A Novel Oncolytic Herpes Capable of Cell-Specific Transcriptional Targeting of CD133± Cancer Cells Induces Significant Tumor Regression.

The topic of cancer stem cells (CSCs) is of significant importance due to its implications in our understanding of the tumor biology as well as the development of novel cancer therapeutics. However, the question of whether targeting CSCs can hamper the growth of tumors remains mainly unanswered due to the lack of specific agents for this purpose. To address this issue, we have developed the first mutated version of herpes simplex virus-1 that is transcriptionally targeted against CD133+ cells. CD133 has been portrayed as one of the most important markers in CSCs involved in the biology of a number of human cancers, including liver, brain, colon, skin, and pancreas. The virus developed in this work, Signal-Smart 2, showed specificity against CD133+ cells in three different models (hepatocellular carcinoma, colorectal cancer, and melanoma) resulting in a loss of viability and invasiveness of cancer cells. Additionally, the virus showed robust inhibitory activity against in vivo tumor growth in both preventive and therapeutic mouse models as well as orthotopic model highly relevant to potential clinical application of this virus. Therefore, we conclude that targeting CD133+ CSCs has the potential to be pursued as a novel strategy against cancer. Stem Cells 2018;36:1154-1169.