P–006 Simultaneous determination of bisphenol A and S in the samples of human seminal fluid

Study question

Can we quantitatively determine concentrations of endocrine disruptors namely bisphenol A and S in seminal fluid?

Summary answer

We developed selective analytical method to simultaneously screen for the presence of bisphenol A (BPA) and S (BPS).

What is known already

The male reproductive system involves processes, which may be influenced by the disruption of the endocrine system by chemicals called endocrine disruptors (EDs). There is a growing evidence that EDs such as bisphenol A and S may be responsible for the decline in male reproductive health. To date, the claimed adverse effects on male fertility are largely based on the results from studies assessing the relationship between urinary BPA and BPS concentration and semen parameters. The best evidence of an adverse effect of BPA and BPS directly on spermatozoa could be provided by measuring bisphenols concentration directly in seminal fluid.

Study design, size, duration

To selectively and quantitatively analyzed bisphenols in any biological matrix advanced analytical tools and selective sample preparation protocols must be employed. In this study we developed targeted analytical method based on liquid chromatography tandem mass (LC-MS/MS) detection to measure bisphenol A and S in seminal fluid samples obtained from IVF clinic. A total of 140 samples were analysed.

Participants/materials, setting, methods

BPA and BPS was extracted from 140 seminal fluid samples using solvent extraction followed by preconcentration step. Samples were analyzed on Agilent 6495 Triple Quadrupole (Agilent Technologies, Santa Clara, CA) operating in the ESI-negative mode. Two MS/MS transitions were used for quantitative LC-MS/MS analyses. Chromatographic separation was achieved on Waters™ ACQUITY™ UPLC™BEH C18 (100 × 2.1 mm, 1.7 µm) column using gradient elution with a mixture of 0.1mM ammonium fluoride and methanol as mobile phases.

Main results and the role of chance

We developed selective sample preparation method for detection of BPA and BPS in seminal fluid followed by LC-MS/MS detection. The method validation was performed based on FDA guidelines. Validation criteria included limit of detection (LOD), limit of quantitation (LOQ), accuracy and precision. Due to the lack of the certified reference material the validation criteria of the method were assessed in pool of spiked seminal samples. The accuracy of the LC-MS/MS method was evaluated as a percent recovery of the amount of target analyte added into the sample. Recovery rates were above 80% for both analytes. LOD was 0.04 ng/mL for BPA and 0.01 ng/mL for BPS. LOQ was 0.14 ng/mL and 0.02 ng/mL for BPS. Measured BPA concentration ranged from 0.04 ng/mL to 1.62 ng/mL. For BPS, the concentration ranged from 0.01 ng/mL to 0.47 ng/mL. BPA and BPS were detected in 64% and 81% of samples, respectively. Interestingly, BPA showed lower detection frequency compared to BPS. These results are consistent with other studies performed on urine samples.

Limitations, reasons for caution

The limitation of the developed method is the time-consuming sample preparation and analysis cost.

Wider implications of the findings: These results document for the first time the presence of BPS in seminal fluid. Knowing the concentration of BPA and BPS in seminal fluid is crucial for mitigating the associated health risks and initiating intervention and prevention strategies. Our future work will evaluate the influence of BPS concentration on spermatozoa.

Trial registration number

AZV NV18–01–00544; CZ.02.2.69/0.0/0.0/19_074/0012727

Th e role of CDK12 in tumor bio logy

BACKGROUND

Physiological function of cyclin-dependent kinase 12 (CDK12) is crucial for several cellular processes, including regulation of transcription, RNA splicing, transcription termination and polyadenylation. It is well documented by now that CDK12 controls transcription of the unique set of genes involved in DNA-damage response, replication of DNA and response to cellular stress. Just recently, a key function of CDK12 in the induction of tandem duplication of specific DNA sequences within the metastatic castrate resistant prostate tumors has been documented. Therefore, it is possible to recognize CDK12 as a tumor suppressor; nevertheless, there is a growing body of evidence that CDK12 can support tumor growth under specific circumstances and thus act as a tumor oncogene. CDK12 therefore represents an alternative dia-gnostic approach for breast, ovarian and prostate tumors, especially when conventional treatment is not active and there is a need for more effective approaches, such as concept of synthetic lethality.

METHODS

The discussed scientific papers can be reached at the PubMed and Scopus databases before 1th of April 2020.

