Effects of single unilaterally impacted mesiodens on maxillary central incisors: A 3D quantitative assessment based on cone-beam computed tomography.

BACKGROUND: Mesiodens usually lead to the malposition and abnormal morphology of maxillary central incisors. AIM: To evaluate the detrimental effects of single unilaterally impacted mesiodens on the three-dimensional positions and morphology of the maxillary central incisor using cone-beam computed tomographic (CBCT) examinations. DESIGN: A total of 321 patients aged 5-17 years with single unilaterally impacted mesiodens were included and divided into two groups: mixed dentition group (5-10 years) and early permanent dentition group (11-17 years). CBCT data for these patients were retrospectively analyzed to compare the inclination, rotation, angulation, and morphology of maxillary central incisors between the affected and contralateral control sides. The morphology, orientation, and spatial location of mesiodens were also assessed. RESULTS: Central incisors on the affected side showed significant palatal crown inclination, shorter root, shorter tooth, and greater crown-to-root ratio in both groups, whereas significant mesial crown angulation was only observed in the mixed dentition group. CONCLUSION: Impacted mesiodentes result in the displacement and impaired root development of central incisors, strongly suggesting timely clinical management of these abnormal teeth, such as the early removal of mesiodens and orthodontic treatments.

Fully automated deep learning model for detecting proximity of mandibular third molar root to inferior alveolar canal using panoramic radiographs.

OBJECTIVE: This study endeavored to develop a novel, fully automated deep-learning model to determine the topographic relationship between mandibular third molar (MM3) roots and the inferior alveolar canal (IAC) using panoramic radiographs (PRs). STUDY DESIGN: A total of 1570 eligible subjects with MM3s who had paired PR and cone beam computed tomography (CBCT) from January 2019 to December 2020 were retrospectively collected and randomly grouped into training (80%), validation (10%), and testing (10%) cohorts. The spatial relationship of MM3/IAC was assessed by CBCT and set as the ground truth. MM3-IACnet, a modified deep learning network based on YOLOv5 (You only look once), was trained to detect MM3/IAC proximity using PR. Its diagnostic performance was further compared with dentists, AlexNet, GoogleNet, VGG-16, ResNet-50, and YOLOv5 in another independent cohort with 100 high-risk MM3 defined as root overlapping with IAC on PR. RESULTS: The MM3-IACnet performed best in predicting the MM3/IAC proximity, as evidenced by the highest accuracy (0.885), precision (0.899), area under the curve value (0.95), and minimal time-spending compared with other models. Moreover, our MM3-IACnet outperformed other models in MM3/IAC risk prediction in high-risk cases. CONCLUSION: MM3-IACnet model can assist clinicians in MM3s risk assessment and treatment planning by detecting MM3/IAC topographic relationship using PR.

The top 100 highly cited articles on surgery-first orthognathic surgery between 2009 and 2022: a bibliometric and visualized analysis.

OBJECTIVES: To reveal research focuses on surgery-first orthognathic surgery by a bibliometric and visualized analysis of the top 100 highly cited articles. STUDY DESIGN: Published papers related to surgery-first orthognathic surgery were retrospectively retrieved from the Web of Science Core Collection from 2009 to 2022. The number of articles, journals, countries/regions, institutions, authors, and keywords were assessed and visualized using CiteSpace software. RESULTS: The top 100 cited articles included 89 research papers and 11 reviews. The average total citation was 21. The most influential article with 146 citations was published by Dr. Liou E.J.W. in 2011. The most common level of evidence was level IV (36 articles). The Journal of Oral and Maxillofacial Surgery had the largest number of papers and the highest total citation frequency. The most productive countries and institutions were Korea/China and Chang Gung Memorial Hospital, respectively. Chen Yu-ray and Choi Jong Woo published 13 and 11 articles with 434 and 299 total citations, respectively. Research interests shifted from skeletal class III malocclusion, accuracy, stability, and relapse to quality of life and virtual surgical planning. CONCLUSION: Our bibliometric analyses provide a comprehensive landscape of the influential topics and developmental trends in surgery-first orthognathic surgery and inspire future studies in this booming field.

