Estrogenic disruption effects and formation mechanisms of transformation products during photolysis of preservative parabens.

The ubiquitous presence of emerging contaminants (ECs) in the environment and their associated adverse effects has raised concerns about their potential risks. The increased toxicity observed during the environmental transformation of ECs is often linked to the formation of their transformation products (TPs). However, comprehension of their formation mechanisms and contribution to the increased toxicity remains an unresolved challenge. To address this gap, by combining quantum chemical and molecular simulations with photochemical experiments in water, this study investigated the formation of TPs and their molecular interactions related to estrogenic effect using the photochemical degradation of benzylparaben (BZP) preservative as a representative example. A non-targeted analysis was carried out and three previously unknown TPs were identified during the transformation of BZP. Noteworthy, two of these novel TPs, namely oligomers BZP-o-phenol and BZP-m-phenol, exhibited higher estrogenic activities compared to the parent BZP. Their IC50 values of 0.26 and 0.50 µM, respectively, were found to be lower than that of the parent BZP (6.42 µM). The binding free energies (ΔGbind) of BZP-o-phenol and BZP-m-phenol (-29.71 to -23.28 kcal·mol-1) were lower than that of the parent BZP (-20.86 kcal·mol-1), confirming their stronger binding affinities toward the estrogen receptor (ER) α-ligand binding domain. Subsequent analysis unveiled that these hydrophobic residues contributed most favorably to ER binding, with van der Waals interactions playing a significant role. In-depth examination of the formation mechanisms indicated that these toxic TPs primarily originated from the successive cleavage of ester bonds (OCH2C6H5 and COO group), followed by their combination with BZP*. This study provides valuable insight into the mechanisms underlying the formation of toxic TPs and their binding interactions causing the endocrine-disrupting effects. It offers a crucial framework for elucidating the toxicological patterns of ECs with similar structures.

Erratum: EPHB4 Regulates the Proliferation and Metastasis of Oral Squamous Cell Carcinoma through the HMGB1/NF-κB Signalling Pathway: Erratum.

[This corrects the article DOI: 10.7150/jca.59331.].

Ebselen restores peri-implantitis-induced osteogenic inhibition via suppressing BMSCs ferroptosis.

It is hard to reconstruct bone defects in peri-implantitis due to osteogenesis inhibited by excessive reactive oxygen species (ROS). Ferroptosis, a recently identified regulated cell death characterized by iron- and ROS- dependent lipid peroxidation, provides us with a new explanation. Our study aims to explore whether ferroptosis is involved in peri-implantitis-inhibited osteogenesis and confirm ebselen, an antioxidant with glutathione peroxidase (GPx)-like activity, could inhibit ferroptosis and promote osteogenesis in peri-implantitis. In this study, we used LPS to mimic the microenvironment of peri-implantitis. The osteogenic differentiation of bone-marrow-derived mesenchymal stem cells (BMSCs) was assessed by alkaline phosphatase (ALP), Alizarin Red S, and mRNA and protein expression of osteogenic-related markers. Ferroptosis index analysis included iron metabolism, ROS production, lipid peroxidation and mitochondrial morphological changes. Iron overload, reduced antioxidant capability, excessive ROS, lipid peroxidation and the characteristic mitochondrial morphological changes of ferroptosis were observed in LPS-treated BMSCs, and adding Ferrostatin-1 (Fer-1) restored the inhibitory effect of ferroptosis on osteogenic differentiation of BMSCs. Furthermore, ebselen ameliorated LPS-induced ferroptosis and osteogenic inhibition, which were reversed by erastin. Our results demonstrated that ferroptosis is involved in osteogenic inhibition in peri-implantitis and ebselen could attenuate osteogenic dysfunction of BMSCs via inhibiting ferroptosis.

The influences of PEG-functionalized graphdiyne on cell growth and osteogenic differentiation of bone marrow mesenchymal stem cells.

