Inhibited Oral Squamous Cell Carcinoma Cell Research Articles

Effect of circular RNA hsa_circ_0008898 on oral squamous cell carcinoma and its mechanism

Objective: To investigate the effect and molecular mechanism of hsa_circ_0008898 on the cell proliferation, migration, invasion and tumor formation of oral squamous cell carcinoma (OSCC). Methods: Quantitative real-time PCR (qPCR) and Western blotting were used to detect the expression of hsa_circ_0008898, miR-197-5p and ras homolog gene family member A (RHOA) in OSCC tissues, adjacent tissues, OSCC cells and human normal oral keratinocytes (NOK). CAL27 and SCC-25 cells were transfected with si-hsa_circ_0008898#1 (knockdown group 1), si-hsa_circ_0008898#2 (knockdown group 2), hsa_circ_0008898 (circ overexpression group) and blank plasmid (circ blank group), respectively. Then miR-197-5p inhibitor (inhibition group) and blank plasmid (inhibition control group) were transfected into hsa_circ_0008898 knockdown cells (knockdown group 1). CAL27 and SCC-25 cells were transfected with miR-197-5p mimics (miR overexpression group) and blank plasmid (miR blank group), and then transfected hsa_circ_0008898 vector (co-transfection group 1), RHOA vector (co-transfection group 2) and blank plasmid (co-transfection control group) in cells overexpressing miR-197-5p. Cell counting kit 8 (CCK-8), colony formation, Transwell and scratch test were used to detect cell proliferation, cloning ability, cell cycle distribution, cell invasion and migration ability. Ten nude mice were equally divided into two groups, with 5 mice in each group. SCC-25 cells transfected with blank plasmid (control group) and SCC-25 cells transfected with sh-hsa_circ_0008898 (knockout group) were subcutaneously injected into the armpit. The volume and mass of the tumor were measured. Results: The expressions of hsa_circ_0008898 (2.89±0.72) and RHOA (2.62±0.21) in OSCC tissues were significantly higher than those in para-carcinoma tissues (1.00±0.48, 1.00±0.11, respectively), while the expression of miR-197-5p in OSCC tissues （0.46±0.24） was significantly lower than that in para-carcinoma tissues (1.00±0.42) (P<0.05). Compared with NOK, the expression of hsa_circ_0008898 and RHOA in CAL27 and SCC-25 cells increased significantly, while the expression of miR-197-5p decreased (P<0.05). Compared with circ blank group, the cell viability, colony formation, scratch healing rate and invasive cell number of CAL27 and SCC-25 cells in knockdown group 1 and group 2 were significantly decreased, while the proportion of cells in G1 phase was significantly increased (P<0.05). Compared with inhibition control group, the cell viability, colony formation, scratch healing rate and invasive cell number of CAL27 and SCC-25 in inhibition group were significantly increased, while the proportion of cells in G1 phase was significantly decreased in inhibition group (P<0.05). Compared with miR blank group, the cell viability, colony formation, scratch healing rate and invasive cell number of CAL27 and SCC-25 in miR overexpression group were significantly decreased, while the proportion of cells in G1 phase was significantly increased in miR overexpression group (P<0.05). Compared with co-transfection control group, the cell viability, colony formation, migration area and invasive cell number of CAL27 and SCC-25 in co-transfection group2 were significantly increased, while the proportion of cells in G1 phase was significantly decreased in co-transfection group 2 (P<0.05). The volume and mass of transplanted tumor in knockout group ［(660.4±67.8) mm(3 )and (0.60±0.06) g, respectively］ were significantly lower than those in control group ［(1 210.4±198.9) mm(3) and (1.00±0.12) g, respectively］. Conclusions: Knockdown of hsa_circ_0008898 inhibited OSCC cells proliferation, cloning, migration and invasion and induced cell cycle arrest in vitro by regulating the miR-197-5p/RHOA. Additionally, Knockdown of hsa_circ_0008898 also inhibited tumor formation of OSCC cells in vivo.

