214. Specific Targeting of IL-13 Receptor alpha 2 Expressing Breast Cancer Cells by Paramyxovirus-Pseudotyped Lentiviral Vectors Displaying IL-13

Abstract

The ability to selectively target specific cell types is highly desirable for the in vivo application of viral vectors for the treatment of multiple diseases including cancer. Lentiviral vectors (LV) have the advantage of being easily pseudotyped allowing their tropism to be altered. LV can also be engineered to deliver therapeutic or cytotoxic genes directly to cancer cells. IL-13 receptor alpha 2 (IL-13Rα2) is overexpressed in many different tumor types, including glioma, sarcoma, kidney, breast and ovarian cancer, making it an attractive target for tumor therapy. We have previously shown that firefly luciferase-expressing LV pseudotyped with a truncated fusion (F) protein derived from measles virus (MV) and a tail-truncated, receptor-blind MV hemagglutinin (H) protein bearing IL-13 at the C-terminus were capable of transducing IL-13Rα2-positive U251 glioma cells when administered intratumorally. In addition, we have shown the ability of LV to be pseudotyped using the F and H proteins from the Tupaia paramyxovirus (TPMV). TPMV does not infect human cells, potentially making it a safer choice for pseudotyping LV for in vivo delivery. Similar to the MV H protein, the TPMV H protein can also display IL-13 and bind specifically to IL-13Rα2-positive tumor cells. We plan to confirm and extend these findings by examining the targeting of LV-MV-IL-13 and LV-TPMV-IL-13 in metastatic orthotopic models of breast cancer by intratumoral and intravenous administration. In addition, LV expressing HSV1 thymidine kinase (TK) were constructed and are being evaluated for antitumor efficacy.