ABSTRACT
Many members of the enterovirus family are considered as promising oncolytic agents; however, their systemic administration is largely inefficient due to the rapid neutralization of the virus in the circulation and the barrier functions of the endothelium. We aimed to evaluate natural killer cells as carriers for the delivery of oncolytic enteroviruses, which would combine the effects of cell immunotherapy with virotherapy. We tested four strains of nonpathogenic enteroviruses against the glioblastoma cell line panel and evaluated the produced infectious titers. Next, we explored whether these virus strains could be delivered to the tumor by natural killer cell line NK-92, which is being actively evaluated as a clinically acceptable therapeutic. Several strains of enteroviruses demonstrated oncolytic properties, but only coxsackievirus A7 (CVA7) could replicate in NK-92 cells efficiently. We compared the delivery efficiency of CVA7 in vivo, using NK-92 cells and direct intravenous administration, and found significant advantages of cell delivery even after a single injection. This suggests that the NK-92 cell line can be utilized as a vehicle for the delivery of the oncolytic strain of CVA7, which would improve the clinical potential of this viral oncolytic for the treatment of glioblastoma multiforme and other forms of cancer.
ABSTRACT
RIL/PDLIM4 gene was identified as a tumor suppressor, its expression is frequently altered in various types of malignancies. The product of RIL/PDLIM4 gene is an adapter protein involved in the actin cytoskeleton remolding and assembly of stress fibers crucial for cell motility and epithelial-mesenchymal transition. Although the exact mechanism tethering RIL to cancer development remains unknown some pieces of evidence suggest that RIL may act by suppressing activation of the proto-oncogene tyrosine-protein kinase Src. To further explore this issue we tested how different expression levels of RIL affected the activity of Src in breast cancer cell lines. RIL was ectopically overexpressed in the cell cultures with its relatively low endogenous level, or, otherwise, was downregulated by RNA interference. Whereas we observed no correlation between expression levels of RIL and activity of Src we found that in several cell lines elevated levels of RIL were associated with higher cell migratory activity along with the increased incidence of breast xenograft formation and metastasizing. The obtained data suggest that in some breast cancer models RIL may not act as Src kinase inhibitor, but rather play the role of a potential oncogene that promotes cell motility and contributes to cancer cells spreading.
