[HTML][HTML] The Akt1/IL-6/STAT3 pathway regulates growth of lung tumor initiating cells

D Malanga, C De Marco, I Guerriero, F Colelli… - Oncotarget, 2015 - ncbi.nlm.nih.gov
D Malanga, C De Marco, I Guerriero, F Colelli, N Rinaldo, M Scrima, T Mirante, C De Vitis
Oncotarget, 2015ncbi.nlm.nih.gov
Here we report that the PI3K/Akt1/IL-6/STAT3 signalling pathway regulates generation and
stem cell-like properties of Non-Small Cell Lung Cancer (NSCLC) tumor initiating cells
(TICs). Mutant Akt1, mutant PIK3CA or PTEN loss enhances formation of lung cancer
spheroids (LCS), self-renewal, expression of stemness markers and tumorigenic potential of
human immortalized bronchial cells (BEAS-2B) whereas Akt inhibition suppresses these
activities in established (NCI-H460) and primary NSCLC cells. Matched microarray analysis …
Abstract
Here we report that the PI3K/Akt1/IL-6/STAT3 signalling pathway regulates generation and stem cell-like properties of Non-Small Cell Lung Cancer (NSCLC) tumor initiating cells (TICs). Mutant Akt1, mutant PIK3CA or PTEN loss enhances formation of lung cancer spheroids (LCS), self-renewal, expression of stemness markers and tumorigenic potential of human immortalized bronchial cells (BEAS-2B) whereas Akt inhibition suppresses these activities in established (NCI-H460) and primary NSCLC cells. Matched microarray analysis of Akt1-interfered cells and LCSs identified IL-6 as a critical target of Akt signalling in NSCLC TICs. Accordingly, suppression of Akt in NSCLC cells decreases IL-6 levels, phosphorylation of IkK and IkB, NF-kB transcriptional activity, phosphorylation and transcriptional activity of STAT3 whereas active Akt1 up-regulates them. Exposure of LCSs isolated from NSCLC cells to blocking anti-IL-6 mAbs, shRNA to IL-6 receptor or to STAT3 markedly reduces the capability to generate LCSs, to self-renew and to form tumors, whereas administration of IL-6 to Akt-interfered cells restores the capability to generate LCSs. Finally, immunohistochemical studies in NSCLC patients demonstrated a positive correlative trend between activated Akt, IL-6 expression and STAT3 phosphorylation (n= 94; p< 0.05). In conclusion, our data indicate that aberrant Akt signalling contributes to maintaining stemness in lung cancer TICs through a NF-kB/IL-6/STAT3 pathway and provide novel potential therapeutic targets for eliminating these malignant cells in NSCLC.
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