Dissection of mechanistic action of anticancer multidrug resistance reversal agents from a natural product library.

• Main Author: Ong, Yi Jun.
• Other Authors: Zhao Yan
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Science::Biological sciences::Microbiology::Drug Resistance
• Online Access: http://hdl.handle.net/10356/39580
• Institution: Nanyang Technological University

The phenomenon of multidrug resistant (MDR) ovarian cancer is a major obstacle to successful cancer treatment. Thapsigargin, a natural sesquiterpene lactone, has been studied for its MDR reversal effects against MDR cancers by inducing endoplasmic recticulum stress and cell death. In this study, we aimed to investigate the underlying mechanisms of Thapsigargin in potentiating cytotoxicity on ovarian cancer cells (A2780) and its Doxorubicin resistant strain (A2780/ADR). MTT assays showed combination treatment with Thapsigargin and Doxorubicin exhibited higher cytotoxicity compared to Thapsigargin or Doxorubicin alone. Concurrently, fluorescence-activated cell sorting analysis displayed a significant increase in dead cells via mitochondrial apoptotic pathway. Further analysis with Western blot demonstrated the induction of apoptotic markers: cleaved caspase 3, cleaved caspase 9 and cleaved PARP. Pre-treatment with general caspase inhibitor, Q-VD-Oph, led to decreased expression of these proteins. Together, these results implied that combination treatment with Thapsigargin and Doxorubicin induced a higher cell death via caspase-dependent apoptosis pathway. Elucidation of the mechanisms of cell death caused by Thapsigargin and Doxorubicin may lead to the development of effective treatment for MDR ovarian cancer.