title: [Inhibitory Effect of High Concentration Insulin on K562 Cell Proliferation and Its Mechanism].
abstract: OBJECTIVE
  To investigate the inhibitory effect of high concentration insulin on K562 cell proliferation and its underlying mechanism.
  
  
  METHODS
  K562 cells were treated by different concentration of insulin and/or anti-IGF-1R antibody (IGF-1R-Ab), MTT assay and flow cytometry were used to detect the K562 cells proliferation and apoptosis, respectivety; Western blot was used to measure the expression and phosphorylation level of IGE-IR, Akt, Erk1/2 in K562 cells under the different concentration of insulin.
  
  
  RESULTS
  MTT assay showed that less than 40 mU/ml insulin could promote K562 cell proliferation, while high concentration (> 40 mU/ml) insulin has been shown to inhibit K562 cell proliferation; Flow cytometry showed that 40 mU/ml insulin suppressed K562 cell apoptosis (P < 0.05), while 200 mU/ml insulin could significantly induce K562 cell apoptosis (P < 0.01); 0.01 to 1.0 µg/ml IGF-1R-Ab has significantly enhanced the inhibitory and inducing effects of high concentration (> 40 mU/ml) of insulin on K562 cell proliferation and apoptosis respectively (r = 0.962, P < 0.001); Western blot showed that after K562 cells were treated with different concentrations of insulin ERK, and the p-ERK expression did not change significantly, after K562 cells were treated with 200 mU/ml insulin, the expression of IGF-1R and AKT also not were changed obviously, while the phosphorylation level of IGF-1R and AKT increased.
  
  
  CONCLUSIONS
  High concentration (>40 mU/ml) of insulin inhibits K562 cell proliferation and induces its apoptosis, and its mechanism may be related with the binding IGF-1R by insulin, competitively inhibiting the binding of IGF-1 and IGF-1R, the blocking the transduction of PI3K/AKT signal pathway.
authors.affiliation: Department of Hematology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou 362000, Fujian Province, China.
authors.forename: Yue-Qin
authors.initials: YQ
authors.lastname: Huang
authors.affiliation: Department of Colorectal Surgery, Beijing Cancer Hospital, Beijing 100142, China.
authors.forename: Hong-Da
authors.initials: HD
authors.lastname: Pan
authors.affiliation: Department of Genetics, Zhongshan Medical College of Zhongshan University, Guangzhou 510080, Guangdong Province, China.
authors.forename: Yi-Bin
authors.initials: YB
authors.lastname: Guo
authors.affiliation: Department of Hematology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou 362000, Fujian Province, China. E-mail: onlyonepjx@aliyun.com.
authors.forename: Jing-Xin
authors.initials: JX
authors.lastname: Pan
mesh_terms: D000906:Antibodies / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D003470:Culture Media / Q000737:chemistry; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D020014:K562 Cells; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017451:Receptors, Somatomedin / Q000276:immunology; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D000906:Antibodies; D003470:Culture Media; D007328:Insulin; D017451:Receptors, Somatomedin; D007334:Insulin-Like Growth Factor I; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D048052:Mitogen-Activated Protein Kinase 3