Runx2 activates PI3K-Akt signaling via mTORC2 regulation in invasive breast cancer cellsReport as inadecuate




Runx2 activates PI3K-Akt signaling via mTORC2 regulation in invasive breast cancer cells - Download this document for free, or read online. Document in PDF available to download.

Breast Cancer Research

, 16:R16

First Online: 30 January 2014Received: 14 June 2013Accepted: 22 January 2014DOI: 10.1186-bcr3611

Cite this article as: Tandon, M., Chen, Z. & Pratap, J. Breast Cancer Res 2014 16: R16. doi:10.1186-bcr3611

Abstract

IntroductionThe Runt-related transcription factor Runx2 is critical for skeletal development but is also aberrantly expressed in breast cancers, and promotes cell growth and invasion. A de-regulated serine-threonine kinase Akt signaling pathway is implicated in mammary carcinogenesis and cell survival; however, the mechanisms underlying Runx2 role in survival of invasive breast cancer cells are still unclear.

MethodsThe phenotypic analysis of Runx2 function in cell survival was performed by gene silencing and flow cytometric analysis in highly invasive MDA-MB-231 and SUM-159-PT mammary epithelial cell lines. The expression analysis of Runx2 and pAkt serine 473 proteins in metastatic breast cancer specimens was performed by immunohistochemistry. The mRNA and protein levels of kinases and phosphatases functional in Akt signaling were determined by real-time PCR and Western blotting, while DNA-protein interaction was studied by chromatin immunoprecipitation assays.

ResultsThe high Runx2 levels in invasive mammary epithelial cell lines promoted cell survival in Akt phosphorylation pAkt-serine 473 dependent manner. The analysis of kinases and phosphatases associated with pAkt regulation revealed that Runx2 promotes pAkt levels via mammalian target of rapamycin complex-2 mTORC2. The recruitment of Runx2 on mTOR promoter coupled with Runx2-dependent expression of mTORC2 component Rictor defined Runx2 function in pAkt-mediated survival of invasive breast cancer cells.

ConclusionsOur results identified a novel mechanism of Runx2 regulatory crosstalk in Akt signaling that could have important consequences in targeting invasive breast cancer-associated cell survival.

AbbreviationsAdAdenovirus

AktSerine-threonine-specific protein kinase PKB

CAConstitutively active

CBFβCore binding protein β subunit

CBPCREB-binding protein

ChIPChromatin immuno precipitation

EGFEpidermal growth factor

EREstrogen receptor

ERKExtracellular signal regulated kinase

FBSFetal bovine serum

FOXO1Forkhead box protein o1

GFPGreen fluorescent protein

GβLG-protein β subunit-like protein mTOR associated protein

HDACHistone deacetylase

Her2Human epidermal growth factor receptor-2

MMPMatrix metalloproteinase

mTORMammalian target of rapamycin

mTORC2Mammalian target of rapamycin complex-2

MTTTetrazolium dye for colorimetric assay

NLSNuclear localization signal

NMTSNuclear matrix targeting signal

p300E1A binding 300 kDA protein

p53Protein 53

PBSPhosphate-buffered saline

PCRPolymerase chain reaction

PDK1Phosphoinositide-dependent protein kinase-1

PHLPP1PH domain leucine-rich repeat protein phosphatase-1

PI3KPhosphatidyl inositol 3′ kinase

PRProgesterone receptor

Runx2Runt-related transcription factor-2

SerSerine

shRNAShort hairpin RNA

siRNASmall interfering RNA

ThrThreonine

WTWild type.

Electronic supplementary materialThe online version of this article doi:10.1186-bcr3611 contains supplementary material, which is available to authorized users.

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Author: Manish Tandon - Zujian Chen - Jitesh Pratap

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







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