Anticancer activity of cepharanthine on non-small cell lung cancer cells

Abstract

Cepharanthine (CEP) is a biscoclaurine alkaloid, isolated from the roots of Stephania cepharanthine Hayata that possesses potent anticancer properties against several types of cancer such as hepatocellular carcinoma, colorectal cancer, leukemia and ovarian cancer. However, there is still limited information regarding to its effects on non-small cell lung cancer cells. Therefore, the objectives of the present study were to determine the cytotoxicity of CEP and its underlying mechanisms in non-small cell lung cancer cells expressing wild-type p53 and EGFR (A549) and non-small cell lung cancer cells expressing mutant p53 and EGFR (H1975). The results indicated that CEP significantly inhibited the viability of A549 and H1975 cells in a concentration-dependent manner, with the inhibitory concentration at 50% cell growth (IC50) values of 4.31±0.52 and 11.81±2.07 µM, respectively. Moreover, apoptosis-inducing effect of CEP were detected in both A549 and H1975 cells. Western blot results demonstrated that CEP could upregulate Bax and Bak as well as downregulate of Bcl-2 and Bcl-XL in A549 cells and downregulate Bcl-2 in H1975 cells. Also, CEP was able to induce the cleavage of poly-(ADP-ribose) poly­merase (PARP) in both A549 and H1975 cells. It should be noted that apoptosis-inducing effect of CEP were diminished when the cells were pretreated with N-acetylcysteine (NAC), a ROS scavenger, suggesting that CEP-induced apoptosis was mediated through ROS generation. In addition, CEP inhibited ERK signaling pathway in A549 cells but activated ERK signaling pathway in H1975 cells. Moreover, CEP could inhibit STAT3 and Akt signaling pathways in both NSCLC cell lines. Remarkably, NAC could prevent CEP-mediated inhibition of STAT3 in both A549 and H1975 cells and CEP-mediated Akt inhibition in H1975 cells, indicating that ROS is involved in the inhibitory effects of CEP on STAT3 and Akt signaling pathways. Taken together, these results suggest that CEP exhibited potent cytotoxicity through induction of apoptosis, generation of ROS and modulation of STAT3, PI3K/Akt and MAPK/ERK signaling pathways in NSCLC cells. Our findings demonstrated that CEP may have a potential to be develop as a novel anticancer drug for lung cancer.