Guided bone regeneration (GBR) is a frequently used technique for patients with insufficient alveolar bone. The discovery of bone substitutes that can enhance osteogenesis is critical for GBR. Graphdiyne (GDY), a newly discovered carbon-based nanomaterial, has been recognized as the most stable allotrope of acetylene carbon and is anticipated to be able to promote osteogenesis. Whereas it still remains unknown whether it could enhance osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). In this study, GDY was modified with polyethylene glycol (PEG) and the influences of GDY-PEG at different concentrations on BMSCs cell growth and osteogenic differentiation were researched for the first time. In this study, we found that GDY-PEG at low concentration possessed premium bio-compatibility and revealed evident facilitation of BMSCs osteogenic differentiation. The cell growth and osteogenic differentiation of BMSCs treated with GDY-PEG were dose-dependent. GDY-PEG at 1 µg/mL demonstrated the optimal promoting effects of BMSCs osteogenic differentiation. Moreover, the regulating effect of BMSCs osteogenic differentiation by GDY-PEG might be associated with the Wnt/ß-catenin signaling pathway. In all, the present study indicated a novel application of GDY in promoting bone tissue regeneration, providing a novel biomaterial for bone augmentation in clinics.

Nanostructured Graphdiyne: Synthesis and Biomedical Applications.

Graphdiyne (GDY) is a 2D carbon allotrope that features a one-atom-thick network of sp- and sp2-hybridized carbon atoms with high degrees of π conjugation. Due to its distinct electronic, chemical, mechanical, and magnetic properties, GDY has attracted great attention and shown great potential in various fields, such as catalysis, energy storage, and the environment. Preparation of GDY with various nanostructures, including 0D quantum dots, 1D nanotubes/nanowires/nanoribbons, 2D nanosheets/nanowalls/ordered stripe arrays, and 3D nanospheres, greatly improves its function and has propelled its applications forward. High biocompatibility and stability make GDY a promising candidate for biomedical applications. This review introduces the latest developments in fabrication of GDY-based nanomaterials with various morphologies and summarizes their propective use in the biomedical domain, specifically focusing on their potential advantages and applications for biosensing, cancer diagnosis and therapy, radiation protection, and tissue engineering.

The Differential Metabolic Response of Oral Squamous Cell Carcinoma Cells and Normal Oral Epithelial Cells to Cisplatin Exposure.

Metabolic reprogramming is one of the hallmarks of a tumor. It not only promotes the development and progression of tumor but also contributes to the resistance of tumor cells to chemotherapeutics. The difference in the metabolism between drug-resistant and sensitive tumor cells indicates that drug-resistant tumor cells have experienced metabolic adaptation. The metabolic response induced by chemotherapy is dynamic, but the early metabolic response of tumor cells to anticancer drugs and the effect of an initial response on the development of drug resistance have not been well studied. Early metabolic intervention may prevent or slow down the development of drug resistance. The differential metabolic responses of normal cells and tumor cells to drugs are unclear. The specific metabolites or metabolic pathways of tumor cells to chemotherapeutic drugs can be used as the target of metabolic intervention in tumor therapy. In this study, we used comparative metabolomics to analyze the differential metabolic responses of oral cancer cells and normal oral epithelial cells to short-term cisplatin exposure, and to identify the marker metabolites of early response in oral cancer cells. Oral cancer cells showed a dynamic metabolic response to cisplatin. Seven and five metabolites were identified as specific response markers to cisplatin exposure in oral cancer cell SCC-9 and normal oral epithelial cell HOEC, respectively. Glyoxylate and dicarboxylate metabolism and fructose, malate, serine, alanine, sorbose and glutamate were considered as specific enriched metabolic pathways and biomarkers of SCC-9 cells in response to cisplatin, respectively. The existence of differential metabolic responses lays a foundation for tumor chemotherapy combined with metabolic intervention.

Selenomethionine protects oxidative-stress-damaged bone-marrow-derived mesenchymal stem cells via an antioxidant effect and the PTEN/PI3K/AKT pathway.

