Foxo1 Attenuates NaF-Induced Apoptosis of LS8 Cells through the JNK and Mitochondrial Pathways

Targeting JNK kinase inhibitors via molecular docking: A promising strategy to address tumorigenesis and drug resistance

Among members of the mitogen-activated protein kinase (MAPK) family, c-Jun N-terminal kinases (JNKs) are vital for cellular responses to stress, inflammation, and apoptosis. Recent advances have highlighted their important implications in cancer biology, where dysregulated JNK signalling plays a role in the growth, progression, and metastasis of tumors. The present understanding of JNK kinase and its function in the etiology of cancer is summarized in this review. By modifying a number of downstream targets, such as transcription factors, apoptotic regulators, and cell cycle proteins, JNKs exert diverse effects on cancer cells. Apoptosis avoidance, cell survival, and proliferation are all promoted by abnormal JNK activation in many types of cancer, which leads to tumor growth and resistance to treatment. JNKs also affect the tumour microenvironment by controlling the generation of inflammatory cytokines, angiogenesis, and immune cell activity. However, challenges remain in deciphering the context-specific roles of JNK isoforms and their intricate crosstalk with other signalling pathways within the complex tumor environment. Further research is warranted to delineate the precise mechanisms underlying JNK-mediated tumorigenesis and to develop tailored therapeutic strategies targeting JNK signalling to improve cancer management. The review emphasizes the role of JNK kinases in cancer biology, as well as their potential as pharmaceutical targets for precision oncology therapy and cancer resistance. Also, this review summarizes all the available promising JNK inhibitors that are suggested to promote the responsiveness of cancer cells to cancer treatment.

Epigallocatechin-3-gallate attenuates fluoride induced apoptosis via PI3K/FoxO1 pathway in ameloblast-like cells

Fluoride is a double-edged sword. It was widely used for early caries prevention while excessive intake caused a toxicology effect, affected enamel development, and resulted in dental fluorosis. The study aimed to evaluate the protective effect and mechanism of Epigallocatechin-3-gallate (EGCG) on the apoptosis induced by fluoride in ameloblast-like cells. We observed that NaF triggered apoptotic alterations in cell morphology, excessive NaF arrested cell cycle at the G1, and induced apoptosis by up-regulating Bax and down-regulating Bcl-2. NaF activated the insulin-like growth factor receptor (IGFR), and phosphatidylinositol-3-hydroxylase (p-PI3K), while dose-dependently down-regulating the expression of Forkhead box O1 (FoxO1). EGCG supplements reversed the changes in LS8 morphology, the cell cycle, and apoptosis induced by fluoride. These results indicated that EGCG possesses a protective effect against fluoride toxicity. Furthermore, EGCG suppressed the activation of p-PI3K and the down-regulation of FoxO1 caused by fluoride. Collectively, our findings suggested that EGCG attenuated fluoride-induced apoptosis by inhibiting the PI3K/FoxO1 signaling pathway. EGCG may serve as a new alternative method for dental fluorosis prevention, control, and treatment.

MiR-1a-3p Inhibits Apoptosis in Fluoride-exposed LS8 Cells by Targeting Map3k1

Dental fluorosis is a common chemical disease. It is currently unclear how fluorosis occurs at the molecular level. We used miRNA-seq to look at the differences between miRNAs in the cell line of ameloblasts LS8 that had been treated with 3.2 mmol/L NaF. We also performed gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. miR-1a-3p levels were significantly lower in mouse LS8 cells treated with 3.2 mmol/L NaF, and miR-1a-3p-targeted genes were significantly enriched in the MAPK pathway. LS8 cells were divided into four groups: control, NaF, NaF+miR-1a-3p mimics, and NaF+miR-1a-3p mimics normal control groups. Cellular morphology was observed by an inverted microscope, and the proliferation activity of LS8 cells was assessed by Cell Counting Kit-8 (CCK-8). Using the real-time quantitative polymerase chain reaction (RT-qPCR), transcription levels of miR-1a-3p and Map3k1 were detected. The expressions of Bax, Bcl-2, Map3k1, p38MAPK, ERK1/2, p-p38MAPK, and p-ERK1/2 were measured by Western blot. After bioinformatics analysis, we used a luciferase reporter assay (LRA) to validate the target of miR-1a-3p, showing that miR-1a-3p could inhibit apoptosis while increasing proliferation in fluoride-exposed LS8 cells. Generally, miR-1a-3p might directly inhibit Map3k1, reduce MAPK signal pathway activation, and promote phosphorylation. Thus, our findings revealed that the interaction of miR-1a-3p with its target gene Map3k1 and MAPK signal pathway might decrease the apoptosis of LS8 cells treated with 3.2 mmol/L NaF.

