Dentatin isolated from Clausena excavata induces apoptosis in MCF-7 cellsthrough the intrinsic pathway with involvement of NF-kB signalling andG0/G1 cell cycle arrest : a bioassay-guided approach
Ethnopharmacological relevance: Clausena excavata Burm. f. has been used in folk medicines in eastern Thailand for the treatment of cancer. Materials and methods: To investigate the apoptosis mechanism, we isolated dentatin (DTN) from this plant using a bioassay-guided approach. DTN-induced cytot...
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Main Authors: | , , , , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Elsevier
2013
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Online Access: | http://psasir.upm.edu.my/id/eprint/30034/1/Dentatin%20isolated%20from%20Clausena%20excavata%20induces%20apoptosis%20in%20MCF.pdf http://psasir.upm.edu.my/id/eprint/30034/ http://dx.doi.org/10.1016/j.jep.2012.11.020 |
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Institution: | Universiti Putra Malaysia |
Language: | English |
Summary: | Ethnopharmacological relevance: Clausena excavata Burm. f. has been used in folk medicines in eastern
Thailand for the treatment of cancer.
Materials and methods: To investigate the apoptosis mechanism, we isolated dentatin (DTN) from this plant
using a bioassay-guided approach. DTN-induced cytotoxicity was observed with the MTT assay. Acridine
orange/propidium iodide staining was used to detect cells in early apoptosis and high content screening
(HCS) to observe nuclear condensation, cell permeability, mitochondrial membrane potential (MMP) and
cytochrome c release. Apoptosis was confirmed with a clonogenic assay, DNA laddering and caspase 3/7
and 9 assays. Reactive oxygen species (ROS) formation, Bcl-2 and Bax expression, and cell cycle arrest were
also investigated. The involvement of nuclear factor-kappa B (NF-kB) was analysed with the HCS assay.
Results: A significant increase in chromatin condensation in the cell nucleus was observed by fluorescence
analysis. Apoptosis was confirmed by the reduced number of colonies in the clonogenic assay and the
increased number of cellular DNA breaks in treated cells observed as a DNA ladder. Treatment of MCF-7 cells
with DTN encouraged apoptosis with cell death-transducing signals that reduced MMP by down-regulation
of Bcl-2 and up-regulation of Bax, triggering cytochrome c release from the mitochondria to the cytosol.
The released cytochrome c triggered the activation of caspase 9 followed by the executioner caspase 3/7.
DTN treatment significantly arrested MCF-7 cells at the G0/G1 phase (po0.05) and ROS was significantly
elevated. Moreover, DTN significantly blocked the induced translocation of NF-kB from cytoplasm to nucleus.
Conclusion: Together, the results demonstrated that the DTN isolated from Clausena excavata inhibited the
proliferation of MCF-7 cells, leading to cell cycle arrest and programmed cell death, which was confirmed to
occur through the mitochondrial pathway with involvement of the NF-kB signalling pathway. |
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