title: Modulation of drug resistance in ovarian adenocarcinoma by enhancing intracellular ceramide using tamoxifen-loaded biodegradable polymeric nanoparticles.
abstract: OBJECTIVE
  To modulate intracellular ceramide levels and lower the apoptotic threshold in multidrug-resistant ovarian adenocarcinoma, we have examined the efficacy and preliminary safety of tamoxifen coadministration with paclitaxel in biodegradable poly(ethylene oxide)-modified poly(epsilon-caprolactone) (PEO-PCL) nanoparticles.
  
  
  METHODS
  In vitro cytotoxicity and proapoptotic activity of paclitaxel and tamoxifen, either as single agent or in combination, was examined in wild-type (SKOV3) and MDR-1-positive (SKOV3TR) human ovarian adenocarcinoma cells. Subcutaneous SKOV3 and SKOV3TR xenografts were established in female nu/nu mice, and this model was used to evaluate the antitumor efficacy and preliminary safety. Paclitaxel (20 mg/kg) and tamoxifen (70 mg/kg) were administered i.v. either as a single agent or in combination in aqueous solution and in PEO-PCL nanoparticles.
  
  
  RESULTS
  In vitro cytotoxicity results showed that administration of paclitaxel and tamoxifen in combination lowered the IC50 of paclitaxel by 10-fold in SKOV3 cells and by >3-fold in SKOV3TR cells. The combination paclitaxel/tamoxifen co-therapy showed even more pronounced effect when administered in nanoparticle formulations. Upon i.v. administration of paclitaxel/tamoxifen combination in PEO-PCL nanoparticle formulations, significant enhancement in antitumor efficacy was observed. Furthermore, the combination paclitaxel/tamoxifen therapy did not induce any acute toxicity as measured by body weight changes, blood cell counts, and hepatotoxicity.
  
  
  CONCLUSIONS
  The results of this study show that combination of paclitaxel and tamoxifen in biodegradable PEO-PCL nanoparticles can serve as an effective clinically translatable strategy to overcome multidrug resistance in ovarian cancer.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, Northeastern University, Boston, MA 02115, USA.
authors.forename: Harikrishna
authors.initials: H
authors.lastname: Devalapally
authors.forename: Zhenfeng
authors.initials: Z
authors.lastname: Duan
authors.forename: Michael V
authors.initials: MV
authors.lastname: Seiden
authors.forename: Mansoor M
authors.initials: MM
authors.lastname: Amiji
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000378:metabolism; D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage*; D045744:Cell Line, Tumor; D002518:Ceramides / Q000378:metabolism*; D003593:Cytoplasm / Q000737:chemistry / Q000187:drug effects; D016503:Drug Delivery Systems / Q000379:methods*; D018432:Drug Resistance, Multiple / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D005260:Female; D006801:Humans; D020287:In Situ Nick-End Labeling; D051379:Mice; D008819:Mice, Nude; D053758:Nanoparticles; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D017239:Paclitaxel / Q000008:administration & dosage; D011091:Polyesters; D011092:Polyethylene Glycols; D020845:Selective Estrogen Receptor Modulators / Q000008:administration & dosage; D013629:Tamoxifen / Q000008:administration & dosage
chemical_list: D002518:Ceramides; D011091:Polyesters; D020845:Selective Estrogen Receptor Modulators; D013629:Tamoxifen; C016240:polycaprolactone; D011092:Polyethylene Glycols; D017239:Paclitaxel