ERS Mediated by GRP-78/PERK/CHOP Signaling Is Involved in Fluoride-Induced Ameloblast Apoptosis

Fluoride can be widely ingested from the environment, and its excessive intake could result in adverse effects. Dental fluorosis is an early sign of fluoride toxicity which can cause esthetic and functional problems. Though apoptosis in ameloblasts is one of the potential mechanisms, the specific signal cascade is in-conclusive. High-throughput sequencing and molecular biological techniques were used in this study to explore the underlying pathogenesis of dental fluorosis, for its prevention and treatment. A fluorosis cell model was established. Viability and apoptosis rate of mouse ameloblast-derived cell line (LS8 cells) was measured using cell counting kit-8 (CCK-8) assay and flow cytometry analysis. Cells were harvested with or without 2-mM sodium fluoride (NaF) stimulation for high-throughput sequencing. Based on the sequencing data, subcellular structures, endoplasmic reticulum stress (ERS), and apoptosis related biomarkers were verified using transmission electron microscopy, quantitative real-time polymerase chain reaction, and Western blotting techniques. Expression of ERS markers, apoptosis related proteins, and enamel formation enzymes were detected using Western blotting after addition of 4-phenylbutyrate (4-PBA). NaF-inhibited LS8 cells displayed time- and dose- dependent viability. Additionally, apoptosis and morphological changes were observed. RNA-sequencing data showed that protein processing in endoplasmic reticulum was obviously affected. ERS and apoptosis were induced by excessive NaF. Downregulation of kallikrein-related peptidase 4 (KLK4) was also observed. Inhibition of ERS by 4-PBA rescued the apoptotic and functional protein changes in cells. Excessive fluoride induces apoptosis by activating ERS, which is mediated by GRP-78/PERK/CHOP signaling. Key proteinase is present in maturation-stage enamel; KLK4 was also affected by fluoride, but rescued by 4-PBA. This study presents a possibility for therapeutic strategies for dental fluorosis, while further exploration is required.

Inhibition of autophagy reduces the rate of fluoride-induced LS8 apoptosis via regulating ATG5 and ATG7

Excessive fluoride affects ameloblast differentiation and tooth development. The fate of fluorinated ameloblasts is determined by multiple signaling pathways in response to a range of stimuli. Both autophagy and apoptosis are involved in the regulation of dental fluorosis as well as in protein synthesis and enamel mineralization. Emerging evidence suggests that autophagy and apoptosis are interconnected and that their interaction greatly influences cell death. However, the effect of autophagy on apoptosis in fluoride-treated ameloblasts is unclear. Here, we employed an in vitro cellular model of fluorosis in mouse ameloblast-like LS8 cells and induced autophagy using sodium fluoride (NaF). Our findings suggest that NaF treatment induces autophagy in LS8 cells, and ATG5 and ATG7 are important molecules involved in this process. We also showed that NaF treatment reduced cell viability in Atg5/7 siRNA and autophagy inhibitor-treated LS8 cells. More importantly, NaF-induced apoptosis can be reversed by inhibiting early stage of autophagy. In conclusion, our study shows that autophagy is closely related to dental fluorosis, and inhibition of autophagy, especially ATG5/7, reduces fluoride-induced cell death and apoptosis.