Impaired Efferocytosis Enables Apoptotic Osteoblasts to Escape Osteoimmune Surveillance During Aging.

Macrophage efferocytosis of apoptotic osteoblasts (apoOBs) is a key osteoimmune process for bone homeostasis. However, apoOBs frequently accumulate in aged bone marrow, where they may mount proinflammatory responses and progressive bone loss. The reason why apoOBs are not cleared during aging remains unclear. In this study, it is demonstrated that aged apoOBs upregulate the immune checkpoint molecule CD47, which is controlled by SIRT6-regulated transcriptional pausing, to evade clearance by macrophages. Using osteoblast- and myeloid-specific gene knockout mice, SIRT6 is further revealed to be a critical modulator for apoOBs clearance via targeting CD47-SIRPα checkpoint. Moreover, apoOBs activate SIRT6-mediated chemotaxis to recruit macrophages by releasing apoptotic vesicles. Two targeting delivery strategies are developed to enhance SIRT6 activity, resulting in rejuvenated apoOBs clearance and delayed age-related bone loss. Collectively, the findings reveal a previously unknown linkage between immune surveillance and bone homeostasis and targeting the SIRT6-regulated mechanism can be a promising therapeutic strategy for age-related bone diseases.

Development of a novel prognostic signature derived from essential genes in head and neck squamous cell carcinoma.

BACKGROUND: Substantial heterogeneity in head and neck squamous cell carcinoma (HNSCC) compromise accurate patient stratification and personalized treatment planning. Current molecular classification is largely based on genes with highly variable expression without considering their functional roles. Here, we sought to identify HNSCC essential genes for patient stratification and prognostication. METHODS: Essential genes for HNSCC were screened from genome-wide CRISPR knockout datasets. Candidates were further identified through univariate Cox regression. The least absolute shrinkage and selection operator was utilized to develop the prognostic signature. Candidate essential genes were exploited to classify patients into subgroups by consensus clustering. Survival outcomes, genomic alterations, signaling activities, and therapeutic vulnerabilities were compared between patient subgroups. RESULTS: Sixty-eight genes were identified as candidates and utilized to develop an 8-gene prognostic signature. Patients were segregated into two clusters with distinct survival rates across multiple cohorts based on upregulated essential genes. Cluster 2 exhibited higher TP53, CDKN2A, and NOTCH1 mutations, higher stromal activities, worse prognosis as well as and sensitivities to cell cycle inhibitors. Cluster 1 was characterized by a better prognosis and susceptibility to PI3K/AKT and MAPK inhibitors. CONCLUSION: Our study developed a novel and robust prognostic signature and classification derived from essential genes for HNSCC, which sheds new light on HNSCC precision oncology.

Characterizations of three-dimensional root morphology and topological location of mandibular third molars by cone-beam computed tomography.

PURPOSE: This study aimed to delineate three-dimensional (3D) root morphology and topological locations of mandibular third molars (MTMs) by cone-beam computed tomography (CBCT) in a Chinese adult dental population. METHODS: Adult patients with MTMs were retrospectively screened based on CBCT images at our institution between January 2018 and December 2019. Root morphology and spatial locations of these teeth were defined based on CBCT 3D images. Potential associations with epidemiological and clinical/radiological parameters were analyzed using Chi-square or Fisher exact test. Two-tailed P values less than 0.05 were considered statistically significant. RESULTS: A total number of 2680 eligible patients (male/female:0.74; 35 ± 10 years old) with 4180 MTMs were enrolled. The majority of MTMs had 2 roots 3064 (73.30%), followed by 800 (19.14%) 1 root, 302 (7.22%) 3 roots, and 14 (0.33%) 4 roots. More than half of one-rooted MTMs were convergent, followed by club-shaped and C-shaped. Among MTMs with 2 roots, 2860 (93.34%) were M-D (mesio-distal) types. Most MTMs with 3 roots were M-2D (one root in mesial, two roots in distal) types, followed by 2M-D (two roots in mesial, one root in distal) types, and B-2L (one root in buccal, two roots in lingual) types. The presence of root configurations was significantly associated with the angulation, depth, and width classification in two-rooted MTMs (P < 0.05). CONCLUSIONS: Although the morphology and spatial locations of MTMs vary greatly, our results from a large dental population reconfirm that most MTMs have two roots with mesial-distal type of spatial distribution.

