Growth Of Oral Cancer Cells Research Articles

Elevated Sad1 and UNC84 Domain Containing 2 (SUN2) level inhibits cell growth and aerobic glycolysis in oral cancer through reducing the expressions of glucose transporter 1 (GLUT1) and lactate dehydrogenase A (LDHA)

Background/purposeOral cancer is a malignant tumor accompanied by high morbidity, mortality, and poor prognosis. Therefore, it is urgent to explore the percise regulation mechanisms underlying oral cancer. Sad1 and UNC84 Domain Containing 2 (SUN2) was considered as a tumor suppressor in some cancers. The purpose of the study was to define the role of SUN2 in oral cancer progression. Materials and methodsTumor tissues and paired paracancerous healthy tissues from 56 oral cancer patients were collected. Cell viability was measured using MTT assay. The colony formation assay was applied to determine cell proliferation ability. The mRNA and protein levels were assessed by qRT-PCR and Western blot, respectively. ResultsSUN2 expression was decreased in oral cancer tissues and cell models. SUN2 overexpression suppressed the growth of oral cancer cells, while the down-regulation of SUN2 promoted cell growth. SUN2 overexpression restrained the glucose uptake, lactate production, and ATP level of oral cancer cells, whereas down-regulation of SUN2 promoted glycolysis. Besides, elevated SUN2 inhibited the glucose transporter 1 (GLUT1) and lactate dehydrogenase A (LDHA) levels. However, SUN2 knockdown increased the levels of GLUT1 and LDHA. ConclusionSUN2 was decreased in oral cancer in vivo and in vitro. SUN2 overexpression suppressed cell growth and glycolysis via reducing the levels of GLUT1 and LDHA in oral cancer.

Suppression of oral cancer by induction of cell cycle arrest and apoptosis using Juniperus communis extract.

The oral cancer incidence rate is slowly increasing and is now the fifth leading cause of cancer-related death due to its high metastasis and recurrence rate. Juniperus communis is used as a traditional Chinese medicine and has been proven to have anti-cancer activity against neuroblastomas. In the present study, we further investigated the anti-cancer mechanisms of J. communis extract (JCo) on oral cancer and evaluated the synergistic effects of JCo combined with 5-fluorouracil (5-FU). We found that JCo inhibited oral cancer cell growth, and that JCo might be less cytotoxic to normal cells than to cancer cells. After JCo treatment, cell cycle arrest was observed at the G0/G1 phase through modulation of p53/p21 and Rb signaling. JCo also caused an increase in the sub-G1 phase and cell apoptosis via the intrinsic and extrinsic apoptosis pathways. JCo combined with 5-FU presented a synergistic effect to reduce cell viability. In conclusion, JCo inhibited oral cancer cell growth by inducing cell cycle arrest and activating cell apoptosis, and JCo significantly synergized with 5-FU. JCo might have the potential to be an adjuvant and a new therapeutic drug for oral cancer treatment.

CCL18-NIR1 promotes oral cancer cell growth and metastasis by activating the JAK2/STAT3 signaling pathway

BackgroundChemokine (C-C motif) ligand 18 (CCL18) affects the malignant progression of varying cancers by activating chemokine receptors. Our previous work has shown that CCL18 promotes hyperplasia and invasiveness of oral cancer cells; however, the cognate receptors of CCL18 involved in the pathogenesis of oral squamous cell carcinoma (OSCC) have not yet been identified. This study aimed to investigate the molecular mechanisms which underlie promotive effects of CCL18 on OSCC progression by binding to functional receptors.MethodsThe expression of CCL18 receptor-NIR1 in OSCC was determined by conducting western blot, immunofluorescence, and immunocytochemistry assays. Chi square test was applied to analyze the relationship between expression levels of NIR1 and clinicopathological variables. Recombinant CCL18 (rCCL18), receptor siRNA and JAK specific inhibitor (AG490) were used in experiments investigating the effects of the CCL18-NIR1 axis on growth of cancer cells (i.e., proliferation, and metastasis), epithelial-mesenchymal transition (EMT) and the activation of the JAK2/STAT3 signaling pathway.ResultsNIR1 as functional receptor of CCL18 in OSCC, was found to be significantly upregulated in OSCC and positively related to the TNM stage of OSCC patients. rCCL18 induced the phenotypical alterations in oral cancer cells including cell growth, metastasis and EMT. The JAK2/STAT3 signaling pathway was confirmed to be a downstream pathway mediating the effects of CCL18 in OSCC. AG490 and knockdown of NIR1 could block the effects of rCCL18-induced OSCC.ConclusionCCL18 can promote the progression of OSCC by binding NIR1, and the CCL18-NIR1 axis can activate JAK2/STAT3 signaling pathway. The identification of the mechanisms underlying CCL18-mediated promotion of OSCC progression could highlight potential therapeutic targets for treating oral cancer.