PURPOSE

The aim of the review is to summarize current knowledge relevant to the function of CDK12 as a tumor suppressor or oncogene in various tumors and to discuss the use of specific CDK12 inhibitors for patient treatment. At the end of the article, we discuss the potential use of CDK12 in the treatment of specific tumors by its targeted inhibition in monotherapy or in combination with poly (ADP ribose) polymerase 1 (PARP1) and checkpoint kinase 1 (CHK1) inhibitors. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.

Hematological findings in non-treated and gamma-irradiated mice deficient for MIC-1/GDF15

Several members of the TGF-beta family are known to effectively regulate the fate of hematopoietic progenitor cells in a complex and context-dependent manner. Growth differentiation factor-15 (GDF15) is a divergent member of the TGF-beta family. This stress-induced cytokine has been proposed to possess immunomodulatory functions and its high expression is often associated with progression of a variety of pathological conditions. GDF15 is also induced by chemotherapy and irradiation. Very few fundamental studies have been published regarding the effect of GDF15 in hematopoiesis. In this study, we analyzed the hematological status of untreated and gamma-irradiated mice deficient for GDF15 as a result of genetic knock-out (KO), in order to clarify the regulatory role of GDF15 in hematopoiesis. Significant differences between GDF15 KO mice and their pertinent WT controls were found in the parameters of blood monocyte numbers, blood platelet size, and distribution width, as well as in the values of bone marrow granulocyte/macrophage progenitor cells. Different tendencies of some hematological parameters in the GDF15 KO mice in normal conditions and those under exposure of the mice to ionizing radiation were registered. These findings are discussed in the context of the GDF15 gene function and its lack under conditions of radiation-induced damage.

Assessment of non-derivatized β-N-methylamino-l-alanine (BMAA) neurotoxin in free form in urine of patients with nonspecific neurological symptoms

The beta-N-methylamino-l-alanine (BMAA) is a non-proteinogenic amino acid discussed to be produced by cyanobacteria forming harmful blooms. Since BMAA is suspected etiological agent in neurodegenerative diseases, there is a need to study and validate whether and in what concentrations can BMAA be present in human tissues. The aim of the present study was to validate analytical and extraction procedures for quantification of non-derivatized BMAA in the urine using liquid chromatography and commercial ELISA Kit. The study was focused on BMAA in different forms - dissolved, protein associated and total. The validated protocol included SPE followed by HILIC MS/MS for analyses of non-derivatized free form of BMAA with a limit of quantification 20 ng/mL. The methods for other BMAA forms (i.e. protein-associated and total) were also assessed but high matrix interferences did not allow their implementation. The method was used for analyses of free BMAA in 23 urine samples from healthy volunteers and psychiatric patients suffering from nonspecific neurological symptoms. Traces of BMAA were suspectedly detected in a single urine sample but they were not unequivocally proved according to all conservative analytical criteria. BMAA was also not confirmed in a repeatedly collected sample from the same person. The evaluated commercial BMAA ELISA Kit (Abraxis) was not suitable for determination of BMAA in extracted urine samples because of systematically highly false positive results. In agreement with recent findings, analyses of BMAA appear to methodologically challenging, and further research on BMAA in human tissues (or its precursors with potency to form BMAA under natural conditions or - eventually - during sample processing) is needed to clarify its potential ethiological role in neurodegenerative diseases.

[Function of CDK12 in Tumor initiation and progression and its clinical consequences]

Cyclin-dependent kinases (CDKs) participate in many cellular processes and play a crucial role in the regulation of cell cycle and transcription processes. Recently, CDK12 was identified as a key factor orchestrating transcription of genes, such as BRCA1, ATM, ATR, FANCI and FANCD2, which are involved in the DNA-damage response pathway. Importantly, inhibition of function of these genes commonly leads to induction of genomic instability followed by cancer development, but the precise contribution of CDK12 to these processes is to be unveiled. Nevertheless, several mutations affecting function of CDK12 were already identified in a variety of tumors of different origin (ovary, breast, prostate, intestine) making tumors sensitive to cytostatics promot-ing DNA damage (platin derivatives, alkylating regimens) and inhibitors of DNA repair (PARP inhibitors). Such an effect has been already observed in the model of high grade serous ovarian carcinomas. Thus, CDK12 is becoming a potential therapeutic target of drugs causing synthetic lethality in these cells. Our review summarizes most recent information about CDK12 function in cancer and discusses potential use of CDK12 in clinics.

