Oral Squamous Cell Carcinoma Tumor Research Articles

Decreased Cytoplasmic Expression of ADAMTS14 Is Correlated with Reduced Survival Rates in Oral Squamous Cell Carcinoma Patients.

A disintegrin and metalloproteinase with thrombospondin motif 14 (ADAMTS14) is a member of the zinc-dependent protease family that is implicated in the occurrence and progression of tumors. Oral cancer (OC) is a common cancer worldwide, but it is particularly prevalent in Taiwan. However, whether the expression of ADAMTS14 is correlated with the carcinogenesis and progression of oral squamous cell carcinoma (OSCC) has not yet been investigated. In this study, we used immunohistochemistry (IHC) to examine 250 OSCC specimens in order to identify correlations between the cytoplasmic expression of ADAMTS14 and (1) clinicopathological features of OSCC as well as (2) clinical outcomes of OSCC. Our results indicate that cytoplasmic expression of ADAMTS14 was lower in OSCC tissues than in normal tissues. In analyzing correlations between ADAMTS14 expression and clinicopathological features, we found that negative cytoplasmic expression of ADAMTS14 was significantly associated with higher frequencies of lymph node metastasis and more advanced AJCC stages (III/IV). Kaplan–Meier survival analysis revealed that negative cytoplasmic expression of ADAMTS14 was also associated with significantly worse OSCC survival. Univariate and multivariate analyses confirmed that cytoplasmic expression of ADAMTS14 was associated with lymph node metastasis, tumor stage, and tumor grade and also indicated that cytoplasmic ADAMTS14 expression may be an independent prognostic factor for OSCC. This is the first study to report that the cytoplasmic expression level of ADAMTS14 is associated with OSCC prognosis and tumor progression. Our data indicate that ADAMTS14 can serve as a prognostic marker and a potential therapeutic target for OSCC.

The TRPV4-AKT axis promotes oral squamous cell carcinoma cell proliferation via CaMKII activation

Most human malignant tumor cells arise from epithelial tissues, which show distinctive characteristics, such as polarization, cell-to-cell contact between neighboring cells, and anchoring to a basement membrane. When tumor cells invaginate into the stroma, the cells are exposed to extracellular environments, including the extracellular matrix (ECM). Increased ECM stiffness has been reported to promote cellular biological activities, such as excessive cellular growth and enhanced migration capability. Therefore, tumorous ECM stiffness is not only an important clinical tumor feature but also plays a pivotal role in tumor cell behavior. Transient receptor potential vanilloid 4 (TRPV4), a Ca2+-permeable nonselective cation channel, has been reported to be mechano-sensitive and to regulate tumorigenesis, but the underlying molecular mechanism in tumorigenesis remains unclear. The function of TRPV4 in oral squamous cell carcinoma (OSCC) is also unknown. The current study was conducted to investigate whether or not TRPV4 might be involved in OSCC tumorigenesis. TRPV4 mRNA levels were elevated in OSCC cell lines compared with normal oral epithelial cells, and its expression was required for TRPV4 agonist-dependent Ca2+ entry. TRPV4-depleted tumor cells exhibited decreased proliferation capabilities in three-dimensional culture but not in a low-attachment plastic dish. A xenograft tumor model demonstrated that TRPV4 expression was involved in cancer cell proliferation in vivo. Furthermore, loss-of-function experiments using siRNA or an inhibitor revealed that the TRPV4 expression was required for CaMKII-mediated AKT activation. Immunohistochemical analyses of tissue specimens obtained from 36 OSCC patients showed that TRPV4 was weakly observed in non-tumor regions but was strongly expressed in tumor lesions at high frequencies where phosphorylated AKT expression was frequently detected. These results suggest that the TRPV4/CaMKII/AKT axis, which might be activated by extracellular environments, promotes OSCC tumor cell growth.

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.

Functional blockade of cancer-associated fibroblasts with ultrafine gold nanomaterials causes an unprecedented bystander antitumoral effect.

