Function of RasGRP3 in the formation and progression of human breast cancer

Molecular Cancer

Research

Gabriella Czifra¹  Tamás Bíró¹  Zsuzsanna Nagy¹  György Vereb²  István Juhász³  Miklós Török⁴  Ilona Kovács⁴  Dezső Tóth⁵  Krisztina Buzás⁶  Peter M Blumberg⁷ 

[1] DE-MTA “Lendület” Cellular Physiology Research Group, Department of Physiology, Medical and Health Science Center, Research Center for Molecular Medicine, University of Debrecen, PO Box 22, Nagyerdei krt. 98, H-4032, Debrecen, Hungary;Department of Biophysics and Cell Biology, Medical and Health Science Center, Faculty of Medicine, University of Debrecen, Debrecen, Hungary;Department of Dermatology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary;Department of Pathology, Gyula Kenézy Hospital, Debrecen, Hungary;Department of Surgery, Gyula Kenézy Hospital, Debrecen, Hungary;Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary;Laboratory of Cancer Biology and Genetics Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA;

关键词: Ras activator;    RasGRP3;    Human breast cancer;    Chemotherapeutic resistance;    Tamoxifen;    Trastuzumab;    Tumorigenesis;    EGF;    IGF-I;    Signaling pathways;   

DOI  :  10.1186/1476-4598-13-96

 received in 2013-11-27, accepted in 2014-04-21,  发布年份 2014

来源: Springer

【 摘 要 】

IntroductionRas guanine nucleotide exchange factors (RasGEFs) mediate the activation of the Ras signaling pathway that is over activated in many human cancers. The RasGRP3, an activator of H-Ras and R-Ras protein exerts oncogenic effects and the overexpression of the protein is observed in numerous malignant cancer types. Here, we investigated the putative alteration of expression and potential function of RasGRP3 in the formation and progression of human breast cancer.MethodsThe RasGRP3 and phosphoRasGRP3 expressions were examined in human invasive ductal adenocarcinoma derived samples and cell lines (BT-474, JIMT-1, MCF7, SK-BR-3, MDA-MB-453, T-47D) both in mRNA (Q-PCR) and protein (Western blot; immunohistochemistry) levels. To explore the biological function of the protein, RasGRP3 knockdown cultures were established. To assess the role of RasGRP3 in the viability of cells, annexin-V/PI staining and MitoProbe™ DilC1 (5) assay were performed. To clarify the function of the protein in cell proliferation and in the development of chemotherapeutic resistance, CyQuant assay was performed. To observe the RasGRP3 function in tumor formation, the Severe combined immunodeficiency (SCID) mouse model was used. To investigate the role of the protein in Ras-related signaling Q-PCR and Western blot experiments were performed.ResultsRasGRP3 expression was elevated in human breast tumor tissue samples as well as in multiple human breast cancer cell lines. Down-regulation of RasGRP3 expression in breast cancer cells decreased cell proliferation, induced apoptosis in MCF7 cells, and sensitized T-47D cells to the action of drugs Tamoxifen and trastuzumab (Herceptin). Gene silencing of RasGRP3 reduced tumor formation in mouse xenografts as well. Inhibition of RasGRP3 expression also reduced Akt, ERK1/2 and estrogen receptor alpha phosphorylation downstream from IGF-I insulin like growth factor-I (IGF-I) or epidermal growth factor (EGF) stimulation confirming the functional role of RasGRP3 in the altered behavior of these cells.ConclusionsTaken together, our results suggest that the Ras activator RasGRP3 may have a role in the pathological behavior of breast cancer cells and may constitute a therapeutic target for human breast cancer.

【 授权许可】

Unknown   
© Nagy et al.; licensee BioMed Central Ltd. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.