title: Epigenetic modification and preliminary investigation of the mechanism of the immune evasion of HL-60 cells.
abstract: The aim of the present study was to explore the effect of epigenetic modification of class II transactivator (CIITA) methylation on histocompatibility complex (MHC) class II expression and the immune evasion of leukemia HL-60 cells. HL-60 cells were treated with various concentrations of 5-aza-2'deoxycytidine (5-Aza-CdR) and 0.5 µmol/l suberoylanilide hydroxamic acid (SAHA) for 24 h and then stimulated by interferon γ (IFN-γ) for 48 h. The mRNA levels of MHC class I, II and co-stimulatory molecules were quantified by reverse transcription polymerase chain reaction (RT-PCR). The levels of CIITA protein were determined by western blot analysis, and the CpG island methylation ratios in the CIITA promoter IV (CIITApIV) were analyzed by bisulfite-sequencing PCR (BSP). MHC I as well as the co-stimulatory molecules CD40 and CD80 were significantly increased following treatment with 5-Aza-CdR + SAHA + IFN-γ (epigenetic groups) compared with those in the control group and IFN-γ group (P<0.05). The expression of MHC class II and CIITA was restored and increased in an 5-Aza-CdR concentration-dependent manner in the three epigenetic groups. The results of the BSP assay showed that the methylation rate of CIITApIV CpG sites decreased with the treatment of epigenetic modification and negatively correlated to the 5-Aza-CdR concentration. This demonstrated that the negative expression of CIITA protein was the key reason for the loss of MHC II expression in HL-60 cells. The results of the present study may help to illustrate the mechanism of immune evasion in HL-60 cells.
authors: Department of Hematology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai 200240, P.R. China.
authors: Jin Hong
authors: JH
authors: Liu
authors: Department of Pediatrics, Minhang District Maternal and Child Health Care Hospital of Shanghai, Shanghai 201102, P.R. China.
authors: Yong Mei
authors: YM
authors: Bian
authors: Department of Hematology, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China.
authors: Yi
authors: Y
authors: Xie
authors: Department of Hematology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai 200240, P.R. China.
authors: Dao Pei
authors: DP
authors: Lu
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D018122:B7-1 Antigen / Q000235:genetics / Q000276:immunology; D019013:CD40 Antigens / Q000235:genetics / Q000276:immunology; D018899:CpG Islands; D019175:DNA Methylation; D000077209:Decitabine; D004305:Dose-Response Relationship, Drug; D044127:Epigenesis, Genetic / Q000187:drug effects / Q000276:immunology*; D018922:HL-60 Cells; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology; D009687:Nuclear Proteins / Q000235:genetics / Q000276:immunology*; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D015534:Trans-Activators / Q000235:genetics / Q000276:immunology*; D019139:Tumor Escape / Q000187:drug effects / Q000235:genetics*; D000077337:Vorinostat
chemical_list: D000964:Antimetabolites, Antineoplastic; D018122:B7-1 Antigen; D019013:CD40 Antigens; D006877:Hydroxamic Acids; C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; D015534:Trans-Activators; D000077337:Vorinostat; D000077209:Decitabine; D007371:Interferon-gamma; D001374:Azacitidine