The upregulation of VGF enhances the progression of oral squamous carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a prevalent neoplasm worldwide, necessitating a deeper understanding of its pathogenesis. VGF nerve growth factor inducible (VGF), a neuropeptide, plays critical roles in nerve and endocrine cell regulation.

METHODS

In this study, the TCGA datasets were initially screened, identifying the upregulation of VGF in various malignancies. We focused on OSCC cell lines, identifying the suppressor mRNA miR-432-5p as a negative regulator of VGF. Additionally, we examined the prognostic value of VGF expression in OSCC tumors and its impact on cellular functions.

RESULTS

VGF expression was found to be an independent prognostic predictor in OSCC tumors. Cells expressing VGF exhibited increased oncogenicity, influencing the proliferation and migration of oral mucosal fibroblast. Transcriptome analysis revealed associations between VGF and various pathological processes, including malignancies, exosome release, fibrosis, cell cycle disruption, and tumor immune suppression. Moreover, IL23R expression, a favorable OSCC prognostic factor, was inversely correlated with VGF expression. Exogenous IL23R expression was found to suppress VGF-associated mobility phenotypes.

CONCLUSIONS

This study highlights the multifaceted role of VGF in OSCC pathogenesis and introduces the miR-432-5p-VGF-IL23R regulatory axis as a critical mediator. The combined expression of VGF and IL23R emerges as a potent predictor of survival in oral carcinoma cases, suggesting potential implications for future therapeutic strategies.

Dental pulp cells cocultured with macrophages aggravate the inflammatory conditions stimulated by LPS

BACKGROUND

Pulp inflammation is complex interactions between different types of cells and cytokines. To mimic the interactions of different types of cells in inflamed dental pulp tissues, dental pulp cells (DPCs) were cocultured with different ratios of macrophages (THP-1) or LPS treatment.

METHODS

DPCs were cocultured with various ratios of THP-1, then photographed cell morphology and determined cell viability by MTT assay at preset times. Total RNA was also extracted to measure the inflammation marker-IL-6 and IL-8 expressions by RT-Q-PCR. The DPCs and THP-1 were treated with 0.01 - 1μg/ml lipopolysaccharide (LPS) and extract RNA at preset times, and detected IL-6 and IL-8 expression. DPCs were cocultured with various ratios of THP-1 with 0.1 μg/mL LPS, and detected IL-6 and IL-8 expression after 24 and 48 h. The data were analyzed by unpaired t-test or Mann-Whitney test. Differences were considered statistically significant when p < 0.05.

RESULTS

THP-1 and DPCs coculture models did not suppress the viability of DPCs and THP-1. Cocultured with various ratios of THP-1 could increase IL-6 and IL-8 expressions of DPCs (p = 0.0056 - p < 0.0001). The expressions of IL-6 and IL-8 were stronger in higher ratio groups (p = 0.0062 - p < 0.0001). LPS treatment also induced IL-6 and IL-8 expressions of DPCs and THP-1 (p = 0.0179 - p < 0.0001 and p = 0.0189 - p < 0.0001, separately). Under the presence of 0.1 μg/mL LPS, DPCs cocultured with THP-1 for 24 h also enhanced IL-6 and IL-8 expression (p = 0.0022). After cocultured with a higher ratio of THP-1 for 48 h, IL-6 and IL-8 expressions were even stronger in the presence of LPS (p = 0.0260).

CONCLUSIONS

Coculturing dental pulp cells and macrophages under LPS treatment aggravate the inflammatory process. The responses of our models were more severe than traditional inflamed dental models and better represented what happened in the real dental pulp. Utilizing our models to explore the repair and regeneration in endodontics will be future goals.

Cold Atmospheric Plasma Jet Irradiation Decreases the Survival and the Expression of Oncogenic miRNAs of Oral Carcinoma Cells

Despite recent advancements, therapies against advanced oral squamous cell carcinoma (OSCC) remain ineffective, resulting in unsatisfactory therapeutic outcomes. Cold atmospheric plasma (CAP) offers a promising approach in the treatment of malignant neoplasms. Although the effects of CAP in abrogating OSCC have been explored, the exact mechanisms driving CAP-induced cancer cell death and the changes in microRNA (miRNA) expression are not fully understood. We fabricated and calibrated an argon-CAP device to explore the effects of CAP irradiation on the growth and expression of oncogenic miRNAs in OSCC. The analysis revealed that, in OSCC cell lines following CAP irradiation, there was a significant reduction in viability; a downregulation of miR-21, miR-31, miR-134, miR-146a, and miR-211 expression; and an inactivation of the v-akt murine thymoma viral oncogene homolog (AKT) and extracellular signal-regulated kinase (ERK) signals. Pretreatment with blockers of apoptosis, autophagy, and ferroptosis synergistically reduced CAP-induced cell death, indicating a combined induction of variable death pathways via CAP. Combined treatments using death inhibitors and miRNA mimics, alongside the activation of AKT and ERK following the exogenous expression, counteracted the cell mortality associated with CAP. The CAP-induced downregulation of miR-21, miR-31, miR-187, and miR-211 expression was rescued through survival signaling. Additionally, CAP irradiation notably inhibited the growth of SAS OSCC cell xenografts on nude mice. The reduced expression of oncogenic miRNAs in vivo aligned with in vitro findings. In conclusion, our study provides new lines of evidence demonstrating that CAP irradiation diminishes OSCC cell viability by abrogating survival signals and oncogenic miRNA expression.

Identification of Somatic Mutations in Plasma Cell-Free DNA from Patients with Metastatic Oral Squamous Cell Carcinoma

The accurate diagnosis and treatment of oral squamous cell carcinoma (OSCC) requires an understanding of its genomic alterations. Liquid biopsies, especially cell-free DNA (cfDNA) analysis, are a minimally invasive technique used for genomic profiling. We conducted comprehensive whole-exome sequencing (WES) of 50 paired OSCC cell-free plasma with whole blood samples using multiple mutation calling pipelines and filtering criteria. Integrative Genomics Viewer (IGV) was used to validate somatic mutations. Mutation burden and mutant genes were correlated to clinico-pathological parameters. The plasma mutation burden of cfDNA was significantly associated with clinical staging and distant metastasis status. The genes TTN, PLEC, SYNE1, and USH2A were most frequently mutated in OSCC, and known driver genes, including KMT2D, LRP1B, TRRAP, and FLNA, were also significantly and frequently mutated. Additionally, the novel mutated genes CCDC168, HMCN2, STARD9, and CRAMP1 were significantly and frequently present in patients with OSCC. The mutated genes most frequently found in patients with metastatic OSCC were RORC, SLC49A3, and NUMBL. Further analysis revealed that branched-chain amino acid (BCAA) catabolism, extracellular matrix-receptor interaction, and the hypoxia-related pathway were associated with OSCC prognosis. Choline metabolism in cancer, O-glycan biosynthesis, and protein processing in the endoplasmic reticulum pathway were associated with distant metastatic status. About 20% of tumors carried at least one aberrant event in BCAA catabolism signaling that could possibly be targeted by an approved therapeutic agent. We identified molecular-level OSCC that were correlated with etiology and prognosis while defining the landscape of major altered events of the OSCC plasma genome. These findings will be useful in the design of clinical trials for targeted therapies and the stratification of patients with OSCC according to therapeutic efficacy.

The Concordant Disruption of B7/CD28 Immune Regulators Predicts the Prognosis of Oral Carcinomas

Immune modulation is a critical factor in determining the survival of patients with malignancies, including those with oral squamous cell carcinoma (OSCC) and head and neck SCC (HNSCC). Immune escape or stimulation may be driven by the B7/CD28 family and other checkpoint molecules, forming ligand-receptor complexes with immune cells in the tumor microenvironment. Since the members of B7/CD28 can functionally compensate for or counteract each other, the concomitant disruption of multiple members of B7/CD28 in OSCC or HNSCC pathogenesis remains elusive. Transcriptome analysis was performed on 54 OSCC tumors and 28 paired normal oral tissue samples. Upregulation of CD80, CD86, PD-L1, PD-L2, CD276, VTCN1, and CTLA4 and downregulation of L-ICOS in OSCC relative to the control were noted. Concordance in the expression of CD80, CD86, PD-L1, PD-L2, and L-ICOS with CD28 members was observed across tumors. Lower ICOS expression indicated a worse prognosis in late-stage tumors. Moreover, tumors harboring higher PD-L1/ICOS, PD-L2/ICOS, or CD276/ICOS expression ratios had a worse prognosis. The survival of node-positive patients was further worsened in tumors exhibiting higher ratios between PD-L1, PD-L2, or CD276 and ICOS. Alterations in T cell, macrophage, myeloid dendritic cell, and mast cell populations in tumors relative to controls were found. Decreased memory B cells, CD8⁺ T cells, and Tregs, together with increased resting NK cells and M0 macrophages, occurred in tumors with a worse prognosis. This study confirmed frequent upregulation and eminent co-disruption of B7/CD28 members in OSCC tumors. The ratio between PD-L2 and ICOS is a promising survival predictor in node-positive HNSCC patients.

Biodentine but not MTA induce DSPP expression of dental pulp cells with different severity of LPS-induced inflammation

OBJECTIVES

To explore the inflammatory and differentiation response in inflamed dental pulp cells (DPCs) induced by lipopolysaccharide (LPS) under different conditions with Biodentine and mineral trioxide aggregate (MTA) treatment.

