Effects of Phthalate Esters (PAEs) on Cell Viability and Nrf2 of HepG2 and 3D-QSAR Studies

In Vitro Cytotoxic Potential and Integrated Network Pharmacology, Molecular Docking and Molecular Dynamic Approaches to Decipher the Mechanism of Gymnostachyum febrifugum Benth., in the Treatment of Breast Cancer

Gymnostachyum febrifugum, a less-known ethnomedicinal plant from the Western Ghats of India, is used to treat various diseases and serves as an antioxidant and antibacterial herb. The present study aims to profile the cytotoxic phytochemicals in G. febrifugum roots using GC-MS/MS, in vitro confirmation of cytotoxic potential against breast cancer and an in silico study to understand the mechanism of action. Phytochemical profiling using GC-MS/MS showed the presence of eight cytotoxic molecules with lupeol in high abundance. A potent cytotoxic effect of G. febrifugum roots against breast cancer was also observed with antiproliferation, antimigration, inhibition in colony formation and death of breast cancer cells. Further, the cytotoxic potential of the plant was confirmed with the apoptosis of cells as observed in the flow cytometry. In silico network pharmacology, GO and KEGG analysis suggested the modulation of proteins of MAPK, PI3K-AKT and apoptosis pathways by lupeol to induce cytotoxicity in breast cancer. Further, dynamic simulation revealed MAPK and AKT as the major targets for lupeol. Our studies comprehensively elucidated the role of lupeol, a major phytochemical in G. febrifugum to induce cytotoxicity against breast cancer by targeting major cancer signaling pathways, providing a promising strategy and scientific basis to explore lupeol in targeted cancer therapy.

Diisooctyl phthalate (DIOP) exposure leads to cell apoptosis to HUVEC cells and toxicity to Caenorhabditis elegans through increasing the oxidative stress

Diisooctyl phthalate (DIOP), a common phthalate plasticizer, is frequently encountered in everyday life. Despite its widespread use, there is a dearth of toxicological research on DIOP, resulting in incomplete knowledge of its potential harmful effects. Our current research endeavored to provide a comprehensive evaluation of DIOP's toxicological profile using both cellular and Caenorhabditis elegans models as our in vitro and in vivo study subjects. Our results demonstrate that DIOP markedly decreases the viability and colony-forming ability of HUVECs. Moreover, this cytotoxicity correlates with elevated levels of reactive oxygen species (ROS), causing cell cycle arrest at the G1 phase and the induction of cell apoptosis. In addition, DIOP adversely affects the growth, movement, and reproductive fitness of C. elegans, as well as other physiological aspects such as body curvature, egg-laying capability, and body length. C. elegans exposed to DIOP exhibit increased oxidative stress, evidenced by higher ROS levels and lipofuscin buildup. Importantly, the PI3K/AKT and MAPK pathways are implicated in the response to DIOP-induced toxicity. This study, therefore, highlights the potential toxicity of DIOP in both cellular and organismal models, advancing our understanding of the detrimental effects associated with exposure to DIOP.

Diethyl phthalate and dibutyl phthalate disrupt sirtuins expression in the HepG2 cells

Background

Phthalates are additives used as plasticizers among other uses, classified as endocrine disruptors and may contribute to some metabolic disorders. The aim of this work was to determine the effect of the exposure of diethyl phthalate (DEP) and dibutyl phthalate (DBP) on cell viability and reactive oxygen species (ROS) production, as well as the regulation of sirloins in HepG2 cells.

Methods

HepG2 cells were exposed to DEP or DBP at 0.1, 1, 10 and 100 μg/mL, and after 48 or 72 h the gene and protein expression of sirtuins was quantified by qRT-PCR and Western-Blot, respectively.

Results

Results showed that even at a low concentration of 0.1 μg/mL DEP affected the expression of Sirt3 and Sirt4, whereas DBP at 0.1 μg/mL affected Sirt3 and Sirt5 gene expression. Protein analysis showed a reduction in Sirt1 levels at a DEP concentration of 1 μg/mL and higher, while DBP at higher dose (100 μg/mL) decreased Sirt3 protein levels. Cell viability decreased by 20% only at higher dose (100 μg/mL) and ROS production increased at 10 and 100 μg/mL for both phthalates.

Conclusion

These findings indicate that exposure to low concentrations (0.1 μg/mL) of DEP or DBP can negatively influence the expression of some sirtuins.

Long-term di-(2-ethylhexyl) phthalate exposure reduces sorafenib treatment efficacy by enhancing mesenchymal transition in hepatocellular carcinoma

Di(2-ethylhexyl) phthalate (DEHP) is a worldwide common plasticizer. Nevertheless, DEHP is easily leached out to the environment due to the lack of covalent bonds with plastic. High dose of DEHP exposure is often observed in hemodialysis patients because of the continual usage of plastic medical devices. Although the liver is the major organ that catabolizes DEHP, the impact of long-term DEHP exposure on the sensitivity of liver cancer to chemotherapy remains unclear. In this study, we established long-term DEHP-exposed hepatocellular carcinoma (HCC) cells and two NOD/SCID mice models to investigate the effects and the underlying mechanisms of long-term DEHP exposure on chemosensitivity of HCC. The results showed long-term DEHP exposure potentially increased epithelial-mesenchymal transition (EMT) in HCC cells. Next generation sequencing showed that long-term DEHP exposure increased cell adhesion/migratory related genes expression and blunted sorafenib treatment induced genes alterations. Long-term exposure to DEHP reduced the sensitivity of HCC cells to sorafenib-induced anti-migratory effect by enhancing the EMT transcription factors (slug, twist, and ZEB1) and mesenchymal protein (vimentin) expression. In NOD/SCID mice model, we showed that long-term DEHP-exposed HCC cells exhibited higher growth rate. Regarding the anti-HCC effects of sorafenib, subcutaneous HuH7 tumor grew slowly in sorafenib-treated mice. Nonetheless, the anti-tumor growth effect of sorafenib was not observed in long-term DEHP-exposed mice. Higher mesenchymal markers and proliferating cell nuclear antigen (PCNA) expression were found in sorafenib-treated long-term DEHP-exposed mice. In conclusion, long-term DEHP exposure promoted migratory activity in HCC cells and decreased sorafenib sensitivity in tumor-bearing mice.

