Suppressing TGFß signaling in regenerating epithelia in an inflammatory microenvironment is sufficient to cause invasive intestinal cancer.

Genetic alterations in the TGFß signaling pathway in combination with oncogenic alterations lead to cancer development in the intestines. However, the mechanisms of TGFß signaling suppression in malignant progression of intestinal tumors have not yet been fully understood. We have examined Apc(Δ716) Tgfbr2(ΔIEC) compound mutant mice that carry mutations in Apc and Tgfbr2 genes in the intestinal epithelial cells. We found inflammatory microenvironment only in the invasive intestinal adenocarcinomas but not in noninvasive benign polyps of the same mice. We thus treated simple Tgfbr2(ΔIEC) mice with dextran sodium sulfate (DSS) that causes ulcerative colitis. Importantly, these Tgfbr2(ΔIEC) mice developed invasive colon cancer associated with chronic inflammation. We also found that TGFß signaling is suppressed in human colitis-associated colon cancer cells. In the mouse invasive tumors, macrophages infiltrated and expressed MT1-MMP, causing MMP2 activation. These results suggest that inflammatory microenvironment contributes to submucosal invasion of TGFß signaling-repressed epithelial cells through activation of MMP2. We further found that regeneration was impaired in Tgfbr2(ΔIEC) mice for intestinal mucosa damaged by DSS treatment or X-ray irradiation, resulting in the expansion of undifferentiated epithelial cell population. Moreover, organoids of intestinal epithelial cells cultured from irradiated Tgfbr2(ΔIEC) mice formed "long crypts" in Matrigel, suggesting acquisition of an invasive phenotype into the extracellular matrix. These results, taken together, indicate that a simple genetic alteration in the TGFß signaling pathway in the inflamed and regenerating intestinal mucosa can cause invasive intestinal tumors. Such a mechanism may play a role in the colon carcinogenesis associated with inflammatory bowel disease in humans.

Enhancement of tongue carcinogenesis in Hras128 transgenic rats treated with 4-nitroquinoline 1-oxide.

Transgenic rats carrying human c-Ha-ras proto-oncogene (Hras128 rats) have been shown to be highly susceptible to induction of tumors. We have found an early induction of tongue tumors in Hras128 rats treated with 4-nitroquinoline 1-oxide (4NQO). 4NQO was administered to the Hras128 and wild-type Sprague-Dawley (SD) rats for 4 and 8 weeks, respectively. The experiment was terminated at 14 (Hras128 rats) and 28 (SD rats) weeks. Either during or after treatment with 4NQO, dysplastic hyperplasia, papilloma and squamous cell carcinoma were found on the tongue of both Hras128 and wild-type rats, with a higher incidence and multiplicity in Hras128 rats. Treatment of the Hras128 rats with 4NQO significantly increased cell proliferation in the tumor compared to the control rats. In the tongue tumors of the Hras128 rats, there was a significant increase in the mRNA expression levels of cyclin D1 and COX2. To examine whether this experimental system is useful for screening of the candidate agents for cancer preventive effect, nimesulide, a selective COX2 inhibitor, was tested in the present model. Nimesulide significantly decreased total multiplicity of tongue lesions compared to the control rats. Treatment of Hras128 rats with nimesulide caused a significant decrease in the levels of mRNA expression of cyclin D1 and COX2 in the tumor. Therefore, the current 4NQO-induced Hras128 rat tongue carcinogenesis model provides a simple and rapid system for investigating carcinogenesis process and evaluating the effect of possible cancer preventive agents for human tongue cancer.

Growth inhibitory activity of ethanol extracts of Chinese and Brazilian propolis in four human colon carcinoma cell lines.

