Pterostilbene (3',5'-dimethoxy-resveratrol) exerts potent antitumor effects in HeLa human cervical cancer cells via disruption of mitochondrial membrane potential, apoptosis induction and targeting m-TOR/PI3K/Akt signalling pathway.

PURPOSE

To examine the molecular mechanism of action behind the anticancer effects of pterostilbene in HeLa human cervical cancer cells.

METHODS

MTS assay was used to study the pterostilbene cytotoxic effects, while inverted phase contrast and fluorescence microscopy was used to study the effects of the drug on the cell apoptosis and changes in cell morphology. Flow cytometry was used to study changes in mitochondrial membrane potential (MMP), while immunoblotting assay was used to demonstrate its effects on m-TOR/PI3K/Akt protein signalling pathway.

RESULTS

Pterostilbene induced potent, dose-dependent and time-dependent cytotoxic effects in HeLa cancer cells exhibiting IC50 of 101.2 µM and 65.9 µM at 24 and 48 hrs time intervals, respectively. As compared to the untreated control cells which revealed normal cell morphology, pterostilbene-treated cells exhibited significant cellular shrinkage which increased with increasing doses of the drug. Untreated control cells showed complete green fluorescence corresponding to absence of apoptosis. However, pterostilbene-treated cells with 25, 100 and 200 µM showed increasing emission of red/orange fluorescence corresponding to apoptotic induction. Pterostilbene-treated cells showed evident signs of DNA ladder formation and the effect increased with increasing concentrations of the drug. The percentage of cells with depolarized mitochondria (loss of MMP) increased from 2.3% in the control group to 24.5, 43.2 and 65.8% in cells treated with 0, 25, 100 and 200 µM concentration of pterostilbene, respectively.

CONCLUSION

Pterostilbene exerts potent anticancer effects in HeLa human cervical cancer cells via disruption of MMP, apoptosis induction and targeting m-TOR/PI3K/Akt signalling pathway.