Pancratistatin Inhibits the Growth of Colorectal Cancer Cells by Inducing Apoptosis, Autophagy, and G2/M Cell Cycle Arrest
MEDICAL SCIENCE MONITOR
Authors: Xiong, Yong; Xiong, Yi-Jia; Liu, Dong-Yang; Shen, Rong-Rong
Abstract
Background: Worldwide, colorectal cancer is ranked as the third most prevalent cancer. The natural compound, pancratistatin, extracted from the spider lily, has previously been shown to target apoptosis in cancer cells lines. This study aimed to investigate the effects of pancratistatin in human colorectal cancer cells in vitro. Material/Methods: Human colorectal cancer cell lines, including HTC-15 cells, were compared with a normal human colonic fibro- blast cell line, CDD-18Co. Cells were treated with increasing doses of pancratistatin. The MTT assay was used to assess cell viability. Fluorescence microscopy using DAPI and Annexin-V/propidium iodide (PI) was used to detect cell apoptosis. Cell autophagy was detected by electron microscopy. Cell migration was evaluated using a wound healing assay, and Western blot determined the expression levels of cell cycle proteins. Results: Pancratistatin inhibited the growth of the colorectal cancer cells with an IC50 ranging from 15-25 mu M, but had a limited effect in normal CCD-18Co cells, with an IC50 of >100 mu M. Pancratistatin reduced HCT-15 cell migration. Growth inhibition due to pancratistatin was associated with morphological changes of HCT-15 cells and included autophagy and apoptosis, and increased expression the autophagic proteins, LC3II, beclin-1, and Bax. Pancratistatin induced arrest of HCT-15 cells at G2/M of the cell cycle and inhibited phosphorylation of cdc2/cyclin-dependent kinase 1 (CDK1) and Cdc25c and the expression of cyclin B1. Conclusions: Pancratistatin inhibited the growth of colorectal cancer cells in vitro by inducing apoptosis, autophagy, and G2/M cell cycle arrest.
Cyclin-dependent kinase 1 disruption inhibits angiogenesis by inducing cell cycle arrest and apoptosis
EXPERIMENTAL AND THERAPEUTIC MEDICINE
Authors: Gao, Xin; Zhang, Yuan; Zhang, Rui; Zhao, Zichan; Zhang, Haorui; Wu, Jinhui; Shen, Wei; Zhong, Ming
Abstract
Angiogenesis is a complex process, which involves the sprouting of new blood vessels from pre-existing vasculature. Pathological retinal angiogenesis can lead to vision loss and even blindness. Cyclin-dependent kinase 1 (CDK1) is involved in regulation of the cell cycle and is reported to contribute to tumor progression. However, the role of CDK1 in retinal angiogenesis is largely unknown. The purpose of the present study was to investigate the role of CDK1 in retinal angiogenesis. Western blotting, reverse transcription-quantitative PCR (RT-qPCR) analysis, immunofluorescence and immunohistochemistry were used to evaluate the expression of CDK1 in pathological angiogenesis using an oxygen-induced retinopathy (OIR) mouse model. Small interfering (si)RNA sequences against CDK1 were synthesized and incubated with retinal cells. The efficiency of knockdown was confirmed by western blot and RT-qPCR assays. The effect of CDK1 siRNAs on angiogenesis in vitro was investigated using EdU cell proliferation, cell migration and tube formation assays. Subsequently, flow cytometry was used to assess the effects of CDK1 siRNAs on cell cycle distribution and on the induction of apoptosis. The expression levels of cell cycle- and apoptosis-related genes were detected using western blotting. CDK1 was overexpressed in pathological retinal angiogenesis. CDK1 siRNAs inhibited human umbilical vein endothelial cell proliferation, migration and tube formation. The possible mechanisms involved the induction of cell cycle arrest at the G2/M phase and the induction of apoptosis via an increase in the expression levels of p21 and p53. In conclusion, the data indicated that CDK1 was overexpressed in the OIR model and that silencing of CDK1 inhibited angiogenesis in vitro. CDK1 may be a novel therapeutic target for pathological retinal angiogenesis.