Induction of actin disruption and downregulation of P-glycoprotein expression by solamargine in multidrug-resistant K562/A02 cells

• Published in: Chinese medical journal Vol. 124; no. 13; pp. 2038 - 2044
• Main Authors: Li, Xia, Zhao, Ying, Ji, Mei, Liu, Shan-Shan, Cui, Min, Lou, Hong-Xiang
• Format: Journal Article
• Language: English
• Published: China School of Ocean, Shandong University, Weihai, Shandong 264209,China%School of Pharmaceutical Sciences, Shandong University, Jinan, Shandong 250012, China%School of Ocean, Shandong University, Weihai, Shandong 264209,China 05.07.2011; School of Pharmaceutical Sciences, Shandong University, Jinan, Shandong 250012, China
• Subjects: Actins - metabolism; ATP-Binding Cassette, Sub-Family B, Member 1 - metabolism; Cell Line, Tumor; Drug Resistance, Multiple - drug effects; Drug Resistance, Neoplasm - drug effects; Gene Expression Regulation, Neoplastic - drug effects; Humans; K562 Cells; mRNA表达; Solanaceous Alkaloids - pharmacology; Western印迹法; 免疫荧光染色; 多药耐药; 糖蛋白; 细胞凋亡; 肌动蛋白; 诱导; P-glycoprotein; apoptosis; solamargine; multidrug-resistant
• ISSN: 0366-6999; 2542-5641
• DOI: 10.3760/cma.j.issn.0366-6999.2011.13.021

Background Solamargine （SM）, a steroidal glycoalkaloid isolated from the Chinese herb Solanum incanum, has been shown to inhibit the growth of some cancer cell lines and induce significant apoptosis. However, the effects of SM on multidrug-resistant （MDR） cells and the molecular mechanisms involved are poorly understood. The purpose of this study was to evaluate the anti-MDR effects of SM and the associated mechanisms in MDR K562/A02 cells. Methods The cytotoxicity of SM was measured by 3-（4,5-dimethylthiazol）-2,5-diphenyltetrazolium bromide （MTT） assay. The 14＇,6-diamidino-2-phenylindole （DAPi） nuclear staining and flow cytometry were used to detect SM-induced apoptosis. The mRNA expression of P-glycoprotein （P-gp） was investigated by real-time PCR （RT-PCR）. Western blotting was used to determine the expression of Bcl-2, Bax, and actin. The changes in the morphology of actin were examined with immunofluorescence staining. Results MTT results showed that SM effectively killed the MDR sublines K562/A02, KB/VCR, and H460/paclitaxel （Taxol）, and their parental cell lines K562, KB, and H460 to an equivalent or more sensitive degree. Based on the results by flow cytometry and immunostaining, the pro-apoptotic effects of SM were observed in MDR K562/A02 cells. Furthermore, the RT-PCR results showed that SM induced the downregulation of MDR1 mRNA. In addition, the expression of P-gp and actin was decreased in the SM-treated cells, as measured by western blotting and immunostaining. Conclusions These results demonstrate that SM effectively triggers apoptosis in MDR tumor cells, which is associated with actin disruption and downregulation of MDR1 expression. This compound may merit further investigation as a Potential therapeutic aaent that bvDasses the MDR mechanism for the treatment of MDR tumors.