Combinatorial therapies improve the therapeutic efficacy of nanoliposomal ceramide for pancreatic cancer

Cancer Biol Ther. 2011 Oct 1;12(7):574-85. doi: 10.4161/cbt.12.7.15971. Epub 2011 Oct 1.

Abstract

Poor prognosis cancers, such as pancreatic cancer, represent inherent challenges for ceramide-based nanotherapeutics due to metabolic pathways, which neutralize ceramide to less toxic or pro-oncogenic metabolites. We have recently developed a novel 80 nanometer diameter liposomal formulation that incorporates 30 molar percent C6-ceramide, a bioactive lipid that is pro-apoptotic to many cancer cells, but not to normal cells. In this manuscript, we evaluated the efficacy of combining nanoliposomal C6-ceramide (Lip-C6) with either gemcitabine or an inhibitor of glucosylceramide synthase. We first assessed the biological effect of Lip-C6 in PANC-1 cells, a gemcitabine-resistant human pancreatic cancer cell line, and found that low doses alone did not induce cell toxicity. However, cytotoxicity was achieved by combining Lip-C6 with either non-toxic sub-therapeutic concentrations of gemcitabine or with the glucosylceramide synthase inhibitor D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP). Furthermore, these combinations with Lip-C6 cooperatively inhibited PANC-1 tumor growth in vivo. Mechanistically, Lip-C6 inhibited pro-survival Akt and Erk signaling, whereas the nucleoside analog gemcitabine did not. Furthermore, by including PDMP within the nanoliposomes, which halted ceramide neutralization as evidenced by LC-MS3, the cytotoxic effects of Lip-C6 were enhanced. Collectively, we have demonstrated that nanoliposomal ceramide can be an effective anti-pancreatic cancer therapeutic in combination with gemcitabine or an inhibitor of ceramide neutralization.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Combined Chemotherapy Protocols / administration & dosage
  • Antineoplastic Combined Chemotherapy Protocols / pharmacology*
  • Cell Line, Tumor
  • Ceramides / administration & dosage
  • Ceramides / pharmacokinetics
  • Ceramides / pharmacology*
  • Deoxycytidine / administration & dosage
  • Deoxycytidine / analogs & derivatives*
  • Deoxycytidine / pharmacology
  • Deoxycytidine / therapeutic use
  • Drug Carriers / therapeutic use
  • Drug Resistance, Neoplasm
  • Drug Synergism
  • Enzyme Inhibitors / pharmacology
  • Female
  • Gemcitabine
  • Glucosyltransferases / antagonists & inhibitors
  • Humans
  • Liposomes / therapeutic use
  • MAP Kinase Signaling System / drug effects
  • Mice
  • Mice, Nude
  • Morpholines / administration & dosage
  • Morpholines / pharmacology
  • Nanoparticles / administration & dosage
  • Nanoparticles / therapeutic use
  • Pancreatic Neoplasms / drug therapy*
  • Proto-Oncogene Proteins c-akt / antagonists & inhibitors
  • Proto-Oncogene Proteins c-akt / metabolism
  • Xenograft Model Antitumor Assays

Substances

  • Ceramides
  • Drug Carriers
  • Enzyme Inhibitors
  • Liposomes
  • Morpholines
  • Deoxycytidine
  • RV 538
  • Glucosyltransferases
  • ceramide glucosyltransferase
  • Proto-Oncogene Proteins c-akt
  • N-(alpha-hydroxyoctadecanoyl)phytosphingosine
  • Gemcitabine