Arsenic alters global histone modifications in lymphocytes in vitro and in vivo.

Arsenic, an established carcinogen and toxicant, occurs in drinking water and food and affects millions of people worldwide. Arsenic appears to interfere with gene expression through epigenetic processes, such as DNA methylation and post-translational histone modifications. We investigated the effects of arsenic on histone residues in vivo as well as in vitro. Analysis of H3K9Ac and H3K9me3 in CD4+ and CD8+ sorted blood cells from individuals exposed to arsenic through drinking water in the Argentinean Andes showed a significant decrease in global H3K9me3 in CD4+ cells, but not CD8+ cells, with increasing arsenic exposure. In vitro studies of inorganic arsenic-treated T lymphocytes (Jurkat and CCRF-CEM, 0.1, 1, and 100 µg/L) showed arsenic-related modifications of H3K9Ac and changes in the levels of the histone deacetylating enzyme HDAC2 at very low arsenic concentrations. Further, in vitro exposure of kidney HEK293 cells to arsenic (1 and 5 µM) altered the protein levels of PCNA and DNMT1, parts of a gene expression repressor complex, as well as MAML1. MAML1 co-localized and interacted with components of this complex in HEK293 cells, and in silico studies indicated that MAML1 expression correlate with HDAC2 and DNMT1 expression in kidney cells. In conclusion, our data suggest that arsenic exposure may lead to changes in the global levels of H3K9me3 and H3K9Ac in lymphocytes. Also, we show that arsenic exposure affects the expression of PCNA and DNMT1-proteins that are part of a gene expression silencing complex.

Toward the Replacement of Animal Experiments through the Bioinformatics-driven Analysis of 'Omics' Data from Human Cell Cultures.

This paper outlines the work for which Roland Grafström and Pekka Kohonen were awarded the 2014 Lush Science Prize. The research activities of the Grafström laboratory have, for many years, covered cancer biology studies, as well as the development and application of toxicity-predictive in vitro models to determine chemical safety. Through the integration of in silico analyses of diverse types of genomics data (transcriptomic and proteomic), their efforts have proved to fit well into the recently-developed Adverse Outcome Pathway paradigm. Genomics analysis within state-of-the-art cancer biology research and Toxicology in the 21st Century concepts share many technological tools. A key category within the Three Rs paradigm is the Replacement of animals in toxicity testing with alternative methods, such as bioinformatics-driven analyses of data obtained from human cell cultures exposed to diverse toxicants. This work was recently expanded within the pan-European SEURAT-1 project (Safety Evaluation Ultimately Replacing Animal Testing), to replace repeat-dose toxicity testing with data-rich analyses of sophisticated cell culture models. The aims and objectives of the SEURAT project have been to guide the application, analysis, interpretation and storage of 'omics' technology-derived data within the service-oriented sub-project, ToxBank. Particularly addressing the Lush Science Prize focus on the relevance of toxicity pathways, a 'data warehouse' that is under continuous expansion, coupled with the development of novel data storage and management methods for toxicology, serve to address data integration across multiple 'omics' technologies. The prize winners' guiding principles and concepts for modern knowledge management of toxicological data are summarised. The translation of basic discovery results ranged from chemical-testing and material-testing data, to information relevant to human health and environmental safety.

Requirement of apoptotic protease-activating factor-1 for bortezomib-induced apoptosis but not for Fas-mediated apoptosis in human leukemic cells.