SIRT6-regulated macrophage efferocytosis epigenetically controls inflammation resolution of diabetic periodontitis.

Rationale: Diabetes exacerbates the prevalence and severity of periodontitis, leading to severe periodontal destruction and ultimately tooth loss. Delayed resolution of inflammation is a major contributor to diabetic periodontitis (DP) pathogenesis, but the underlying mechanisms of this imbalanced immune homeostasis remain unclear. Methods: We collected periodontium from periodontitis with or without diabetes to confirm the dysfunctional neutrophils and macrophages in aggravated inflammatory damage and impaired inflammation resolution. Our in vitro experiments confirmed that SIRT6 inhibited macrophage efferocytosis by restraining miR-216a-5p-216b-5p-217 cluster maturation through ''non-canonical'' microprocessor complex (RNA pulldown, RIP, immunostaining, CHIP, Luciferase assays, and FISH). Moreover, we constructed m6SKO mice that underwent LIP-induced periodontitis to explore the in vitro and in vivo effect of SIRT6 on macrophage efferocytosis. Finally, antagomiR-217, a miRNA antagonism, was delivered into the periodontium to treat LIP-induced diabetic periodontitis. Results: We discovered that insufficient SIRT6 as a histone deacetylase in macrophages led to unresolved inflammation and aggravated periodontitis in both human and mouse DP with accumulated apoptotic neutrophil (AN) and higher generation of neutrophil extracellular traps. Mechanistically, we validated that macrophage underwent high glucose stimulation resulting in disturbance of the SIRT6-miR-216/217 axis that triggered impeded efferocytosis of AN through targeting the DEL-1/CD36 axis directly. Furthermore, we demonstrated the inhibitory role of SIRT6 for MIR217HG transcription and identified a non-canonical action of microprocessor that SIRT6 epigenetically hindered the splicing of the primary miR-216/217 via the complex of hnRNPA2B1, DGCR8, and Drosha. Notably, by constructing myeloid-specific deletion of SIRT6 mice and locally delivering antagomir-217 in DP models, we strengthened the in vivo effect of this axis in regulating macrophage efferocytosis and inflammation resolution in DP. Conclusions: Our findings delineated the emerging role of SIRT6 in mediating metabolic dysfunction-associated inflammation, and therapeutically targeting this regulatory axis might be a promising strategy for treating diabetes-associated inflammatory diseases.

The functions, oncogenic roles, and clinical significance of circular RNAs in renal cell carcinoma.

Renal cell carcinoma (RCC) is the most common form of malignancy affecting the kidneys. Circular RNAs (circRNAs) are non-coding RNAs that are derived from exonic or intronic sequences through a selective shearing process. There is growing evidence that these circRNAs can influence a range of biological pathways by serving as protein decoys, microRNA sponges, regulators of transcriptional activity, or templates for protein translation. The dysregulation of circRNA expression patterns is a hallmark of RCC and other cancer types, and there is strong evidence that these RNA species can play central roles in the onset and progression of RCC tumors. In the present review, we summarized recent findings on the functional roles and clinical impacts of circRNAs in RCC. Further, we discussed their potential utility as diagnostic biomarkers or targets for therapeutic intervention.

Comprehensive characterization of epidemiological and 3D radiographic features of non-third molar impacted teeth in a Chinese dental population.

