monden Morito , Sugiyama Haruo
Published: August 2005

The expression of the Wilms' tumor gene WT1 was examined by immunohistochemistry in 40 cases of pancreatic ductal adenocarcinoma. WT1 protein was expressed in 30 (75%) of the 40 pancreatic ductal adenocarcinomas, but not in the remaining 10 (25%). In normal pancreatic ductal cells, WT1 protein was undetectable. No correlations between WT1 expression and clinicopathological parameters such as age, sex, T or N stage, tumor location, and tumor differentiation were observed. Treatment with WT1 anti‐sense oligomers significantly inhibited the growth of five human pancreatic cancer cell lines, PSN1, MiaPaCa2, ASPC1, BxPC3, and PCI6, expressing the WT1 gene. These results indicate an important role of the WT1 gene in the tumorigenesis of pancreatic ductal adenocarcinoma expressing WT1 and provide a rationale for new treatment strategies to treat pancreatic ductal adenocarcinoma by targeting the WT1 gene and its product.
Suppression of metastasis by nuclear factor kB inhibitors in an in vivo lung metastasis model of chemically induced hepatocellular carcinoma
Authors: Futakuchi Mitsuru , Ogawa Kumiko , Tamano Seiko , Takahashi Seishiro , Shirai Tomoyuki
Published: August 2005

To evaluate the suppressive effects of nuclear factor kappa B (NF‐kB) inhibitors on metastasis, three agents, pentoxifylline (PTX, 0.5% in diet), N‐acetyl‐L‐cysteine (NAC, 0.5% in diet), and aspirin (ASP, 0.5% in diet) were applied in an in vivo highly metastatic rat hepatocellular carcinoma (HCC) model in F344 male rats. Administration of NF‐kB inhibitors for 8 weeks after induction of highly metastatic HCC by sequential treatment with diethylnitrosamine and N‐nitrosomorpholine did not cause any significant change in survival rate or body weight. The incidence of HCC was 100% at week 23, regardless of treatment with NF‐kB inhibitors. PTX, NAC, and ASP did not exert any significant effect on the development or differentiation of HCCs, although PTX tended to decrease the multiplicity of HCC. Although no lung metastasis was observed in the rats killed at the end of the period of carcinogen exposure, lung metastasis was found in 100% of animals in all the groups at the end of the experiment. Multiplicity of lung metastasis was significantly decreased by PTX and NAC, whereas ASP was without significant influence. The size of metastatic nodules was also significantly reduced in the PTX treatment group. Furthermore, the inhibitory k‐B (IkB) protein level, considered to be a marker for the degree of NF‐kB transcription, was significantly suppressed by PTX. mRNA expression in HCC for vascular cell adhesion molecule‐1 (VCAM‐1), which is considered to play a key role in attachment of cancer cells to the endothelium, was significantly suppressed by PTX. Among the splicing variants of VEGF, VEGF‐A120, VEGF‐A144, VEGF‐A164, and VEGF‐A188, suppressed mRNA expression of VEGF‐A188 appeared to be correlated with suppression of lung metastasis formation. In conclusion, the present study demonstrated that NF‐kB inhibitors have the potential to inhibit lung metastasis from rat HCCs in vivo, and PTX is especially promising. Its mechanism of action may involve suppression of VCAM‐1 and VEGF‐A188 production. (Cancer Sci 2004: 95: 18–24)
Expression of VEGF‐C and VEGF‐D at the invasive edge correlates with lymph node metastasis and prognosis of patients with colorectal carcinoma
Authors: Onogawa Seiji , Kitadai Yasuhiko , Tanaka Shinji , Kuwai Toshio , Kimura Shigeru , Chayama Kazuaki
Published: August 2005

