Ewelina Synowiec

The journal retracts the article titled, “The Impact of Chronic Mild Stress and Agomelatine Treatment on the Expression Level and Methylation Status of Genes Involved in Tryptophan Catabolic Pathway in PBMCs and Brain Structures”

Ochratoxin A (OTA) is a widespread mycotoxin with documented nephrotoxic, hepatotoxic, immunotoxic, and carcinogenic effects, while its role in hematological malignancies and immune cells remains insufficiently defined. This study examined the cytotoxic and pro-apoptotic OTA activity in three human leukemia cell lines (CCRF-CEM, K-562, HL-60) and in peripheral blood mononuclear cells (PBMCs) from healthy donors. Cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and trypan blue assays, mitochondrial membrane potential (ΔΨM) was assessed with JC-1 dye, caspase-3/7 activity was measured by flow cytometry, and the expression of apoptosis-related genes was analyzed by RT-qPCR. OTA did not significantly affect viability, mitochondrial function, or caspase activity in leukemia cell lines, suggesting relative resistance to OTA-induced apoptosis. In contrast, PBMCs exhibited clear dose- and time-dependent sensitivity, manifested by reduced viability, ΔΨM, caspase-3/7 activation, and transcriptional changes consistent with intrinsic apoptosis, including decreased BCL-2 (anti-apoptotic) and increased BAX (pro-apoptotic), APAF1 (apoptosome component), CASP3, and CASP9 (executioner and initiator caspases) expression. These findings demonstrate that OTA selectively targets healthy immune cells rather than leukemia cells, highlighting its pronounced immunotoxic risk and the importance of caution when considering its effect in a hematological context. Although limited to in vitro models, this study underscores the necessity of further research to clarify the molecular basis of differential OTA sensitivity and its contribution to immunosuppression and hematological disease.

Azurin is a copper-containing redox protein naturally produced by Pseudomonas aeruginosa, which has shown promising activity against human cancer cells by inducing apoptosis. The present study describes the design of a recombinant vector, pT7-MAT-Tag-2-Azu, for azurin production in E. coli cells. The cytotoxic effects of purified azurin were tested on three breast cancer cell lines (MCF-7, MDA-MB-231, and HCC38) and a normal breast epithelial cell line (MCF10A) using the MTT assay. The results showed cytotoxicity against cancer cell lines with minimal effects on normal cells. Further analysis showed that azurin induced apoptosis through mitochondrial pathways, as evidenced by increased expression of apoptosis-related genes (Bax, TP53, Apaf-1, caspase-3, -8, -9) and their corresponding proteins, elevated levels of reactive oxygen species (ROS), and DNA damage, mitochondrial membrane potential (MMP), or brine shrimp lethality assay. Furthermore, in silico molecular docking, simulations predicted a stable, electrostatically driven interaction between azurin and the p53 protein, providing a structural basis for its mechanism of action. These findings suggest that recombinant azurin may serve as a potential therapeutic agent for breast cancer after further multifaceted research.

DNA repair proteins became the popular targets in research on cancer treatment. In our studies we hypothesized that inhibition of DNA polymerase theta (Polθ) and its combination with Poly (ADP-ribose) polymerase 1 (PARP1) or RAD52 inhibition and the alkylating drug temozolomide (TMZ) has an anticancer effect on glioblastoma cells (GBM21), whereas it has a low impact on normal human astrocytes (NHA). The effect of the compounds was assessed by analysis of cell viability, apoptosis, proliferation, DNA damage and cell cycle distribution, as well as gene expression. The main results show that Polθ inhibition causes a significant decrease in glioblastoma cell viability. It induces apoptosis, which is accompanied by a reduction in cell proliferation and DNA damage. Moreover, the effect was stronger when dual inhibition of Polθ with PARP1 or RAD52 was applied, and it is further enhanced by addition of TMZ. The impact on normal cells is much lower, especially when considering cell viability and DNA damage. In conclusion, we would like to highlight that Polθ inhibition used in combination with PARP1 or RAD52 inhibition has great potential to kill glioblastoma cells, and shows a synthetic lethal effect, while sparing normal astrocytes.