OBJECTIVE: This retrospective study aimed to comprehensively delineate the epidemiological and 3-dimensional radiographic characteristics of non-third molar (non-M3) impacted teeth in a Chinese dental population. MATERIAL AND METHODS: Patients with impacted teeth except for the third molar (ITEM3) were retrospectively screened via cone-beam CT images from 75,021 patients treated at our institution from June 2012 to December 2018. Demographic and clinical data of patients with ITEM3 were retrieved from medical records. CBCT coupled with 3-dimensional reconstruction was employed to characterize the radiographic features of ITEM3. Associations between these epidemiological, clinical, and radiographic features were further statistically analyzed. RESULTS: Among 1975 eligible patients, 2467 ITEM3s were identified with a prevalence of 2.63% (1975/75,021). Females slightly outnumbered males with a ratio of 1.12:1. The majority of ITEM3 was single (1577, 79.85%) in the maxilla. The maxillary canine teeth were the most frequently impacted (52.45%), followed by maxillary incisors. The mesioangular position was the most common orientation (43.8%), followed by vertical and buccal-lingual orientations. The most frequently associated lesion was external root resorption of the adjacent tooth, which was significantly correlated with the morphology and position of the impacted tooth. CONCLUSION: Most ITEM3 was single, mesioangular, found at maxillary canines, sometimes associated with diverse complications. Our data advance the current understanding of ITEM3 and offer insights into the management of this dental abnormality. CLINICAL RELEVANCE: These findings are useful for clinicians to comprehensively understand the prevalence, radiographic features, and complications of non-M3 impacted teeth.

Comprehensive characterization of pleomorphic adenoma at intraoral unusual sites.

OBJECTIVE: The present study aimed to comprehensively characterize the epidemiologic characteristics, clinicopathologic characteristics, clinical treatments, and prognoses of pleomorphic adenoma (PA) identified at unusual intraoral sites. STUDY DESIGN: Patients diagnosed with PA in oral and maxillofacial regions at our institution in the past 16 years (2005-2020) were screened from the inpatient disease registry. All data concerning patients with PA found at unusual intraoral sites (defined as intraoral locations except sublingual gland and palate) were retrieved. Previously published cases with adequate clinicopathologic data were collected from PubMed and Embase. Eligible cases were further reviewed and included for statistical analyses. RESULTS: Among 1039 cases of PA diagnosed at our institution, 52 lesions were found at unusual intraoral sites. A literature review identified another 63 eligible cases from 32 articles. The upper lip was the most common sites for these lesions (n = 57), followed by buccal mucosa (n = 34), tongue (n = 8), lower lip (n = 8), and retromolar area (n = 2). Recurrence and malignant transformation after surgical resection were extremely rare for these lesions. CONCLUSIONS: PA might rarely develop at uncommon intraoral sites with atypical presentations, thus complicating its early diagnosis. Surgical resection is the major therapeutic strategy for this rare entity and has a favorable prognosis.

Epidemiological, clinical, radiographic characterization of non-syndromic supernumerary teeth in Chinese children and adolescents.

OBJECTIVE: This retrospective study was purposed to evaluate epidemiological, clinical, and 3D radiological features of supernumerary teeth (ST) in a non-syndromic Chinese children and adolescent dental population. MATERIALS AND METHODS: Original cone-beam CT (CBCT) data from 18,861 patients aged from 6 to 17 years with dental maxillofacial diseases treated in a Chinese dental hospital from June 2012 to December 2018 were utilized to screen patients with ST. Diagnosis and characterizations of ST were analyzed by CBCT coupled with 3D reconstruction. All relevant epidemiological, clinical, and radiographic details about ST were collected and statistically analyzed. RESULTS: Among total 18,861 patients, 2,768 ST were identified in 1984 subjects with a prevalence of 10.52% and a male:female ratio of 1.86:1. Majority of ST were single, conical, inverted, impacted, and located in maxilla anterior region. ST-associated complications mainly included malposition, rotation, and impaction of adjacent teeth, which were notably associated with morphology and position of ST. CONCLUSION: The prevalence of ST in Chinese children and adolescent dental population was 10.52% and tended to present as single, conical, inverted, and impacted, which resulted in abnormalities of neighboring teeth. Our outcomes are beneficial for clinicians to more comprehensively understand the incidence, characterization, and clinical treatment planning of ST in dental children and adolescents.

Restoration of TET2 deficiency inhibits tumor growth in head neck squamous cell carcinoma.

