title: A polymer library approach to suicide gene therapy for cancer.
abstract: Optimal gene therapy for cancer must (i) deliver DNA to tumor cells with high efficiency, (ii) induce minimal toxicity, and (iii) avoid gene expression in healthy tissues. To this end, we generated a library of >500 degradable, poly(beta-amino esters) for potential use as nonviral DNA vectors. Using high-throughput methods, we screened this library in vitro for transfection efficiency and cytotoxicity. We tested the best performing polymer, C32, in mice for toxicity and DNA delivery after intratumor and i.m. injection. C32 delivered DNA intratumorally approximately 4-fold better than one of the best commercially available reagents, jetPEI (polyethyleneimine), and 26-fold better than naked DNA. Conversely, the highest transfection levels after i.m. administration were achieved with naked DNA, followed by polyethyleneimine; transfection was rarely observed with C32. Additionally, polyethyleneimine induced significant local toxicity after i.m. injection, whereas C32 demonstrated no toxicity. Finally, we used C32 to deliver a DNA construct encoding the A chain of diphtheria toxin (DT-A) to xenografts derived from LNCaP human prostate cancer cells. This construct regulates toxin expression both at the transcriptional level by the use of a chimeric-modified enhancer/promoter sequence of the human prostate-specific antigen gene and by DNA recombination mediated by Flp recombinase. C32 delivery of the A chain of diphtheria toxin DNA to LNCaP xenografts suppressed tumor growth and even caused 40% of tumors to regress in size. Because C32 transfects tumors locally at high levels, transfects healthy muscle poorly, and displays no toxicity, it may provide a vehicle for the local treatment of cancer.
authors.affiliation: Department of Chemical Engineering and Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Anderson
authors.forename: Weidan
authors.initials: W
authors.lastname: Peng
authors.forename: Akin
authors.initials: A
authors.lastname: Akinc
authors.forename: Naushad
authors.initials: N
authors.lastname: Hossain
authors.forename: Anat
authors.initials: A
authors.lastname: Kohn
authors.forename: Robert
authors.initials: R
authors.lastname: Padera
authors.forename: Robert
authors.initials: R
authors.lastname: Langer
authors.forename: Janet A
authors.initials: JA
authors.lastname: Sawicki
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D045744:Cell Line, Tumor; D004274:DNA, Recombinant / Q000008:administration & dosage / Q000235:genetics; D004167:Diphtheria Toxin / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D008297:Male; D008422:Materials Testing; D051379:Mice; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000096:biosynthesis; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D010446:Peptide Fragments / Q000235:genetics; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D014162:Transfection; D014183:Transplantation, Heterologous
chemical_list: D001672:Biocompatible Materials; D004274:DNA, Recombinant; D004167:Diphtheria Toxin; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D011108:Polymers; C029795:diphtheria toxin fragment A