MATERIALS AND METHODS

DPCs were treated with 0.001-1 µg/mL LPS for different periods to induce inflammation. Normal and inflamed DPCs were further treated with 0.14 mg/mL Biodentine or 0.13 mg/mL MTA for different periods. mRNA expression level of IL-6, IL-8 and ALP were analysed by qPCR. DSPP protein expression was detected by western blot. The data were analysed by the Mann-Whitney test, unpaired t test or two-way ANOVA.

RESULTS

After treatment for different times and with different concentrations of LPS, different severity of pulp inflammation was revealed by the expressions of IL-6 and IL-8. Higher concentrations of LPS induced higher IL-6 and IL-8 expressions, and these expressions first increased and then decreased (p < 0.0001). At 96 and 192 h, Biodentine significantly suppressed IL-6 expression in both normal and inflamed DPCs (p < 0.05). At 48 and 96 h, Biodentine suppressed ALP expression in both normal and inflamed DPCs (p < 0.05). At 48 and 96 h, Biodentine induced DSPP expressions in both normal and inflamed DPCs (p < 0.05).

CONCLUSION

Biodentine enhanced more DSPP differentiation of both normal and inflamed DPCs under different treatment durations than MTA.

CLINICAL RELEVANCE

The prognosis of vital pulp therapy may depend on the severity of pulp inflammation which is difficult to be determined in clinical settings. Therefore, Biodentine may enhance odontogenic differentiation in different severity of pulp inflammation imply its clinical indications.

En-face polarization-sensitive optical coherence tomography to characterize early-stage esophageal cancer and determine tumor margin

Current imaging tools are insufficiently sensitive to the early diagnosis of esophageal squamous cell carcinoma (ESCC). The application of polarization-sensitive optical coherence tomography (PS-OCT) to detect tumor-stroma interaction is an interesting issue in cancer diagnosis. In this translational study, we found that en-face PS-OCT effectively characterizes protruding, flat, and depressive type ESCC regardless of animal or human specimens. In addition, the tumor contour and margin could also be drawn and determined on a broad en-face view. The determined tumor margin could be in the proximity of 2 mm to the actual tumor margin, which was proved directly using histology.

Exploiting salivary miR-375 as a clinical biomarker of oral potentially malignant disorder

Background/purpose

Oral potentially malignant disorder (OPMD) is an important premalignancy worldwide. MicroRNAs (miRNAs) are endogenously expressed non-coding RNAs that regulate the post-transcriptional levels of targeted mRNAs. MiRNA-375 (miR-375) is markedly downregulated in oral carcinoma tissues and plays an oncogenic role in oral carcinogenesis. We explored the potential of the deregulated salivary miR-375 levels in OPMD patients.

Materials and methods

. We analyzed the levels of miR-375 in the saliva of patients with OPMD (n = 45) and healthy controls (n = 24) by quantitative RT-PCR. The cell lysates and supernatants were treated with the miR-375 mimic and inhibitor.

Results

Salivary miR-375 levels were decreased markedly in the patients with OPMD, compared with the controls. OPMD patients with non-dysplasia showed a higher abundance of miR-375 in the saliva than dysplasia patients, suggesting that salivary miR-375 is a more sensitive marker for OPMD. Patients with malignant transformation during the follow-up period showed lower expression of saliva miR-375 than the others. MiR-375 expression was markedly decreased by treatment with the miR-375 inhibitor, and the supernatants of both NHOK and SAS cells showed a corresponding decline in miR-375 expression.

Conclusion

Our results indicate the potential application of salivary miR-375 as a biomarker for the detection and long-term follow-up of OPMD.

Precise Identification of Recurrent Somatic Mutations in Oral Cancer Through Whole-Exome Sequencing Using Multiple Mutation Calling Pipelines

Understanding the genomic alterations in oral carcinogenesis remains crucial for the appropriate diagnosis and treatment of oral squamous cell carcinoma (OSCC). To unveil the mutational spectrum, in this study, we conducted whole-exome sequencing (WES), using six mutation calling pipelines and multiple filtering criteria applied to 50 paired OSCC samples. The tumor mutation burden extracted from the data set of somatic variations was significantly associated with age, tumor staging, and survival. Several genes (MUC16, MUC19, KMT2D, TTN, HERC2) with a high frequency of false positive mutations were identified. Moreover, known (TP53, FAT1, EPHA2, NOTCH1, CASP8, and PIK3CA) and novel (HYDIN, ALPK3, ASXL1, USP9X, SKOR2, CPLANE1, STARD9, and NSD2) genes have been found to be significantly and frequently mutated in OSCC. Further analysis of gene alteration status with clinical parameters revealed that canonical pathways, including clathrin-mediated endocytotic signaling, NFκB signaling, PEDF signaling, and calcium signaling were associated with OSCC prognosis. Defining a catalog of targetable genomic alterations showed that 58% of the tumors carried at least one aberrant event that may potentially be targeted by approved therapeutic agents. We found molecular OSCC subgroups which were correlated with etiology and prognosis while defining the landscape of major altered events in the coding regions of OSCC genomes. These findings provide information that will be helpful in the design of clinical trials on targeted therapies and in the stratification of patients with OSCC according to therapeutic efficacy.

miR-31-NUMB Cascade Modulates Monocarboxylate Transporters to Increase Oncogenicity and Lactate Production of Oral Carcinoma Cells

Oral squamous cell carcinoma (OSCC) is among the leading causes of cancer-associated death worldwide. miR-31 is an oncogenic miRNA in OSCC. NUMB is an adaptor protein capable of suppressing malignant transformation. Disruption of the miR-31-NUMB regulatory axis has been demonstrated in malignancies. Mitochondrial dysfunction and adaptation to glycolytic respiration are frequent events in malignancies. Monocarboxylate transporters (MCTs) function to facilitate lactate flux in highly glycolytic cells. Upregulation of MCT1 and MCT4 has been shown to be a prognostic factor of OSCC. Here, we reported that miR-31-NUMB can modulate glycolysis in OSCC. Using the CRISPR/Cas9 gene editing strategy, we identified increases in oncogenic phenotypes, MCT1 and MCT4 expression, lactate production, and glycolytic respiration in NUMB-deleted OSCC subclones. Transfection of the Numb1 or Numb4 isoform reversed the oncogenic induction elicited by NUMB deletion. This study also showed, for the first time, that NUMB4 binds MCT1 and MCT4 and that this binding increases their ubiquitination, which may decrease their abundance in cell lysates. The disruptions in oncogenicity and metabolism associated with miR-31 deletion and NUMB deletion were partially rescued by MCT1/MCT4 expression or knockdown. This study demonstrated that NUMB is a novel binding partner of MCT1 and MCT4 and that the miR-31-NUMB-MCT1/MCT4 regulatory cascade is present in oral carcinoma.

LncRNA MIR31HG Drives Oncogenicity by Inhibiting the Limb-Bud and Heart Development Gene (LBH) during Oral Carcinoma

The miR-31 host gene (MIR31HG) encodes a long non-coding RNA (LncRNA) that harbors miR-31 in its intron 2; miR-31 promotes malignant neoplastic progression. Overexpression of MIR31HG and of miR-31 occurs during oral squamous cell carcinoma (OSCC). However, the downstream effectors modulated by MIR31HG during OSCC pathogenesis remain unclear. The present study identifies up-regulation of MIR31HG expression during the potentially premalignant disorder stage of oral carcinogenesis. The potential of MIR31HG to enhance oncogenicity and to activate Wnt and FAK was identified when there was exogenous MIR31HG expression in OSCC cells. Furthermore, OSCC cell subclones with MIR31HG deleted were established using a Crispr/Cas9 strategy. RNA sequencing data obtained from cells expressing MIR31HG, cells with MIR31HG deleted and cells with miR-31 deleted identified 17 candidate genes that seem to be modulated by MIR31HG in OSCC cells. A TCGA database algorithm pinpointed MMP1, BMP2 and Limb-Bud and Heart development (LBH) as effector genes controlled by MIR31HG during OSCC. Exogenous LBH expression decreases tumor cell invasiveness, while knockdown of LBH reverses the oncogenic suppression present in MIR31HG deletion subclones. The study provides novel insights demonstrating the contribution of the MIR31HG-LBH cascade to oral carcinogenesis.

Aberrant miR-10b, miR-372, and miR-375 expression in the cytobrushed samples from oral potentially malignant disorders

Background/purpose

MicroRNA (miRNA) alterations play important roles in the neoplastic process of oral squamous cell carcinoma (OSCC). Upregulation of miR-10b and miR-372 and downregulation of miR-375 are frequent events in OSCC. The aberrances of these miRNAs in oral potentially malignant lesions (OPMD) were studied to determine their status during the establishment of OSCC.

Materials and methods

Cytobrushed sampling was used to collect epithelial cells from 11 OSCC and 34 OPMD lesions and matched normal mucosa. The expression levels of miR-10b, miR-372, and miR-375 were analyzed using quantitative reverse transcription polymerase chain reaction analysis. The clinical implications of these aberrances were further investigated.

Results

Both miR-10b and miR-372 were upregulated in OPMD, but only miR-10b expression was upregulated in OSCC comparing to control. miR-375 was downregulated in OPMD and tended to be downregulated in OSCC. Dysplastic OPMD could be distinguished based on miR-372 expression level; miR-375 expression levels facilitated discrimination between OPMD and OSCC. The combined analysis of miR-375 and miR-372 remarkably enhanced the accuracy of differentiating OPMD from OSCC.