Nobiletin selectively inhibits oral cancer cell growth by promoting apoptosis and DNA damage in vitro

The aim of this study was to investigate whether nobiletin (NOB) can inhibit the proliferation of oral squamous cell carcinoma (OSCC) cells by promoting apoptosis, oxidative stress (reactive oxygen species [ROS]), and DNA damage. OSCCs were treated with different concentrations of NOB (25, 50, and 100 µM) for different amounts of time (0, 24, 48, and 72 hours). The viability of NOB was assessed by using MTT-based cell viability assays. Flow cytometry was used to assess cell apoptosis, and the expressions of capase-3 and poly (adenosine diphosphate-ribose) polymerase (PARP) were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analyses. The intensity of ROS fluorescence was measured by using a spectrophotometer. The expression of γH2AX and 8-Oxo-20-deoxyguanosine (8-oxodG) were assessed to determine the degree of DNA damage. We observed that NOB decreased OSCC cell viability in a dose- and time-dependent manner but had little effect on primary normal human oral epithelial cells (H0 ECs). Moreover, with the increase in NOB concentration and treatment time, capase-3, PARP messenger RNA (mRNA), and protein levels gradually increased, as did annexin V- and 7 adducin (ADD)-mediated apoptosis. In addition, NOB also increased the levels of ROS and DNA damage in a concentration- and time-dependent manner. NOB can inhibit OSCC cell by promoting apoptosis, ROS production, and DNA damage.

Extract of Juniperus indica Bertol Synergizes with Cisplatin to Inhibit Oral Cancer Cell Growth via Repression of Cell Cycle Progression and Activation of the Caspase Cascade.

Oral cancer—a type of head and neck cancer—is estimated to be the fifth most common cancer in Taiwan. However, efficacious therapies for oral cancer are still lacking due to drug resistance and recurrence. Consequently, the identification of new anticancer agents for clinical treatment is needed. Juniperus indica Bertol is a plant of the Juniperus genus often used as a treatment in traditional medicine due to its anti-inflammatory, antibacterial and diuretic functions. The biofunctions of Juniperus indica Bertol including its anticancer potential, have not been fully explored. As a result, the aim of this research was to investigate the anticancer activity of Juniperus indica Bertol extract (JIB extract) and determine whether JIB extract has synergistic effects with cisplatin in oral cancer. These results are the first to demonstrate that JIB extract exhibits anticancer capacity and synergizes with cisplatin to treat oral cancer. Our findings indicate that JIB extract has a potential to develop anticancer agent and chemo therapeutic adjuvant for oral cancer.

Validation of secreted protein OASEP1 as a prognostic biomarker and therapeutic target for oral cancer.

e18520 Background: Although current treatments for oral cancer (OC) include surgery, radiotherapy, and chemotherapy, their effectiveness is still limited. Therefore, the development of novel prognostic biomarkers and/or therapeutic agents is urgently needed. Methods: Our strategies are as follows: i) Identification of up-regulated genes in cancers by means of gene expression microarray, ii) Validation of clinicopathological significance of their protein expression by tissue microarray, iii) Examination of their growth effect on cancer cells by siRNAs and active ligand protein for growth assays. Results: We selected a secreted protein, OASEP1 (OC-associated serum protein 1) as a candidate. Real-Time qPCR and Western blotting showed that OASEP1 gene and its gene product were expressed in the majority of OC cells. Immunohistochemical staining showed that OASEP1 expression was observed in 73 (74.4%) of 98 OCs that had undergone curative surgery. In addition, high level of OASEP1 expression was associated with poor prognosis for OC patients ( P = 0.0158, by log-rank test). Suppression of OASEP1 expression by siRNAs for OASEP1 (si-OASEP1) significantly suppressed the growth and invasion of OC cell lines. Flowcytometry and live cell imaging showed that si-OASEP1 induced the apoptosis of OC cells. siRNAs against OASEP1-receptor also suppressed the growth of OC cells. Addition of active OASEP1 recombinant protein into culture media enhanced the growth of OC cells probably through AKT pathway. Our data suggest that OASEP1 and its receptor could play a significant role in the growth of OC cells in probable autocrine/paracrine manner. Conclusions: OASEP1 is a possible prognostic biomarker and therapeutic target for OC.

