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Breast cancer proteomics by laser capture microdissection, sample pooling, 54‐cm IPG IEF, and differential iodine radioisotope detection
Author(s) -
Neubauer Hans,
Clare Susan E.,
Kurek Raffael,
Fehm Tanja,
Wallwiener Diethelm,
Sotlar Karl,
Nordheim Alfred,
Wozny Wojciech,
Schwall Gerhard P.,
Poznanović Slobodan,
Sastri Chaturvedula,
Hunzinger Christian,
Stegmann Werner,
Schrattenholz André,
Cahill Michael A.
Publication year - 2006
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200500739
Subject(s) - laser capture microdissection , proteomics , multiplex , estrogen receptor , cancer , chemistry , biology , tamoxifen , cancer research , microbiology and biotechnology , breast cancer , biochemistry , bioinformatics , gene expression , genetics , gene
The presence of progesterone receptor (PR) in estrogen receptor (ER)‐positive breast cancer is associated with a good prognosis, and indicates that tumors are likely to respond to tamoxifen. However, ER + /PR − tumors respond less well. To reveal the potential molecular mechanism of this phenomenon, we sought to identify differential protein abundances between invasive ductal carcinoma cells from cryopreserved ER + /PR + and ER + /PR − mammary tumor specimens. Because current proteomics methods are hampered in the examination of most primary human tumor samples by the extreme tissue heterogeneity, we used laser capture microdissection (LCM) to isolate tumor cells and developed a sample pooling strategy to analyze small sample protein lysates. Proteins from LCM‐harvested tumors were pooled into four sub‐pools from each condition of three tumors/sub‐pool, and proteins from respective paired sub‐pools were co‐electrophoresed by 2‐DE using 54‐cm IEF over pH 4–9. Abundance ratios were accurately quantified by a differential multiplex radioactive ProteoTope method at low attomole levels (∼3.6 &μ;g protein per labeling reaction, <180 ng per multiplex protein sample per 54‐cm gel). Applying this approach, differentially displayed proteins were identified by MS using comigrating non‐radioactively labeled tumor proteins. They include decreased cytochrome b 5 and transgelin, and more abundant CRABP‐II, cyclophilin A, Neudesin, and hemoglobin in ER + /PR + tumors versus ER + /PR − providing a possible explanation for differential susceptibility against tamoxifen as a result of deregulated cytochrome b 5 ‐dependent metabolism. This study demonstrates the potential of ProteoTope and LCM to enable extremely sensitive and precise differential analyses from well‐defined primary clinical specimen.