Distinct functional roles of Akt isoforms for proliferation, survival, migration and EGF-mediated signalling in lung cancer derived disseminated tumor cells

TY - JOUR

T1 - Distinct functional roles of Akt isoforms for proliferation, survival, migration and EGF-mediated signalling in lung cancer derived disseminated tumor cells

AU - Grabinski, Nicole

AU - Bartkowiak, Kai

AU - Grupp, Katharina

AU - Brandt, Burkhard

AU - Pantel, Klaus

AU - Jücker, Manfred

N1 - Copyright © 2011 Elsevier Inc. All rights reserved.

PY - 2011/12

Y1 - 2011/12

N2 - Single disseminated tumor cells (DTC) can be detected in the bone marrow (BM) from 20% to 60% of patients with various tumors including non-small cell lung cancer (NSCLC). Detection of DTC in the BM of NSCLC patients is associated with poor prognosis and may be responsible for metastatic relapse. However, the functional properties of DTC are widely unknown. Here, we performed the first functional analysis of DTC focusing on the activation of the PI3K/Akt signalling pathway and the functional roles of Akt isoforms. In vitro kinase assays revealed a high activity of Akt3 in NSCLC-derived DTC. Proliferation and survival of DTC was reduced by depletion of Akt3 and to a lesser extend by Akt1, but not after depletion of Akt2. The major effect of Akt3 on the proliferation of DTC was associated with an Akt3-mediated regulation of both, cyclin D1 and cyclin D3, whereas Akt1 regulated the expression of cyclin D1 only. In contrast all three Akt isoforms, especially Akt2, were involved in the regulation of migration. Analysis of signalling events downstream of distinct Akt isoforms revealed that expression levels of urokinase-type plasminogen activator and its receptor were decreased after knockdown of Akt1 and Akt3. In addition, EGF-stimulated proliferative and anti-apoptotic signals are mediated by Akt1 and Akt3 in DTC. Finally, by immunofluorescence staining of primary DTC from BM samples of lung cancer patients, pAkt(S473) and Akt3 positive DTC were detected in vivo. Our data demonstrate that Akt1 and notably Akt3 regulate proliferation, survival, migration and EGF-mediated signal transduction in NSCLC-derived DTC.

AB - Single disseminated tumor cells (DTC) can be detected in the bone marrow (BM) from 20% to 60% of patients with various tumors including non-small cell lung cancer (NSCLC). Detection of DTC in the BM of NSCLC patients is associated with poor prognosis and may be responsible for metastatic relapse. However, the functional properties of DTC are widely unknown. Here, we performed the first functional analysis of DTC focusing on the activation of the PI3K/Akt signalling pathway and the functional roles of Akt isoforms. In vitro kinase assays revealed a high activity of Akt3 in NSCLC-derived DTC. Proliferation and survival of DTC was reduced by depletion of Akt3 and to a lesser extend by Akt1, but not after depletion of Akt2. The major effect of Akt3 on the proliferation of DTC was associated with an Akt3-mediated regulation of both, cyclin D1 and cyclin D3, whereas Akt1 regulated the expression of cyclin D1 only. In contrast all three Akt isoforms, especially Akt2, were involved in the regulation of migration. Analysis of signalling events downstream of distinct Akt isoforms revealed that expression levels of urokinase-type plasminogen activator and its receptor were decreased after knockdown of Akt1 and Akt3. In addition, EGF-stimulated proliferative and anti-apoptotic signals are mediated by Akt1 and Akt3 in DTC. Finally, by immunofluorescence staining of primary DTC from BM samples of lung cancer patients, pAkt(S473) and Akt3 positive DTC were detected in vivo. Our data demonstrate that Akt1 and notably Akt3 regulate proliferation, survival, migration and EGF-mediated signal transduction in NSCLC-derived DTC.

KW - Humans

KW - Female

KW - Cell Line, Tumor

KW - Gene Expression

KW - Gene Knockdown Techniques

KW - Phosphorylation

KW - Cell Proliferation

KW - Signal Transduction

KW - Bone Marrow Neoplasms/metabolism/physiopathology/secondary

KW - Breast Neoplasms/pathology

KW - Carcinoma, Non-Small-Cell Lung/metabolism/physiopathology/secondary

KW - Cell Movement

KW - Cell Survival

KW - Enzyme Assays

KW - Epidermal Growth Factor/pharmacology/physiology

KW - Glycogen Synthase Kinase 3/metabolism

KW - Isoenzymes/metabolism

KW - Lung Neoplasms/pathology

KW - Proto-Oncogene Proteins c-akt/genetics/metabolism

KW - RNA Interference

KW - Receptor, Epidermal Growth Factor/metabolism

KW - Receptor, erbB-2/metabolism

KW - Receptor, erbB-3/metabolism

KW - Receptors, Urokinase Plasminogen Activator/genetics/metabolism

KW - Urokinase-Type Plasminogen Activator/genetics/metabolism

KW - Humans

KW - Female

KW - Cell Line, Tumor

KW - Gene Expression

KW - Gene Knockdown Techniques

KW - Phosphorylation

KW - Cell Proliferation

KW - Signal Transduction

KW - Bone Marrow Neoplasms/metabolism/physiopathology/secondary

KW - Breast Neoplasms/pathology

KW - Carcinoma, Non-Small-Cell Lung/metabolism/physiopathology/secondary

KW - Cell Movement

KW - Cell Survival

KW - Enzyme Assays

KW - Epidermal Growth Factor/pharmacology/physiology

KW - Glycogen Synthase Kinase 3/metabolism

KW - Isoenzymes/metabolism

KW - Lung Neoplasms/pathology

KW - Proto-Oncogene Proteins c-akt/genetics/metabolism

KW - RNA Interference

KW - Receptor, Epidermal Growth Factor/metabolism

KW - Receptor, erbB-2/metabolism

KW - Receptor, erbB-3/metabolism

KW - Receptors, Urokinase Plasminogen Activator/genetics/metabolism

KW - Urokinase-Type Plasminogen Activator/genetics/metabolism

U2 - 10.1016/j.cellsig.2011.07.003

DO - 10.1016/j.cellsig.2011.07.003

M3 - SCORING: Journal article

C2 - 21777670

VL - 23

SP - 1952

EP - 1960

JO - CELL SIGNAL

JF - CELL SIGNAL

SN - 0898-6568

IS - 12

M1 - 12

ER -