Conclusion

Aberrant miR-10b. miR-372, and miR-375 expression occurs early during oral carcinogenesis. The detection of miR-372 and miR-375 expression using cytobrush samples may assist in differentiating between OPMD and OSCC.

The molecular functions of Biodentine and mineral trioxide aggregate in lipopolysaccharide-induced inflamed dental pulp cells

AIM

To explore the proliferation, adhesion and differentiation response and the underlying mechanisms that occur in lipopolysaccharide (LPS)-induced inflamed dental pulp cells (DPCs) in contact with Biodentine and mineral trioxide aggregate (MTA).

METHODOLOGY

The DPCs were isolated from three healthy donors and named DPC-H1 to DPC-H3. The DPCs were pre-cultured with 2 or 5 μg mL^-1 LPS for 24 h to induce inflammation. The expression of inflammation marker miR-146a was detected by q-PCR. The normal and LPS-induced DPCs were further treated with 0.14 mg mL^-1 Biodentine or 0.13 mg mL^-1 MTA for 24 h. MTT assay and adhesion assay were used to analyse the changes of cell phenotypes. DSPP, AKT and ERK expressions were detected by Western blotting. The data were analysed by Mann-Whitney test or two-way anova. Differences were considered statistically significant when P < 0.05.

RESULTS

In LPS-induced DPCs, Biodentine and MTA treatment neither induced nor aggravated LPS-induced inflammation, but their presence did increase the expression of the odontogenic differentiation marker DSPP. Under 2 or 5 μg mL^-1 LPS-induced inflammation, Biodentine and MTA promoted the proliferation of DPC cells, and significantly in DPC-H2 (P < 0.0001 for both reagents). With the treatment of 2 μg mL^-1 LPS, the cell adhesion of DPCs on the fibronectin-coated culture plates was increased significantly by Biodentine (P = 0.0413) and MTA (P < 0.0001). Biodentine and MTA regulated cell adhesion on the fibronectin-coated culture plates (P < 0.0001 for both reagents) and proliferation (P < 0.0001 for both reagents) via the AKT pathway. However, the AKT pathway was not involved in the expression of DSPP induced by Biodentine and MTA.

CONCLUSION

Biodentine and MTA enhanced the proliferation, adhesion and differentiation of LPS-induced DPCs. The proliferation and adhesion process induced by Biodentine and MTA was via the AKT pathway. However, the cellular differentiation process might not use the same pathway, and this needs to be explored in future studies.

A digital photograph study evaluating facial taperness and square face perception of Taiwanese females

BACKGROUND

This study assessed the perception of facial taperness in Taiwanese females among people with dental knowledge and laypersons. Additionally, this study also specified the criteria by which "square face" was defined regarding Taiwanese females' facial taperness.

METHODS

A series of digitally modified photos with different levels of facial taperness (Gonion to Gonion/Zygoma point to Zygoma point-Go-Go/Zy-Zy ratio ranges from 65% to 90%) were randomly arranged and presented to the raters. Visual analog scale (VAS) lines were used for scoring the photos on a scale of 0-100. The true or false question about "defining square face" was incorporated in the same questionnaire. The reliability of the true/false square face question and the esthetic evaluation by VAS were assayed. The receiver operating characteristic curve was used to define the cutoff point on "square face." The effects on the raters' genders, orthodontic treatment experience, and their professional background on the perception of a square face were assayed.

RESULTS

The overall reliability of the raters was within the acceptable range. The VAS score evaluation revealed that the average expectation for best facial taperness was 75%, whereas the facial taperness of over 83% was considered as the square face. The facial taperness reaching to 90% was regarded as the most unattractive. Gender, therapy, and professional experience have no impact on the standard of square facial form evaluation.

CONCLUSION

A face with a taperness greater than 83% was evaluated as a square face, and a face with a taperness around 75% was considered as the most attractive.

Activation of the miR-371/372/373 miRNA Cluster Enhances Oncogenicity and Drug Resistance in Oral Carcinoma Cells

Oral squamous cell carcinoma (OSCC) is among the leading causes of cancer-associated deaths worldwide. Family members in miR-371/372/373 miRNA cluster, which is localized at human chromosome 19q13.4, are co-expressed in both human stem cells and malignancies. The individual miRNA in this cluster are also involved in modulating the pathogenesis of malignancies as either oncogenes or suppressors. The 19q13 region is frequently gained in head and neck cancers. High expression of miR-372 and miR-373 are survival predictors for OSCC. However, the role of the miR-371/372/373 cluster in oral carcinogenesis remains to be fully investigated. We use the clustered, regularly interspaced, short palindromic repeats (CRISPR)-Cas9 system to establish OSCC cell subclones that had the miR-371/372/373 cluster deleted. In addition, further subclones were established that had the promoter of this cluster deleted. Concordant silencing in SAS cells of miR-371/372/373 decreased oncogenic potential, increased cisplatin sensitivity, activated p53, and upregulated the expression of Bad and DKK1. We also employed the CRISPR/dCas9 synergistic activation mediator system, which allowed robust transcriptional activation of the whole miR-371/372/373 cistron. Upregulation of endogenous miR-371/372/372 expression increased both oncogenicity and drug resistance. These were accompanied by a slight activation of AKT, β-catenin, and Src. This study identifies the oncogenic role of the miR-371/372/373 cluster in OSCC. Using CRISPR based strategy can be a powerful paradigm that will provide mechanistic insights into miRNA cluster functionality, which will also likely help the development of targeting options for malignancies.

Establishment of a p53 Null Murine Oral Carcinoma Cell Line and the Identification of Genetic Alterations Associated with This Carcinoma

Head and neck squamous cell carcinoma (HNSCC), including oral squamous cell carcinoma (OSCC), ranks sixth in cancer incidence worldwide. To generate OSCC cells lines from human or murine tumors, greatly facilitates investigations into OSCC. This study describes the establishing of a mouse palatal carcinoma cell line (designated MPC-1) from a spontaneous tumor present in a heterozygous p53 gene loss C57BL/6 mouse. A MPC-1-GFP cell subclone was then generated by lentivirus infection resulting in stable expression of green fluorescent protein. Assays indicated that MPC-1 was a p53 null polygonal cell that was positive for keratinocyte markers; it also expressed vimentin and showed a loss of E-cadherin expression. Despite that MPC-1 having strong proliferation and colony formation capabilities, the potential for anchorage independent growth and tumorigenesis was almost absent. Like other murine MOC-L and MTCQ cell line series we have previously established, MPC-1 also expresses a range of stemness markers, various oncogenic proteins, and a number of immune checkpoint proteins at high levels. However, the synergistic effects of the CDK4/6 inhibitor palbociclib on other therapeutic drugs were not observed with MPC-1. Whole exon sequencing revealed that there were high rates of non-synonymous mutations in MPC-1 affecting various genes, including Akap9, Arap2, Cdh11, Hjurp, Mroh2a, Muc4, Muc6, Sp110, and Sp140, which are similar to that the mutations present in a panel of chemical carcinogenesis-related murine tongue carcinoma cell lines. Analysis has highlighted the dis-regulation of Akap9, Cdh11, Muc4, Sp110, and Sp140 in human HNSCC as indicated by the TCGA and GEO OSCC databases. Sp140 expression has also been associated with patient survival. This study describes the establishment and characterization of the MPC-1 cell line and this new cell model should help to advance genetic research into oral cancer.

Regulatory Role of Hexokinase 2 in Modulating Head and Neck Tumorigenesis

To support great demand of cell growth, cancer cells preferentially obtain energy and biomacromolecules by glycolysis over mitochondrial oxidative phosphorylation (OxPhos). Among all glycolytic enzymes, hexokinase (HK), a rate-limiting enzyme at the first step of glycolysis to catalyze cellular glucose into glucose-6-phosphate, is herein emphasized. Four HK isoforms, HK1-HK4, were discovered in nature. It was shown that HK2 expression is enriched in many tumor cells and correlated with poorer survival rates in most neoplastic cells. HK2-mediated regulations for cell malignancy and mechanistic cues in regulating head and neck tumorigenesis, however, are not fully elucidated. Cellular malignancy index, such as cell growth, cellular motility, and treatment sensitivity, and molecular alterations were determined in HK2-deficient head and neck squamous cell carcinoma (HNSCC) cells. By using various cancer databases, HK2, but not HK1, positively correlates with HNSCC progression in a stage-dependent manner. A high HK2 expression was detected in head and neck cancerous tissues compared with their normal counterparts, both in mouse and human subjects. Loss of HK2 in HNSCC cells resulted in reduced cell (in vitro) and tumor (in vivo) growth, as well as decreased epithelial-mesenchymal transition–mediated cell movement; in contrast, HK2-deficient HNSCC cells exhibited greater sensitivity to chemotherapeutic drugs cisplatin and 5-fluorouracil but are more resistant to photodynamic therapy, indicating that HK2 expression could selectively define treatment sensitivity in HNSCC cells. At the molecular level, it was found that HK2 alteration drove metabolic reprogramming toward OxPhos and modulated oncogenic Akt and mutant TP53-mediated signals in HNSCC cells. In summary, the present study showed that HK2 suppression could lessen HNSCC oncogenicity and modulate therapeutic sensitivity, thereby being an ideal therapeutic target for HNSCCs.

