Baicalein increases the expression and reciprocal interplay of RUNX3 and FOXO3a through crosstalk of AMPKα and MEK-ERK1-2 signaling pathways in human non-small cell lung cancer cellsReport as inadecuate




Baicalein increases the expression and reciprocal interplay of RUNX3 and FOXO3a through crosstalk of AMPKα and MEK-ERK1-2 signaling pathways in human non-small cell lung cancer cells - Download this document for free, or read online. Document in PDF available to download.

Journal of Experimental and Clinical Cancer Research

, 34:41

First Online: 07 May 2015Received: 30 January 2015Accepted: 20 April 2015DOI: 10.1186-s13046-015-0160-7

Cite this article as: Zheng, F., Wu, J., Zhao, S. et al. J Exp Clin Cancer Res 2015 34: 41. doi:10.1186-s13046-015-0160-7

Abstract

BackgroundBaicalein, a natural flavonoid obtained from the Scutellaria baicalensis root, has been reported to inhibit growth of human lung cancer. However, the detailed mechanism underlying this has not been well elucidated.

MethodsCell viability was measured using a 3-4, 5-dimethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide MTT assays. Apoptosis was detected by flow cytometry analysis and caspase 3-7 assays. The expression of RUNX3 and FOXO3a mRNA were measured by real time RT-PCR methods. Western blot analysis was performed to measure the phosphorylation and protein expression of AMP-activated protein kinase alpha AMPKα and extracellular signal-regulated kinase 1-2 ERK1-2, runt-related transcription factor 3 RUNX3 and forkhead box O3a FOXO3a. Silencing of FOXO3a and RUNX3 were performed by small interfering RNA siRNA methods. Exogenous expression of FOXO3a or RUNX3 was carried out by electroporated transfection assays.

ResultsWe showed that baicalein significantly inhibited growth and induced apoptosis of non-small cell lung cancer NSCLC cells in a time- and dose-dependent manner. Baicalein induced RUNX3 and FOXO3a protein expression, and increased phosphorylation of AMPKα and ERK1-2. Moreover, the inhibitors of AMPK and MEK-ERK1-2 reversed the effect of baicalein on RUNX3 and FOXO3a protein expression. Interestingly, while compound C had little effect on blockade of baicalein-induced phosphorylation of ERK1-2, PD98059 significantly abrogated baicalein-induced phosphorylation of AMPKα. Intriguingly, while silencing of RUNX3 abolished the effect of baicalein on expression of FOXO3a and apoptosis, silencing of FOXO3a significantly attenuated baicalein-reduced cell proliferation. On the contrary, overexpression of FOXO3a restored the effect of baicalein on cell growth inhibition in cells silencing of endogenous FOXO3a gene and enhanced the effect of baicalein on RUNX3 protein expression. Finally, exogenous expression of RUNX3 increased FOXO3a protein and strengthened baicalein-induced phosphorylation of ERK1-2.

ConclusionCollectively, our results show that baicalein inhibits growth and induces apoptosis of NSCLC cells through AMPKα- and MEK-ERK1-2-mediated increase and interaction of FOXO3a and RUNX3 protein. The crosstalk between AMPKα and MEK-ERK1-2 signaling pathways, and the reciprocal interplay of FOXO3a and RUNX3 converge on the overall response of baicalein. This study reveals a novel mechanism for regulating FOXO3a and RUNX3 signaling axis in response to baicalein and suggests a new strategy for NSCLC associated targeted therapy.

KeywordsBaicalein NSCLC RUNX3 FOXO3a MEK-ERK1-2 AMPKα AbbreviationsMTT3-4, 5-dimethylthiahiazo -z-y1-3, 5-di-phenytetrazoliumromide

AMPKαAMP-activated protein kinase alpha

TCMTraditional Chinese medicine

FOXOForkhead members of the class O

ERK1-2Extracellular signal-regulated kinase 1-2

siRNASmall interfering RNA

NSCLCNon-small cell lung cancer

FOXO3aForkhead box-O 3a

Runx3Runt-related transcription factor 3

DMSODimethylsulfoxide

PBSPhosphate-buffered saline

RTRoom temperature

qRT-PCRQuantitative Real-Time RT-PCR

MEKMAPK extracellular signaling-regulated kinase ERK kinase

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Author: Fang Zheng - Jingjing Wu - Shunyu Zhao - Qingmei Luo - Qing Tang - LiJun Yang - Liuning Li - WanYing Wu - Swei Sunny Han

Source: https://link.springer.com/







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