Preclinical Evaluation of Liposomal C8 Ceramide as a Potent anti-Hepatocellular Carcinoma Agent

PLoS One. 2016 Jan 4;11(1):e0145195. doi: 10.1371/journal.pone.0145195. eCollection 2016.

Abstract

Hepatocellular carcinoma (HCC) remains a global health threat. The search for novel anti-HCC agents is urgent. In the current study, we synthesized a liposomal C8 ceramide, and analyzed its anti-tumor activity in pre-clinical HCC models. The liposomal C8 (ceramide) potently inhibited HCC cell (HepG2, SMMC-7721 and Huh-7 lines) survival and proliferation, more efficiently than free C8 ceramide. Yet, non-cancerous HL7702 human hepatocytes were resistant to the liposomal C8 treatment. Liposomal C8 activated caspase-dependent apoptosis in HCC cells, and HCC cytotoxicity by liposomal C8 was significantly attenuated with co-treatment of caspase inhibitors. At the molecular level, we showed that liposomal C8 activated ASK1 (apoptosis signal-regulating kinase 1)-JNK (Jun N-terminal protein kinase) signaling in HCC cells. On the other hand, JNK pharmacological inhibition or dominant negative mutation, as well as ASK1 shRNA-knockdown remarkably inhibited liposomal C8-induced apoptosis in HCC cells. Further studies showed that liposomal C8 inhibited AKT-mTOR (mammalian target of rapamycin) activation in HCC cells. Restoring AKT-mTOR activation by introducing a constitutively-active AKT alleviated HepG2 cytotoxicity by liposomal C8. In vivo, intravenous (i.v.) injection of liposomal C8 significantly inhibited HepG2 xenograft growth in severe combined immuno-deficient (SCID) mice, and mice survival was significantly improved. These preclinical results suggest that liposomal C8 could be further studied as a valuable anti-HCC agent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Carcinoma, Hepatocellular / enzymology
  • Carcinoma, Hepatocellular / pathology*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Drug Screening Assays, Antitumor
  • Enzyme Activation
  • Humans
  • Liposomes*
  • Liver Neoplasms / enzymology
  • Liver Neoplasms / pathology*
  • MAP Kinase Kinase 4 / metabolism
  • MAP Kinase Kinase Kinase 5 / metabolism
  • Male
  • Mice
  • Mice, SCID
  • Sphingosine / analogs & derivatives*
  • Sphingosine / pharmacology

Substances

  • 2,3-N-octanoylsphingosine
  • Liposomes
  • MAP Kinase Kinase Kinase 5
  • MAP3K5 protein, human
  • MAP Kinase Kinase 4
  • Sphingosine

Grants and funding

This study was supported by National science foundation of China (81373990). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.