Effect of petroleum ether extract from Holotrichia diomphalia grub on proliferation and apoptosis of human cervical carcinoma HeLa cells

Objective To investigate the effect of petroleum ether extract from the grub of Holotrichia diomphalia on proliferation and apoptosis of human cervical carcinoma HeLa cells in vitro and explore its probable molecular mechanisms. Methods The growth inhibition of petroleum ether extract from the grub of H. diomphalia on HeLa cells was measured with MTT assay. Apoptosis cells were determined by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method. The Bcl-2, Bax, caspase-8, and caspase-3 protein expressions were determined by immunohistochemical S-P staining technique. Results Petroleum ether extract from the grub of H. diomphalia significantly inhibited the proliferation of HeLa cells in a dose-and time-dependent manner (P0.01). The effect of petroleum ether extract from the grub of H. diomphalia increased HeLa apoptosis numbers greatly with the time lasting. The apoptosis of HeLa could be induced by the grub extract in a dose-and time-dependent manner. After treated with the extract, the Bcl-2 expression was decreased, while the Bax, caspase-8, and caspase-3 expressions were increased; the expressions of the four kinds of protein were significantly changed among the different treatings with the grub extract (P0.01). Conclusion Petroleum ether extract from the grub of H. diomphalia could significantly inhibit the proliferation and induce the apoptosis of HeLa cell in vitro. Before treating 48 h on HeLa cells with the grub extract (50 μg/mL), the inhibitory effect on proliferation and its cytotoxicity was mainly completed by the induction of apoptosis. The mechanism of the grub petroleum ether extract inducing apoptosis for HeLa might be related to down-regulation of Bcl-2 expression and up-regulation of Bax, caspase-8, and caspase-3 expressions.