Vascular endothelial growth factor (VEGF)‐C and VEGF‐D are potent lymphangiogenic factors produced by tumor and stromal cells. The purpose of this study was to determine whether expression of VEGF‐C and/or VEGF‐D correlates with clinicopathological features of human colorectal carcinoma. Expression of mRNAs for VEGF‐C, VEGF‐D, and their receptor VEGFR‐3 was examined by reverse transcription‐polymerase chain reaction (RT‐PCR) in six colon carcinoma cell lines and in fresh endoscopic biopsy specimens from 20 patients with colorectal carcinoma. Expression of VEGF‐C and VEGF‐D protein was also examined immunohistochemically in 139 archival surgical specimens of human colorectal carcinoma. Of the six cell lines, one (Colo320D) constitutively expressed VEGF‐C and four (Colo320D, DLD‐1, km12sm, km12c) constitutively expressed VEGF‐D mRNA. Expression of VEGF‐D mRNA was increased under low oxygen conditions, and all six cell lines constitutively expressed VEGF‐D mRNA under hypoxic conditions. Of the 139 specimens of human colorectal carcinoma, 65 (46.8%) showed intense VEGF‐C immunoreactivity and 41 (29.5%) showed intense VEGF‐D immunoreactivity. In 49 (75.3%) of the 65 and 20 (48.8%) of the 41 cases, heterogeneous intratumoral staining was observed for VEGF‐C and VEGF‐D, respectively, with the highest levels of expression at the invasive edges. VEGF‐C expression correlated with the depth of tumor invasion, lymphatic involvement, venous involvement, lymph node metastasis, and liver metastasis, and VEGF‐D expression correlated with the depth of tumor invasion, lymph node metastasis, and liver metastasis. No correlation was observed between VEGF‐C and VEGF‐D expression in tumors. The survival time of patients with VEGF‐C‐positive tumors was significantly shorter than that of patients with VEGF‐C‐negative tumors, and the survival time of patients with VEGF‐D‐positive tumors was significantly shorter than that of patients with VEGF‐D‐negative tumors. The survival time of patients with both VEGF‐C‐ and VEGF‐D‐positive tumors was significantly shorter than that of patients with both VEGF‐C‐and VEGF‐D‐negative tumors. These results suggest that VEGF‐C and VEGF‐D may be independent and important prognostic factors in patients with human colorectal carcinoma. (Cancer Sci 2004; 95: 32–39)
Serum phytoestrogens and prostate cancer risk in a nested case‐control study among Japanese men
Authors: Ozasa Kotaro , Nakao Masahiro , Watanabe Yoshiyuki , Hayashi Kyohei , Miki Tsuneharu , Mikami Kazuya , Mori Mitsuru , Sakauchi Fumio , Washio Masakazu , Ito Yoshinori , Suzuki Koji , Wakai Kenji , Tamakoshi Akiko
Published: August 2005

The purpose of this study was to examine whether a high serum concentration of phytoestrogens reduces the risk of prostate cancer in a case‐control study nested in a community‐based cohort in Japan (Japan Collaborative Cohort (JACC) Study). Information on lifestyles and sera of the subjects were collected in 1988–90, and they were followed up to 1999. Incident and dead cases of prostate cancer and controls were matched for study area and age. Phytoestrogens and sex hormones in sera stored at −80°C were measured in 2002. Of 14,105 male subjects of the cohort who donated their sera, 52 cases and 151 controls were identified. Three datasets were analyzed; 1) all subjects, 2) 40 cases and 101 controls after excluding subjects with low testosterone levels who were suspected of having had medical intervention, and 3) 28 cases and 69 controls with prostate specific antigen level of ∼10.0 ng/ml. The odds ratio (OR) for the highest level to the lowest was 0.38 (95% confidence interval (CI); 0.13, 1.13) for genistein, 0.41 (0.15, 1.11) for daidzein, and 0.34 (0.11, 1.10) for equol for the second dataset. Genistein and daidzein showed similar findings in the third one. Equol and equol/daidzein ratio showed consistent findings in all three datasets (OR=0.39, 95% CI; 0.13, 0.89, trend P=0.02 for the first dataset). Their effects seemed to be independent of serum sex hormones. In conclusion, serum genistein, daidzein, and equol seemed to dose‐dependently reduce prostate cancer risk. (Cancer Sci 2004; 95: 65–71)
Phase I trial of patient‐oriented vaccination in HLA‐A2‐positive patients with metastatic hormone‐refractory prostate cancer
Authors: Noguchi Masanori , Itoh Kyogo , Suekane Shigetaka , Yao Akihisa , Suetsugu Norie , Katagiri Kazuko , Yamada Akira , Yamana Hideaki , Noda Shinshi
Published: August 2005

To evaluate the safety and toxicity of peptide vaccination for patients with metastatic hormone‐refractory prostate cancer (HRPC) based on pre‐existing peptide‐specific cytotoxic T‐lymphocyte (CTL) precursors in the circulation, 10 patients positive for human leukocyte antigen (HLA)‐A2 with metastatic HRPC were enrolled in a phase I study. Peptide‐specific CTL‐precursors reactive to 16 kinds of vaccine candidates in the pre‐vaccination peripheral blood mononuclear cells (PBMCs) were measured, and patients were followed by vaccination with only positive peptides (up to 4 kinds of peptides). Serum prostate‐specific antigen (PSA) levels were monitored regularly. The peptide vaccination was safe and well tolerated with no major adverse effects. The most common toxicities were dermatologic reactions at the injection site. Increased CTL response to peptides was observed in 4 of 10 patients. Anti‐peptide IgG was also detected in post‐vaccination sera of 7 of 10 patients. One patient showed the disappearance of a pelvic bone metastasis after five vaccinations. Three patients showed a decrease of serum PSA level from the baseline after the vaccination, but no patients showed a serum PSA level decrease of ∼50%. The median survival duration of study patients was 22 months with follow‐up from 3 to 27 months. We consider that the increase in cellular and humoral immune responses, and decrease in PSA level in some patients justify further development of peptide vaccination for metastatic HRPC patients. (Cancer Sci 2004; 95: 77–84)
Antitumor activity of sugar‐modified cytosine nucleosides
Authors: Matsuda Akira , Sasaki Takuma
Published: August 2005

