Combined targeting of AKT and mTOR using MK-2206 and RAD001 is synergistic in the treatment of cholangiocarcinoma
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Combined targeting of AKT and mTOR using MK-2206 and RAD001 is synergistic in the treatment of cholangiocarcinoma. / Ewald, Florian; Grabinski, Nicole; Grottke, Astrid; Windhorst, Sabine; Nörz, Dominik; Carstensen, Lisa; Staufer, Katharina; Hofmann, Bianca T; Diehl, Frank; David, Kerstin; Schumacher, Udo; Nashan, Björn; Jücker, Manfred.
In: INT J CANCER, Vol. 133, No. 9, 01.11.2013, p. 2065-76.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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TY - JOUR
T1 - Combined targeting of AKT and mTOR using MK-2206 and RAD001 is synergistic in the treatment of cholangiocarcinoma
AU - Ewald, Florian
AU - Grabinski, Nicole
AU - Grottke, Astrid
AU - Windhorst, Sabine
AU - Nörz, Dominik
AU - Carstensen, Lisa
AU - Staufer, Katharina
AU - Hofmann, Bianca T
AU - Diehl, Frank
AU - David, Kerstin
AU - Schumacher, Udo
AU - Nashan, Björn
AU - Jücker, Manfred
N1 - Copyright © 2013 UICC.
PY - 2013/11/1
Y1 - 2013/11/1
N2 - Cholangiocarcinoma (CCA) is a rare, but devastating disease arising from the epithelium of intrahepatic and extrahepatic bile ducts. There are neither effective systemic therapies nor satisfying treatment options for inoperable CCA. Histopathological and biochemical studies of CCA show frequent dysregulation of the phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (mTOR) pathway. Therefore, we investigated the efficacy of the mTOR inhibitor RAD001 and the impact of AKT signaling following mTOR inhibition in the treatment of CCA. RAD001 significantly inhibits proliferation of CCA cell lines, however, a concentration-dependent and isoform specific feedback activation of the three AKT isoforms (AKT1, AKT2 and AKT3) was observed after mTOR inhibition. As activation of AKT might limit the RAD001-mediated anti-tumor effect, the efficacy of combined mTOR and AKT inhibition was investigated using the allosteric AKT inhibitor MK-2206. Our results show that inhibition of AKT potentiates the efficacy of mTOR inhibition both in vitro and in a xenograft mouse model in vivo. Mechanistically, the antiproliferative effect of the pan-AKT inhibitor MK2206 in the CCA cell line TFK-1 was due to inhibition of AKT1 and AKT2, because knockdown of either AKT1 or AKT2, but not AKT3, showed a synergistic reduction of cell proliferation in combination with mTOR treatment. Finally, using an AKT isoform specific in vitro kinase assay, enzymatic activity of each of the three AKT isoforms was detected in all tissue samples from CCA patients, analyzed. In summary, our preclinical data suggest that combined targeting of mTOR and AKT using RAD001 and MK-2206 might be a new, effective strategy for the treatment of CCA.
AB - Cholangiocarcinoma (CCA) is a rare, but devastating disease arising from the epithelium of intrahepatic and extrahepatic bile ducts. There are neither effective systemic therapies nor satisfying treatment options for inoperable CCA. Histopathological and biochemical studies of CCA show frequent dysregulation of the phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (mTOR) pathway. Therefore, we investigated the efficacy of the mTOR inhibitor RAD001 and the impact of AKT signaling following mTOR inhibition in the treatment of CCA. RAD001 significantly inhibits proliferation of CCA cell lines, however, a concentration-dependent and isoform specific feedback activation of the three AKT isoforms (AKT1, AKT2 and AKT3) was observed after mTOR inhibition. As activation of AKT might limit the RAD001-mediated anti-tumor effect, the efficacy of combined mTOR and AKT inhibition was investigated using the allosteric AKT inhibitor MK-2206. Our results show that inhibition of AKT potentiates the efficacy of mTOR inhibition both in vitro and in a xenograft mouse model in vivo. Mechanistically, the antiproliferative effect of the pan-AKT inhibitor MK2206 in the CCA cell line TFK-1 was due to inhibition of AKT1 and AKT2, because knockdown of either AKT1 or AKT2, but not AKT3, showed a synergistic reduction of cell proliferation in combination with mTOR treatment. Finally, using an AKT isoform specific in vitro kinase assay, enzymatic activity of each of the three AKT isoforms was detected in all tissue samples from CCA patients, analyzed. In summary, our preclinical data suggest that combined targeting of mTOR and AKT using RAD001 and MK-2206 might be a new, effective strategy for the treatment of CCA.
KW - Animals
KW - Apoptosis
KW - Bile Duct Neoplasms
KW - Bile Ducts, Intrahepatic
KW - Blotting, Western
KW - Cell Cycle
KW - Cell Proliferation
KW - Cholangiocarcinoma
KW - Drug Synergism
KW - Flow Cytometry
KW - Heterocyclic Compounds, 3-Ring
KW - Humans
KW - Immunoprecipitation
KW - Mice
KW - Phosphatidylinositol 3-Kinase
KW - Protein Kinase Inhibitors
KW - Proto-Oncogene Proteins c-akt
KW - Signal Transduction
KW - Sirolimus
KW - TOR Serine-Threonine Kinases
KW - Tumor Cells, Cultured
KW - Tumor Stem Cell Assay
U2 - 10.1002/ijc.28214
DO - 10.1002/ijc.28214
M3 - SCORING: Journal article
C2 - 23588885
VL - 133
SP - 2065
EP - 2076
JO - INT J CANCER
JF - INT J CANCER
SN - 0020-7136
IS - 9
ER -
