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Induction of apoptosis and the signalling pathways involved by dillenia suffruticosa dichloromethane root extract in mcf-7 and mda-mb-231 breast cancer cells


Citation

Foo, Jhi Biau (2015) Induction of apoptosis and the signalling pathways involved by dillenia suffruticosa dichloromethane root extract in mcf-7 and mda-mb-231 breast cancer cells. Doctoral thesis, Universiti Putra Malaysia.

Abstract

Dillenia suffruticosa has been used traditionally to treat cancerous growth. Previous study reported that dichloromethane extract of D. suffruticosa root (DCM-DS) was the most cytotoxic towards breast cancer cells. The present study investigated the mode of cell death and the signalling pathways involved in MCF-7 and MDA-MB-231 breast cancer cells treated with DCM-DS. DCM-DS was obtained by sequential solvent extraction. The cytotoxicity of DCM-DS was determined by using MTT assay. The mode of cell death was evaluated by using an inverted light microscope and AnnexinV/PI-flow cytometry analysis. Cell cycle analysis and measurement of intracellular reactive oxygen species (ROS) level were performed by using flow cytometry. The cells were co-treated with DCM-DS and antioxidants α-tocopherol or ascorbic acid to evaluate the involvement of ROS in the cytotoxicity of DCM-DS. Effect of DCM-DS on the expression of antioxidant, apoptotic, growth, survival genes and proteins were analysed by using GeXP-based multiplex system and Western blot, respectively. The compounds in DCM-DS were isolated by various chromatography techniques. The structure of the compounds was elucidated by using nuclear magnetic resonance analysis. DCM-DS was cytotoxic to the MCF-7 and MDA-MB-231 cells in a time-and dose-dependent manner. Cell cycle analysis revealed that DCM-DS induced G0/G1 and G2/M phase cell cycle arrest in MCF-7 and MDA-MB-231 cells, respectively. DCMDS induced apoptosis and oxidative stress in these two cell lines. Treatment with α- tocopherol reduced the cytotoxicity of DCM-DS at 50 µg/mL in the cells, suggesting that DCM-DS induced lipid peroxidation to destroy the cancer cells. Therefore, DCMDS can be employed as a pro-oxidant agent to treat breast cancer. The induction of apoptosis in MCF-7 and MDA-MB-231 cells by DCM-DS is possibly due to the activation of pro-apoptotic JNK1 and down-regulation of anti-apoptotic ERK1 and AKT1, which in turn down-regulates anti-apoptotic BCL-2 to increase the BAX/BCL-2 ratio to initiate the mitochondrial apoptotic pathway. The induction of cell cycle arrest in MCF-7 and MDA-MB-231 cells is possibly via p53/p21-dependent and p53- independent but p21-dependent pathway, respectively. A total of seven triterpene compounds were isolated. Betulinic acid (BA) appears to be the major and most cytotoxic compound in DCM-DS. Therefore, BA could be used as a mean for standardisation of herbal product from D. suffruticosa. In conclusion, the data suggest the potential application of DCM-DS in the treatment of breast cancer.


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Additional Metadata

Item Type: Thesis (Doctoral)
Call Number: IB 2015 19
Chairman Supervisor: Latifah Saiful Yazan, PhD
Divisions: Institute of Bioscience
Depositing User: Haridan Mohd Jais
Date Deposited: 22 May 2018 06:31
Last Modified: 22 May 2018 06:31
URI: http://psasir.upm.edu.my/id/eprint/64049
Statistic Details: View Download Statistic

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