Simultaneous determination of reduced and oxidized glutathione in tissues by a novel liquid chromatography-mass spectrometry method: application in an inhalation study of Cd nanoparticles

The paper presents the development of an advanced extraction and fast analytical LC MS/MS method for simultaneous analyses of reduced and oxidized glutathione (GSH and GSSG, respectively) in different animal tissues. The simultaneous determination of GSH and GSSG is crucial because the amount and ratio of both GSH and GSSG may be altered in response to oxidative stress, an important mechanism of toxicity. The method uses the derivatization of free thiol groups in GSH. Its performance was demonstrated for less explored tissues (lung, brain, and liver) in mouse. The combined extraction and analytical method has very low variability and good reproducibility, maximum coefficients of variance for within-run and between-run analyses under 8 %, and low limits of quantification; for GSH and GSSG, these were 0.2 nM (0.06 ng/mL) and 10 nM (6 ng/mL), respectively. The performance of the method was further demonstrated in a model experiment addressing changes in GSH and GSSG concentrations in lung of mice exposed to CdO nanoparticles during acute 72 h and chronic 13-week exposures. Inhalation exposure led to increased GSH concentrations in lung. GSSG levels were in general not affected; nonsignificant suppression occurred only after the longer 13-week period of exposure. The developed method for the sensitive detection of both GSH and GSSG in very low tissue mass enables these parameters to be studied in cases where only a little sample is available, i.e. in small organisms or in small amounts of tissue.

Novel metabolites in cyanobacterium Cylindrospermopsis raciborskii with potencies to inhibit gap junctional intercellular communication

Despite intensive research into toxic bloom-forming cyanobacteria, the majority of their metabolites remain unknown. The present study explored in detail a novel bioactivity identified in cyanobacteria, i.e. inhibition of gap junctional intercellular communication (GJIC), a marker of tumor promotion. The extracellular mixture (exudate) of the cyanobacterial strain Cylindrospermopsis raciborskii (SAG 1.97) was fractionated by semi-preparative reversed phase HPLC, and the fractions assessed for their potencies to inhibit GJIC. Two non-polar fractions that significantly inhibited GJIC were further fractionated, tested and analyzed using multiple mass spectrometric methods. Investigations led to the identification of a putative chemical compound (molecular formula C18H34O3, m/z 299.2581 for the [M+H](+) ion) responsible for observed bioactivities. Specific inhibitors of signaling pathways were used to screen for biochemical mechanisms beyond GJIC inhibition, and the results indicate the involvement of ERK1/2 kinases via a mechanism related to the action of epidermal growth factor EGF but clearly distinct from other anthropogenic tumor promoters like polychlorinated biphenyls or polycyclic aromatic hydrocarbons. The chemical and in vitro toxicological characterizations of the newly described metabolite provide important insights into the still poorly understood health impacts of complex toxic cyanobacterial blooms and indicate that currently applied monitoring practices may underestimate actual risks.

Evaluation of genotoxic and non-genotoxic effects of organic air pollution using in vitro bioassays

In this study, organic extracts of total suspended particles (TSP) and the particulate matter (PM) with the size below 2.5 microm (PM(2.5)) combined with organic extracts of the gas phase (GP) collected at two urban and two background localities were analyzed with a bacterial genotoxicity test, SOS chromotest, and an in vitro test for the dioxin toxicity determination, using a modified cell-line of rat hepatoma H4IIE.luc. In addition, the samples of TSP and GP were analyzed for PAHs contents. The PAHs concentrations and both of the toxic activities at the urban localities were much higher than ones at the background localities. Predominantly, traffic was a source of the urban air pollution there which was also confirmed by the evaluation of portions of certain PAHs (BaP/BPE, PYR/BaP) at the localities. On the other hand, the background localities were apparently affected by a long-distance transport of the pollutants from urban and industrial centers. The results of the bioassays indicated potential health risks for the population exposed to the organic air pollutants, especially at the urban localities. Based on the collected samples, distribution of the organic pollutants with the toxic effects in the air was evaluated. The significant portion of the direct genotoxins was bound to the particles larger than 2.5 microm. On the contrary, the indirect genotoxins were bound predominantly to the particles with the size below 2.5 microm. However, in the urban air they may be also bound to the larger particles, as well. While the direct genotoxicity may be related with the presence of PAH-derivatives as well as some polar organic pollutants, the indirect genotoxicity is related with the detected carcinogenic PAHs. But besides the above specified pollutants it is also necessary to consider the presence of other toxic components of the complex organic air pollution mixture that may also show potential health risks. This study demonstrates application of the combination of the screening bioassays for the evaluation of organic air pollution and identification of its health risks.

