Project description:Protein O-mannosyltransferases (PMTs) are conserved endoplasmic reticulum membrane embedded enzymes responsible for the transfer of mannose from dolichol phosphate-mannose (Dol-P-Man) to serine/threonine-rich protein substrates or unfolded proteins. PMTs from three subfamilies form obligate dimers with different substrate specificities, and require the concerted action of their transmembrane domains (TMDs) and a luminal MIR domain for catalysis. Here, we present structures, native mass spectrometry and structure-based mutagenesis of the Chaetomium thermophilum and Saccharomyces cerevisiae Pmt4 homodimers. The core fold of the TMDs and MIR domain is conserved with the Pmt1-Pmt2 heterodimer, indicating a shared catalytic mechanism. Distinct to Pmt4, the MIR domain interacts in cis with the TMDs of the same subunit and has a beta-hairpin insertion required for O-mannosylation of substrates. We further identify a cytosolic binding site for substrate Dol33 P-Man within the Pmt4 TMDs, which is conserved amongst PMTs and important for in vivo activity. Thus, we provide a framework to understand the substrate specificity and regulation of the Pmt4 homodimer.
Project description:MicroRNAs are important negative regulators of protein coding gene expression, and have been studied intensively over the last few years. To this purpose, different measurement platforms to determine their RNA abundance levels in biological samples have been developed. In this study, we have systematically compared 12 commercially available microRNA expression platforms by measuring an identical set of 20 standardized positive and negative control samples, including human universal reference RNA, human brain RNA and titrations thereof, human serum samples, and synthetic spikes from homologous microRNA family members. We developed novel quality metrics in order to objectively assess platform performance of very different technologies such as small RNA sequencing, RT-qPCR and (microarray) hybridization. We assessed reproducibility, sensitivity, quantitative performance, and specificity. The results indicate that each method has its strengths and weaknesses, which helps guiding informed selection of a quantitative microRNA gene expression platform in function of particular study goals.
Project description:Aim of this study is to unveil the global transcriptomic expression levels upon Knockout of Snai1 in triple negative breast cancer cells Hs578T.
Project description:Aim of this study is to unveil the global transcriptomic expression levels upon Knockout of ZEB1 in triple negative breast cancer cells Hs578T.
Project description:Introducing a clinical-practical, alternative splicing activity-based proteogenomic method that identifies, in their oncogenically active states, biomarker genes bearing patient-specific GE or copy-number alterations of prognostic significance. This integrated multi-omics method uses intronic splicing enhancers (ISEs) probes to sort in situ ISE-interacting trans-acting protein factors (trans-interactome) directly from a heterogeneous tumor for subsequent mass spectrometry (MS) characterization.
Project description:It has been suggested that breast cancers are driven and maintained by a cellular subpopulation with stem cell properties. These breast cancer stem cells (BCSCs) mediate metastasis and by virtue of their resistance to radiation and chemotherapy, contribute to relapse. Although several BCSC markers have been described, it is unclear whether these markers identify the same or independent BCSC populations. Based on established breast cancer cell lines, as well as primary tumor samples and xenografts, we show that BCSCs exist in distinct mesenchymal-like (epithelial-mesenchymal transition, EMT) and epithelial-like (mesenchymal-epithelial transition, MET) states characterized by expression of distinct markers, proliferative capacity and invasive characteristics. The gene expression profiles of mesenchymal-like and epithelial-like BCSCs are remarkably similar across the different molecular subtypes of breast cancer and resemble those of distinct basal and luminal stem cells found in the normal breast. We propose that the plasticity of BCSCs allowing them to transition between EMT- and MET-like states endows these cells with the capacity for tissue invasion, dissemination and growth at metastatic sites. Breast cancer cells from patient were sorted using flow cytometry to select for cells that were ALDH+. Gene expression profiles of these cells were compared with profiles of ALDH- cells.