Circular RNA ITCH Suppresses Cell Proliferation but Induces Apoptosis in Oral Squamous Cell Carcinoma by Regulating miR-421/PDCD4 Axis.

BackgroundCircular RNAs (circRNAs), a group of covalently closed non-coding RNAs, serve critical regulatory roles in many human cancers, including oral squamous cell carcinoma (OSCC). The purpose of this study was to investigate the functional role of circular RNA ITCH (circ-ITCH) in OSCC and the underlying mechanisms.Methods RT-qPCR analysis was applied to detect the expression levels of circ-ITCH in OSCC tissues and cell lines. MTT assay and flow cytometer analysis were used to evaluate the effects of circ-ITCH overexpression on the proliferation and apoptosis of OSCC cells. Bioinformatics analysis and dual-luciferase reporter assay were applied to determine the binding relation between circ-ITCH and miR-421 as well as PDCD4 mRNA and miR-421.ResultsOur results showed that circ-ITCH expression was remarkably decreased in OSCC tissues and cell lines. Low circ-ITCH expression was strongly associated with adverse clinicopathological characteristics of OSCC patients. Moreover, functional assays demonstrated that circ-ITCH overexpression significantly inhibited OSCC cell proliferation and induced cell apoptosis. Our data further uncovered that circ-ITCH could bind directly to miR-421 and block its repression on PDCD4 in OSCC. MiR-421 expression was significantly increased in OSCC tissues and was inversely correlated with circ-ITCH expression. Notably, miR-421 restoration blocked the tumor-suppressive role of circ-ITCH in OSCC cells.ConclusionIn conclusion, our study reveals that circ-ITCH serves as a tumor suppressor in OSCC partly by regulating miR-421/PDCD4 axis.

Activation of PGK1 under hypoxic conditions promotes glycolysis and increases stem cell‑like properties and the epithelial‑mesenchymal transition in oral squamous cell carcinoma cells via the AKT signalling pathway.

Although it has been previously documented that a hypoxic environment can promote glycolysis and the malignant progression of oral squamous cell carcinoma (OSCC) cells, the specific underlying mechanism remains unclear. Phosphoglycerate kinase 1 (PGK1) has been previously reported to serve an important role in tumor metabolism. The aim of the present study was to investigate the effects of hypoxia and PGK1 on glycolysis, stem cell-like properties and epithelial-mesenchymal transition (EMT) in OSCC cells. Cell Counting Kit-8 assays were performed to examine tumor cell viability under hypoxic conditions. Sphere formation, immunohistochemistry, western blotting, Transwell assays and mouse xenograft studies were performed to assess the biological effects of PGK1. Under hypoxic conditions, phosphoglycerate PGK1 expression was found to be upregulated, which resulted in the potentiation of stem cell-like properties and enhancement of EMT. However, PGK1 knockdown reversed hypoxia-mediated glycolysis, stem cell-like properties, EMT in addition to inhibiting OSCC cell invasion and migration. PGK1 knockdown also inhibited tumour growth, whilst the overexpression of PGK1 was demonstrated to promote tumour growth in mouse xenograft models in vivo. Downstream, activation of the AKT signalling pathway reversed the series of changes induced by PGK1 knockdown. PGK1 expression was found to be upregulated in human OSCC tissues, which was associated with the pathological differentiation of tumours and lymph node metastasis. To conclude, results from the present study demonstrate that hypoxia can increase PGK1 expression, resulting in the promotion of glycolysis, enhancing stem cell-like properties and EMT by activating AKT signalling in OSCC.

