Preclinical study

Breast Cancer Research and Treatment

, Volume 132, Issue 2, pp 487-498

Pilot and feasibility study: prospective proteomic profiling of mammary epithelial cells from high-risk women provides evidence of activation of pro-survival pathways

  • Catherine Ibarra-DrendallAffiliated withDivision of Medical Oncology, Duke University Medical Center Email author 
  • , Michelle M. TrochAffiliated withDivision of Medical Oncology, Duke University Medical Center
  • , William T. BarryAffiliated withDepartment of Biostatistics & Bioinformatics, Duke University Medical Center
  • , Gloria BroadwaterAffiliated withDepartment of Biostatistics & Bioinformatics, Duke University Medical Center
  • , Emanuel F. PetricoinIIIAffiliated withCenter for Applied Proteomics and Molecular Medicine, George Mason University
  • , Julia WulfkuhleAffiliated withCenter for Applied Proteomics and Molecular Medicine, George Mason University
  • , Lance A. LiottaAffiliated withCenter for Applied Proteomics and Molecular Medicine, George Mason University
  • , Siya LemAffiliated withDivision of Medical Oncology, Duke University Medical Center
  • , Joseph C. BakerJr.Affiliated withDivision of Medical Oncology, Duke University Medical Center
    • , Anne C. FordAffiliated withDepartment of Obstetrics and Gynecology, Duke University Medical Center
    • , Lee G. WilkeAffiliated withDivision of General Surgery, University of Wisconsin
    • , Carola ZallesAffiliated withTexas A&M Health Sciences Center, College of Medicine
    • , Nicole M. KudererAffiliated withDivision of Medical Oncology, Duke University Medical Center
    • , Abigail W. HoffmanAffiliated withDivision of Medical Oncology, Duke University Medical Center
    • , Melanie ShivrajAffiliated withDivision of Medical Oncology, Duke University Medical Center
    • , Priya MehtaAffiliated withDivision of Medical Oncology, Duke University Medical Center
    • , Jamila WilliamsAffiliated withDivision of Medical Oncology, Duke University Medical Center
    • , Nora TolbertAffiliated withDivision of Medical Oncology, Duke University Medical Center
    • , Laurie W. LeeAffiliated withDivision of Medical Oncology, Duke University Medical Center
    • , Patrick G. PilieAffiliated withDivision of Medical Oncology, Duke University Medical Center
    • , Dihua YuAffiliated withDepartment of Molecular and Cellular Oncology, MD Anderson Cancer Center
    • , Victoria L. SeewaldtAffiliated withDivision of Medical Oncology, Duke University Medical Center

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Abstract

Normal mammary gland homeostasis requires the coordinated regulation of protein signaling networks. However, we have little prospective information on whether activation of protein signaling occurs in premalignant mammary epithelial cells, as represented by cells with cytological atypia from women who are at high risk for breast cancer. This information is critical for understanding the role of deregulated signaling pathways in the initiation of breast cancer and for developing targeted prevention and/or treatment strategies for breast cancer in the future. In this pilot and feasibility study, we examined the expression of 52 phosphorylated, total, and cleaved proteins in 31 microdissected Random Periareolar Fine Needle Aspiration (RPFNA) samples by high-throughput Reverse Phase Protein Microarray. Unsupervised hierarchical clustering analysis indicated the presence of four clusters of proteins that represent the following signaling pathways: (1) receptor tyrosine kinase/Akt/mammalian target of rapamycin (RTK/Akt/mTOR), (2) RTK/Akt/extracellular signal-regulated kinase (RTK/Akt/ERK), (3) mitochondrial apoptosis, and (4) indeterminate. Clusters 1 through 3 comprised moderately to highly expressed proteins, while Cluster 4 comprised proteins that are lowly expressed in a majority of RPFNA samples. Our exploratory study showed that the interlinked components of mitochondrial apoptosis pathway are highly expressed in all mammary epithelial cells obtained from high-risk women. In particular, the expression levels of anti-apoptotic Bcl-xL and pro-apoptotic Bad are positively correlated in both non-atypical and atypical samples (unadjusted P < 0.0001), suggesting a delicate balance between the pro-apoptotic and anti-apoptotic regulation of cell proliferation during the early steps of mammary carcinogenesis. Our feasibility study suggests that the activation of key proteins along the RTK/Akt pathway may tip this balance to cell survival. Taken together, our results demonstrate the feasibility of mapping proteomic signaling networks in limited RPFNA samples obtained from high-risk women and the promise of developing rational drug targets or preventative strategies for breast cancer in future proteomic studies with a larger cohort of high-risk women.

Keywords

Breast cancer risk Atypical mammary cytology Protein microarray Biomarker development Cell survival