Dental implant surgery is currently a routine therapy for the repair of missing dentition or dentition defects. Both clinical and basic research have elucidated that oxidative stress caused by the accumulation of reactive oxygen species (ROS) for various reasons impairs the process of osteointegration after dental implantation. Therefore, the osteogenic micro-environment must be ameliorated to decrease the damage caused by oxidative stress. Selenomethionine (SEMET) has been reported to play an important role in alleviating oxidative stress and accelerating cell viability and growth. However, it remains unclear whether it exerts protective effects on bone-marrow-derived mesenchymal stem cells (BMSCs) under oxidative stress. In this study, we explored the influence of selenomethionine on the viability and osteogenic differentiation of BMSCs under oxidative stress and the underlying mechanisms. Results showed that 1 µM selenomethionine was the optimum concentration for BMSCs under H2O2 stimulation. H2O2-induced oxidative stress suppressed the viability and osteogenic differentiation of BMSCs, manifested by the increases in ROS production and cell apoptosis rates, and by the decrease of osteogenic differentiation-related markers. Notably, the aforementioned oxidative damage and osteogenic dysfunction induced by H2O2 were rescued by selenomethionine. Furthermore, we found that the PTEN expression level was suppressed and its downstream PI3K/AKT pathway was activated by selenomethionine. However, when PTEN was stimulated, the PI3K/AKT pathway was down-regulated, and the protective effects of selenomethionine on BMSC osteogenic differentiation diminished, while the inhibition of PTEN up-regulated the protective effects of selenomethionine. Together, these results revealed that selenomethionine could attenuate H2O2-induced BMSC dysfunction through an antioxidant effect, modulated via the PTEN/PI3K/AKT pathway, suggesting that selenomethionine is a promising antioxidant candidate for reducing oxidative stress during the process of dental implant osteointegration.

EPHB4 Regulates the Proliferation and Metastasis of Oral Squamous Cell Carcinoma through the HMGB1/NF-κB Signalling Pathway.

Background: Malignant proliferation and cervical lymphatic metastasis restrict the prognosis of oral squamous cell carcinoma (OSCC). Erythropoietin-producing human hepatocellular B4 (EPHB4) regulates a series of tumour functions involving tumourigenesis, cancer cell attachment and metastasis. However, the mechanism of EphB4 regulating the malignant progression of OSCC has not been fully elucidated. Methods: EPHB4 expression was analysed in 65 OSCC samples and adjacent noncancerous tissues through immunohistochemistry (IHC). siRNA and overexpression plasmids were transfected into OSCC cells to modify EPHB4 expression, and then, regulatory functions were explored in vitro and in vivo. Co-immunoprecipitation (Co-IP) and mass spectrometry were applied to detect proteins interacting with EPHB4. Subsequently, protein stability assays and NF-κB pathway inhibition assays were used to verify the regulation of EPHB4, high-mobility group box 1 (HMGB1) and nuclear factor-κB (NF-κB) activation. Results: EPHB4 was found to be highly expressed in OSCC tissues, which was related to tumour stage and lymphatic metastasis and resulted in a poor prognosis. Cellular experiments and mouse tongue xenograft models further confirmed that high EPHB4 expression promoted the proliferation and metastasis of OSCC tumours. Mechanistically, co-IP and mass spectrometry studies indicated that EPHB4 could bind to HMGB1 and maintain HMGB1 stability. Downregulation of HMGB1 inhibited the proliferation and metastasis of OSCC cells and inhibited NF-κB phosphorylation activation but did not affect EPHB4 expression. Conclusion: This study revealed the mechanism by which EPHB4 promotes the proliferation and metastasis of OSCC by activating the HMGB1-mediated NF-κB signalling pathway, which can be exploited as a novel marker or therapeutic target to control metastasis and improve the survival rate of OSCC.

Effect of magnetic graphene oxide on cellular behaviors and osteogenesis under a moderate static magnetic field.

