title: Docetaxel loaded oleic acid-coated hydroxyapatite nanoparticles enhance the docetaxel-induced apoptosis through activation of caspase-2 in androgen independent prostate cancer cells.
abstract: Docetaxel (Dtxl) remains the preferred choice of improving the survival of patients with hormone refractory prostate cancer (HRPC), but many patients suffer from modest drug response and significant toxicity. In the present study, we investigated the efficiency of novel Dtxl loaded-[1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-carboxy(polyethylene glycol)]2000 (DSPE-PEG-COOH) stabilized-oleic acid (OA) coated hydroxyapatite (HA) nanoparticles (Dtxl-NPs) and gained insights into the molecular mechanism of the apoptosis induced by these novel Dtxl-loaded nanoparticles. The drug encapsulation efficiency of Dtxl was 83.6% and the sustained drug release was observed over 30days. The Dtxl-NPs exhibited significantly more cytotoxicity in both prostate cancer cell lines (PC3 and DU145) compared with Dtxl in vitro and increased the Dtxl-induced apoptosis in the PC3 cells. Cell cycle analysis showed that the PC3 cells treated with Dtxl-NPs exhibited significant arrest in the G2-M phase but a higher sub-G(0)/G(1) population when compared with Dtxl. The enhanced apoptosis induced by Dtxl-NPs in the PC3 cells was associated with the changes in mitochondrial membrane potential (MMP) and seemed to involve the activation of caspase-2. The kinetic studies of caspases demonstrated an early activation of caspase-2 in Dtxl-NPs-induced apoptosis in PC3 cells, which differs from Dtxl-induced apoptosis. The inhibition of caspase-2 activation by small interfering RNA (siRNA) knockdown resulted in the significant inhibition of Dtxl-NPs-induced disruption of MMP and Dtxl-NPs-induced apoptosis, indicating that the activation of caspase-2 was the critical event before the mitochondrial depolarization in the PC3 cells. Our findings showed that nanoparticles, more than simple drug carriers, may play an active role in mediating the biological effects.
authors.affiliation: Department of Urology, Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Luo
authors.forename: You
authors.initials: Y
authors.lastname: Ling
authors.forename: Wusheng
authors.initials: W
authors.lastname: Guo
authors.forename: Jun
authors.initials: J
authors.lastname: Pang
authors.forename: Weipeng
authors.initials: W
authors.lastname: Liu
authors.forename: Youqiang
authors.initials: Y
authors.lastname: Fang
authors.forename: Xinqiao
authors.initials: X
authors.lastname: Wen
authors.forename: Kun
authors.initials: K
authors.lastname: Wei
authors.forename: Xin
authors.initials: X
authors.lastname: Gao
mesh_terms: D000728:Androgens / Q000378:metabolism; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053143:Caspase 2 / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D000077143:Docetaxel; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding; D017886:Durapatite / Q000737:chemistry*; D004789:Enzyme Activation; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D053758:Nanoparticles / Q000737:chemistry*; D019301:Oleic Acid / Q000737:chemistry*; D010316:Particle Size; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D034741:RNA, Small Interfering / Q000494:pharmacology; D043823:Taxoids / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology
chemical_list: D000728:Androgens; D000970:Antineoplastic Agents; D004337:Drug Carriers; D034741:RNA, Small Interfering; D043823:Taxoids; D000077143:Docetaxel; D019301:Oleic Acid; D017886:Durapatite; C490360:CASP2 protein, human; D053143:Caspase 2; D003546:Cysteine Endopeptidases