The development of malignant tumors is caused by a complex combination of genetic mutations and epigenetic alterations, the latter of which are induced by either external environmental factors or signaling disruption following genetic mutations. Some types of cancer demonstrate a significant increase in epigenetic enzymes, and targeting these epigenetic alterations represents a compelling strategy to reverse cell transcriptome to the normal state, improving chemotherapy response. Curaxin CBL0137 is a new potent anticancer drug that has been shown to activate epigenetically silenced genes. However, its detailed effects on the enzymes of the epigenetic system of transcription regulation have not been studied. Here, we report that CBL0137 inhibits the expression of DNA methyltransferase DNMT3a in HeLa TI cells, both at the level of mRNA and protein, and it decreases the level of integral DNA methylation in Ca Ski cells. For the first time, it is shown that CBL0137 decreases the level of BET family proteins, BRD2, BRD3, and BRD4, the key participants in transcription elongation, followed by the corresponding gene expression enhancement. Furthermore, we demonstrate that CBL0137 does not affect the mechanisms of histone acetylation and methylation. The ability of CBL0137 to suppress DNMT3A and BET family proteins should be taken into consideration when combined chemotherapy is applied. Our data demonstrate the potential of CBL0137 to be used in the therapy of tumors with corresponding aberrant epigenetic profiles.

Dithiocarbamate pesticides possess a diverse array of molecular mechanisms, making them multifunctional substances

One of the factors associated with increased morbidity of malignant neoplasms is environmental pollution with cancerogenic compounds including pesticides. Until recently, stable organic pollutant insecticide dichlorodiphenyltrichloroethane (DDT) was the single tool for fighting malaria carriers. Despite vast evidence of its negative effect on human health, DDT is still used in some countries.Aim. To perform a comprehensive analysis of the dynamics of DDT pesticide use and the consequences of its use on the global healthcare as well as to investigate the mechanism of its action on the human body including the endocrine system and cancerogenic effects.The review was composed using the PubMed (2853 publications), Elsevier (3139 publications), eLibrary (784 publications) biomedical literature databases. Full-text articles were retrieved through PubMed Central (PMC), Science Direct, Research Gate, CyberLeninka electronic resources.

Breast cancer (BC) is a complex disease driven by a combination of genetic mutations and epigenetic modifications. In particular, the overexpression of BET family proteins (BETs) has emerged as a key epigenetic aberration contributing to BC pathogenesis. CBL0137 (CBL), a small-molecule compound, has shown promise as an inhibitor of BETs in HeLa TI cells. In this study, we aimed to assess the anticancer effects of CBL in vitro and evaluate its impact on the expression of BETs in BC cells. Cells of three subtypes of BC (MCF7, MDA-MB-231, SKBR3) were used in this study. Cytotoxic effects were analyzed using the MTT assay. Effects on cell cycle and apoptosis were assessed using FACS with PI and FITC-Annexin staining. The level of BETs (BRD2, BRD3, BRD4) was determined by Western blotting. CBL demonstrated a significant reduction in BС cell viability with an IC50 value of approximately 1 μM for all cell lines after 72h of exposure and 20 μM after 24h. CBL treatment resulted in an increase in cells in the G2/M phase in MCF7 and SKBR3 cells after 24h and 72h of action, as well as in MDA-MB-231 cells after 24h. In MCF7 cells, the influence of CBL led to apoptotic changes characterized by a slight elevation in the early apoptotic population. Treatment of MDA-MB-231 cells with CBL resulted in a decrease in the expression of BRD2, BRD3, and BRD4 proteins, while treatment of MCF7 cells led to a reduction in BRD3 and BRD4 protein levels. No significant changes in the amount of BET proteins were observed in SKBR3 cells. In conclusion, the presented data offer valuable insights into the mechanisms of action of CBL, providing a basis for further investigation into its therapeutic potential in BC treatment. This research was funded by the RSF (no. 21-75-10163).