Quantification of structural and microvascular changes for diagnosing early-stage oral cancer

Changes in mucosal microvascular networks, called intraepithelial papillary capillary loops (IPCL), are an important key factor for diagnosing early-stage oral cancer in vivo. Nevertheless, there are a lack of tools to quantify these changes objectively. This is the first study to quantify the IPCL changes in vivo to differentiate benign or malignant oral lesions by the optical coherence tomography (OCT) technique. K14-EGFP-miR-211-GFP transgenic mice were inducted by 4-Nitroquinoline-1-oxide to produce oral carcinogenesis in different stages, including normal, premalignancy and cancer. The results showed significant differentiation between benign or malignant lesions by OCT quantitative parameters, including epithelial thickness, IPCL density, radius and tortuosity.

The miR-372-ZBTB7A Oncogenic Axis Suppresses TRAIL-R2 Associated Drug Sensitivity in Oral Carcinoma

miR-372 has been shown a potent oncogenic miRNA in the pathogenesis of oral squamous cell carcinoma (OSCC). The zinc finger and BTB domain containing 7A protein (ZBTB7A) is a transcriptional regulator that is involved in a great diversity of physiological and oncogenic regulation. However, the modulation of ZBTB7A in OSCC remains unclear. Tissue analysis identifies a reverse correlation in expression between miR-372 and ZBTB7A in OSCC tumors. When OSCC cells have stable knockdown of ZBTB7A, their oncogenic potential and drug resistance is increased. By way of contrast, such an increase is attenuated by expression of ZBTB7A. Screening and validation confirms that ZBTB7A is able to modulate expression of the death receptors TRAIL-R1, TRAIL-R2, Fas and p53 phosphorylated at serine-15. In addition, ZBTB7A transactivates TRAIL-R2, which sensitizes cells to cisplatin-induced apoptosis. The ZBTB7A-TRAIL-R2 cascade is involved in both the extrinsic and intrinsic cisplatin-induced pathways of apoptosis. Database analysis indicates that the expression level of and the copy status of ZBTB7A and TRAIL-R2 are important survival predictors for head and neck cancers. Collectively, this study indicates the importance of the miR-372-ZBTB7A-TRAIL-R2 axis in mediating OSCC pathogenesis and in controlling OSCC drug resistance. Therefore, silencing miR-372 and/or upregulating ZBTB7A would seem to be promising strategies for enhancing the sensitivity of OSCC to cisplatin therapy.

SMAD4 Somatic Mutations in Head and Neck Carcinoma Are Associated With Tumor Progression

As the incidence and the mortality rate of head and neck squamous cell carcinoma (HNSCC) is increasing worldwide, gaining knowledge about the genomic changes which happen in the carcinogenesis of HNSCC is essential for the diagnosis and therapy of the disease. SMAD4 (DPC4) is a tumor suppressor gene. It is located at chromosome 18q21.1 and a member of the SMAD family. Which mediates the TGF-β signaling pathway, thereby controlling the growth of epithelial cells. In the study presented here, we analyzed tumor samples by multiplex PCR-based next-generation sequencing (NGS) and found deleterious mutations of SMAD4 in 4.1% of the tumors. Knock-down experiments of endogenous and exogenous SMAD4 expression demonstrated that SMAD4 is involved in the migration and invasion of HNSCC cells. Functional analysis of a missense mutation in the MH1 domain of SMAD4 may be responsible for the loss of function in suppressing tumor progression. Missense SMAD4 mutations, therefore, could be useful prognostic determinants for patients affected by HNSCCs. This report is the first study where NGS analysis based on multiplex-PCR is used to demonstrate the imminent occurrence of missense SMAD4 mutations in HNSCC cells. The gene analysis that we performed may support the identification of SMAD4 mutations as a diagnostic marker or even as a potential therapeutic target in head and neck cancer. Moreover, the analytic strategy proposed for the detection of mutations in the SMAD4 gene may be validated as a platform to assist mutation screening.

Abstract 763: The regulation of miR-125b1-peroxiredoxin like 2A anti-oxidative activity in oral squamous cell carcinoma

Head and neck cancer, including oral squamous cell carcinoma (OSCC), is the sixth most common cancer worldwide. MicroRNAs are small non-coding RNAs that are involved in the modulation of biological/pathological properties. Peroxiredoxin like 2A (PRXL2A) has been reported to be an antioxidant protein that protects cells from oxidative stress. Our previous study identified an association between PRXL2A up-regulation in OSCC and a worse patient prognosis. The miR-125 family of genes drive pluripotent regulation across a wide variety of cancers. In this study, we identify the oncogene eligibility of PRXL2A and clarify miR-125b as its upstream regulator. Down-regulation of miR-125b can be observed in OSCC tumors. Lower miR-125b expression in tumors results in a worse patient prognosis at the relatively early stage. Reporter assays were able to validate that PRXL2A is a direct target of miR-125b. Exogenous miR-125b expression in OSCC cells results in increased oxidative stress and drug sensitivity, and suppressor activity that is paralleled by the knockout of PRXL2A gene. The suppressor activity of miR-125b is able to be rescued by PRXL2A, which suggests the existence of a miR-125b-PRXL2A regulatory axis that is part of OSCC pathogenesis. Nuclear factor erythroid-2-related factor was found to be a downstream effector of the miR-125b-PRXL2A cascade. As a whole, this study has pinpointed novel clues demonstrating that down-regulation of miR-125b suppressor underlies up-regulation of PRXL2A in OSCC, and this then protects the affected tumor cells from oxidative stress resulting in a worse prognosis.

Citation Format: Yi-Fen Chen, Yun-Yen Wei, Cheng-Chieh Yang, Kuo-Wei Chang, Shu-Chun Lin. The regulation of miR-125b1-peroxiredoxin like 2A anti-oxidative activity in oral squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 763.

FAT1 somatic mutations in head and neck carcinoma are associated with tumor progression and survival

In recent years, the incidence and mortality rates of head and neck squamous cell carcinoma (HNSCC) have increased worldwide. Therefore, understanding genomic alterations in HNSCC carcinogenesis is crucial for appropriate diagnosis and therapy. Protocadherin FAT1, which encodes 4588 amino acid residues, regulates complex mechanisms to promote oncogenesis or suppression of malignancies. Multiplex PCR-based next-generation sequencing (NGS) revealed FAT1 somatic mutations. The clinicopathologic implications of FAT1 in HNSCC were investigated using expression assays, and the functional role of FAT1 in HNSCC pathogenesis was determined using ectopic expression and knockdown experiments. Approximately 29% patients with HNSCC harbored damaging FAT1 mutations. InVEx algorithm identified FAT1 as a significant functional mutation burden. Each type of mutation (missense, nonsense and frameshift) accounted for nearly one-third of deleterious mutations. FAT1 mutations correlated with lower FAT1 expression in tumors. The knockdown of the endogenous expression of FAT1 and exogenous expression of crucial FAT1 domains unequivocally indicated that FAT1 suppressed the migration and invasion capability of HNSCC cells. Functional analysis suggested that nonsense mutations in FAT1 result in the loss of the suppression of tumor progression. FAT1 mutations and downregulation defined nodal involvement, lymphovascular permeation and tumor recurrence. In addition, FAT1 mutations and downregulation are independent predictors of poor disease-free survival in patients with HNSCC. This study is the first to perform multiplex PCR-based NGS to indicate marked non-synonymous FAT1 mutations in HNSCC, which are prognostic indicators. The gene analysis strategy proposed for detecting FAT1 mutations may be a valid method for mutation screening.

Eicosanoids and HB-EGF/EGFR in cancer

Eicosanoids are bioactive lipids that play crucial roles in various pathophysiological conditions, including inflammation and cancer. They include both the COX-derived prostaglandins and the LOX-derived leukotrienes. Furthermore, the epidermal growth factor receptor (EGFR) pathways family of receptor tyrosine kinases also are known to play a central role in the tumorigenesis. Various antitumor modalities have been approved cancer treatments that target therapeutically the COX-2 and EGFR pathways; these include selective COX-2 inhibitors and EGFR monoclonal antibodies. Research has shown that the COX-2 and epidermal growth factor receptor pathways actively interact with each other in order to orchestrate carcinogenesis. This has been used to justify a targeted combinatorial approach aimed at these two pathways. Although combined therapies have been found to have a greater antitumor effect than the administration of single agent, this does not exempt them from the possible fatal cardiac effects that are associated with COX-2 inhibition. In this review, we delineate the contribution of HB-EGF, an important EGFR ligand, to the cardiac dysfunction related to decreased shedding of HB-EGF after COX-2/PGE2 inhibition. A better understanding of the molecular mechanisms underlying these cardiac side effects will make possible more effective regimens that use the dual-targeting approach.

MicroRNA miR-31 targets SIRT3 to disrupt mitochondrial activity and increase oxidative stress in oral carcinoma

MicroRNA miR-31 is implicated in the neoplastic process of various malignancies including oral squamous cell carcinoma (OSCC). Silent information regulator 3 (Sirtuin3 or SIRT3) is a NAD-dependent deacetylase that regulates metabolic process. Suppressor role of SIRT3 has been found in neoplasms. This study investigates the disruptions of miR-31-SIRT3 cascade to explore their potential association with metabolic change in OSCC. We identified that miR-31 directly targeted SIRT3 in OSCC cells, and a reverse correlation between miR-31 expression and SIRT3 expression was noted in OSCC tumors. SIRT3 expression attenuated the miR-31 enhanced tumor cell migration and invasion. It also reduced the tumorigenic potential of FaDu cell line. miR-31-SIRT3 impaired the mitochondrial membrane potential and structural integrity. The dis-regulation of this axis also contributed to the genesis of oxidative stress. In addition, miR-31 switched tumor cells from aerobic metabolism to glycolytic metabolism. This study provides novel evidences demonstrating the presence of miR-31-mediated post-transcriptional regulation of SIRT3 in OSCC. The disruption of miR-31-SIRT3 cascade and the consequential metabolic aberrances are involved in OSCC progression.

