The motility of breast cancer cells is stimulated by HMGB1/RAGE interaction but the truncated form lacking the C terminus has no effect

HMGB1/RAGE is identified as a ligand-receptor pair that plays an important role in tumorogenesis. HMGB1 and RAGE levels are higher in most human tumors and their overexpression is associated with tumor progression. The causes of breast cancer are still poorly understood. One reason might be the existence of subtypes within various cellular mechanisms as hormone-dependent and hormone -independent malignant processes. We investigated the effect of HMGB1 protein and its truncated form lacking the C terminus on the RAGE expression and cell motility of breast cancer cell lines; MCF7-noninvasive, MDA-MB-231-invasive and normal breast epithelial one MCF10. The results demonstrate that the effects of HMGB1 and HMGB1∆C through RAGE association are observed exclusively for the hormone independent MDA-MB-231 cell line. The mobility of MDA-MB-231 cells was stimulated only by the full length HMGB1. Our results suggest that HMGB1/RAGE signaling should be considered as an essential process for the development of hormone independent breast cancers with great invasive potential. The truncated form plays the role of a blocking molecule that ”locks” the receptor and inactivates it. This makes the tailless molecule a promising therapeutic agent that competes for the biologically active HMGB1 ligand and prevents the downstream signaling through RAGE

Resolution of R-loops by INO80 promotes DNA replication and maintains cancer cell proliferation and viability

Collisions between the DNA replication machinery and co-transcriptional R-loops can impede DNA synthesis and are a major source of genomic instability in cancer cells. How cancer cells deal with R-loops to proliferate is poorly understood. Here we show that the ATP-dependent chromatin remodelling INO80 complex promotes resolution of R-loops to prevent replication-associated DNA damage in cancer cells. Depletion of INO80 in prostate cancer PC3 cells leads to increased R-loops. Overexpression of the RNA:DNA endonuclease RNAse H1 rescues the DNA synthesis defects and suppresses DNA damage caused by INO80 depletion. R-loops co-localize with and promote recruitment of INO80 to chromatin. Artificial tethering of INO80 to a LacO locus enabled turnover of R-loops in cis. Finally, counteracting R-loops by INO80 promotes proliferation and averts DNA damage-induced death in cancer cells. Our work suggests that INO80-dependent resolution of R-loops promotes DNA replication in the presence of transcription, thus enabling unlimited proliferation in cancers

Possible Emergence of Sequence Specific RNA Aminoacylation via Peptide Intermediary to Initiate Darwinian Evolution and Code through Origin of Life

One of the most intriguing questions in biological science is how life originated on Earth. A large number of hypotheses have been proposed to explain it, each putting an emphasis on different events leading to functional translation and self-sustained system. Here, we propose a set of interactions that could have taken place in the prebiotic environment. According to our hypothesis, hybridization-induced proximity of short aminoacylated RNAs led to the synthesis of peptides of random sequence. We postulate that among these emerged a type of peptide(s) capable of stimulating the interaction between specific RNAs and specific amino acids, which we call “bridge peptide” (BP). We conclude that translation should have emerged at the same time when the standard genetic code begun to evolve due to the stabilizing effect on RNA-peptide complexes with the help of BPs. Ribosomes, ribozymes, and the enzyme-directed RNA replication could co-evolve within the same period, as logical outcome of RNA-peptide world without the need of RNA only self-sustained step

An algorithm and application to efficiently analyse DNA fibre data

AbstractThe duplication of genetic information (DNA replication) is central to life. Numerous control mechanisms ensure the exact course of the process during each cell division. Disturbances of DNA replication have severe consequences for the affected cell, and current models link them to cancer development. One of the most accurate methods for studying DNA replication is labelling newly synthesised DNA molecules with halogenated nucleotides, followed by immunofluorescence and microscopy detection, known as DNA fibre labelling. The method allows the registration of the activity of single replication complexes by measuring the length of the “trace” left by each of them. The major difficulty of the method is the labor-intensive analysis, which requires measuring the lengths of a large number of labelled fragments. Recently, the interest in this kind of image analysis has grown rapidly. In this project we have developed an algorithm and a lightweight Java application to automatically analyse single DNA molecule images that we have named “DNA size finder”. DNA size finder significantly simplified the analysis of the experimental data while increasing reliability by the standardised measurement of a greater number of DNA molecules. It is freely available and does not require any paid platforms or services to be used. We hope that the application will facilitate both the study of DNA replication control and the effects of various compounds used in human activity on the process of DNA replication

