BACKGROUND: As a traditional Chinese medicine herb, Chonglou (Paris polyphylla var. chensiins) has been used as anticancer medicine in China in recent decades, as it can induce cell cycle arrest and apoptosis in numerous cancer cells. The saponins extract from the rhizoma of Chonglou [Rhizoma Paridis saponins (RPS)] is known as the main active component for anticancer treatment. However, the molecular mechanism of the anticancer effect of RPS is unknown.

MATERIAL AND METHODS: The present study evaluated the effect of RPS in non-small-cell lung cancer (NSCLC) A549 cells using the 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyl tetrazolium bromide (MTT) assay and flow cytometry. Subsequently, the expression of several genes associated with cell cycle and apoptosis were detected by reverse transcription-quantitative polymerase chain reaction (qRT-PCR) and Western blotting.

RESULTS: RPS was revealed to inhibit cell growth, causing a number of cells to accumulate in the G 1 phase of the cell cycle, leading to apoptosis. In addition, the effect was dose-dependent. Moreover, the results of qRT-PCR and Western blotting showed that p53 and cyclin-dependent kinase 2 (CDK2) were significantly downregulated, and that BCL2, BAX, and p21 were upregulated, by RPS treatment.

CONCLUSIONS: We speculated that the RPS could act on a pathway, including p53, p21, BCL2, BAX, and CDK2, and results in G1 cell cycle arrest and apoptosis in NSCLC cells.

Keywords: Antineoplastic Agents, Phytogenic - pharmacology, Angiosperms - chemistry, Apoptosis - genetics, Carcinoma, Non-Small-Cell Lung - pathology, Cyclin-Dependent Kinase 2 - genetics, Cyclin-Dependent Kinase Inhibitor p21 - genetics, G1 Phase Cell Cycle Checkpoints - genetics, Gene Expression - drug effects, Genes, bcl-2 - drug effects, Genes, p53 - drug effects, Lung Neoplasms - pathology, Plants, Medicinal - chemistry, Saponins - pharmacology, bcl-2-Associated X Protein - genetics