Cancer-associated fibroblasts (CAFs) play a critical role in the onset and progression of malignancies, such as oral squamous cell carcinoma (OSCC), making CAFs a promising druggable target. In this study, gold nanoparticles (GNPs) exhibited unprecedented size dependent anti-CAF potential, wherein the smallest GNPs outperformed their larger counterparts. Specifically, a subset of proteins and cytokines that is responsible for the invasive outgrowth of OSCC cells was found to decrease post exposure of OSCC patient-derived CAFs to GNPs. Moreover, the administration of GNPs (3 nm in diameter) could effectively abrogate the growth of OSCC tumors in vivo, offering a novel means to manage OSCC in the clinic. Besides targeting cancer cells, our results collectively verify the feasibility of blocking dominant cells in the microenvironment to eradicate tumors, shedding light on the future design of nanomedicines.

Long non-coding RNA RBM5-AS1 promotes the aggressive behaviors of oral squamous cell carcinoma by regulation of miR-1285-3p/YAP1 axis

The human genome encodes far more long non-coding RNA (lncRNA) genes than protein coding genes. However, the function of majority of the lncRNAs is poorly understood. Numerous lncRNAs were aberrantly expressed in various cancers and found to be associated with development and progression of cancer. Little is known about the role of lncRNAs in oral squamous cell carcinoma (OSCC). In this study, we identified lncRNA RBM5-AS1 to be highly expressed in OSCC tumor tissues and cancer cell lines. RBM5-AS1 promotes the proliferation, migration, and invasion of OSCC cells in vitro. We also found that RBM5-AS1 regulates the level of miR-1285-3p as a competitive endogenous RNA (ceRNA), therefore regulate the expression level of an oncogene-YAP1, a target of miR-1285-3p. The information obtained in this study is valuable for understanding the regulatory mechanism of lncRNA in the development of OSCC and for developing new strategies for the diagnosis and treatment of OSCC.

MTFP1 overexpression promotes the growth of oral squamous cell carcinoma by inducing ROS production.

Mitochondrial fission process 1 (MTFP1) is a novel nuclear-encoded protein that promotes mitochondrial fission. Increasing lines of evidence indicate that increased mitochondrial fission is involved in carcinogenesis and tumor progression. However, the expression and biological effects of MTFP1 in cancer development is still unclear, especially in oral squamous cell carcinoma (OSCC). In this study, we first evaluated the expression of MTFP1 in 12-paired OSCC tumor and peritumor tissues. We then explored the effects of MTFP1 knockdown or overexpression on cell growth by cell proliferation, colony formation, cell cycle, and cell apoptosis assays. Furthermore, the mechanisms by which MTFP1 promoted OSCC cell growth were explored. Our results showed that MTFP1 is frequently overexpressed in OSCC tissues. Functional experiments revealed that MTFP1 promoted the growth of OSCC cells by inducing the progression of cell cycle and suppressing cell apoptosis. Mechanistically, MTFP1 overexpression-mediated mitochondrial fragmentation and subsequent ROS production was found to be involved in the promotion of OSCC cell growth. Collectively, our study demonstrates that MTFP1 plays a critical oncogenic role in OSCC carcinogenesis, which may serve as a potential therapeutic target in the treatment of this malignance.

Piwi-Interacting RNA1037 Enhances Chemoresistance and Motility in Human Oral Squamous Cell Carcinoma Cells.

