Cognitive decline in Sprague-Dawley rats induced by neuroplasticity changes after occlusal support loss.

BACKGROUND: Tooth loss is closely related to cognitive impairment, especially affecting cognitive functions involving hippocampus. The most well-known function of the hippocampus is learning and memory, and the mechanism behind is neuroplasticity, which strongly depends on the level of brain-derived neurotrophic factor (BDNF). While research has delved into the possible mechanisms behind the loss of teeth leading to cognitive dysfunction, there are few studies on the plasticity of sensory neural pathway after tooth loss, and the changes in related indicators of synaptic plasticity still need to be further explored. METHODS: In this study, the bilateral maxillary molars were extracted in Sprague-Dawley rats of two age ranges (young and middle age) to establish occlusal support loss model; then, the spatial cognition was tested by Morris Water Maze (MWM). Quantitative real-time PCR (qPCR) and Western Blotting (WB) were used to detect BDNF, AKT, and functional proteins (viz., PSD95 and NMDAR) of hippocampal synapses. Golgi staining was used to observe changes in ascending nerve pathway. IF was used to confirm the location of BDNF and AKT expressed in hippocampus. RESULTS: MWM showed that the spatial cognitive level of rats dropped after occlusal support loss. qPCR, WB, and IF suggested that the BDNF/AKT pathway was down-regulated in the hippocampus. Golgi staining showed the neurons of ascending sensory pathway decreased in numbers. CONCLUSION: Occlusal support loss caused plastic changes in ascending nerve pathway and induced cognitive impairment in rats by down-regulating BDNF and synaptic plasticity.

Prx1/PHB2 axis mediates mitophagy in oral leukoplakia cellular senescence.

BACKGROUND: Oral leukoplakia (OLK) is the most common oral potentially malignant disorder (OPMD), which can be malignantly transformed into oral squamous cell carcinoma (OSCC). Peroxiredoxin1(Prx1) has been predicted to bind to Prohibitin2 (PHB2), which confers to affect OLK progression; however, the mechanism of Prx1/PHB2 mediated mitophagy involved in OLK remains unclear. METHODS: This study aimed to explore the mechanism of the Prx1/PHB2 axis on senescence in OLK through mediating mitophagy. The positive rate of Ki67 and the expression of p21, p16, PHB2, and LC3 in human normal, OLK, and OSCC tissues were detected by immunohistochemical staining. The mitophagy and mitochondrial function changes were then analyzed in Prx1 knockdown and Prx1C52S mutations in dysplastic oral keratinocyte (DOK) cells treated with H2O2. In situ Proximity Ligation Assay combined with co-immunoprecipitation was used to detect the interaction between Prx1 and PHB2. RESULTS: Clinically, the positive rate of Ki67 progressively increased from normal to OLK, OLK with dysplasia, and OSCC. Higher p21, p16, PHB2, and LC3 expression levels were observed in OLK with dysplasia than in normal and OSCC tissues. In vitro, PHB2 and LC3II expression gradually increased with the degree of DOK cell senescence. Prx1/PHB2 regulated mitophagy and affected senescence in H2O2-induced DOK cells. Furthermore, Prx1C52S mutation specifically reduced interaction between Prx1 and PHB2. Prx1Cys52 is associated with mitochondrial reactive oxygen species (ROS) accumulated and cell cycle arrest. CONCLUSION: Prx1Cys52 functions as a redox sensor that binds to PHB2 and regulates mitophagy in the senescence of OLK, suggesting its potential as a clinical target.

Conditional knockout mouse model reveals a critical role of peroxiredoxin 1 in oral leukoplakia carcinogenesis.

