Effect of the environmental pollutant bisphenol A dimethacylate (BAD) on Ca2+ movement and viability in OC2 human oral cancer cells

Impact of bisphenol A and analogues eluted from resin-based dental materials on cellular and molecular processes: An insight on underlying toxicity mechanisms

Dental resin systems, used for artificial replacement of teeth and their surrounding structures, have gained popularity due to the Food and Drug Administration's (FDA) recommendation to reduce dental amalgam use in high-risk populations and medical circumstances. Bisphenol A (BPA), an endocrine-disrupting chemical, is an essential monomer within dental resin in the form of various analogues and derivatives. Leaching of monomers from resins results in toxicity, affecting hormone metabolism and causing long-term health risks. Understanding cellular-level toxicity profiles of bisphenol derivatives is crucial for conducting toxicity studies in in vivo models. This review provides insights into the unique expression patterns of BPA and its analogues among different cell types and their underlying toxicity mechanisms. Lack of a consistent cell line for toxic effects necessitates exploring various cell lines. Among the individual monomers, BisGMA was found to be the most toxic; however, BisDMA and BADGE generates BPA endogenously and found to elicit severe adverse reactions. In correlating in vitro data with in vivo findings, further research is necessary to classify the elutes as human carcinogens or xenoestrogens. Though the basic mechanisms underlying toxicity were believed to be the production of intracellular reactive oxygen species and a corresponding decline in glutathione levels, several underlying mechanisms were identified to stimulate cellular responses at low concentrations. The review calls for further research to assess the synergistic interactions of co-monomers and other components in dental resins. The review emphasizes the clinical relevance of these findings, highlighting the necessity for safer dental materials and underscoring the potential health risks associated with current dental resin systems.

Non-monotonic effects of Bisphenol A Dimethacrylate on male mouse reproductive system and fertility leads to impaired conceptive performance

As an estrogenic agent, Bisphenol A Dimethacrylate (Bis-DMA) may incite alterations in both the reproductive tract and the neuroendocrine axis, and thus have the potential to affect the proper development, maturity and conceptive performance in animals. We investigated the consequences of 14 weeks of exposure to different concentrations of Bis-DMA on male mouse conceptive performance. Male mice were exposed to Bis-DMA (0, 0.1 mg/L, 1.0 mg/L or 10 mg/L) via drinking water, and the effects on fertility, reproductive organ weights, reproductive hormone levels, sperm counts and testicular histology were assessed. We clearly demonstrate that prolonged exposure of male mice to Bis-DMA negatively affects fertility and reproduction causing significant reductions in sperm counts, non-monotonic effects on serum LH and testosterone levels, increased seminal vesicle weights, lower number of embryonic implantations and viable fetuses, as well as, increased embryonal resorptions in females mated by Bis-DMA treated males. Furthermore, Bis-DMA caused abnormalities in testicular infrastructure with atrophic seminiferous tubules exhibiting intraepithelial vacuolization and disorganization, loss and shedding of germ cells into the lumen, and presence of apoptotic cells. Our data collectively suggest that Bis-DMA adversely affects male fertility and reproduction by interference with normal hormone signaling in the testis, inducing changes in testicular infrastructure and ultimately leading to impaired reproductive function and fertility.

Fenvalerate induces oxidative hepatic lesions through an overload of intracellular calcium triggered by the ERK/IKK/NF-κB pathway

Fenvalerate (FEN), a mainstream pyrethroid pesticide, was initially recommended as a low-toxicity agent for controlling agricultural and domestic pests. Despite the widespread use of FEN worldwide, little data are available on FEN-induced hepatic lesions and molecular mechanisms. In the present study, we first performed an occupational cross-sectional study on FEN factory workers and found that the levels of serum alanine aminotransferase (ALT) and total antioxidant capacity increased, whereas malondialdehyde decreased in laborers in the working areas where the levels of airborne FEN were much higher compared with the office area. The results were then confirmed by animal experiments that abnormal hepatic histology, increased ALT level, and compromised hepatic oxidative capability were observed in rats exposed to a high concentration of FEN. Furthermore, the bioinformatics analysis of gene microarray in rat liver tissue showed that FEN significantly changed the expressions of genes related to the regulation of intracellular calcium ion homeostasis and the calcium signal pathway. Finally, the functional experiments in Buffalo rat liver (BRL) cells demonstrated that FEN first activated ERK MAPK, followed by IKK and NF-κB, which triggered the transcription of genes responsible for accelerating an overload of intracellular calcium ions, prompted reactive oxygen species generation in the mitochondria, and finally, induced hepatic cellular apoptosis. The calcium signaling pathway and in particular, an overload of intracellular calcium play a critical role in this pathophysiological process via the ERK/IKK/NF-κB pathway. Our study furthers the understanding of the mechanism of FEN-induced hepatic injuries and may have implications in the prevention and control of liver diseases induced by environmental pesticides.-Qiu, L.-L., Wang, C., Yao, S., Li, N., Hu, Y., Yu, Y., Xia, R., Zhu, J., Ji, M., Zhang, Z., Wang S.-L. Fenvalerate induces oxidative hepatic lesions through an overload of intracellular calcium triggered by the ERK/IKK/NF-κB pathway.

Mechanisms of resveratrol-induced changes in cytosolic free calcium ion concentrations and cell viability in OC2 human oral cancer cells

Resveratrol is a natural compound that affects cellular calcium (Ca(2+)) homeostasis and viability in different cells. This study examined the effect of resveratrol on cytosolic free Ca(2+) concentrations ([Ca(2+)]i) and viability in OC2 human oral cancer cells. The Ca(2+)-sensitive fluorescent dye fura-2 was used to measure [Ca(2+)]i, and water-soluble tetrazolium-1 was used to measure viability. Resveratrol evoked concentration-dependent increase in [Ca(2+)]i. The response was reduced by removing extracellular Ca(2+). Resveratrol also caused manganese-induced fura-2 fluorescence quench. Resveratrol-evoked Ca(2+) entry was inhibited by nifedipine and the protein kinase C (PKC) inhibitor GF109203X but was not altered by econazole, SKF96365, and the PKC activator phorbol 12-myristate 13 acetate. In Ca(2+)-free medium, treatment with the endoplasmic reticulum Ca(2+) pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) abolished resveratrol-evoked [Ca(2+)]i rise. Conversely, treatment with resveratrol inhibited BHQ-evoked [Ca(2+)]i rise. Inhibition of phospholipase C (PLC) with U73122 abolished resveratrol-evoked [Ca(2+)]i rise. At 20-100 μM, resveratrol decreased cell viability, which was not affected by chelating cytosolic Ca(2+)with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester. Annexin V-fluorescein isothiocyanate staining data suggest that resveratrol at 20-40 μM induced apoptosis in a concentration-dependent manner. Collectively, in OC2 cells, resveratrol induced [Ca(2+)]i rise by evoking PLC-dependent Ca(2+) release from the endoplasmic reticulum and by causing Ca(2+) entry via nifedipine-sensitive, PKC-regulated mechanisms. Resveratrol also caused Ca(2+)-independent apoptosis.