title: [Promotive effect of decreased cyclin E threshold on cell proliferation].
abstract: OBJECTIVE
  Many studies showed that high expression of Cyclin E promotes cell proliferation, but contrary data was also reported that cell proliferation didn't decrease with low expression of Cyclin E. In addition, we observed that many tumor cells have strong capability of proliferation with low expression of Cyclins, including Cyclin E. This study was to analyze effect of reduced Cyclin E threshold on proliferation of acute lymphocyte leukemia cell line MOLT-4 to explain the above phenomena.
  
  
  METHODS
  We have established the model of decreased Cyclin E threshold in MOLT-4 cells by treating cells with low concentration (5 mmol/L) of caffeine for 2, and 4 h. The positive rates of proliferation cell nuclear antigen (PCNA), Ki67, and DNA strand break induction by photolysis (SBIP) were analyzed by flow cytometry.
  
  
  RESULTS
  MOLT-4 cells presented sharply decrease of Cyclin E threshold, and increase of positive rates of PCNA, Ki67, and SBIP after treated with caffeine, especially at 2-h point.
  
  
  CONCLUSIONS
  Decrease of Cyclin E threshold was accompanied by increase of cell proliferation. MOLT-4 cells may remain high proliferation capability with low level of Cyclin expression.
authors.affiliation: Center of Gastroenterological Surgery/Cancer Research Institute, Tongji Hospital, Tongji Medical College, University of Huazhong Science and Technology, Wuhan, Hubei 430 030, P.R. China.
authors.forename: Ji-Chao
authors.initials: JC
authors.lastname: Qin
authors.forename: Xiao-Xi
authors.initials: XX
authors.lastname: Chen
authors.forename: De-Ding
authors.initials: DD
authors.lastname: Tao
authors.forename: Yong-Dong
authors.initials: YD
authors.lastname: Feng
authors.forename: Jun-Bo
authors.initials: JB
authors.lastname: Hu
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Gong
mesh_terms: D002110:Caffeine / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D019927:Cyclin E / Q000096:biosynthesis* / Q000235:genetics; D015536:Down-Regulation / Q000187:drug effects; D016193:G1 Phase; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism
chemical_list: D019927:Cyclin E; D019394:Ki-67 Antigen; D018809:Proliferating Cell Nuclear Antigen; D002110:Caffeine