Toxicity Rank Order (TRO) As a New Approach for Toxicity Prediction by QSAR Models

Quantitative Structure-Activity Relationship (QSAR) models are commonly used for risk assessment of emerging contaminants. The objective of this study was to use a toxicity rank order (TRO) as an integrating parameter to improve the toxicity prediction by QSAR models. TRO for each contaminant was calculated from collected toxicity data including acute toxicity concentration and no observed effect concentration. TRO values associated with toxicity mechanisms were used to classify pollutants into three modes of action consisting of narcosis, transition and reactivity. The selection principle of parameters for QSAR models was established and verified. It showed a reasonable prediction of toxicities caused by organophosphates and benzene derivatives, especially. Compared with traditional procedures, incorporating TRO showed an improved correlation coefficient of QSAR models by approximately 10%. Our study indicated that the proposed procedure can be used for screening modeling parameter data and improve the toxicity prediction by QSAR models, and this could facilitate prediction and evaluation of environmental contaminant toxicity.

Molecular Design and Mechanism Analysis of Phthalic Acid Ester Substitutes: Improved Biodegradability in Processes of Sewage Treatment and Soil Remediation

Phthalic acid esters (PAEs) have the characteristics of environmental persistence. Therefore, improving the biodegradability of PAEs is the key to reducing the extent of ecological harm realized. Firstly, the scoring function values of PAEs docking with various degrading enzymes in sewage treatment were calculated. Based on this, a 3D-quantitative structure-activity relationship (3D-QSAR) model for PAE biodegradability was built, and 38 PAE substitutes were created. By predicting the endocrine-disrupting toxicity and functions of PAE substitutes, two types of PAE substitutes that are easily degraded by microorganisms, have low toxicity, and remain functional were successfully screened. Meanwhile, the differences in the mechanism of molecular degradation difference before and after PAE modification were analyzed based on the distribution characteristics of amino acid residues in the molecular docking complex. Finally, the photodegradability and microbial degradability of the PAE substitutes in the soil environment was evaluated. From the 3D-QSAR model design perspective, the modification mechanism of PAE substitutes suitable for sewage treatment and soil environment degradation was analyzed. We aim to improve the biodegradability of PAEs at the source and provide theoretical support for alleviating the environmental hazards of using PAEs.

Groundwater contamination pathways of phthalates and bisphenol A: origin, characteristics, transport, and fate - A review

Phthalic acid esters (PAEs) or phthalates and bisphenol A (BPA) are emerging organic contaminants (EOCs) that may harm biota and human health. Humans can be exposed to these contaminants by drinking water consumption from water sources such as groundwater. Before their presence in aquifer systems, phthalates and BPA can be found in many matrices due to anthropogenic activities, which result in long-term transport to groundwater reservoirs by different mechanisms and reaction processes. The worldwide occurrence of phthalates and BPA concentrations in groundwater have ranged from 0.1 × 10^-3 to 3 203.33 µg L^-1 and from 0.09 × 10^-3 to 228.04 µg L^-1, respectively. Therefore, the aim of this review is to describe the groundwater contamination pathways of phthalates and BPA from the main environmental sources to groundwater. Overall, this article provides an overview that integrates phthalate and BPA environmental cycling, from their origin to human reception via groundwater consumption. Additionally, in this review, the readers can use the information provided as a principal basis for existing policy ratification and for governments to develop legislation that may incorporate these endocrine disrupting compounds (EDCs) as priority contaminants. Indeed, this may trigger the enactment of regulatory guidelines and public policies that help to reduce the exposure of these EDCs in humans by drinking water consumption.

Effects of DEHP, DEHT and DINP Alone or in a Mixture on Cell Viability and Mitochondrial Metabolism of Endothelial Cells In Vitro

Plasticizers are chemicals in high demand, used in a wide range of commercial products. Human are exposed through multiple pathways, from numerous sources, to multiple plasticizers. This is a matter of concern, as it may contribute to adverse health effects. The vascular system carries plasticizers throughout the body and therefore can interact with the endothelium. The aim of the study was to evaluate the in vitro toxicity on endothelial cells by considering the individual and the mixture effects of bis-(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP) or bis-(2-ethylhexyl) terephthalate (DEHT). In this study, their cytotoxicity on HMEC-1 cells was evaluated on cell function (viability, cell counting, total glutathione and intracellular adenosines) and mitochondrial function (mitochondrial respiration). Results showed cellular physiological perturbations induced with all the condition tested, excepted for DEHT. Plasticizers induced a cytotoxicity by targeting mitochondrial respiration, depleting mitochondrial ATP production and increasing glycolytic metabolism. Additionally, delayed effects were observed between the cellular and the mitochondrial parameters. These results suggest that endothelial cells could go through a metabolic adaptation to face plasticizer-induced cellular stress, to effectively maintain their cellular processes. This study provides additional information on the adverse effects of plasticizers on endothelial cells.