A combined approach to the evaluation of organic air pollution - a case study of urban air in Sarajevo and Tuzla(Bosnia and Herzegovina)

Organic pollution is a complex mixture where besides usually discussed polycyclic aromatic hydrocarbons (PAHs) a lot of other toxic or potentially toxic compounds occur. In this case, the organic air pollution in two important industrial cities, Sarajevo and Tuzla, in Bosnia and Herzegovina (part of former Yugoslavia) was assessed with the emphasis placed on genotoxic risks using both chemical (PAHs analyses) and biological approaches (genotoxicity testing with a screening bacterial genotoxicity test - SOS chromotest). The study was performed as a part of the APOPSBAL project (ICA2-CT2002-10007). So far there has not been any information either about the PAHs pollution or the genotoxic activity of the organic air pollution for the localities under the study. Therefore, the presented information is considered absolutely unique. Both used approaches made possible to identify the localities with the highest pollution level and genotoxic risks in both cities. Generally, higher levels of both parameters were determined in Tuzla, which is much more industrialized than Sarajevo, and especially at localities close to city centers and affected by traffic emissions, but also at localities polluted by emissions from industry and household heating. Even if benzo(a)pyrene concentrations exceeded the maximum permitted levels for this pollutant at some localities in Tuzla, the PAHs concentrations were fully comparable with the levels determined in other industrial European cities. Significant genotoxicity of the organic extracts was detected for almost all of the urban localities in the test both without (-S9; direct genotoxicity) and with the addition of metabolic activation (+S9; indirect genotoxicity). The observed direct genotoxic activities were discussed in relation to a potential presence of PAHs derivatives in the air. The indirect genotoxic activities were apparently higher at the localities with higher contents of carcinogenic PAHs. The significant relationship between the determined genotoxic activities and the PAHs pollution was also confirmed by a regression analysis. However, the correlations were not absolute because the observed genotoxic activity was also dependent on the presence of other organic pollutants than the PAHs. It concerns predominantly direct genotoxicity which is not related with the PAHs, but with their nitro-, oxi-, and hydroxy-derivatives and also other unknown polar organic pollutants. However, the concentrations of the direct genotoxins apparently correlated with the PAHs contents in the air. The study showed that screening genotoxicity tests, such as the SOS chromotest, could be effectively used for the identification of localities with increased genotoxic risks. In comparison with the health risk assessment which is usually based on the chemical analyses of only a small part of the pollution mixture, the bioassays enable us to evaluate the risks of all the mixture. The localities with the highest detected human health risks according to the screening bioassays may then be analyzed in detail with specific chemical methods to identify their causes.

Expression of MHC II genes

Innate and adaptive immunity are connected via antigen processing and presentation (APP), which results in the presentation of antigenic peptides to T cells in the complex with the major histocompatibility (MHC) determinants. MHC class II (MHC II) determinants present antigens to CD4+ T cells, which are the main regulators of the immune response. Their genes are transcribed from compact promoters that form first the MHC II enhanceosome, which contains DNA-bound activators and then the MHC II transcriptosome with the addition of the class II transactivator (CIITA). CIITA is the master regulator of MHC II transcription. It is expressed constitutively in dendritic cells (DC) and mature B cells and is inducible in most other cell types. Three isoforms of CIITA exist, depending on cell type and inducing signals. CIITA is regulated at the levels of transcription and post-translational modifications, which are still not very clear. Inappropriate immune responses are found in several diseases, including cancer and autoimmunity. Since CIITA regulates the expression of MHC II genes, it is involved directly in the regulation of the immune response. The knowledge of CIITA will facilitate the manipulation of the immune response and might contribute to the treatment of these diseases.

Temporal distribution of CDK4, CDK6, D-type cyclins, and p27 in developing mouse oocytes

Various molecular interactions not operating in other cell types are most likely required for mammalian oocytes to develop into fully competent eggs. This study seeks to initiate analyses of the potential oocyte-specific functions of regulators of G1/S progression-CDK4, CDK6, D-type cyclins, and p27-by first determining their expression patterns in growing and maturing mouse oocytes and in mouse embryos early after fertilization. Western blot and immunofluorescence analyses on isolated oocytes were employed to evaluate both their levels and their localization. The data show that 1). mouse oocytes contain significant amounts of all studied regulators; 2). their amounts and localization undergo dramatic changes as the oocytes grow, meiotically mature, and transit into embryogenesis; and 3). some regulators (CDK4, CDK6, cyclin D2, and p27) appear in unusual, most likely posttranslationally modified, forms. These data distinguish G1/S regulators as the potential players in molecular processes that are important for oocytes to function normally.