Peroxiredoxin 1 (Prx1) is an antioxidant protein that may promote the carcinogenesis in oral leukoplakia (OLK). To investigate the effect of Prx1 on the oral mucosal epithelium of OLK, we generated a Prx1 conditional knockout (cKO) mouse model. The mRNA and gRNA were generated using the clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) technique. An infusion cloning method was used to construct a homologous recombination vector. To obtain the F0 generation mice, fertilized eggs of C57BL/6J mice were microinjected with Cas9 mRNA, gRNA, and a donor vector. Polymerase chain reaction (PCR) amplification and sequencing were used to identify F1 generation mice. Using the cyclization recombination-enzyme-locus of the X-overP1 (Cre-loxP) system, we created a Prx1 cKO mouse model, and the effectiveness of the knockout was confirmed through immunohistochemistry. We examined the influence of Prx1 knockout on the occurrence of OLK in mice by constructing a model of tongue mucosa carcinogenesis induced by 4-nitroquinoline-1-oxide (4NQO). Prx1 modification was present in the F1 generation, as evidenced by PCR amplification and sequencing. Prx1flox/flox: Cre + mice exhibited normal growth and fertility. Immunohistochemical analysis revealed that tongue epithelial cells in Prx1flox/flox: Cre + mice displayed a distinct deletion of Prx1. An examination of the heart, liver, spleen, lung, and kidney tissues revealed no visible histological changes. Histological analysis showed a reduction in the occurrence of the malignant transformation of OLK in the tongue tissues of Prx1flox/flox: Cre + mice. Ki67 immunostaining showed that Prx1 knockout significantly inhibited cell proliferation in the tongue epithelial. Our research developed a conditional knockout mouse model for Prx1. The obtained results provide insights into the function of Prx1 in the development of oral cancer and emphasize its potential as a therapeutic target for precancerous oral lesions.

Tooth loss impairs cognitive function in SAMP8 mice via the NLRP3/Caspase-1 pathway.

OBJECTIVE: Loss of occlusal support due to tooth loss has been indicated as one of the risk factors for Alzheimer's disease. This study aimed to investigate the relationship between tooth loss and cognitive dysfunction and illustrate the role of neuroinflammation in advancing Alzheimer's disease. MATERIALS AND METHODS: Male 5-month-old senescence-accelerated mouse strain P8 (SAMP8) mice were divided into three groups (n = 7): the C (control), S (sham-operated), and TL (tooth loss) groups. The Morris water maze (MWM) test was performed to assess spatial memory. Additionally, histopathological and molecular assessments of hippocampal tissues were performed. RESULTS: The TL groups exhibited impaired spatial memory in the water maze. Tooth loss induced higher protein expression levels of the neuroinflammation cytokine interleukin-1ß (IL-1ß) in the hippocampus than in the S and C groups. Tooth loss activated the NLRP3 inflammasome and increased the expression of Caspase-1 in the hippocampus. CONCLUSIONS: The findings indicated that tooth loss impairs cognitive function in SAMP8 mice and is closely related to the activation of NLRP3/Caspase-1 in the hippocampus.

Prognosis Prediction of Lung Adenocarcinoma Patients Based on Molecular Subgroups of DNA Methylation.

Lung adenocarcinoma (LUAD) is a malignant tumor with high mortality. At present, the clinicopathologic feature is the main breakthrough to assess the prognosis of LUAD patients. However, in most cases, the results are less than satisfactory. Cox regression analysis was conducted in this study to obtain methylation sites with significant prognostic relevance based on mRNA expression, DNA methylation data, and clinical data of LUAD from The Cancer Genome Atlas Program database. LUAD patients were grouped into 4 subtypes according to different methylation levels using K-means consensus cluster analysis. By survival analysis, patients were grouped into high-methylation and low-methylation groups. Later, 895 differentially expressed genes (DEGs) were obtained. Eight optimal methylation signature genes associated with prognosis were screened by Cox regression analysis, and a risk assessment model was constructed based on these genes. Samples were then classified into high-risk and low-risk groups depending on the risk assessment model, and prognostic, predictive ability was assessed using survival and receiver operating characteristic (ROC) curves. The results showed that this risk model had a great efficacy in predicting the prognosis of patients, and it was, therefore, able to be an independent prognostic factor. At last, the enrichment analysis demonstrated that the signaling pathways, including cell cycle, homologous recombination, P53 signaling pathway, DNA replication, pentose phosphate pathway, and glycolysis gluconeogenesis were remarkably activated in the high-risk group. In general, we construct an 8-gene model based on DNA methylation molecular subtypes by a series of bioinformatics methods, which can provide new insights for predicting the prognosis of patients with LUAD.

Corrigendum: Molar loss further exacerbates 2-VO-induced cognitive impairment associated with the activation of p38MAPK/NFκB pathway.

[This corrects the article DOI: 10.3389/fnagi.2022.930016.].

Molar loss further exacerbates 2-VO-induced cognitive impairment associated with the activation of p38MAPK/NFκB pathway.

