Antitumor activity of cytotoxic T lymphocytes engineered to target vascular endothelial growth factor receptors

Abstract

The demonstration that angiogenesis is required for the growth of solid tumors has fueled an intense interest in the development of new therapeutic strategies that target the tumor vasculature. Here we report the development of an immune-based antiangiogenic strategy that is based on the generation of T lymphocytes that possess a killing specificity for cells expressing vascular endothelial growth factor receptors (VEGFRs). To target VEGFR-expressing cells, recombinant retroviral vectors were generated that encoded a chimeric T cell receptor comprised of VEGF sequences linked to intracellular signaling sequences derived from the chain of the T cell receptor. After transduction of primary murine CD8 lymphocytes by such vectors, the transduced cells were shown to possess an efficient killing specificity for cells expressing the VEGF receptor, Flk-1, as measured by in vitro cytotoxicity assays. After adoptive transfer into tumor-bearing mice, the genetically modified cytotoxic T lymphocytes strongly inhibited the growth of a variety of syngeneic murine tumors and human tumor xenografts. An increased effect on in vivo tumor growth inhibition was seen when this therapy was combined with the systemic administration of TNP-470, a conventional angiogenesis inhibitor. The utilization of the immune system to target angiogenic markers expressed on tumor vasculature may prove to be a powerful means for controlling tumor growth.

Gene therapy using genetically modified lymphocytes targeting VEGFR-2 inhibits the growth of vascularized syngenic tumors in mice

“…Despite its demonstrated effectiveness in experimental mouse tumor models and in humans, the clinical application of ACT is limited because of the need to identify antigens with highly selective expression in cancer, escape of tumor cells from immune destruction by antigen modulation, decreased MHC expression by tumor cells, lack of costimulatory molecule expression on tumors, and other immunosuppressive mechanisms at the tumor site that impede extravasation and survival of T cells and dampening immune responses (46)(47)(48)(49)(50). Antiangiogenic approaches can potentially overcome many of these tumor-specific factors, though the cytostatic nature of the available treatments and the redundancy of angiogenic pathways have limited its effectiveness (10,51). Redirecting immune cells to target tumor vasculature offers an alternative to overcome the obstacles confronting both conventional tumor-specific immunotherapy and the use of cytostatic antiangiogenic inhibitors, because of the potent effector functions of activated lymphocytes and the consistent expression of VEGFR-2 on tumor vasculature.…”

Perlecan and Tumor Angiogenesis

“…Overexpression of VEGF stimulates angiogenesis in human ovarian cancer xenografts (Duyndam et al 2002) and enhances tumorigenicity of U251 MG glioma cells in vivo (Ke et al 2002). Inhibition of tumor growth and angiogenesis in animal models has been demonstrated by neutralizing anti-VEGF antibody (Borgstrom et al 1998), reduction of VEGF expression by antisense cDNA (Im et al 1999;Luo et al 2001) or antisense oligonucleotides (Shi and Siemann 2002), soluble Flt-1 (Goldman et al 1998;Hoshida et al 2002), dominant negative Flk-1 (Millauer et al 1994), anti-KDR antibody (Sweeney et al 2002), Flk-1/KDR kinase inhibitor SU5416 (Fong TA et al 1999;Takamoto et al 2001), anti-VEGF 189 or anti-Flk-1 or Flt-1 ribozymes (Oshika et al 2000;Pavco et al 2000), and cytotoxic T-lymphocytes engineered to target Flk-1 (Niederman et al 2002). A synthetic peptide that blocks VEGF-KDR interaction or derives from the second Ig-like domain of Flt-1 can abolish angiogenesis in rabbit corneal and chick chorioallantoic membrane angiogenesis models, respectively (Binetruy-Tournaire et al 2000;Tan et al 2001).…”

The Natural Progression of Microvasculature in Primary Tumor and Lymph Node Metastases in a Breast Carcinoma Model: Relationship between Microvessel Density, Vascular Endothelial Growth Factor Expression and Metastatic Invasion

“…3,4,6 VEGF-C and VEGF-D are important in lymphangiogenesis and lymphatic metastasis. [7][8][9] Blocking VEGF ligand-receptor interactions significantly inhibits tumor growth [10][11][12][13][14][15][16] thus providing a promising target for therapeutic intervention. [17][18][19] Hypoxia is an important regulator of VEGF.…”