Screening for Rare Mitochondrial Genome Variants Reveals a Potentially Novel Association between MT-CO1 and MT-TL2 Genes and Diabetes Phenotype.

Variations in several nuclear genes predisposing humans to the development of MODY diabetes have been very well characterized by modern genetic diagnostics. However, recent reports indicate that variants in the mtDNA genome may also be associated with the diabetic phenotype. As relatively little research has addressed the entire mitochondrial genome in this regard, the aim of the present study is to evaluate the genetic variations present in mtDNA among individuals susceptible to MODY diabetes. In total, 193 patients with a MODY phenotype were tested with a custom panel with mtDNA enrichment. Heteroplasmic variants were selected for further analysis via further sequencing based on long-range PCR to evaluate the potential contribution of frequent NUMTs (acronym for nuclear mitochondrial DNA) insertions. Twelve extremely rare variants with a potential damaging character were selected, three of which were likely to be the result of NUMTs from the nuclear genome. The variant m.3243A>G in MT-TL1 was responsible for 3.5% of MODY cases in our study group. In addition, a novel, rare, and possibly pathogenic leucine variant m.12278T>C was found in MT-TL2. Our findings also found the MT-CO1 gene to be over-represented in the study group, with a clear phenotype-genotype correlation observed in one family. Our data suggest that heteroplasmic variants in MT-COI and MT-TL2 genes may play a role in the pathophysiology of glucose metabolism in humans.

Activity of Lysosomal ABCC3, ABCC5 and ABCC10 is Responsible for Lysosomal Sequestration of Doxorubicin and Paclitaxel-Oregongreen488 in Paclitaxel-Resistant Cancer Cell Lines.

BACKGROUND/AIMS: Cancer cell multidrug resistance induced by paclitaxel contributes to the high failure rates of chemotherapy and relapse of the disease. Several mechanisms have been described that underlie the observed resistance, including the overexpression of ABCB1 (P-glycoprotein), which represents an ATP-binding cassette (ABC) transmembrane protein, and its functional occurrence in lysosomal membranes is linked to drug accumulation in these organelles. METHODS: Using clinically-relevant models of paclitaxel-resistant triple-negative breast cancer and non-small cell lung cancer cell lines, we provide evidence for the role of ABCC subfamily members in the lysosomal sequestration of drugs in multidrug resistant phenotypes. Proteins expression level and its cellular localisation was measured using Western Blot and confocal microscopy. Drug accumulation was analysed by confocal microscopy and flow cytometry. Drug cytotoxicity was tested using resasurin assay and anexin V propidium iodide staining. RESULTS: Regardless of the alteration in gene expression, paclitaxel induced the intracellular redistribution of ABCC3, ABCC5 and ABCC10 and their enrichment in lysosomes. The use of ABCC inhibitors and transient silencing of these three genes limited the accumulation of doxorubicin and paclitaxel-OregonGreen488 in lysosomes, while having little impact on the total drug level inside cells. The cancer cells were also sensitized to various structurally unrelated chemotherapeutics of differing acidity. CONCLUSION: The results suggest that lysosome membranes anchored ABCC proteins which remained functionally active and were capable to load chemotherapeutics into lysosomes in paclitaxel-resistant cancer cells. Therefore, targeting of lysosomal ABCC transporters may help to overcome paclitaxel-induced resistance by reducing the accumulation of drugs in lysosomes.

Cells Lacking PA200 Adapt to Mitochondrial Dysfunction by Enhancing Glycolysis via Distinct Opa1 Processing.