More than 300 bio-active compounds have been identified from bee propolis in various regions of the world. The objective of this study was to examine whether the ethanol extracts of Chinese and Brazilian propolis may exert anticancer activities in four human colon carcinoma cell lines, namely CaCo2, HCT116, HT29 and SW480. Propolis samples were extracted with ethanol, and the crude extracts were dissolved in dimethylsulfoxide and used for the experiments. In HCT116, HT29 and SW480 cell lines, the extracts of both Chinese and Brazilian propolis caused a marked dose-dependent growth inhibition, with IC50 values in the range of 4-41 microg/ml. In HCT116 cell line, Chinese propolis extract induced apoptosis in the cells after 72 h of treatment. In addition, Chinese propolis extract caused a dose-dependent increase in the cellular mRNA levels of p21CIP1 and p53 in the HCT116 cell line. These findings indicate that the ethanol extracts of propolis contain components that may have anticancer activity. Thus, propolis and related products may provide a novel approach to the chemoprevention and treatment of human colon carcinoma.

[Effort to improve advanced problem-based learning tutorial].

To prepare for the introduction of the advanced problem-based learning (PBL) tutorial for higher-grade students under the six-year pharmacy curriculum, a trial of the tutorial was performed in a fourth-grade class under the former four-year curriculum in 2007. A questionnaire survey conducted to identify any problems in performing the tutorial revealed: 1) the number of students in each group was too large; 2) the contents of presentations seemed to overlap due to the limited number of task cases, which forced more than one group to address a particular case; and 3) the time-line from the day of product presentation to that of periodic examination was too short to hold a sufficient group discussion. In 2008, to resolve these problems: 1) the number of groups was increased to reduce the number of students in each group; 2) new task cases were added to decrease the number of groups addressing a particular case; and 3) an adequate time period was arranged between the days of product presentation and periodic examination. The survey conducted this year demonstrated that students' learning environment had been improved by these changes in the method of performing the tutorial, but also revealed new problems such as prolongation of the time required for product presentation and the difficulty levels of task cases. In addition, the usefulness of customer satisfaction (CS) analysis was demonstrated as a result of applying it to the data analysis of evaluation performed on group presentations.

Characterization of the Kyoto circling (KCI) rat carrying a spontaneous nonsense mutation in the protocadherin 15 (Pcdh15) gene.

Protocadherin-15 (Pcdh15) plays important roles in the morphogenesis and cohesion of stereocilia bundles and in the maintenance of retinal photoreceptor cells. In humans, mutations in PCDH15 cause Usher syndrome type 1F (USH1F) and non-syndromic deafness DFNB23. In mice, repertories of Pcdh15 mutant alleles have been described as Ames waltzer mutations. For further understanding of Pcdh15 function in vivo and to develop better clinical treatment for the disabling symptoms of USH1F and DFNB23 patients, animal models suitable for clinical as well as pharmacological studies are required. Here we report the characterization of a Pcdh15 mutant allele, Kyoto circling, (Pcdh15(kci)) in the rat. Rats homozygous for Pcdh15(kci) display circling and abnormal swimming behaviors along with the lack of an auditory-evoked brainstem response at the highest intensities of acoustic stimulation. Positional cloning analysis revealed a nonsense mutation (c. 2911C>T, p. Arg971X) in the Pcdh15 gene, which is predicted to result in the truncation of the PCDH15 protein at the 9th domain of cytoplasmic cadherin domains. Histological study revealed severe defects in cochlear hair cell stereocilia, collapse of the organ of Corti, and marked reduction of ganglion cells in adult Pcdh15(kci) mutants. Severe reduction of sensory hair cells was also found in the saccular macula. Since the rat is more advantageous for clinical and pharmacological studies than the mouse, the KCI rat strain may be a better disease model for Pcdh15-deficit USH1F and DFNB23.

A set of highly informative rat simple sequence length polymorphism (SSLP) markers and genetically defined rat strains.

BACKGROUND: The National Bio Resource Project for the Rat in Japan (NBRP-Rat) is focusing on collecting, preserving and distributing various rat strains, including spontaneous mutant, transgenic, congenic, and recombinant inbred (RI) strains. To evaluate their value as models of human diseases, we are characterizing them using 109 phenotypic parameters, such as clinical measurements, internal anatomy, metabolic parameters, and behavioral tests, as part of the Rat Phenome Project. Here, we report on a set of 357 simple sequence length polymorphism (SSLP) markers and 122 rat strains, which were genotyped by the marker set. RESULTS: The SSLP markers were selected according to their distribution patterns throughout the whole rat genome with an average spacing of 7.59 Mb. The average number of informative markers between all possible pairs of strains was 259 (72.5% of 357 markers), showing their high degree of polymorphism. From the genetic profile of these rat inbred strains, we constructed a rat family tree to clarify their genetic background. CONCLUSION: These highly informative SSLP markers as well as genetically and phenotypically defined rat strains are useful for designing experiments for quantitative trait loci (QTL) analysis and to choose strategies for developing new genetic resources. The data and resources are freely available at the NBRP-Rat web site 1.

