title: Silencing of JMJD2B induces cell apoptosis via mitochondria-mediated and death receptor-mediated pathway activation in colorectal cancer.
abstract: OBJECTIVE
  To investigate the molecular mechanism of colorectal cancer (CRC) cell apoptosis induced by the Jumonji domain containing 2B (JMJD2B) silencing.
  
  
  METHODS
  Both HCT116 and LoVo CRC cell lines were used for analyses. Cell apoptosis after JMJD2B silencing was determined by flow cytometry. JC-1 fluorescence probe was applied to measure the mitochondrial outer membrane permeabilization by flow cytometry and fluorescence microscopy. Immunofluorescence was used to detect cytochrome C translocation from mitochondria to cytosol after JMJD2B silencing. The efficacy of JMJD2B silencing on the protein levels of Bcl-2 family, caspase proteins, CCAAT/enhancer binding protein homologous protein (CHOP) and glucose-regulated protein 78 (GRP78) were detected by Western blot.
  
  
  RESULTS
  JMJD2B silencing induced CRC cell apoptosis via a decrease of the anti-apoptotic gene Bcl-2 family expression, leading to the translocation of Bak and Bax proteins and the promotion of mitochondrial membrane disruption, resulting in the release of cytochrome C from mitochondria and subsequent caspase-9 and caspase-3 cleavage. It also increased the amount of cleaved caspase-8 involved in the death receptor-related apoptotic pathway. Bcl-2 homology 3 interacting-domain death agonist (Bid), a specific caspase-8 substrate involved in the Fas signaling pathway, subsequently induced cleavage via caspase-8 activation. However, levels of CHOP and GRP78 remained unchanged after JMJD2B silencing.
  
  
  CONCLUSIONS
  JMJD2B silencing induced CRC cell apoptosis via both mitochondria-related and death receptor-related pathways. The cleavage of Bid activated by caspase-8 might serve as a crosstalk mediator between these two pathways in CRC.
authors: State Key Laboratory for Oncogenes and Related Genes, Key Laboratory of Gastroenterology & Hepatology, Ministry of Health, Division of Gastroenterology and Hepatology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Cancer Institute, Shanghai Institute of Digestive Disease, Shanghai, China.
authors: Bei Bei
authors: BB
authors: Sun
authors: Lin Na
authors: LN
authors: Fu
authors: Yun Qian
authors: YQ
authors: Wang
authors: Qin Yan
authors: QY
authors: Gao
authors: Jie
authors: J
authors: Xu
authors: Zhi Jun
authors: ZJ
authors: Cao
authors: Ying Xuan
authors: YX
authors: Chen
authors: Jing Yuan
authors: JY
authors: Fang
mesh_terms: D017209:Apoptosis / Q000235:genetics* / Q000502:physiology; D020169:Caspases / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D045304:Cytochromes c / Q000378:metabolism; D015536:Down-Regulation; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000502:physiology; D020868:Gene Silencing; D006801:Humans; D056484:Jumonji Domain-Containing Histone Demethylases / Q000235:genetics*; D008928:Mitochondria / Q000502:physiology*; D009363:Neoplasm Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D034622:RNA Interference; D053218:Receptors, Death Domain / Q000502:physiology; D014407:Tumor Cells, Cultured; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: C494772:BAK1 protein, human; C494826:BAX protein, human; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D053218:Receptors, Death Domain; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D045304:Cytochromes c; D056484:Jumonji Domain-Containing Histone Demethylases; C523637:KDM4B protein, human; D020169:Caspases
keywords: apoptosis; caspase 8; colorectal neoplasms; human KDM4B protein; mitochondria