The conserved Blm10/PA200 proteins are proteasome activators. Previously, we identified PA200-enriched regions in the genome of SH-SY5Y neuroblastoma cells by chromatin immunoprecipitation (ChIP) and ChIP-seq analysis. We also found that selective mitochondrial inhibitors induced PA200 redistribution in the genome. Collectively, our data indicated that PA200 regulates cellular homeostasis at the transcriptional level. In the present study, our aim is to investigate the impact of stable PA200 depletion (shPA200) on the overall transcriptome of SH-SY5Y cells. RNA-seq data analysis reveals that the genetic ablation of PA200 leads to overall changes in the transcriptional landscape of SH-SY5Y neuroblastoma cells. PA200 activates and represses genes regulating metabolic processes, such as the glycolysis and mitochondrial function. Using metabolic assays in live cells, we showed that stable knockdown of PA200 does not change basal respiration. Spare respiratory capacity and proton leak however are slightly, yet significantly, reduced in PA200-deficient cells by 99.834% and 84.147%, respectively, compared to control. Glycolysis and glycolytic capacity show a 42.186% and 26.104% increase in shPA200 cells, respectively, compared to control. These data suggest a shift from oxidative phosphorylation to glycolysis especially when cells are exposed to oligomycin-induced stress. Furthermore, we observed a preserved long and compact tubular mitochondrial morphology after inhibition of ATP synthase by oligomycin, which might be associated with the glycolytic change of shPA200 cells. The present study also demonstrates that the proteolytic cleavage of Opa1 is affected, and that the level of OMA1 is significantly reduced in shPA200 cells upon oligomycin-induced mitochondrial insult. Together, these findings suggest a role for PA200 in the regulation of metabolic changes in response to selective inhibition of ATP synthase in an in vitro cellular model.

The proteasome activator PA200 regulates expression of genes involved in cell survival upon selective mitochondrial inhibition in neuroblastoma cells.

The conserved Blm10/PA200 activators bind to the proteasome core and facilitate peptide and protein turnover. Blm10/PA200 proteins enhance proteasome peptidase activity and accelerate the degradation of unstructured proteasome substrates. Our knowledge about the exact role of PA200 in diseased cells, however, is still limited. Here, we show that stable knockdown of PA200 leads to a significantly elevated number of cells in S phase after treatment with the ATP synthase inhibitor, oligomycin. However, following exposure to the complex I inhibitor rotenone, more PA200-depleted cells were in sub-G1 and G2/M phases indicative of apoptosis. Chromatin immunoprecipitation (ChIP) and ChIP-seq data analysis of collected reads indicate PA200-enriched regions in the genome of SH-SY5Y. We found that PA200 protein peaks were in the vicinity of transcription start sites. Gene ontology annotation revealed that genes whose promoters were enriched upon anti-PA200 ChIP contribute to the regulation of crucial intracellular processes, including proliferation, protein modifications and metabolism. Selective mitochondrial inhibitors induced PA200 redistribution in the genome, leading to protein withdrawal from some gene promoters and binding to others. Collectively, the results support a model in which PA200 potentially regulates cellular homeostasis at the transcriptional level, in addition to its described role as an alternative activator of the proteasome.

Contribution of BRG1-dependent SWI/SNF complexes to determining the phenotype of cancer cell / Udzial kompleksów SWI/SNF opartych na aktywnosci BRG1 w determinowaniu fenotypu komórek nowotworowych.

ATP-dependent chromatin remodeling complexes are documented as indispensible element of epigenetic mechanisms, which control transcription. These multiprotein functional units are capable of insertion, deletion and sliding of nucleosomes at the gene regulatory elements thereby defining DNA accessibility to transcription machinery. SWI/SNF is one out of four identified and described complexes. The enzymatic role in SWI/SNF molecular "motors" is assigned to two ATP-ases: BRM and BRG1. Accumulating evidence suggests the link between BRG1 and pathophysiology of some types of cancer. BRG1 has been documented as an activator of genes encoding factors responsible for i.a. proliferation, DNA repair, transmembrane transport and metabolism. Therefore, inhibitors of BRG1 and co-operating enzymes, which modulate activity of this ATP-ase or mark histones for shuttling to/from the chromatin, may turn out as an alternative to the compounds that are currently used to suppress the growth of tumors or as supplements that increase cell vulnerability to anticancer drugs.

Analysis of medieval mtDNA from Napole cemetery provides new insights into the early history of Polish state.