Nucleoside analogues which show antimetabolic activity in cells have been successfully used in the treatment of various tumors. Nucleosides such as 1‐β‐D‐arabinofuranosylcytosine (araC), 6‐mercaptopurine, fludarabine and cladribine play an important role in the treatment of leukemias, while gemcitabine, 5‐fluorouracil and its prodrugs are used extensively in the treatment of many types of solid tumors. All of these compounds are metabolized similarly to endogenous nucleosides and nucleotides. Active metabolites interfere with the de novo synthesis of nucleosides and nucleotides or inhibit the DNA chain elongation after being incorporated into the DNA strand as terminators. Furthermore, nucleoside antimetabolites incorporated into the DNA strand induce strand‐breaks and finally cause apoptosis. Nucleoside antimetabolites target one or more specific enzyme(s). The mode of inhibitory action on the target enzyme is not always similar even among nucleoside antimetabolites which have the same nucleoside base, such as araC and gemcitabine. Although both nucleosides are phosphorylated by deoxycytidine kinase and are also good substrates of cytidine deaminase, only gemcitabine shows antitumor activity against solid tumors. This suggests that differences in the pharmacological activity of these nucleoside antimetabolites may reflect different modes of action on target molecules. The design, in vitro cytotoxicity, in vivo antitumor activity, metabolism and mechanism of action of sugar‐modified cytosine nucleosides, such as (2′S)‐2′‐deoxy‐2′‐C‐methylcytidine (SMDC), 1‐(2‐deoxy‐2‐methylene‐β‐D‐erythro‐pentofuranosyl)cytosine (DMDC), 1‐(2‐C‐cyano‐2‐deoxy‐1‐β‐D‐arabino‐pentofuranosyl)cytosine (CNDAC) and 1‐(3‐C‐ethynyl‐β‐D‐ribo‐pentofuranosyl)cytosine (ECyd), developed by our groups, are discussed here.
Mutation of the von Hippel‐Lindau (VHL) gene in human colorectal carcinoma: Association with cytoplasmic accumulation of hypoxia‐inducible factor (HIF)‐1α
Authors: Kuwai Toshio , Kitadai Yasuhiko , Tanaka Shinji , Hiyama Toru , Tanimoto Keiji , Chayama Kazuaki
Published: August 2005

We screened for mutations in the von Hippel‐Lindau (VHL) tumor suppressor gene and examined the relationship of these mutations with expression of hypoxia‐inducible factor (HIF)‐1α protein in human colorectal carcinomas. DNAs were extracted from 130 paraffin‐embedded tumor specimens and subjected to poly‐merase chain reaction‐single strand conformational polymorphism (PCR‐SSCP) analysis followed by direct sequencing. We identified 13 mutations in the coding sequence of VHL, 12 of which were unique events. Three mutations were located in exon 2 and the others in exon 3. These mutations were detected in 10 of 88 (11.4%) tumors tested. Furthermore, seven of the 13 (53.8%) VHL mutants immunohistochemically showed high HIF‐1α expression. The mean percentage of cells with strong cytoplasmic HIF‐1α expression was 67.5% in tumors with VHL mutations, and this level was significantly higher than that in tumors without mutations (50.8%, P<0.05). These findings suggest that mutations in VHL may play a role in colorectal carcinoma via activation of the HIF‐related transcriptional cascade.
Heterocyclic amines: Mutagens/carcinogens produced during cooking of meat and fish
Authors: Sugimura Takashi , Wakabayashi Keiji , Nakagama Hitoshi , Nagao Minako
Published: August 2005

Research leading to the discovery of a series of mutagenic and carcinogenic heterocyclic amines (HCAs) was inspired by the idea that smoke produced during cooking of food, especially meat or fish, might be carcinogenic. More than ten kinds of HCAs, actually produced by cooking or heating of meat or fish, have now been isolated and their structures determined, most being previously unregistered compounds. They are highly mutagenic towards Salmonella typhimurium in the presence of S9 mix and are also mutagenic in vitro and in vivo toward mammalian cells. HCAs have now been chemically synthesized in quantity and subjected to long‐term animal testing. When HCAs were fed in the diet, rodents developed cancers in many organs, including the colon, breast and prostate, and one HCA produced hepatomas in monkeys. The lesions exhibited alteration in genes including Apc, β‐catenin and Ha‐ras, and these changes provide clues to the induction mechanisms. The HCAs are oxidized to hydroxyamino derivatives by cytochrome P450s, and further converted to ester forms by acetyltransferase and sulfotransferase. Eventually, they produce DNA adducts through the formation of N‐C bonds at guanine bases. There are HCA‐sensitive and resistant strains of rodents and a search for the responsible genes is now under way. While the content of HCAs in dishes consumed in ordinary life is low and not sufficient in itself to explain human cancer, the coexistence of many other mutagens/carcinogens of either autobiotic or xenobiotic type and the possibility that HCAs induce genomic instability and heightened sensitivity to tumor promoters suggest that avoidance of exposure to HCAs or reduction of HCAs’biological effects as far as possible are to be highly recommended. Usage of microwave ovens for cooking and supplementation of the diet, for example with soy‐isoflavones, which have been found to suppress the occurrence of HCA‐induced breast cancers, should be encouraged. Advice to the general public about how to reduce the carcinogenic load imposed by HCAs would be an important contribution to cancer prevention.
Molecular markers for reinforcement of histological subclassification of neuroendocrine lung tumors
Authors: Kobayashi Yasuhito , Tokuchi Yoshio , Hashimoto Takehisa , Hayashi Moriaki , Nishimura Hitoshi , Ishikawa Yuichi , Nakagawa Ken , Sato Yukitoshi , Takahashi Atsushi , Tsuchiya Eiju
Published: August 2005

