title: Methylated alteration of SHP1 complements mutation of JAK2 tyrosine kinase in patients with myeloproliferative neoplasm.
abstract: SHP1 negatively regulates the Janus kinase 2/signal transducer and activator of transcription (JAK2/STAT) signaling pathway, which is constitutively activated in myeloproliferative neoplasms (MPNs) and leukemia. Promoter hypermethylation resulting in epigenetic inactivation of SHP1 has been reported in myelomas, leukemias and other cancers. However, whether SHP1 hypermethylation occurs in MPNs, especially in Chinese patients, has remained unclear. Here, we report that aberrant hypermethylation of SHP1 was observed in several leukemic cell lines and bone marrow mononuclear cells from MPN patients. About 51 of 118 (43.2%) MPN patients including 23 of 50 (46%) polycythaemia vera patients, 20 of 50 (40%) essential thrombocythaemia and 8 of 18 (44.4%) idiopathic myelofibrosis showed hypermethylation by methylation-specific polymerase chain reaction. However, SHP1 methylation was not measured in 20 healthy volunteers. Hypermethylation of SHP1 was found in MPN patients with both positive (34/81, 42%) and negative (17/37, 45.9%) JAK2V617F mutation. The levels of SHP1 mRNA were significantly lower in hypermethylated samples than unmethylated samples, suggesting SHP1 may be epigenetically inactivated in MPN patients. Furthermore, treatment with 5-aza-2'-deoxycytidine (AZA) in K562 cells showing hypermethylation of SHP1 led to progressive demethylation of SHP1, with consequently increased reexpression of SHP1. Meanwhile, phosphorylated JAK2 and STAT3 were progressively reduced. Finally, AZA increased the expression of SHP1 in primary MPN cells with hypermethylation of SHP1. Therefore, our data suggest that epigenetic inactivation of SHP1 contributes to the constitutive activation of JAK2/STAT signaling. Restoration of SHP1 expression by AZA may contribute to clinical treatment for MPN patients.
authors.affiliation: Department of Laboratory Medicine, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China E-mail : gaoshenmeng77@126.com.
authors.forename: Jun-Jun
authors.initials: JJ
authors.lastname: Yang
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.forename: Xiao-Qun
authors.initials: XQ
authors.lastname: Zheng
authors.forename: Hai-Ying
authors.initials: HY
authors.lastname: Li
authors.forename: Jian-Bo
authors.initials: JB
authors.lastname: Wu
authors.forename: Li-Yuan
authors.initials: LY
authors.lastname: Tang
authors.forename: Shen-Meng
authors.initials: SM
authors.lastname: Gao
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D001483:Base Sequence; D015153:Blotting, Western; D016022:Case-Control Studies; D019175:DNA Methylation; D000077209:Decitabine; D057890:Epigenomics; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D009196:Myeloproliferative Disorders / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050796:STAT3 Transcription Factor / Q000235:genetics*; D014407:Tumor Cells, Cultured
chemical_list: D000964:Antimetabolites, Antineoplastic; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D000077209:Decitabine; C507924:JAK2 protein, human; D053614:Janus Kinase 2; C509249:PTPN6 protein, human; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D001374:Azacitidine