Downregulation of PER2 Promotes Tumor Progression by Enhancing Glycolysis via the Phosphatidylinositol 3-Kinase/Protein Kinase B Pathway in Oral Squamous Cell Carcinoma

PER2 gene expression is downregulated in oral squamous cell carcinoma (OSCC) and may have a pivotal role in tumor suppression. However, the biological function and mechanism of action of PER2 in OSCC remain unclear. In this study, the biological functions and anticancer mechanisms of PER2 in OSCC were investigated. Both stably overexpressed and silenced PER2 OSCC cells were established as an experimental group; empty vector lentivirus and scramble short hairpin RNA lentivirus transfected-cells, as negative control groups; and untreated OSCC cells, as a blank group.Cell proliferation, apoptosis, and glycolysis potential assays were conducted. In addition, the expression of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), phosphorylation of protein kinase B, hexokinase 2 (HK2), pyruvate kinase M (PKM2), and lactate dehydrogenase A (LDHA) was quantified by real-time quantitative polymerase chain reaction and Western blotting.Rescue experiments were performed by the addition of AKT activators in the overexpressed cell line and by the addition of glycolysis inhibitor in the silenced cell line. These findings were verified invivo using stably transfected OSCC cells overexpressing PER2 implanted in nude mice. PER2 overexpression significantly inhibited OSCC cell proliferation and glycolysis, promoted cell apoptosis, and reduced the expression of PI3K, phosphorylation of protein kinase B, HK2, PKM2, and LDHA. The converse was observed in PER2-silenced OSCC cells. After the addition of AKT activator to cultures of PER2-overexpressed OSCC cells, reduced glucose uptake, lactic acid production, and cell proliferation, combined with increased apoptosis, were substantially reversed. In addition, after the addition of HK2 inhibitor to PER2-silenced OSCC cells to inhibit glycolysis, the reduction in apoptosis and increased proliferation were significantly countermanded. Tumorigenesis experiments invivo also confirmed that PER2 overexpression suppressed OSCC growth and decreased the expression of HK2, PKM2, and LDHA. PER2 heightened glycolysis via the PI3K/AKT pathway, heightened cell proliferation and inhibited apoptosis via glycolysis, thereby promoting the development of OSCC.

Nobiletin inhibits cell growth through restraining aerobic glycolysis via PKA-CREB pathway in oral squamous cell carcinoma.

Background/AimNobiletin is a polymethoxylated flavone enriched in Citrus and is used as an important drug in traditional Chinese medicine for various kinds of diseases. Among its multiple functions, it has shown that nobiletin inhibits proliferation of various cancer cells. However, it is unclear whether nobiletin inhibits the growth of oral squamous cell carcinoma (OSCC) cells.Materials and MethodsWe explored the antitumor effects of nobiletin in TCA‐8113 and CAL‐27 oral squamous cells. The Cell Counting Kit‐8 (CCK8) assay was used to measure cell vitality. Flow cytometry was performed to measure the number of cells in the various phases of the cell cycle. PCR and Western blot were applied to determine mRNA and protein expression, respectively.ResultsNobiletin inhibited proliferation of TCA‐8113 and CAL‐27 cells via inducing cell cycle arrest at the G1 phase. In addition, the levels of phosphorylated‐PKA and phosphorylated‐CREB were reduced in nobiletin‐treated TCA‐8113 and CAL‐27 cells. Importantly, our results showed that nobiletin treatment resulted in impaired mitochondrial function and altered glucose consumption, and pyruvate and lactate production. Lastly, nobiletin was found to inhibit the generation of xenografts in vivo. Interestingly, administration of 50 μmol/L Sp‐cAMP, a potent PKA activator, rescued all phenotypes caused by nobiletin.ConclusionsNobiletin inhibits OSCC cell proliferation in a mitochondria‐dependent manner, indicating that it may have a promising role in cancer treatment and attenuation of drug resistance.

