The chemopreventive agent ursodeoxycholic acid inhibits proliferation of colon carcinoma cells by suppressing c-Myc expression.

Ursodeoxycholic acid (UDCA) can prevent chemical and colitis-associated colon carcinogenesis by unknown mechanism(s). One of the processes underlying the chemopreventive action could be the inhibition of proliferation by UDCA. To clarify the antiproliferative mechanism of UDCA, we used p53 wt colon carcinoma cell lines HCT8 and HCT116.

Mismatch repair system decreases cell survival by stabilizing the tetraploid G1 arrest in response to SN-38.

The role of the mismatch repair (MMR) system in correcting base-base mismatches is well established; its involvement in the response to DNA double strand breaks, however, is less clear. We investigated the influence of the essential component of MMR, the hMLH1 protein, on the cellular response to DNA-double strand breaks induced by treatment with SN-38, the active metabolite of topoisomerase I inhibitor irinotecan, in a strictly isogenic cell system (p53(wt), hMLH1(+)/p53(wt), hMLH1(-)). By using hMLH1 expressing clones or cells transduced with the hMLH1-expressing adenovirus as well as siRNA technology, we show that in response to SN-38-induced DNA damage the MMR proficient (MMR(+)) cells make: (i) a stronger G2/M arrest, (ii) a subsequent longer tetraploid G1 arrest, (iii) a stronger activation of Chk1 and Chk2 kinases than the MMR deficient (MMR(-)) counterparts.

DNA damage-induced expression of p53 suppresses mitotic checkpoint kinase hMps1: the lack of this suppression in p53MUT cells contributes to apoptosis.

DNA damage induced by the topoisomerase I inhibitor irinotecan (CPT-11) triggers in p53(WT) colorectal carcinoma cells a long term cell cycle arrest and in p53MUT cells a transient arrest followed by apoptosis (Magrini, R., Bhonde, M. R.

Prevention of colitis-associated carcinogenesis in a mouse model by diet supplementation with ursodeoxycholic acid.

Bile acids in the intestinal lumen contribute to the homeostatic regulation of proliferation and death of the colonic epithelial cells: Deoxycholic acid (DCA) appears to enhance and ursodeoxycholic acid (UDCA) to attenuate the process of chemically induced carcinogenesis. We studied the effects of UDCA on colitis-related colorectal carcinogenesis. Three groups of 25 mice were given 0.

Prognostic value of multimarker analysis in stage III colorectal cancer: one step forward towards an individualized therapy decision.

Background: Recently, we have analyzed new prognostic markers in colorectal cancer including neuroendocrine differentiation, overexpression of the sialyl-Lex antigen, overexpression of the peripheral benzodiazepine receptor (PBR), BAX protein expression and p53 mutational status. The predictive power of all markers in combination has not yet been evaluated.

Patients And Methods: Between 1989 and 1991, 48 consecutive patients underwent surgery for stage III colorectal cancer at our hospital.

The broad-range cyclin-dependent kinase inhibitor UCN-01 induces apoptosis in colon carcinoma cells through transcriptional suppression of the Bcl-x(L) protein.

The broad-range cyclin-dependent kinase inhibitor 7-hydroxystaurosporine (UCN-01) is known to induce both a G1 cell cycle arrest and apoptosis. The mechanism of UCN-01-induced apoptosis is largely unknown. We analysed the mechanism of cytotoxicity of UCN-01 in four established colon carcinoma cell lines.

Role of site-specific promoter hypomethylation in aberrant MUC2 mucin expression in mucinous gastric carcinomas.

In the present work we investigated the methylation levels of mucin gene (MUC)2 promoter region in normal gastric mucosa and mucinous gastric carcinoma in order to access if the observed de novo expression of the intestinal mucin MUC2 in mucinous gastric carcinoma is associated with changes in MUC2 promoter methylation status. The results obtained by methylation-sensitive single nucleotide primer extension suggest that MUC2 expression in gastric cells is regulated by promoter methylation and further indicate that two specific cytosine guaine dinucleotide (CpG) sites may play a particularly important regulatory role.

Cellular effects of CPT-11 on colon carcinoma cells: dependence on p53 and hMLH1 status.

Irinotecan (CPT-11), a recently introduced component of a standard chemotherapy for colorectal cancer, induces in colon cancer cell lines in vitro cell cycle arrest and apoptosis. Since sporadic colon carcinomas exhibit in 50-60% mutations in the p53 gene and in 10-15% an MSI phenotype due in the great majority of the cases to hMLH1 inactivation, we investigated how these lesions influence the cellular effects of CPT-11 by using colorectal carcinoma cell line HCT116 (which has the genotype p53(+/+),hMLH1(-)) and 2 derivative cell lines with the genotypes p53(+/+),hMLH1(+) and p53(-/-),hMLH1(-). CPT-11 treatment induced G2/M arrest in all 3 cell lines within 48 hr.