title: FTY720 mediates activation suppression and G(0)/G          (1) cell cycle arrest in a concanavalin A-induced mouse lymphocyte pan-activation model.
abstract: OBJECTIVE
  FTY720 is a potent drug for multiple sclerosis treatment. To biologically address its possible applications to more generalized diseases with aberrant inflammation, we are testing whether FTY720 can function as a lymphocyte cell cycle blocker and activation suppressor via a concanavalin A (ConA)-mediated mouse lymphocyte pan-activation model.
  
  
  METHODS
  Mouse lymphocytes were obtained from lymph nodes and subjected to ConA and/or FTY720 treatment. Cell viability was assayed by MTT and mitochondrial assays. Early and late activation, cell cycle, proliferation and intracellular Ca(2+) concentration ([Ca(2+)](i)) were analyzed by flow cytometry.
  
  
  RESULTS
  At concentrations of less than 500 nM, FTY720 significantly down-regulated both CD69 and CD25 expressions of T cells, as well as inhibiting proliferation of activated lymphocytes. In addition, FTY720 blocked the ConA-induced mitogenesis, exhibiting lymphocyte G(0)/G(1) phase cell cycle arrest with significant reduction of cells in S and G(2)/M phases. Meanwhile, a significant decline in [Ca(2+)](i) was observed. The correlation of [Ca(2+)](i) and cell cycle arrest were validated by employing a [Ca(2+)](i) inhibitor SK&F 96365 and testing with and without FTY720 treatment.
  
  
  CONCLUSIONS
  We demonstrated that FTY720 induces G(0)/G(1) phase cell cycle arrest, resulting in proliferation inhibition upon lymphocyte pan-activation, which may be related to reduction of overall intracellular Ca(2+) load.
authors.affiliation: Institute for Tissue Transplantation and Immunology, Jinan University, Guangzhou, Guangdong, 510632, China.
authors.forename: Xiangfeng
authors.initials: X
authors.lastname: Zeng
authors.forename: Tong
authors.initials: T
authors.lastname: Wang
authors.forename: Cairong
authors.initials: C
authors.lastname: Zhu
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Ye
authors.forename: Bing
authors.initials: B
authors.lastname: Song
authors.forename: Xinqiang
authors.initials: X
authors.lastname: Lai
authors.forename: Yaoying
authors.initials: Y
authors.lastname: Zeng
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003208:Concanavalin A / Q000276:immunology; D015536:Down-Regulation; D005260:Female; D000068876:Fingolimod Hydrochloride; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology; D037181:Lectins, C-Type / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011409:Propylene Glycols / Q000494:pharmacology*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D003208:Concanavalin A; D000068876:Fingolimod Hydrochloride; D007166:Immunosuppressive Agents; D053645:Interleukin-2 Receptor alpha Subunit; D037181:Lectins, C-Type; D011409:Propylene Glycols; D013110:Sphingosine; D000099192:CD69 Antigens; C508018:Il2ra protein, mouse