Molecular portrait of cisplatin induced response in human testis cancer cell lines based on gene expression profiles

Abstract Background Testicular germ cell tumors (TGCTs) respond well to cisplatin-based chemotherapy and show a low incidence of acquired resistance compared to most somatic tumors. The reasons for these specific characteristics are not known in detail but seem to be multifactorial. We have studied gene expression profiles of testicular and colon cancer derived cell lines treated with cisplatin. The main goal of this study was to identify novel gene expression profiles with their functional categories and the biochemical pathways that are associated with TGCT cells' response to cisplatin. Results Genes that were differentially expressed between the TGCT cell lines vs the (somatic) HCT116 cell line, after cisplatin treatment, were identified using the significance analysis of microarrays (SAM) method. The response of TGCT cells was strikingly different from that of HCT116, and we identified 1794 genes that were differentially expressed. Functional classification of these genes showed that they participate in a variety of different and widely distributed functional categories and biochemical pathways. Database mining showed significant association of genes (n = 41) induced by cisplatin in our study, and genes previously reported to by expressed in differentiated TGCT cells. We identified 37 p53-responsive genes that were altered after cisplatin exposure. We also identified 40 target genes for two microRNAs, hsa-mir-372 and 373 that may interfere with p53 signaling in TGCTs. The tumor suppressor genes NEO1 and LATS2, and the estrogen receptor gene ESR1, all have binding sites for p53 and hsa-mir-372/373. NEO1 and LATS2 were down-regulated in TGCT cells following cisplatin exposure, while ESR1 was up-regulated in TGCT cells. Cisplatin-induced genes associated with terminal growth arrest through senescence were identified, indicating associations which were not previously described for TGCT cells. Conclusion By linking our gene expression data to publicly available databases and literature, we provide a global pattern of cisplatin induced cellular response that is specific for testicular cancer cell lines. We have identified cisplatin-responsive functional classes and pathways, such as the angiogenesis, Wnt, integrin, and cadherin signaling pathways. The identification of differentially expressed genes in this study may contribute to a better understanding of the unusual sensitivity of TGCT to some DNA-damaging agents.</p

Dose rate-driven responses to ionizing radiation in CBA/Ca and C57BL/6N evaluated using benchmark dose (BMD) modeling

publishedVersio

Dose rate dependent reduction in chromatin accessibility at transcriptional start sites long time after exposure to gamma radiation

Ionizing radiation (IR) impact cellular and molecular processes that require chromatin remodelling relevant for cellular integrity. However, the cellular implications of ionizing radiation (IR) delivered per time unit (dose rate) are still debated. This study investigates whether the dose rate is relevant for inflicting changes to the epigenome, represented by chromatin accessibility, or whether it is the total dose that is decisive. CBA/CaOlaHsd mice were whole-body exposed to either chronic low dose rate (2.5 mGy/h for 54 d) or the higher dose rates (10 mGy/h for 14 d and 100 mGy/h for 30 h) of gamma radiation (60Co, total dose: 3 Gy). Chromatin accessibility was analysed in liver tissue samples using Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-Seq), both one day after and over three months post-radiation (>100 d). The results show that the dose rate contributes to radiation-induced epigenomic changes in the liver at both sampling timepoints. Interestingly, chronic low dose rate exposure to a high total dose (3 Gy) did not inflict long-term changes to the epigenome. In contrast to the acute high dose rate given to the same total dose, reduced accessibility at transcriptional start sites (TSS) was identified in genes relevant for the DNA damage response and transcriptional activity. Our findings link dose rate to essential biological mechanisms that could be relevant for understanding long-term changes after ionizing radiation exposure. However, future studies are needed to comprehend the biological consequence of these findings.publishedVersio

