Histone proteomics reveals novel post-translational modifications in breast cancer.

Histones and their variants are subjected to several post-translational modifications (PTMs). Histones PTMs play an important role in the regulation of gene expression and are critical for the development and progression of many types of cancer, including breast cancer. In this study, we used two-dimensional TAU/SDS electrophoresis, coupled with mass spectrometry for a comprehensive profiling of histone PTMs in breast cancer cell lines.Proteomic approach allowed us to identify 85 histone PTMs, seventeen of which are not reported in the UniProt database. Western blot analysis was performed to confirm a peculiar pattern of PTMs in the sporadic and hereditary breast cancer cell lines compared to normal cells. Overlapping mass spectrometry data with western blotting results, we identified, for the first time to our knowledge, a tyrosine phosphorylation on histone H1, which is significantly higher in breast cancer cells. Additionally, by inhibiting specific signaling paths, such as PI3K, PPARγ and FAK pathways, we established a correlation between their regulation and the presence of new histone PTMs. Our results may provide new insight on the possible implication of these modifications in breast cancer and may offer new perspectives for future clinical applications.

Integration of "Omics" Strategies for Biomarkers Discovery and for the Elucidation of Molecular Mechanisms Underlying Brugada Syndrome.

PURPOSE: The Brugada syndrome (BrS) is a severe inherited cardiac disorder. Given the high genetic and phenotypic heterogeneity of this disease, three different "omics" approaches are integrated in a synergic way to elucidate the molecular mechanisms underlying the pathophysiology of BrS as well as for identifying reliable diagnostic/prognostic markers. EXPERIMENTAL DESIGN: The profiling of plasma Proteome and MiRNome is perfomed in a cohort of Brugada patients that were preliminary subjected to genomic analysis to assess a peculiar gene mutation profile. RESULTS: The integrated analysis of "omics" data unveiled a cooperative activity of mutated genes, deregulated miRNAs and proteins in orchestrating transcriptional and post-translational events that are critical determining factors for the development of the Brugada pattern. CONCLUSIONS AND CLINICAL RELEVANCE: This study provides the basis to shed light on the specific molecular fingerprints underlying BrS development and to gain further insights on the pathogenesis of this life-threatening cardiac disease.

Proteomics Analysis to Assess the Role of Mitochondria in BRCA1-Mediated Breast Tumorigenesis.

Mitochondria are the organelles deputed to energy production, but they are also involved in carcinogenesis, cancer progression, and metastasis, playing a role in altered energy metabolism in cancer cells. Mitochondrial metabolism is connected with several mitochondrial pathways such as ROS signaling, Ca2+ homeostasis, mitophagy, and mitochondrial biogenesis. These pathways are merged in an interactive super-network that seems to play a crucial role in cancer. Germline mutations of the BRCA1 gene account for 5-10% of breast cancers and confer a risk of developing the disease 10- to 20-fold much higher than in non-carriers. By considering metabolic networks that could reconcile both genetic and non-genetic causal mechanisms in BRCA1 driven tumorigenesis, we herein based our study on the hypothesis that BRCA1 haploinsufficiency might drive metabolic rewiring in breast epithelial cells, acting as a push toward malignant transformation. Using 2D-DIGE we analyzed and compared the mitochondrial proteomic profile of sporadic breast cancer cell line (MCF7) and BRCA1 mutated breast cancer cell line (HCC1937). Image analysis was carried out with Decider Software, and proteins differentially expressed were identified by LC-MS/MS on a quadrupole-orbitrap mass spectrometer Q-Exactive. Ingenuity pathways analysis software was used to analyze the fifty-three mitochondrial proteins whose expression resulted significantly altered in response to BRCA1 mutation status. Mitochondrial Dysfunction and oxidative phosphorylation, and energy production and nucleic acid metabolism were, respectively, the canonical pathway and the molecular function mainly affected. Western blotting analysis was done to validate the expression and the peculiar mitochondrial compartmentalization of specific proteins such us HSP60 and HIF-1α. Particularly intriguing is the correlation between BRCA1 mutation status and HIF-1α localization into the mitochondria in a BRCA1 dependent manner. Data obtained led us to hypothesize an interesting connection between BRCA1 and mitochondria pathways, capable to trigger metabolic changes, which, in turn, sustain the high energetic and anabolic requirements of the malignant phenotype.