Bortezomib is a highly selective inhibitor of the 26S proteasome and has been approved for clinical use in the treatment of relapsing and refractory multiple myeloma and mantle cell lymphoma. Clinical trials are also underway to assess the role of bortezomib in several other human malignancies, including leukemia. However, the mechanism(s) by which bortezomib acts remain to be fully understood. Here, we studied the molecular requirements of bortezomib-induced apoptosis using the human T-cell leukemic Jurkat cells stably transfected with or without shRNA against apoptotic protease-activating factor-1 (Apaf-1). The Apaf-1-deficient Jurkat T cells were resistant to bortezomib-induced apoptosis, as assessed by caspase-3 activity, poly(ADP-ribose) polymerase cleavage, phosphatidylserine externalization, and hypodiploid DNA content. In contrast, Apaf-1-deficient cells were sensitive to Fas-induced apoptosis. Bortezomib induced an upregulation of the pro-apoptotic protein Noxa, loss of mitochondrial transmembrane potential, and release of cytochrome c in cells expressing or not expressing Apaf-1. Transient silencing of Apaf-1 expression in RPMI 8402 T-cell leukemic cells also diminished bortezomib-induced apoptosis. Fas-associated death domain (FADD)-deficient Jurkat cells were resistant to Fas-mediated apoptosis yet remained sensitive to bortezomib. Our results show that bortezomib induces apoptosis by regulating pathways that are mechanistically different from those activated upon death receptor ligation. Furthermore, in silico analyses of public transcriptomics databases indicated elevated Apaf-1 expression in several hematologic malignancies, including acute lymphoblastic and myeloid leukemia. We also noted variable Apaf-1 expression in a panel of samples from patients with acute lymphoblastic leukemia. Our results suggest that the expression of Apaf-1 may be predictive of the response to proteasome inhibition.

Differentiation-promoting culture of competent and noncompetent keratinocytes identifies biomarkers for head and neck cancer.

Aberrant contact-inhibited proliferation and differentiation induction couple with tumor severity, albeit with an imprecise association with prognosis. Assessment of contact inhibition and differentiation-promoting culture in this study of normal and immortalized oral keratinocytes (NOK and SVpgC2a, respectively) demonstrated elevated cloning ability and saturation density in the immortalized versus normal state, including consistent absence of differentiated morphological features. Transcriptomic analysis implicated 48 gene ontology categories, 8 molecular networks, and 10 key regulator genes in confluency-induced differentiation of NOK, all of which remained nonregulated in SVpgC2a. The SVpgC2a versus NOK transcriptome enriched 52 gene ontology categories altogether, 18 molecular networks, and 39 key regulator genes, several of which were associated with epithelial-mesenchymal transition. Assessment of the previously described gene sets relative to training data sets of head and neck squamous cell carcinoma samples, one including data on tumor differentiation and patient outcome and one present in the Human Gene Expression Map, identified four genes with association to poor survival (COX7A1, MFAP5, MPDU1, and POLD1). This gene set predicted poor outcome in an independent data set of 71 head and neck squamous cell carcinomas. The present study defines, for the first time to our knowledge, the broad gene spectrum that couples to induction, and loss, of oral keratinocyte differentiation. Bioinformatics assessments of the results relative to clinical data generated novel differentiation-related tumor biomarkers relevant to patient outcome.

Combining factors on protein and gene level to predict radioresponse in head and neck cancer cell lines.

BACKGROUND: Radiotherapy is the main therapy for head and neck squamous cell carcinoma (HNSCC); however, treatment resistance and local recurrence are significant problems, highlighting the need for predictive markers. In this study, we evaluated selected proteins, mutations, and single nucleotide polymorphisms (SNPs) involved in apoptosis, cell proliferation, and DNA repair alone or combined as predictive markers for radioresponse in 42 HNSCC cell lines. METHODS: The expression of epidermal growth factor receptor, survivin, Bax, Bcl-2, Bcl-X(L) , cyclooxygenase-2 (COX-2), and heat shock protein 70 was analyzed by ELISA. Furthermore, mutations and SNPs in the p53 gene as well as SNPs in the MDM2, XRCC1, and XRCC3 genes were analyzed for their relation to radioresponse. To enable the evaluation of the predictive value of several factors combined, each cell line was allocated points based on the number of negative points (NNP) system, and the NNP sum was correlated with radioresponse. RESULTS: Survivin was the only factor that alone was significantly correlated with the intrinsic radiosensitivity (IR; r = 0.36, P = 0.02). The combination of survivin, Bax, Bcl-2, Bcl-X(L) , COX-2, and the p53 Arg72Pro polymorphism was found to most strongly correlate with radioresponse (r = 0.553, P < 0.001). CONCLUSION: These data indicate that the IR of 42 HNSCC cell lines can be predicted by a panel of factors on both the protein and gene levels. Moreover, among the investigated factors, survivin was the most promising biomarker of radioresponse.