The biological behaviors of magnetic graphene oxide (MGO) in a static magnetic field (SMF) are unknown. The current study is to investigate the cellular behaviors, osteogenesis and the mechanism in BMSCs treated with MGO combined with an SMF. Results showed that the synthetic MGO particles were bio-compatible and could significantly improve the osteogenesis of BMSCs under SMFs, as verified by elevated alkaline phosphatase activity, mineralized nodule formation, and expressions of mRNA and protein levels. Under SMF at the same intensity, the addition of graphene oxide to Fe3O4 could increase the osteogenic ability of BMSCs. The Wnt/ß-catenin pathway was indicated to be related to the MGO-driven osteogenic behavior of the BMSCs under SMF. Taken together, our findings suggested that MGO under an SMF could promote osteogenesis in BMSCs through the Wnt/ß-catenin pathway and hence should attract more attention for practical applications in bone tissue regeneration.

Metabolomics study reveals the potential evidence of metabolic reprogramming towards the Warburg effect in precancerous lesions.

Background: Most tumors have an enhanced glycolysis flux, even when oxygen is available, called the aerobic glycolysis or the Warburg effect. Metabolic reprogramming promotes cancer progression, and is even related to the tumorigenesis. However, it is not clear whether the observed metabolic changes act as a driver or a bystander in cancer development. Methods: In this study, the metabolic characteristics of oral precancerous cells and cervical precancerous lesions were analyzed by metabolomics, and the expression of glycolytic enzymes in cervical precancerous lesions was evaluated by RT-PCR and Western blot analysis. Results: In total, 115 and 23 metabolites with reliable signals were identified in oral cells and cervical tissues, respectively. Based on the metabolome, oral precancerous cell DOK could be clearly separated from normal human oral epithelial cells (HOEC) and oral cancer cells. Four critical differential metabolites (pyruvate, glutamine, methionine and lysine) were identified between DOK and HOEC. Metabolic profiles could clearly distinguish cervical precancerous lesions from normal cervical epithelium and cervical cancer. Compared with normal cervical epithelium, the glucose consumption and lactate production increased in cervical precancerous lesions. The expression of glycolytic enzymes LDHA, HK II and PKM2 showed an increased tendency in cervical precancerous lesions compared with normal cervical epithelium. Conclusions: Our findings suggest that cell metabolism may be reprogrammed at the early stage of tumorigenesis, implying the contribution of metabolic reprogramming to the development of tumor.

Host Immune Response Triggered by Graphene Quantum-Dot-Mediated Photodynamic Therapy for Oral Squamous Cell Carcinoma.

INTRODUCTION: With the innovation of photosensitizers, photodynamic therapy is now widely used in antitumor detection and treatment. Graphene quantum dots (GQDs) are proposed as a promising alternative photosensitizer due to their high biocompatibility, specific photoactivity, and strong tumor concentration. However, the changes in host immunity triggered by GQDs have only rarely been reported. METHODS: In this work, GQDs as photosensitizers were conjugated to polyethylene glycol (PEG) to enhance solubility and blood circulation. The phototoxicity of the resulting GQD-PEG nanomaterials was then detected in vitro and in vivo. The antitumor immunity triggered by GQD-PEG under irradiation was further evaluated in an oral squamous cell carcinoma animal model. RESULTS: The obtained GQD-PEG nanomaterials exhibited low cytotoxicity, good solution stability, and excellent endocytosis. Both in vitro and in vivo, all demonstrated strong ablation for oral squamous cell carcinoma under irradiation. Meanwhile, host-immunity-related CD8+ T cells (cytotoxic T lymphocytes) and proinflammatory cytokines, including IFN-γ and TNF-α, were significantly increased after photo-activated antitumor activity. CONCLUSION: These results highlight the dominant role of GQD-PEG in photodynamic therapy and could have significant implications for further combination therapy as a promising antitumor immune response strategy triggered by nanomaterials.

Upregulation of Circular RNA circATRNL1 to Sensitize Oral Squamous Cell Carcinoma to Irradiation.

