The mTORC2-Akt1 Cascade Is Crucial for c-Myc to Promote Hepatocarcinogenesis in Mice and Humans

© 2019 by the American Association for the Study of Liver Diseases..

Hepatocellular carcinoma (HCC) is a deadly form of liver cancer with limited treatment options. The c-Myc transcription factor is a pivotal player in hepatocarcinogenesis, but the mechanisms underlying c-Myc oncogenic activity in the liver remain poorly delineated. Mammalian target of rapamycin complex 2 (mTORC2) has been implicated in cancer by regulating multiple AGC kinases, especially AKT proteins. In the liver, AKT1 and AKT2 are widely expressed. While AKT2 is the major isoform downstream of activated phosphoinositide 3-kinase and loss of phosphatase and tensin homolog-induced HCC, the precise function of AKT1 in hepatocarcinogenesis is largely unknown. In the present study, we demonstrate that mTORC2 is activated in c-Myc-driven mouse HCC, leading to phosphorylation/activation of Akt1 but not Akt2. Ablation of Rictor inhibited c-Myc-induced HCC formation in vivo. Mechanistically, we discovered that loss of Akt1, but not Akt2, completely prevented c-Myc HCC formation in mice. Silencing of Rictor or Akt1 in c-Myc HCC cell lines inhibited phosphorylated forkhead box o1 expression and strongly suppressed cell growth in vitro. In human HCC samples, c-MYC activation is strongly correlated with phosphorylated AKT1 expression. Higher expression of RICTOR and AKT1, but not AKT2, is associated with poor survival of patients with HCC. In c-Myc mice, while rapamycin, an mTORC1 inhibitor, had limited efficacy at preventing c-Myc-driven HCC progression, the dual mTORC1 and mTORC2 inhibitor MLN0128 effectively promoted tumor regression by inducing apoptosis and necrosis. Conclusion: Our study indicates the functional contribution of mTORC2/Akt1 along c-Myc-induced hepatocarcinogenesis, with AKT1 and AKT2 having distinct roles in HCC development and progression; targeting both mTORC1 and mTORC2 may be required for effective treatment of human HCC displaying c-Myc amplification or overexpression.

Medienart:

E-Artikel

Erscheinungsjahr:

2019

Erschienen:

2019

Enthalten in:

Zur Gesamtaufnahme - volume:70

Enthalten in:

Hepatology (Baltimore, Md.) - 70(2019), 5 vom: 21. Nov., Seite 1600-1613

Sprache:

Englisch

Beteiligte Personen:

Xu, Zhong [VerfasserIn]
Xu, Meng [VerfasserIn]
Liu, Pin [VerfasserIn]
Zhang, Shu [VerfasserIn]
Shang, Runze [VerfasserIn]
Qiao, Yu [VerfasserIn]
Che, Li [VerfasserIn]
Ribback, Silvia [VerfasserIn]
Cigliano, Antonio [VerfasserIn]
Evert, Katja [VerfasserIn]
Pascale, Rosa M [VerfasserIn]
Dombrowski, Frank [VerfasserIn]
Evert, Matthias [VerfasserIn]
Chen, Xi [VerfasserIn]
Calvisi, Diego F [VerfasserIn]
Chen, Xin [VerfasserIn]

Links:

Volltext

Themen:

AKT1 protein, human
Akt1 protein, mouse
EC 2.7.11.1
Journal Article
MYC protein, human
Mechanistic Target of Rapamycin Complex 2
Myc protein, mouse
Proto-Oncogene Proteins c-akt
Proto-Oncogene Proteins c-myc
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 02.07.2020

Date Revised 28.03.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1002/hep.30697

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM296818224