Multiple genotypic aberrances associate to terminal differentiation-deficiency of an oral squamous cell carcinoma in serum-free culture.

Oral squamous cell carcinoma (OSCC) lines proliferative in the serum-free conditions devised for normal oral keratinocytes (NOK) are virtually absent, complicating studies of carcinogenesis. A tongue squamous cell carcinoma generated under conditions for normal cell culture an apparently immortal line (termed LK0412) that has undergone >or=200 population doublings from over a year in culture. LK0412 exhibited epithelial morphology, intermediate filaments, desmosomes, and cytokeratin. Soft agar growth and tumorigenicity in athymic nude mice indicated the malignant phenotype. Compared with NOK, LK0412 exhibited increased indices for proliferation and apoptosis, and a decreased terminal differentiation index. Fetal bovine serum inhibited growth and increased apoptosis but failed to induce terminal differentiation of LK0412; the latter outcome differed clearly from that in NOK. Gene ontology assessment of transcript profiles implicated multiple alterations in biological processes, molecular functions, and cellular components in LK0412. Genetic changes, some that were confirmed to the protein level, included previously proposed OSCC markers, i.e., BAX, CDC2, and TP53, as well as multiple cancer-associated genes not considered for OSCC, e.g., BST2, CRIP1, ISG15, KLRC1, NEDD9, NNMT, and TWIST1. Elevation of p53 protein agreed with a missense mutation detectable in both the LK0412 line and the original tumor specimen. Moderate differentiation characterized the original tumor as well as tumors generated from inoculation of LK0412 in mice. Overall, the results suggest that the LK0412 cell line represent a subgroup of OSCC with unique genomic and phenotypic profiles. LK0412 should be useful to exploration of OSCC development, particularly the deregulated growth and differentiation responsiveness to serum factors.

Properties and units in the clinical laboratory sciences part XXIV. Properties and units in clinical molecular genetics (technical report 2017).

This document describes the application of the syntax, semantic rules, and format of the Nomenclature for Properties and Units (NPU) terminology for coded dedicated kinds-of-property in the subject field of clinical molecular genetics. A vocabulary for NPU definitions in this field, based on international terminology and nomenclature, is introduced; examples of actual NPU definitions for different types of investigations are given and explained.

The application of normal, SV40 T-antigen-immortalised and tumour-derived oral keratinocytes, under serum-free conditions, to the study of the probability of cancer progression as a result of environmental exposure to chemicals.

In vitro models are currently not considered to be suitable replacements for animals in experiments to assess the multiple factors that underlie the development of cancer as a result of environmental exposure to chemicals. An evaluation was conducted on the potential use of normal keratinocytes, the SV40 T-antigen-immortalised keratinocyte cell line, SVpgC2a, and the carcinoma cell line, SqCC/Y1, alone and in combination, and under standardised serum-free culture conditions, to study oral cancer progression. In addition, features considered to be central to cancer development as a result of environmental exposure to chemicals, were analysed. Genomic expression, and enzymatic and functional data from the cell lines reflected many aspects of the transition of normal tissue epithelium, via dysplasia, to full malignancy. The composite cell line model develops aberrances in proliferation, terminal differentiation and apoptosis, in a similar manner to oral cancer progression in vivo. Transcript and protein profiling links aberrations in multiple gene ontologies, molecular networks and tumour biomarker genes (some proposed previously, and some new) in oral carcinoma development. Typical specific changes include the loss of tumour-suppressor p53 function and of sensitivity to retinoids. Environmental agents associated with the aetiology of oral cancer differ in their requirements for metabolic activation, and cause toxic effects to cells in both the normal and the transformed states. The results suggest that the model might be useful for studies on the sensitivity of cells to chemicals at different stages of cancer progression, including many aspects of the integrated roles of cytotoxicity and genotoxicity. Overall, the properties of the SVpgC2a and SqCC/Y1 cell lines, relative to normal epithelial cells in monolayer or organotypic culture, support their potential applicability to mechanistic studies on cancer risk factors, including, in particular, the definition of critical toxicity effects and dose-effect relationships.

A transcriptomics data-driven gene space accurately predicts liver cytopathology and drug-induced liver injury.

