title: Intratumoral delivery of beta-lapachone via polymer implants for prostate cancer therapy.
abstract: OBJECTIVE
  beta-Lapachone (ARQ 501, a formulation of beta-lapachone complexed with hydroxypropyl-beta-cyclodextrin) is a novel anticancer agent with selectivity against prostate cancer cells overexpressing the NAD(P)H:quinone oxidoreductase-1 enzyme. Lack of solubility and an efficient drug delivery strategy limits this compound in clinical applications. In this study, we aimed to develop beta-lapachone-containing polymer implants (millirods) for direct implantation into prostate tumors to test the hypothesis that the combination of a tumor-specific anticancer agent with site-specific release of the agent will lead to significant antitumor efficacy.
  
  
  METHODS
  Survival assays in vitro were used to test the killing effect of beta-lapachone in different prostate cancer cells. beta-Lapachone release kinetics from millirods was determined in vitro and in vivo. PC-3 prostate tumor xenografts in athymic nude mice were used for antitumor efficacy studies in vivo.
  
  
  RESULTS
  beta-Lapachone killed three different prostate cancer cell lines in an NAD(P)H:quinone oxidoreductase-1-dependent manner. Upon incorporation of solid-state inclusion complexes of beta-lapachone with hydroxypropyl-beta-cyclodextrin into poly(D,L-lactide-co-glycolide) millirods, beta-lapachone release kinetics in vivo showed a burst release of approximately 0.5 mg within 12 hours and a subsequently sustained release of the drug ( approximately 0.4 mg/kg/d) comparable with that observed in vitro. Antitumor efficacy studies showed significant tumor growth inhibition by beta-lapachone millirods compared with controls (P < 0.0001; n = 10 per group). Kaplan-Meier survival curves showed that tumor-bearing mice treated with beta-lapachone millirods survived nearly 2-fold longer than controls, without observable systemic toxicity.
  
  
  CONCLUSIONS
  Intratumoral delivery of beta-lapachone using polymer millirods showed the promising therapeutic potential for human prostate tumors.
authors.affiliation: Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Dong
authors.forename: Shook-Fong
authors.initials: SF
authors.lastname: Chin
authors.forename: Elvin
authors.initials: E
authors.lastname: Blanco
authors.forename: Erik A
authors.initials: EA
authors.lastname: Bey
authors.forename: Wareef
authors.initials: W
authors.lastname: Kabbani
authors.forename: Xian-Jin
authors.initials: XJ
authors.lastname: Xie
authors.forename: William G
authors.initials: WG
authors.lastname: Bornmann
authors.forename: David A
authors.initials: DA
authors.lastname: Boothman
authors.forename: Jinming
authors.initials: J
authors.lastname: Gao
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D004337:Drug Carriers / Q000008:administration & dosage; D004343:Drug Implants / Q000008:administration & dosage* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009285:Naphthoquinones / Q000008:administration & dosage* / Q000627:therapeutic use; D011108:Polymers / Q000494:pharmacology; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D004337:Drug Carriers; D004343:Drug Implants; D009285:Naphthoquinones; D011108:Polymers; C014638:beta-lapachone