Introduction. Cancer remains a major cause of mortality worldwide, with adverse environmental factors such as pesticides contributing significantly to its development. Despite the widespread use of various pesticides, the molecular mechanisms underlying their actions and carcinogenic potential have been studied for only a limited number of models, especially in normal human cells.Aim. To study the molecular effects of pesticides carbaryl, chlorpyrifos, mancozeb, thiram, and pendimethalin in nonmalignant HaCaT and MCF10A cells.Materials and methods. Non-toxic concentrations of pesticides were determined using the MTT assay. Genotoxicity was analyzed by the comet assay. Proliferative potential was assessed by clonogenic assay. Changes in the expression of genes associated with carcinogenesis were evaluated by real-time polymerase chain reaction.Results. Carbaryl caused DNA damage in MCF10A cells, promoted proliferation in both cell lines during clonogenic assay, as well as caused activation of biotransformation genes (AHR, GSTA4) in MCF10A cells, repression (CYP1B1, GSTA4) genes in HaCaT cells and lowered expression of inflammation genes (IL1a, IL1b, PTGES, IFNGR1). Chlorpyrifos did not have genotoxic effect and did not affect clonogenicity but caused induction of biotransformation (CYP1A1, CYP1B1), inflammation (IL1b, PTGES) genes, and genes BCL2 and DNMTs. Mancozeb and thiram did not show genotoxicity in HaCaT and MCF10A cells but activated individual repair genes (ATR/ATM). Thiram stimulated HaCaT cell proliferation in clonogenic assay, and mancozeb activated expression of proliferation regulation genes (CCND2, CCNE1, Ki-67) but did not affect colony growth; both fungicides decreased expression of inflammation genes (COX2, IL1a, IL1b). Pendimethalin caused DNA damage and activation of repair genes (ATR, GADD45a, PCNA) in both cell lines, as well as decreased expression of GLUT3 in HaCaT cells and induced expression of CYP1A1 in HaCaT cells and CYP1B1 in MCF10A cells.Conclusion. In this study, we performed a comprehensive assessment of the effects of pesticides on normal human cells. Our results indicate that pendimethalin, chlorpyrifos, and carbaryl exert the most procarcinogenic effect.

Introduction. Breast cancer (BC) represents a group of malignant neoplasms with various molecular profiles, which are characterized by aberrations in the mechanisms of epigenetic transcription regulation. One of these disruptions associated with a worse prognosis is the overexpression of the BET protein family, responsible for the interaction of transcription factors with histone-rich acetylated regions. Previously, for the multitargeted epigenetically active agent curaxin CBL0137 (CBL), we have shown the ability to inhibit the expression of BRD2, BRD3, BRD4 proteins in HeLa TI cells and BRD3, BRD4 proteins in BC cells.Aim. To analyze the molecular mechanisms of CBL0137 action on BC cells in vitro, including: 1) assessment of cytotoxicity, 2) analysis of the effect on the cell cycle, 3) assessment of the ability to trigger apoptosis, 4) cause DNA damage, and 5) analyze the effect on the expression of genes involved in proliferation, apoptosis and repair processes.Materials and methods. The cytotoxicity of CBL on BC cells (MCF7, MDA-MB-231, SKBR3) was assessed using the MTT assay. The effect of the agent on the cell cycle and activation of apoptosis was analyzed by flow cytometry. Analysis of DNA damage under the action of CBL was performed using the comet assay. Changes in the expression of genes associated with proliferation, repair and apoptosis were evaluated using real-time polymerase chain reaction.Results. The half maximal inhibitory concentration (IC50) on BC cells under the action of CBL0137 were 1 μM at 72-hour exposure, 14–25 μM at 24-hour. Curaxin CBL (0.5 and 1 μM) caused G2/M cell cycle arrest, and also triggered apoptosis in all cell lines. Under the action of 1 μM CBL, an increase in the degree of DNA damage in MCF7 and SKBR3 cells was recorded, and under the action of both concentrations in MDA-MB-231 cells. The gene expression profile involved in proliferation also corresponded to the arrest in the G2/M phase of the cell cycle. Also, under the action of CBL, the activation of p53-dependent repair genes occurred. An increase in the expression of pro-apoptotic and a decrease in anti-apoptotic genes was shown.Conclusion. Curaxin CBL0137 showed differential effects on molecular processes in BC cells. We have identified a cytostatic effect of the compound, confirmed at various molecular levels. The data obtained indicate the ability of CBL0137 to inhibit tumor processes in BC cells, which makes it a potentially interesting agent for combination therapy.