Combined Proteomic-Transcriptomic Profiling of Laser Capture Microdissected Normal and Breast Cancer Epithelium Reveals Systematic Biochemical Network Alterations
M Imielinski, S Cha, EA Richardson, D Thakur, T Rejtar, S-L Wu, B Karger, D Sgroi. Massachusetts General Hospital, Boston, MA; Northeastern University, Boston, MA
Background: Global profiling studies in solid tumors are ideally carried out on purified cell populations, such as those obtained through laser capture microdissection (LCM). Proteomic analysis of LCM samples has been traditionally limited by the sensitivity of standard analytic methods and the small amounts of tissue isolated through LCM. We have recently optimized an analytic method employing nano-LC-MS/MS to globally profile proteins in LCM tissue with a high degree of sensitivity and quantitative resolution.
Design: We profiled the proteomes of 10 estrogen receptor (ER) positive invasive ductal breast carcinoma (IDC) and 10 mammoplasty LCM specimens. We analyzed significant proteomic alterations in the context of known biochemical networks obtained from the Ingenuity Pathway database and global gene expression profiles measured in a parallel LCM breast cancer dataset.
Results: We identified 468 proteins significantly altered (289 up and 179 down) between IDC and normal epithelium (FDR<0.1). These proteins were related via multiple canonical pathways and biochemical networks obtained from the Ingenuity pathway database. IDC proteomes were altered in cavolear mediated endocytosis signaling (P<10-10) and small molecule metabolism (P<0.05) pathways. An ensemble of the most significant (P<10-30) protein-derived Ingenuity networks was significantly enriched for genes exhibiting differential mRNA expression between LCM IDC and normal breast epithelium (P<0.05). The network with the highest concordance between protein and gene expression profiles was centered at the angiotensin-II receptor, a druggable target recently implicated in breast carcinogenesis (Figure 1). Figure 1 Combined proteomic-transcriptomic analysis identifies an altered network around the angiotensin II receptor.
Conclusions: Combined proteomic and transcriptomic profiling of LCM dissected tissue revealed molecular alterations associated with breast cancer. These alterations cluster into networks that suggest novel pathophysiology and diagnostic / therapeutic targets.
Monday, March 22, 2010 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 20, Monday Morning