title: SPAG6 silencing inhibits the growth of the malignant myeloid cell lines SKM-1 and K562 via activating p53 and caspase activation-dependent apoptosis.
abstract: SPAG6, which is a novel cancer-testis antigen, is overexpressed in myeloid malignancies. Previously, SPAG6 was found in UPD (uniparental disomy) region of myeloid cell DNA from MDS patients and reported that SPAG6 may be a predictive marker of minimal residual disease in pediatric acute myeloid, but the biological role of SPAG6 in myeloid malignancies remains unclear. The present study was undertaken to determine the expression and functional significance of SPAG6 in malignant myeloid hematologic cell lines. A short hairpin RNA (shRNA) targeting SPAG6 was designed that could specifically inhibit SPAG6 expression at the mRNA and protein levels when introduced into the malignant myeloid hematologic cell lines SKM-1 and K562. The results from flow cytometry and CCK-8 assays showed that SPAG6 silencing inhibited the proliferation of SKM-1/K562 by inducing apoptosis. Furthermore, SPAG6 silencing resulted in activation of caspase-3, -9 and -8 and upregulated the mRNA and protein expression of p53 and PTEN. Then, we subcutaneously inoculated the monoclonal cells into NOD/SCID mice to establish xenograft models, and we found that the SPAG6-shRNA lentivirus dramatically inhibited tumor growth and increased apoptosis in vivo. These findings demonstrate that SPAG6 might have a role in malignant myeloid hematologic cell proliferation and apoptosis by regulating caspase proteins and p53, suggesting that SPAG6 may be a potential therapeutic target.
authors.affiliation: Department of Hematology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Bihui
authors.initials: B
authors.lastname: Yang
authors.affiliation: Department of Hematology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Hematology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Luo
authors.affiliation: Department of Hematology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Liping
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Hematology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Zesong
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Department of Hematology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Lin
authors.initials: L
authors.lastname: Liu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D020169:Caspases / Q000096:biosynthesis; D049109:Cell Proliferation / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D006801:Humans; D020014:K562 Cells; D051379:Mice; D008868:Microtubule Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D009190:Myelodysplastic Syndromes / Q000235:genetics* / Q000473:pathology; D022423:Myeloid Cells / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis*; D023041:Xenograft Model Antitumor Assays
chemical_list: D008868:Microtubule Proteins; C400106:SPAG6 protein, human; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D020169:Caspases