Expression of the miR-190 family is increased under DDT exposure in vivo and in vitro.

A non-genotoxic insecticide dichlorodiphenyltrichloroethane (DDT), can affect mRNA and microRNA levels, however, its precise mechanism of action remains poorly understood. Using in silico methods we found that the rat miR-190 family is potentially regulated by CAR and ER receptors activated by DDT. We showed that exposure to DDT results in a dose- and organ-dependent increase in the expression of miR-190a, -190b in the liver, uterus, ovaries and mammary gland of female Wistar rats. Additionally, we demonstrate a decrease in protein product level of Tp53inp1, the target gene of these microRNAs, in the rat uterus. It is known that miR-190 is probably regulated by ER in humans, thus we measured the level of miR-190a, -190b in primary cultures of malignant and normal human endometrial cells treated with different doses of DDT. We detected an increase in miR-190b level in normal endometrial cells under DDT exposure. Thus, our results indicate that DDT exposure lead to change in the expression of oncogenic miR-190 family and its target gene Tp53inp1 which may be due to activation of CAR and ER.