Establishing of mouse oral carcinoma cell lines derived from transgenic mice and their use as syngeneic tumorigenesis models

Background

The survival of OSCC patient needs to be further improved. miR-211 is oncogenic in OSCC and its upregulation is associated with tumor progression and poor patient survival. K14-EGFP-miR-211 transgenic mice also exhibit augmented potential for OSCC induction.

Methods

Four murine OSCC cell lines, designated MOC-L1 to MOC-L4, are established from tongue tumors induced by 4-nitroquinoline 1-oxide using the K14-EGFP-miR-211 transgenic mouse model. The genetic disruption, in vitro oncogenicity, and the eligibilities of tumorigenesis and metastasis of the cell lines are analyzed.

Results

All cell lines show green fluorescence and express a range of epithelial markers. The MOC-L1, MOC-L2 and MOC-L3 cells carry missense mutations in the DNA binding domain of the p53 gene. MOC-L1 exhibits a high level of epithelial-mesenchymal transition and has the aggressive characteristics associated with this. MOC-L1 and MOC-L2 are clonogenic in vitro as well as being tumorigenic when implanted into the dermis or tongue of syngeneic recipients. Nonetheless, only MOC-L1 exhibits immense potential for local regional and distal metastasis. Since the expression of miR-196b in MOC-L1 xenografts is drastically decreased on cisplatin treatment, it would seem that targeting of miR-196b might facilitate tumor abrogation.

Conclusions

As cell lines established in this study originated from the C57BL/6 mouse, the strain most suitable for transgenic engineering, exploring the interplay of these OSCC cells with other genetically modified cells in immune-competent mice would provide important insights into OSCC pathogenesis.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5486-7) contains supplementary material, which is available to authorized users.

IFIT1 and IFIT3 promote oral squamous cell carcinoma metastasis and contribute to the anti-tumor effect of gefitinib via enhancing p-EGFR recycling

IFIT1 and IFIT3 are abundant products of interferon-stimulating genes. While the importance of IFIT1 and IFIT3 in the prognosis of cancer has been reported, the molecular basis of IFIT1 and IFIT3 in cancer progression remains unexplored. In the present study, we investigated the modes of action and the clinical significance of IFIT1 and IFIT3 in oral squamous cell carcinoma (OSCC). Ectopic expression of IFIT1 or IFIT3 induced OSCC cell invasion by promoting the epithelial-mesenchymal transition, whereas IFIT1 or IFIT3 knockdown exhibited opposite effects. Overexpression of IFIT1 or IFIT3 promoted tumor growth, regional and distant metastasis in xenograft and orthotopic nude mice models. Most importantly, IFIT1 or IFIT3 overexpression increased the levels of p-EGFR^Y1068 and p-AKT^S473 in OSCC cells and also enhanced tumor inhibitory effect of gefitinib. By immunoprecipitation and LC-MS/MS analysis, we found that IFIT1 and IFIT3 interacted with ANXA2 that enhanced p-EGFR^Y1068 endosomal recycling. Depletion of ANXA2 using siRNA therefore abolished p-EGFR^Y1068 and p-AKT^S473 expression in IFIT1- or IFIT3-overexpressed cells. Furthermore, a significant positive association of increased IFIT1 and IFIT3 expression with advanced T-stage, lymph node metastasis, perineural invasion, lymphovascular invasion, extranodal extension, and poor overall survival rate was confirmed in OSCC patients. We also found a statistically positive correlation of p-EGFR^Y1068 expression with IFIT1 and IFIT3 in OSCC tumors and poor clinical outcome in patients. Collectively, we demonstrated a novel role of IFIT1 and IFIT3 in driving OSCC progression and metastasis by interacting with ANXA2 and hence enhancing p-EGFR recycling and its downstream signaling.

Increased Plasma Circulating Cell-Free DNA Could Be a Potential Marker for Oral Cancer

Background: Oral squamous cell carcinoma (OSCC) is a disease that affects patients worldwide. DNA of dead cells is released into the blood stream and may be isolated from plasma or serum samples. This DNA is termed cell-free DNA (cfDNA). cfDNA is increased in several types of malignancies. We investigated if there was a correlation between cfDNA levels and the progression of OSCC. Methods: Using quantitative spectrometry, we measured plasma cfDNA in 121 patients with OSCC and 50 matched controls. Mann Whitney and Wilcoxon tests were used to compare differences among various clinical variants. Receiver operating characteristic (ROC) analysis was used to obtain levels suitable for the separation of the clinical subsets. Kaplan-Meier analysis was used to assess correlation with survival. Results: Plasma cfDNA was significantly elevated in patients with OSCC relative to controls. Plasma cfDNA levels correlated with larger tumor size, cervical lymph node metastasis and late stage. Higher plasma cfDNA levels were associated with a poor prognosis of OSCC, which is a new finding. Conclusion: Plasma cfDNA could serve as a novel and easily accessible biomarker in OSCC, providing diagnostic and prognostic value.

miR-134 targets PDCD7 to reduce E-cadherin expression and enhance oral cancer progression

Oral squamous cell carcinoma (OSCC) is a common malignancy worldwide. This study clarified the oncogenic role of miR-134 in OSCC. Reporter assays, using both wild-type and mutant constructs, confirmed that Programmed Cell Death 7 (PDCD7) gene was a potential target of miR-134. The OSCC cells exogenously expressed miR-134 exhibited reduced PDCD7 expression. As expected, exogenous miRZip-134 expression increased PDCD7 expression in the OSCC cells; additionally, PDCD7 expression suppressed the oncogenicity of the OSCC cells. By contrast, PDCD7 knockout through gene editing increased in vitro oncogenicity and neck nodal metastasis in mice, and reduced E-cadherin (E-cad) expression. PDCD7 transactivated E-cad expression via the GC-box in the promoter. Moreover, miR-134-associated cellular transformation and E-cad downregulation was attenuated by PDCD7. Downregulation of both PDCD7 and E-cad and high levels miR-134 expression was observed in OSCC tumor tissues. Activation of the miR-134-PDCD7-E-cad pathogenesis cascade occurred early during the human and murine oral carcinogenesis process. In conclusion, the oncogenic effect of miR-134 in oral carcinoma is mediated by reducing PDCD7 and E-cad expression.

Abstract 4422: miR-125b mediates oral cancer suppression by targeting the antioxidative gene peroxiredoxin like 2A (PRXL2A)

Oral squamous cell carcinoma (OSCC) is a globally prevalent malignancy. The molecular mechanisms of this cancer remain to be elucidated to acquire further interception. Peroxiredoxin like 2A (PRXL2A) was named FAM213A previously, has been reported an antioxidant protein that protects cells from oxidative stress. Our previous study has identified the association between PRXL2A up-regulation in OSCC and the worse prognosis of patients. MicroRNAs (miRNAs) are small non-coding RNAs involved in the modulation of physical or pathological properties. miR-125 family genes drive pluripotent regulation in a wide variety of cancers. In this study, we specified the oncogenic eligibility of PRXL2A and clarified miR-125b as its upstream regulator. Down-regulation of miR-125b was observed in OSCC tumors. Lower miR-125b expression in OSCC tissues defined the worse patient prognosis. Reporter assays validated that PRXL2A as a direct target of miR-125b. Exogenous miR-125b expression resulted in the decreased oxidative stress, increased drug sensitivity, and suppressor activities, which was consistent with the knockout of PRXL2A gene in OSCC cells. That the suppressor activities of miR-125b being rescued by PRXL2A denoted the existence of miR-125b-PRXL2A regulatory axis in OSCC pathogenesis. Knockout of PRXL2A drastically attenuated the tumorigenic potential of OSCC cells. Overall, this study proposes novel clues demonstrating that the down-regulation of miR-125b suppressor underlies the PRXL2A up-regulation in OSCC, and this protects tumor cells from oxidative stress leading to the worse patient survival.

Citation Format: Yi-Fen Chen, Yun-Yen Wei, Cheng-Chieh Yang, Chung-Ji Liu, Kuo-Wei Chang, Shu-Chun Lin. miR-125b mediates oral cancer suppression by targeting the antioxidative gene peroxiredoxin like 2A (PRXL2A) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4422.