Background: Vascular dementia is characterized by reduced cognitive function due to chronic cerebral hypoperfusion and has become a significant public health challenge as the global population ages. Recent studies suggested that molar loss, a common problem among the elderly, may trigger the development of cognitive decline. Our previous study found that the molar loss affected cognitive dysfunction, and the astrocytes in the hippocampus of chronic cerebral ischemia rats were affected, but the underlying mechanism is unclear. Methods: In this study, we established the animal model of molar loss with 2-VO rats and the Morris water maze was used to test the cognitive ability of rats in each group. The damage to neurons was observed via Nissl staining, and neuronal apoptosis was analyzed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay in the hippocampus of the rats. Quantitative Real-Time PCR and immunohistochemistry and histology (IHC) were used to detect the expression of p38MAPK, NFκB, caspase 3, and iNOS in the hippocampus. The astrocytes were detected by IHC and Immunofluorescence analysis for GFAP. After 2-VO MO surgery, rats were administered DMSO or p38MAPK inhibitor (SB203580) by intrathecal injection. Results: The Morris water maze test showed that the molar loss aggravated spatial memory learning ability with chronic cerebral ischemia decreased in the rats. The neuronal damage and more apoptotic cells were observed in the hippocampus of 2-VO rats. After the molar loss, the mRNA and protein expression of iNOS, p38MAPK, NFκB, and caspase 3 were further upregulated in 2-VO rats. Molar loss upregulated GFAP expression, and the p38MAPK-positive cells were labeled with the astrocyte marker GFAP. SB203580 reduced cognitive impairment and apoptosis of hippocampal neurons in 2-VO rats following the molar loss. Conclusion: Molar loss can aggravate cognitive impairment in 2-VO rats to a certain extent. The mechanism of molar loss exacerbating the cognitive decline in 2-VO rats may be associated with the activation of the p38MAPK-NFκB-caspase 3 signaling pathway, which induces neuronal apoptosis.

Azoxystrobin induces apoptosis via PI3K/AKT and MAPK signal pathways in oral leukoplakia progression.

Background: Oral leukoplakia (OLK) is one of the oral potentially malignant disorders (OPMDs) with an increased risk of developing oral squamous cell carcinoma (OSCC). There is no ideal therapeutic drug yet. Our previous study showed azoxystrobin (AZOX) inhibited the viability of OLK cells and the incidence of mouse tongue cancer. However, its specific mechanism has not been clarified. Here, we used network pharmacology with experimental validation to investigate the roles and mechanisms of AZOX in OLK. Methods: The targets of AZOX and OLK were obtained from online databases. The overlapping genes were identified by the Jvenn database. STRING and Cytoscape software were used to construct the PPI network. GO and KEGG enrichment analyses were used to analyze the biological function. Molecular docking and CETSA were used to verify the direct binding between AZOX and its key targets. 4NQO induced mouse tongue carcinogenesis model was constructed to clarify the treatment response of AZOX in vivo. TUNEL staining was performed to detect the effect of AZOX on apoptosis in mouse OLK tissues. CCK8 assay, flow cytometry, and western blot were used to detect the effect of AZOX on cell proliferation and apoptosis in DOK cells. The expression of PI3K/AKT and MAPK markers were analyzed by immunohistochemistry in vivo or by western blot in vitro. Results: Venn diagram showed 457 overlapping targets, which were involved in the PI3K/AKT, MAPK, and apoptosis pathways, and the top 5 hub modules were TP53, STAT3, AKT1, MAPK1, and PIK3R1. AZOX was bound with the highest force to AKT and PI3K by AutoDock Vina. PyMOL software visualized that AZOX could fit in the binding pocket of the AKT and PI3K. The carcinogenesis rate of the mouse OLK in the high-dose AZOX group was significantly reduced. AZOX induced apoptosis in the OLK tissues and DOK cells, and the expression of PI3K, AKT, p-ERK was decreased, and the expression of p-p38 and p-JNK was increased. CETSA indicated that AZOX might have a direct binding with AKT and PI3K. Conclusion: AZOX may induce apoptosis via PI3K/AKT and MAPK pathways in OLK. This study reveals the potential therapeutic targets of AZOX in OLK.

C1QTNF6 Targeted by MiR-184 Regulates the Proliferation, Migration, and Invasion of Lung Adenocarcinoma Cells.

OBJECTIVE: To seek out the mechanism by which C1QTNF6 mediates lung adenocarcinoma (LUAD). METHODS: Differentially expressed mRNAs and miRNAs in LUAD were analyzed using bioinformatics. In LUAD cells, C1QTNF6 mRNA and miR-184 expression were evaluated with qRT-PCR, and C1QTNF6 protein level was assessed by western blot. Cellular behaviors were assessed by colony formation, CCK-8, Transwell, and wound healing methods. The binding ability of miR-184 to C1QTNF6 was observed by dual-luciferase assay. RESULTS: High expression of C1QTNF6 in LUAD stimulated cancer cellular behaviors. MiR-184 was lowly expressed in LUAD and downregulated C1QTNF6 expression. MiR-184 restrained LUAD cell processes by targeting C1QTNF6. CONCLUSION: MiR-184 repressed LUAD cell processes via mediating C1QTNF6. MiR-184 and C1QTNF6 are expected to be indicators for LUAD treatment.