Predicting unanticipated harmful effects of chemicals and drug molecules is a difficult and costly task. Here we utilize a 'big data compacting and data fusion'-concept to capture diverse adverse outcomes on cellular and organismal levels. The approach generates from transcriptomics data set a 'predictive toxicogenomics space' (PTGS) tool composed of 1,331 genes distributed over 14 overlapping cytotoxicity-related gene space components. Involving ∼2.5 × 108 data points and 1,300 compounds to construct and validate the PTGS, the tool serves to: explain dose-dependent cytotoxicity effects, provide a virtual cytotoxicity probability estimate intrinsic to omics data, predict chemically-induced pathological states in liver resulting from repeated dosing of rats, and furthermore, predict human drug-induced liver injury (DILI) from hepatocyte experiments. Analysing 68 DILI-annotated drugs, the PTGS tool outperforms and complements existing tests, leading to a hereto-unseen level of DILI prediction accuracy.

Cancer biology, toxicology and alternative methods development go hand-in-hand.

Toxicological research faces the challenge of integrating knowledge from diverse fields and novel technological developments generally in the biological and medical sciences. We discuss herein the fact that the multiple facets of cancer research, including discovery related to mechanisms, treatment and diagnosis, overlap many up and coming interest areas in toxicology, including the need for improved methods and analysis tools. Common to both disciplines, in vitro and in silico methods serve as alternative investigation routes to animal studies. Knowledge on cancer development helps in understanding the relevance of chemical toxicity studies in cell models, and many bioinformatics-based cancer biomarker discovery tools are also applicable to computational toxicology. Robotics-aided, cell-based, high-throughput screening, microscale immunostaining techniques and gene expression profiling analyses are common tools in cancer research, and when sequentially combined, form a tiered approach to structured safety evaluation of thousands of environmental agents, novel chemicals or engineered nanomaterials. Comprehensive tumour data collections in databases have been translated into clinically useful data, and this concept serves as template for computer-driven evaluation of toxicity data into meaningful results. Future 'cancer research-inspired knowledge management' of toxicological data will aid the translation of basic discovery results and chemicals- and materials-testing data to information relevant to human health and environmental safety.

YAP1 is a potential biomarker for cetuximab resistance in head and neck cancer.

OBJECTIVES: Targeted therapy against the epidermal growth factor receptor (EGFR) only variably represents a therapeutic advance in head and neck squamous cell carcinoma (HNSCC). This study addresses the need of biomarkers of treatment response to the EGFR-targeting antibody cetuximab (Erbitux®). MATERIALS AND METHODS: The intrinsic cetuximab sensitivity of HNSCC cell lines was assessed by a crystal violet assay. Gene copy number analysis of five resistant and five sensitive cell lines was performed using the Affymetrix SNP 6.0 platform. Quantitative real-time PCR was used for verification of selected copy number alterations and assessment of mRNA expression. The functional importance of the findings on the gene and mRNA level was investigated employing siRNA technology. The data was statistically evaluated using Mann-Whitney U-test and Spearman's correlation test. RESULTS: Analysis of the intrinsic cetuximab sensitivity of 32 HNSCC cell lines characterized five and nine lines as cetuximab sensitive or resistant, respectively. Gene copy number analysis of five resistant versus five sensitive cell lines identified 39 amplified protein-coding genes, including YAP1, in the genomic regions 11q22.1 or 5p13-15. Assessment using qPCR verified that YAP1 amplification associated with cetuximab resistance. Amplification of YAP1 correlated to higher mRNA levels, and RNA knockdown resulted in increased cetuximab sensitivity. Assessment of several independent clinical data sets in the public domain confirmed YAP1 amplifications in multiple tumor types including HNSCC, along with highly differential expression in a subset of HNSCC patients. CONCLUSION: Taken together, we provide evidence that YAP1 could represent a novel biomarker gene of cetuximab resistance in HNSCC cell lines.

The ToxBank Data Warehouse: Supporting the Replacement of In Vivo Repeated Dose Systemic Toxicity Testing.