Accumulating evidence has demonstrated that circular RNAs (circRNAs) play important roles in regulating gene expression involved in tumor development. However, the role of circRNAs in modulating the radiosensitivity of oral squamous cell carcinoma (OSCC) and its potential mechanisms have not been documented. We performed high-throughput RNA sequencing (RNA-seq) to investigate the circRNA expression profile in OSCC patients and discovered that the circATRNL1 expression was significantly downregulated and closely related to tumor progression. The circATRNL1 was structurally validated via Sanger sequencing, RNase R treatment, and specific convergent and divergent primer amplification. Importantly, the expression levels of circATRNL1 decreased after irradiation treatment, and upregulation of circATRNL1 enhanced the radiosensitivity of OSCC through suppressing proliferation and the colony survival fraction, inducing apoptosis and cell-cycle arrest. Moreover, we observed that circATRNL1 could directly bind to microRNA-23a-3p (miR-23a-3p) and relieve inhibition for the target gene PTEN. In addition, the tumor radiosensitivity-promoting effect of circATRNL1 overexpression was blocked by miR-23a-3p in OSCC. Further experiments also showed that PTEN can reverse the inhibitory effect of OSCC radiosensitivity triggered by miR-23a-3p. We concluded that circANTRL1 may function as the sponge of miR-23a-3p to promote PTEN expression and eventually contributes to OSCC radiosensitivity enhancement. This study indicates that circANTRL1 may be a novel therapeutic target to improve the efficiency of radiotherapy in OSCC.

Concentration-dependent cellular behavior and osteogenic differentiation effect induced in bone marrow mesenchymal stem cells treated with magnetic graphene oxide.

The scaffold-free cell sheet plays an important role in stem-cell-based regeneration. Graphene oxide (GO) endows nanoparticles (NPs) with special characteristics and therefore has attracted increasing attention in recent years. However, the existence of toxicity in GO and its derivatives limits their ability to promote osteogenic differentiation. Magnetic graphene oxide (MGO), a novel combination of Fe3 O4 and GO with diverse unique properties, has not been studied in bone tissue engineering. In this study, MGO was fabricated, and the previously undiscovered relationships-including cellular behavior and the effects of osteogenic differentiation and related mechanisms of MGO in rat bone-marrow-derived mesenchymal stem cells (BMSCs)-were investigated for the first time. Here, we found that MGO was not only biocompatible at low concentrations, but also could significantly accelerate osteogenic differentiation in BMSCs. Both the cellular behavior and bone-formation differentiation in BMSCs treated with MGO showed concentration-dependent characteristics. In addition, the regulation of osteogenic differentiation in BMSCs treated with MGO might be involved with the Wnt/ß-catenin and BMP signaling pathways. Furthermore, MGO demonstrated a better ability for osteogenic differentiation in BMSCs than did GO. The current work indicated a significant use for MGO nanocomposite scaffolds in biocompatibility and bone regeneration, which could provide new insight into bone regeneration in the future.

Dose-dependent cytotoxicity induced by pristine graphene oxide nanosheets for potential bone tissue regeneration.

This study was aimed to investigate the toxic effects of pristine graphene oxide (GO) nanosheets on bone-marrow-derived mesenchymal stem cells (BMSCs), a type of traditional seed cells in tissue regeneration engineering. First, a GO suspension was prepared and characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, and Raman shifts. Then, rat BMSCs were isolated and characterized. Subsequently, cell proliferation, membrane integrity, cell cycle, cell apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) were measured. In addition, relevant proteins of the mitochondrial apoptotic pathway and autophagy were analyzed. Our results showed that a high concentration of GO inhibited cell viability and membrane integrity, while cell apoptosis and cell-cycle arrest were induced by GO. Further, GO significantly increased ROS generation and MMP loss with an upregulation of Cleaved Caspase-3, LC3-II/I, and Beclin-1 and a downregulation of Bcl-2 and Caspase3. We concluded that the toxic effects of GO on BMSCs occurred in a dose-dependent manner via the mitochondrial apoptotic pathway and autophagy.

