title: Anti-tumor effects of a recombinant anti-prostate specific membrane antigen immunotoxin against prostate cancer cells.
abstract: BACKGROUND
  To evaluate anti-prostate cancer effects of a chimeric tumor-targeted killer protein.
  
  
  METHODS
  We established a novel fusion gene, immunocasp-3, composed of NH2-terminal leader sequence fused with an anti-prostate-specific membrane antigen (PSMA) antibody (J591), the furin cleavage sequences of diphtheria toxin (Fdt), and the reverse coding sequences of the large and small subunits of caspase-3 (revcaspase-3). The expressing level of the immunocasp-3 gene was evaluated by using the reverse transcription-PCR (RT-PCR) and western blot analysis. Cell viability assay and cytotoxicity assay were used to evaluate its anti-tumor effects in vitro. Apoptosis was confirmed by electron microscopy and Annexin V-FITC staining. The antitumor effects of immunocasp-3 were assessed in nude mice xenograft models containing PSMA-overexpressing LNCaP cells.
  
  
  RESULTS
  This study shows that the immunocasp-3 proteins selectively recognized and induced apoptotic death in PSMA-overexpressing LNCaP cells in vitro, where apoptotic cells were present in 15.3% of the cells transfected with the immunocasp-3 expression vector at 48 h after the transfection, in contrast to 5.5% in the control cells. Moreover, LNCaP cells were significantly killed under the condition of the co-culture of the immunocasp-3-secreting Jurkat cells and more than 50% of the LNCaP cells died when the two cell lines were co-cultured within 5 days. In addition, The expression of immunocasp-3 also significantly suppressed tumor growth and greatly prolonged the animal survival rate in vivo.
  
  
  CONCLUSIONS
  A novel fusion gene, immunocasp-3, may represent a viable approach to treating PSMA-positive prostate cancer.
authors.affiliation: Department of Urology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Meng
authors.affiliation: Department of Urology Surgery, Peoples' Hospital of Shaanxi Province, Xi'an, Shaanxi, China.
authors.forename: Qing-Chuan
authors.initials: QC
authors.lastname: Dong
authors.affiliation: Department of Pharmaceutical Analysis, School of Pharmacy, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Guang-Guo
authors.initials: GG
authors.lastname: Tan
authors.affiliation: Department of Immunology, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Wei-Hong
authors.initials: WH
authors.lastname: Wen
authors.affiliation: Department of Urology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: He
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Urology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Geng
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Urology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Yan-Zhu
authors.initials: YZ
authors.lastname: Wang
authors.affiliation: Department of Urology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Yu-Ming
authors.initials: YM
authors.lastname: Jing
authors.affiliation: State Key Laboratory of NBC Protection for Civilian, Beijing, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Urology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China. weijunqfmmu@163.com.
authors.forename: Wei-Jun
authors.initials: WJ
authors.lastname: Qin
authors.affiliation: Department of Urology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China. jianliny@fmmu.edu.cn.
authors.forename: Jian-Lin
authors.initials: JL
authors.lastname: Yuan
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000628:therapy*; D000818:Animals; D000954:Antigens, Surface / Q000235:genetics; D019677:Artificial Gene Fusion; D053148:Caspase 3 / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods; D043425:Glutamate Carboxypeptidase II / Q000235:genetics; D006801:Humans; D000922:Immunotoxins / Q000235:genetics; D008297:Male; D008819:Mice, Nude; D011471:Prostatic Neoplasms / Q000473:pathology / Q000628:therapy*; D014407:Tumor Cells, Cultured
chemical_list: D000954:Antigens, Surface; D000922:Immunotoxins; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II; D053148:Caspase 3
keywords: Apoptosis; Gene therapy; Prostate cancer; Prostate-specific membrane antigen; Recombinant protein