BACKGROUND: Tet methylcytosine dioxygenase 2 (TET2) has been increasingly recognized as an important tumor suppressor involved in tumorigenesis. Here, we aimed to explore the expression pattern of TET2, its clinical significance as well as functional roles in head neck squamous cell carcinoma (HNSCC). METHODS: Both mRNA and protein levels of TET2 in primary HNSCC samples were detected via immunohistochemistry and qRT-PCR, respectively. Correlations between TET2 expression with multiple clinicopathological parameters and patient survival were determined. The biological roles of TET2 in HNSCC were assessed via a gain-of-function approach and in 4-nitroquinoline-1-oxide (4NQO)-induced HNSCC model. Restoration of TET2 by chemicals including 5-Aza-2'-deoxycytidine (5-AZA), metformin or Vitamin C (VC) to inhibit tumor growth was determined in vitro and in a xenograft animal model. RESULTS: Reduced TET2 expression was found in a large fraction of HNSCC samples. Downregulated TET2 significantly correlated with larger tumor size, advanced clinical stage and inferior prognosis. Reduced TET2 and 5-hydroxymethylcytosine (5hmC) were observed along with disease progression in the 4NQO-induced HNSCC model. Enforced TET2 overexpression significantly inhibited cell proliferation, migration and enhanced the chemosensitivity of cisplatin in HNSCC cells. Restoration of TET2 following 5-AZA, metformin or VC exposure impaired cell proliferation and migration in vitro. Moreover, VC alone or in synergistic with cisplatin potently inhibited tumor growth in vivo. CONCLUSIONS: Our data reveal that reduced TET2 associates with tumor aggressiveness and reduced survival in HNSCC. Genetic or pharmacological restoration of TET2 might be a viable therapeutic strategy for HNSCC patients with TET2 deficiency.

Epidemiological, clinical, and 3-dimentional CBCT radiographic characterizations of supernumerary teeth in a non-syndromic adult population: a single-institutional study from 60,104 Chinese subjects.

OBJECTIVE: This study was aimed to delineate the prevalence, clinical, and 3-dimentional radiographic characteristics of adult supernumerary teeth (ST found) in a Chinese non-syndromic, dental population. MATERIALS AND METHODS: Medical records and cone beam computed tomography (CBCT) images were utilized to identify adult patients with ST in a tertiary referral dental hospital between June 2012 and December 2018. CBCT scan coupled with 3-dimentional reconstruction was used to characterize the detailed location, morphology, orientation of ST, and their relationship with adjacent teeth and neighboring structures. All relevant information regarding age and gender of patients, morphology, and 3-dimentional topography of ST as well as ST-associated complications were recorded and statistically analyzed. RESULTS: A total number of 1149 ST was identified in 921 eligible patients screened from 60,104 subjects with the prevalence of 1.5%. Male patients outnumbered females with a gender ratio of 1.76:1. The majority of ST was single, located in the maxilla, especially the maxillary central incisor region. Most ST were conical shape, inverted orientation, and impacted. ST-associated complications including impaction or root resorption of adjacent teeth, and cystic/tumor-like lesions were totally found in 13% ST and significantly associated with location, orientation, and morphology of ST. CONCLUSIONS: Most ST in Chinese adults were conical, inverted, impacted, and located in the maxillary central incisor region, and associated with various complications. Our findings offer valuable information concerning the prevalence, clinical, and radiographic characteristics of ST in non-syndromic Chinese adults. CLINICAL RELEVANCE: These findings are beneficial for clinicians to comprehensively understand the incidence, pathogenesis, and clinical management of ST.

Facial soft tissue thickness in Yangtze River delta Han population: Accurate assessment and comparative analysis utilizing Cone-Beam CT.

