Apoptosis In CT26 Cells Research Articles

Diallyl trisulfide (DATS) inhibits mouse colon tumor in mouse CT-26 cells allograft model in vivo

Our earlier studies showed that DATS induced apoptosis in human colon cancer HT29 and colo 205 cell lines in vitro. However, there is no report to show that DATS induced apoptosis in vitro and inhibited CT26 cancer cells in vivo on a murine allograft animal model. In vitro studies, the results indicated that DATS induced morphological changes and induction of apoptosis in CT26 cells. In vivo studies, CT26 cancer cells were implanted into BALB/c mice and groups of mice were treated with vehicle, DATS (10 and 50 mg/kg of body weight). DATS were injected once per four days intraperitoneally (i.p.), with treatment starting 4 weeks prior to cells inoculation. Treatment with vehicle or with 10 and 50 mg/kg of DATS resulted in a reduction in tumor volume and weight. Tumor volume and total hemoglobin in allograft mice treated with 50 mg/kg DATS were significantly smaller than that in the control group. These findings indicated that DATS inhibits tumor growth in an allograft animal model. Thus, DATS may represent a colon cancer preventive agent and can be used in the future.

The synthesized 2-(2-fluorophenyl)-6,7-methylenedioxyquinolin-4-one (CHM-1) promoted G2/M arrest through inhibition of CDK1 and induced apoptosis through the mitochondrial-dependent pathway in CT-26 murine colorectal adenocarcinoma cells

In this study, we investigated the effects of 2-(2-fluorophenyl)-6,7-methylenedioxyquinolin-4-one (CHM-1) on cell viability, cell cycle arrest and apoptosis in CT-26 murine colorectal adenocarcinoma cells. For determining cell viability, the MTT assay was used. CHM-1 promoted G2/M arrest by PI staining and flow cytometric analysis. Apoptotic cells were evaluated by DAPI staining. We used CDK1 kinase assay, Western blot analysis and caspase activity assays for examining the CDK1 activity and proteins correlated with apoptosis and cell cycle arrest. The in vivo anti-tumor effects of CHM-1-P were evaluated in BALB/c mice inoculated with CT-26 cells orthotopic model. CHM-1 induced CT-26 cell viability inhibition and morphologic changes in a dose-dependent and time-dependent manner and the approximate IC50 was 742.36 nM. CHM-1 induced significant G2/M arrest and apoptosis in CT-26 cells. CHM-1 inhibited the CDK1 activity and decreased CDK1, Cyclin A, Cyclin B protein levels. CHM-1 induced apoptosis in CT-26 cells and promoted increasing of cytosolic cytochrome c, AIF, Bax, BAD, cleavage of pro-caspase-9, and -3. The significant reduction of caspase-9 and -3 activity and increasing the viable CT-26 cells after pretreated with caspase-9 and -3 inhibitor indicated that CHM-1-induced apoptosis was mainly mediated a mitochondria-dependent pathway. CHM-1-P improved mice survival rate, and enlargement of the spleen and liver metastasis were significantly reduced in groups treated with either 10 mg/kg and 30 mg/kg of CHM-1-P and 5-FU in comparison to these of CT-26/BALB/c mice. Taken together, CHM-1 acted against colorectal adenocarcinoma cells in vitro via G2/M arrest and apoptosis, and CHM-1-P inhibited tumor growth in vivo.

The antitumor activity of the hydrolysates of chitinous materials hydrolyzed by crude enzyme from Bacillus amyloliquefaciens V656

Chitin, colloidal chitin and water-soluble chitosan were hydrolyzed by crude enzyme solution produce by Bacillus amyloliquefaciens V656. The hydrolysates with 12 h hydrolysis contained optimal (GlcNAc) 6 and showed higher antitumor activity. Among those chitinous materials, the most effective one was the hydrolysates of water-soluble chitosan, which inhibited the growth of CT26 cells and reduced the survival rate to 34% in 1 day. Since the hydrolysate of water-soluble chitosan contained the optimal hexamer/(GlcNAc) 6 at 12 h, it is conjectured that the antitumor activity should be related to (GlcNAc) 6. This conjecture was further affirmed by experiment with pure (GlcNAc) 6. However, This phenomenon might be due to the synergistic effect of the oligomers (GlcNAc) n , n = 1–6 in the hydrolysates. The antitumor effect of the chitinous hydrolysates is worth further investigation. The aim of this study was to investigate the induced apoptosis in CT26 cells by the hydrolysates of chitinous materials. It was found that the hydrolysates (A, B and C) inhibited the survival of CT26 cells in a concentration- and time-dependent manner. The hydrolysates induced characteristic DNA fragmentation of the CT26 cells. These results suggested that the hydrolysates from chitinous materials are potent apoptosis-inducing agents for CT26 cells.

