title: Molecular mechanism of prostate cancer cell apoptosis induced by busulfan via adjustment of androgen receptor phosphatization.
abstract: OBJECTIVE
  To probe killing effect of busulfan to prostate cancer cell without androgen and the influence of androgen receptor phosphatization and analyze its molecular mechanism.
  
  
  METHODS
  prostate cancer cell line 22RV1, LAPC4 and LNCaP treated with busulfan under androgen-free condition underwent CCK-8 examination to probe killing ability of the medicine. Flow cytometry was used to check the influence of busulfan on apoptosis rate of prostate cancer cell line LAPC4. Expression level of androgen receptor (AR), Src and Ack1 and change in phosphatization of AR after busulfan treatment were measured by RT-PCR and Western blotting. Finally, influence o proliferation ability and apoptosis of LAPC4 were measured using EGF-busulfan co-processing.
  
  
  RESULTS
  Significant dose-dependency was observed as killing ability rises with higher busulfan concentration (p<0.05). Significant improvement in prostate cancer cell inhibition ability of busulfan was also observed with prolonging of time (p<0.05). Then we discovered, as indicated by flow cytometry, that busulfan inhibits prostate cancer cell LAPC4 proliferation by strengthening its apoptosis (p<0.05), which showed significant dose- and time-dependency. Detection of AR expression and phosphatization level showed no significant influence on mRNA and protein expression level of AR made by busulfan. However, decline of phosphatization level at AR Y534 site was positively related to busulfan treatment time. Busulfan was found to be inhibitory to Src kinase induced by EGF and level of resulting AR phosphatization in our further probe into the mechanism of busulfan influence on phosphatization level at AR Y534 site. Nude mice experiment indicated that busulfan was inhibitory to protein expression of AR downstream target gene prostate specific antigen (PSA) and human tissue kallikrein2 (hk-2), thus inhibited in vivo tumorigenic ability of prostate cancer cells.
  
  
  CONCLUSIONS
  Busulfan was significantly inhibitory to prostate cancer cell proliferation by inhibiting phosphatization of Src kinase at AR Y534 site.
authors.affiliation: Department of Clinical Laboratory, Zhejiang Xiaoshan Hospital Hangzhou, Zhejiang 311201, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Pharmacy, Zhejiang Xiaoshan Hospital Hangzhou, Zhejiang 311201, China.
authors.forename: Guojun
authors.initials: G
authors.lastname: Jiang
authors.affiliation: Department of Clinical Laboratory, Zhejiang Xiaoshan Hospital Hangzhou, Zhejiang 311201, China.
authors.forename: Aiping
authors.initials: A
authors.lastname: Yang
authors.affiliation: Department of Clinical Laboratory, Zhejiang Xiaoshan Hospital Hangzhou, Zhejiang 311201, China.
authors.forename: Guohui
authors.initials: G
authors.lastname: Yang
authors.affiliation: Department of Clinical Laboratory, Zhejiang Xiaoshan Hospital Hangzhou, Zhejiang 311201, China.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Yang
authors.affiliation: Department of Urology, Zhejiang Xiaoshan Hospital Hangzhou, Zhejiang 311201, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Fang
keywords: Busulfan; Src kinase; androgen receptor; phosphatization; tyrosine kinase