Antiproliferative effects of cucurbitacin B in breast cancer cells: Down-regulation of the c-Myc/hTERT/telomerase pathway and obstruction of the cell cycle

• Main Authors: Duangmano,S., Dakeng,S., Jiratchariyakul,W., Suksamrarn,A., Smith,D.R., Patmasiriwat,P.
• Format: Article
• Published: Multidisciplinary Digital Publishing Institute (MDPI) 2015
• Subjects: Catalysis; Computer Science Applications; Spectroscopy; Organic Chemistry; Molecular Biology; Physical and Theoretical Chemistry; Inorganic Chemistry
• Online Access: http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=78650985401&origin=inward; http://cmuir.cmu.ac.th/handle/6653943832/38090
• Institution: Chiang Mai University

Naturally occurring cucurbitacins have been shown to have anticancer, antimicrobial and anti-inflammatory activities. In this study, we determined the effects of cucurbitacin B extracted from the Thai herb Trichosanthes cucumerina L. on telomerase regulation in three human breast cancer cell lines (T47D, SKBR-3, and MCF-7) and a mammary epithelium cell line (HBL-100). Cell viability after treatment with cucurbitacin B, which is an active ingredient of this herb, was assessed. Telomeric Repeat Amplification Protocol (TRAP) assays and RT-PCR (qualitative and realtime) were performed to investigate activity of telomerase as well as expression of human telomerase reverse transcriptase (hTERT) and c-Myc. The c-Myc protein level was also determined in SKBR-3 and HBL-100 cells. Our results show that the cucurbitacin B inhibits growth and telomerase activity in the three breast cancer cell lines and exerts an obvious inhibitory effect in the estrogen receptor (ER)-negative breast cancer SKBR-3 cells. The expression of hTERT and c-Myc were also inhibited by cucurbitacin B, In addition, a clear reduction of c-Myc protein was observed after treatment in SKBR-3 cells even with a concentration of cucurbitacin B that was ten-times lower compared to the concentration used for HBL-100. Our findings imply that cucurbitacin B exerts an anticancer effect by inhibiting telomerase via down regulating both the hTERT and c-Myc expression in breast cancer cells. © 2010 by the authors.