title: Novel titanocene anti-cancer drugs and their effect on apoptosis and the apoptotic pathway in prostate cancer cells.
abstract: Advanced prostate cancer is not curable by current treatment strategies indicating a significant need for new chemotherapeutic options. Highly substituted ansa-titanocene compounds have shown promising cytotoxic activity in a range of cancers. The objectives of this study are to examine the effects of these titanocene compounds on prostate cancer cells. Prostate cell lines were treated with three novel titanocene compounds and compared to titanocene dichloride and cisplatin. Percent apoptosis, viability and cell cycle were assessed using propidium iodide DNA incorporation with flow cytometry. Cytochrome C was assessed by western blotting of mitochondrial and cytoplasmic fractions. Apoptosis Inducing Factor was assessed by confocal microscopy. These novel compounds induced more apoptosis compared to cisplatin in a dose dependent manner. Compound Y had the most significant effect on cell cycle and apoptosis. Despite the release of cytochrome C from the mitochondrial fraction there was no inhibition of apoptosis with the pan caspase inhibitor, ZVAD-FMK. AIF was shown to translocate from the cytosol to the nucleus mediating a caspase independent cell death. Bcl-2 over expressing PC-3 cells, which were resistant to cisplatin induced apoptosis, underwent apoptosis following treatment with all the titanocene compounds. This study demonstrates possible mechanisms by which these novel titanocene compounds can mediate their apoptotic effect in vitro. The fact that they can induce more apoptosis than cisplatin in advanced cancer cell lines would confer an advantage over cisplatin. They represent exciting new agents with future potential for the treatment of advanced prostate cancer.
authors.affiliation: UCD School of Medicine and Medical Sciences, Mater Misericordiae University Hospital, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: K
authors.initials: K
authors.lastname: O'Connor
authors.forename: C
authors.initials: C
authors.lastname: Gill
authors.forename: M
authors.initials: M
authors.lastname: Tacke
authors.forename: F-J K
authors.initials: FJ
authors.lastname: Rehmann
authors.forename: K
authors.initials: K
authors.lastname: Strohfeldt
authors.forename: N
authors.initials: N
authors.lastname: Sweeney
authors.forename: J M
authors.initials: JM
authors.lastname: Fitzpatrick
authors.forename: R W G
authors.initials: RW
authors.lastname: Watson
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D051033:Apoptosis Inducing Factor / Q000378:metabolism; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D045304:Cytochromes c / Q000378:metabolism; D006801:Humans; D008297:Male; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry / Q000494:pharmacology*; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: C507877:(1,2-di(cyclopentadienyl)-1,2-di(3-dimethoxyphenyl)ethanediyl)titanium dichloride; D000590:Amino Acid Chloromethyl Ketones; D000970:Antineoplastic Agents; D051033:Apoptosis Inducing Factor; D015853:Cysteine Proteinase Inhibitors; D009942:Organometallic Compounds; D019253:Proto-Oncogene Proteins c-bcl-2; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C507878:bis((4-methoxybenzyl)cyclopentadienyl)titanium(IV) dichloride; C406884:titanocene; D045304:Cytochromes c; D002945:Cisplatin