title: Vertical blockade of the IGFR- PI3K/Akt/mTOR pathway for the treatment of hepatocellular carcinoma: the role of survivin.
abstract: BACKGROUND
  To explore whether combining inhibitors that target the insulin-like growth factor receptor (IGFR)/PI3K/Akt/mTOR signaling pathway (vertical blockade) can improve treatment efficacy for hepatocellular carcinoma (HCC).
  
  
  METHODS
  HCC cell lines (including Hep3B, Huh7, and PLC5) and HUVECs (human umbilical venous endothelial cells) were tested. The molecular targeting therapy agents tested included NVP-AEW541 (IGFR kinase inhibitor), MK2206 (Akt inhibitor), BEZ235 (PI3K/mTOR inhibitor), and RAD001 (mTOR inhibitor). Potential synergistic antitumor effects were tested by median dose-effect analysis in vitro and by xenograft HCC models. Apoptosis was analyzed by flow cytometry (sub-G1 fraction analysis) and Western blotting. The activities of pertinent signaling pathways and expression of apoptosis-related proteins were measured by Western blotting.
  
  
  RESULTS
  Vertical blockade induced a more sustained inhibition of PI3K/Akt/mTOR signaling activities in all the HCC cells and HUVEC tested. Synergistic apoptosis-inducing effects, however, varied among different cell lines and drug combinations and were most prominent when NVP-AEW541 was combined with MK2206. Using an apoptosis array, we identified survivin as a potential downstream mediator. Over-expression of survivin in HCC cells abolished the anti-tumor synergy between NVP-AEW541 and MK2206, whereas knockdown of survivin improved the anti-tumor effects of all drug combinations tested. In vivo by xenograft studies confirmed the anti-tumor synergy between NVP-AEW541 and MK2206 and exhibited acceptable toxicity profiles.
  
  
  CONCLUSIONS
  Vertical blockade of the IGFR/PI3K/Akt/mTOR pathway has promising anti-tumor activity for HCC. Survivin expression may serve as a biomarker to predict treatment efficacy.
authors.forename: Da-Liang
authors.initials: DL
authors.lastname: Ou
authors.forename: Bin-Shyun
authors.initials: BS
authors.lastname: Lee
authors.forename: Liang-In
authors.initials: LI
authors.lastname: Lin
authors.forename: Jun-Yang
authors.initials: JY
authors.lastname: Liou
authors.forename: Sheng-Chieh
authors.initials: SC
authors.lastname: Liao
authors.affiliation: Graduate Institute of Oncology, College of Medicine, National Taiwan University, Taipei, Taiwan. hsuchiun@gmail.com.
authors.forename: Chiun
authors.initials: C
authors.lastname: Hsu
authors.forename: Ann-Lii
authors.initials: AL
authors.lastname: Cheng
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D014408:Biomarkers, Tumor / Q000378:metabolism; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000068338:Everolimus; D005434:Flow Cytometry; D006575:Heterocyclic Compounds, 3-Ring / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism*; D008113:Liver Neoplasms / Q000378:metabolism*; D008297:Male; D008807:Mice, Inbred BALB C; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors; D011743:Pyrimidines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D017451:Receptors, Somatomedin / Q000037:antagonists & inhibitors; D015398:Signal Transduction / Q000187:drug effects*; D020123:Sirolimus / Q000031:analogs & derivatives / Q000494:pharmacology; D000077022:Survivin; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; C107489:BIRC5 protein, human; D014408:Biomarkers, Tumor; D004791:Enzyme Inhibitors; D006575:Heterocyclic Compounds, 3-Ring; D007093:Imidazoles; D051034:Inhibitor of Apoptosis Proteins; C548887:MK 2206; C501177:NVP-AEW541; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011743:Pyrimidines; D011758:Pyrroles; D011804:Quinolines; D017451:Receptors, Somatomedin; D000077022:Survivin; D000068338:Everolimus; C546842:MTOR protein, human; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; C531198:dactolisib; D020123:Sirolimus