Paris polyphylla extract inhibits proliferation and promotes apoptosis in A549 lung cancer cells

Ruolan Hu,Ya Yang,Xiaogang Hu,Wei Yu,Yan Zhuo

doi:10.4314/tjpr.v16i9.11

Abstract

Purpose: To investigate the effect of Paris polyphylla extract (PPE) on proliferation and apoptosis in A549 human lung cancer cells. Methods: Morphological changes were examined by microscopy in A549 cells after exposure to PPE. Trypan blue staining of living cells was used to aid the construction of the cell growth curve after treatment with different concentrations of PPE. The influence of PPE on cell proliferation, apoptosis and cell cycle were determined by MTT assay. Protein expressions of key apoptosis-related enzymes were determined by immuno-cytochemical method. Results: PPE inhibited the growth of A549 lung cancer cells at a concentration range of 12.5 – 200.0 μg/mL. Flow cytometry revealed that PPE promoted apoptosis in A549 cells. The proportion of cells in G0/G1-phase increased significantly ( p < 0.01), while the proportion of cells in S- and G2/M-phases decreased correspondingly, indicating that the cells were in G0/G1-phase arrest. Cell cycle arrest and apoptosis-inducing effect gradually increased with increase in PPE concentration. With increasing concentration of PPE, there was significant increase in the expressions of caspase-8, caspase-3 and caspase-9, but significant decrease in Ki-67, p21ras protein ( p < 0.01). Conclusion: PPE exerts pronounced inhibitory activity on the proliferation of A549 lung cancer cells. It also induces apoptosis in A549 cells, most probably by a mechanism related to Ki-67 and p21 ras protein expression, and arrest of cell cycle in G0/G1-phase. Keywords: Paris polyphylla, Antitumor activity, Lung cancer, A549 cells, p21 ras protein expression, Caspase, Cell cycle arrest, Apoptosis

Highlights

The morbidity and mortality of lung cancer account for 13 and 19.4 %, respectively, worldwide [1]
Lung cancer is divided into small cell lung carcinoma (SCLC) and non-small cell lung carcinoma (NSCLC)
Earlystage NSCLC is treated by surgical intervention, while mid-late NSCLC is treated with radiotherapy and chemotherapy

Summary

INTRODUCTION

The morbidity and mortality of lung cancer account for 13 and 19.4 %, respectively, worldwide [1]. A suspension of A549 cells at the logarithmic growth phase in RPMI 1640 medium was adjusted to a density of 1.0 x 105 cells/mL in a 48-well culture plate, and cultured for 24 h at 37 °C to achieve adherence. A suspension of the A549 cells (0.2 mL) at logarithmic phase was seeded in a 96-well plate with each well containing 5×103 cells, and cultured overnight for cell adhesion. A suspension of 549 human lung cancer cells (5.0 × 104 cells/mL) at logarithmic growth phase was seeded in 24-well plates (100 μL in each well), and cultured in RPMI 1640 medium for 24 h for adherence. The culture medium was removed, and 3mL of PPE was added to different cells to final concentrations of 20, 40, 80 and 160 μg/mL.

RESULTS

DISCUSSION

Conflict of Interest