Exploring the Workplace Bullying of Indonesian Caregivers and Its Influencing Factors in Taiwan.

Background: Bullying can pose a risk to the health and safety of humans, including the risk of damage to the emotional, psychosocial, mental, or physical health of employees in the workplace. In this study, we aimed to understand the personal characteristics, mental health, sleep quality, and workplace bullying status of Indonesian caregivers and explore the influencing factors of workplace bullying among them. Methods: This cross-sectional study was based on a structured questionnaire in Indonesian, which was designed to collect the data of essential personal characteristics, workplace bullying, sleep quality, and mental health using the Indonesian versions of the Negative Acts Questionnaire−Revised (NAQ-R), Pittsburgh Sleep Quality Index (PSQI), and the Brief Symptoms Rating Scale (BSRS-5). Results: A total of 60.9% of Indonesian caregivers never experienced workplace bullying in Taiwan. A multiple regression analysis revealed that being a household caregiver (ß = 0.14, p = 0.021), sleep quality (ß = 0.18, p = 0.031), and mental health (ß = 0.44, p < 0.001) were significantly correlated with the overall workplace bullying scores of the respondents and revealed that these three variables explained 45% of the variance. Conclusions: Taiwan Indonesian caregivers have a similar workplace bullying rate to Indonesian employees in the workplace. This study indicated the relationships among the workplace bullying of foreign caregivers and demonstrated that being a household caregiver, sleep quality, and mental health were closely related.

Antibacterial, wearable, transparent tannic acid-thioctic acid-phytic acid hydrogel for adhesive bandages.

Making a hydrogel-based first-aid bandage with green resources, desirable biocompatibility, universal adhesive properties, low cost and simple production is a long-standing research aspiration. Considering this, three naturally existing organic acids, namely tannic acid, thioctic acid and phytic acid, were used to construct a novel adhesive gel (TATAPA hydrogel) for epidermal tissue bandage applications. This hydrogel could be synthesized under mild conditions with no need for a freeze-thawing shaping procedure, and was transparent, moldable and stretchable with good stability under continuous water immersion. In lap-shear tests, the TATAPA hydrogel could adhere to various hydrophilic and hydrophobic surfaces. Moreover, in the case of skin tissue adhesion, the hydrogel could be easily peeled off from the skin, meeting wearability requirements. Rheological tests showed that the hydrogel possessed thermal sensitive properties derived from multi-supramolecular interactions. The methicillin-resistant Staphylococcus aureus (MRSA)-infected burn wound test demonstrated that the hydrogel had desirable antibacterial activity and was beneficial for wound healing. A femoral artery bleeding assay was also used to reveal that the TATAPA hydrogel could be directly pasted onto the bleeding site for hemostasis. Overall, this hydrogel demonstrates potential as a surgical bioadhesive for a broad range of medical applications.

MicroRNA-9-5p Facilitates Lung Adenocarcinoma Cell Malignant Progression via Targeting STARD13.

We aimed to elucidate binding of microRNA-9-5p and STARD13 in lung adenocarcinoma (LUAD) cells and discuss their impact on malignant progression of LUAD, so as to provide evidence for identifying new therapeutic targets for LUAD. Bioinformatics analysis was introduced for analysis of differentially expressed miRNAs in LUAD tissue, and potential downstream target gene was predicted with TargetScan and other databases. MicroRNA-9-5p and STARD13 mRNA levels at cellular level was analyzed with qRT-PCR assay. Lipofectamine 2000 was applied for cell transfection. Proliferation, migration and invasion of LUAD cells were assayed with CCK-8, wound healing and Transwell assays, respectively. Protein expression of STARD13 was assessed with western blot. Binding of microRNA-9-5p and STARD13 was identified with dual-luciferase assay. Compared with normal human bronchial cells, microRNA-9-5p level in LUAD cells was noticeably increased, and STARD13 level was noticeably decreased. MicroRNA-9-5p could significantly promote malignant progression of LUAD cells, while forced STARD13 level markedly repress malignant progression of LUAD cells. Dual-luciferase gene assay showed that microRNA-9-5p had a direct targeting relationship with STARD13, and it was also found that microRNA-9-5p enhanced malignant behaviors of LUAD cells through modulating STARD13. STARD13 was a target of microRNA-9-5p in LUAD. MicroRNA-9-5p fostered malignant behaviors of LUAD cells by targeting STARD13. Therefore, microRNA-9-5p may become a new target for LUAD, and microRNA-9-5p inhibition may be a new treatment method.

