Decitabine-induced DNA methylation-mediated transcriptomic reprogramming in human breast cancer cell lines; the impact of DCK overexpression

Decitabine (DAC), a DNA methyltransferase (DNMT) inhibitor, is tested in combination with conventional anticancer drugs as a treatment option for various solid tumors. Although epigenome modulation provides a promising avenue in treating resistant cancer types, more studies are required to evaluate its safety and ability to normalize the aberrant transcriptional profiles. As deoxycytidine kinase (DCK)-mediated phosphorylation is a rate-limiting step in DAC metabolic activation, we hypothesized that its intracellular overexpression could potentiate DAC’s effect on cell methylome and thus increase its therapeutic efficacy. Therefore, two breast cancer cell lines, JIMT-1 and T-47D, differing in their molecular characteristics, were transfected with a DCK expression vector and exposed to low-dose DAC (approximately IC20). Although transfection resulted in a significant DCK expression increase, further enhanced by DAC exposure, no transfection-induced changes were found at the global DNA methylation level or in cell viability. In parallel, an integrative approach was applied to decipher DAC-induced, methylation-mediated, transcriptomic reprogramming. Besides large-scale hypomethylation, accompanied by up-regulation of gene expression across the entire genome, DAC also induced hypermethylation and down-regulation of numerous genes in both cell lines. Interestingly, TET1 and TET2 expression halved in JIMT-1 cells after DAC exposure, while DNMTs’ changes were not significant. The protein digestion and absorption pathway, containing numerous collagen and solute carrier genes, ranking second among membrane transport proteins, was the top enriched pathway in both cell lines when hypomethylated and up-regulated genes were considered. Moreover, the calcium signaling pathway, playing a significant role in drug resistance, was among the top enriched in JIMT-1 cells. Although low-dose DAC demonstrated its ability to normalize the expression of tumor suppressors, several oncogenes were also up-regulated, a finding, that supports previously raised concerns regarding its broad reprogramming potential. Importantly, our research provides evidence about the involvement of active demethylation in DAC-mediated transcriptional reprogramming.publishedVersio

Bratislava Statement: consensus recommendations for improving pancreatic cancer care

Pancreatic cancer is one of the most lethal tumours, and it is the fourth cause of cancer death in Europe. Despite its important public health impact, no effective treatments exist, nor are there high-visibility research efforts to improve care. This alarming situation is emblematic of a larger group of cancer diseases, known as neglected cancers. To address the impact of these diseases, the European Commission-supported Innovative Partnership for Action Against Cancer launched a multi-stakeholder initiative to determine key steps that healthcare systems can rapidly implement to improve their response. A working group comprising 20 representatives from European medical societies, patient associations, cancer plan organisations and other relevant European healthcare stakeholders was organised. A consensus process based on the results of different studies, discussion of research outcomes, and development and endorsement of draft statements resulted in 22 consensus recommendations (the Bratislava Statement). The statement argues that substantial improvements can be achieved in patient outcomes by centralising pancreatic cancer care around state-of-the-art reference centres, staffed by expert multidisciplinary teams capable of providing high-quality care. This organisational model requires a specific care framework encompassing primary, palliative and survivorship care, and a policy environment prioritising the use of quality criteria and performance assessments as well as research investments dedicated to prevention, risk prediction, early detection and diagnosis. In order to address the challenges posed by neglected cancers in general and pancreatic cancer in particular, a specific control strategy tailored to this reality is required

Decitabine potentiates efficacy of doxorubicin in a preclinical trastuzumab-resistant HER2-positive breast cancer models