Low concentrations of propyzamide and oryzalin alter microtubule dynamics in Arabidopsis epidermal cells.

Previous studies showed that sub-micromolar concentrations of the microtubule-targeting herbicide propyzamide cause a right-handed helical arrangement of cortical microtubule arrays and left-handed twisting in elongating Arabidopsis epidermal cells. When seedlings were grown in the presence of 1-2 microM propyzamide or 50-100 nM oryzalin, we show that microtubules spent more time in a paused state in which they exhibited little net change in length. The drug treatment also resulted in slower growth and shortening velocities, increased catastrophe, and an overall decrease in microtubule turnover. A reduction in microtubule dynamic turnover may underlie the drug-induced rearrangement of cortical arrays.

A semidominant mutation in an Arabidopsis mitogen-activated protein kinase phosphatase-like gene compromises cortical microtubule organization.

Reversible protein phosphorylation regulates many cellular processes, including the dynamics and organization of the microtubule cytoskeleton, but the events mediating it are poorly understood. A semidominant phs1-1 allele of the Arabidopsis thaliana PROPYZAMIDE-HYPERSENSITIVE 1 locus exhibits phenotypes indicative of compromised cortical microtubule functions, such as left-handed helical growth of seedling roots, defective anisotropic growth at low doses of microtubule-destabilizing drugs, enhancement of the temperature-sensitive microtubule organization1-1 phenotype, and less ordered and more fragmented cortical microtubule arrays compared with the wild type. PHS1 encodes a novel protein similar to mitogen-activated protein kinase (MAPK) phosphatases. In phs1-1, a conserved Arg residue in the noncatalytic N-terminal region is exchanged with Cys, and the mutant PHS1 retained considerable phosphatase activity in vitro. In mammalian MAPK phosphatases, the corresponding region serves as a docking motif for MAPKs, and analogous Arg substitutions severely inhibit the kinase-phosphatase association. Transgenic studies indicate that the phs1-1 mutation acts dominant negatively, whereas the null phs1-2 allele is recessive embryonic lethal. We propose that the PHS1 phosphatase regulates more than one MAPK and that a subset of its target kinases is involved in the organization of cortical microtubules.

Gamma-tubulin distribution during cortical microtubule reorganization at the M/G1 interface in tobacco BY-2 cells.

Cortical microtubules are considered to regulate the direction of cellulose microfibril deposition. Despite their significant role in determining cell morphology, cortical microtubules completely disappear from the cell cortex during M phase and become reorganized at G1 phase. The mechanism by which these microtubules become properly formed again is, however, still unclear. We have proposed that the origin of cortical microtubules is on the daughter nuclear surface, but further cortical microtubule reorganization occurs at the cell cortex. Hence it is probable that the locations of microtubule organizing centers (MTOCs) are actively changing. However, the actual MTOC sites of cortical microtubules were not clearly determined. In this paper, we have examined the distribution of gamma-tubulin, one of the key molecules of MTOCs in various organisms, during cortical microtubule reorganization using both immunofluorescence and a GFP reporter system. Using a monoclonal antibody (clone G9) that recognizes highly conserved residues in y-tubulin, y-tubulin was found to be constitutively expressed and to be clearly localized to microtubule structures, such as the preprophase bands, spindles, and phragmoplasts, specific to each cell cycle stage. This distribution pattern was confirmed by the GFP reporter system. During cortical microtubule reorganization at the M to G1 transition phase, gamma-tubulin first accumulated at the daughter nuclear surfaces, and then seemed to spread onto the cell cortex along with microtubules elongating from the daughter nuclei. Based on the results, it was confirmed that daughter nuclear surfaces acted as origins of cortical microtubules, and that further reorganization occurred on the cell cortex.