Role of the JNK Pathway in Bladder Cancer

Bladder cancer, one of the most frequently diagnosed cancers worldwide, is associated with high morbidity and mortality and a poor prognosis. The bladder cancer types include 1) non-muscle invasive bladder cancer (NMIBC) and 2) muscle invasive bladder cancer (MIBC). Metastases and chemoresistance in MIBC patients are the leading causes of the high death rate. c-Jun N-terminal kinase (JNK) is an important factor for the undifferentiated state of cancer cells. JNK belongs to the mitogen-activated protein kinases (MAPKs) family; it is activated by various extracellular stimuli, such as stress, radiation, and growth factors and mediates diverse cellular functions, such as apoptosis, autophagy, proliferation, invasion, and migration by mediating AKT (Ak strain transforming), ATG (Autophagy related), mTOR (Mammalian target of rapamycin), and caspases 3, 8, and 9. This review describes the JNK-related functions, mechanisms, and signaling in bladder cancer.

Effects of fluoride exposure on mitochondrial function: Energy metabolism, dynamics, biogenesis and mitophagy

Fluoride is ubiquitous in the environment. Furthermore, drinking water represents the main source of exposure to fluoride for humans. Interestingly, low fluoride concentrations have beneficial effects on bone and teeth development; however, chronic fluoride exposure has harmful effects on human health. Besides, preclinical studies associate fluoride toxicity with oxidative stress, inflammation, and apoptosis. On the other hand, it is well-known that mitochondria play a key role in reactive oxygen species production. By contrast, fluoride's effect on processes such as mitochondrial dynamics, biogenesis and mitophagy are little known. These processes modulate the size, content, and distribution of mitochondria and their depuration help to counter the reactive oxygen species production and cytochrome c release, thereby allowing cell survival. However, a maladaptive response could enhance fluoride-induced toxicity. The present review gives a brief account of fluoride-induced mitochondrial alterations on soft and hard tissues, including liver, reproductive organs, heart, brain, lung, kidney, bone, and tooth.

Advances in indole-containing alkaloids as potential anticancer agents by regulating autophagy

Cancer is a leading cause of death worldwide, and cancer development is often associated with disturbances in the autophagy process. Autophagy is a catabolic process involved in many physiological processes, crucial for cell growth and survival. It is an intracellular lysosomal/vacuolar degradation system. In this system, inner cytoplasmic cell membrane is degraded by lysosomal hydrolases, and the products are released back into the cytoplasm. Indole alkaloids are natural products extensively found in nature and have been proven to possess various pharmacological activities. In recent years, pharmacological studies have demonstrated another potential of indole alkaloids, autophagy regulation. The regulation may contribute to the efficacy of indole alkaloids in preventing and treating cancer. This review summarizes the current understanding of indole alkaloids' effect on tumor cells and autophagy. Then, we focus on mechanisms by which indole alkaloids can target the autophagy process associated with cancer, including the PI3K/Akt/mTOR signaling pathway, MAPK signaling pathway, ROS signaling pathway, Beclin-1, and so on. Literature has been surveyed primarily from 2009 to Nov. 2021, and some semisynthetic or fully synthetic indole derivatives are also discussed.

Study on the protective effects of danshen-honghua herb pair (DHHP) on myocardial ischaemia/reperfusion injury (MIRI) and potential mechanisms based on apoptosis and mitochondria

CONTEXT

Danshen, the dried root and rhizome of Salvia miltiorrhiza Bunge (Labiatae) and honghua, the dried flower of Carthamus tinctorius L. (Compositae) as the herb pair was used to treat cardiovascular diseases (CVD).

OBJECTIVE

To study the effects of DHHP on MIRI and mechanisms based on apoptosis and mitochondria.

