The effect of Tubocapsanolide A on the colorectal cancer cell lines
The withanolid compounds (Tubocapsanolide A, B, and C) were purify from Tubocapsium anomalum and shown with cell growth inhibitory property. However, the molecular mechanisms of withanolide type compounds on the cell have not been fully clarified. Tubocapsanolide A, B, and C (TA, TB, and TC) of antiproliferative activity on human colorectal adenocarcinoma cells, HT29 and HCT116, were tested and the inhibitory concentration of 50% cell viability (IC50) for these compounds was determined by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. We found that TA has the best inhibitory effect in these compounds. Therefore we utilized TA to study the mechanism of cell toxicity. The caspase 3 and PARP cleavage experiment results indicated that TA induced apoptosis was time and dose dependent. Cells with functional p53 (HCT116) are more sensitive to TA compared to the mutant p53 cells (HT29). With low dose TA treatment, HCT116 and HT29 are arrested at G1 and G2/M phase respectively. We also found that TA induced sub-G1 accumulation and reactive oxygen species (ROS) release with flow cytometry analysis. Pretreatment of N-Acetyl-L-cysteine (NAC), an antioxidant agent, can reverse the antiproliferation effect by TA. Our results indicated that TA can induce cell apoptosis and intracellular ROS generation. The ROS triggers cells damage and decreases the mitochondria membrane potential and thus induce cell apoptosis.
Advisor:Yow-ling Shiue; Hurng-wern Huang; Chao-neng Tseng
School:National Sun Yat-Sen University
School Location:China - Taiwan
Source Type:Master's Thesis
Keywords:tubocapsanolide a withanolide compound
Date of Publication:08/24/2007