Abstract
Cisplatin is used to treat a variety of tumors, but dose limiting toxicities or intrinsic and acquired resistance limit its application in many types of cancer including prostate. We report a unique strategy to deliver cisplatin to prostate cancer cells by constructing Pt(IV)-encapsulated prostate-specific membrane antigen (PSMA) targeted nanoparticles (NPs) of poly(D,L-lactic-co-glycolic acid) (PLGA)-poly(ethylene glycol) (PEG)-functionalized controlled release polymers. By using PLGA-b-PEG nanoparticles with PSMA targeting aptamers (Apt) on the surface as a vehicle for the platinum(IV) compound c,t,c-[Pt(NH3)2(O 2CCH2CH2CH2CH2CH 3)2Cl2] (1), a lethal dose of cisplatin was delivered specifically to prostate cancer cells. PSMA aptamer targeted delivery of Pt(IV) cargos to PSMA+ LNCaP prostate cancer cells by endocytosis of the nanoparticle vehicles was demonstrated using fluorescence microscopy by colocalization of green fluorescent labeled cholesterol-encapsulated NPs and early endosome marker EEA-1. The choice of linear hexyl chains in 1 was the result of a systematic study to optimize encapsulation and controlled release from the polymer without compromising either feature. Release of cisplatin from the polymeric nanoparticles after reduction of 1 and formation of cisplatin 1,2-intrastrand d(GpG) cross-links on nuclear DNA was confirmed by using a monoclonal antibody for the adduct. A comparison between the cytotoxic activities of Pt(IV)-encapsulated PLGA-b-PEG NPs with the PSMA aptamer on the surface (Pt-NP-Apt), cisplatin, and the nontargeted Pt(IV)-encapsulated NPs (Pt-NP) against human prostate PSMA-overexpressing LNCaP and PSMA-PC3 cancer cells revealed significant differences. The effectiveness of PSMA targeted Pt-NP-Apt nanoparticles against the PSMA+ LNCaP cells is approximately an order of magnitude greater than that of free cisplatin.
Original language | English (US) |
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Pages (from-to) | 17356-17361 |
Number of pages | 6 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 105 |
Issue number | 45 |
DOIs | |
State | Published - Nov 11 2008 |
Externally published | Yes |
Keywords
- Controlled release
- DNA cross-link
- Metals in medicine
- PSMA
ASJC Scopus subject areas
- General