Enhanced Potency of GalNAc-Conjugated Antisense Oligonucleotides in Hepatocellular Cancer Models

Antisense oligonucleotides (ASOs) are a novel therapeutic approach to target difficult-to-drug protein classes by targeting their corresponding mRNAs. Significantly enhanced ASO activity has been achieved by the targeted delivery of ASOs to selected tissues. One example is the targeted delivery of ASOs to hepatocytes, achieved with N-acetylgalactosamine (GalNAc) conjugation to ASO, which results in selective uptake by asialoglycoprotein receptor (ASGR). Here we have evaluated the potential of GalNAc-conjugated ASOs as a therapeutic approach to targeting difficult-to-drug pathways in hepatocellular carcinoma (HCC). The activity of GalNAc-conjugated ASOs was superior to that of the unconjugated parental ASO in ASGR (+) human HCC cells in vitro, but not in ASGR (-) cells. Both humanand mouse-derived HCC displayed reduced levels of ASGR, however, despite this, GalNAc-conjugated ASOs showed a 5to 10-fold increase in potency in tumors. Systemically administered GalNAc-conjugated ASOs demonstrated both enhanced antisense activity and antitumor activity in the diethylnitros-amine- induced HCC tumor model. Finally, GalNAc conjugation enhanced ASO activity in human circulating tumor cells from HCC patients, demonstrating the potential of this approach in primary human HCC tumor cells. Taken together, these results provide a strong rationale for a potential therapeutic use of GalNAc-conjugated ASOs for the treatment of HCC.