Towards a lung adenocarcinoma proteome map: Studies with SP-C/c-raf transgenic mice

We report mapping of proteins of adenocarcinomas of the lung as a result of overexpression of the oncogenically activated N-terminal deletion mutant c-raf-1 BxB through usage of the human SP-C promotor. Proteins from non-transgenic controls and tumors were extracted with a lysis buffer containing 5 mol/L urea, 2 mol/L thiourea, 40 mmol/L Tris, 4% CHAPS, 100 mmol/L DTT, 0.5% BioLyte 3-10, separated by 2-DE and studied by image analysis. On average, 300-600 protein spots per gel were excised and analyzed by MALDI-TOF and -TOF/TOF MS. More than 1000 of the CBB-stained proteins were identified and traced back to 100 different gene products, including many of their isoforms. We observed significant changes in the expression of proteins involved in cellular defense or glycolysis, and this included glutathione S-transferase, peroxiredoxin 6, and alpha-enolase, among others. Proteins associated with lung tumor growth and/or metastasis, i.e., lung carbonyl reductase, differed in expression, as did tumor-associated expression of cell adhesion and membrane-bound proteins such as vinculin. This map provides valuable insight into expression of pulmonary proteins associated with lung adenocarcinomas, some of which may be of utility as diagnostic markers in clinical trials.