[Xihuang Pills and its main components inhibit PI3K/Akt/mTOR signaling pathways and promote the apoptosis of prostate cancer cells in PC-3 tumor-bearing mice]

Objective: To evaluate the effects of Xihuang Pills (XHP) and its main components on PI3K, AKT and mTOR signaling pathways and cell apoptosis of castration-resistant human PCa PC-3 cell subcutaneously transplanted tumors in nude mice.

Methods: We assigned 36 PC-3 tumor-bearing model mice to six groups of equal numbers to be treated with XHP, musk, calculus bovis (CB), musk + CB and docetaxel, respectively. After 14 days of intervention, we calculated the tumor-inhibition rate in different groups, observed the morphology of the tumor cells by HE staining, determined the levels of PI3K, Akt and mTOR mRNA by RT-qPCR, and determined the expressions of PI3K, Akt and mTOR signaling pathways and caspase-3 and caspase-9 proteins by Western blot.

Results: After 14 days of medication, the tumor-inhibition rates in the XHP, musk, CB, musk + CB and docetaxel groups were 29.67%, 5.52%, 7.26%, 12.88% and 6.26%, respectively. HE staining showed the formation of apoptotic bodies in the tumor tissues after intervention, especially in the XHP and musk + CB groups. The mRNA and phosphorylated protein expressions of PI3K, Akt and mTOR were significantly down-regulated (P < 0.01), and so were the expressions of caspase-3 and caspase-9 proteins in the XHP and musk + CB groups in comparison with the control (P < 0.01).

Conclusions: Xihuang Pills, musk and calculus bovis can inhibit the growth of castration-resistant human PCa PC-3 cell subcutaneously transplanted tumors, which is associated with their effects of suppressing the abnormally activated PI3K, Akt and mTOR signaling pathways and promoting the apoptosis of PCa PC3 cells.