Ebselen rescues oxidative-stress-suppressed osteogenic differentiation of bone-marrow-derived mesenchymal stem cells via an antioxidant effect and the PI3K/Akt pathway.

BACKGROUND: Patients with metabolic bone diseases often have high risk of titanium implant failure due to compromised bone regeneration ability. Clinical evidence indicates that the poor osteogenic ability is partly because of excessive oxidative stress. To date, specific treatments for these patients are urgently needed. Ebselen, a non-toxic organoselenium compound, is reported to be a potent antioxidant agent. In this study, we hypothesized that ebselen exerted protective effects on osteogenic differentiation of bone-marrow-derived mesenchymal stem cells (BMSCs) under oxidative stress. METHODS: BMSCs were isolated from SD rats, and their morphology and multiple differentiation abilities were characterized. Proliferation rates of BMSCs treated with different concentrations of ebselen were analyzed. Then BMSCs were pretreated by hydrogen peroxide (H2O2), after which ebselen at different concentrations (0, 1, 5, 10 µM) was added, alkaline phosphatase (ALP) activity, mineralization and osteogenic-related protein levels were evaluated and an optimum concentration of ebselen was selected. Subsequently, intracellular reactive oxygen species (ROS) generation and the role of the PI3K/AKT pathway were also investigated. RESULTS: Ebselen within a proper range could promote the proliferation of BMSCs. H2O2-induced oxidative stress suppressed osteogenic differentiation of BMSCs, which was verified by the decrease in ALP activity, calcium deposition, Runx2 and ß-catenin expression. However, ebselen could alleviate osteogenic dysfunction of BMSCs. We also observed that ebselen reduced ROS accumulation in H2O2-pretreated BMSCs. Moreover, the pro-osteogenic effects afforded by ebselen were almost abolished by the Akt inhibitor. CONCLUSION: We concluded that ebselen could attenuate osteogenic dysfunction of BMSCs induced by H2O2 through an antioxidant effect and the activation of the PI3K/Akt pathway, suggesting that ebselen has a potential therapeutic effect for patients with metabolic bone diseases.

LncRNA GAS5 suppresses proliferation, migration, invasion, and epithelial-mesenchymal transition in oral squamous cell carcinoma by regulating the miR-21/PTEN axis.

Growth-arrest-specific transcript 5 (GAS5) functions as a tumor suppressor in a variety of cancers. GAS5 has been reported to be down-regulated in oral squamous cell carcinoma (OSCC). The aim of this study was to investigate the mechanisms of how GAS5 acts as a tumor suppressor in OSCC. qRT-PCR, cell viability, wound-healing, and transwell assays showed that knockdown of GAS5 increased miR-21 expression and promoted proliferation, migration, invasion, and epithelial-mesenchymal transition of OSCC cells. In contrast, overexpression of GAS5 showed the opposite effects. Furthermore, miR-21 overexpression reversed the effect of GAS5. Western blot showed that knockdown of GAS5 suppressed PTEN, while phosphorylation of Akt was promoted. PCNA, cyclinD1, and Ki-67 were up-regulated, indicating enhanced proliferation. E-cadherin was down-regulated, while N-cadherin, vimentin, and snail1 were increased, indicating augmented epithelial-mesenchymal transition. Overexpression of GAS5 regulated these proteins inversely. Overexpression of miR-21 reversed the effect of GAS5 on these proteins. Taken together, GAS5 suppresses proliferation, migration, invasion, and epithelial-mesenchymal transition in OSCC through the miR-21/PTEN axis and might be a novel therapeutic target for OSCC.

Silencing PFKP inhibits starvation-induced autophagy, glycolysis, and epithelial mesenchymal transition in oral squamous cell carcinoma.