Sulfonyl chromen-4-ones (CHW09) shows an additive effect to inhibit cell growth of X-ray irradiated oral cancer cells, involving apoptosis and ROS generation

Purpose: This study evaluates the growth inhibiting potential of our previously described sulfonyl chromen-4-ones (CHW09) compound in X-ray irradiated oral cancer cells.Materials and methods: The growth inhibiting effect and mechanism of combined CHW09/X-ray treatment was examined by analyzing cell viability, cell cycle, apoptosis, reactive oxygen species (ROS), and DNA damage.Results: Individual treatments of CHW09 (10 μg/mL) and X-ray irradiation (12 Gy) slightly decreased cell viability of oral cancer Ca9-22 (87.25% and 86.54%) and CAL 27 (80.00% and 74.01%) cells and normal oral HGF-1 cells (92.76% and 87.56%) at 24 h-MTS assay, respectively. In a combined treatment (CHW09/X-ray), the cell viability in Ca9-22 and CAL 27 cells was significantly decreased to 73.48% and 59.07%, whereas HGF-1 cells maintained 84.97% viability in 24 h-MTS assay. For CAL 27 cells, both 72 h-MTS assay and clonogenic assay showed that CHW09/X-ray resulted in more growth inhibition than other treatments. Intracellular ROS levels of CHW09/X-ray were higher than for CHW09, X-ray and control. CHW09/X-ray and X-ray alone had higher G2/M arrest than the control and CHW09 alone. Moreover, flow cytometry and western blotting showed that CHW09/X-ray treatment caused higher apoptosis levels. Levels of H2A histone family member X (γH2AX)-based DNA damage and 8-oxo-2′-deoxyguanosine (8-oxodG)-oxidative DNA damage of CHW09/X-ray were higher than for CHW09, X-ray and control.Conclusion: CHW09/X-ray treatment had additive growth inhibiting effects against X-ray irradiated oral cancer cells, partly attributing to apoptosis and ROS generation.

Characterization of OASEP1 as a biomarker and therapeutic target for oral cancer.

e14627 Background: The improved understanding of cancer-specific oncoproteins could lead to the development of new biomarkers or therapeutic strategies for oral cancers. Methods: We conducted this study as follows: i) Identification of up-regulated genes in oral cancers by means of cDNA microarray, ii) Validation of clinicopathological significance of their protein expression by tissue microarray, iii) Examination of the growth on cancer cells by siRNA, iv) Elucidation of their biological effects on tumor growth. Results: We selected a secreted protein, OASEP1 (oral cancer-associated serum protein 1) as a candidate. Immunohistochemical staining showed that OASEP1 protein expression in cytoplasm was observed in 73 (74.4%) of 98 oral cancers that had undergone curative surgery. In addition, high level of OASEP1 expression was associated with poor prognosis for oral cancer patients ( P = 0.0158, by log-rank test). Suppression of OASEP1 expression by siRNA for OASEP1 significantly suppressed the growth of oral cancer cell lines partly through apoptosis as detected by flow cytometric analysis, apoptosis assays, and time lapse imaging. In addition, siRNAs for a candidate receptor of OASEP1 also significantly inhibited its expression and the growth of oral cancer cells, indicating that the functional interaction between OASEP1 and its receptor could regulate the growth of oral cancer cells. Conclusions: Our data suggest that OASEP1 is a possible prognostic biomarker and therapeutic target for oral cancer.

Recapitulation of inflammatory and immune-evasive subtypes of oral cancer cells in immunodeficient mice.

e14199 Background: Prior study stratified Taiwanese oral cancer specimens (n = 40) and cell lines (n = 7) into three distinct molecular subtypes, namely classical (CL), mesenchymal (MS), and basal (BA). In a cell line derived xenograft (CDX) model, we observed MS grew at least 10-fold slower than CL did in immunodeficient mice. By using RNA-seq to portrait the transcriptomes of human tumor and mouse stroma simultaneously, contribution of mouse innate immunity in restricting the growth of human oral cancer cells was assessed. Methods: A half millions of mycoplasma-free OC3 (MS) or TW2.6 (CL) cells with matrigel were subcutaneously implanted into the flank of 10 to 16 weeks old NOG (NOD/SCID/Il2rgtm). RNAs of CDX tissues from OC3-NOG (n = 7) and TW2.6-NOG (n = 5) were extracted and subjected to stranded mRNA sequencing. Clean reads were aligned to GRCh38 (human) and GRCm38 (mouse), respectively, followed by identifying differentially expressed genes and gene set enrichment analysis. Results: Up-regulation of signature genes for dendritic cells and macrophages and enrichment of innate immunity, including Tnfa-Nfkb signaling, interferon alpha response, interferon gamma response and inflammation were detected in OC3- but not in TW2.6-CDXs. These results suggested that OC3 (MS) was more immunogenic than TW2.6 (CL), which is reminiscent of the inflammatory MS (IMS) subtype of head and neck cancer recently described by Keck et al (n = 938, Clin Cancer Res 2015, 21: p870. PMID: 25492084). Conclusions: By RNA-seq/xenome analysis of CDXs, we provide evidence that compared to CL, MS subtype of oral cancer cells elicited a stronger innate immunity in NOG mouse. Alternatively, CL subtype might have evolved as a prototype with superiority in immune escape.