Promotion of ubiquitination-dependent survivin destruction contributes to xanthohumol-mediated tumor suppression and overcomes radioresistance in human oral squamous cell carcinoma

BackgroundOverexpression of survivin plays a crucial role in tumorigenesis and correlates with poor prognosis in human malignancies. Thus, survivin has been proposed as an attractive target for new anti-tumor interventions.MethodsA natural product library was used for natural compound screening through MTS assay. The expression of survivin in oral squamous cell carcinoma (OSCC) and the inhibitory effect of xanthohumol (XN) on OSCC were examined by anchorage-dependent and -independent growth assays, immunoblot, immunofluorescence, immunohistochemical staining, ubiquitination analysis, co-immunoprecipitation assay, CRISPR-Cas9-based gene knockout, and xenograft experiment.ResultsSurvivin is highly expressed in OSCC patient-derived tissues and cell lines. Knockout of survivin reduced the tumorigenic properties of OSCC cells in vitro and in vivo. With a natural compound screening, we identified that xanthohumol inhibited OSCC cells by reducing survivin protein level and activating mitochondrial apoptotic signaling. Xanthohumol inhibited the Akt-Wee1-CDK1 signaling, which in turn decreased survivin phosphorylation on Thr34, and facilitated E3 ligase Fbxl7-mediated survivin ubiquitination and degradation. Xanthohumol alone or in combination with radiation overcame radioresistance in OSCC xenograft tumors.ConclusionOur findings indicate that targeting survivin for degradation might a promising strategy for OSCC treatment.

Tanshinone IIA inhibits oral squamous cell carcinoma via reducing Akt-c-Myc signaling-mediated aerobic glycolysis

Aerobic glycolysis is one of the hallmarks of human cancer cells. Overexpression of hexokinase 2 (HK2) plays a crucial role in the maintaining of unlimited tumor cell growth. In the present study, we found that the oral squamous cell carcinoma (OSCC) cells exhibited an aerobic glycolysis phenotype. Moreover, HK2 is highly expressed in OSCC patient derived-tissues and cell lines. Depletion of HK2 inhibited OSCC cell growth in vitro and in vivo. With a natural product screening, we identified Tanshinone IIA (Tan IIA) as a potential anti-tumor compound for OSCC through suppressing HK2-mediated glycolysis. Tan IIA decreased glucose consumption, lactate production, and promoted intrinsic apoptosis in OSCC cells. The mechanism study revealed that Tan IIA inhibited the Akt-c-Myc signaling and promoted E3 ligase FBW7-mediated c-Myc ubiquitination and degradation, which eventually reduced HK2 expression at the transcriptional level. In summary, these results indicate that targeting HK2-mediated aerobic glycolysis is a promising anti-tumor strategy for OSCC treatment.

MicroRNA-222-3p participates in the development of oral squamous cell carcinoma by targeting CDKN1B.

The aim of this study was to explore the potential role and regulatory mechanism of microRNA (miR)-222-3p in oral squamous cell carcinoma (OSCC). The expression level and prognostic significance of miR-222-3p was detected in OSCC tissues. CCK-8, transwell, and flow cytometry assays were used to explore the effect of miR-222-3p on cell proliferation, migration, invasion, and apoptosis. The influence of miR-222-3p on cyclin-dependent kinase inhibitor 1B (CDKN1B) expression was evaluated by luciferase assays, real-time polymerase chain reaction, and Western blot. We found that miR-222-3p was overexpressed in OSCC tissues, comparing with normal tissues. Kaplan-Meier curves showed that OSCC patients with high expression of miR-222-3p (P=.003) showed worse overall survival than those patients with low expression of miR-222-3p. Multivariate analysis showed that miR-222-3p (P=.037) expression was an independent prognostic factor of OSCC patients. miR-222-3p promoted cell proliferation, migration and invasion and induced the apoptosis of SCC-15 and Tca-83 cells. Furthermore, luciferase reporter assays indicated that CDKN1B is targeted by miR-222-3p in OSCC cells. Overexpression of CDKN1B inhibited OSCC cell proliferation, migration, and invasion and promoted cell apoptosis rate. miR-222-3p affects OSCC cell proliferation, migration, invasion, and apoptosis through targeting CDKN1B, and may be a potential prognostic biomarker for OSCC patients.

Long non-coding RNA BANCR promotes proliferation and migration in oral squamous cell carcinoma via MAPK signaling pathway.