Risk assessment of grilled and barbecued food

When grilling, more harmful substances can be formed than when frying in a pan. For most people, there is a low risk associated with eating grilled food. Grilling food at a high temperature and/or on a campfire, often, and eating a lot of it may damage one's health. Distance to the heat source, how early food is placed onto the grill, and the type of fuel used can affect the formation of harmful substances. It is known that heat treatment such as grilling and frying can give rise to unwanted toxic compounds in the food, so-called process-induced contaminants. Grilling is a common way of preparing food in Norway, and the grilling season has become longer. The food selection has become ever wider and sales of different types of grills are increasing. Many factors may thus have changed since VKM's previous assessment of health risks from the consumption of grilled food, which was published in 2007. To be able to give current and relevant advice to consumers and others who sell or offer grilled food, the Norwegian Food Safety Authority has asked VKM for updated knowledge about the formation of process-induced contaminants in different food products by different grilling methods, and an assessment of what risk this may pose. Main findings: Harmful substances can be formed at high cooking temperatures. When grilling, the temperature is higher and less controllable than when frying in a pan. There is good evidence that two groups of genotoxic and carcinogenic substances, heterocyclic amines (HAA) and polycyclic aromatic hydrocarbons (PAH), are formed in higher concentrations in grilled food than in fried food. VKM has assessed PAH, for which there are good studies of occurrence in barbecued food. PAHs are formed when fat burns after dripping from the food onto the heat source. PAHs can also be released from coal, briquettes and wood. The smoke with PAH settles on the food. The occurrence of PAH in grilled food varies greatly and depends on how the food is grilled. The concentration of PAH is highest in very well-done meat with a high fat content, such as pork ribs and hamburgers. The highest concentration of PAH was found in sausage grilled on a campfire. This is caused by unburnt fat or soot/smoke from the fire that stick to the sausage. By avoiding fat dripping directly onto the heat source, preventing smoke from coming into contact with the food, and not overcooking the food, the amount of PAH in grilled food can be reduced. When using charcoal, the PAH emission is higher immediately after lighting, and the amount of PAH in the food can be reduced by waiting sufficiently long before start grilling. It is not the number of times you grill that is a critical factor, but how. A "worst-case" scenario shows that the annual consumption of more than 15-25 meals that have been grilled in a way that produces a high PAH incidence may provide too low margin of exposure* for the risk to be low. If, on the other hand, you prefer lean barbecue food that is not overcooked, then you can eat it more than 100 times a year according to our calculations and still have a high enough margin of exposure. * Margin of exposure is the ratio between the lowest dose (reference point) that causes increased cancer in experimental animals and the calculated intake. Exposure margin below 10,000 is considered a public health concern. Norsk: Ved grilling kan det dannes flere helseskadelige stoffer enn ved steking i panne. For de fleste er det lav risiko knyttet til å spise grillmat.Risk assessment of grilled and barbecued foodpublishedVersionacceptedVersionacceptedVersio

Risk assessment of grilled and barbecued food

When grilling, more harmful substances can be formed than when frying in a pan. For most people, there is a low risk associated with eating grilled food. Grilling food at a high temperature and/or on a campfire, often, and eating a lot of it may damage one's health. Distance to the heat source, how early food is placed onto the grill, and the type of fuel used can affect the formation of harmful substances. It is known that heat treatment such as grilling and frying can give rise to unwanted toxic compounds in the food, so-called process-induced contaminants. Grilling is a common way of preparing food in Norway, and the grilling season has become longer. The food selection has become ever wider and sales of different types of grills are increasing. Many factors may thus have changed since VKM's previous assessment of health risks from the consumption of grilled food, which was published in 2007. To be able to give current and relevant advice to consumers and others who sell or offer grilled food, the Norwegian Food Safety Authority has asked VKM for updated knowledge about the formation of process-induced contaminants in different food products by different grilling methods, and an assessment of what risk this may pose. Main findings: Harmful substances can be formed at high cooking temperatures. When grilling, the temperature is higher and less controllable than when frying in a pan. There is good evidence that two groups of genotoxic and carcinogenic substances, heterocyclic amines (HAA) and polycyclic aromatic hydrocarbons (PAH), are formed in higher concentrations in grilled food than in fried food. VKM has assessed PAH, for which there are good studies of occurrence in barbecued food. PAHs are formed when fat burns after dripping from the food onto the heat source. PAHs can also be released from coal, briquettes and wood. The smoke with PAH settles on the food. The occurrence of PAH in grilled food varies greatly and depends on how the food is grilled. The concentration of PAH is highest in very well-done meat with a high fat content, such as pork ribs and hamburgers. The highest concentration of PAH was found in sausage grilled on a campfire. This is caused by unburnt fat or soot/smoke from the fire that stick to the sausage. By avoiding fat dripping directly onto the heat source, preventing smoke from coming into contact with the food, and not overcooking the food, the amount of PAH in grilled food can be reduced. When using charcoal, the PAH emission is higher immediately after lighting, and the amount of PAH in the food can be reduced by waiting sufficiently long before start grilling. It is not the number of times you grill that is a critical factor, but how. A "worst-case" scenario shows that the annual consumption of more than 15-25 meals that have been grilled in a way that produces a high PAH incidence may provide too low margin of exposure* for the risk to be low. If, on the other hand, you prefer lean barbecue food that is not overcooked, then you can eat it more than 100 times a year according to our calculations and still have a high enough margin of exposure. * Margin of exposure is the ratio between the lowest dose (reference point) that causes increased cancer in experimental animals and the calculated intake. Exposure margin below 10,000 is considered a public health concern. Norsk: Ved grilling kan det dannes flere helseskadelige stoffer enn ved steking i panne. For de fleste er det lav risiko knyttet til å spise grillmat.Risk assessment of grilled and barbecued foodpublishedVersionacceptedVersio

