Gene transfer is an attractive approach to fight cancer by targeting cancer cells or their vasculature. Our study reports the inhibition of tumor growth and angiogenesis by a nonviral method using dendrimers associated with 36-mer anionic oligomers (ON36) for delivering angiostatin (Kringle 1-3) and tissue inhibitor of metalloproteinase (TIMP)-2 genes. The optimal concentrations of dendrimers and ON36 for an efficient green fluorescent protein (GFP) plasmid delivery in endothelial cells (HMEC-1) and cancer cells (MDA-MB-435) were first chosen. Then the efficacy of transfection was determined by testing angiostatin and TIMP-2 secretion by Western blot and the biologic effects were evaluated. Angiostatin gene transfer markedly reduced in vitro (i) HMEC-1 but not MDA-MB-435 proliferation; (ii) HMEC-1 and MDA-MB-435 wound healing reparation; and (iii) capillary tube formation. TIMP-2 gene transfer did not affect cell proliferation but strongly inhibited (i) wound healing of HMEC-1 and MDA-MB-435 cells; and (ii) capillary tube formation. Supernatants of transfected-MDA-MB-435 cells also inhibited the formation of angiogenic networks on Matrigel, indicating a paracrine effect. In vivo, intratumoral angiostatin or TIMP-2 gene delivery using dendrimers associated with ON36 effectively inhibited tumor growth by 71% and 84%, respectively. Combined gene transfer resulted in 96% inhibition of tumor growth. Tumor-associated vascularization was also greatly reduced. These findings provide a basis for the further development of nonviral delivery of genes to fight cancer.
Copyright 2003 Wiley-Liss, Inc.