Serum organochlorine pesticide levels in patients with colorectal cancer in Egypt

p,p′-Dichlorodiphenyltrichloroethane inhibits the apoptosis of colorectal adenocarcinoma DLD1 cells through PI3K/AKT and Hedgehog/Gli1 signaling pathways

p,p′-Dichlorodiphenyltrichloroethane is able to inhibit the apoptosis of human colorectal adenocarcinoma cells, which may be an important mechanism to contribute to colorectal cancer development.

p, p'-Dichlorodiphenyldichloroethylene induces colorectal adenocarcinoma cell proliferation through oxidative stress

p, p'-Dichlorodiphenyldichloroethylene (DDE), the major metabolite of Dichlorodiphenyltrichloroethane (DDT), is an organochlorine pollutant and associated with cancer progression. The present study investigated the possible effects of p,p'-DDE on colorectal cancer and the involved molecular mechanism. The results indicated that exposure to low concentrations of p,p'-DDE from 10(-10) to 10(-7) M for 96 h markedly enhanced proliferations of human colorectal adenocarcinoma cell lines. Moreover, p,p'-DDE exposure could activate Wnt/β-catenin and Hedgehog/Gli1 signaling cascades, and the expression level of c-Myc and cyclin D1 was significantly increased. Consistently, p,p'-DDE-induced cell proliferation along with upregulated c-Myc and cyclin D1 were impeded by β-catenin siRNA or Gli1 siRNA. In addition, p,p'-DDE was able to activate NADPH oxidase, generate reactive oxygen species (ROS) and reduce GSH content, superoxide dismutase (SOD) and calatase (CAT) activities. Treatment with antioxidants prevented p,p'-DDE-induced cell proliferation and signaling pathways of Wnt/β-catenin and Hedgehog/Gli1. These results indicated that p,p'-DDE promoted colorectal cancer cell proliferation through Wnt/β-catenin and Hedgehog/Gli1 signalings mediated by oxidative stress. The finding suggests an association between p,p'-DDE exposure and the risk of colorectal cancer progression.

Colorectal cancer and pollution

The incidence of colorectal carcinoma is increasing in young patients, in contrast to the well established wisdom that it is exclusively diagnosed in patients older than 40 years. In this survey, we examined all possible risk factors, and we recommend a number of measures for early detection in young patients who are at risk of developing this malignant tumor.