MATERIALS AND METHODS

36 SD rats (n = 6) were randomly divided into control group (Con), the ischaemia-reperfusion group (IR), positive control (Xinning tablets, XNT, 1 g/kg/d) and DHHP (1.2, 2.4, and 4.8 g/kg/d). Except for Con, the other groups were intragastrically administrated for 5 d, the rat hearts were isolated to establish the MIRI model in vitro for evaluating the effects of DHHP on MIRI. 24 SD rats (n = 6) were randomly divided into Con, IR, DPPH2.4 (2.4 g/kg/d) and DPPH 2.4 + Atractyloside (ATR) (2.4 + 5 mg/kg/d), administered intragastrically for 5 d, then treated with ATR (5 mg/kg/d) by intraperitoneal injection in DPPH2.4 + ATR group, took rat hearts to establish MIRI model in vitro for revealing mechanism.

RESULTS

Myocardial infarct sizes were, respectively, 0.35%, 40.09%, 15.84%, 30.13%, concentrations of NAD⁺ (nmol/gw/w) were 144, 83, 119, and 88, respectively, in Con, IR, DHHP2.4, DHHP2.4 + ATR group. Cleaved caspase-3 were 0.3, 1.6, 0.5 and 1.3% and cleaved caspase-9 were 0.2, 1.1, 0.4 and 0.8%, respectively, in Con, IR, DHHP2.4 and DHHP2.4 + ATR group. The beneficial effects of DHHP on MIRI were reversed by ATR.

CONCLUSIONS

The improvement of MIRI by DHHP may be involved in inhibiting MPTP opening, decreasing oxidative damage, alleviating ischaemic injury and inhibiting cardiomyocyte apoptosis.

NaF reduces KLK4 expression by decreasing Foxo1/Runx2 expression in LS8 cells

OBJECTIVE

This study aimed to investigate the effect of high fluoride on runt-related transcription factor 2 (Runx2) expression and to explore the possible relationship among Runx2, forkhead box o1 (Foxo1) and kallikrein 4 (KLK4) in high fluoride-treated ameloblasts.

DESIGN

Ameloblast-like cells (LS8 cells) were exposed to various concentrations of sodium fluoride (NaF) for up to 48 h. Runx2 expression was downregulated by gene silencing, and Foxo1 expression was up- and downregulated by gene overexpression and silencing, respectively. The mRNA and protein levels of Runx2, Foxo1, KLK4 and matrix metalloproteinase 20 (MMP20) were detected by qRT-PCR and western blotting.

RESULTS

Runx2 expression was decreased in a dose- and time-dependent manner in NaF-treated LS8 cells. The knockdown of Runx2 markedly decreased KLK4 expression in LS8 cells under NaF conditions. However, the variation trend of MMP20 was unclear. In addition, forced Foxo1 expression led to significant upregulation of Runx2 in LS8 cells under NaF conditions. In contrast, the knockdown of Foxo1 markedly decreased the Runx2 protein levels under NaF conditions. Moreover, Foxo1 downregulation markedly decreased runx2 mRNA levels, and this inhibition in LS8 cells was intensified when combined with NaF treatment.

CONCLUSION

The results indicated that NaF reduces Runx2 expression in LS8 cells and that decreased Foxo1/Runx2 expression induced by high fluoride is a cause of low KLK4 expression.

Recent advances in cellular effects of fluoride: an update on its signalling pathway and targeted therapeutic approaches

Fluoride is a natural element essential in minute quantities in human's to maintain dental and skeletal health. However, the disease fluorosis manifests itself due to excessive fluoride intake mostly through drinking water and sometimes through food. At the cellular energetics level, fluoride is a known inhibitor of glycolysis. At the tissue level, the effect of fluoride has been more pronounced in the musculoskeletal systems due to its ability to retain fluoride. Fluoride alters dentinogenesis, thereby affecting the tooth enamel formation. In bones, fluoride alters the osteogenesis by replacing calcium, thus resulting in bone deformities. In skeletal muscles, high concentration and long term exposure to fluoride causes loss of muscle proteins leading to atrophy. Although fluorosis is quite a familiar problem, the exact molecular pathway is not yet clear. Extensive research on the effects of fluoride on various organs and its toxicity was reported. Indeed, it is clear that high and chronic exposure to fluoride causes cellular apoptosis. Accordingly, in this review, we have highlighted fluoride-mediated apoptosis via two vital pathways, mitochondrial-mediated and endoplasmic reticulum stress pathways. This review also elaborates on new cellular energetic, apoptotic pathways and therapeutic strategies targeted to treat fluorosis.