Acquired drug resistance and metastasis in breast cancer (BC) are coupled with epigenetic deregulation of gene expression. Epigenetic drugs, aiming to reverse these aberrant transcriptional patterns and sensitize cancer cells to other therapies, provide a new treatment strategy for drug-resistant tumors. Here we investigated the ability of DNA methyltransferase (DNMT) inhibitor decitabine (DAC) to increase the sensitivity of BC cells to anthracycline antibiotic doxorubicin (DOX). Three cell lines representing different molecular BC subtypes, JIMT-1, MDA-MB-231 and T-47D, were used to evaluate the synergy of sequential DAC + DOX treatment in vitro. The cytotoxicity, genotoxicity, apoptosis, and migration capacity were tested in 2D and 3D cultures. Moreover, genome-wide DNA methylation and transcriptomic analyses were employed to understand the differences underlying DAC responsiveness. The ability of DAC to sensitize trastuzumab-resistant HER2-positive JIMT-1 cells to DOX was examined in vivo in an orthotopic xenograft mouse model. DAC and DOX synergistic effect was identified in all tested cell lines, with JIMT-1 cells being most sensitive to DAC. Based on the whole-genome data, we assume that the aggressive behavior of JIMT-1 cells can be related to the enrichment of epithelial-to-mesenchymal transition and stemness-associated pathways in this cell line. The four-week DAC + DOX sequential administration significantly reduced the tumor growth, DNMT1 expression, and global DNA methylation in xenograft tissues. The efficacy of combination therapy was comparable to effect of pegylated liposomal DOX, used exclusively for the treatment of metastatic BC. This work demonstrates the potential of epigenetic drugs to modulate cancer cells' sensitivity to other forms of anticancer therapy.publishedVersio

Nanomedicine and epigenetics: New alliances to increase the odds in pancreatic cancer survival

Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest cancers worldwide, primarily due to its robust desmoplastic stroma and immunosuppressive tumor microenvironment (TME), which facilitate tumor progression and metastasis. In addition, fibrous tissue leads to sparse vasculature, high interstitial fluid pressure, and hypoxia, thereby hindering effective systemic drug delivery and immune cell infiltration. Thus, remodeling the TME to enhance tumor perfusion, increase drug retention, and reverse immunosuppression has become a key therapeutic strategy. In recent years, targeting epigenetic pathways has emerged as a promising approach to overcome tumor immunosuppression and cancer progression. Moreover, the progress in nanotechnology has provided new opportunities for enhancing the efficacy of conventional and epigenetic drugs. Nano-based drug delivery systems (NDDSs) offer several advantages, including improved drug pharmacokinetics, enhanced tumor penetration, and reduced systemic toxicity. Smart NDDSs enable precise targeting of stromal components and augment the effectiveness of immunotherapy through multiple drug delivery options. This review offers an overview of the latest nano-based approaches developed to achieve superior therapeutic efficacy and overcome drug resistance. We specifically focus on the TME and epigenetic-targeted therapies in the context of PDAC, discussing the advantages and limitations of current strategies while highlighting promising new developments. By emphasizing the immense potential of NDDSs in improving therapeutic outcomes in PDAC, our review paves the way for future research in this rapidly evolving field.This research was funded by the European Union’s Horizon 2020 research and innovation program under grant agreement No 857381/VISION, the Spanish Biomedical Research Network in Cancer CIBERONC (CB16/12/00446), from the Slovak Research and Development Agency (APVV-21-0197, APVV-20-0143) and TRANSCAN-2 Program ERA-NET JTC 2017 “Translational research on rare cancers” within the project NExT.Peer reviewe

Author Correction: DNA damage in circulating leukocytes measured with the comet assay may predict the risk of death (Scientific Reports, (2021), 11, 1, (16793), 10.1038/s41598-021-95976-7)

Link to the corrected article: [https://farfar.pharmacy.bg.ac.rs/handle/123456789/3944

DNA damage in circulating leukocytes measured with the comet assay may predict the risk of death

The comet assay or single cell gel electrophoresis, is the most common method used to measure strand breaks and a variety of other DNA lesions in human populations. To estimate the risk of overall mortality, mortality by cause, and cancer incidence associated to DNA damage, a cohort of 2,403 healthy individuals (25,978 person-years) screened in 16 laboratories using the comet assay between 1996 and 2016 was followed-up. Kaplan–Meier analysis indicated a worse overall survival in the medium and high tertile of DNA damage (p < 0.001). The effect of DNA damage on survival was modelled according to Cox proportional hazard regression model. The adjusted hazard ratio (HR) was 1.42 (1.06–1.90) for overall mortality, and 1.94 (1.04–3.59) for diseases of the circulatory system in subjects with the highest tertile of DNA damage. The findings of this study provide epidemiological evidence encouraging the implementation of the comet assay in preventive strategies for non-communicable diseases.This article has been corrected. Link to the correction: [https://farfar.pharmacy.bg.ac.rs/handle/123456789/3975

The Metastatic Process through the Eyes of Epigenetic Regulation: A Promising Horizon for Cancer Therapy

Genetic aberrations, including chromosomal rearrangements, loss or amplification of DNA, and point mutations, are major elements of cancer development [...

