Endothelial progenitor cells as cellular vehicles to deliver oncolytic virus therapies to metastatic tumors: the "Trojan horse" approach.

In view of the limited success of available treatment modalities for metastatic tumor, alternative and complementary strategies need to be developed. Oncolytic viruses are capable of selective replication in malignant cells and therefore offer levels of potency and specificity that are potentially far higher than conventional treatments for tumor. However, lack of systemic delivery technique for therapeutic viruses impacts their application in treating patients with multiple disseminated metastases. Recent studies have demonstrated that when being transplanted, endothelial progenitor cells can migrate via peripheral blood and home exclusively to the site of tumor neovasculature. We hypothesized that endothelial progenitor cells can act as "Trojan horse" to systemically deliver oncolytic virus to metastases in order to inhibit tumor neovascularization formation and eventually eradicate the metastatic tumor.