The aim of the SEURAT-1 (Safety Evaluation Ultimately Replacing Animal Testing-1) research cluster, comprised of seven EU FP7 Health projects co-financed by Cosmetics Europe, is to generate a proof-of-concept to show how the latest technologies, systems toxicology and toxicogenomics can be combined to deliver a test replacement for repeated dose systemic toxicity testing on animals. The SEURAT-1 strategy is to adopt a mode-of-action framework to describe repeated dose toxicity, combining in vitro and in silico methods to derive predictions of in vivo toxicity responses. ToxBank is the cross-cluster infrastructure project whose activities include the development of a data warehouse to provide a web-accessible shared repository of research data and protocols, a physical compounds repository, reference or "gold compounds" for use across the cluster (available via wiki.toxbank.net), and a reference resource for biomaterials. Core technologies used in the data warehouse include the ISA-Tab universal data exchange format, REpresentational State Transfer (REST) web services, the W3C Resource Description Framework (RDF) and the OpenTox standards. We describe the design of the data warehouse based on cluster requirements, the implementation based on open standards, and finally the underlying concepts and initial results of a data analysis utilizing public data related to the gold compounds.

CD44 expression in oro-pharyngeal carcinoma tissues and cell lines.

Expression of CD44, a transmembrane hyaluronan-binding glycoprotein, is variably considered to have prognostic significance for different cancers, including oral squamous cell carcinoma. Although unclear at present, tissue-specific expression of particular isoforms of CD44 might underlie the different outcomes in currently available studies. We mined public transcriptomics databases for gene expression data on CD44, and analyzed normal, immortalized and tumour-derived human cell lines for splice variants of CD44 at both the transcript and protein levels. Bioinformatics readouts, from a total of more than 15,000 analyses, implied an increased CD44 expression in head and neck cancer, including increased expression levels relative to many normal and tumor tissue types. Also, meta-analysis of over 260 cell lines and over 4,000 tissue specimens of diverse origins indicated lower CD44 expression levels in cell lines compared to tissue. With minor exceptions, reverse transcribed polymerase chain reaction identified expression of the four main isoforms of CD44 in normal oral keratinocytes, transformed lines termed DT and HaCaT, and a series of paired primary and metastasis-derived cell lines from oral or pharyngeal carcinomas termed HN4/HN12, HN22/HN8 and HN30/HN31. Immunocytochemistry, Western blotting and flow cytometric assessments all confirmed the isoform expression pattern at the protein level. Overall, bioinformatic processing of large numbers of global gene expression analyses demonstrated elevated CD44 expression in head and neck cancer relative to other cancer types, and that the application of standard cell culture protocols might decrease CD44 expression. Additionally, the results show that the many variant CD44 exons are not fundamentally deregulated in a diverse range of cultured normal and transformed keratinocyte lines.

MAML1 acts cooperatively with EGR1 to activate EGR1-regulated promoters: implications for nephrogenesis and the development of renal cancer.

Mastermind-like 1 (MAML1) is a transcriptional coregulator of activators in various signaling pathways, such as Notch, p53, myocyte enhancer factor 2C (MEF2C) and beta-catenin. In earlier studies, we demonstrated that MAML1 enhanced p300 acetyltransferase activity, which increased the acetylation of Notch by p300. In this study, we show that MAML1 strongly induced acetylation of the transcription factor early growth response-1 (EGR1) by p300, and increased EGR1 protein expression in embryonic kidney cells. EGR1 mRNA transcripts were also upregulated in the presence of MAML1. We show that MAML1 physically interacted with, and acted cooperatively with EGR1 to increase transcriptional activity of the EGR1 and p300 promoters, which both contain EGR1 binding sites. Bioinformatics assessment revealed a correlation between p300, EGR1 and MAML1 copy number and mRNA alterations in renal clear cell carcinoma and p300, EGR1 and MAML1 gene alterations were associated with increased overall survival. Our findings suggest MAML1 may be a component of the transcriptional networks which regulate EGR1 target genes during nephrogenesis and could also have implications for the development of renal cell carcinoma.

Formaldehyde dehydrogenase: beyond phase I metabolism.