Facial approximation plays a vital role in personal identification when other methods cannot be applied, and the study on facial soft tissue thickness (FSTT) is important to allow more accurate facial approximation. The Cone-Beam CT (CBCT) is considered to be an accurate approach in assessing FSTT, however only few studies have assessed the FSTT norms by CBCT in Chinese populations. The aim of this study was to (1) establish forensic measurement approach on a 3D model reconstructed by CBCT image; (2) obtain FSTT norms from the adults of Yangtze River delta Han population; (3) determine the impacts of sex, age, BMI as well as malocclusion type on FSTT and (4) form a FSTT database through CBCT. A total of 60 facial landmarks were primarily established from 3D reconstructed models from CBCT images of 424 healthy Han adults (130 males and 294 females) aged from 21 to 50 years in Yangtze River delta region and measurements were carried out. The multivariate analysis of variance test and multiple linear regressions test showed that the FSTT values on most landmarks were significantly different between sexes and BMI, and males showed greater values, expect for the landmarks distributed in malarzygomatic areas. Simultaneously, BMI mostly affected the landmarks located in zygomatic region. Besides, only a few landmarks were influenced by age. Interestingly, several periodontal landmarks were influenced by malocclusion types, thus the impact of malocclusion types on FSTT requires attention. Finally, the validation analysis suggested that measurement approach is an important factor for FSTT.

Predictive value of prognostic nutritional index in patients with oral squamous cell carcinoma.

OBJECTIVES: To determine the prognostic significance of preoperative prognostic nutritional index (PNI) in patients with primary oral squamous cell carcinoma (OSCC) after ablative surgery. MATERIALS AND METHODS: A total of 333 patients from two tertiary referral centers were enrolled as training and validation cohorts. The PNI was calculated as 10× serum albumin (g/dL) + 0.005 × total lymphocyte number (per mm3 ), and its optimal cutoff value for patient stratification was identified by X-tile software. Cox's proportional regression analyses and receiver operating characteristic (ROC) curves were employed to identify prognostic factors and their predictive performance. RESULTS: The optimal cutoff value of PNI was 47.4. Patients with low PNI had significantly shorter overall (OS) and disease-free survival than those with high PNI. Moreover, multivariate regression analyses indicated that PNI was an independent prognostic factor for OS in the training (hazard ratio [HR], 2.267; 95% confidence interval [CI]:1.335-3.849; p = .002) and validation (HR, 2.247; 95% CI: 1.352-3.735; p = .002) cohorts. ROC analyses revealed similar or superior predictive performance of PNI as compared to other prognostic parameters. CONCLUSIONS: Our findings reveal that decreased preoperative PNI significantly associates with worse prognosis for patients with OSCC, which serves as a novel prognostic biomarker for OSCC.

Identification of a Transcriptional Prognostic Signature From Five Metabolic Pathways in Oral Squamous Cell Carcinoma.

Dysregulated metabolic pathways have been appreciated to be intimately associated with tumorigenesis and patient prognosis. Here, we sought to develop a novel prognostic signature based on metabolic pathways in patients with primary oral squamous cell carcinoma (OSCC). The original RNA-seq data of OSCC from The Cancer Genome Atlas (TCGA) project and Gene Expression Omnibus (GEO) database were transformed into a metabolic pathway enrichment score matrix by single-sample gene set enrichment analysis (ssGSEA). A novel prognostic signature based on metabolic pathways was constructed by LASSO and stepwise Cox regression analysis in the training cohort and validated in both testing and validation cohorts. The optimal cut-off value was obtained using the Youden index by receiver operating characteristic (ROC) curve. The overall survival curves were plotted by the Kaplan-Meier method. A time-dependent ROC curve analysis with 1, 3, 5 years as the defining point was performed to evaluate the predictive value of this prognostic signature. A 5-metabolic pathways prognostic signature (5MPS) for OSCC was constructed which stratified patients into subgroups with favorable or inferior survival. It served as an independent prognostic factor for patient survival and had a satisfactory predictive performance for OSCC. Our results developed a novel prognostic signature based on dysregulated metabolic pathways in OSCC and provided support for aberrant metabolism underlying OSCC tumorigenesis.

Therapeutically targeting head and neck squamous cell carcinoma through synergistic inhibition of LSD1 and JMJD3 by TCP and GSK-J1.

