Composite fatty acid ether amides suppress growth of liver cancer cells in vitro and in an in vivo allograft mouse model

The heterogeneity of liver cancer, in particular hepatocellular carcinoma (HCC), portrays the requirement of multiple targets for both its treatment and prevention. Multifaceted agents, minimally or non-toxic for normal hepatocytes, are required to address the molecular diversity of HCC, including the resistance of putative liver cancer stem cells to chemotherapy.

We designed and synthesized two fatty acid ethers of isopropylamino propanol, C16:0-AIP-1 and C18:1-AIP-2 (jointly named AIPs), and evaluated their anti-proliferative effects on the human HCC cell line Huh7 and the murine hepatoma cell line BNL 1MEA.7R.1, both in vitro and in an in vivo allograft mouse model.

We found that AIP-1 and AIP-2 inhibited proliferation and caused cell death in both Huh7 and BNL 1MEA.7R.1 cells. Importantly, AIP-1 and AIP-2 were found to block the activation of putative liver cancer stem cells as manifested by suppression of clonal ‘carcinosphere’ development in growth factor-free and anchorage-free medium. The AIPs exhibited a relatively low toxicity against normal human or rat hepatocytes in primary cultures. In addition, we found that the AIPs utilized multifaceted pathways that mediate both autophagy and apoptosis in HCC, including the inhibition of AKTs and CAMK-1. In immune-competent mice, the AIPs significantly reduced BNL 1MEA.7R.1 cell-driven tumor allograft development, with a higher efficiency than sorafenib. A combination of AIP-1 + AIP-2 was most effective in reducing the tumor allograft incidence.

AIPs represent a novel class of simple fatty acid derivatives that are effective against liver tumors via diverse pathways. They show a low toxicity towards normal hepatocytes. The addition of AIPs may represent a new avenue towards the management of chronic liver injury and, ultimately, the prevention and treatment of HCC.