BackgroundPiwi-interacting RNAs (piRNAs) are thought to silence transposable genetic elements. However, the functional roles of piRNAs in oral squamous cell carcinoma (OSCC) remain unelucidated. In the present study, we aimed to investigate the role of Piwi-interacting RNA 1037 (piR-1037) in chemoresistance to cisplatin (CDDP)-based chemotherapy and the oncogenic role of piR-1037 in OSCC cells.MethodsRT-PCR was used to evaluate the levels of piR-1037 and X-linked Inhibitor of apoptosis protein (XIAP) mRNA in OSCC cell lines or tumor xenografts. Transfection of piR-1037 DNA antisense and piR-1037 RNA oligonucleotides was performed to suppress and overexpress piR-1037 in OSCC cells, respectively. A CCK8 assay was used to measure the viability or proliferation of OSCC cells. Apoptosis in OSCC cells and xenografts was determined using a TUNEL assay kit. The activity of caspase-3, caspase-8 and caspase-1 in OSCC cells was measured with colorimetric caspase assay kits. Western blot analysis was conducted to analyze XIAP expression in OSCC cells and xenograft samples. Immunoprecipitation (IP) and RNA pull-down assays were utilized to analyze the piR-1037 - XIAP interaction. Transwell assays were performed to evaluate migration and invasion of OSCC cells.ResultsCDDP treatment upregulated piR-1037 expression in OSCC cells and OSCC xenografts. Suppression of the CDDP-induced upregulation of piR-1037 expression enhanced the sensitivity of OSCC cells to CDDP. piR-1037 promoted protein expression and directly bound XIAP, a key apoptotic inhibitor that is implicated in chemoresistance. The relationship between piR-1037 and XIAP suggested that piR-1037 enhanced OSCC cell chemoresistance to CDDP at least partially through XIAP. Moreover, targeting the basal expression of piR-1037 inhibited cell motility by affecting epithelial–mesenchymal transition (EMT).ConclusionpiR-1037 enhances the chemoresistance and motility of OSCC cells. piR-1037 promotes chemoresistance by interacting with XIAP and regulates the motility of OSCC cells by driving EMT.

A decision analysis model for elective neck dissection in patients with cT1-2 cN0 oral squamous cell carcinoma.

SUMMARYNeck metastasis from oral squamous cell carcinoma (OSCC) has a significant impact on disease-specific and overall survival. Physical examination and imaging exams are used to stage the neck, but preoperative neck staging cannot reliably differentiate between metastatic and non-metastatic nodes. The decision to perform elective neck dissection (END) should consider the probability of neck metastasis and the harm of unnecessary surgery. We evaluate if this model can be used to decide treatment and the net benefit with different strategies. We reviewed patients treated from January, 1985 to December, 2012. Inclusion criteria were histological diagnosis of OSCC, initial surgery and primary tumour in the oral cavity staged as cT1-2 cN0. Development of a predictive model for metastatic nodes used patients submitted to END. The probability of neck metastasis was calculated and decision curve analysis was performed. We considered two interventions: watchful waiting and END, and two outcomes, regional recurrence and disease-free survival. We developed the model using logistic regression after multiple inputs with neck metastasis as an outcome. The initial model included all demographic and pathological variables. This model has an area under the curve (AUC) of 0.8423, a positive predictive value (PPV) of 70.7% and a negative predictive value (NPV) of 80.2%. We used LASSO for coefficient reduction and variable selection. This model has an AUC of 0.8265 with PPV of 68.3% and NPV of 80.2%. For neck recurrence, the curves of “treat all by watchful waiting” and “treat none by watchful waiting” crossed at the prevalence of neck metastasis. When focusing on disease-free survival, the decision analysis curve shows a pattern where the predictive model provides a net benefit if used to choose treatment from a 20% until a 54% threshold.

Fenretinide, Tocilizumab, and Reparixin Provide Multifaceted Disruption of Oral Squamous Cell Carcinoma Stem Cell Properties: Implications for Tertiary Chemoprevention.

Locoregional recurrence of oral squamous cell carcinoma (OSCC) dramatically reduces patient survival. Further, as many OSCC recurrences are inoperable, radiotherapy and chemotherapy with or without biological adjuncts are the remaining treatment options. Although the tumors may initially respond, radiotherapy- and chemotherapy-resistant cancer stem cells (CSC) can readily repopulate OSCC tumors. Currently, following the initial OSCC treatment, patients are closely monitored until a recurrence or a second primary is detected. Identification of agents with complementary mechanisms to suppress CSC tumorigenic functions could change this passive approach. The goals of this study were twofold: (1) develop and validate CSC-enriched (CSCE) OSCC cell lines and (2) identify chemopreventive agents that obstruct multiple CSCE protumorigenic pathways. CSCE cultures, which were created by paclitaxel treatment followed by three tumorsphere passes, demonstrated CSC characteristics, including increased expression of stem cell and inflammatory genes, increased aldehyde dehydrogenase (ALDH) activity, and enhanced in vitro/in vivo proliferation and invasion. Three chemopreventives, fenretinide, tocilizumab, and reparixin, were selected due to their distinct and complementary CSC-disruptive mechanisms. The CSCE selection process modulated the cells' intermediate filaments resulting in an epithelial-predominant (enhanced cytokeratin, proliferation, IL6 release) line and a mesenchymal-predominant (upregulated vimentin, invasive, IL8 release) line. Our results confirm that 4HPR binds with appreciably higher affinity than Wnt at the Frizzled binding site and significantly inhibits CSC-enabling Wnt-β-catenin downstream signaling. Notably, combination fenretinide-tocilizumab-reparixin treatment significantly suppressed IL6 and IL8 release, stem cell gene expression, and invasion in these diverse CSCE populations. These promising multiagent in vitro data provide the basis for our upcoming in vivo CSCE tertiary chemoprevention studies.