The tumor starvation microenvironment plays a pivotal role in the malignant progression of cancer, which is closely related to autophagy, glycolysis, and epithelial mesenchymal transition (EMT). Nevertheless, the underlying mechanisms of the starvation-mediated malignant phenotype are still not well documented. In this study, we aimed to investigate the effect of starvation on glycolysis, autophagy, and EMT in OSCC and to further elucidate the key metabolic modulator. The results showed that starvation can induce autophagy, EMT, and enhanced glycolysis in OSCC cells. We determined that the expression of the key glycolytic enzyme phosphofructokinase-platelet (PFKP) obviously increased under starvation conditions and that PFKP knockdown inhibited starvation-mediated glycolysis, autophagy and EMT in OSCC cells. Moreover, we confirmed that PFKP knockdown inhibited OSCC xenograft growth in vivo. In addition, PFKP expression was significantly increased in OSCC patients and its upregulation was associated with the presence of tumor pathological differentiation and lymph node metastasis. Taken together, our findings demonstrate that PFKP is necessary for starvation-mediated autophagy, glycolysis, and EMT, thereby promoting the malignant progression of OSCC.

Deregulation of Hexokinase II Is Associated with Glycolysis, Autophagy, and the Epithelial-Mesenchymal Transition in Tongue Squamous Cell Carcinoma under Hypoxia.

The glycolytic enzyme Hexokinase (HKII) participates in tumor glycolysis and the progression of various cancers, but its clinicopathological effect on the progression of tongue squamous cell carcinoma (TSCC) and its role in glycolysis, autophagy, and the epithelial-mesenchymal transition of TSCC in a hypoxic microenvironment remain unknown. Our results showed that HKII expression was dramatically increased in TSCC tissues and that its upregulation was significantly associated with the presence of pathological differentiation, lymph node metastasis, and clinical stage. The level of autophagy-specific protein LC3, EMT-related proteins, and the migration and invasion capabilities of TSCC cells all increased under hypoxia. Moreover, hypoxia increased the glucose consumption and lactate production of TSCC cells, and we demonstrated that the expression of the glycolytic key gene HKII was significantly higher than in that of the control group. Notably, the downregulation of HKII resulted in a significant decrease of TSCC cell glucose consumption lactate production and autophagic activity during hypoxia. HKII knockdown blocked the migratory and invasive capacity of TSCC cells and we specifically determined that the EMT ability decreased. Therefore, our findings revealed that the upregulation of HKII enhanced glycolysis and increased autophagy and the epithelial-mesenchymal transition of tongue squamous cell carcinoma under hypoxia.

miR-373-3p Targets DKK1 to Promote EMT-Induced Metastasis via the Wnt/ß-Catenin Pathway in Tongue Squamous Cell Carcinoma.

MicroRNAs (miRNAs) regulate gene expression and at the same time mediate tumorigenesis. miR-373-3p has diverse effects in tumors, but its role in tongue squamous cell carcinoma (TSCC) remains unknown. The purpose of this study is to determine the function of miR-373-3p in the progression of TSCC. Our results brought to light that miR-373-3p is markedly upregulated in clinical TSCC tissues compared with paired adjacent normal tissues and has significant correlation with a more aggressive TSCC phenotype in patients. Gain-of-function and loss-of-function studies revealed that ectopic miR-373-3p overexpression promoted the metastasis of TSCC cells. Notably, Wnt/ß-catenin signaling was hyperactivated in TSCC cells overexpressing miR-373-3p, and this pathway was responsible for the epithelial-mesenchymal transition (EMT) induced by miR-373-3p. Furthermore, miR-373-3p directly targeted and suppressed Dickkopf-1 (DKK1), a negative regulator of the Wnt/ß-catenin signaling cascade. These results demonstrate that, by directly targeting DKK1, miR-373-3p constitutively activated Wnt/ß-catenin signaling, thus promoting the EMT-induced metastasis of TSCC. Taken together, our findings reveal a new regulatory mechanism for miR-373-3p and suggest that miR-373-3p might be a potential target in TSCC therapy.