ABSTRACT
Although doxorubicin (Doxo) and docetaxel (Docet) in combination are widely used in treatment regimens for a broad spectrum of breast cancer patients, a major obstacle has emerged in that some patients are intrinsically resistant to these chemotherapeutics. Our study aimed to discover potential prediction markers of drug resistance in needle-biopsied tissues of breast cancer patients prior to neoadjuvant chemotherapy. Tissues collected before chemotherapy were analyzed by mass spectrometry. A total of 2,331 proteins were identified and comparatively quantified between drug sensitive (DS) and drug resistant (DR) patient groups by spectral count. Of them, 298 proteins were differentially expressed by more than 1.5-fold. Some of the differentially expressed proteins (DEPs) were further confirmed by Western blotting. Bioinformatic analysis revealed that the DEPs were largely associated with drug metabolism, acute phase response signaling, and fatty acid elongation in mitochondria. Clinical validation of two selected proteins by immunohistochemistry found that FKBP4 and S100A9 might be putative prediction markers in discriminating the DR group from the DS group of breast cancer patients. The results demonstrate that a quantitative proteomics/bioinformatics approach is useful for discovering prediction markers of drug resistance, and possibly for the development of a new therapeutic strategy.
Subject(s)
Biomarkers, Tumor/analysis , Breast Neoplasms/drug therapy , Breast Neoplasms/metabolism , Calgranulin B/analysis , Proteome/analysis , Tacrolimus Binding Proteins/analysis , Amino Acid Sequence , Biomarkers, Tumor/metabolism , Blotting, Western , Calgranulin B/metabolism , Chemotherapy, Adjuvant , Cluster Analysis , Drug Resistance, Neoplasm , Female , Humans , Immunohistochemistry , Molecular Sequence Data , Neoadjuvant Therapy , Proteome/metabolism , Proteomics , Reproducibility of Results , Statistics, Nonparametric , Tacrolimus Binding Proteins/metabolism , Tandem Mass Spectrometry , Treatment OutcomeABSTRACT
Absence seizure has been of interest because the symptom is related to sensory processing. However, the mechanism that causes the disease is not understood yet. To better understand the molecular mechanism related to the disease progress at protein level, we performed proteomic studies using the thalamus of mice for which absence seizure was induced by gamma-butyrolactone (GBL). Differential proteome expression between GBL-treated mice and control mice was examined by fluorescence 2D difference gel electrophoresis (DIGE) at three different time points (5, 10, and 30 min) after GBL-administration. We identified 16 proteins differentially expressed by >1.4-fold at any of the three time points. All proteins besides the serine protease inhibitor EIA were down-regulated in absence seizure-induced mice. The down-regulated proteins can be classified into five groups by their biological functions: cytoskeleton rearrangement, neuroprotection, neurotransmitter secretion, calcium binding, and metabolism. The maximum level of change was reached by 10 min after GBL-treatment, with the expression level returning back to the original at 30 min when mice were awakened from absence seizure thereby demonstrating the proteomic response is reversible. Our results suggest that absence seizures are associated with restricted functional sets of proteins, whose down-regulation may interfere with general function of neuronal cells.