title: Pilot and feasibility study: prospective proteomic profiling of mammary epithelial cells from high-risk women provides evidence of activation of pro-survival pathways.
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.
authors.affiliation: Division of Medical Oncology, Duke University Medical Center, Box 2628, Durham, NC 27710, USA. ibarr001@mc.duke.edu
authors.forename: Catherine
authors.initials: C
authors.lastname: Ibarra-Drendall
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Troch
authors.forename: William T
authors.initials: WT
authors.lastname: Barry
authors.forename: Gloria
authors.initials: G
authors.lastname: Broadwater
authors.forename: Emanuel F
authors.initials: EF
authors.lastname: Petricoin
authors.forename: Julia
authors.initials: J
authors.lastname: Wulfkuhle
authors.forename: Lance A
authors.initials: LA
authors.lastname: Liotta
authors.forename: Siya
authors.initials: S
authors.lastname: Lem
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Baker
authors.forename: Anne C
authors.initials: AC
authors.lastname: Ford
authors.forename: Lee G
authors.initials: LG
authors.lastname: Wilke
authors.forename: Carola
authors.initials: C
authors.lastname: Zalles
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Kuderer
authors.forename: Abigail W
authors.initials: AW
authors.lastname: Hoffman
authors.forename: Melanie
authors.initials: M
authors.lastname: Shivraj
authors.forename: Priya
authors.initials: P
authors.lastname: Mehta
authors.forename: Jamila
authors.initials: J
authors.lastname: Williams
authors.forename: Nora
authors.initials: N
authors.lastname: Tolbert
authors.forename: Laurie W
authors.initials: LW
authors.lastname: Lee
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Pilie
authors.forename: Dihua
authors.initials: D
authors.lastname: Yu
authors.forename: Victoria L
authors.initials: VL
authors.lastname: Seewaldt
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000032:analysis*; D044963:Biopsy, Fine-Needle; D001943:Breast Neoplasms / Q000737:chemistry* / Q000473:pathology; D018797:Cell Cycle Proteins / Q000032:analysis*; D002470:Cell Survival; D016000:Cluster Analysis; D005240:Feasibility Studies; D005260:Female; D057166:High-Throughput Screening Assays; D006801:Humans; D016015:Logistic Models; D042361:Mammary Glands, Human / Q000737:chemistry* / Q000473:pathology; D042282:Microdissection; D008875:Middle Aged; D009657:North Carolina; D010865:Pilot Projects; D011446:Prospective Studies; D040081:Protein Array Analysis; D040901:Proteomics / Q000379:methods; D018570:Risk Assessment; D012307:Risk Factors; D015398:Signal Transduction
chemical_list: D051017:Apoptosis Regulatory Proteins; D018797:Cell Cycle Proteins