MitoQ demonstrates connexin- and p53-mediated cancer chemoprevention in N-nitrosodiethylamine-induced hepatocarcinogenesis rodent model

Cancer chemoprevention is an approach that offers huge potential for preventing/retarding carcinogenesis. MitoQ is well-known and extensively studied mitochondria-targeted antioxidants for its applications in diseases linked with oxidative stress. In the present study chemopreventive potential of mitoQ was studied with a focus on the role of gap-junctions and p53 at an advanced stage of HCC. BALB/c mice model of hepatocarcinogenesis was established using N-nitrosodiethylamine as a carcinogen (200 mg/kg b. w., cumulative dose, intraperitoneally). The chemopreventive effect of mitoQ was studied by pre-protecting animals with mitoQ (0.125 mg/kg b. w., orally once a week) till the termination of the study. The tumors developed in the course of the study were histopathologically analyzed and statistically evaluated. The mechanistic role of mitoQ was investigated in terms of mitochondrial oxidative stress, expression of 8-OHdG, Cx26, Cx32, p53 and status of gap-junctional intercellular communication (GJIC) in tumors. Chemopreventive activity of mitoQ was evident from improved survival of animals, significantly (p ≤ 0.05) lower tumor multiplicity, tumor incidence and a total number of tumors. MitoQ treatment significantly (p ≤ 0.05) decreased mitochondrial oxidative stress as indicated by reduced mtROS and mtLPO. Increased staining intensity of 8-OHdG and internalization of Cx26, Cx32 which was observed in hepatic tumors was reduced upon mitoQ treatment. Furthermore, the expression of Cx26, Cx32 and p53 was significantly increased along with improvement in GJIC in mitoQ treatment group. MitoQ demonstrated its chemopreventive potential probably by regulating mtROS, connexins and p53 in hepatocarcinogenesis.