Accumulation of the proteolytic marker peptide ubiquitin in the trophoblast of mammalian blastocysts

Ubiquitination is a universal protein degradation pathway in which the molecules of 8.5-kDa proteolytic peptide ubiquitin are covalently attached to the epsilon-amino group of the substrate's lysine residues. Little is known about the importance of this highly conserved mechanism for protein recycling in mammalian gametogenesis and fertilization. The data obtained by the students and faculty of the international training course Window to the Zygote 2000 demonstrate the accumulation of ubiquitin-cross-reactive structures in the trophoblast, but not in the inner cell mass of the expanding bovine and mouse blastocysts. This observation suggests that a major burst of ubiquitin-dependent proteolysis occurs in the trophoblast of mammalian peri-implantation embryos. This event may be important for the success of blastocyst hatching, differentiation of embryonic stem cells into soma and germ line, and/or implantation in both naturally conceived and reconstructed mammalian embryos.

Persistent, bioaccumulative, and toxic compounds in the central and eastern European countries--the-state-of-the-art report--human exposure

This review describes problems with persistent and bioaccumulative organic substances which posses toxic characteristics likely to cause adverse human health or environmental effects in countries of Central and Eastern Europe as far as human exposure is concerned. This paper is a part of a more detailed report on the subject.

Persistent, bioaccumulative, and toxic compounds in central and eastern Europe--hot spots

The sources and environmental levels of the PBTs in the countries of Central and Eastern Europe are broadly described. Most of the countries in the region produce and/or formulate pesticides. The pesticide registration is a primary requirement for import, production and distribution. The special attention must be given to unwanted pesticides. The problem of unwanted and expired pesticides pose the greatest danger to the natural environment and people which is brought about by the use of chemicals in agriculture in CEE countries. Countries still have not solve the problem of safety storage for PBTs and other chemicals classified as poisons and they have no special sites or facilities for destruction of these chemicals. This region has very specific problems of environmental pollution, which are the results of the recent wars. Destruction of industrial facilities and spilling of chemicals have the worst effect for the environment (Bosnia and Herzegovina, Croatia, Serbia and Montenegro).

Regional background monitoring of PBT compounds. The comparison of the results from measurements and modelling

A comparison of the modelling results of persistent, bioaccumulative and toxic (PBT) chemicals is presented with measurements. Contribution will present mean annual concentrations calculated and observed at EMEP stations and their ratios. The comparison of the calculated results with older results indicates that the model modification improved the agreement with measurement data. PBT compounds in ambient air are monitored in the area of Kosetice observatory (professional observatory of the Czech Hydrometeorological Institute located in south Bohemia). Calculated and measured mean annual concentrations of PBTs in precipitation, soil, vegetation and their ratios are presented. It should be mentioned that the number of measurements in such compartments as seawater, soil and vegetation is insufficient for model verification at present. The agreement between results from MSC-East models and results from long-term regional air background monitoring in Central Europe is good.

Retinoid X receptor suppresses transformation by the v-myb oncogene

The v-myb oncogene of avian myeloblastosis virus causes acute monoblastic leukemia in vivo and transforms myelomonocytic cells in culture. Retinoids are potent regulators of proliferation and differentiation in various cell types, and they can initiate differentiation in certain types of leukemic cells. However, the BM2 v-myb-transformed chicken monoblastic cell line is resistant to retinoic acid treatment. We found that overexpression of the retinoid X receptor confers sensitivity of BM2 cells to retinoic acid, resulting in induction of growth arrest and terminal differentiation. In contrast, the frequency of apoptosis was not affected by the retinoid X receptor in this cell type. We also demonstrated that suppression of transformation by v-Myb results from the negative effect of retinoid X receptor on v-Myb transactivation function, similar to that previously described for the retinoic acid receptor. The retinoid X receptor-induced inhibition of transactivation by v-Myb seems to be enhanced by a cell type-specific factor(s), which is not required by retinoic acid receptor.