JNK Signaling Pathway Mediates Fluoride-Induced Upregulation of CK1α during Enamel Formation

Fluorosis is a defect in the enamel mineral content caused by excessive fluoride intake during amelogenesis; the interaction of various factors in the development and progression of fluorosis has not been defined. Casein kinase 1α (CK1α) is constitutively active in cells and is involved in diverse cellular processes; however, its expression in fluorosis has not been measured. This study aimed to investigate the effects of fluoride on CK1α expression and to assess the regulation of molecular signaling involving fluoride and CK1α during enamel development. Kunming mice were randomly divided into the control and F groups with induced clinical features of fluorosis. The F group mice, including mothers and newborns, were treated with 50 ppm fluoridated water. Immunohistochemical staining of the sections of the embryonic mandible regions was performed at the bell stage. Protein expression and signaling pathways in a mouse-derived ameloblast-like cell line (LS8) exposed to fluoride or a Jun N-terminal kinase (JNK) inhibitor were compared to those in control cells without exposure. CK1α and proteins of the JNK signaling pathways were assayed by quantitative real-time PCR and Western blotting. Mice of the F group developed dental fluorosis. Scanning electron microscopy showed a significant reduction in the degree of mineralization in the F group mice, which manifested as thin, loosely arranged, and disorganized enamel rods. Additional analysis revealed that the expression of CK1α in the F group was significantly elevated compared with that in the control group; LS8 cells responded to fluoride by upregulation of CK1α expression through the JNK pathway. Our findings identified the potential effects of CK1α on fluorosis using a mouse model and revealed that a high fluoride level increases the expression of CK1α and that JNK can be a key regulatory factor in CK1α expression.

Calcium relieves fluoride-induced bone damage through the PI3K/AKT pathway

Bone is the main target of fluorosis, and it has been perfectly elaborated that a moderate dosage of calcium (Ca) can alleviate bone fluorosis. However, whether Ca can alleviate fluorosis through the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT) signaling pathway has not yet been reported. Hence, we evaluated the histopathological structure, the imbalance of the biochemical index of bone metabolism, and the expression levels of PI3K/AKT apoptosis signaling pathway-related genes in rats treated with sodium fluoride (NaF, F) and/or calcium carbonate (CaCO3) for 120 days. Our results suggest that 100 mg L-1 NaF induced histopathological injury as alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (StrACP) activity increased, with a decrease in the serum Ca levels (p < 0.05). Moreover, the results of qRT-PCR and western blotting showed that F increased the expression levels of transglutaminase 2 (TGM2), focal adhesion kinase (FAK), PI3K, AKT, forkhead box O1 (Foxo1), Bcl-2 interacting mediator of cell death (BIM), Bcl2-associated x protein (Bax) and Caspase 3 (p < 0.05, p < 0.01). It also decreased the expression of AnnexinA5 (Anxa5), 3'-phosphoinositide-dependent kinase 1 (PDK1) and B-cell lymphoma-2 (Bcl-2) (p < 0.05, p < 0.01), which finally activated the PI3K/AKT pathway. On the other hand, CaCO3 supplementation reversed the histopathological injury along with the levels of ALP, StrACP and serum Ca, alleviating the gene expression levels of PI3K/AKT pathway-related markers. Altogether, we can conclude that CaCO3 supplementation mitigated F-induced bone damage via the PI3K/AKT signaling pathway.