Abstract 479: miR-372 enhances tumorigenesis and drug resistance in oral carcinoma by targeting ZBTB7A transcription factor

miRNA-mediated post-transcriptional regulation of targeted genes plays crucial roles in neoplastic process. miR-372 has been shown an oncogenic miRNA which is hypoxia-inducible and is conspicuously up-regulated in oral squamous cell carcinoma (OSCC). Zinc finger and BTB domain containing 7A (ZBTB7A) is a transcriptional repressor modulating a great diversities of physiological or oncogenic regulation. This study identified that ZBTB7A was a direct target of miR-372. ZBTB7A was down-regulated in 75% of OSCC tumors relative to adjacent oral mucosa. Reverse correlation across miR-372 expression and ZBTB7A expression was found in tumor samples. In OSCC cells with the stable knockdown of ZBTB7A, the oncogenic potential and drug resistance increased. Whereas, such increase was attenuated by ZBTB7A expression. High throughput screening and validation assay confirmed that ZBTB7A was able to repress multiple oncogenic factors and activate the expression of Trail-R1, Trail-R2 and Fas to increase the drug sensitivity in OSCC cells. miR-372 induction drastically repressed the expression of apoptosis genes by inhibiting ZBTB7A. This was accompany with the enrichment of oncogenicity and the increased tolerance to the toxicity of cisplatin and taxol. This study signifies the importance of miR-372-ZBTB7A-downstream effectors in mediating pathogenesis and drug resistance of OSCC. Interception of this pathogenic cascade would confer therapeutic benefits against oral carcinoma.

Citation Format: Li-Yin Yeh, Chung-Hsien Chou, Chung-Ji Liu, Shu-Chun Lin, Kuo-Wei Chang. miR-372 enhances tumorigenesis and drug resistance in oral carcinoma by targeting ZBTB7A transcription factor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 479.

Abstract 5524: Tumor suppressor Numb represses monocarboxylate transporters to reduce the glycolysis in oral carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common malignancies worldwide. Our previous studies have shown that Numb pluripotent gene drives suppressor activity against OSCC, and it is co-targeted by multiple oncogenic miRNAs. In this study, we further identified that Numb mRNA expression was down-regulated in a large fraction of OSCC tumors. We established the Numb-knockout (KO) OSCC cell subclones using CRISPR-Cas9 system. We also generated lentiviruses for exogenous expression of Numb 1 and Numb 4 isoforms. The anchorage independent growth potential was found increased in Numb-KO cell subclones. However, such eligibility was repressed after the rescue of the Numb expression by lentiviral infection. In addition, the level of lactate production and the ratio of ECAR/OCR in the Numb-KO cell subclones were higher than parental cells. The knockout of Numb was able to up-regulate the expression of monocarboxylate transporter (MCT) family members MCT1 and MCT4, but not other metabolism genes, to increase the lactate production. Knockdown of both MCT1 and MCT4 significantly decreased the anchorage independent growth and the lactate production of OSCC cells. This study provides new evidences denoting that Numb represses MCTs to attenuate the transformative capability and the glycolysis in oral carcinoma.

Citation Format: Chung-Hsien Chou, Chun-Yu Fan Chaing, Shu-Chun Lin, Kuo-Wei Chang, Hsi-Feng Tu. Tumor suppressor Numb represses monocarboxylate transporters to reduce the glycolysis in oral carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5524.

Combination of structural and vascular optical coherence tomography for differentiating oral lesions of mice in different carcinogenesis stages

Differentiating between early malignancy and benign lesions in oral cavities is difficult using current optical tools. As has been shown in previous studies, microvascular changes in squamous epithelium can be regarded as a key marker for diagnosis. We propose the combination of structural and vascular optical coherence tomography (OCT) imaging for the investigation of disease related changes. Progressive thickness changes of epithelium and the destruction of underlying lamina propria was observed during cancer development in a 4- nitroquinoline-1-oxide (4NQO) mouse model. At the same time, microvascular changes in hyperplasia, dysplasia, carcinoma in situ and advanced cancer were observed. Findings from OCT imaging were compared with histology.

The correlation between HIF-1 alpha and VEGF in oral squamous cell carcinomas: Expression patterns and quantitative immunohistochemical analysis

BACKGROUND

The prognostic predict biomarkers are important in oral squamous cell carcinoma (OSCC). We investigated the expression patterns and quantitation of hypoxia-inducible factor-1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF) in OSCC patients. Among OSCC patients with recurrence and metastasis, the expression percentages of HIF-1α and VEGF also were analyzed.

METHODS

Thirty-eight patients (8 hyperkeratosis, 30 oral squamous cell carcinoma) were included in this study. In the follow-up period, 5 OSCC patients had metastasis and 12 OSCC patients had local recurrence. We used computer-assisted image processing to analyze immunohistochemistry (IHC). The quantitative analysis of IHC slides, including upper-layer epithelium (U) and lower-layer epithelium (L), was calculated.

RESULTS

We found homogeneous expression of VEGF in the epithelium. However, two patterns of HIF-1α expression were observed: homogeneous and heterogeneous. The highest U + L layer percentage in HIF-1α and VEF expression had significant association in tumor metastasis and recurrence (p<0.001 in HIF-1α and p<0.001 in VEGF). U + L layer HIF-1α expression percentage was >156.4%, and the survival rate was poor (p < 0.001).

CONCLUSION

HIF-1α expression was not only influenced by tumor hypoxia, it also reflected tumor cell characteristics. High concentrations of VEGF and HIF-1α may have value as prognostic markers of tumor metastasis and recurrence.

Targeting of miR-31/96/182 to the Numb gene during head and neck oncogenesis

BACKGROUND

MicroRNAs (miRNAs) play crucial roles in head and neck squamous cell carcinoma (HNSCC). This study investigates whether miR-31, miR-96, and miR-182 are involved in targeting Numb during HNSCC.

METHODS

The expression of miR-31/96/182 in tumor tissues was analyzed. Reporter assay, knockdown, expression, and oncogenic analysis were carried out in cell lines.

RESULTS

Upregulation of miR-31/96/182 was detected in tumor tissues. In addition, advanced tumors showed higher expression levels of these miRNAs. The expression of these miRNAs was upregulated after treatment with areca ingredients (P < .01 or P < .001). These miRNAs directly targeted the 3' untranslated region (UTR) sequence of the Numb gene. An increased migration and invasion of HNSCC cells was associated with the exogenous expression of miR-31/96/182 (P < .01 or P < .001), and this was reverted by expression of Numb.

CONCLUSION

This study provides new evidence demonstrating that there is frequent and concordant upregulation of miR-31, miR-96, and miR-182 during HNSCC and these miRNAs co-target Numb.

miR-31 targets ARID1A and enhances the oncogenicity and stemness of head and neck squamous cell carcinoma

miR-31 is oncogenic for head and neck squamous cell carcinoma (HNSCC). Proteins containing the AT-rich interacting domain (ARID) modulate the accessibility of chromatin to the transcription machinery needed for gene expression. In this study, we showed that miR-31 was able to target ARID1A in HNSCC. HNSCC tumors had an inverse miR-31 and ARID1A expression. miR-31 associated oncogenicities were rescued by ARID1A expression in HNSCC cells. Furthermore, ARID1A repressed the stemness properties and transcriptional activity of Nanog/OCT4/Sox2/EpCAM via the protein's affinity for AT-rich sites within promoters. HNSCC patients with tumors having high level of miR-31 expression and high levels of Nanog/OCT4/Sox2/EpCAM expression, together with low level of ARID1A expression, were found to have the worst survival. This study provides novel mechanistic clues demonstrating that miR-31 inhibits ARID1A and that this enriches the oncogenicity and stemness of HNSCC.

MicroRNA-21 promotes perineural invasion and impacts survival in patients with oral carcinoma

BACKGROUND

Perineural invasion is a pathological feature that may affect cancer cell progression and thus can result in prognostic impacts, especially in oral squamous cell carcinoma (OSCC). However, factors regulating perineural invasion during OSCC remain obscure.

METHODS

Expression of miR-21 and phosphatase and tensin homolog was checked in surgical specimens from cases of OSCC. The results were analyzed for histopathologic factors, including perineural invasion and clinical prognosis.

RESULTS

One-hundred cases of OSCC patients were enrolled in this study. High expression of miR-21 was related to perineural invasion and worse prognosis in OSCC patients.

CONCLUSION

miR-21 was an independent factor of disease survival of OSCC. miR-21/phosphatase and tensin homolog disregulation was related to perineural invasion.

Abstract 953: miR-31 targets ARID1A to enhance the progression of oral carcinoma

miR-31 is an oncogenic microRNA in several malignancies including oral squamous cell carcinoma (OSCC). However, the function of miR-31 in modulating the stem cell properties in OSCC has not yet been explored. AT-rich interacting domain (ARID) containing protein members play pluripotent roles in modulating chromatin accessibility of the transcription machineries for gene expression. ARID1A has been shown suppressive to several malignancies and the driver mutations in ARID1A gene are noted in tumors. In this study, we identified that miR-31 targets ARID1A in OSCC, and a reverse expression between miR-31 and ARID1A was noted in OSCC tumors. Furthermore, the miR-31 induced migration, invasion, CSC cell population and stemness gene expression were rescued by ARID1A expression in OSCC cells. ARID1A suppressed the transcription activity of a panel of stemness markers through its affinity to A-T rich region in the promoters. A reverse correlation between ARID1A and these stem cell markers was also seen in OSCC tumors. miR-31+/ARID1A− OSCC cell subclone exhibited higher potency in sphere formation, as well as tumorigenesis and neck metastasis in nude mice relative to other cell subclones. In addition, tumors carrying high miR-31 expression and low ARID1A expression had the worst survival. In summary, this study provides novel mechanistic clues demonstrating that miR-31 targets ARID1A to enrich the stemness properties for OSCC progression.

Citation Format: Wen-Cheng Lu, Shu-Chun Lin, Kuo-Wei Chang. miR-31 targets ARID1A to enhance the progression of oral carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 953.