Long non-coding RNAs (lncRNAs) have been shown to be aberrantly expressed in oral squamous cell carcinoma (OSCC), but the biological role and function of BRAF-activated long non-coding RNA (BANCR) in OSCC remain poorly understood. In this study, we found that the expression of BANCR was upregulated in OSCC tissues and cell lines compared to the negative control. The decreased expression of BANCR in vitro markedly inhibited OSCC cell proliferation, migration, and invasion while the opposite was observed for the overexpression of BANCR. The results also showed that the expression of MAPK signaling-related proteins (p-erk, p-akt, and p-p-38) was positively correlated with that of BANCR. Thus, BANCR may play an important role in the tumorigenesis of OSCC, as well as cell proliferation, migration, and invasion of OSCC, and it may be a potential therapeutic target and prognostic factor in OSCC patients.

Long Noncoding RNA RC3H2 Facilitates Cell Proliferation and Invasion by Targeting MicroRNA-101-3p/EZH2 Axis in OSCC

In our previous studies, enhancer of zeste homolog 2 (EZH2) has been proven to be a key oncogenic driver in oral squamous cell carcinoma (OSCC). However, the regulatory mechanisms on EZH2 remain poorly understood in OSCC. Here, through multi-transcriptomics, bioinformatics analysis, and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), the co-expression network of long noncoding RNA RC3H2 (RC3H2), microRNA-101-3p (miR-101-3p), and EZH2 were screened and validated as a competing endogenous RNA (ceRNA) mechanism in OSCC. Silencing of RC3H2 inhibited OSCC cell proliferation, colony formation, migration, and invasion in vitro and reduced the expression of EZH2 and H3K27Me3, whereas RC3H2 overexpression significantly promoted OSCC cell growth, colony formation, migration, invasion, and xenograft tumor growth in vivo and increased the expression of EZH2 and H3K27Me3. A fluorescence in situ hybridization (FISH) assay verified that RC3H2 was predominately localized to the cytoplasm. RNA pull-down and luciferase activity assays showed that miR-101-3p was physically bound to RC3H2 as well as EZH2, and its inhibitor reversed the inhibitory effect of RC3H2 knockdown on progression of OSCC. Taken together, our findings demonstrate that RC3H2 as completive endogenous RNA sponging miR-101-3p targets EZH2 and facilitates OSCC cells’ malignant behavior.

Vitamin D inhibits the proliferation of Oral Squamous Cell Carcinoma by suppressing lncRNA LUCAT1 through the MAPK pathway.

Background: Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer worldwide. Recent studies have suggested that vitamin D (VitD) is associated with a reduced risk of many chronic illnesses, including cancer. However, the role of vitamin D in OSCC has rarely been reported.Materials and Methods: The effect of vitamin D and control treatment were examined by cell clone formation assay. Using RNA-seq, we globally identified VitD-regulated long noncoding RNAs (lncRNAs). The expression of LUCAT1 in OSCC tissues and cell lines was examined by qRT-PCR. The correlation between LUCAT1 expression level and clinicopathological characteristics was analyzed. The biological roles of LUCAT1 in OSCC cell proliferation was determined by CCK8 and cell colony formation. The role of LUCAT1 in OSCC growth was further confirmed by mouse xenograft tumor model. Combined with the literature, the mechanism of action of LUICAT1 was verified by western blot.Results: In this study, we observed that VitD inhibited tumour cell growth in OSCC. We found that lncRNA LUCAT1 was downregulated by VitD and served as an important mediator of VitD in inhibiting OSCC cell proliferation. Moreover, we observed that the expression of LUCAT1 was significantly upregulated in OSCC tissues compared to non-tumour tissues. We further demonstrated that LUCAT1 promoted the proliferation of oral cancer cells by enhancing the activation of the mitogen protein kinase (MAPK) signalling pathway.Conclusion: In summary, our results show that VitD inhibited the growth of OSCC cells through the LUCAT1-MAPK signalling pathway. Our study suggested that VitD could suppress the progression of oral cancer, and LUCAT1 may be a potential tumour marker for the diagnosis and prognosis of OSCC.