Selective inhibitors for JNK signalling: a potential targeted therapy in cancer

c-Jun N-terminal kinase (JNK) signalling regulates both cancer cell apoptosis and survival. Emerging evidence show that JNK promoted tumour progression is involved in various cancers, that include human pancreatic-, lung-, and breast cancer. The pro-survival JNK oncoprotein functions in a cell context- and cell type-specific manner to affect signal pathways that modulate tumour initiation, proliferation, and migration. JNK is therefore considered a potential oncogenic target for cancer therapy. Currently, designing effective and specific JNK inhibitors is an active area in the cancer treatment. Some ATP-competitive inhibitors of JNK, such as SP600125 and AS601245, are widely used in vitro; however, this type of inhibitor lacks specificity as they indiscriminately inhibit phosphorylation of all JNK substrates. Moreover, JNK has at least three isoforms with different functions in cancer development and identifying specific selective inhibitors is crucial for the development of targeted therapy in cancer. Some selective inhibitors of JNK are identified; however, their clinical studies in cancer are relatively less conducted. In this review, we first summarised the function of JNK signalling in cancer progression; there is a focus on the discussion of the novel selective JNK inhibitors as potential targeting therapy in cancer. Finally, we have offered a future perspective of the selective JNK inhibitors in the context of cancer therapies. We hope this review will help to further understand the role of JNK in cancer progression and provide insight into the design of novel selective JNK inhibitors in cancer treatment.

Integrated Analysis of miRNA-mRNA Interaction Network in Porcine Granulosa Cells Undergoing Oxidative Stress

Oxidative stress (OS), a common intracellular phenomenon induced by excess reactive oxygen species (ROS) generation, has been shown to be associated with mammalian ovarian follicular development blockage and granulosa cell (GC) impairment. However, the mechanism involved in these effects remains unknown, and the effect of OS on the transcriptome profiles in porcine GCs has not been fully characterized. In this study, we found that hydrogen peroxide-mediated oxidative stress induced porcine GC apoptosis and impaired cell viability. Moreover, RNA-seq analysis showed that oxidative stress induced dramatic changes in gene expression in porcine GCs. A total of 2025 differentially expressed genes (DEGs) were identified, including 1940 DEmRNAs and 55 DEmiRNAs. Functional annotation showed that the DEGs were mainly associated with cell states and function regulation. In addition, multiple hub genes (FOXO1, SOD2, BMP2, DICER1, BCL2L11, FZD4, ssc-miR-424, and ssc-miR-27b) were identified by constructing protein-protein interaction and DEmiRNA-DEmRNA regulatory networks. Furthermore, a gene-pathway-function coregulatory network was established and demonstrated that these hub genes were enriched in FoxO, TGF-β, Wnt, PIK3-Akt, MAPK, and cAMP signaling pathways, which play important roles in regulating cell apoptosis, cell proliferation, stress responses, and hormone secretion. The current research provides a comprehensive perspective of the effects of oxidative stress on porcine GCs and also identifies potential therapeutic targets for oxidative stress-induced female infertility.

FoxO1 Overexpression Ameliorates TNF-α-Induced Oxidative Damage and Promotes Osteogenesis of Human Periodontal Ligament Stem Cells via Antioxidant Defense Activation

Periodontitis is a chronic disease that includes the pathologic loss of periodontal tissue and alveolar bone. The inflammatory environment in periodontitis impairs the osteogenic differentiation potential and depresses the regeneration capacity of human periodontal ligament stem cells (hPDLSCs). Since Forkhead box protein O1 (FoxO1) plays an important role in redox balance and bone formation, we investigated the role of FoxO1 in oxidative stress resistance and osteogenic differentiation in an inflammatory environment by overexpressing FoxO1 in hPDLSCs. First, we found that FoxO1 overexpression reduced reactive oxygen species (ROS) accumulation, decreased malondialdehyde (MDA) levels, and elevated antioxidant potential under oxidative condition. Next, the overexpression of FoxO1 protected hPDLSCs against oxidative damage, which involved stabilization of the mitochondrial membrane potential. Third, overexpressed FoxO1 promoted extracellular matrix (ECM) mineralization and increased the expression of the osteogenic markers Runx2 and SP7 in the inflammatory environment. These results indicated that FoxO1 overexpression in hPDLSCs has an anti-inflammatory effect, increases antioxidative capacity, and positively regulates osteogenesis in a mimicked inflammatory environment.