Unraveling the Mechanistic Complexity of the Glomerulocystic Phenotype in Dicer Conditional KO Mice by 2D Gel Electrophoresis Coupled Mass Spectrometry.

PURPOSE: Dicer, an RNase III type endonuclease, is a key enzyme involved in miRNA biogenesis. It has been shown that this enzyme is essential for several aspects of postnatal kidney functions and homeostasis. In this study, we have examined conditional knockout (cKO) mice for Dicer in Pax8 (Paired-box gene 8) expressing cells to investigate the kidney protein profile. This specific model develops a glomerulocystic phenotype coupled with urinary concentration impairment, proteinuria, and severe renal failure. EXPERIMENTAL DESIGN: Proteomic analysis was performed on kidney tissue extracts from cKO and control (Ctr) mice by 2D Gel Electrophoresis coupled with mass spectrometry. RESULTS: The analysis highlighted 120 protein spots differentially expressed in Dicer cKO tissue compared with control; some of these proteins were validated by Western blotting. Ingenuity Pathway Analysis led to the identification of some interesting networks; among them, the one having ERK as a central hub may explain, through the modulation of the expression of a number of identified protein targets, the metabolic and structural alterations occurring during kidney cyst development in Dicer cKO mouse model. CONCLUSIONS AND CLINICAL RELEVANCE: Our results contribute to gain new insights into molecular mechanisms through which Dicer endonuclease controls kidney development and physiological functions.

Plasma Proteomic Profiling in Hereditary Breast Cancer Reveals a BRCA1-Specific Signature: Diagnostic and Functional Implications.

BACKGROUND: Breast cancer (BC) is a leading cause of death among women. Among the major risk factors, an important role is played by familial history of BC. Germ-line mutations in BRCA1/2 genes account for most of the hereditary breast and/or ovarian cancers. Gene expression profiling studies have disclosed specific molecular signatures for BRCA1/2-related breast tumors as compared to sporadic cases, which might help diagnosis and clinical follow-up. Even though, a clear hallmark of BRCA1/2-positive BC is still lacking. Many diseases are correlated with quantitative changes of proteins in body fluids. Plasma potentially carries important information whose knowledge could help to improve early disease detection, prognosis, and response to therapeutic treatments. The aim of this study was to develop a comprehensive approach finalized to improve the recovery of specific biomarkers from plasma samples of subjects affected by hereditary BC. METHODS: To perform this analysis, we used samples from patients belonging to highly homogeneous population previously reported. Depletion of high abundant plasma proteins, 2D gel analysis, liquid chromatography-tandem mass spectrometry (LC-MS/MS) and bioinformatics analysis were used into an integrated approach to investigate tumor-specific changes in the plasma proteome of BC patients and healthy family members sharing the same BRCA1 gene founder mutation (5083del19), previously reported by our group, with the aim to identify specific signatures. RESULTS: The comparative analysis of the experimental results led to the identification of gelsolin as the most promising biomarker. CONCLUSIONS: Further analyses, performed using a panel of breast cancer cell lines, allowed us to further elucidate the signaling network that might modulate the expression of gelsolin in breast cancer.

Proteomics-driven analysis of ovine whey colostrum.

The aim of this study was to shed light in to the complexity of the ovine colostrum proteome, with a specific focus on the low abundance proteins. The ovine colostrum is characterized by a few dominating proteins, as the immunoglobulins, but it also contains less represented protein species, equally important for the correct development of neonates. Ovine colostrum, collected immediately after lambing, was separated by 1D SDS-PAGE. Proteins bands were digested with trypsin and the resulting peptides were analyzed by LC-MS/MS. On the basis of the Swiss-Prot database, a total of 343 unique proteins were identified. To our knowledge, this study represents the most comprehensive analysis of ovine colostrum proteome.