title: The hyposensitive N187D P2X7 mutant promotes malignant progression in nude mice.
abstract: Nucleotides are new players in the intercellular communication network. P2X7 is a member of the P2X family of receptors, which are ATP-gated plasma membrane ion channels with diverse biological functions. Abnormal expression and dysfunction of P2X7 have been reported in leukemias. Here, we report a new P2X7 mutant (an A(559)-to-G substitution causing N187D P2X7) cloned from J6-1 leukemia cells. The characteristics of N187D P2X7 were studied by establishing stably transfected K562 cell lines. Our results show that N187D P2X7 required a higher concentration of agonist for its activation, leading to Ca(2+) influx (EC(50) = 293.3 ± 6.6 μm for the mutant and 93.6 ± 2.2 μm for wild-type P2X7) and ERK phosphorylation, which were not caused by differential cell-surface expression or related to high ATPase activity on the cell surface and in the extracellular space. K562 cells expressing this N187D mutant showed a proliferative advantage and reduced pro-apoptosis effects in vitro and in vivo. Furthermore, elevated angiogenesis and CD206-positive macrophage infiltration were found in tumor tissues formed by K562-M cells. In addition, higher expression of VEGF and MCP1 could be detected in tumor tissues formed by K562-M cells. Our results suggest that N187D P2X7, representing mutants hyposensitive to agonist, might be a positive regulator in the progression of hematopoietic malignancies.
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 288 Nanjing Road, Tianjin 300020, China.
authors.forename: Jing-Hui
authors.initials: JH
authors.lastname: Chong
authors.forename: Guo-Guang
authors.initials: GG
authors.lastname: Zheng
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Ma
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Zhang
authors.forename: Kun
authors.initials: K
authors.lastname: Nie
authors.forename: Yong-Min
authors.initials: YM
authors.lastname: Lin
authors.forename: Ke-Fu
authors.initials: KF
authors.lastname: Wu
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D018450:Disease Progression; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D020014:K562 Cells; D007942:Leukemia, Experimental / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D020125:Mutation, Missense; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D058486:Receptors, Purinergic P2X7 / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014183:Transplantation, Heterologous; D047368:Tumor Burden / Q000235:genetics; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D058486:Receptors, Purinergic P2X7; C033901:3'-O-(4-benzoyl)benzoyladenosine 5'-triphosphate; D000255:Adenosine Triphosphate; D048051:p38 Mitogen-Activated Protein Kinases; D002118:Calcium