JNK signaling in cancer cell survival

c-Jun N-terminal kinase (JNK) is involved in cancer cell apoptosis; however, emerging evidence indicates that this Janus signaling promotes cancer cell survival. JNK acts synergistically with NF-κB, JAK/STAT, and other signaling molecules to exert a survival function. JNK positively regulates autophagy to counteract apoptosis, and its effect on autophagy is related to the development of chemotherapeutic resistance. The prosurvival effect of JNK may involve an immune evasion mechanism mediated by transforming growth factor-β, toll-like receptors, interferon-γ, and autophagy, as well as compensatory JNK-dependent cell proliferation. The present review focuses on recent advances in understanding the prosurvival function of JNK and its role in tumor development and chemoresistance, including a comprehensive analysis of the molecular mechanisms underlying JNK-mediated cancer cell survival. There is a focus on the specific "Yin and Yang" functions of JNK1 and JNK2 in the regulation of cancer cell survival. We highlight recent advances in our knowledge of the roles of JNK in cancer cell survival, which may provide insight into the distinct functions of JNK in cancer and its potential for cancer therapy.

The Contribution of Fluoride to the Pathogenesis of Eye Diseases: Molecular Mechanisms and Implications for Public Health

This study provides diverse lines of evidence demonstrating that fluoride (F) exposure contributes to degenerative eye diseases by stimulating or inhibiting biological pathways associated with the pathogenesis of cataract, age-related macular degeneration and glaucoma. As elucidated in this study, F exerts this effect by inhibiting enolase, τ-crystallin, Hsp40, Na⁺, K⁺-ATPase, Nrf2, γ -GCS, HO-1 Bcl-2, FoxO1, SOD, PON-1 and glutathione activity, and upregulating NF-κB, IL-6, AGEs, HsP27 and Hsp70 expression. Moreover, F exposure leads to enhanced oxidative stress and impaired antioxidant activity. Based on the evidence presented in this study, it can be concluded that F exposure may be added to the list of identifiable risk factors associated with pathogenesis of degenerative eye diseases. The broader impact of these findings suggests that reducing F intake may lead to an overall reduction in the modifiable risk factors associated with degenerative eye diseases. Further studies are required to examine this association and determine differences in prevalence rates amongst fluoridated and non-fluoridated communities, taking into consideration other dietary sources of F such as tea. Finally, the findings of this study elucidate molecular pathways associated with F exposure that may suggest a possible association between F exposure and other inflammatory diseases. Further studies are also warranted to examine these associations.

NaF Reduces KLK4 Gene Expression by Decreasing Foxo1 in LS8 Cells

Decreased expression and increased phosphorylation of Forkhead box o1 (Foxo1) in ameloblasts were observed both in vivo and in vitro when treated by fluoride. The present study aims to investigate the possible relationship between Foxo1 and enamel matrix proteinases, matrix metalloproteinase 20 (MMP20), and kallikrein 4 (KLK4), in NaF-treated ameloblasts. Ameloblast-like cells (LS8 cells) were exposed to NaF at selected concentration (0/2 mM) for 24 h. Gene overexpression and silencing experiments were used to up- and down-regulate Foxo1 expression. The expression levels of Foxo1, MMP20, and KLK4 were detected by quantitative real-time PCR and western blot. Dual luciferase reporter assay was performed to evaluate the regulation of Foxo1 on the transcriptional activity of KLK4 promoter. The results showed that KLK4 expression was decreased in LS8 cells treated by NaF, while MMP20 expression was not changed. Foxo1 activation led to significantly up-regulation of KLK4 in LS8 cells under NaF condition. Knockout of Foxo1 markedly decreased klk4 expression in mRNA level, and intensified inhibition occurred in LS8 cells when combined with NaF treatment. However, the variation trend of MMP20 was not clear. Dual luciferase reporter assay showed that Foxo1 activation enhanced the transcriptional activity of KLK4 promoter. These findings suggest that the decrease of Foxo1 expression induced by high fluoride was a cause for low KLK4 expression.