Contemporary historical anthropology and classical archaeology are concerned not only with such fundamental issues as the origins of ancient human populations and migration routes, but also with the formation and development of inter-population relations and the mixing of gene pools as a result of inter-breeding between individuals representing different cultural units. The contribution of immigrants to the analysed autochthonous population and their effect on the gene pool of that population has proven difficult to evaluate with classical morphological methods. The burial of one individual in the studied Napole cemetery located in central Poland had the form of a chamber grave, which is typical of Scandinavian culture from that period. However, this fact cannot be interpreted as absolute proof that the individual (in the biological sense) was allochtonous. This gives rise to the question as to who was actually buried in that cemetery. The ancient DNA results indicate that one of the individuals had an mtDNA haplotype typical of Iron Age northern Europe, which suggests that he could have arrived from that area at a later period. This seems to indirectly confirm the claims of many anthropologists that the development of the early medieval Polish state was significantly and directly influenced by the Scandinavians.

HOCl-modified phosphatidylcholines induce apoptosis and redox imbalance in HUVEC-ST cells.

Electrophilic attack of hypochlorous acid on unsaturated bonds of fatty acyl chains is known to result mostly in chlorinated products that show cytotoxicity to some cell lines and were found in biological systems exposed to HOCl. This study aimed to investigate more deeply the products and the mechanism underlying cytotoxicity of phospholipid-HOCl oxidation products, synthesized by the reaction of HOCl with 1-stearoyl-2-oleoyl-, 1-stearoyl-2-linoleoyl-, and 1-stearoyl-2-arachidonyl-phosphatidylcholine. Phospholipid chlorohydrins were found to be the most abundant among obtained products. HOCl-modified lipids were cytotoxic towards HUVEC-ST (endothelial cells), leading to a decrease of mitochondrial potential and an increase in the number of apoptotic cells. These effects were accompanied by an increase of the level of active caspase-3 and caspase-7, while the caspase-3/-7 inhibitor Ac-DEVD-CHO dramatically decreased the number of apoptotic cells. Phospholipid-HOCl oxidation products were shown to affect cell proliferation by a concentration-dependent cell cycle arrest in the G0/G1 phase and activating redox sensitive p38 kinase. The redox imbalance observed in HUVEC-ST cells exposed to modified phosphatidylcholines was accompanied by an increase in ROS level, and a decrease in glutathione content and antioxidant capacity of cell extracts.

Characteristics of anticancer activity of CBP/p300 inhibitors - Features of their classes, intracellular targets and future perspectives of their application in cancer treatment.

Due to the contribution of highly homologous acetyltransferases CBP and p300 to transcription elevation of oncogenes and other cancer promoting factors, these enzymes emerge as possible epigenetic targets of anticancer therapy. Extensive efforts in search for small molecule inhibitors led to development of compounds targeting histone acetyltransferase catalytic domain or chromatin-interacting bromodomain of CBP/p300, as well as dual BET and CBP/p300 inhibitors. The promising anticancer efficacy in in vitro and mice models led CCS1477 and NEO2734 to clinical trials. However, none of the described inhibitors is perfectly specific to CBP/p300 since they share similarity of a key functional domains with other enzymes, which are critically associated with cancer progression and their antagonists demonstrate remarkable clinical efficacy in cancer therapy. Therefore, we revise the possible and clinically relevant off-targets of CBP/p300 inhibitors that can be blocked simultaneously with CBP/p300 thereby improving the anticancer potential of CBP/p300 inhibitors and pharmacokinetic predicting data such as absorption, distribution, metabolism, excretion (ADME) and toxicity.

PARP1 at the crossroad of cellular senescence and nucleolar processes.