GAS5, a FoxO1-actived long noncoding RNA, promotes propofol-induced oral squamous cell carcinoma apoptosis by regulating the miR-1297-GSK3β axis

Propofol, an intravenous anaesthetic agent, has been found to exhibit antitumour effects in various kinds of cancer cells. However, the potential roles and regulatory mechanisms of propofol in oral squamous cell carcinoma (OSCC) remain unknown. Herein, we found that propofol inhibits OSCC cell growth and promotes cell apoptosis in a dose- and time-dependent manner. Further mechanistic studies revealed that the long noncoding RNA GAS5 is induced by propofol in OSCC cells. Elevated GAS5 acts as a competing endogenous RNA for miR-1297 and attenuates its inhibitory effect on GSK3β, leading to GSK3β increase and Mcl1 decrease. Additionally, we found that FoxO1 binds to the promoter of GAS5, facilitating its transcription in response to propofol treatment. Thus, these results suggest that propofol exhibits antitumour effects in OSCC cells and that the FoxO1-GAS5-miR-1297-GSK3β axis plays an important role in propofol-induced OSCC cell apoptosis.

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.

Identification of AUNIP as a candidate diagnostic and prognostic biomarker for oral squamous cell carcinoma.

BackgroundOral squamous cell carcinoma (OSCC) is one of the most common malignant tumors worldwide. Patients with poorly differentiated OSCC often exhibit a poor prognosis. AUNIP (Aurora Kinase A and Ninein Interacting Protein), also known as AIBp, plays a key role in cell cycle and DNA damage repair. However, the function of AUNIP in OSCC remains elusive.MethodsThe differentially expressed genes (DEGs) were obtained using R language. Receiver operating characteristic curve analysis was performed to identify diagnostic markers for OSCC. The effectiveness of AUNIP in diagnosing OSCC was evaluated by machine learning. AUNIP expression was analyzed in publicly available databases and clinical specimens. Bioinformatics analysis and in vitro experiments were conducted to explore biological functions and prognostic value of AUNIP in OSCC.FindingsThe gene integration analysis revealed 90 upregulated DEGs. One candidate biomarker, AUNIP, for the diagnosis of OSCC was detected, and its expression gradually increased along with malignant differentiation of OSCC. Bioinformatics analysis demonstrated that AUNIP could be associated with tumor microenvironment, human papillomavirus infection, and cell cycle in OSCC. The suppression of AUNIP inhibited OSCC cell proliferation and resulted in G0/G1 phase arrest in OSCC cells. The survival analysis showed that AUNIP overexpression predicted poor prognosis of OSCC patients.Interpretation: AUNIP could serve as a candidate diagnostic and prognostic biomarker for OSCC and suppression of AUNIP may be a potential approach to preventing and treating OSCC.FundTaishan Scholars Project in Shandong Province (ts201511106) and the National Natural Science Foundation of China (Nos. 61603218).

Long noncoding RNA OIP5-AS1 promotes the progression of oral squamous cell carcinoma via regulating miR-338-3p/NRP1 axis

Opa-interacting protein 5 antisense RNA 1 (OIP5-AS1), a novel identified long noncoding RNA (lncRNA), has been suggested to serve as oncogene in multiple cancers. However, the functional involvement of OIP5-AS1 in oral squamous cell carcinoma (OSCC) was still unknown. The aims of this study were to investigate the functional role of OIP5-AS1 in OSCC and explore its potential mechanism. We found that OIP5-AS1 was up-regulated in OSCC tissues compared with adjacent non-tumor tissues. Loss-of-function experiments revealed that OIP5-AS1 knockdown significantly inhibited OSCC cell proliferation, migration and invasion in vitro, and retarded tumor growth in vivo. Mechanistically, OIP5-AS1 serves as a competing endogenous RNA of miR-338-3p and modulates the expression of neuropilin1 (NRP1), which has been identified as a downstream target gene of miR-338-3p in OSCC. Moreover, downregulation of miR-338-3p or overexpression of NRP1 partly reversed the inhibitory effect of OIP5-AS1 depletion on cell proliferation, migration and invasion. The current results provide evidences for the role of OIP5-AS1 in promoting OSCC progression by regulating miR-338-3p/NRP1 axis and suggest OIP5-AS1 as a potential therapy target for OSCC.

