title: Involvement of NF-κB and Bcl2/Bax signaling pathways in the apoptosis of MCF7 cells induced by a xanthone compound Pyranocycloartobiloxanthone A.
abstract: The plant Artocarpus obtusus is a tropical plant that belongs to the family Moraceae. In the present study a xanthone compound Pyranocycloartobiloxanthone A (PA) was isolated from this plant and the apoptosis mechanism was investigated. PA induced cytotoxicity was observed using MTT assay. High content screening (HCS) was used to observe the nuclear condensation, cell permeability, mitochondrial membrane potential (MMP) and cytochrome c release. Reactive oxygen species formation was investigated on treated cells by using fluorescent analysis. Human apoptosis proteome profiler assays were performed to investigate the mechanism of cell death. In addition mRNA levels of Bax and Bcl2 were also checked using RT-PCR. Caspase 3/7, 8 and 9 were measured for their induction while treatment. The involvement of NF-κB was analyzed using HCS assay. The results showed that PA possesses the characteristics of selectively inducing cell death of tumor cells as no inhibition was observed in non-tumorigenic cells even at 30 μg/ml. Treatment of MCF7 cells with PA induced apoptosis with cell death-transducing signals, that regulate the MMP by down-regulation of Bcl2 and up-regulation of Bax, triggering the cytochrome c release from mitochondria to cytosol. The release of cytochrome c triggered the activation of caspases-9, then activates downstream executioner caspase-3/7 and consequently cleaved specific substrates leading to apoptotic changes. This form of apoptosis was found closely associated with the extrinsic pathway caspase (caspase-8) and inhibition of translocation of NF-κB from cytoplasm to nucleus. The results demonstrated that PA induced apoptosis of MCF7 cells through NF-κB and Bcl2/Bax signaling pathways with the involvement of caspases.
authors: Department of Pharmacy, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors: Syam
authors: S
authors: Mohan
authors: Siddig Ibrahim
authors: SI
authors: Abdelwahab
authors: Behnam
authors: B
authors: Kamalidehghan
authors: Suvitha
authors: S
authors: Syam
authors: Koh Sue
authors: KS
authors: May
authors: Nabil Saad Mohammed
authors: NS
authors: Harmal
authors: Noor
authors: N
authors: Shafifiyaz
authors: A Hamid A
authors: AH
authors: Hadi
authors: Najihah Mohd
authors: NM
authors: Hashim
authors: Mawardi
authors: M
authors: Rahmani
authors: Manal Mohamed Elhassan
authors: MM
authors: Taha
authors: Shiau-Chuen
authors: SC
authors: Cheah
authors: Asdren
authors: A
authors: Zajmi
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D031622:Artocarpus / Q000737:chemistry*; D020169:Caspases / Q000378:metabolism; D016923:Cell Death; D002463:Cell Membrane Permeability; D045304:Cytochromes c / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics; D006801:Humans; D061986:MCF-7 Cells; D053078:Membrane Potential, Mitochondrial; D008928:Mitochondria / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism*; D040081:Protein Array Analysis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D015854:Up-Regulation / Q000235:genetics; D044004:Xanthones / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D051028:bcl-2-Associated X Protein / Q000235:genetics
chemical_list: D016328:NF-kappa B; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D044004:Xanthones; D051028:bcl-2-Associated X Protein; C549169:pyranocycloartobiloxanthone A; D045304:Cytochromes c; D020169:Caspases