Abstract 1108: MicroRNA-211 enhances the oncogenicity of oral carcinoma through targeting TCF12 and up-regulating FAM213A expression

To address the oncogenic roles of miR-211, we generated K14-EGFP-miR-211 transgenic mouse lines. Upon the 4-nitroquinoline 1-oxide (4NQO) induction, the transgenic mice exhibited more extensive and severe tumorigenesis in tongue compared to the controls. 4NQO up-regulated miR-211 expression in oral squamous cell carcinoma (OSCC) cells. miR-211 directly targeted transcription factor 12 (TCF12), which mediated suppressor activities and was drastically down-regulated in OSCC tumors. GeneChip analysis, bioinformatic algorithm, reporter assay and ChIP assay pinpointed that Family with Sequence Similarity 213, Member A (FAM213A), an anti-oxidative molecule, was transcriptionally repressed by TCF12. Knockdown of FAM213A decreased oncogenic activity and ALDH1-positive cell population, and increased oxygen stress in OSCC cells. The expression of TCF12 and FAM213A was inversely correlated in head and neck carcinoma samples according to The Cancer Genome Atlas. OSCC patients carrying tumors with high FAM213A expression tended to have worse survival. Furthermore, 4NQO treatment down-regulated TCF12 and up-regulated FAM213A through modulating miR-211. The transgenic mouse model recaptures the molecular and histopathological changes as seen in human OSCC pathogenesis. This study highlights that miR-211 responds to oncogenic stimuli to promote the neoplastic process of OSCC by targeting TCF12 and up-regulating FAM213A.

Citation Format: Yi-Fen Chen, Kuo-Wei Chang, Shu-Chun Lin. MicroRNA-211 enhances the oncogenicity of oral carcinoma through targeting TCF12 and up-regulating FAM213A expression. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1108.

MicroRNA-211 Enhances the Oncogenicity of Carcinogen-Induced Oral Carcinoma by Repressing TCF12 and Increasing Antioxidant Activity

miR-211 expression in human oral squamous cell carcinoma (OSCC) has been implicated in poor patient survival. To investigate the oncogenic roles of miR-211, we generated K14-EGFP-miR-211 transgenic mice tagged with GFP. Induction of oral carcinogenesis in transgenic mice using 4-nitroquinoline 1-oxide (4NQO) resulted in more extensive and severe tongue tumorigenesis compared with control animals. We found that 4NQO and arecoline upregulated miR-211 expression in OSCC cells. In silico and experimental evidence further revealed that miR-211 directly targeted transcription factor 12 (TCF12), which mediated suppressor activities in OSCC cells and was drastically downregulated in tumor tissues. We used GeneChip analysis and bioinformatic algorithms to identify transcriptional targets of TCF12 and confirmed through reporter and ChIP assays that family with sequence similarity 213, member A (FAM213A), a peroxiredoxin-like antioxidative protein, was repressed transcriptionally by TCF12. FAM213A silencing in OSCC cells diminished oncogenic activity, reduced the ALDH1-positive cell population, and increased reactive oxygen species. TCF12 and FAM213A expression was correlated inversely in head and neck carcinoma samples according to The Cancer Genome Atlas. OSCC patients bearing tumors with high FAM213A expression tended to have worse survival. Furthermore, 4NQO treatment downregulated TCF12 and upregulated FAM213A by modulating miR-211 both in vitro and in vivo Overall, our findings develop a mouse model that recapitulates the molecular and histopathologic alterations of human OSCC pathogenesis and highlight a new miRNA-mediated oncogenic mechanism. Cancer Res; 76(16); 4872-86. ©2016 AACR.

Up-regulation of HB-EGF by the COX-2/PGE2 signaling associates with the cisplatin resistance and tumor recurrence of advanced HNSCC

OBJECTIVES

When treating advanced HNSCC, a cisplatin-based systemic regimen benefit patient survival. However, chemoresistance will greatly reduce the effectiveness of this approach. The identification of molecules that contribute to cisplatin resistance may potentially improve the survival. Both HB-EGF and COX-2 have been reported to increase cisplatin-resistance. Here, we have focused on the regulation of HB-EGF/COX-2 and their roles in cisplatin resistance.

MATERIALS AND METHODS

IHC staining was used to measure the expression levels of HB-EGF and COX-2 on the tissue microarray from 43 tissue samples of patients with advanced HNSCC. siRNA, western blot and qRT-PCR were used to dissect the regulation between EGF, Akt, COX-2, PGE2, and cisplatin sensitivity. The correlation between HB-EGF, COX2 and HNSCC progression was analyzed by the receiver operating characteristic (ROC) curve and Kaplan-Meier disease free survival.

RESULTS

Patients of advanced HNSCC patients with increased HB-EGF and COX-2 expression have higher tumor recurrent rates that was related to cisplatin resistance. The resistance was mediated via an increased expression of HB-EGF and COX-2. The activation of Akt by either EGF or areca nut extract were able to upregulate COX-2, which would increase the expression of HB-EGF in a PGE2 dependent manner. Inhibition and knockdown of COX-2 resulted in a decrease in HB-EGF. In the tissue samples from HNSCC patients, there was a significant positive correlation between the expression of COX-2 and HB-EGF.

CONCLUSION

Our results suggested that COX-2 and HB-EGF are important in development of HNSCC cisplatin resistance. These findings may help the development of new strategies for overcoming cisplatin resistance.

miR-372 inhibits p62 in head and neck squamous cell carcinoma in vitro and in vivo

Here we showed that exogenous miR-372 expression and knockdown of p62 (sequestosome1 or SQSTM1), both increased migration of head and neck squamous cell carcinoma (HNSCC) cells. p62 induced phase II detoxification enzyme NADPH quinone oxidoreductase 1 (NQO1), which decreased ROS levels and cell migration. Also, miR-372 decreased p62 during hypoxia, thus increasing cell migration. Levels of miR-372 and p62 inversely correlated in human HNSCC tissues. Plasma levels of miR-372 was associated with advanced tumor stage and patient mortality. Both plasma and salivary miR-372 levels were decreased after tumor resection. We conclude that miR-372 decreases p62, thus increasing ROS and motility in HNSCC cells.

MicroRNA-31 upregulation predicts increased risk of progression of oral potentially malignant disorder

OBJECTIVES

MicroRNAs (miRNAs, miRs) have shown diagnostic and prognostic potential for oral cancer but their role in oral potentially malignant disorder (OPMD) has been less investigated. We aimed to assess whether miR-21 and miR-31, two of the most relevant miRNAs in oral cancer, are useful as prognostic factors for OPMD progression.

MATERIALS AND METHODS

miR-21 and miR-31 in 20 saliva samples and 46 tissue samples from patients with OPMD (mean follow-up of 820days) were analyzed by quantitative reverse transcription PCR and in situ hybridization, respectively. The log-rank test, receiver operating characteristic curve, and Kaplan-Meier disease free survival analysis were used to assess the correlation between miRNA levels and OPMD progression.

RESULTS

Significantly increased salivary miR-21 and miR-31 expression (P=0.003 and P<0.001, respectively) was observed in patients with OPMD compared to control individuals. Patients with recurrent OPMD and/or malignant transformation exhibited a further augmented expression of miR-31, but not miR-21, in the epithelium. Furthermore, increased miR-31 expression as well as epithelial dysplasia is an independent risk factor for OPMD progression as demonstrated in Cox-proportional hazard model (HR: 8.43, P<0.05, 95%CI: 1.04 to 68.03).

CONCLUSIONS

Salivary miR-21 and miR-31 are applicable as useful OPMD screening tools. Epithelial dysplasia and miR-31 up-regulation synergistically predict the increased incidence of recurrence and/or malignant transformation in patients with OPMD. Detection of miR-31 expression is an adjuvant method for screening of high-risk OPMD.

The increase of oncogenic miRNA expression in tongue carcinogenesis of a mouse model

OBJECTIVES

This study investigated the oncogenic miRNA level in the tissue and biofluids in the Nitroquinoline 1-Oxide (4NQO)-induced mouse tongue carcinogenesis model for potential diagnostic or therapeutic application.

MATERIALS AND METHODS

The histological examination, immunohistochemistry, in situ hybridization, quantitative PCR analysis and bioinformatic algorithms were performed to unravel the signaling activation and miRNA expression in female murine samples.

RESULTS

The increase of miR-21 and miR-31 staining, and EGFR activation paralleled the severity of 4NQO-induced epithelial pathogenesis in tongue epithelium. A progressive increase of miR-21, miR-31 and miR-146a in both saliva and plasma samples was also noted. miR-31 was the earliest emerging miRNA in the saliva. The increase of plasma miR-146a, miR-184 and miR-372 was detectable early in the induction, and it was particularly eminent at the most advanced lesion state. The combined analysis of the multiple oncogenic miRNAs in the plasma signified a potent discriminative capacity between normal and pathological states. As the blockage of EGFR or AKT activation drastically reverted the miR-21, miR-31 and miR-146a expression induced by 4NQO in human oral carcinoma cell lines, the results implicated a mechanistic linkage of the oncogenic miRNAs' induction through EGFR/AKT activation.

CONCLUSIONS

In this study, we show the dysregulation of oncogenic miRNAs in murine tongue tumorigenesis, which simulates human counterparts. Increased multiple miRNAs in the biofluids may be valuable non-invasive markers in detecting oral carcinogenesis at an early stage. This animal model may also be useful for developing liquid biopsies and prevention strategies against oral carcinoma by abrogating EGFR or oncogenic miRNAs.