Circ-PKD2 inhibits carcinogenesis via the miR-204-3p/APC2 axis in oral squamous cell carcinoma.

Recent findings have shown that dysregulation of circular RNAs (circRNAs) is implicated in various cancers. However, the contribution of circRNAs in oral squamous cell carcinoma (OSCC) remains largely unexplored. We screened circRNA expression profiles using a circRNA microarray in paired OSCC and normal tissues and explored the clinical significance of a downregulated circRNA, circ-PKD2. Moreover, the biological function of circ-PKD2 in OSCC was investigated both in vitro and in vivo. We found that downregulation of circ-PKD2 in OSCC correlated significantly with aggressive characteristics. Further analysis revealed that overexpression of circ-PKD2 inhibited OSCC cell proliferation, migration and invasion, induced apoptosis and cell cycle arrest, which were promoted by knockdown of circ-PKD2. In addition, circ-PKD2 was identified as a sponge for miR-204-3p and upregulated the expression of adenomatous polyposis coli 2 (APC2), which was the functional target of miR-204-3p. Moreover, circ-PKD2 attenuated the oncogenic effects of miR-204-3p-mediated APC2 on OSCC progression via multiple signaling pathways. These results demonstrate that the circ-PKD2/miR-204-3p/APC2 axis represents a novel pathway involved in the pathogenesis of OSCC and may serve as a novel therapeutic target of OSCC.

MicroRNA-224, negatively regulated by c-jun, inhibits growth and epithelial-to-mesenchymal transition phenotype via targeting ADAM17 in oral squamous cell carcinoma.

Abnormal expression of miR‐224 has been reported to promote cancer progression. However, the role of miR‐224 is seldom reported in oral squamous cell carcinoma (OSCC). We reported that miR‐224 expression was significantly down‐regulated in OSCC tissues and cell lines. Restoration of miR‐224 decreased OSCC cell growth and invasion. In addition, luciferase and Western blot assays revealed that ADAM17 protein was a downstream target of miR‐224. The overexpression of ADAM17 dismissed miR‐224’s effect on cell growth and invasion. We concluded that miR‐224 inhibited OSCC cell growth and invasion through regulating ADAM17 expression. Subsequently, we revealed that c‐jun directly bind to miR‐224 promoter and decreased miR‐224 expression. Taken together, these findings demonstrated that miR‐224 may function as a tumour‐suppressive microRNA in OSCC and suggested that miR‐224 may be a potential therapeutic target for OSCC patients.

Identification of AUNIP as a Candidate Diagnostic and Prognostic Biomarker for Oral Squamous Cell Carcinoma

Background: Oral squamous cell carcinoma (OSCC) is one of the most common malignant tumors worldwide. Patients with poorly differentiated OSCC often have a poor prognosis. It is essential to search for promising diagnostic and prognostic biomarkers for OSCC. Methods: The differentially expressed genes (DEGs) were obtained using R language. Receiver operating characteristic curve analysis was performed to identify diagnostic markers for OSCC. AUNIP expression was analyzed in publicly available databases and clinical specimens. Bioinformatics analysis and in vitro experiments were conducted to explore biological functions and prognostic value of AUNIP in OSCC. Findings: The gene integration analysis revealed 90 upregulated DEGs. One candidate biomarker, AUNIP, for the diagnosis of OSCC was detected. Weighted gene co-expression network analysis and function enrichment analysis demonstrated that genes positively associated with AUNIP were enriched in cell cycle and the module eigengene was significantly correlated with the survival rate of OSCC patients. In gene set enrichment analysis, the correlation between AUNIP expression and human papillomavirus status in OSCC was verified. The suppression of AUNIP inhibited OSCC cell proliferation and resulted in G0/G1 phase arrest in OSCC cells. The survival analysis showed that AUNIP overexpression interrelated with the poor prognosis of OSCC patients. Interpretation: AUNIP could serve as a candidate diagnostic and prognostic biomarker for OSCC and suppression of AUNIP may be a potential approach to prevent and treat OSCC. Funding Statement: Taishan Scholars Project in Shandong Province (ts201511106) and the National Natural Science Foundation of China (Nos. 61603218). Declaration of Interests: The authors declare no conflicts of interest. Ethics Approval Statement: The samples were approved by Taizhou hospital Ethics Committee in Zhejiang province.

