Effect of low concentrations of p,p′- dichlorodipheny ltrichloroethane on proliferation and apoptosis of coIorectal adenocarcinoma SW620 cells / 中国药理学与毒理学杂志

OBJECTIVE To investigate the effect and mechanism of low concentrations of p,p′-dichlorodiphenyltrichloroethane (p,p′-DDT) on colorectal adenocarcinoma SW620 cell proliferation and apoptosis. METHODS SW620 cells were exposed to low concentrations of p, p′-DDT ranging from 1×10-12 to 1×10-6 mol.L-1 for 48 and 96 h. MTT assay was employed to examine the effect of p,p′-DDT on SW620 cell viability. Different cell stages of cycle and apoptosis rate were determined by flow cytometry after SW620 cells were exposed to 1×10-10 , 1×10-9 and 1×10-8 mol.L-1 for 96 h. Western blotting was used to determine the protein expression of Wnt/ β-catenin signaling components 〔β-catenin, phospho-β-catenin and phospho-glycogen synthase kinase ( GSK) 3β〕, their downstream target proteins ( c-Myc and cyclin D1)and apoptosis related proteins (Bcl-2, Bax, procaspase 8 and procaspase 3). RESULTS The viability of colorectal adenocarcinoma SW620 cells was significantly increased after exposure to low concentrations of p,p′-DDT ranging from 1×10-12 to 1×10-7 mol.L-1 for 96 h. p,p′-DDT 1×10-10 , 1×10-9 and 1×10-8 mol.L-1 exposure led to a decreased percentage of SW620 cells in G1 stage(P<0.01) along with an increased percentage of cells in S stage(P<0.01). Meanwhile, the apoptosis rate was signifi-cantly decreased compared with control group ( P < 0. 01). Exposure to p, p′-DDT from 1 × 10-10 to 1×10-8 mol.L-1 induced upregulation of phospho-GSK3β ( Ser9), β-catenin, c-Myc and cyclin D1 in SW620 cells( P <0.01). Moreover, apoptosis related proteins Bcl-2, procaspase 8 and procaspase 3 were unregulated(P<0.01), and Bax level and caspase 3 activity were decreased in p,p′-DDT-stimulated cells(P < 0.01). CONCLUSION Low concentrations of p, p′-DDT exposure activates Wnt/ β-catenin signaling and affects apoptosis-related proteins, which may be involved in p,p′-DDT-induced cell prolifer-ation as well as suppression of cell apoptosis in SW620 cells.

SYNCHRONOUS MULTIPLE PRIMARY CANCER AND ADENOMA OF LARGE INTESTINES / 中国癌症杂志

PURPOSE To discuss induction and relation of synchronous multiple primary cancer to adenoma of large intestines. METHODS Continuous observation of resectable and pathologically proved cancer of large intestines of 166 cases. RESULTS We discovered 8 cases (4. 8%) of synchronous multiple primary cancer of large interstines. 43 cases of single primary cancer of concomitant adenoma (27. 7%). The 4 cases of synchronous cancer had merged adenoma (50%). The 4 cases of synchronous cancer had concomitant adenoma of 14 sites. Of these 2 cases had neoplastic change in 3 sites. The rate of neoplastic change was 50% concomitant adenoma. In the whole group, of the 18 cancer sites, 8 nidi were less than 3cm. CONCLUSION Synchronous cancer of large intestines is not rare, and is related to malignant change of adenomas. complete colonoscopy is an important means to improve diagnostic rate.