RT Journal Article SR Electronic T1 Nanoparticle Targeting of Anticancer Drug Improves Therapeutic Response in Animal Model of Human Epithelial Cancer JF Cancer Research JO Cancer Res FD American Association for Cancer Research SP 5317 OP 5324 DO 10.1158/0008-5472.CAN-04-3921 VO 65 IS 12 A1 Kukowska-Latallo, Jolanta F. A1 Candido, Kimberly A. A1 Cao, Zhengyi A1 Nigavekar, Shraddha S. A1 Majoros, Istvan J. A1 Thomas, Thommey P. A1 Balogh, Lajos P. A1 Khan, Mohamed K. A1 Baker, James R. YR 2005 UL http://cancerres.aacrjournals.org/content/65/12/5317.abstract AB Prior studies suggested that nanoparticle drug delivery might improve the therapeutic response to anticancer drugs and allow the simultaneous monitoring of drug uptake by tumors. We employed modified PAMAM dendritic polymers <5 nm in diameter as carriers. Acetylated dendrimers were conjugated to folic acid as a targeting agent and then coupled to either methotrexate or tritium and either fluorescein or 6-carboxytetramethylrhodamine. These conjugates were injected i.v. into immunodeficient mice bearing human KB tumors that overexpress the folic acid receptor. In contrast to nontargeted polymer, folate-conjugated nanoparticles concentrated in the tumor and liver tissue over 4 days after administration. The tumor tissue localization of the folate-targeted polymer could be attenuated by prior i.v. injection of free folic acid. Confocal microscopy confirmed the internalization of the drug conjugates into the tumor cells. Targeting methotrexate increased its antitumor activity and markedly decreased its toxicity, allowing therapeutic responses not possible with a free drug.