title: Radiosensitization of hormone-refractory prostate cancer cells by gossypol treatment.
abstract: OBJECTIVE
  many drugs have been tested to increase the sensitivity of prostate cancer cells to radiotherapy. Gossypol, a natural polyphenolic compound extracted from the cotton plant, is one of the agents the efficacy of which has been investigated in the treatment of prostate cancer for this purpose. The main aim of this study was to investigate the best gossypol application with irradiation, when gossypol was applied either sequentially (24 h before and after irradiation) or concurrently in PC-3 hormone-refractory and radioresistant prostate cancer cells.
  
  
  METHODS
  The XTT viability assay was used to evaluate the cytotoxicity of different concentrations of gossypol in PC- 3 cells. Irradiation was applied to PC-3 cells via 6 MV photon linear accelerator and delivered 24 h before, 24 h after radiation or at the same time with gossypol administration.
  
  
  RESULTS
  gossypol caused radiosensitization of PC-3 cells that are known to be radioresistant, with high Bcl-2 levels. Among different applications of gossypol and irradiation (before, after and concurrent) in prostate cancer cells, the best results were observed by the application of gossypol 24 h before irradiation.
  
  
  CONCLUSIONS
  our study suggests that gossypol represents a promising novel anticancer treatment for radiosensitization of human hormone-refractory prostate cancer cells.
authors.affiliation: Division of Radiation Oncology, School of Medicine, Ege University, Bornova, Izmir, Turkey.
authors.forename: O
authors.initials: O
authors.lastname: Akagunduz
authors.forename: B
authors.initials: B
authors.lastname: Karaca
authors.forename: H
authors.initials: H
authors.lastname: Atmaca
authors.forename: S
authors.initials: S
authors.lastname: Uzunoglu
authors.forename: B
authors.initials: B
authors.lastname: Karabulut
authors.forename: U A
authors.initials: UA
authors.lastname: Sanli
authors.forename: A
authors.initials: A
authors.lastname: Haydaroglu
authors.forename: R
authors.initials: R
authors.lastname: Uslu
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D003131:Combined Modality Therapy; D003272:Contraceptive Agents, Male / Q000627:therapeutic use*; D005720:Gamma Rays; D006072:Gossypol / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D011836:Radiation Tolerance / Q000187:drug effects*; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D003272:Contraceptive Agents, Male; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D011838:Radiation-Sensitizing Agents; D006072:Gossypol