Establishment and Validation of a Comprehensive Prognostic Model for Patients With HNSCC Metastasis.

OBJECTIVE: To identify biomarkers related to head and neck squamous cell carcinoma (HNSCC) metastasis and establish a prognostic model for patients with HNSCC. METHODS: HNSCC mRNA expression data of metastasis and non-metastatic samples were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. After screening the differentially expressed genes (DEGs) in the two datasets, a prognostic model, including clinical factors and biomarkers, was established, and verified in 36 samples of HNSCC by quantitative real-time transcription (qRT)-PCR. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene sets enrichment analysis (GSEA) were consulted to explore the functions of the DEGs. RESULTS: In total, 108 DEGs were identified. GSEA, GO, and KEGG analyses showed that these DEGs were mainly involved in the proliferation and metastasis of HNSCC. Six genes that were significantly related to metastasis, immune cell infiltration and prognosis were further identified to construct a prognostic gene signature. The reliability of the gene signature was verified in 36 samples of HNSCC. A prognostic model, including tumor stage, risk level, and a nomogram for prediction were further established. Receiver operating characteristic (ROC) analysis, decision curve analysis (DCA), C-index, and calibration plots showed that the model and nomogram perform well. CONCLUSION: We constructed a six-gene signature and a nomogram with high performance in predicting the prognosis of patients with HNSCC metastasis.

Assessment of Potential Prognostic Value of Peroxiredoxin 1 in Oral Squamous Cell Carcinoma.

PURPOSE: The role of the peroxiredoxin (PRDX) family in oral squamous cell carcinoma (OSCC) remains unclear. This study aimed to investigate the expression of PRDXs and their effects on the prognosis in OSCC. METHODS: The expression of PRDXs and their effects on prognosis were analysed in 216 OSCC samples from The Cancer Genome Atlas (TCGA) database. OSCC tissues and adjacent noncancerous tissues (ANTs) were obtained from 68 clinical patients. Quantitative real-time (qRT)-PCR, Western blot, and immunohistochemical (IHC) staining were used to verify the relationship between the expression level of PRDX1 and different clinical features. Gene set enrichment analysis (GSEA) was used to examine the molecular mechanism of PRDX1 in OSCC. RESULTS: PRDX1 was found to be the only gene in PRDX family that highly expressed in OSCC samples and affected the prognosis of patients with OSCC. PRDX1 expression was significantly related to tumor stage, lymphatic metastasis, and pathological grade. A nomogram consisting of tumor stage, N stage, and PRDX1 level was constructed. GSEA showed that high expression of PRDX1 involved many cancer-related molecular functions and signaling pathways. CONCLUSION: PRDX1 may play an important role in the occurrence and development of OSCC, and may be a potential new target for OSCC treatment.

miR-223-5p Suppresses OTX1 to Mediate Malignant Progression of Lung Squamous Cell Carcinoma Cells.

BACKGROUND: Lung squamous cell carcinoma (LUSC) features high morbidity and mortality as a worldwide malignant tumor. This study mainly explored a miR-223-5p-dependent mechanism that affected proliferation, invasion, and migration of LUSC cells. METHODS: Expression data of mature miRNAs and sequencing data of total RNA of LUSC were downloaded from TCGA database. Differentially expressed mRNAs were obtained. Function of miR-223-5p in LUSC cells was detected by assays like qRT-PCR, MTT, wound healing assay, Western blot, and Transwell assay. Western blot was performed to analyze the relationship between OTX1 and JAK/STAT signaling pathways. Dual-luciferase assay detected the relationship between miR-223-5p and OTX1. The way how miR-223-5p regulated LUSC cell biological functions via OTX1 was further explored. RESULTS: It was noted that miR-223-5p expression in LUSC tissue and cells was significantly reduced. Overexpression of miR-223-5p negatively regulated the proliferation, invasion, and migration of LUSC cells. The downstream target gene OTX1 was detected to be notably elevated in LUSC cells. A negative correlation between OTX1 and miR-223-5p was also found. As analyzed by GSEA, OTX1 was significantly enriched in the JAK/STAT signaling pathway and activated the pathway. Dual-luciferase assay demonstrated that OTX1 was a direct molecular target of miR-223-5p in LUSC cells. Rescue experiment verified that miR-223-5p regulated the malignant phenotypes of LUSC cells by pairing with OTX1. CONCLUSION: This study indicated that miR-223-5p was lowly expressed in LUSC cells. The impact of miR-223-5p on cell proliferation, invasion, and migration was realized by targeting OTX1. It is likely that miR-223-5p can be a novel target for LUSC treatment, which provides new ideas for future LUSC treatment.