Formaldehyde dehydrogenase, formally Class III alcohol dehydrogenase (ADH3), has recently been discovered to partially regulate nitrosothiol homeostasis by catalyzing the reduction of the endogenous nitrosylating agent S-nitrosoglutathione (GSNO). Several studies have implicated this enzyme, and in particular GSNO reduction, as playing an important role in conditions such as asthma, cardiovascular disease, and immune function. While ADH3 has received considerable attention in the biomedical literature where it is often referred to as GSNO reductase (GSNOR), ADH3-mediated GSNO reduction has received comparatively less attention in the environmental toxicology community. Herein, evidences for a role of ADH3 in cell signaling through thiol homeostasis is highlighted, underscoring that the enzyme functions more broadly than to metabolize formaldehyde.

Fibronectin 1 is a potential biomarker for radioresistance in head and neck squamous cell carcinoma.

Radiotherapy remains the backbone of head and neck cancer therapy but response is sometimes impeded by tumor radioresistance. Identifying predictive biomarkers of radiotherapy response is a crucial step towards personalized therapy. The aim of this study was to explore gene expression data in search of biomarkers predictive of the response to radiotherapy in head and neck squamous cell carcinoma (HNSCC). Microarray analysis was performed on five cell lines with various intrinsic radiosensitivity, selected from a panel of 29 HNSCC cell lines. The bioinformatics approach included Gene Ontology (GO) enrichment profiling and Ingenuity Pathway Analysis (IPA). The GO-analysis detected 16 deregulated categories from which development, receptor activity, and extracellular region represented the largest groups. Fourteen hub genes (CEBPA, CEBPB, CTNNB1, FN1, MYC, MYCN, PLAU, SDC4, SERPINE1, SP1, TAF4B, THBS1, TP53 and VLDLR) were identified from the IPA network analysis. The hub genes in the highest ranked network, (FN1, SERPINE1, THBS1 and VLDLR) were further subjected to qPCR analysis in the complete panel of 29 cell lines. Of these genes, high FN1 expression associated to high intrinsic radiosensitivity (p=0.047). In conclusion, gene ontologies and hub genes of importance for intrinsic radiosensitivity were defined. The overall results suggest that FN1 should be explored as a potential novel biomarker for radioresistance.

Matrix metalloproteinase-7 and -13 expression associate to cisplatin resistance in head and neck cancer cell lines.

Concomitant chemoradiotherapy is a common treatment for advanced head and neck squamous cell carcinomas (HNSCC). Cisplatin is the backbone of chemotherapy regimens used to treat HNSCC. Therefore, the aim of this study was to identify predictive markers for cisplatin treatment outcome in HNSCC. The intrinsic cisplatin sensitivity (ICS) was determined in a panel of tumour cell lines. From this panel, one sensitive and two resistant cell lines were selected for comparative transcript profiling using microarray analysis. The enrichment of Gene Ontology (GO) categories in sensitive versus resistant cell lines were assessed using the Gene Ontology Tree Machine bioinformatics tool. In total, 781 transcripts were found to be differentially expressed and 11 GO categories were enriched. Transcripts contributing to this enrichment were further analyzed using Ingenuity Pathway Analysis (IPA) for identification of key regulator genes. IPA recognized 20 key regulator genes of which five were differentially expressed in sensitive versus resistant cell lines. The mRNA level of these five genes was further assessed in a panel of 25 HNSCC cell lines using quantitative real-time PCR. Among these key regulators, MMP-7 and MMP-13 are implicated as potential biomarkers of ICS. Taken together, genome-wide transcriptional analysis identified single genes, GO categories as well as molecular networks that are differentially expressed in HNSCC cell lines with different ICS. Furthermore, two novel predictive biomarkers for cisplatin resistance, MMP-7 and MMP-13, were identified.

Bioinformatics processing of protein and transcript profiles of normal and transformed cell lines indicates functional impairment of transcriptional regulators in buccal carcinoma.

Normal and two transformed buccal keratinocyte lines were cultured under a standardized condition to explore mechanisms of carcinogenesis and tumor marker expression at transcript and protein levels. An approach combining three bioinformatic programs allowed coupling of abundant proteins and large-scale transcript data to low-abundance transcriptional regulators. The analysis identified previously proposed and suggested novel protein biomarkers, gene ontology categories, molecular networks, and functionally impaired key regulator genes for buccal/oral carcinoma.