Abstract 178: Targeting of multiple oncogenic miRNAs on NUMB gene to mediate head and neck carcinogenesis

Head and neck squamous cell carcinoma (HNSCC) is the 6th leading malignancy in the world. MicroRNAs (miRNAs) are small, non-coding RNAs, which are associated with the genesis and progression of cancers. NUMB is a multi-functional adaptor protein, which can activate E3 ubiquitin ligase and degrade target proteins to modulate pathogenesis. In silico modules predict that miR-31, miR-96, miR-182 and other miRNAs might target NUMB. This study investigates the concordant targeting of multiple oncogenic miRNAs to NUMB, and to verify the roles of NUMB in HNSCC. miR-31, miR-96 and miR-182 were found up-regulated in the vast majority of HNSCC tissues. On the contrary, NUMB expression was largely down-regulated in the tumors. A reverse correlation was noted between miR-31 expression and NUMB expression. Reporter assays using wild type and mutant constructs specified that these oncogenic miRNAs directly target the sequences in the 3′UTR of NUMB gene. However, miR-31 was unable to target a predicted site in the coding sequence of NUMB gene to mediate regulation. Exogenous expression of these miRNAs decreased NUMB expression and increased the migration of HNSCC cells. Knockdown of NUMB expression enhanced oncogenicity of HNSCC cells. However, the exogenous NUMB expression decreased the migration and anchorage-independent growth of HNSCC cells. The oncogenicity induced by these oncogenic miRNAs was attenuated by NUMB expression. This study provides in vitro and in vivo clues demonstrating that miR-31, miR-96 and miR-182 co-target NUMB gene in HNSCC. The coordinative abrogation of these miRNAs together with NUMB enhancement may be contributive to new therapeutic intervention against head and neck cancers.

Citation Format: Chung-Shan Chou, Kuo-Wei Chang, Shu-Chun Lin. Targeting of multiple oncogenic miRNAs on NUMB gene to mediate head and neck carcinogenesis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 178. doi:10.1158/1538-7445.AM2015-178

Abstract 181: miR-134 targets programmed cell death 7 (PDCD7) gene to modulate the pathogenesis of head and neck carcinoma

Head and neck squamous cell carcinoma (HNSCC) is one of the prevalent malignancies in the world. microRNAs (miRNAs) are involved in the neoplastic process of various malignancies including HNSCC to mediate post-transcriptional down-regulation of target genes. This study shows that miR-134 enhances the proliferation, migration and invasion of HNSCC cells. In silico modules predict that programmed cell death 7 (PDCD7) gene could be one of the targets of miR-134. In stable HNSCC cell subclones, ectopic miR-134 expression decreased PDCD7 expression; while the ectopic miR-134Zip expression increased PDCD7 expression. Reporter assays confirmed the binding of miR-134 to the wild type 3′UTR of PDCD7, which decreased reporter activity. The targeting of miR-134 to the 3′UTR of PDCD7 was abolished by the mutations in targeted sequences. Moreover, miR-134Zip expression increased the activity of wild type reporter. Down-regulation of PDCD7 was identified in around 70% of HNSCC tumors, which was significantly opposite to miR-134 expression. A trend of reverse expression between miR-134 and PDCD7 was also present in HNSCC cell lines. PDCD7 was up-regulated following the apoptosis induced by cis-platin. Ectopic PDCD7 expression decreased the proliferation and migration of HNSCC cells, but it was unable to affect apoptosis or drug resistance status. Moreover, miR-134 associated oncogenicity was attenuated by PDCD7 expression. Taking together, this study concludes that the oncogenic potential of miR-134 in head and neck carcinoma is able to be mediated by targeting PDCD7.

Citation Format: Shih-Yuan Peng, Kuo-Wei Chang, Shu-Chun Lin, Hsi-Feng Tu. miR-134 targets programmed cell death 7 (PDCD7) gene to modulate the pathogenesis of head and neck carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 181. doi:10.1158/1538-7445.AM2015-181

Abstract 4000: The increase of oncogenic miRNA expression in tongue carcinogenesis of a mouse model

Oral carcinoma is one of the leading causes of cancer death in the world. To develop biomarkers for early detection may bestow substantial benefits in diagnosis and the prevention of tumor progression. An animal model simulating the human pathogenesis will also be useful for developing therapeutic strategies. miRNAs are short, non-coding RNAs, which play important roles in neoplastic process. The detection of biomarkers in body fluid may enable non-invasive diagnostic approaches. This study used mouse chemical carcinogenesis model to investigate the disruption of miRNA expression in oral tongue tissues, and to explore the miRNA level in saliva and blood during pathogenesis. Mice were fed with 4-Nitroquinoline 1-Oxide (4NQO) in drinking water for 12 weeks and were kept for extended periods for tumor induction. The histological examination showed the consecutive increase in the severity of epithelial pathogenesis from hyperkeratosis, hyperplasia to epithelial dysplasia and squamous tumors following the increase of 4NQO exposure. The increase of miR-21 and miR-31 staining, as well as p53, pAKT and Ki-67 immunoreactivity parallels the severity of epithelial pathogenesis in tongue tissues. A progressive increase of multiple oncogenic miRNAs in both saliva and blood samples was also noted. The increase of miR-21, miR-31 and miR-372 in the saliva and the increase of miR-146a and miR-184 in the blood sample were particularly eminent during the field cancerization process of tongue. In addition, the dysregulation of these oncogenic miRNAs and other molecular events in this model are similar to the disruption being identified in human counterparts. As these miRNAs are functionally oncogenic, their increase in the saliva and blood of mice may be valuable biomarkers to develop diagnosis and prevention strategies against oral carcinomas.

Keywords: chemical, carcinoma, miRNA, mouse, mouth

Note: This abstract was not presented at the meeting.

Citation Format: YUYU KAO, Shu-Chun Lin, Kuo-Wei Chang. The increase of oncogenic miRNA expression in tongue carcinogenesis of a mouse model. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4000. doi:10.1158/1538-7445.AM2015-4000

Upregulation of miR-372 and -373 associates with lymph node metastasis and poor prognosis of oral carcinomas

OBJECTIVES/HYPOTHESIS

Oral squamous cell carcinoma (OSCC) is prevalent worldwide, and survival in OSCC has not improved significantly in the last few decades. MicroRNAs (miRNAs) have an important regulatory role in human cancer, including oral carcinogenesis. MiR-372 and miR-373 perform oncogenic and tumor-suppressive functions of between different human malignancies. This study investigated the miR-372 and miR-373 expression and their clinical implication in OSCC.

METHODS

Fifty patients with primary OSCC were included in the study. Primary cancer cells and matched normal oral epithelium were purified by laser capture microdissection. RNA were extracted from these samples. The expression levels of miR-372 and miR-373 in the tissue of OSCC patients were measured by quantitative reverse transcription polymerase chain reaction. The large tumor suppressor kinase 2 (LATS2) protein expression level was measured by Western blotting.

RESULTS

Both miR-372 and miR-373 was up-regulated in OSCC tissue relative to control mucosa. Among different clinical variables, over-expression of miR-372 and miR-373 were associated with nodal metastasis, lymphovascular invasion, and poor survival. Multivariate analysis showed that both high miR-372 and miR-373 expression were independent predictors for poor survival in OSCC. MiR-372 regulated LATS2 expression in OSCC cell lines. LATS2 expression levels are inversely correlated miR-372 in OSCC tissues.

CONCLUSION

Over-expression of miR-372 and miR-373 indicate worse survival in OSCC.

LEVEL OF EVIDENCE

N/A.

Co-targeting of multiple microRNAs on factor-Inhibiting hypoxia-Inducible factor gene for the pathogenesis of head and neck carcinomas

BACKGROUND

MicroRNAs (miRNAs) are short, noncoding RNAs that inhibit the expression of target genes that play roles in tumorigenesis. MiR-21, miR-31, and miR-184 are oncogenic miRNAs for head and neck squamous cell carcinoma (HNSCC). Factor-inhibiting hypoxia (FIH)-inducible factor is known to inactivate hypoxia-induced downstream effectors and is involved in HNSCC suppression. This study investigates whether miR-21, miR-31, and miR-184 target FIH in HNSCC.

METHODS

Reporter assays, Western blot analysis, quantitative reverse transcriptase-polymerase chain reaction (PCR) analysis, and phenotypic assays were used to prove that miR-21, miR-31, and miR-184 directly target FIH. Clinicopathological implications of the gene expression were also analyzed.

RESULTS

MiR-21, miR-31, and miR-184 directly bind to various sites in the 3' untranslated region (UTR) of FIH transcript, and this binding is associated with decreased FIH protein expression in HNSCC cells. Treatment with the precursors of these miRNAs increases the proliferation and migration of HNSCC cells. Concomitant treatment with precursors repressed FIH and enhanced oncogenicity most profoundly. Upregulation of miR-21, miR-31, and miR-184 expression is found in more than 80% of HNSCC tumors and 72% of tumors have concordant upregulation of these 3 oncogenic miRNAs. The highest expression of these miRNAs is present in T4b and stage IVB tumors. Downregulation of FIH mRNA expression is noted in 69% of HNSCC tumors, and in tumors exhibiting high expression of these miRNAs, the FIH mRNA expression is consistently downregulated.

CONCLUSION

This study provides novel clues indicating that miR-21, miR-31, and miR-184 co-target FIH tumor suppressor during pathogenesis in the vast majority of HNSCC.