Interferon-<b>γ</b> as a Potential Inhibitor of SARS-CoV-2 ORF6 Accessory Protein

The ORF6 protein of the SARS-CoV-2 virus plays a crucial role in blocking the innate immune response of the infected cells by inhibiting interferon pathways. Additionally, it binds to and immobilises the RAE1 protein on the cytoplasmic membranes, thereby blocking mRNA transport from the nucleus to the cytoplasm. In all these cases, the host cell proteins are tethered by the flexible C-terminus of ORF6. A possible strategy to inhibit the biological activity of ORF6 is to bind its C-terminus with suitable ligands. Our in silico experiments suggest that hIFNγ binds the ORF6 protein with high affinity, thus impairing its interactions with RAE1 and, consequently, its activity in viral invasion. The in vitro studies reported here reveal a shift of the localisation of RAE1 in ORF6 overexpressing cells upon treatment with hIFNγ from predominantly cytoplasmic to mainly nuclear, resulting in the restoration of the export of mRNA from the nucleus. We also explored the expression of GFP in transfected-with-ORF6 cells by means of fluorescence microscopy and qRT-PCR, finding that treatment with hIFNγ unblocks the mRNA trafficking and reinstates the GFP expression level. The ability of the cytokine to block ORF6 is also reflected in minimising its negative effects on DNA replication by reducing accumulated RNA-DNA hybrids. Our results, therefore, suggest hIFNγ as a promising inhibitor of the most toxic SARS-CoV-2 protein

Antitumor Activity of Bioactive Compounds from Rapana venosa against Human Breast Cell Lines

This study is the first report describing the promising antitumor activity of biologically active compounds isolated from the hemolymph of marine snail Rapana venosa&mdash;a fraction with Mw between 50 and 100 kDa and two structural subunits (RvH1 and RvH2), tested on a panel of human breast cell lines&mdash;six lines of different molecular subtypes of breast cancer MDA-MB-231, MDA-MB-468, BT-474, BT-549, SK-BR-3, and MCF-7 and the non-cancerous MCF-10A. The fraction with Mw 50&ndash;100 kDa (HRv 50&ndash;100) showed good antitumor activity manifested by a significant decrease in cell viability, altered morphology, autophagy, and p53 activation in treated cancer cells. An apparent synergistic effect was observed for the combination of HRv 50&ndash;100 with cis-platin for all tested cell lines. The combination of HRv 50&ndash;100 with cisplatin and/or tamoxifen is three times more effective compared to treatment with classical chemotherapeutics alone. The main proteins in the active fraction, with Mw at ~50 kDa, ~65 kDa, ~100 kDa, were identified by MALDI-MS, MS/MS analyses, and bioinformatics. Homology was established with known proteins with antitumor potential detected in different mollusc species: peroxidase-like protein, glycoproteins Aplysianin A, L-amino acid oxidase (LAAO), and the functional unit with Mw 50 kDa of RvH. Our study reveals new perspectives for application of HRv 50&ndash;100 as an antitumor agent used alone or as a booster in combination with different chemotherapies

Molecular Mechanism of the Anti-Inflammatory Action of Heparin

Our objective is to reveal the molecular mechanism of the anti-inflammatory action of low-molecular-weight heparin (LMWH) based on its influence on the activity of two key cytokines, IFNγ and IL-6. The mechanism of heparin binding to IFNγ and IL-6 and the resulting inhibition of their activity were studied by means of extensive molecular-dynamics simulations. The effect of LMWH on IFNγ signalling inside stimulated WISH cells was investigated by measuring its antiproliferative activity and the translocation of phosphorylated STAT1 in the nucleus. We found that LMWH binds with high affinity to IFNγ and is able to fully inhibit the interaction with its cellular receptor. It also influences the biological activity of IL-6 by binding to either IL-6 or IL-6/IL-6Rα, thus preventing the formation of the IL-6/IL-6Rα/gp130 signalling complex. These findings shed light on the molecular mechanism of the anti-inflammatory action of LMWH and underpin its ability to influence favourably conditions characterised by overexpression of these two cytokines. Such conditions are not only associated with autoimmune diseases, but also with inflammatory processes, in particular with COVID-19. Our results put forward heparin as a promising means for the prevention and suppression of severe CRS and encourage further investigations on its applicability as an anti-inflammatory agent