Project description:Cancer-associated fibroblasts (CAFs) have been recognized as important contributors to cancer development and progression. However, opposing evidence has been published whether CAFs, in addition to epigenetic, also undergo somatic genetic alterations and whether these changes contribute to carcinogenesis and tumour progression. We combined multiparameter DNA flow cytometry, flow-sorting and 6K SNP-arrays to study DNA aneuploidy, % S-phase, loss of heterozygosity (LOH) and copy number alterations (CNAs) to study somatic genetic alterations in cervical cancer-associated stromal cell fractions (n = 58) from formalin-fixed, paraffin-embedded (FFPE) samples. Tissue sections were examined for the presence of CAFs. Microsatellite analysis was used to study LOH. By flow cytometry we found no proof for DNA aneuploidy in the vimentin-positive stromal cell fractions of any samples (CV G0G1 population 3.7% +/- 1.2; S-phase 1.4% +/- 1.8). The genotype concordance between the stromal cells and the paired normal endometrium samples was > 99.9%. No evidence for CNAs or LOH was found in the stromal cell fractions. In contrast, high frequencies of DNA content abnormalities (43/57), a significant higher S-phase (14.6% +/- 8.5)(p = 0.0001) and substantial numbers of CNAs and LOH were identified in the keratin-positive epithelial cell fractions (CV G0G1 population 4.1% +/- 1.0). Smooth muscle actin and vimentin immunohistochemistry verified the presence of CAFs in all cases tested. LOH hot-spots on chromosomes 3p, 4p and 6p were confirmed by microsatellite analysis but the stromal cell fractions showed retention of heterozygosity only. From our study we conclude that stromal cell fractions from cervical carcinomas are DNA diploid, have a genotype undistinguishable from patient-matched normal tissue and are genetically stable. Stromal genetic changes do not seem to play a role during cervical carcinogenesis and progression. In addition, the stromal cell fraction of cervical carcinomas can be used as reference allowing large retrospective studies of archival FFPE tissues for which no normal reference tissue is available. Paired experiment, Endometrial (non-tumor) cells vs stromal cells from cervical tumors. Biological replicates: 58 patients. From 5 tumors also the tumor fraction was profiled.
Project description:Recurrent non-medullary thyroid carcinoma (NMTC) is a rare disease. We initially characterized 27 recurrent NMTC: 13 papillary thyroid cancers (PTC), 10 oncocytic follicular carcinomas (FTC-OV), and 4 non-oncocytic follicular carcinomas (FTC). A validation cohort composed of benign and malignant (both recurrent and non-recurrent) thyroid tumours was subsequently analysed (n = 20). Methods Data from genome-wide SNP arrays and flow cytometry were combined to determine the chromosomal dosage (allelic state) in these tumours, including mutation analysis of components of PIK3CA/AKT and MAPK pathways. Results All FTC-OVs showed a very distinct pattern of genomic alterations. Ten out of 10 FTC-OV cases showed near-haploidisation with or without subsequent genome endoreduplication. Near-haploidisation was seen in 5/10 as extensive chromosome-wide monosomy (allelic state [A]) with near-haploid DNA indices and retention of especially chromosome 7 (seen as a heterozygous allelic state [AB]). In the remaining 5/10 chromosomal allelic states AA with near diploid DNA indices were seen with allelic state AABB of chromosome 7, suggesting endoreduplication after preceding haploidisation. The latter was supported by the presence of both near-haploid and endoreduplicated tumour fractions in some of the cases. Results were confirmed using FISH analysis. Relatively to FTC-OV limited numbers of genomic alterations were identified in other types of recurrent NMTC studied, except for chromosome 22q which showed alterations in 6 of 13 PTCs. Only two HRAS, but no mutations of EGFR or BRAF were found in FTC-OV. The validation cohort showed two additional tumours with the distinct pattern of genomic alterations (both with oncocytic features and recurrent). Conclusions We demonstrate that recurrent FTC-OV is frequently characterised by genome-wide DNA haploidisation, heterozygous retention of chromosome 7, and endoreduplication of a near-haploid genome. Whether normal gene dosage on especially chromosome 7 (containing EGFR, BRAF, cMET) is crucial for FTC-OV tumour survival is an important topic for future research. 28 thyroid tumors from 27 patients were profiled by SNP array. Comparisons between different types were made.
Project description:Estrogens receptor a (ERα) is essential for breast tumors,since about seventy percent of breast cancers are detected as ERα positive.Recent studies suggest that ERα is related with the epithelial cell morphology. Recently, it has demonstrated that the suppression of ERα induced epithelial-mesenchymal transition (EMT) in the MCF-7 breast cacner cells. Interestingly, the loss of ERa resulted in strong differences on the gene expression profile of a variety of genes. Therefore, the aim of the RNA-seq is to elucidate the effect of the silencing of ERα on the mRNA levels of a larger variety of genes, thus revealing possible target genes which may be implicated on the aggressive phenotype and behavior of the ERα-suppresed MCF-7/SP10+ breast cancer cells. For this reason total RNA from both MCF-7/SP10+ cells and of their internal control MCF-7/C cells was extracted in 3 biological replicates and 3 technical replicates.