The novel microtubule-interfering agent TZT-1027 enhances the anticancer effect of radiation in vitro and in vivo.

TZT-1027 is a novel anticancer agent that inhibits microtubule polymerisation and manifests potent antitumour activity in preclinical models. We have examined the effect of TZT-1027 on cell cycle progression as well as the anticancer activity of this drug both in vitro and in vivo. With the use of tsFT210 cells, which express a temperature-sensitive mutant of Cdc2, we found that TZT-1027 arrests cell cycle progression in mitosis, the phase of the cell cycle most sensitive to radiation. A clonogenic assay indeed revealed that TZT-1027 increased the sensitivity of H460 cells to gamma-radiation, with a dose enhancement factor of 1.2. Furthermore, TZT-1027 increased the radiosensitivity of H460 and A549 cells in nude mice, as revealed by a marked delay in tumour growth and an enhancement factor of 3.0 and 2.2, respectively. TZT-1027 also potentiated the induction of apoptosis in H460 cells by radiation both in vitro and in vivo. Histological evaluation of H460 tumours revealed that TZT-1027 induced morphological damage to the vascular endothelium followed by extensive central tumour necrosis. Our results thus suggest that TZT-1027 enhances the antitumour effect of ionising radiation, and that this action is attributable in part to potentiation of apoptosis induction and to an antivascular effect. Combined treatment with TZT-1027 and radiation therefore warrants investigation in clinical trials as a potential anticancer strategy.

Peroxisome proliferator-activated receptor gamma ligand prevents the development of chronic pancreatitis through modulating NF-kappaB-dependent proinflammatory cytokine production and pancreatic stellate cell activation.

PURPOSE: Thiazolidinedione derivatives (TZDs) are known to be ligands of peroxisome proliferator-activated receptor gamma (PPARgamma). In this study, we investigated the effect of a TZD, troglitazone, on inflammation and fibrogenesis in the pancreas of an experimental model of chronic pancreatitis. MATERIAL AND METHODS: Male WBN/Kob rats with spontaneous chronic pancreatitis were fed rat chow containing 0.2% troglitazone from 1 to 4 months of age. Immunohistochemical studies of rat pancreas were carried out with monoclonal mouse antibody against human alpha-smooth muscle actin (alpha-SMA) or rabbit polyclonal antibody against collagen type I, collagen type III, or fibronectin. Cytokine production was measured by enzyme-linked immunosorbent assay. The inhibitory action of troglitazone on nuclear factor-kappaB (NF-kappaB) binding activity in activated macrophages was also investigated. RESULTS: Long-term administration of troglitazone reduced inflammatory cell infiltration and fibrosis in the pancreas of WBN/Kob rats, and expression of alpha-SMA, procollagen I, III, and fibronectin was significantly reduced by troglitazone. The increase in TNF-alpha production by activated macrophages was significantly decreased by troglitazone. Peritoneal macrophages isolated from WBN/Kob rats produced a large amount of TNF-alpha, whereas those from troglitazone-treated WBN/Kob rats produced only a marginal amount of TNF-alpha. Lipopolysaccharide-induced NF-kappaB binding activity in peritoneal macrophages was also significantly reduced by troglitazone. CONCLUSIONS: Troglitazone prevented the progression of chronic pancreatitis via inhibition of ECM synthesis and proinflammatory cytokine production mediated by the inhibition of NF-kappaB activity.

CB6F1-rasH2 mouse: overview of available data.

