Project description:Background: In previous work we discovered that T lymphocytes play a prominent role in the rise of brain metastases of ER-negative breast cancers. In the present study we explored expressional changes due to T cell contact associated with penetration through the BBB for breast cancer cell lines derived from cancers with various affinities for brain. Methods: Differential expression of proteins was identified by comparing the proteomes of the breast cancer cells before and after co-culture with T cells by using liquid chromatography-mass spectrometry (LC-MS). siRNA was used to silence protein expression in the tumor cells and the artificial BBB model was employed to study the effects on passage of the breast carcinoma cell lines. Results: Mass spectrometry-based proteomics revealed significant alterations in the expression of 35 proteins by the breast cancer cell lines upon T cell contact. Among the proteins is coronin-1A, a protein related to cell motility. Knockdown of CORO1A in the breast cancer cells reduced their ability to cross the artificial BBB to 60%. The effects were significantly less for the cell line derived from breast cancer with affinity for brain. The expression of coronin-1A was confirmed by immunohistochemistry and RT-PCR of 52 breast cancer samples of patients with metastasized breast cancers, with and without brain locations. Lastly, CORO1A upregulation was validated in a publicly available mRNA expression database from 204 primary breast cancers with known metastatic sites. Conclusions: We conclude that T lymphocytes trigger cancer cells to express proteins including coronin-1A thereby facilitating their passage through an in vitro BBB. In addition, a prominent role of coronin-1A in the formation of cerebral metastases in breast cancer patients is strongly suggestive by its upregulation in tissue samples of breast cancer patients with brain metastases.
Project description:Estrogen Receptor subtypes (ERα and ERβ) are transcription factors sharing similar structure, however, they often perform opposite roles in breast cancer’s cell proliferation and tumor progression. Besides the well-characterized genomic actions of ERs upon ligand binding, rapid non-genomic cytoplasmic changes together with the recently discovered ligand-free action of ERs are emerging as key regulators of tumorigenesis. The identification of cytoplasmic interaction partners of unliganded ERα and ERβ may help characterize the molecular basis of the extra-nuclear mechanism of action of these receptors, revealing novel mechanisms to explain their role in breast cancer response or resistance to endocrine therapy. To this aim, in this study, cytoplasmic extracts from stably expressing TAP-ERα and -ERβ MCF-7 cell clones were subjected to interaction proteomics in the absence of estrogen stimulation, leading to the identification of 84 and 142 proteins associated with unliganded ERα and ERβ, respectively. Functional analyses of ER subtype-specific interactomes revealed significant differences in the molecular pathways associated to each receptor in the cytoplasm. This work reports the first identification of the unliganded ERα and ERβ cytoplasmic interactomes in breast cancer cells, providing novel experimental evidence on the non-genomic effects of ERs in the absence of hormonal stimulus.
Project description:Multiple-condition experiment was desinged to be any number of conditions in an experiment without replicate observations for microarray and used to identify genes differentially expressed between different pairs of conditions (treatments).<br> In this study we used breast cancer stable cell lines for overexpressing and silencing annexin A1 (ANXA1), which belongs to a family of -dependent phospholipid binding proteins and are preferentially located on the cytosolic face of the plasma membrane. Cell lines overexpressing ANXA1 (MDA_MB-453/cDNA) were generated by introducing retroviral vectors containing ANXA1 cDNA (pBabe/ANXA1 cDNA) into breast cancer cell line MDA-MB-453 (a low expressor of ANXA1). Breast cancer cell line BT-474, a high expressor of ANXA1, was infected with ANXA1 siRNA-plasmid viruses to knockdown ANAXAI expressor (BT-474/siRNA) where nucleotides corresponding to siRNA were synthesized and ligated into the pLNCX retroviral vector [35,36]. We also used a pLNCX/U6 empty vector to infect BT-474 and obtained an empty vector expressor. Therefore, 5 breast cancer cell lines (MDA_MB-453, MDA_MB-453/cDNA, BT-474, BT-474/siRNA, and BT-474/U6) are attributed to two genotypes: MDA_MB-453 and BT-474. MCE was performed for microarray analysis with these 5 breast cancer cell lines, that is, only one sample was drawn from each breast cancer cell line.
Project description:Here we obtained the proteotypes of 76 breast cancer cell lines using pressure cycling technology (PCT) and SWATH mass spectrometry.
Project description:Proteomic methods for disease state characterization and biomarker discovery have traditionally utilized quantitative mass spectrometry methods to identify proteins with altered expression levels in disease states. Here we report on the large-scale use of protein folding stability measurements to characterize different subtypes of breast cancer using the Stable Isotope Labeling with Amino Acids in Cell Culture and Stability of Proteins from Rates of Oxidation (SILAC-SPROX) technique. Protein folding stability differences were studied in a comparison of two luminal breast cancer subtypes, luminal-A and -B (i.e., MCF-7 and BT-474 cells, respectively), and in a comparison of a luminal-A and basal subtype of the disease (i.e., MCF-7 and MDA-MB-468 cells, respectively). The 242 and 445 protein hits identified with altered stabilities in these comparative analyses, included a large fraction with no significant expression level changes. This suggests thermodynamic stability measurements create a new avenue for protein biomarker discovery. A number of the identified protein hits are known from other biochemical studies to play a role in tumorigenesis and cancer progression. This not only substantiates the biological significance of the protein hits identified using the SILAC-SPROX approach, but it also helps elucidate the molecular basis for their dysregulation and/or dysfunction in cancer.