The degree of malignancy of neuroendocrine lung tumors (NEs) increases in this order: from typical carcinoids (TCs) through atypical carcinoids (ACs) to large cell neuroendocrine carcinomas (LCNECs) and small cell lung carcinomas (SCLCs). However, histological classification has sometimes proved difficult. We here investigated loss of heterozygosity (LOH) using eight microsatellite markers and expression of p53, Bcl‐2 and Bax proteins using immunohistochemical methods in 57 NEs (19 TCs, 5 ACs, 14 LCNECs and 19 SCLCs), looking for objective genetic markers to distinguish between subtypes. The frequencies of LOHs on D3S1300, RBi2 and TP53, the combinations of LOH status for RBi2 and TP53, and the immunohistochemically demonstrated Bcl‐2/Bax ratios and p53‐positive rates significantly differed among histopathologically diagnosed NEs. Differentiation between TC and AC was possible with reference to LOH on D3S1300, RBi2 and TP53, and the combined LOH status on RBi2 and TP53 (i.e., both LOH(‐) versus one LOH(+)). For comparison between AC and LCNEC+SCLC, LOH on TP53 or the combination of two markers—one LOH(+) versus both LOH(+)—was applied. Furthermore, in three discordant cases of diagnoses based on histology and LOH markers, diagnoses using the latter were considered to be more probable by survival analysis. The present study indicated that assessment of LOHs using microsatellite markers could provide objective markers that can distinguish subtypes of NEs, for which histological assessment may commonly result in disagreement.
Targeted disruption of one allele of the Y‐box binding protein‐1 (YB‐1) gene in mouse embryonic stem cells and increased sensitivity to cisplatin and mitomycin C
Authors: Shibahara Kotaro , Uchiumi Takeshi , Fukuda Takao , Kura Shinobu , Tominaga Yohei , Maehara Yoshihiko , Kohno Kimitoshi , Nakabeppu Yusaku , Tsuzuki Teruhisa , Kuwano Michihiko
Published: August 2005

The eukaryotic Y‐box binding protein‐1 (YB‐1) functions in various biological processes, including transcriptional and translational control, DNA repair, drug resistance, and cell proliferation. To elucidate the physiological role of the YB‐1 protein, we disrupted one allele of mouse YB‐1 in embryonic stem (ES) cells. Northern blot analysis revealed that YB‐1+/‐ ES cells with one intact allele contain approximately one‐half the amount of mRNA detected in wild‐type (YB‐1+/+) cells. We further found that the protein level of YB‐1+/‐ cells was reduced to approximately 50–60% compared with that of YB‐1+/+ cells. However, no apparent growth difference was found between YB‐1+/‐ and YB‐1+/+ cells. YB‐1+/‐ cells showed increased sensitivity to cisplatin and mitomycin C, but not to etoposide, X‐ray or UV irradiation, as compared to YB‐1+/+ cells. YB‐1 may have the capacity to exert a protective role against cytotoxic effects of DNA damaging agents, and may be involved in certain aspects of drug resistance.
Caspase‐independent necrotic cell death induced by a radiosensitizer, 8‐nitrocaffeine
Authors: Naito Mikihiko , Hashimoto Chizuko , Masui Shigeki , Tsuruo Takashi
Published: August 2005

Molecular mechanisms of apoptosis have been extensively studied, but little is known about non‐apoptotic cell death. To study the mechanism of non‐apoptotic cell death, we searched for non‐apoptotic cell death inducers for U937 cells, which are highly sensitive to apoptosis induction by various stimuli. We found that 8‐nitrocaffeine and its analog, which are candidate radiosensitizers for cancer therapy, induced exclusively caspase‐independent necrotic cell death in cell lines such as U937, HL‐60, K562 and Jurkat. The 8‐nitrocaffeine‐induced necrotic cell death was mediated by reactive oxygen species (ROS) because (i) ROS were produced in the 8‐nitrocaffeine‐treated cells, (ii) ROS scavengers inhibited the caspase‐independent necrotic cell death induced by 8‐nitrocaffeine, and (iii) the necrotic cell death was completely suppressed in hypoxic cells. Cells selected for resistance to nitrocaffeine showed cross resistance to CH‐11, an anti‐Fas antibody, suggesting that the necrotic process plays an important role in Fas‐mediated cell death in this cell line. Since cancer cells are often derived from a selected population of cells resistant to apoptosis, inducers of necrotic cell death could be beneficial to kill cancer cells that have acquired resistance to apoptosis‐induction therapy.
Dose‐related changes of oxidative stress and cell proliferation in kidneys of male and female F344 rats exposed to potassium bromate
Authors: Umemura Takashi , Kitamura Yasuki , Kanki Keita , Maruyama Satoshi , Okazaki Kazushi , Imazawa Takayoshi , Nishimura Tetsuji , Hasegawa Ryuichi , Nishikawa Akiyoshi , Hirose Masao
Published: August 2005