Senescent cells that occur in response to telomere shortening, oncogenes, extracellular and intracellular stress factors are characterized by permanent cell cycle arrest, the morphological and structural changes of the cell that include the senescence-associated secretory phenotype (SASP) and nucleoli rearrangement. The associated DNA lesions induce DNA damage response (DDR), which activates the DNA repair protein - poly-ADP-ribose polymerase 1 (PARP1). This protein consumes NAD+ to synthesize ADP-ribose polymer (PAR) on its own protein chain and on other interacting proteins. The involvement of PARP1 in nucleoli processes, such as rRNA transcription and ribosome biogenesis, the maintenance of heterochromatin and nucleoli structure, as well as controlling the crucial DDR protein release from the nucleoli to nucleus, links PARP1 with cellular senescence and nucleoli functioning. In this review we describe and discuss the impact of PARP1-mediated ADP-ribosylation on early cell commitment to senescence with the possible role of senescence-induced PARP1 transcriptional repression and protein degradation on nucleoli structure and function. The cause-effect interplay between PARP1 activation/decline and nucleoli functioning during senescence needs to be studied in detail.

I-CBP112 declines overexpression of ATP-binding cassette transporters and sensitized drug-resistant MDA-MB-231 and A549 cell lines to chemotherapy drugs.

Despite extensive efforts and ongoing progress in personalized anticancer approaches, chemotherapy remains the first line or the only treatment for some tumors that may develop resistance to chemotherapeutics in time due to inter alia overexpression of ATP-binding cassette transporters. Using clinically-relevant resistant models of triple negative breast cancer (MDA-MB-231; TNBC) as well as non-small cell lung cancer (A549; NSCLC), we tested the efficacy of I-CBP112 - CBP/EP300 bromodomain inhibitor to overcome drug resistance by declining ABC gene transcription. I-CBP112 significantly reduced ABCB1, ABCC1, ABCC2, ABCC3, ABCC5 and ABCG2 in all resistant lines, as well as ABCC10 in TNBC and ABCC4 in paclitaxel-resistant NSCLC, thereby increasing intracellular drug accumulation and cytotoxicity in 2D and 3D cultures. This was phenocopied only by the joint effect of ABC inhibitors such as tariquidar (ABCB1 - P-glycoprotein and ABCG2) and MK-571 (ABCC), whereas single inhibition of ABCB1/ABCG2 or ABCC proteins did not affect drug accumulation, thereby implying the need of simultaneous deficiency in activity of majority of drug pumps for enhanced drug retention. I-CBP112 failed to directly inhibit activity of ABCB1, ABCG2 and ABCC subfamily members at the same time. Importantly, I-CBP112 treated cancer cells polarized human macrophages into proinflammatory phenotypes. Moreover, I-CBP112 remained non-toxic to primary cell lines, nor did it enhance anticancer drug toxicity to blood-immune cells. In silico assay of ADMET properties confirmed the desired pharmacokinetic features of I-CBP112. The results suggest that the CBP/p300 inhibitor is a promising co-adjuvant to chemotherapy in drug-resistant cancer phenotypes, capable of decreasing ABC transporter expression.

Activation of ABCC Genes by Cisplatin Depends on the CoREST Occurrence at Their Promoters in A549 and MDA-MB-231 Cell Lines.

Although cisplatin-based therapies are common among anticancer approaches, they are often associated with the development of cancer drug resistance. This phenomenon is, among others, caused by the overexpression of ATP-binding cassette, membrane-anchored transporters (ABC proteins), which utilize ATP to remove, e.g., chemotherapeutics from intracellular compartments. To test the possible molecular basis of increased expression of ABCC subfamily members in a cisplatin therapy mimicking model, we generated two cisplatin-resistant cell lines derived from non-small cell lung cancer cells (A549) and triple-negative breast cancer cells (MDA-MB-231). Analysis of data for A549 cells deposited in UCSC Genome Browser provided evidence on the negative interdependence between the occurrence of the CoREST complex at the gene promoters and the overexpression of ABCC genes in cisplatin-resistant lung cancer cells. Pharmacological inhibition of CoREST enzymatic subunits-LSD1 and HDACs-restored gene responsiveness to cisplatin. Overexpression of CoREST-free ABCC10 in cisplatin-resistant phenotypes was caused by the activity of EP300 that was enriched at the ABCC10 promoter in drug-treated cells. Cisplatin-induced and EP300-dependent transcriptional activation of ABCC10 was only possible in the presence of p53. In summary, the CoREST complex prevents the overexpression of some multidrug resistance proteins from the ABCC subfamily in cancer cells exposed to cisplatin. p53-mediated activation of some ABCC genes by EP300 occurs once their promoters are devoid of the CoREST complex.

