title: Contragestazol (DL111-IT) inhibits proliferation of human androgen-independent prostate cancer cell line PC3 in vitro and in vivo.
abstract: OBJECTIVE
  To evaluate the antiproliferative activity of contragestazol (DL111-IT) on the human prostate cancer cell line PC3 in vitro and in vivo and to elucidate its potential molecular mechanisms.
  
  
  METHODS
  The cell killing ability of DL111-IT was measured by the 3-(4,5-dimethylthia-zol,2-yl)-2,5-diphenyltetrazolium bromide (MTT) reagent assay method and the tumor xenograft model. The cell cycle was analyzed by flow cytometry and protein expression, including retinoblastoma (pRb), cyclin-dependent kinase 4 (CDK4) and cyclin D1, was detected by Western blotting.
  
  
  RESULTS
  DL111-IT exhibited high efficiency on cell growth inhibition of the human androgen-independent prostate cancer cell line PC3. The drug concentration that yielded 50% cell inhibition (IC50 value) was 9.9 mg/mL. In the PC3 tumor xenograft study, DL111-IT (1.25 mg/kg-20.0 mg/kg) given once a day for 10 days significantly inhibited tumor growth, with the inhibition rate ranging from 21% to 50%. Flow cytometric analysis indicated that DL111-IT could cause G1 arrest in the PC3 cell line, but not apoptosis. DL111-IT enhanced pRb expression and down-regulated CDK4 and cyclin D1 expression, suggesting that cell cycle regulation might contribute to the anticancer property of DL111-IT.
  
  
  CONCLUSIONS
  DL111-IT inhibits the proliferation of human androgen-independent prostate cancer cell line PC3 in vitro and in vivo by a cell cycle regulation pathway.
authors.affiliation: Department of Pharmacology, College of Pharmaceutical Science, Zhejiang University, 353 YanAn Road, Hangzhou 310031, China.
authors.forename: Qiao-Jun
authors.initials: QJ
authors.lastname: He
authors.forename: Bo
authors.initials: B
authors.lastname: Yang
authors.forename: Yi-Jia
authors.initials: YJ
authors.lastname: Lou
authors.forename: Rui-Ying
authors.initials: RY
authors.lastname: Fang
mesh_terms: D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D019938:Cyclin D1 / Q000378:metabolism; D051358:Cyclin-Dependent Kinase 4 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D016193:G1 Phase / Q000187:drug effects; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D016160:Retinoblastoma Protein / Q000378:metabolism; D014183:Transplantation, Heterologous; D014230:Triazoles / Q000494:pharmacology*
chemical_list: D000728:Androgens; D007166:Immunosuppressive Agents; D016160:Retinoblastoma Protein; D014230:Triazoles; D019938:Cyclin D1; C030266:3-(2-ethylphenyl)-5-(3-methoxyphenyl)-1H-1,2,4-triazole; D051358:Cyclin-Dependent Kinase 4