It is still of importance to investigate renal carcinogenesis by potassium bromate (KBrO3), a by‐product of water disinfection by ozonation, for assessment of the risk to man. Five female F344 rats in each group were given KBrO3 at a dose of 300 mg/kg by single i.g. intubation or at a dose of 80 mg/kg by single i.p. injection, and were killed 48 h after the administration for measurements of thiobarbituric acid‐reactive substances (TBARS) and 8‐oxodeoxyguanosine (8‐oxodG) levels in the kidney. Both levels in the treated animals were significantly elevated as compared with the control values. In a second experiment, 5 male and female F344 rats in each group were administered KBrO3 at concentrations of 0, 15, 30, 60, 125, 250 and 500 ppm in the drinking water for 4 weeks. KBrO3 in the drinking water did not elevate TBARS in either sex at any of the doses examined, but 8‐oxodG formation in both sexes at 250 ppm and above was significantly higher than in the controls. Additionally, the bromodeoxyuridine‐labeling index for proximal convoluted tubules was significantly increased at 30 ppm and above in the males, and at 250 ppm and above in the females. α2u‐Globulin accumulation in the kidneys of male rats was increased with statistical significance at 125 ppm and above. These findings suggest that DNA oxidation induced by KBrO3 may occur independently of lipid peroxidation and more than 250 ppm KBrO3 in the drinking water can exert a carcinogenic effect by way of oxidative stress.
Cytochrome P450 gene expression levels in peripheral blood mononuclear cells in comparison with the liver
Authors: Furukawa Motonobu , Nishimura Masuhiro , Ogino Daisuke , Chiba Ryoji , Ikai Iwao , Ueda Nobuhiko , Naito Shinsaku , Kuribayashi Shunji , Moustafa Mohsen A. , Uchida Takafumi , Sawada Hideki , Kamataki Tetsuya , Funae Yoshihiko , Fukumoto Manabu
Published: August 2005

Cytochromes P450 (CYPs) compose a superfamily of similar proteins involved in detoxification and elimination, as well as activation of a wide variety of compounds. Most CYP family members are localized in the liver. In order to assess whether peripheral blood leukocytes (PBL) are available as a surrogate for the determination of CYP gene expression levels in the liver, we compared CYP gene expression levels in PBL with those in liver tissues from patients with hepatocellular carcinoma (HCC). We measured CYP1A1, 1A2, 1B1, 2A6, 2B6, 2C8, 2C9, 2C18, 2C19, 2D6, 2E1, 2F1, 2J2, 3A4, 3A5, 3A7, 4A11, 4B1 and CYP27 gene expressions in PBL and in the liver by real‐time reverse‐transcription (RT)‐PCR. We could detect expression of CYP1A1, 1A2, P1B1, 2A6, 2B6 and 2E1 genes in PBL and all the genes except for CYP2F1 in the liver. Although gene expression levels within each subfamily were closely correlated within PBL and within the liver, a clear correlation of gene expression levels between PBL and liver tissues was found only for CYP4B1. Although inter‐individual variation of the expression level of each CYP gene was wide, the induced level was proportional to the basal expression level. Therefore, monitoring of CYP gene expression levels in PBL, especially those of CYP4B1, could be available as a biomarker for monitoring of exposure to environmental pollutants and assessing the associated risk. Compared with non‐tumor tissue, HCC tissues tended to show overexpression of multiple CYP genes, indicating that individualized selection and more effective administration of chemotherapeutic agents could perhaps be based on the pattern of CYP overexpression.
Dependence of chemotherapy response on p53 mutation status in a panel of human cancer lines maintained in nude mice
Authors: Koike Masako , Fujita Fumiko , Komori Kinuyo , Katoh Fumitaka , Sugimoto Takuji , Sakamoto Yasuo , Matsuda Masato , Fujita Masahide
Published: August 2005