CBP/p300 Bromodomain Inhibitor-I-CBP112 Declines Transcription of the Key ABC Transporters and Sensitizes Cancer Cells to Chemotherapy Drugs.

The high expression of some ATP-binding cassette (ABC) transporters is linked to multidrug resistance in cancer cells. We aimed to determine if I-CBP112, which is a CBP/p300 bromodomain inhibitor, altered the vulnerability of the MDA-MB-231 cell line to chemotherapy drugs, which are used in neoadjuvant therapy in patients with triple negative breast cancer (TNBC). MDA-MB-231 cells represent TNBC, which is negative for the expression of estrogen and progesterone receptors and HER2 protein. An I-CBP112-induced decrease in the expression of all the studied ABCs in the breast, but also in the lung (A549), and hepatic (HepG2) cancer cell lines was associated with increased accumulation of doxorubicin, daunorubicin, and methotrexate inside the cells as well as with considerable cell sensitization to a wide range of chemotherapeutics. Gene promoters repressed by I-CBP112 in MDA-MB-231 cells, such as ABCC1 and ABCC10, were characterized by enhanced nucleosome acetylation and, simultaneously, by considerably lower trimethylation in the transcription-promoting form of H3K4me3. The CBP/p300 bromodomain inhibitor induced the recruitment of LSD1 to the gene promoters. The inhibition of this demethylase in the presence of I-CBP112 prevented the repression of ABCC1 and ABCC10 and, to a considerable extent, cancer cells' sensitization to drugs. In conclusion, the CBP/p300 bromodomain inhibitor I-CBP112 can be considered as a potent anti-multidrug-resistance agent, capable of repressing key ABC transporters responsible for drug efflux in various cancer types.

PARP Traps Rescue the Pro-Inflammatory Response of Human Macrophages in the In Vitro Model of LPS-Induced Tolerance.

Secondary infections cause sepsis that lead to patient disability or death. Contact of macrophages with bacterial components (such as lipopolysaccharide-LPS) activates the intracellular signaling pathway downstream of Toll-like receptors (TLR), which initiate an immune proinflammatory response. However, the expression of nuclear factor-kappa B (NF-κB)-dependent proinflammatory cytokines significantly decreases after single high or multiple LPS stimulations. Knowing that poly(ADP-ribose) polymerase-1 (PARP1) serves as a cofactor of NF-κB, we aimed to verify a hypothesis of the possible contribution of PARP1 to the development of LPS-induced tolerance in human macrophages. Using TNF-α mRNA expression as a readout, we demonstrate that PARP1 interaction with the TNF-α promoter, controls macrophage immunoparalysis. We confirm that PARP1 is extruded from the gene promoter, whereas cell pretreatment with Olaparib maintains macrophage responsiveness to another LPS treatment. Furthermore, cell pretreatment with proteasome inhibitor MG132 completely abrogates the effect of Olaparib, suggesting that PARP1 acts with NF-κB in the same regulatory pathway, which controls pro-inflammatory cytokine transcription. Mechanistically, PARP1 trapping allows for the re-rebinding of p65 to the TNF-α promoter in LPS-stimulated cells. In conclusion, PARP traps prevent PARP1 extrusion from the TNF-α promoter upon macrophage stimulation, thereby maintaining chromatin responsiveness of TLR activation, allowing for the re-binding of p65 and TNF-α transcription.

LSD1 Facilitates Pro-Inflammatory Polarization of Macrophages by Repressing Catalase.

