The oceans are considered as magnificent source of bioactive metabolites, of which marine sponges associated organisms are being the most effective producers of various bioactive molecules. We previously reported that cyclo(-Pro-Tyr) (CPT), a dipeptide from marine sponge Callyspongia fistularis associated Bacillus pumilus AMK1 bacteria for its anti-proliferative activity through down regulating PI3K signaling and inducing mitochondrial mediated apoptosis in HepG2 cells. Further we emphasize to study the role of CPT against hepatocellular carcinoma (HCC) induced by N-diethylnitrosamine (DEN) in male swiss albino mice in vivo. In this study, HCC was induced by the administration of DEN (75 mg/kg b.wt) dissolved in saline once/week for 3 weeks, then 100 mg/kg b.wt for another successive 3 weeks and observed for 18 weeks. CPT (100 mg/kg b.wt) treatment was started after 14 weeks of DEN induction. The obtained results demonstrated that CPT altered DEN induced oxidative stress by decreasing serum SGOT and SGPT followed increment in the antioxidants such as superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. This was accompanied by decreased accumulation of glycoconjugates and argyophilic nucleolar organizing regions in the treatment groups. Further, CPT significantly reduced the levels of phospho-PI3Kinase p85 and phospho-AKT and upregulation of PTEN compared with DEN induced group. Besides this, decreased expression of Bcl-2 and increased expression of Bax, Caspase 3, and p53 was observed in CPT treated mice. Therefore, the anticancer mechanism of CPT against DEN induced HCC may be associated with the regulation of the PI3K/AKT signaling pathway, which ultimately stimulates apoptosis.
Keywords: N-diethylnitrosamine; PI3K/AKT pathway; antioxidants; cyclo(-Pro-Tyr); glycoconjugates; hepatocellular carcinoma.
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