Global DNA methylation and physical fitness of elderly athletes with lifelong endurance activity

Background: Level of Global DNA methylation is associated with many diseases and the influence of physical activity is being investigated by several research groups. The aim of our study was to assess the effect of lifetime endurance physical activity on global DNA methylation, physical fitness and body composition. Methods: A total of 31 elderly males were involved in the study, divided into two groups based on differences in physical activity. The first group consisted of 18 volunteers with lifetime endurance activity (mean age: 65.1 ± 3.3 yr.; height: 174.8 ± 4.9; weight: 81.5 ± 6,1 kg; BMI: 24.2 ± 1.1). The control group consisted of thirteen elderly individuals with a sedentary lifestyle (mean age: 64.8 ± 3.1 yr.; height: 176.5 ± 5.5; weight: 87.9 ± 10.1 kg; BMI: 27.8 ± 2.9). Quantification of global DNA methylation was performed in DNA isolated from peripheral blood mononucleated cells by LINE-1 pyrosequencing. Results: Elderly individuals with lifetime endurance activity had a better level of physical fitness VO2max on average 30 % (35.7 ± 10.6 vs. 31.9 ± 7,7 ml.kg-1.min-1, p <.01) and lower mean body fat content (17.46 ± 2.52 vs. 27.8 ± 2.9 %, p < .01). Global DNA methylation did not differ between studied groups (81.1 ± 2.1 vs. 80.5 ± 1.6 %). Conclusion: Better level of physical fitness does not influence the level of the global DNA methylation in peripheral blood mononuclear cells significantly. For future research we recommended to observe DNA methylation changes in specific tissues (e.g. skeletal muscle fibres).This study was funded by the Ministry of Education, Science, Research and Sport of the Slovak Republic, grant APVV-17-0099 and VEGA 2/0052/18

Targeting Epigenetic Modifications in Uveal Melanoma

Uveal melanoma (UM), the most common intraocular malignancy in adults, is a rare subset of melanoma. Despite effective primary therapy, around 50% of patients will develop the metastatic disease. Several clinical trials have been evaluated for patients with advanced UM, though outcomes remain dismal due to the lack of efficient therapies. Epigenetic dysregulation consisting of aberrant DNA methylation, histone modifications, and small non-coding RNA expression, silencing tumor suppressor genes, or activating oncogenes, have been shown to play a significant role in UM initiation and progression. Given that there is no evidence any approach improves results so far, adopting combination therapies, incorporating a new generation of epigenetic drugs targeting these alterations, may pave the way for novel promising therapeutic options. Furthermore, the fusion of effector enzymes with nuclease-deficient Cas9 (dCas9) in clustered regularly interspaced short palindromic repeats (CRISPR) associated protein 9 (Cas9) system equips a potent tool for locus-specific erasure or establishment of DNA methylation as well as histone modifications and, therefore, transcriptional regulation of specific genes. Both, CRISPR-dCas9 potential for driver epigenetic alterations discovery, and possibilities for their targeting in UM are highlighted in this review

Suicide-Gene-Modified Extracellular Vesicles of Human Primary Uveal Melanoma in Future Therapies

Extracellular vesicles secreted from uveal melanoma (UM) cells are involved in the establishment of the premetastatic niche and display transforming potential for the formation of metastases, preferentially in the liver. In this study, we cultivated human primary UM cells and uveal melanoma-associated fibroblasts in vitro to be transduced by infection with a retrovirus containing the suicide gene—fused yeast cytosine deaminase::uracil phospho-ribosyl transferase (yCD::UPRT). A homogenous population of yCD::UPRT-UM cells with the integrated provirus expressed the gene, and we found it to continuously secrete small extracellular vesicles (sEVs) possessing mRNA of the suicide gene. The yCD::UPRT-UM-sEVs were internalized by tumor cells to the intracellular conversion of the prodrug 5-fluorocytosine (5-FC) to the cytotoxic drug 5-fluorouracil (5-FU). The host range of the yCD::UPRT-UM-sEVs was not limited to UMs only. The yCD::UPRT-UM-sEVs inhibited the growth of the human cutaneous melanoma cell line A375 and uveal melanoma cell line MP38, as well as other primary UMs, to various extents in vitro. The yCD::UPRT-UM-sEVs hold the therapeutic and prophylactic potential to become a therapeutic drug for UM. However, the use of yCD::UPRT-UM-sEVs must first be tested in animal preclinical studies