title: Direct intra-tumoral injection of zinc-acetate halts tumor growth in a xenograft model of prostate cancer.
abstract: Intracellular levels of zinc have shown a strong inverse correlation to growth and malignancy of prostate cancer. To date, studies of zinc supplementation in prostate cancer have been equivocal and have not accounted for bioavailability of zinc. Therefore, we hypothesized that direct intra-tumoral injection of zinc could impact prostate cancer growth. In this study, we evaluated the cytotoxic properties of the pH neutral salt zinc acetate on the prostate cancer cell lines PC3, DU145 and LNCaP. Zinc acetate killed prostate cancer cell lines in vitro, independent of androgen sensitivity, in a dose-dependent manner in a range between 200 and 600 microM. Cell death occurred rapidly with 50% cell death by six hours and maximal cell death by 18 hours. We next established a xenograft model of prostate cancer and tested an experimental treatment protocol of direct intra-tumoral injection of zinc acetate. We found that zinc treatments halted the growth of the prostate cancer tumors and substantially extended the survival of the animals, whilst causing no detectable cytoxicity to other tissues. Thus, our studies form a solid proof-of-concept that direct intra-tumoral injection of zinc acetate could be a safe and effective treatment strategy for prostate cancer.
authors.affiliation: Department of Otolaryngology, Saint Louis University, Saint Louis, Missouri, USA. shahmr@slu.edu
authors.forename: Maulik R
authors.initials: MR
authors.lastname: Shah
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Kriedt
authors.forename: Nathan H
authors.initials: NH
authors.lastname: Lents
authors.forename: Mary K
authors.initials: MK
authors.lastname: Hoyer
authors.forename: Nimah
authors.initials: N
authors.lastname: Jamaluddin
authors.forename: Claudette
authors.initials: C
authors.lastname: Klein
authors.forename: Joseph
authors.initials: J
authors.lastname: Baldassare
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D006801:Humans; D015552:Injections, Intralesional; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy* / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays; D019345:Zinc Acetate / Q000008:administration & dosage*
chemical_list: D019345:Zinc Acetate