title: High expression of APAF-1 elevates erythroid apoptosis in iron overload myelodysplastic syndrome.
abstract: Apoptotic protease-activating factor 1 (APAF-1) is a central component of the intrinsic pathway of apoptosis. Our study aims at searching the role of APAF-1 in iron overload myelodysplastic syndrome (MDS). Erythroid apoptosis rate, mRNA expression levels of APAF-1, and caspase-9 activity were determined by flow cytometry, quantitative real-time PCR, and colorimetric assay in MDS patients, respectively. In addition, K562 and MDS-L cell lines were incubated with different concentrations of ferric ammonium citrate (FAC) or ferric ammonium citrate + desferrioxamine (FAC + DFO) in vitro to observe the alteration in erythrocyte apoptosis rate, APAF-1 mRNA, and protein expression levels. Moreover, as control, erythroid apoptosis rate and APAF-1 mRNA expression were detected after silencing APAF-1 expression by endoribonuclease-prepared small interfering RNAs (esiRNAs) in K562 and MDS-L cell lines. Both erythroid apoptosis rate and APAF-1 mRNA expression of the iron overload (IO) group were significantly higher than those of the non-IO group (P < 0.001 and P < 0.001). There is a significant difference of caspase-9 activity between the IO group and the non-IO group (P < 0.001). Erythroid apoptosis rate and APAF-1 mRNA expression of K562 and MDS-L cell lines significantly elevated after FAC incubation in different concentrations (P < 0.001 and P < 0.001 for K562; P < 0.001 and P < 0.001 for MDS-L), while erythroid apoptosis rate and APAF-1 mRNA expression in the FAC + DFO group declined (P < 0.001 and P < 0.001 for K562; P < 0.001 and P < 0.001 for MDS-L). After silencing of APAF-1 expression with specific esiRNAs, erythroid apoptosis rate and APAF-1 mRNA expression of K562 and MDS-L cell lines markedly decreased (P < 0.001 and P < 0.001 for K562; P < 0.001 and P < 0.001 for MDS-L). APAF-1 plays an important role in iron-induced erythroid apoptosis increase in MDS.
authors.affiliation: Department of Hematology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiaotong University, No.600, Yi Shan Road, Shanghai, 200233, China.
authors.forename: Shucheng
authors.initials: S
authors.lastname: Gu
authors.forename: Youshan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Juan
authors.initials: J
authors.lastname: Guo
authors.forename: Feng
authors.initials: F
authors.lastname: Xu
authors.forename: Chengming
authors.initials: C
authors.lastname: Fei
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.forename: Chao
authors.initials: C
authors.lastname: Xiao
authors.forename: Chunkang
authors.initials: C
authors.lastname: Chang
authors.forename: Xiao
authors.initials: X
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000502:physiology*; D053477:Apoptotic Protease-Activating Factor 1 / Q000378:metabolism*; D015153:Blotting, Western; D002469:Cell Separation; D004912:Erythrocytes / Q000473:pathology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D019190:Iron Overload / Q000150:complications / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000150:complications / Q000378:metabolism* / Q000473:pathology; D034741:RNA, Small Interfering; D060888:Real-Time Polymerase Chain Reaction; D055815:Young Adult
chemical_list: C506592:APAF1 protein, human; D053477:Apoptotic Protease-Activating Factor 1; D034741:RNA, Small Interfering