Structure-based modeling to assess binding and endocrine disrupting potential of polycyclic aromatic hydrocarbons in Daniorerio.

Environmental contaminants, such as polycyclic aromatic hydrocarbons (PAHs), have raised concerns regarding their potential endocrine-disrupting effects on aquatic organisms, including fish. In this study, molecular docking and molecular dynamics techniques were employed to evaluate the endocrine-disrupting potential of PAHs in zebrafish, as a model organism. A virtual screening with 72 PAHs revealed a correlation between the number of PAH aromatic rings and their binding affinity to proteins involved in endocrine regulation. Furthermore, PAHs with the highest binding affinities for each protein were identified: cyclopenta[cd]pyrene for AR (-9.7 kcal/mol), benzo(g)chrysene for ERα (-11.5 kcal/mol), dibenzo(a,e)pyrene for SHBG (-8.7 kcal/mol), dibenz(a,h)anthracene for StAR (-11.2 kcal/mol), and 2,3-benzofluorene for TRα (-9.8 kcal/mol). Molecular dynamics simulations confirmed the stability of the protein-ligand complexes formed by the PAHs with the highest binding affinities throughout the simulations. Additionally, the effectiveness of the protocol used in this study was demonstrated by the receiver operating characteristic curve (ROC) analysis, which effectively distinguished decoys from true ligands. Therefore, this research provides valuable insights into the endocrine-disrupting potential of PAHs in fish, highlighting the importance of assessing their impact on aquatic ecosystems.

Exploring the endocrine disrupting potential of a complex mixture of PAHs in the estrogen pathway in Oreochromis niloticus hepatocytes.

This study aimed to investigate the toxicity and endocrine disrupting potential of a complex mixture of polycyclic aromatic hydrocarbons (PAHs) in the estrogen pathway using hepatocytes of Nile tilapia Oreochromis niloticus, the hepatocytes were exposed to various concentrations of the PAH mixture, and multiple endpoints were evaluated to assess their effects on cell viability, gene expression, oxidative stress markers, and efflux activity. The results revealed that the PAH mixture had limited effects on hepatocyte metabolism and cell adhesion, as indicated by the non-significant changes observed in MTT metabolism, neutral red retention, and crystal violet staining. However, significant alterations were observed in the expression of genes related to the estrogen pathway. Specifically, vitellogenin (vtg) exhibited a substantial increase of approximately 120% compared to the control group. Similarly, estrogen receptor 2 (esr2) showed a significant upregulation of approximately 90%. In contrast, no significant differences were observed in the expression of estrogen receptor 1 (esr1) and the G protein-coupled estrogen receptor 1 (gper1). Furthermore, the PAH mixture elicited complex responses in oxidative stress markers. While reactive oxygen species (ROS) and reactive nitrogen species (RNS) levels remained unchanged, the activity of catalase (Cat) was significantly reduced, whereas superoxide dismutase (Sod) activity, glutathione S-transferase (Gst) activity, and non-protein thiols levels were significantly elevated. In addition, the PAH mixture significantly influenced efflux activity, as evidenced by the increased efflux of rhodamine and calcein, indicating alterations in multixenobiotic resistance (MXR)-associated proteins. Overall, these findings, associated with bioinformatic analysis, highlight the potential of the PAH mixture to modulate the estrogen pathway and induce oxidative stress in O. niloticus hepatocytes. Understanding the mechanisms underlying these effects is crucial for assessing the ecological risks of PAH exposure and developing appropriate strategies to mitigate their adverse impacts on aquatic organisms.

Glyphosate and aminomethylphosphonic acid metabolite (AMPA) modulate the phenotype of murine melanoma B16-F1 cells.

Pesticides are contaminants run-offs from agricultural areas with a global concern due to their toxicity for non-target organisms. The Brazilian Health Surveillance Agency reported about 63% of the food contain pesticide residues. Glyphosate is a herbicide used worldwide but its toxicity is not a consensus among specialists around the world. AMPA (aminomethylphosphonic acid) is a glyphosate metabolite that can be more toxic than the parental molecule. Melanoma murine B16-F1 cells were exposed to glyphosate and AMPA to investigate the cell profile and possible induction to a more malignant phenotype. Glyphosate modulated the multi-drug resistance mechanisms by ABCB5 gene expression, decreasing cell attachment, increasing cell migration and inducing extracellular vesicles production, and the cells exposed to AMPA revealed potential damages to DNA. The present study observed that AMPA exhibits high cytotoxicity, which suggests a potential impact on non-tumor cells, which are, in general, more susceptible to chemical exposure. Conversely, glyphosate favored a more metastatic and chemoresistant behavior in cancer cells, highlighting the importance of additional research in this area.

