Inhibitory effect and mechanism of hirsuteine on NCI­H1299 lung cancer cell lines.

ABSTRACT

Traditionally, the bark of Uncaria rhynchophylla (UR) has been employed for the treatment of hypertension, cancer, convulsions, haemorrhage, autoimmune disorders and other ailments. The primary aim of the present study was to explore the antiproliferative activity of hirsuteine (HTE) isolated from UR over a range of concentrations in human NSCLC NCI-H1299 cells and to explore the mechanisms underlying its therapeutic efficacy. The effects of HTE on cell viability were examined using Cell Counting Kit-8 (CCK-8) and colony formation assays, while apoptosis was assessed by flow cytometry. Cell cycle progression was additionally evaluated via propidium iodide staining, while reverse transcription-quantitative PCR and western blotting methods were employed to assess the protein levels and genes related to apoptosis and progression of the cell cycle, respectively. NCI-H1299 cell proliferation was markedly suppressed by HTE in a time- and dose-dependent manner. However, clear changes in cell morphology were also induced, resulting in G0-G1 phase cell cycle arrest, which was associated with cyclin E and CDK2 downregulation. HTE additionally induced robust NSCLC NCI-H1299 cell apoptosis, downregulation of Bcl-2 and upregulation of cytoplasmic cytochrome C, Bax, Apaf1, cleaved caspase-3 and cleaved caspase-9, which together drove the observed apoptotic cell death. HTE could effectively suppress human NSCLC NCI-H1299 cell growth by inducing apoptotic death in a dose-dependent fashion in vitro, therefore elucidating the mechanism by which this phytomedicine acts as a potent anticancer compound that warrants study as a treatment for human NSCLC patients.