This article presents data from short-term carcinogenicity studies of compounds tested in the CB6F1-rasH2 transgenic mouse as part of the International Life Sciences Institutes' (ILSI) Health and Environmental Sciences' (HESI) Alternative to Carcinogenicity Testing (ACT) project. Additionally, data from other studies that were not conducted as part of the ILSI program, but used comparable or slightly modified protocols, are included here. A significant number (3 of 4) of the genotoxic carcinogens tested were positive in the rasH2 mouse; the other compound was equivocally positive. The positive control, N-Methyl-N-nitrosurea (MNU), gave reproducible responses across all participating laboratories with tumors noted at multiple sites in the animal. The immunosuppressive human carcinogen. Cyclosporin A, was equivocal. Two hormones that are human tumorigens. Diethylstilbestrol and 17beta-Estradiol, gave positive and negative results, respectively. Of the twelve additional compounds tested that are classified as non-genotoxic rodent carcinogens and putative human non-carcinogens, only the two peroxisome proliferators (clofibrate and diethylhexylphthalate(DEHP)) produced a positive response (liver effects). The three non-genotoxic non-carcinogens that were tested also gave negative responses in the rasH2 model. This result provides confidence that the model is likely to have a low false-positive rate.

Testicular toxicity in F344 rats by aminophenylnorharman, formed from norharman and aniline.

9-(4'-Aminophenyl)-9H-pyrido[3,4-b]indole [aminophenylnorharman (APNH)] is a novel mutagenic heterocyclic amine, produced by the reaction of norharman with aniline in the presence of S9 mix. In the present study, the acute toxicity of this compound was investigated in male F344 rats. Ten-week-old animals were treated with a single intragastric injection of APNH at doses of 45 or 90 mg/kg body wt and euthanized 1, 3, or 6 days afterward. When APNH was administered at a dose of 90 mg/kg, vacuolation of Sertoli cells in the testis was seen at 1 day after treatment. The testicular damage had markedly progressed by day 6, with multinucleated giant cells and loss of round spermatids in the seminiferous tubules observed in groups 1 and 2 of the four histological categories of spermatogenesis. Numbers of spermatogonia were also decreased by APNH treatment. No toxic changes were observed in Leydig cells under these conditions and serum follicle-stimulating hormone and luteinizing hormone concentrations were also unchanged from control values. Such severe testicular damage was not observed at any time point at the 45 mg/kg dose level of APNH. Moreover, neither norharman nor aniline alone exerted acute testicular toxicity at doses equivalent to 90 mg/kg of APNH. In addition to the testicular lesions, erosive changes of urinary bladder, thymic atrophy, and panmyelophthisis were evident in rats given APNH at 90 mg/kg.

Changes in the levels of mRNAs for putative cell growth-related genes in the albedo and flavedo during citrus fruit development.

Changes in mRNA levels for the seven gene homologues to endoxyloglucan transferase-related protein, expansin, extensin, ß-1,3 glucanase, glycine-rich protein, pectinacetylesterase and pectinesterase, which were obtained by random sequencing studies, were investigated in relation to rind development in citrus (Citrus unshiu Marc.) fruit. Expression patterns in the albedo and flavedo were classified into four types: Type-I, transcript levels low in early fruit development but increased at the ripening stage; Type-II, transcript levels high until mid-development and then decreased towards ripening; Type-III, detectable transcript limited to fruitlets at 26 days after flowering (DAF); Type-IV, ubiquitous during the development. Based on the expression patterns, we discuss the possible roles of these genes in rind development.

Rectal absorption of [Bis (acetato) ammine dichloro (cyclohexylamine) platinum(IV)] (BMS-182751), a new anti-tumor agent, in rats.