CD109 acts as a gatekeeper of the epithelial trait by suppressing epithelial to mesenchymal transition in squamous cell carcinoma cells in vitro

There is increasing evidence that the expression of CD109, a GPI-anchored cell surface protein is dysregulated in squamous cell carcinoma (SCC). However, the functional role of CD109 in SCC progression is poorly understood. In current study, we demonstrate that CD109 is a critical regulator of epithelial phenotype in SSC cells. CD109 levels inversely correlate with TGF-β signaling, EMT, migration, and invasion in cultured SCC cells. CRISPR/Cas9-mediated knockout CD109 (CD109 KO) in SCC cells represses epithelial traits and promotes the mesenchymal phenotype, as evidenced by elevated expression of mesenchymal proteins and markers of epithelial to mesenchymal transition. Treatment with recombinant CD109 protein causes CD109 KO cells to regain their epithelial traits. CD109 loss results in pronounced alterations of gene expression as detected by microarray analysis and in dysregulation of 15 important signalling pathways as shown by KEGG pathway cluster analysis. Validation using 52 human oral SCC tumor samples show that CD109 levels inversely correlate with tumor grade and the activation state of one such pathway, the TGF-β signaling pathway. Taken together, our findings highlight a novel role for CD109 as a gatekeeper of the epithelial phenotype by regulating TGF-β pathway in SCC cells.

LINC01234 facilitates growth and invasiveness of oral squamous cell carcinoma through regulating the miR-637/NUPR1 axis

LINC01234 plays a pivot role in the tumorigenesis of gastric cancer, colon cancer and lung cancer. However, how LINC01234 participates in oral squamous cell carcinoma (OSCC) progression remains unknown. In our research, we showed that LINC01234 was dramatically upregulated in OSCC tissues. And interestingly, high LINC01234 expression predicted a low overall survival rate in OSCC patients. Knockdown of OSCC inhibited the proliferation of cancer cells and led to more cells restricted in G0 phase. Moreover, LINC01234 silencing decreased the migration and invasion of OSCC cells. Additionally, downregulation of LINC01234 limited OSCC tumor propagation in vivo. Mechanistic investigation elucidated that LINC01234 inhibited the activity of miR-637 to increase the expression of NUPR1. Via upregulating NUPR1 level, LINC01234 contributed to malignant behaviors of OSCC cells. Collectively, our research shows that LINC01234 exerts an important role in OSCC progression via miR-637/NUPR1 axis.

Cigarette smoke, saliva, the translocator protein 18 kDa (TSPO), and oral cancer

Oral squamous cell carcinoma (OSCC) incidence is induced primarily by cigarette smoke (CS). The 5-year survival rate for advanced OSCC stands at only 20%. Studies exploring underlying mechanisms of OSCC development have suggested free radicals such as reactive oxygen species generated by CS as contributing to OSCC, with effects enhanced by transition metal ions iron and copper contained in the saliva. Located on the outer mitochondrial membrane of various cell types, the 18-kDa translocator protein (TSPO) is up-regulated under pathological conditions such as cancer and inflammation. We focused on studying the interaction between TSPO, CS, salivary effects, and OSCC. Increased TSPO expression in OSCC tumors correlates significantly with reduced patient survival rate, indicating the possible role of TSPO in OSCC pathogenesis. We speculate that TSPO in OSCC is dysfunctional or mutated, rendering it ineffective in promoting apoptosis and blocking malignant transformation. Basal, precancer lower function of TSPO may diminish the TSPO capacity for pro-apoptotic and anti-cancer activity, resulting in development of OSCC. In order to overcome this, TSPO over-expression is induced, unfortunately with no benefit, as it is a malfunctioning TSPO, similar to cases where over-expression of a mutated form of the p53 gene in tumors is associated with carcinogenesis.