In contrast to findings in vitro, the clinical response to anticancer chemotherapy is not simply associated with the p53 mutation status. To analyze the relationship between the actual response of solid tumors with p53 mutation and other biological characteristics, we used a human cancer‐nude mouse panel of 21 lines derived from stomach, colorectal, breast, lung, and liver cancers for experimental chemotherapy. We examined the tumor growth rates of the cancer lines and the effects of nine drugs in clinical use, namely, mitomycin C (MMC), cisplatin (CDDP), nimustine hydrochloride (ACNU), irinotecan (CPT‐11), cyclophosphamide (CPA), 1‐(2‐tetrahydrofuryl)‐5‐fluorouracil (FT‐207), a 4:1 mixture of uracil and FT‐207 (UFT), 5′‐deoxy‐5‐fluorouridine (5′‐DFUR), and adriamycin (ADM), on these tumors. The chemotherapy response was expressed as the tumor growth inhibition rate (IR). The genomic DNA sequences of the p53 gene in exons 5 through 8 were analyzed in these cancer tissues, and p53 mutations were detected in 10 of the 21 cancer lines (48%). Resistance to MMC was observed in p53 mutant tumors with smaller IRs than those for wild‐type tumors (57.7% vs. 79.9%, P<0.03). No significant differences were noted with the other eight drugs. To explore the role of the p53 function in the chemotherapy response, we calculated the correlation coefficients between chemosensitivity and tumor growth rate separately in p53 mutant and wild‐type groups. In the p53 wild‐type group, we found a positive correlation for the following drugs: ADM (P<0.02), ACNU (P<0.007), CPA (P<0.011), UFT (P<0.012), and FT‐207 (P<0.02). In the p53 mutant group, only CPA (P<0.003) showed a positive correlation. The kinetics suggests that in the wild‐type tumors, DNA damage caused by anti‐cancer drugs occurs proportionally to the rate of DNA synthesis, and p53‐mediated apoptosis is subsequently induced. The low frequency of positive correlation in the p53 mutant tumors is compatible with the loss of function or malfunction of mutant p53. The present results provide kinetic evidence that p53 function affects the response to anticancer drugs. Preserved p53 function tended to confer good chemosensitivity on rapidly growing tumors. However, the p53 mutation status did not seem to be suitable for use as an exclusive indicator to predict the chemotherapy response of human cancer xenografts.
Sequential observations on the occurrence of preneoplastic and neoplastic lesions in mouse colon treated with azoxymethane and dextran sodium sulfate
Authors: Suzuki Rikako , Kohno Hiroyuki , Sugie Shigeyuki , Tanaka Takuji
Published: August 2005

Previously, we proposed a novel mouse model for colitis‐related colon carcinogenesis using azoxymethane (AOM) and dextran sodium sulfate (DSS) (Cancer Sci 2003; 94: 965–73). In the current study, sequential analysis of pathological alterations during carcinogenesis in our model was conducted to establish the influence of inflammation caused by DSS on colon carcinogenesis in this model. Male ICR mice were given a single intraperitoneal injection of AOM (10 mg/kg body weight) and given 2% (w/v) DSS in the drinking water for 7 days, starting 1 week after the AOM injection. They were sequentially sacrificed at weeks 2, 3, 4, 5, 6, 9, 12, and 14 for histopathological and immunohistochemical examinations. Colonic adenomas were found in 2 (40% incidence and 0.40±0.49 multiplicity) of 5 mice at week 3 and colon carcinomas developed in 2 (40% incidence and 2.00±3.52 multiplicity) of 5 mice at week 4. Their incidence gradually increased with time and reached 100% (6.20±2.48 multiplicity) at week 6. At week 14, the multiplicity of adenocarcinoma was 9.75±2.49 (100% incidence). In addition, colonic dysplasia was noted at all time‐points. The scores of colonic inflammation and nitrotyrosine immunohistochemistry were extremely high at early time‐points and were well correlated. Our results suggest that combined treatment of mice with AOM and DSS generates neoplasms in the colonic mucosa via dysplastic lesions induced by nitrosative stress.
Effect of hepatitis C virus infection on the risk of non‐Hodgkin's lymphoma: A meta‐analysis of epidemiological studies
Authors: Matsuo Keitaro , Kusano Aaron , Sugumar Aravind , Nakamura Shigeo , Tajima Kazuo , Mueller Nancy E.
Published: August 2005

Although a high prevalence of hepatitis C virus (HCV) infection among non‐Hodgkin's lymphoma (NHL) patients had been reported, subsequent epidemiological studies conducted to examine a causal association between HCV and NHL have provided inconsistent results across studies. A strikingly positive association has been reported primarily from Italy and Japan, while no association was found in other regions of the world. To clarify the association between HCV and NHL, we conducted a systematic literature review. Eligible study designs were nested case‐control studies, population‐based case‐control studies, and hospital‐based case‐control studies using non‐cancer subjects as controls. The studies published through January 1991 to August 2003 were searched through Medline. Ultimately, 23 studies with 4049 NHL patients and 1,813,480 controls were identified. Summary statistics were crude odds ratios (ORs) comparing the anti‐HCV se‐ropositive and seronegative subjects. As we identified heterogeneity between studies, summary statistics were calculated based on a random‐effect model. We did not find any evidence of publication bias. The major sources of variation were the use of blood donor controls and year of publication. The summary OR for NHL was 5.70 (95% confidence interval (Cl), 4.09–7.96, P<0.001). The subgroup analysis by phenotype showed a similar trend for B‐cell (5.04, 95% Cl: 3.59–7.06) and T‐NHL (2.51, 95% Cl: 1.39–4.56). In conclusion, we found a strongly positive association between anti‐HCV seropositive test subjects and risk of NHL. Further biological studies examining this association are warranted.
Characterizing the role of enterohepatic recycling in the interactions between mycophenolate mofetil and calcineurin inhibitors in renal transplant patients by pharmacokinetic modelling
Authors: Cremers Serge , Schoemaker Rik , Scholten Eduard , Den Hartigh Jan , König‐Quartel Jacqueline , Van Kan Eric , Paul Leendert , De Fijter Johan
Published: August 2005

