Dentatin isolated from Clausena excavata induces apoptosis in MCF-7 cells through the intrinsic pathway with involvement of NF-¦ÊB signalling and G0/G1 cell cycle arrest: A bioassay-guided approach

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• 作者：Ismail Adam Arbab^a ; Ahmad Bustamam Abdul^a ; ^{ahmadbstmm@yahoo.com} ; Mohd Aspollah Sukari^b ; Rasedee Abdullah^c ; Suvitha Syam^a ; ^d ; Behnam Kamalidehghan^d ; Mohamed Yousif Ibrahim^d ; Manal Mohamed Elhassan Taha^e ; Siddig Ibrahim Abdelwahab^e ; Hapipah Mohd Ali^f ; Syam Mohan^d ; ^{syammohanm@yahoo.com}
• 关键词：DTN ; Dentatin ; MMP ; Mitochondrial membrane potential ; NF-¦ÊB ; Nuclear factor-kappa B ; TNF-¦Á ; Tumour necrosis factor alpha ; ROS ; Reactive oxygen species ; DCFH-DA ; 2&prime ; 7&prime ; -dichlorofluorescein diacetate ; MPTP ; Mitochondrial membrane transition por
• 刊名：Journal of Ethnopharmacology
• 出版年：2013
• 出版时间：9 January, 2013
• 年：2013
• 卷：145
• 期：1
• 页码：343-354
• 全文大小：2604 K

文摘

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-¦ÊB) 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 (p<0.05) and ROS was significantly elevated. Moreover, DTN significantly blocked the induced translocation of NF-¦ÊB 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-¦ÊB signalling pathway.