title: Impact of intraperitoneal, sustained delivery of paclitaxel on the expression of P-glycoprotein in ovarian tumors.
abstract: Recently, we developed a novel implantable drug delivery system which can provide sustained intraperitoneal (i.p.) delivery of paclitaxel (PTX). As the impact of local sustained delivery on the development of multidrug resistance (MDR) is unknown, the objective of this study was to determine the impact of this drug delivery system on the in vivo expression of MDR1/P-glycoprotein (PGP) in a human ovarian xenograft tumor model. As compared to controls, intermittent i.p. dosing with PTX formulated in Cremophor EL (PTX(CrEL)) induced a two-fold increase in mRNA levels of MDR1 after a 14-day dosing period. On the other hand, sustained i.p. delivery of PTX with the implant system (PTX(film)) did not significantly affect MDR1 expression. Immunodetection of PGP in isolated xenografts supported the mRNA data. Histological analysis by H&E staining demonstrated a dose-dependent increase in tumor necrosis in the PTX(film) treated animals. Further, in vitro studies in human ovarian carcinoma cells also demonstrated a significant induction in the efflux activity of PGP with intermittent dosing schedules to PTX(CrEL) whereas this was not seen in cells dosed with PTX(film). Our findings suggest that sustained i.p. administration with PTX(film) attenuates development of MDR, suggesting that sustained, localized delivery of chemotherapeutic agents may improve current treatment strategies for ovarian cancer.
authors.affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College St, Toronto, Ontario, Canada M5S 3M2.
authors.forename: Emmanuel A
authors.initials: EA
authors.lastname: Ho
authors.forename: Patrick Lim
authors.initials: PL
authors.lastname: Soo
authors.forename: Christine
authors.initials: C
authors.lastname: Allen
authors.forename: Micheline
authors.initials: M
authors.lastname: Piquette-Miller
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis*; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage* / Q000378:metabolism / Q000494:pharmacology*; D045744:Cell Line, Tumor; D003692:Delayed-Action Preparations; D004305:Dose-Response Relationship, Drug; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007274:Injections, Intraperitoneal; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010051:Ovarian Neoplasms / Q000378:metabolism*; D017239:Paclitaxel / Q000008:administration & dosage* / Q000378:metabolism / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000972:Antineoplastic Agents, Phytogenic; D003692:Delayed-Action Preparations; D012333:RNA, Messenger; D017239:Paclitaxel