Complex mixtures of pesticides and metabolites modulate the malignant phenotype of murine melanoma B16-F1 cells.

Pesticides use increased worldwide with a record in Brazil. Although several works addressed the effects of pesticides on living organisms, only a few considered their mixture, and even fewer tried to unravel their role in tumoral progression. Due to the relevance of cancer, in the present study, the effects of the mixture of pesticides widely used in Brazil (Glyphosate, 2,4-dichlorophenoxyacetic acid, Mancozeb, Atrazine, Acephate, and Paraquat) and their main metabolites (Aminomethylphosphonic Acid, 2,4-diclorophenol, Ethylenethiourea, Desethylatrazine, Methamidophos, and Paraquat) were investigated on the malignancy phenotype of murine melanoma B16-F1 cells after acute (24 h) and chronic (15 days) exposures. The tested concentrations were based on the Acceptable Daily Intake (ADI) value established by Brazilian legislation. The set of results showed that these chemicals modulate important parameters of tumor progression, affecting the expression of genes related to tumor aggressiveness (Mmp14 and Cd44) and multidrug resistance (Abcb1, Abcc1, and Abcc4), as well as tissue inhibitors of metalloproteinases (Timp1, Timp2, and Timp3). These findings revealed an absence of cytotoxicity but showed modulation of migration, invasion, and colonization capacity of B16-F1 cells. Together, the results point to some negative ways that exposure to pesticides can affect the progression of melanoma and raise a concern related to the increasing trend in pesticide use in Brazil, as the country is one of the major world food suppliers.

Cytotoxicity of bismuth nanoparticles in the murine macrophage cell line RAW 264.7.

A promising use of bismuth nanoparticles (BiNPs) for different biomedical applications leads to a search for the elucidation of their toxicity mechanisms, since toxicity studies are still at early stage. In the current study, cytotoxic effects of BiNPs produced by laser ablation in solution (LASiS) was investigated in the murine macrophage line RAW 264.7. The cells were exposed to 0.01-50 µg ml-1 of BiNPs for 24 and 48 h and then cytotoxicity assays were performed. Decrease of MTT conversion to formazan and of cell attachment were observed with no effects on cell proliferation. No loss of membrane integrity or significant changes of ROS and RNS levels were observed in exposed cells. Foremost, increased phagocytic activity and DNA repair foci occurred for cells exposed to BiNPs. These effects are important findings that must be considered in the case of biomedical application of BiNPs, since inappropriate macrophages activation and inactivation may lead to immunotoxicity. Bismuth nanoparticles (BiNPs) produced by laser ablation in solution and stabilized with BSA decrease enzyme-dependent MTT conversion to formazan and increase phagocytic activity and DNA repair foci in murine macrophage line RAW 264.7 when exposed to 50 µg ml-1. These effects are findings that should be considered in the case of biomedical application of BiNPs, since inappropriate macrophages activation and inactivation may lead to immunotoxicity.

Malignancy and tumorigenicity of melanoma B16 cells are not affected by silver and gold nanoparticles.

Gold (AuNP) and silver (AgNP) nanoparticles have been incorporated into many therapeutic and diagnostic applications. However, previous studies revealed toxic properties as well as the hormesis phenomenon of many nanoparticles in different biological models. To evaluate the effects of low concentrations of AuNP and AgNP on murine melanoma cells B16F1 and B16F10 and relate them with phenotype changes, cells were exposed for 24 and 48 h. No cytotoxicity was observed for B16 cells through neutral red, MTT, trypan blue, and crystal violet assays at concentrations from 0.01 to 10 ng mL-1. Likewise, the nanoparticles did not interfere with drug-efflux activity, cell migration, cell cycle, and colony formation. Slight toxicity was observed for B16F10 exposed to 100 ng mL-1, with a decreased number of viable and attached cells, indicating differential sensitivity of B16F1 and B16F10 cells to the nanoparticles. Furthermore, colony size dispersion decreased for both B16 cell sub-lines. Therefore, there is no evidence that the tested concentrations of AuNP and AgNP can render B16 cells more aggressive and malignant, which is important since both nanoparticles are already largely used in nanotechnological products. Considering studies that have showed the hormesis effect of nanoparticles at low concentrations, which could protect cancer cells against chemotherapy, further investigation is advised.