tion of the targeted messenger RNA (mRNA) almost completely. 19,25 This regulation ensures accuracy and robustness by repressing the expression of mRNAs that linger from previous cell states or the products of leaky transcription. 25

No abstract

Background:Cisplatin cures over 80% of testicular germ cell tumours (TGCTs), and nucleotide-excision repair (NER) modifies the sensitivity to cisplatin. We explored the association between NER proteins and their polymorphisms with cisplatin sensitivity (CPS) and overall survival (OS) of patients with non-seminomatous (ns)-TGCTs.Methods:The expression of ERCC1 and XPA and the presence of γH2AX were evaluated in cancer cell lines and in fresh ns-TGCTs. The ERCC1 protein was also determined in ns-TGCTs. The differences between CPS and non-CPS cell lines and patients were analysed by Student's t- or χ2-tests. The differences in OS were analysed using the log-rank test, and the hazard ratios (HRs) were calculated using the Cox model.Results:High ERCC1 expression was observed in the non-CPS cells, and both ERCC1 and γH2AX expressions were augmented after cisplatin treatment. Increased ERCC1 expression was also identified in non-CPS patients. Neither polymorphism was associated with either CPS or OS. The presence of ERCC1 was associated with non-CPS (P=0.05) and adjusted in the prognosis groups. The HR in ERCC1-negative and non-CPS patients was >14.43, and in ERCC1-positive and non-CPS patients the HR was >11.86 (P<0.001).Conclusions:High levels of ERCC1 were associated with non-CPS, suggesting that ERCC1 could be used as a potential indicator of the response to cisplatin and prognosis in ns-TGCTs.

COVID-19 is an infection caused by SARS-CoV-2 (Severe Acute Respiratory Syndrome coronavirus 2), which has caused a global outbreak. Current research efforts are focused on the understanding of the molecular mechanisms involved in SARS-CoV-2 infection in order to propose drug-based therapeutic options. Transcriptional changes due to epigenetic regulation are key host cell responses to viral infection and have been studied in SARS-CoV and MERS-CoV; however, such changes are not fully described for SARS-CoV-2. In this study, we analyzed multiple transcriptomes obtained from cell lines infected with MERS-CoV, SARS-CoV, and SARS-CoV-2, and from COVID-19 patient-derived samples. Using integrative analyses of gene co-expression networks and de-novo pathway enrichment, we characterize different gene modules and protein pathways enriched with Transcription Factors or Epifactors relevant for SARS-CoV-2 infection. We identified EP300, MOV10, RELA, and TRIM25 as top candidates, and more than 60 additional proteins involved in the epigenetic response during viral infection that has therapeutic potential. Our results show that targeting the epigenetic machinery could be a feasible alternative to treat COVID-19.

BackgroundIn cancer cells, transcriptional gene silencing has been associated with genetic and epigenetic defects. The disruption of DNA methylation patterns and covalent histone marks has been associated with cancer development. Until recently, microRNA (miRNA) gene silencing was not well understood. In particular, miR-125b1 has been suggested to be an miRNA with tumor suppressor activity, and it has been shown to be deregulated in various human cancers. In the present study, we evaluated the DNA methylation at the CpG island proximal to the transcription start site of miR-125b1 in cancer cell lines as well as in normal tissues and gynecological tumor samples. In addition, we analyzed the association of CTCF and covalent histone modifications at the miR-125b1 locus.MethodsTo assess the DNA methylation status of the miR-125b1, genomic DNA was transformed with sodium bisulfite, and then PCR-amplified with modified primers and sequenced. The miR-125b1 gene expression was analyzed by qRT-PCR using U6 as a control for constitutive gene expression. CTCF repressive histone marks abundance was evaluated by chromatin immunoprecipitation assays.ResultsThe disruption of CTCF in breast cancer cells correlated with the incorporation of repressive histone marks such H3K9me3 and H3K27me3 as well as with aberrant DNA methylation patterns. To determine the effect of DNA methylation at the CpG island of miR-125b1 on the expression of this gene, we performed a qRT-PCR assay. We observed a significant reduction on the expression of miR-125b1 in cancer cells in comparison with controls, suggesting that DNA methylation at the CpG island might reduce miR-125b1 expression. These effects were observed in other gynecological cancers, including ovarian and cervical tumors.ConclusionsA reduction of miR-125b1 expression in cancers, correlated with methylation, repressive histone marks and loss of CTCF binding at the promoter region.

No abstract

Prostate cancer is the most common cancer in men and the second leading cause of cancer-related deaths. The most used biomarker to detect prostate cancer is Prostate Specific Antigen (PSA), whose levels are measured in serum. However, it has been recently established that molecular markers of cancer should not be based solely on genes and proteins but should also reflect other genomic traits; long non-coding RNAs (lncRNAs) serve this purpose. lncRNAs are transcripts of >200 bases that do not encode proteins and that have been shown to display abnormal expression profiles in different types of cancer. Experimental studies have highlighted lncRNAs as potential biomarkers for prognoses and treatments in patients with different types of cancer, including prostate cancer, where the PCA3 lncRNA is currently used as a diagnostic tool and management strategy. With the development of genomic technologies, particularly next-generation sequencing (NGS), several other lncRNAs have been linked to prostate cancer and are currently under validation for their medical use. In this review, we will discuss different strategies for the discovery of novel lncRNAs that can be evaluated as prognostic biomarkers, the clinical impact of these lncRNAs and how lncRNAs can be used as potential therapeutic targets.

Extrasynaptic α5‐subunit containing GABAA (α5‐GABAA) receptors participate in chronic pain. Previously, we reported a sex difference in the action of α5‐GABAA receptors in dysfunctional pain. However, the underlying mechanisms remain unknown. The aim of this study was to examine this sexual dimorphism in neuropathic rodents and the mechanisms involved. Female and male Wistar rats or ICR mice were subjected to nerve injury followed by α5‐GABAA receptor inverse agonist intrathecal administration, L‐655,708. The drug produced an antiallodynic effect in nerve‐injured female rats and mice, and a lower effect in males. We hypothesized that changes in α5‐GABAA receptor, probably influenced by hormonal and epigenetic status, might underlie this sex difference. Thus, we performed qPCR and western blot. Nerve injury increased α5‐GABAA mRNA and protein in female dorsal root ganglia (DRG) and decreased them in DRG and spinal cord of males. To investigate the hormonal influence over α5‐GABAA receptor actions, we performed nerve injury to ovariectomized rats and reconstituted them with 17β‐estradiol (E2). Ovariectomy abrogated L‐655,708 antiallodynic effect and E2 restored it. Ovariectomy decreased α5‐GABAA receptor and estrogen receptor α protein in DRG of neuropathic female rats, while E2 enhanced them. Since DNA methylation might contribute to α5‐GABAA receptor down‐regulation in males, we examined CpG island DNA methylation of α5‐GABAA receptor coding gene through pyrosequencing. Nerve injury increased methylation in male, but not female rats. Pharmacological inhibition of DNA methyltransferases increased α5‐GABAA receptor and enabled L‐655,708 antinociceptive effect in male rats. These results suggest that α5‐GABAA receptor is a suitable target to treat chronic pain in females.