19P - The inhibitory effect in oral squamous cell carcinoma cells by knocking down matrix metalloproteinase 9

BackgroundExtracellular matrix (ECM) is a basic step of tumor invasion and metastasis. Matrix metalloproteinase (MMPs) family is a kind of zinc-ion-dependent endopeptidase, which can degrade almost all protein components in the extracellular matrix, destroy the histological barrier of tumor cell invasion, and play a key role in tumor invasion and metastasis. The role of MMP-9 in tumor invasion and metastasis has attracted increasing attention and is considered as the main proteolytic enzyme in this process. The aim of this study was to investigate the role of MMP-9 in human oral squamous cell carcinoma cells. MethodsHuman oral squamous cell carcinoma (OSCC) cells CAL27 and SCC-15 were cultured in DMEM high glucose medium with 10% FBS. The MMP-9-shRNA Lentiviral clone and control virus was constructed and transfected into OSCC cells. Cell proliferation was detected by MTT assay. Colony formation was evaluated by colony formation assay. Cell migration and invasion was evaluated using the scratch assay and transwell invasion assay. OSCC cells Knockdown with MMP-9-shRNA were injected into zebra fish and OSCC tumor model in zebra fish was established and evaluated. ResultsMMP-9 expression was down regulated significantly in RNA and protein level after transfection. Knockdown of MMP-9 gene by shRNA could inhibit oral squamous cell cancer cells growth and colony formation, and markedly suppress cell migration and invasion in vitro. And also knockdown of MMP-9 gene could significantly inhibit OSCC cells metastasis in zebra fish. ConclusionsMMP-9 plays an important role in OSCC cells metastasis. Legal entity responsible for the studyBeijing Stomatological Hospital & School of Stomatology, Capital Medical University. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

The Highly Pure Neem Leaf Extract, SCNE, Inhibits Tumorigenesis in Oral Squamous Cell Carcinoma via Disruption of Pro-tumor Inflammatory Cytokines and Cell Signaling.

Oral squamous cell carcinoma (OSCC) is a deadly disease that comprises 60% of all head and neck squamous cell cancers. The leaves of the Neem tree (Azadirachta indica) have been used in traditional Ayurvedic medicine for centuries to treat numerous oral maladies and are known to have significant anti-inflammatory properties. We hypothesize that a highly pure super critical CO2 Neem leaf extract (SCNE) prevents initiation and progression of OSCC via downregulation of intra-tumor pro-inflammatory pathways, which promote tumorigenesis. Hence, we investigated the anticancer effects of SCNE using in vitro and in vivo platforms. OSCC cell lines (SCC4, Cal27, and HSC3) were treated with SCNE while inflammation, proliferation, and migration were analyzed over time. SCNE treatment significantly inhibited OSCC cell proliferation and migration and reduced MMP activity in vitro, suggesting its potential to inhibit tumor growth and metastasis. The preventive effects of SCNE in ectopic xenograft and 4NQO-1 (4-Nitroquinoline-1-oxide) carcinogen-induced mouse models of OSCC were also evaluated. Indeed, xenografted nude mice showed significant reduction of OSCC tumor volumes. Likewise, SCNE significantly reduced the incidence of tongue dysplasia in the 4NQO-1 OSCC initiation model. In both OSCC animal models, SCNE significantly depressed circulating pro-cancer inflammatory cytokines (host and tumor-secreted) including NFkB, COX2, IL-1, IL-6, TNFα, and IFNγ. In addition, we demonstrate that SCNE downregulates STAT3 and AKT expression and activity in vitro. We also demonstrate that the primary active component, nimbolide (NIM), has significant anticancer activity in established OSCC xenografts. Lastly, we show that SCNE induces an M1 phenotype in tumor associated macrophages (TAMS) in vivo. Taken together, these data strongly support SCNE as means of preventing OSCC via downregulation of pro-cancer inflammatory cascades and NIM as a potential new therapy for existing OSCC.