Nicotine promotes the development of oral leukoplakia via regulating peroxiredoxin 1 and its binding proteins.

Tobacco can induce reactive oxygen species (ROS) production extensively in cells, which is a major risk factor for oral leukoplakia (OLK) development. Peroxiredoxin 1 (Prx1) is a key antioxidant protein, upregulated in a variety of malignant tumors. We previously found that nicotine, the main ingredient of tobacco, promotes oral carcinogenesis via regulating Prx1. The aim of the present study was to screen and identify the Prx1 interacting proteins and investigate the mechanisms of nicotine on the development of OLK. Through liquid chromatography-tandem mass spectrometry combined with bioinformatics analysis, the candidate Prx1 interacting proteins of cofilin-1 (CFL1), tropomyosin alpha-3 chain (TPM3), and serine/threonine-protein phosphatase 2A 65 kDa regulatory subunit A alpha isoform (PPP2R1A) were screened in human dysplastic oral keratinocyte cells treated with nicotine. CFL1, TPM3, and PPP2R1A were highly expressed in human OLK tissues. The expression of CFL1 increased and the expression of PPP2R1A decreased in OLK of smokers compared to that in OLK of non-smokers. Nicotine upregulated CFL1 and downregulated PPP2R1A in 4-nitro-quinoline-1-oxide (4NQO)-induced OLK tissues in mice in part dependent on Prx1. Furthermore, the in-situ interaction of CFL1, TPM3, and PPP2R1A with Prx1 were validated in human OLK tissues. Our results suggested that tobacco might promote the development of OLK via regulating Prx1 and its interacting proteins CFL1 and PPP2R1A.

Clinicopathological Significance of FOXO4 Expression and Correlation with Prx1 in Head and Neck Squamous Cell Carcinoma.

OBJECTIVE: Forkhead box O 4 (FOXO4), a key albumen in the forkhead box O (FOXOs) family, plays crucial roles as a tumor suppressor in the cancer development. In our previous study, Peroxiredoxin1 (Prx1) promoted the development of oral cancer and was predicted to bind to FOXO4. The aim of this study was to investigate the clinicopathological significance of FOXO4 expression and its potential mechanism in head and neck squamous cell carcinomas (HNSCC). METHODS: The function of FOXO4 correlation with HNSCC prognosis was analyzed via ONCOMINE, UALCAN, Human Protein Atlas, and cBioPortal. The expression of FOXO4 was detected in Prx1 silenced CaL27 and SCC9 cell lines by Western blot. FOXO4 protein expression was observed via immunohistochemistry (IHC) and the binding of Prx1 to FOXO4 measured by Duolink analysis in a 4-nitro-quinoline-1-oxide- (4NQO-) induced tongue carcinogenesis model in Prx1+/+ and Prx1+/- mice. RESULTS: By the analysis of Bioinformation Databases, there was a significant interaction of FOXO4 down expression to clinical tumor stages and pathological grades in the patients with HNSCC. Reduced mRNA and protein expression of FOXO4 were found to be significantly correlated with the poor overall survival (OS) of HNSCC patients. FOXO4 expression is negatively related to Prx1 significantly in HNSCC tissues. By employing a 4NQO-induced oral carcinogenesis mouse model, we confirmed that FOXO4 expression was reduced in 4NQO-induced squamous cell carcinoma (SCC) tongue tissues compared with those in normal tissues. Prx1 knockdown resulted in the upregulation of FOXO4 expression in the SCC tissues and CaL27 and SCC9 cell lines. Furthermore, the interaction of Prx1 with FOXO4 was observed in mouse tongue tissues by Duolink analysis. CONCLUSION: FOXO4 plays an important role in the development of HNSCC. The lower expression of FOXO4 is significantly correlated with the shorter OS in patients with HNSCC. FOXO4 is negatively regulated via interaction with Prx1. FOXO4 could be a potential molecular target for the treatment and prognosis of HNSCC.