New Approach Methods (NAMs) for genotoxicity assessment of nano- and advanced materials; Advantages and challenges

Genotoxicity assessment is essential for ensuring chemical safety and mitigating risks to human health and the environment. Traditional methods, reliant on animal models, are time-consuming, costly, and raise ethical concerns. New Approach Methods (NAMs) offer innovative, cost-effective, and ethical alternatives, playing a pivotal role in both traditional and next-generation risk assessment (NGRA) by minimizing the need for animal testing, particularly in genotoxicity evaluations. However, the development of NAMs often overlooks the particular physicochemical properties of nanomaterials (NMs), which significantly influence their toxicological behaviour and can interfere with genotoxicity evaluation. This underscores an urgent need for the standardization and adaptation of NAMs to address nano- and advanced material-specific genotoxicity challenges. In this review, we summarize the challenges associated with genotoxicity testing of NMs and highlight the suitability of existing in vitro and in silico NAMs for NMs and advanced materials, enabling genotoxicity testing across various exposure routes and organ systems. Despite considerable progress, regulatory validation remains constrained by the absence of approved test guidelines and standardized protocols. To achieve regulatory acceptance, it is crucial to adapt NAMs to NM-specific exposure scenarios, refine test systems to better mimic human biology, develop tailored in vitro protocols, and ensure thorough characterisation of NMs both in pristine form and dispersed in culture medium. Collaborative efforts among scientists, regulators, industry, and advocacy groups are vital to improving the reliability and regulatory acceptance of NAMs. By addressing these challenges, NAMs have the potential to revolutionize genotoxicity risk assessment, advancing it towards a more sustainable, efficient and ethical framework.publishedVersio

Hazard characterization of the mycotoxins enniatins and beauvericin to identify data gaps and improve risk assessment for human health

Enniatins (ENNs) and beauvericin (BEA) are cyclic hexadepsipeptide fungal metabolites which have demonstrated antibiotic, antimycotic, and insecticidal activities. The substantial toxic potentials of these mycotoxins are associated with their ionophoric molecular properties and relatively high lipophilicities. ENNs occur extensively in grain and grain-derived products and are considered a food safety issue by the European Food Safety Authority (EFSA). The tolerable daily intake and maximum levels for ENNs in humans and animals remain unestablished due to key toxicological and toxicokinetic data gaps, preventing full risk assessment. Aiming to find critical data gaps impeding hazard characterization and risk evaluation, this review presents a comprehensive summary of the existing information from in vitro and in vivo studies on toxicokinetic characteristics and cytotoxic, genotoxic, immunotoxic, endocrine, reproductive and developmental effects of the most prevalent ENN analogues (ENN A, A1, B, B1) and BEA. The missing information identified showed that additional studies on ENNs and BEA have to be performed before sufficient data for an in-depth hazard characterisation of these mycotoxins become available.Hazard characterization of the mycotoxins enniatins and beauvericin to identify data gaps and improve risk assessment for human healthpublishedVersio

Using prediction models to identify miRNA-based markers of low dose rate chronic stress

publishedVersio

MiRNA profiles in blood plasma from mother-child duos in human biobanks and the implication of sample quality: Circulating miRNAs as potential early markers of child health

BackgroundMicroRNAs (miRNAs) have been linked to several diseases and to regulation of almost every biological process. This together with their stability while freely circulating in blood suggests that they could serve as minimal-invasive biomarkers for a wide range of diseases. Successful miRNA-based biomarker discovery in plasma is dependent on controlling sources of preanalytical variation, such as cellular contamination and hemolysis, as they can be major causes of altered miRNA expression levels. Analysis of plasma quality is therefore a crucial step for the best output when searching for novel miRNA biomarkers.MethodsPlasma quality was assessed by three different methods in samples from mother-child duos (maternal and cord blood, N = 2x38), with collection and storage methods comparable to large cohort study biobanks. Total RNA was isolated and the expression profiles of 201 miRNAs was obtained by qPCR to identify differentially expressed miRNAs in cord and maternal plasma samples.ResultsAll three methods for quality assurance indicate that the plasma samples used in this study are of high quality with very low levels of contamination, suitable for analysis of circulating miRNAs. We identified 19 significantly differentially expressed miRNAs between cord and maternal plasma samples (paired t-tests, FDR±1.5), and we observed low correlation of miRNA transcript levels between cord and maternal samples throughout our dataset.ConclusionsOur findings suggest that good quality plasma samples suitable for miRNA profiling can be achieved from samples collected and stored by large biobanks. Incorporation of extensive quality control measures, such as those established here, would be beneficial for future projects. The overall low correlation of miRNA expression between cord and maternal samples is an interesting observation, and promising for our future studies on identification of miRNA-based biomarkers in cord blood plasma, considering that these samples were collected at term and some exchange of blood components between cord and maternal blood frequently occur