Background

Controversy remains about the interaction between mycophenolate mofetil (MMF) and the calcineurin inhibitors cyclosporin (CsA) and tacrolimus (TACR). The need to double the dose of MMF in case of CsA co‐administration to achieve the same mycophenolic acid (MPA) levels as in TACR co‐administration, has been attributed to either inhibition by CsA of the enterohepatic cycle, or an inhibition of glucuronidation to mycophenolate glucuronide (MPAG) by TACR. We explored these interactions clinically in 64 kidney transplant patients.

Methods

Plasma MPA/MPAG curves were determined during the first year post transplantation. Using nonlinear mixed effect modelling, MPA/MPAG data were fitted to a four‐compartment  model,  in  which  a  rate  constant  describing  transfer  from  the  fourth  to the first compartment (k41), and therefore enterohepatic recycling, could be introduced.

Results

MPA and MPAG plasma concentrations were adequately described by a four‐compartment model, which was significantly improved by introduction of k41 in case of TACR co‐administration (minimum value of the objective function decreased by 181 points, P < 0.0001). Using this model, no statistically significant difference was observed in clearance of MPA between TACR and CsA co‐administration (11.9 and 14.1 l h−1, respectively). Total clearance of MPAG was lower in case of CsA co‐administration (1.45 and 0.92 l h−1, respectively), while there was no difference in renal clearance of MPAG (1.09 and 0.92 l h−1, respectively).

Conclusions

Our study supplies supportive clinical evidence that inhibition of the enterohepatic cycle in case of CsA co‐administration explains some of the differences observed in PK of MMF when co‐administered with either TACR or CsA. This finding may have clinical consequences for the immunosuppressive management of kidney transplant patients.
Pharmocokinetics and pharmacodynamics of single‐dose triazolam: electroencephalography compared with the Digit‐Symbol Substitution Test
Authors: Greenblatt David J. , Gan Lu , Harmatz Jerold S. , Shader Richard I.
Published: August 2005

Aims

To investigate whether the electroencephalogram (EEG) directly reflects the CNS effects of benzodiazepines by evaluating the relation of the EEG to plasma drug concentrations and to Digit‐Symbol Substitution Test (DSST) scores after a single dose of triazolam, a representative benzodiazepine agonist.

Methods

Thirteen healthy male subjects were given 0.375 mg triazolam or placebo in a double‐blind crossover study. Plasma samples were collected during 8 h after dosage. Pharmacodynamic effects were measured by DSST and EEG at corresponding times.

Results

Pharmacokinetic parameters for triazolam were consistent with established values. Compared with placebo, triazolam significantly impaired psychomotor performance on the DSST (P < 0.001) and increased beta amplitude on the EEG (P < 0.002). DSST and EEG changes both closely tracked changes in plasma concentrations over time. The changes for the two measures were highly correlated with each other (r =–0.94, P < 0.001) based on aggregate values at individual time points. However, the variations in area under the curve of pharmacodynamic effect vs. time (AUCeffect) measured by either method did not reflect the variations in plasma AUC across individuals. The individual variability in AUCeffect from the EEG was similar to that measured by the DSST.

Conclusions

Both the EEG and the DSST reflect the central benzodiazepine agonist effects of triazolam. Intrinsic variability in both measures is similar.
Nutrient limitation and enzyme activities during litter decomposition of nine wetland species in relation to litter N : P ratios
Authors: GÜSEWELL S. , FREEMAN C.
Published: August 2005

Litter decomposition can be limited by nitrogen or phosphorus, but conditions under which either nutrient is limiting remain uncertain. We investigated whether this depends on nutrient limitation during plant growth, on N : P ratios of the litter, or on activities of C‐, N‐ and P‐mineralizing enzymes.

Nine herbaceous species were grown at N : P supply ratios (N : Ps) of 5–160 (mass‐based). Fresh leaf litter was incubated in the laboratory for 5–10 weeks, partly with N or P fertilization, to determine mass loss and activities of extracellular enzymes.

Both plant growth and litter decomposition were N‐limited for plants grown at N : Ps < 20, and P‐limited for those grown at N : Ps ≥ 40. Litter N : P ratios varied widely among species and did not predict which nutrient limited decomposition, except that litter with N : P > 22 always had P‐limited decomposition.

The activities of β‐glucosidase, chitobiase and phosphatase differed widely among species but were poorly related to litter nutrient concentrations and mass loss. Within some species, phosphatase activity increased towards high litter N : P ratios, suggesting P limitation of decomposers.