Plectranthus scutellarioides (L.) R.Br. is a medicinal plant that has long been used in traditional medicine to treat conditions such as abscesses, ulcers, and ear and eye infections. It is known to have a wide range of biological properties, such as antibacterial, antioxidant, antifungal, anti-inflammatory, anti-diabetic and anti-cancer effects. In this study, we established in vitro cultures from both the aerial parts and roots of Plectranthus scutellarioides. Subsequently, we compared the basic phytochemical profile of the obtained extracts and conducted a biological analysis to assess their potential for inducing apoptosis in breast (MCF-7) and lung (A549) cancer cells. Phytochemical analysis by HPLC-MS revealed the presence of compounds belonging to phenolic acids (ferulic, syringic, vanillic, rosmarinic, chlorogenic, caffeic, coumaric, dihydroxybenzoic acids), flavonoids (eriodyctiol and cirsimaritin), and terpenes such as 6,11,12,14,16-Pentahydroxy-3,17diacetyl-8,11,13-abietatrien-7-one, 6,11,12,14,16-Pentahydroxy-3,17-diacetyl5,8,11,13-abietatetraen-7-one, and 3,6,12-Trihydroxy-2-acetyl-8,12-abietadien7,11,14-trione. The results show that both extracts have a cytotoxic and genotoxic effect against MCF-7 and A549 cancer cells, with a different degree of sensitivity. It was also shown that both extracts can induce apoptosis by altering the expression of apoptotic genes (Bax, Bcl-2, TP53, Fas, and TNFSF10), reducing mitochondrial membrane potential, increasing ROS levels, and increasing DNA damage. In addition, it has been shown that the tested extracts can alter blood coagulation parameters. Our results indicate that extracts from in vitro cultures of Plectranthus scutellarioides aerial parts and roots have promising therapeutic application, but further research is needed to better understand the mechanisms of their action in the in vitro model.

One of the key features of major depressive disorder (MDD, depression) is increased oxidative stress manifested by elevated levels of mtROS, a hallmark of mitochondrial dysfunction, which can arise from mitochondrial DNA (mtDNA) damage. Thus, the current study explores possibility that the single-nucleotide polymorphisms (SNPs) of genes encoding the three enzymes that are thought to be implicated in the replication, repair or degradation of mtDNA, i.e., POLG, ENDOG and EXOG, have an impact on the occurrence, onset, severity and treatment of MDD. Five SNPs were selected: EXOG c.-188T > G (rs9838614), EXOG c.*627G > A (rs1065800), POLG c.-1370T > A (rs1054875), ENDOG c.-394T > C (rs2977998) and ENDOG c.-220C > T (rs2997922), while genotyping was performed on 538 DNA samples (277 cases and 261 controls) using TaqMan probes. All SNPs of EXOG and ENDOG modulated the risk of depression, but the strongest effect was observed for rs1065800, while rs9838614 and rs2977998 indicate that they might influence the severity of symptoms, and, to a lesser extent, treatment effectiveness. Although the SNP located in POLG did not affect occurrence of the disease, the result suggests that it may influence the onset and treatment outcome. These findings further support the hypothesis that mtDNA damage and impairment in its metabolism play a crucial role not only in the development, but also in the treatment of depression.

T-2 mycotoxin is the most potent representative of the trichothecene group A and is produced by various Fusarium species, including F. sporotrichioides, F. poae, and F. acuminatum. T-2 toxin has been reported to have toxic effects on various tissues and organs, and humans and animals alike suffer a variety of pathological conditions after consumption of mycotoxin-contaminated food. The T-2 toxin’s unique feature is dermal toxicity, characterized by skin inflammation. In this in vitro study, we investigated the molecular mechanism of T-2 toxin-induced genotoxicity in the human skin fibroblast—Hs68 cell line. For the purpose of investigation, the cells were treated with T-2 toxin in 0.1, 1, and 10 μM concentrations and incubated for 24 h and 48 h. Nuclear DNA (nDNA) is found within the nucleus of eukaryotic cells and has a double-helix structure. nDNA encodes the primary structure of proteins, consisting of the basic amino acid sequence. The alkaline comet assay results showed that T-2 toxin induces DNA alkali-labile sites. The DNA strand breaks in cells, and the DNA damage level is correlated with the increasing concentration and time of exposure to T-2 toxin. The evaluation of nDNA damage revealed that exposure to toxin resulted in an increasing lesion frequency in Hs68 cells with HPRT1 and TP53 genes. Further analyses were focused on mRNA expression changes in two groups of genes involved in the inflammatory and repair processes. The level of mRNA increased for all examined inflammatory genes (TNF, INFG, IL1A, and IL1B). In the second group of genes related to the repair process, changes in expression induced by toxin in genes—LIG3 and APEX were observed. The level of mRNA for LIG3 decreased, while that for APEX increased. In the case of LIG1, FEN, and XRCC1, no changes in mRNA level between the control and T-2 toxin probes were observed. In conclusion, the results of this study indicate that T-2 toxin shows genotoxic effects on Hs68 cells, and the molecular mechanism of this toxic effect is related to nDNA damage.