Inhibition of Carcinoma Cell Growth and Metastasis by a Vesicular Stomatitis Virus G-Pseudotyped Retrovector Expressing Type I Insulin-Like Growth Factor Receptor Antisense

A replication-defective, vesicular stomatitis virus G-pseudotyped, Moloney murine leukemia virus retroviral vector (vLTR-IGF-IR^AS) was generated in which a type I insulin-like growth factor receptor(IGF-IR) antisense fragment is expressed in a bicistronic mRNA with an enhanced green fluorescent protein (EGFP) reporter under the control of a potent long terminal repeat (LTR). The suitability of these retroparticles for gene therapy was tested with highly metastatic, carcinoma H-59 cells, which depend on IGF-IR expression for tumorigenicity and metastasis. Transduction with these, but not with control retroviral particles expressing EGFP only, resulted in a 70% reduction in IGF-IR levels and the loss of IGF-IR-regulated functions. Moreover, the ability of vLTR-IGF-IR^AS retroparticle-transduced tumor cells to form experimental hepatic metastases was significantly reduced relative to controls. The results identify retrovector-mediated delivery of IGF-IR antisense as a potential strategy for cancer gene therapy.