The Antipancreatic Cancer Activity of OSI-027, a Potent and Selective Inhibitor of mTORC1 and mTORC2

DNA Cell Biol. 2015 Oct;34(10):610-7. doi: 10.1089/dna.2015.2886. Epub 2015 Aug 18.

Abstract

In the present study, we investigated the potential activity of OSI-027, a potent and selective mammalian target of rapamycin (mTOR) complex 1/2 (mTORC1/2) dual inhibitor, against pancreatic cancer cells both in vitro and in vivo. We demonstrated that OSI-027 inhibited survival and growth of both primary and transformed (PANC-1 and MIA PaCa-2 lines) human pancreatic cancer cells. Meanwhile, OSI-027 induced caspase-dependent apoptotic death of the pancreatic cancer cells. On the other hand, caspase inhibitors alleviated cytotoxicity by OSI-027. At the molecular level, OSI-027 treatment blocked mTORC1 and mTORC2 activation simultaneously, without affecting ERK-mitogen-activated protein kinase activation. Importantly, OSI-027 activated cytoprotective autophagy in the above cancer cells. Whereas pharmacological blockage of autophagy or siRNA knockdown of Beclin-1 significantly enhanced the OSI-027-induced activity against pancreatic cancer cells. Specifically, a relatively low dose of OSI-027 sensitized gemcitabine-induced pancreatic cancer cell death in vitro. Further, administration of OSI-027 or together with gemcitabine dramatically inhibited PANC-1 xenograft growth in severe combined immunodeficiency mice, leading to significant mice survival improvement. In summary, the preclinical results of this study suggest that targeting mTORC1/2 synchronously by OSI-027 could be further investigated as a valuable treatment for pancreatic cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology*
  • Antineoplastic Combined Chemotherapy Protocols / pharmacology
  • Apoptosis / drug effects
  • Apoptosis Regulatory Proteins / genetics
  • Apoptosis Regulatory Proteins / metabolism
  • Autophagy / drug effects
  • Beclin-1
  • Cell Line, Tumor / drug effects
  • Cell Survival / drug effects
  • Deoxycytidine / administration & dosage
  • Deoxycytidine / analogs & derivatives
  • Deoxycytidine / pharmacology
  • Gemcitabine
  • Humans
  • Imidazoles / administration & dosage
  • Imidazoles / pharmacology*
  • Mechanistic Target of Rapamycin Complex 1
  • Mechanistic Target of Rapamycin Complex 2
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mice, SCID
  • Multiprotein Complexes / antagonists & inhibitors*
  • Pancreatic Neoplasms / drug therapy*
  • Pancreatic Neoplasms / pathology
  • TOR Serine-Threonine Kinases / antagonists & inhibitors*
  • Triazines / administration & dosage
  • Triazines / pharmacology*
  • Xenograft Model Antitumor Assays

Substances

  • Antineoplastic Agents
  • Apoptosis Regulatory Proteins
  • BECN1 protein, human
  • Beclin-1
  • Imidazoles
  • Membrane Proteins
  • Multiprotein Complexes
  • OSI 027
  • Triazines
  • Deoxycytidine
  • Mechanistic Target of Rapamycin Complex 1
  • Mechanistic Target of Rapamycin Complex 2
  • TOR Serine-Threonine Kinases
  • Gemcitabine