The rectal absorption of a platinum anti-tumor agent, [bis (acetato) ammine dichloro (cyclohexylamine) platinum(IV)] (BMS-182751), was investigated in rats. BMS-182751 was co-ground with various carriers to improve its poor aqueous solubility. The highest drug dissolution was observed for the co-ground mixture of BMS-182751 and low molecular (LM) gelatin (1:9, w/w), followed by beta-cyclodextrin and polyvinylpyrrolidone. The influence of a suppository base or additive on the rectal absorption of BMS-182751 in the drug state of crystalline powder or co-ground mixture was examined in vitro using excised rat rectum. A macrogol base gave much higher BMS-182751 permeation across the rat rectum than that from a Pharmasol base. The addition of sodium caprylate or caprylic acid to the macrogol base markedly enhanced the drug permeation, and a 3% addition of sodium caprylate to the base afforded maximum drug permeation. Two rectal formulations, the co-ground mixture with LM-gelatin plus 3% sodium caprylate in macrogol and the crystalline drug alone plus 3% sodium caprylate in macrogol, as well as an oral aqueous drug suspension, were administered to rats. The Cmax and AUC0-24h values for platinum from the former suppository were 5.1- and 4.1-fold greater than those from the oral suspension, respectively. The values from the latter suppository were almost comparable to those from the suspension. These results suggest that the suppository may provide a promising therapeutic means for cancer treatment using this platinum agent.

Characterization of gene repertoires at mature stage of citrus fruits through random sequencing and analysis of redundant metallothionein-like genes expressed during fruit development.

We carried out a random sequencing of cDNA library derived from mature citrus fruit (Citrus unshiu Marc.) for identifying the gene repertoires expressed at the mature stage. Among 297 clones analyzed, 195 cDNA clones (65.7%) were putatively identified to previously characterized genes with optimized (OPT) scores of >/=200 through a homology search to DNA database, whereas 102 clones (34.3%) resulted in low OPT scores (<200) and did not show any significant sequence identity with previously published genes. Among them, clones homologous to metallothionein (MT)-like genes appeared 62 times, being mostly redundant, and accounting for about 20.9% of the total 297 clones. To gain a better understanding of the MT-like genes, two types of cDNA clones were isolated. One clone (CitMT36) resembled the type 2 MT gene containing Cys-X-Cys motifs in both N- and C-terminal, but the consensus sequence in the N-terminal domain, Cys-Cys and Cys-X-X-Cys was modified in CitMT36 to X-Cys and Cys-X-X-X, respectively. We suggest that these form a 'novel type 2' group of MT-like clones. The other clone (CitMT45) showed homology to type 3 MT-like genes, which have been found in mostly fruit tissues so far. By Southern blot analysis, both clones showed one or two bands, suggesting that both CitMT36 and CitMT45 are present in single or a few copies in the citrus genome. Transcripts of CitMT36 were evenly detected in all tissues examined, whereas those of CitMT45 were detected primarily in fruit during the developmental phase. Neither of the MT-like genes was induced in leaves by Zn and Cu. Collectively, MT-like genes from citrus would be regulated differentially depending on the fruit developmental stage and organs, indicating a change in their expression under the different physiological and molecular environment of fruit cells.

Effects of centrally affecting drugs on the diuretic and antidiuretic actions of intracerebroventricular prostaglandin E2.

Effects of centrally affecting drugs on the diuretic and antidiuretic actions of intracerebroventricularly (i.c.v.) injected prostaglandin (PG) E2 in ethanol-anaesthetized rats were studied. PGE2, when injected i.c.v. at a dose of 1 nmole, produced diuresis followed by antidiuresis. When morphine (0.1 mM) was perfused i.c.v., urine outflow decreased and neither diuretic nor antidiuretic effects of i.c.v. PGE2 was apparent. The perfusions with picrotoxin, gamma-aminobutyric acid and L-glutamate inhibited either the diuretic or the antidiuretic effect of PGE2. On the other hand, when pentobarbital, diazepam, isoniazid and strychnine were perfused i.c.v., the diuretic action of PGE2 was diminished and antidiuresis in response to PGE2 remained unchanged. These results suggested that the diuretic and antidiuretic effects of PGE2 could be separated. The developed of the diuretic effect of PGE2 was completely blocked by amitriptyline and antidiuresis was increased. In rats pretreated i.c.v. with reserpine, the diuretic effect of PGE2 was prolonged and antidiuresis in response to PGE2 was not observed. An antidiuretic action of i.c.v. norepinephrine was not varied by reserpine. Mechanisms for both effects of PGE2 are discussed.