Novel strategy of liver cancer treatment with modified antisense oligonucleotides targeting human vasohibin‐2

Vasohihibin‐2 (VASH2) is a homolog of vasohibin‐1 (VASH1) and is overexpressed in various cancers. Vasohihibin‐2 acts on both cancer cells and cancer microenvironmental cells. Previous analyses have shown that VASH2 promotes cancer progression and abrogation of VASH2 results in significant anticancer effects. We therefore propose VASH2 to be a practical molecular target for cancer treatment. Modifications of antisense oligonucleotide (ASO) such as bridged nucleic acids (BNA)‐based modification increases the specificity and stability of ASO, and are now applied to the development of a number of oligonucleotide‐based drugs. Here we designed human VASH2‐ASOs, selected an optimal one, and developed 2′,4′‐BNA‐based VASH2‐ASO. When systemically administered, naked 2′,4′‐BNA‐based VASH2‐ASO accumulated in the liver and showed its gene‐silencing activity. We then examined the effect of 2′,4′‐BNA‐based VASH2‐ASO in liver cancers. Intraperitoneal injection of naked 2′,4′‐BNA‐based VASH2‐ASO exerted a potent antitumor effect on orthotopically inoculated human hepatocellular carcinoma cells. The same manipulation also showed potent antitumor activity on the splenic inoculation of human colon cancer cells for liver metastasis. These results provide a novel strategy for the treatment of primary as well as metastatic liver cancers by using modified ASOs targeting VASH2.