Piroxicam Treatment of Il-10-Deficient Mice Enhances Colonic Epithelial Apoptosis and Mucosal Exposure to Intestinal Bacteria

Treatment with the nonsteroidal anti-inflammatory drugs piroxicam or sulindac was recently shown to accelerate the development of colitis in interleukin (IL)-10-deficient (IL-10) mice. Although NSAIDs have been hypothesized to decrease the barrier function of the intestinal epithelium, the mechanism by which this accelerates colitis in IL-10 mice is not well understood. In this study, the effects of piroxicam on the colonic mucosa of IL-10 C57BL/6 mice were evaluated histologically. The effect of piroxicam on intestinal epithelial cells in vitro was assessed using colorimetric and fluorescent assays for cell viability and apoptotic cell death. Interactions of intestinal bacteria with the colonic mucosa were evaluated by rRNA-directed fluorescence in situ hybridization. In vivo treatment of C57BL/6 IL-10 mice with oral piroxicam markedly enhanced apoptosis of colonic epithelium and resulted in focal erosion of the mucosal surface, enhanced bacterial adhesion and invasion, and accelerated the development of colitis. In vitro, piroxicam induced apoptosis of CT26 murine intestinal epithelial cells in a dose-dependent fashion. Piroxicam-induced apoptosis of CT26 cells could not be prevented by addition of exogenous IL-10; however, IL-10 did significantly enhance their rate of proliferation. Thus, exposure to piroxicam enhances intestinal epithelial apoptosis both in vitro and in vivo and facilitates adhesion and invasion of intestinal bacteria into mucosal tissues in vivo. The role of IL-10 in this process requires further study. These studies support the hypothesis that increased exposure of mucosal cells to intestinal bacteria may lead to development of intestinal inflammation in IL-10 or other genetically susceptible individuals.

Adenovirus-mediated lymphotactin gene transfer improves therapeutic efficacy of cytosine deaminase suicide gene therapy in established murine colon carcinoma.

Lymphotactin (Ltn) is the sole member of C chemokines which attracts T cells and NK cells specially. Ltn gene was transferred in vivo to improve the antitumor efficacy of cytosine deaminase (CD) gene therapy. Upregulation of CD80 and CD54 on murine CT26 colon carcinoma cells was observed after combined transfection with adenovirus encoding CD (AdCD) and adenovirus encoding murine Ltn (AdLtn) followed by administration of 5-fluorocytosine (5FC) in vitro. AdCD/5FC treatment also increased the expression of CD95 and induced obvious apoptosis of CT26 cells. After combined treatment with AdLtn and AdCD/5FC, the pre-established murine model with subcutaneous CT26 colon carcinoma exhibited most significant tumor growth inhibition, and four of eight tumor-bearing mice were tumor free, while tumors in other mice grew more progressively. Examination of lymphocyte infiltration and cytokine gene expression in tumor tissue revealed that tumors from AdLtn/AdCD/5FC-or AdLtn-treated mice were heavily infiltrated with CD4+, CD8+ T cells and NK cells, and IL-2 and IFN-gamma mRNA expression were present in parallel with T cell and NK cell infiltration. Splenic NK and CTL activities increased significantly after the combination therapy. In vivo depletion analysis showed that NK cells, CD4+ T cells and CD8+T cells participated in the antitumor effect of the host with CD8+T cells being the main T cell subset responsible for the enhanced antitumor immune response. These findings suggested that increased immunogenicity and induction of apoptosis of the tumor cells, and efficient induction of local and systemic antitumor immunity of the host might contribute to the enhanced antitumor effects of the combined Ltn and CD suicide therapy. Gene Therapy (2000) 7, 329-338.