The increased level of hydrogen peroxide accompanies some modes of macrophage specification and is linked to ROS-based antimicrobial activity of these phagocytes. In this study, we show that activation of toll-like receptors with bacterial components such as LPS is accompanied by the decline in transcription of hydrogen peroxide decomposing enzyme-catalase, suppression of which facilitates the polarization of human macrophages towards the pro-inflammatory phenotype. The chromatin remodeling at the CAT promoter involves LSD1 and HDAC1, but activity of the first enzyme defines abundance of the two proteins on chromatin, histone acetylation status and the CAT transcription. LSD1 inhibition prior to macrophage activation with LPS prevents CAT repression by enhancing the LSD1 and interfering with the HDAC1 recruitment to the gene promoter. The maintenance of catalase level with LSD1 inhibitors during M1 polarization considerably limits LPS-triggered expression of some pro-inflammatory cytokines and markers such as IL1ß, TNFα, COX2, CD14, TLR2, and IFNAR, but the effect of LSD1 inhibitors is lost upon catalase deficiency. Summarizing, activity of LSD1 allows for the CAT repression in LPS stimulated macrophages, which negatively controls expression of some key pro-inflammatory markers. LSD1 inhibitors can be considered as possible immunosuppressive drugs capable of limiting macrophage M1 specialization.

[Markers of chloric acid (I) in biological systems--identification and properties]. / Markery kwasu chlorowego (I) w ukladach biologicznych--identyfikacja i wlasciwosci.

Reactive oxygen and nitrogen species are attributed to initiation and propagation of many diseases. The demonstration of elevated activity of myeloperoxidase and the level of 3-chlorotyrosine in atherosclerosis, kidney diseases and chronic inflammations brought about the interest in the biological role of another strong oxidant--hypochlorite. Concentration of this compound is extremely difficult to estimate in vivo and in vitro because of its high reactivity. The reaction of hypochlorite with biological compounds lead to formation of chlorohydrins, glutathione sulfonamides, chloramines, 3- and 3,5-dichlorotyrosines and chlorinated DNA bases (8-chloroadenine, 8-chloroguanine, 5-chlorocytosine and 5-chlorouracil). At least some of these products of hypochlorite action are believed to provide specific HOCl-biomarkers, useful especially in the analysis of clinical samples, using sensitive detection techniques.

[Oxidative damage of mitochondrial DNA: the result or consequence of enhanced generation of reactive oxygen species]. / Oksydacyjne uszkodzenia mitochondrialnego DNA--przyczyna czy skutek zwiekszonej produkcji reaktywnych form tlenu.

According to mitochondrial theory of ageing the ageing process results from accumulation of mitochondrial DNA (mtDNA) damage. Close vicinity of mtDNA molecule to the source of reactive oxygen species, electron transport chain, potentiates degradation of nucleic acid chemical components. The most common types of mtDNA damage generated are point mutations as a result of oxidative modifications of purines and pyrimidines (transitions as well as transversions), but also deletions and rarely insertions. Since mtDNA codes for subunits of respiratory chain enzymes, its lesions can alter homeostasis of the cell resulting in a decrease of intracellular ATP. Growing evidence indicates the role of mtDNA mutations in elevated production of reactive oxygen species, which in turn are proved to increase the number of mtDNA mutations. This mechanism gave the basis for theory of a vicious cycle: ROS<-->mutations of mtDNA

The Role of PARP1 in Monocyte and Macrophage Commitment and Specification: Future Perspectives and Limitations for the Treatment of Monocyte and Macrophage Relevant Diseases with PARP Inhibitors.

Modulation of PARP1 expression, changes in its enzymatic activity, post-translational modifications, and inflammasome-dependent cleavage play an important role in the development of monocytes and numerous subtypes of highly specialized macrophages. Transcription of PARP1 is governed by the proliferation status of cells at each step of their development. Higher abundance of PARP1 in embryonic stem cells and in hematopoietic precursors supports their self-renewal and pluri-/multipotency, whereas a low level of the enzyme in monocytes determines the pattern of surface receptors and signal transducers that are functionally linked to the NFκB pathway. In macrophages, the involvement of PARP1 in regulation of transcription, signaling, inflammasome activity, metabolism, and redox balance supports macrophage polarization towards the pro-inflammatory phenotype (M1), which drives host defense against pathogens. On the other hand, it seems to limit the development of a variety of subsets of anti-inflammatory myeloid effectors (M2), which help to remove tissue debris and achieve healing. PARP inhibitors, which prevent protein ADP-ribosylation, and PARP1‒DNA traps, which capture the enzyme on chromatin, may allow us to modulate immune responses and the development of particular cell types. They can be also effective in the treatment of monocytic leukemia and other cancers by reverting the anti- to the proinflammatory phenotype in tumor-associated macrophages.