Project description:Introduction: Breast radiotherapy is currently â??one size fits allâ?? regardless of breast cancer subtype (eg. luminal, basal). However, recent clinical data suggests that radiation response may vary significantly among subtypes. Therefore, current practice leads to over- or under-treatment of women whose tumors are more or less radiation responsive. We hypothesized that this clinical variability may be due, in part, to differences in cellular radiation response. Methods: We exposed 16 biologically-diverse breast tumor cell lines to 0 or 5GY radiation. Microarray analysis was performed on RNA harvested from those cell lines. Samples were run in triplicate. Following quality assessment, differential gene expression analysis was performed using a two-way multiplicative linear mixed-effects model. A candidate radiation response biomarkers with biologically plausible role in radiation response, were identified and confirmed at the RNA and protein level with qPCR and Western blotting assays. Induction in human breast tumors was confirmed in 32 patients with paired pre- and post-radiation tumor samples using IHC and microarray analysis. Quantification of protein was performed in a blinded manner and included positive and negative controls. The objective of our study was to identify genomic determinants of radiation sensitivity using clinical samples as well as breast tumor cell lines. In order to identify differences in the radiation response gene expression profiles of specific breast cancer subtypes, we exposed 16 biologically-diverse breast tumor cell lines to 0 or 5GY radiation. Microarray analysis was performed on RNA harvested from those cell lines. Samples were run in triplicate. Following quality assessment, differential gene expression analysis was performed using a two-way multiplicative linear mixed-effects model. Candidate radiation response biomarker with a biologically plausible role in radiation response, were identified and confirmed at the RNA and protein level with qPCR and Western blotting assays. Induction of the genes of interest were further evaluated and confirmed in human breast tumors in 32 breast cancer patients with paired pre- and post-radiation tumor samples using IHC and microarray analysis assays.
Project description:Metastasis of breast cancer to other distant organs is fatal to patients. However, few studies have revealed biomarkers associated with distant metastatic breast cancer. Furthermore, the inability of current biomarkers such as HER2, ER and PR, in accurately differentiating between distant metastatic breast cancers from non-distant metastatic ones necessitates the development of novel biomarkers. An integrated proteomics approach that combines filter-aided sample preparation, tandem mass tag labeling (TMT), high pH fractionation, and high resolution MS was applied to acquire in-depth proteome data of distant metastatic breast cancer FFPE tissue. Bioinformatics analyses for gene ontology and signaling pathways using differentially expressed proteins (DEPs) were performed to investigate molecular characteristics of distant metastatic breast cancer. In addition, real-time polymerase chain reaction (RT-PCR) and invasion/migration assays were performed to validate the differential regulation and functional capability of biomarker candidates. A total of 9,459 and 8,760 proteins were identified from the pooled sample set and the individual sample set, respectively. Through our stringent criteria, TUBB2A was selected as a novel biomarker. The metastatic functions of the candidate were subsequently validated. Bioinformatics analysis using DEPs were able to characterize the overall molecular features of distant metastasis as well as investigate the differences across breast cancer subtypes. Our study is the first to explore the distant metastatic breast cancer proteome using FFPE tissue. The depth of our dataset enabled the discovery of novel biomarker and the investigation of proteomic characteristics of distant metastatic breast cancer. The distinct molecular features of breast cancer subtypes were also observed. Our proteomic data has important utility as a valuable resource for the research on distant metastatic breast cancer.
Project description:Conformational changes in proteins can lead to disease. Thus, methods for identifying conformational changes in proteins can further improve our understanding and facilitate detection of disease states. Here we combine limited proteolysis (LiP) with Stable Isotope Labeling with Amino Acids in Cell Culture (SILAC) to characterize breast cancer-related conformational changes in proteins on the proteomic scale. Studied here are the conformational properties of proteins in two cell culture models of breast cancer, including the MCF-10A and MCF-7 cell lines. The SILAC-LiP approach described here identified ~200 proteins with cell-line dependent conformational changes, as determined by their differential susceptibility to proteolytic digestion using the non-specific protease, proteinase K. The protease susceptibility profiles of the proteins in these cell lines were compared to thermodynamic stability and expression level profiles previously generated for proteins in these same breast cancer cell lines. The comparisons revealed that there was little overlap between the proteins with protease susceptibility changes and the proteins with thermodynamic stability and/or expression level changes. Thus, the large-scale conformational analysis described here provides unique insight into the molecular basis of the breast cancer phenotypes in this study.
Project description:We sought to build a catalog of epitopes presented by breast cancers using a renewable resource of well-characterized breast cancer cell lines. Starting from 70 breast cancer cell lines, we measured MHC class I abundance and used pre-existing RNAseq data to identify either HLA-A*02 or MHC class I-positive cell lines. For 20 of these cell lines, we used “reverse” immunogenetics, in which MHC class I-loaded peptides are recovered and their sequences are determined by mass spectrometry. We identified more than 2,700 unique MHC class I-bound peptides from a panel of basal, luminal, and claudin-low subtype of cell lines. HLA-A*02 binding prediction across all tested cell lines revealed a model which described the distribution of HLA-A*02-binding peptides and allowed us to identify those peptides most likely to be presented on HLA-A*02. Comparing the peptides that we identified to published literature found that more than 1500 peptides had been identified in previous studies and that 18 of these peptides have been shown to be immunogenic. Overall, this high throughput identification of MHC class I-loaded peptides is an effective strategy for systematic characterization of cancer epitopes and could be employed in a design of multipeptide-based anticancer vaccine.