We conclude that there is no unique critical N : P ratio discriminating between N‐ and P‐limited decomposition because this critical N : P ratio is species‐dependent and may also depend on the physical conditions under which plants were grown.
Responses to stress of Caenorhabditis elegans populations with different reproductive strategies
Authors: ÁLVAREZ O. ALDA , JAGER T. , KOOIJMAN S. A. L. M. , KAMMENGA J. E.
Published: August 2005

Hermaphroditic and gonochoric reproduction are essentially different reproductive strategies that may lead to diverging population responses to adverse environmental conditions. Each strategy implies different physiological mechanisms, which affect life‐history traits and represent different ways of dealing with stress.

We studied the performance of hermaphroditic vs gonochoric strains in the nematode Caenorhabditis elegans exposed to cadmium stress at the individual and population level.

Under control conditions, the gonochoric strain started reproduction earlier than the hermaphroditic strain at a smaller size. This was due to an earlier switch from sperm to oocyte production triggered by male sperm availability. Under cadmium stress hermaphrodites showed a decrease in the size at onset of reproduction, presumably as a strategy to maintain a high population growth rate. In contrast the body size of gonochoric nematodes was not affected.

A process‐based model (DEBtox) was used as a tool for analysing life‐history data and calculating population growth rates. The model fitted the data well using physiologically relevant parameters such as ageing, survival or reproduction related parameters. The simultaneous fit of all life‐history traits was used to obtain populations growth rate estimates.

The differences between the two C. elegans strains were reflected at the population level. Lower population growth rates, as calculated by DEBtox, were found in the gonochoric strain, largely determined by the proportion of males in the offspring.

From the overall results we suggest that the differences found between both populations are due to the reproductive strategy. Under control conditions, CB strain (with gonochoric reproduction) does not favour population growth rates in the short term due to faster ageing and copulation costs on survival. Furthermore, in response to stress this strain also showed lower performance than the N2 hermaphroditic strain, mainly due to a higher sensitivity of survival to the stressor.
Does water transport scale universally with tree size?
Authors: MEINZER F. C. , BOND B. J. , WARREN J. M. , WOODRUFF D. R.
Published: August 2005

We employed standardized measurement techniques and protocols to describe the size dependence of whole‐tree water use and cross‐sectional area of conducting xylem (sapwood) among several species of angiosperms and conifers.

The results were not inconsistent with previously proposed 3/4‐power scaling of water transport with estimated above‐ground biomass. However, for a given size, angiosperms transported considerably greater quantities of water than conifers.

In the angiosperms studied, the scaling of water transport with sapwood area, stem diameter and above‐ground biomass was best described by sigmoid functions rather than a power function, consistent with the previously reported size dependence of other processes such as growth.

At least three distinct species groupings for relationships between sapwood area and stem basal area were observed. Scaling of sapwood area with stem radius was well described by a power function of the formY = Y0Xb. However, exponents obtained for two of the three species groups differed significantly from a recently proposed theoretical value of 2·33.
Soil organic matter and litter chemistry response to experimental N deposition in northern temperate deciduous forest ecosystems
Authors: Gallo M. E. , Lauber C. L. , Cabaniss S. E. , Waldrop M. P. , Sinsabaugh R. L. , Zak D. R.
Published: August 2005

The effects of atmospheric nitrogen (N) deposition on organic matter decomposition vary with the biochemical characteristics of plant litter. At the ecosystem‐scale, net effects are difficult to predict because various soil organic matter (SOM) fractions may respond differentially. We investigated the relationship between SOM chemistry and microbial activity in three northern deciduous forest ecosystems that have been subjected to experimental N addition for 2 years. Extractable dissolved organic carbon (DOC), DOC aromaticity, C : N ratio, and functional group distribution, measured by Fourier transform infrared spectra (FTIR), were analyzed for litter and SOM. The largest biochemical changes were found in the sugar maple–basswood (SMBW) and black oak–white oak (BOWO) ecosystems. SMBW litter from the N addition treatment had less aromaticity, higher C : N ratios, and lower saturated carbon, lower carbonyl carbon, and higher carboxylates than controls; BOWO litter showed opposite trends, except for carbonyl and carboxylate contents. Litter from the sugar maple–red oak (SMRO) ecosystem had a lower C : N ratio, but no change in DOC aromaticity. For SOM, the C : N ratio increased with N addition in SMBW and SMRO ecosystems, but decreased in BOWO; N addition did not affect the aromaticity of DOC extracted from mineral soil. All ecosystems showed increases in extractable DOC from both litter and soil in response to N treatment. The biochemical changes are consistent with the divergent microbial responses observed in these systems. Extracellular oxidative enzyme activity has declined in the BOWO and SMRO ecosystems while activity in the SMBW ecosystem, particularly in the litter horizon, has increased. In all systems, enzyme activities associated with the hydrolysis and oxidation of polysaccharides have increased. At the ecosystem scale, the biochemical characteristics of the dominant litter appear to modulate the effects of N deposition on organic matter dynamics.