Downregulation of FOXP3 in neutrophils by IL-8 promotes the progression of oral squamous cell carcinoma.

The aim of the present study was to investigate the effects of the transcription factor forkhead box P3 (FOXP3) in neutrophils on the progression of oral squamous cell carcinoma (OSCC). Cancer tissue samples and paracarcinoma tissues were collected from 23 patients with OSCC for the current study. In addition, SCC-9, a human tongue carcinoma cell line, was co-cultured with primary human neutrophils and treated with recombinant interleukin 8 (IL-8). The effect of FOXP3 on the proliferation of SCC-9 cells was analyzed using a Cell Counting Kit 8 assay. FOXP3 expression in neutrophils was analyzed by quantitative PCR following IL-8 treatment. FOXP3 protein expression in neutrophils and the amount of IL-8 protein in the OSCC tumor microenvironment were determined by immunofluorescence analysis. The present study demonstrated that IL-8 downregulated FOXP3 mRNA expression in neutrophils. Neutrophils and peptide P60, a specific inhibitor of FOXP3, increased proliferation of SCC-9 cells. In patients with OSCC, FOXP3 protein expression in neutrophils of the stage IV group was significantly lower compared with that of the stage II and stage III groups, while IL-8 protein expression was higher in cancer tissues compared with that in paracarcinoma tissues. In summary, IL-8 in the tumor microenvironment may recruit neutrophils, and downregulation of FOXP3 in neutrophils by IL-8 may promote the progression of OSCC.

Aberrantly hypermethylated tumor suppressor genes were identified in oral squamous cell carcinoma (OSCC)

BackgroundOral squamous cell carcinoma (OSCC) is a genetic and epigenetic disease. There is growing evidence to suggest that environmental factors due to epigenetic changes can be involved in the OSCC pathogenesis. Although tumor suppressor genes (TSGs) are commonly inactivated by promoter hypermethylation in human cancers, the epigenetic changes and the mechanism of TSGs in human OSCC remain unclear. We therefore assessed the methylation status of the TSGs, which are associated with epigenetic silencing in human cancers, OSCC cell lines, primary tumors, and normal oral mucosa.ResultsWe used 14 TSGs that were originally identified in colon cancer to investigate the aberrant hypermethylation of these genes associated with transcriptional silencing in 10 OSCC cell lines. We found three TSGs, TFPI2, SOX17, and GATA4, that are robustly hypermethylated and are associated with transcriptional silencing in OSCC cell lines. The re-expression of the three genes was induced by 5-aza-2′-deoxycytidine (5-aza-dC) in cells in which these genes were not expressed or had a lack of expression. In 33 cases of primary OSCC tumors, promoter hypermethylation was detected for the TFPI2, SOX17, and GATA4 genes at (32/33) 97%, (22/33) 67%, and (11/33) 33%, respectively. Eleven normal oral mucosa samples showed no promoter hypermethylation for all three genes, which suggests that this promoter hypermethylation is cancer-specific. Bisulfite sequencing analysis confirmed the cancer-specific methylation of the TFPI2, SOX17, and GATA4 promoters in the OSCC cell lines and tumors but not in the normal oral mucosa samples. More importantly, the methylation status of TFPI2, GATA4, and SOX17 was significantly associated with OSCC patients’ overall survival through TCGA DNA methylation database.ConclusionsWe identified that TFPI2, SOX17, and GATA4 are frequently hypermethylated in human OSCC cells in a cancer-specific manner and that the transcriptional expression of these genes is regulated by promoter hypermethylation in OSCC. Our results highlight the great potential used as a synergistic biomarker set to improve the prognosis and therapeutic treatment for patients with OSCC.

In situ measurement of miR-138 expression in oral squamous cell carcinoma tissue supports the role of this microRNA as a tumor suppressor.