BRG1 Activates Proliferation and Transcription of Cell Cycle-Dependent Genes in Breast Cancer Cells.

Cancer malignancy is usually characterized by unlimited self-renewal. In some types of advanced tumors that are rapidly dividing, gene expression profiles depict elevations in pro-proliferative genes accompanied by coordinately elevated transcription of factors responsible for removal of DNA lesions. In our studies, fast proliferating breast cancer cell lines (MDA-MB-231 and MCF7), BRG1, a component of the SWI/SNF complex, emerges as an activator of functionally-linked genes responsible for activities such as mitotic cell divisions and DNA repair. Products of at least some of them are considerably overrepresented in breast cancer cells and BRG1 facilitates growth of MCF7 and MDA-MB-231 cell lines. BRG1 occurs at the promoters of genes such as CDK4, LIG1, and NEIL3, which are transcriptionally controlled by cell cycle progression and highly acetylated by EP300 in proliferating cells. As previously documented, in dividing cells BRG1 directly activates gene transcription by evicting EP300 modified nucleosomes from the promoters and, thereby, relaxing chromatin. However, the deficiency of BRG1 or EP300 activity for 48 h leads to cell growth arrest and to chromatin compaction, but also to the assembly of RB1/HDAC1/EZH2 complexes at the studied cell cycle-dependent gene promoters. Epigenetic changes include histone deacetylation and accumulation of H3K27me trimethylation, both known to repress transcription. Cell cycle arrest in G1 by inhibition of CDK4/6 phenocopies the effect of the long-term BRG1 inhibition on the chromatin structure. These results suggest that BRG1 may control gene transcription also by promoting expression of genes responsible for cell cycle progression in the studied breast cancer cells. In the current study, we show that BRG1 binding occurs at the promoters of functionally linked genes in proliferating breast cancer cells, revealing a new mechanism by which BRG1 defines gene transcription.

Analysis of maternal lineage structure of individuals from chamber graves placed in medieval cemetery in Kaldus, Central Poland.

The beginning of the early Middle Ages period in Poland (10th-14th century) has been widely debated in the context of an active demographic inflow from other countries and its contribution to the creation of the new country. Finding chamber graves which are considered typical for the Scandinavian ethnic group in a few cemeteries in Poland has become the basis for the anthropological inference on the potential participation of North European people in forming the social elite of medieval Poland. However, the question of whether this fact was the result of presence of people from other countries lacks an unambiguous answer. We attempted to isolate ancient DNA from the medieval necropolis in Kaldus where several chamber graves have been found and analysed the genetic diversity of maternal lineage of this population. We analysed the HVR I fragment and coding regions to assess the mitochondrial DNA haplogroup. We have identified a few relatively rare haplogroups (A2, T2b4a, HV, K1a11, J2b1a, and X2) which were previously found in early medieval sites in Norway and Denmark. Obtained results might suggest genetic relation between the people of Kaldus and past northern Europe populations. Present and further research can undoubtedly shed new light on the aspect of the formation of the early medieval Polish population.

Estimation of antioxidant capacity against pathophysiologically relevant oxidants using Pyrogallol Red.

Peroxynitrite and hypochlorite are oxidants relevant in many pathological situations. We propose a simple spectrophotometric assay to determine antioxidant capacity against hypochlorite and peroxynitrite based on protection against Pyrogallol Red decolorization. The assay can be performed on a microplate and requires minute amounts of material. Standard antioxidants show different reactivities for both oxidants. Antioxidant capacity of blood plasma (anticoagulated with EDTA) of healthy persons was found to be 559+/-49 micromol/l and 11.6+/-1.2 mmol/l of ascorbic acid equivalents for peroxynitrite and hypochlorite, respectively.