BACKGROUND: The histone demethylase LSD1 is a key mediator driving tumorigenesis, which holds potential as a promising therapeutic target. However, treatment with LSD1 inhibitors alone failed to result in complete cancer regression. METHODS: The synergistic effects of TCP (a LSD1 inhibitor) and GSK-J1 (a JMJD3 inhibitor) against HNSCC were determined in vitro and in preclinical animal models. Genes modulated by chemical agents or siRNAs in HNSCC cells were identified by RNA-seq and further functionally interrogated by bioinformatics approach. Integrative siRNA-mediated gene knockdown, rescue experiment and ChIP-qPCR assays were utilised to characterise the mediators underlying the therapeutic effects conferred by TCP and GSK-J1. RESULTS: Treatment with TCP and GSK-J1 impaired cell proliferation, induced apoptosis and senescence in vitro, which were largely recapitulated by simultaneous LSD1 and JMJD3 knockdown. Combinational treatment inhibited tumour growth and progression in vivo. Differentially expressed genes modulated by TCP and GSK-J1 were significantly enriched in cell proliferation, apoptosis and cancer-related pathways. SPP1 was identified as the mediator of synergy underlying the pro-apoptosis effects conferred by TCP and GSK-J1. Co-upregulation of LSD1 and JMJD3 associated with worse prognosis in patients with HNSCC. CONCLUSIONS: Our findings revealed a novel therapeutic strategy of simultaneous LSD1 and JMJD3 inhibition against HNSCC.

Identification of a prognostic alternative splicing signature in oral squamous cell carcinoma.

Alternative splicing (AS) is critically associated with tumorigenesis and patient's prognosis. Here, we systematically analyzed survival-associated AS signatures in oral squamous cell carcinoma (OSCC) and evaluated their prognostic predictive values. Survival-related AS events were identified by univariate and multivariate Cox regression analyses using OSCC data from the TCGA head neck squamous cell carcinoma data set. The Percent Spliced In calculated by SpliceSeq from 0 to 1 was used to quantify seven types of AS events. A predictive model based on AS events was constructed by least absolute shrinkage and selection operator Cox regression assay and further validated using a training-testing cohort design. Patient survival was estimated using the Kaplan-Meier method and compared with Log-rank test. The receiver operating characteristics curve area under the curves was used to evaluate the predictive abilities of these predictive models. Furthermore, gene-gene interaction networks and the splicing factors (SFs)-AS regulatory network was generated by Cytoscape. A total of 825 survival-related AS events within 719 genes were identified in OSCC samples. The integrative predictive model was better at predicting outcomes of patients as compared to those models built with the individual AS event. The predictive model based on three AS-related genes also effectively predicted patients' survival. Moreover, seven survival-related SFs were detected in OSCC including RBM4, HNRNPD, and HNRNPC, which have been linked to tumorigenesis. The SF-AS network revealed a significant correlation between survival-related AS genes and these SFs. Our findings revealed a systemic portrait of survival-associated AS events and the splicing network in OSCC, suggesting that AS events might serve as novel prognostic biomarkers and therapeutic targets for OSCC.

Combinational therapeutic targeting of BRD4 and CDK7 synergistically induces anticancer effects in head and neck squamous cell carcinoma.

The bromodomain and extra-terminal domain protein BRD4 has been recognized as a key oncogenic driver and a druggable target against cancer. However, these BRD4 inhibitors as monotherapy were moderate in efficacy in preclinical models. Here we utilized a small-scale drug synergy screen that combined the BRD4 inhibitor (JQ1) with 8 epigenetic or transcriptional targeted chemicals and identified THZ1 (a CDK7 inhibitor) acting synergistically with JQ1 against head neck squamous cell carcinoma (HNSCC). Combinational JQ1 and THZ1 treatment impaired cell proliferation, induced apoptosis and senescence, which were largely recapitulated by dual BRD4 and CDK7 knockdown. Combinational treatment inhibited tumor growth and progression in 4NQO-induced HNSCC and xenograft animal models. RNA-sequencing analyses identified hundreds of differentially expressed genes modulated by JQ1 and THZ1, which were significantly enriched in categories including cell cycle and apoptosis. Mechanistically, combinational treatment reduced H3K27ac enrichment in the super-enhancer region of YAP1, which inactivated its transcription and in turn induced anti-proliferative and pro-apoptotic effects. Combined BRD4 and CDK7 upregulation associated with worst prognosis in HNSCC patients. Collectively, our findings reveal a novel therapeutic strategy of pharmacological inhibitions of BRD4 and CDK7 against HNSCC.