Oral squamous cell carcinoma is the eighth most common cancer worldwide with a relatively high rate of metastasis (~40%). Previously, we showed that microRNA-138 serves as a functional tumor suppressor and plays an important role in oral squamous cell carcinoma metastasis. However, to date, microRNA-138 expression has not been examined in this tumor tissue. Herein, we demonstrated that microRNA-138 expression is downregulated in metastatic oral squamous cell carcinoma specimens using tissue microarray technology with in situ hybridization. The study included 254 oral squamous cell carcinoma patients from two centers (160 from the Chengdu center and 90 from the Guangzhou center) and four healthy volunteers. Multivariate analysis showed that microRNA-138 expression was independent of tumor stage, age, gender, smoking, and alcohol consumption in oral squamous cell carcinoma patients. Interestingly, patients that expressed lower levels of microRNA-138 (determined by in situ hybridization) were more prone to regional lymph node metastasis and exhibited poorer outcomes. These findings support the role of microRNA-138 as a tumor suppressor in oral squamous cell carcinoma. In summary, the expression level of microRNA-138 is negatively correlated with oral squamous cell carcinoma metastasis; the lower the expression of microRNA-138, the higher the rate of metastasis and the poorer the prognosis of the patients. Therefore, our study confirms that microRNA-138 serves as a tumor suppressor and plays a functional role in oral squamous cell carcinoma tumor metastasis; microRNA-138 constitutes a promising prognosis biomarker and therapeutic target for oral squamous cell carcinoma with metastasis potential.

RANKL triggers resistance to TRAIL-induced cell death in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) occurs as a malignancy of the oral cavity. RANK ligand (RANKL) is essential for osteoclast formation/bone resorption. Recently, we showed autoregulation of receptor activator of nuclear factor-κB ligand (RANKL) stimulates OSCC cell proliferation. OSCC cells show resistance to tumor necrosis factor related apoptosis inducing ligand (TRAIL) treatment. Therefore, we hypothesize that RANKL promotes resistance for TRAIL induction of OSCC apoptotic cell death. In this study, SCC14A and SCC74A cells cultured with TRAIL revealed high-level expression of RANKL which increased resistance to TRAIL inhibition of tumor cell proliferation. RANKL stimulation inhibited terminal deoxynucleotidyl transferase dUTP nick end labeling positive staining in TRAIL-treated cells. CRISPR/Cas-9 knockout of RANKL (RANKL-KO) increased caspase-9, caspase-3 activity and cytochrome c release in OSCC cells. RANKL inhibited proapoptotic proteins BAD and BAX expression. TRAIL treatment suppressed the SQSTM1/p62 and RANKL restored the expression. Interestingly, RANKL alone significantly increased proteasome activity. RANKL-KO in OSCC cells inhibited autophagic activity as evidenced by decreased light chain 3B-II and beclin-1 expression. Thus, RANKL stimulation of OSCC tumor cells triggered resistance for TRAIL-induced OSCC cell death. Taken together, blockade of RANKL may inhibit OSCC tumor progression and enhance the potential of TRAIL induced OSCC tumor cell apoptosis.

Increased LGALS3BP promotes proliferation and migration of oral squamous cell carcinoma via PI3K/AKT pathway

Previous studies showed that lectin galactoside-binding soluble 3 binding protein (LGALS3BP) is an important participant in tumor progression. However, its prognostic value and functional mechanism in oral squamous cell carcinoma (OSCC) are still unclear. In this study, we analyzed LGALS3BP expression in OSCC tissues via Oncomine databases and immunohistochemical staining. LGALS3BP was significantly up-regulated in OSCC tumor tissues. IHC analysis showed that LGALS3BP was predominantly expressed in tumor cells and correlated with poor clinical characteristics. In addition, high LGALS3BP expression predicted poor clinical outcomes and multivariate analysis revealed that LGALS3BP expression was as an independent prognostic factor for OS, DFS and RFS (p < .0001, p = .002, p = .002). Mechanically, LGALS3BP regulated OSCC proliferation and migration via PI3K/AKT pathways, which was abrogated by PI3K inhibitor LY294002 in a dose-dependent manner. Our results suggested that LGALS3BP could be served as a novel independent prognostic factor as well as a potential therapeutic target for OSCC treatment.

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

Abstract 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.