MiRNA-10a promotes cancer cell proliferation in oral squamous cell carcinoma by upregulating GLUT1 and promoting glucose metabolism.

MicroRNA-10a (miRNA-10a) promotes lung cancer; however, to the best of our knowledge, its involvement in other cancer types is unknown. The present study aimed to investigate the role of miRNA-10a in oral cancer. Expression levels of miRNA-10a and glucose transporter 1 (GLUT1) in tumor tissues and adjacent healthy tissues obtained from patients with oral squamous cell carcinoma (OSCC) were detected by reverse transcription-quantitative polymerase chain reaction. Correlation analysis between the expression levels of miRNA-10a and GLUT1 was performed using Pearson's correlation coefficient. It was identified that miRNA-10a and GLUT1 were upregulated in tumor tissues compared with adjacent healthy tissues of patients with OSCC. Expression levels of miRNA-10a and GLUT1 were positively correlated in tumor tissues but not in adjacent healthy tissues. In addition, miRNA-10a overexpression promoted glucose uptake and upregulated GLUT1 in OSCC cells. Furthermore, GLUT1 overexpression promoted glucose uptake; however, no significant increase in the expression level of miRNA-10a in OSCC cells was detected. Overexpression of miRNA-10a and GLUT1 promoted OSCC cell proliferation, while GLUT1-knockdown inhibited OSCC cell proliferation. GLUT1-knockdown also attenuated the enhancing effect of miRNA-10a overexpression on cancer cell proliferation. Therefore, miRNA-10a may promote cancer cell proliferation in OSCC by upregulating GLUT1 and promoting glucose metabolism.

The serum biomarker chemerin promotes tumorigenesis and metastasis in oral squamous cell carcinoma.

Chemerin, which is encoded by retinoic acid receptor responder 2 (RARRES2), has been found to be related to malignant tumours, but its role in the development of oral squamous cell carcinoma (OSCC) is largely unexplored. In the present study, a higher serum level of chemerin was evident in patients with OSCC than in healthy individuals, and this high level of chemerin significantly decreased after tumour resection. In addition, high chemerin levels were positively associated with advanced tumour stage and lymph node metastasis. The expression levels of chemerin and Chemerin Receptor 23 (ChemR23) were positively correlated with the migration and invasion of OSCC cell lines. Recombinant chemerin (R-chemerin) enhanced the in vitro migration, invasion and proliferation of OSCC cells in a concentration-dependent manner, and short hairpin RNAs (shRNAs) targeting RARRES2 decreased chemerin expression and inhibited OSCC cell metastasis and proliferation both in vitro and in vivo Additionally, R-chemerin activated manganese superoxide dismutase (SOD2) and increased the amount of intracellular hydrogen peroxide (H2O2), leading to a significant decrease in E-cadherin expression and dramatic increase in the expression of phosphorylated ERK1/2 (p-ERK1/2), Slug, Vimentin and N-cadherin, but shRNAs targeting RARRES2 reversed these effects. Moreover, knockdown of ChemR23 with small interfering RNAs (siRNA) significantly inhibited chemerin-induced OSCC cell migration/invasion and SOD2 activity. Our results revealed that chemerin is a novel biomarker for OSCC. Chemerin/ChemR23 promotes tumorigenesis and metastasis in OSCC and may be a new therapeutic target for OSCC.