title: 213Bi-PAI2 conjugate selectively induces apoptosis in PC3 metastatic prostate cancer cell line and shows anti-cancer activity in a xenograft animal model.
abstract: A novel alpha-particle emitting ((213)Bi) plasminogen activator inhibitor type 2 construct, which targets the membrane-bound urokinase plasminogen activator on prostate cancer cells, was prepared and evaluated in vitro and in a xenograft animal model. The PC3 prostate cancer cell line expresses urokinase plasminogen activator which binds to its receptor on the cell membrane; plasminogen activator inhibitor type 2 is bound to urokinase plasminogen activator/urokinase plasminogen activator receptor to form stable complexes. In vitro, the cytotoxicity of (213)Bi-plasminogen activator inhibitor type 2 against prostate cancer cells was tested using the MTS assay and apoptosis was documented using terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labelling (TUNEL) assay. In vivo, antiproliferative effects for tumours and prostate cancer lymph node metastasis were carried out in an athymic nude mouse model with a subcutaneous xenograft of PC3 cells. (213)Bi-plasminogen activator inhibitor type 2 was specifically cytotoxic to PC3 cells in a concentration-dependent fashion, causing the cells to undergo apoptosis. A single local or i.p. injection of (213)Bi-plasminogen activator inhibitor type 2 was able to completely regress the growth of tumours and lymph node metastases 2 days post subcutaneous inoculation, and obvious tumour regression was achieved in the therapy groups compared with control groups with (213)Bi-plasminogen activator inhibitor type 2 when the tumours measured 30-40 mm(3) and 85-100 mm(3). All control animals and one of five (20%) mice treated with 3 mCi kg(-1) (213)Bi-plasminogen activator inhibitor type 2 developed metastases in the lymph nodes while no lymphatic spread of cancer was found in the 6 mCi kg(-1) treated groups at 2 days and 2 weeks post-cell inoculation. These results demonstrate that this novel (213)Bi-plasminogen activator inhibitor type 2 conjugate selectively targets prostate cancer in vitro and in vivo, and could be considered for further development for the therapy of prostate cancer, especially for the control of micro-metastases or in minimal residual disease.
authors.affiliation: Center for Experimental Radiation Oncology, Cancer Care Center, St George Hospital, Gray St, Kogarah 2217, NSW, Australia.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: S M A
authors.initials: SM
authors.lastname: Rizvi
authors.forename: M
authors.initials: M
authors.lastname: Ranson
authors.forename: B J
authors.initials: BJ
authors.lastname: Allen
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001729:Bismuth / Q000494:pharmacology*; D006801:Humans; D007279:Injections, Subcutaneous; D008207:Lymphatic Metastasis; D008297:Male; D051379:Mice; D008819:Mice, Nude; D017396:Plasminogen Activator Inhibitor 2 / Q000494:pharmacology*; D011471:Prostatic Neoplasms / Q000473:pathology*; D011868:Radioisotopes / Q000494:pharmacology*; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured
chemical_list: D017396:Plasminogen Activator Inhibitor 2; D011868:Radioisotopes; D001729:Bismuth