Xihuang Pill Induces Apoptosis of Human Glioblastoma U-87 MG Cells via Targeting ROS-Mediated Akt/mTOR/FOXO1 Pathway

Xihuang pill (XHP), a traditional Chinese herbal formula, has long been used as an effective agent against multiple tumors. The aim of this study is to evaluate the effects of XHP on the growth inhibition and apoptosis in glioblastoma U-87 MG cells. Gas chromatography-mass spectrometry (GC-MS) was performed for constituent analysis of XHP. Cell viability, cell cycle arrest, generation of reactive oxygen species (ROS), and apoptosis were measured by CCK-8 assay, PI/RNase staining, DCFH-DA assay, TUNEL assay, Annexin V-FITC/PI double staining, and JC-1 assay, respectively. The role of XHP in the regulation of Akt/mTOR/FOXO1 interaction was clarified by using Western Blotting (WB), immunofluorescence (IF), pharmacological inhibitor or antioxidant, and siRNA silencing. The results suggested that XHP could inhibit U-87 MG cells growth and arrest cells in S-phase cell cycle significantly and that the generation of ROS, collapse of mitochondrial membrane potential, enhancement of Bax/Bcl-xL ratio, and reduction of the precursor forms of caspase-9 and caspase-3 caused by XHP prompted that a ROS-mediated mitochondria-dependent apoptosis was possibly involved. Furthermore, XHP affected the Akt/mTOR/FOXO1 pathway via inhibiting the phosphorylation of Akt, mTOR, and FOXO1 and increasing both prototype and nuclear translocation of FOXO1. Inhibition of Akt, mTOR, and FOXO1 by specific inhibitors or siRNA could interpose the apoptotic induction. In conclusion, we demonstrate for the first time that XHP may regulate glioblastoma U-87 MG cell apoptosis via ROS-mediated Akt/mTOR/FOXO1 pathway.

Daidzein induces choriocarcinoma cell apoptosis in a dose-dependent manner via the mitochondrial apoptotic pathway

Choriocarcinoma is a malignant gestational trophoblastic disease and relapse or drug resistance occurs in ~25% of gestational trophoblastic tumors. Cell apoptosis serves a role in the progression from hydatidiform mole to persistent gestational trophoblastic disease. It has been demonstrated that daidzein [7‑hydroxy‑3‑(4‑hydroxyphenyl)‑4H‑chromen‑4‑one] may induce apoptosis in a number of cancer types via the mitochondrial apoptotic pathway by altering the B‑cell lymphoma (Bcl)‑2/Bcl‑2 associated X, apoptosis regulator (Bax) ratio, and activating the caspase cascade. Daidzein also serves a role in regulation of production of human chorionic gonadotropin in trophoblast cells and inhibition of cell proliferation. However, few reports have been published regarding the effect of daidzein on apoptosis in choriocarcinoma. Therefore, in the present study, JAR and JEG‑3 human gestational choriocarcinoma cells were used to investigate the effect of daidzein on apoptosis of choriocarcinoma cells. Treatment with daidzein for 48 h reduced cell viability in a dose‑dependent manner. The percentages of early and late apoptotic cells also increased following treatment with daidzein in a dose‑dependent manner, with the number of late apoptotic cells increasing more prominently. Furthermore, treatment with daidzein led to apoptosis‑associated alterations in nuclear morphology of JAR and JEG-3 cells. Expression levels of cleaved poly(ADP‑ribose) polymerase, cleaved caspase‑3 and cleaved caspase‑9 increased following treatment with daidzein, whereas the Bcl‑2/Bax ratio decreased in a dose‑dependent manner. In conclusion, the results of the present study demonstrate that daidzein may induce apoptosis of choriocarcinoma cells in a dose‑dependent manner via the mitochondrial apoptotic pathway.