Low C6orf141 Expression is Significantly Associated with a Poor Prognosis in Patients with Oral Cancer

C6orf141 (Chromosome 6 open reading frame 141) is a novel gene, and its role in oral cancer progression remains unclear. C6orf141 expression in oral squamous cell carcinoma (OSCC) and adjacent normal tissues from 428 patients was examined through immunohistochemistry (IHC). Our results revealed that C6orf141 expression was significantly reduced in OSCC compared with adjacent normal tissues. Low C6orf141 expression was significantly associated with a poor American Joint Committee on Cancer pathological stage (P < 0.001), T classification (P = 0.002), and pN stage (P = 0.032). Kaplan–Meier curves revealed that low C6orf141 expression was significantly associated with shorter disease-specific survival (DSS) in patients with OSCC (log-rank P = 0.007). Multivariate analysis indicated that low C6orf141 expression was an independent prognostic biomarker for DSS (adjusted hazard ratio = 1.34; 95% confidence interval = 1.10–1.81; P = 0.05). Additionally, ectopic C6orf141 expression could significantly suppress oral cancer cell proliferation, colony formation, and migratory and invasive abilities. Xenograft tumor growth assay revealed that C6orf141 could significantly suppress oral tumor growth in vivo. Our results suggest that C6orf141 plays a novel tumor-suppressive role in oral cancer cell growth and motility. Furthermore, C6orf141 dysfunction could be a potential prognostic biomarker for OSCC and provide new therapeutic strategies in the future.

Abstract A167: Prevalence of TREG cells and effects of their inhibition on growth of oral cancer cells

Abstract Oral squamous cell carcinoma (OSCC) is one of the major cancers affecting Asian countries. The main causative factor has been tobacco habit. It has been reported that immune dysfunction in these patients is one of the major factors for tumor growth and dissemination that affects disease-free survival of the patients. We assessed the phenotypic and functional characteristics of regulatory T (Treg) CD4+CD25+FoxP3+subsets in patients with OSCC by multicoloured flow cytometry. Subsequently we investigated the effects their inhibition via TDG on growth of OSCC cell lines in vitro. An increased (p&amp;lt;0.05) prevalence of Treg phenotypes (CD4+CD25+, CD4+FoxP3+, CD8+FoxP3+, CD4+CD25+FoxP3+) was observed in the peripheral circulation of OSCC patients that positively correlated with clinicopathologic features. The increased frequency of CD4+CD8+CD25+FoxP3+, a unique T-cell subset, CTLA4+, GITR+, NrP1+ and granzyme B+ (GzmB) Tregs also showed a significantly higher prevalence in OSCC patients. Functionally, CD4+FoxP3+ Tregs showed skewed expression of IL2, IL10 and IL35 in patients as compared with the normal controls. Higher expression of TGFβ in tumor tissues suggests their dominant role in the up regulation of differentiation of Tregs from naive T-cells in the tumor bearing host. Further, enhanced expression of CCR5 and CCR7 on Tregs with up regulation of their ligands (CCL5, CCL19 and CCL21) in tumor cells indicates efficient recruitment and trafficking of Tregs to the tumor site. Treatment with βGBP showed growth-promoting effects on Tregs and oral cancer cells. However, the treatment with its inhibitor TDG resulted in inhibition of Treg subsets and also decreased the frequency of IL10+ and IL35+ Tregs, indicating its immunomodulatory effects. Hence, it seems reasonable to assume that modulation of functional dynamics of selective Treg subsets may be useful in enhancing antitumor immunity and developing immunotherapeutic strategies for patients with oral squamous cell carcinoma. Citation Format: Sadhna Aggarwal, Suresh C. Sharma, Satya N. Das. Prevalence of TREG cells and effects of their inhibition on growth of oral cancer cells [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A167.

Inhibition of microRNA-218 promotes oral squamous cell carcinoma growth by targeting GLUT1 to affect glucose metabolism.

Glucose transporter 1 (GLUT1) is a key player in glucose metabolism that has important roles in oral squamous cell carcinoma (OSCC), while microRNA-218 can target GLUT1 to achieve its biological roles. Therefore, we hypothesize that microRNA-218 may target GLUT1 to participate in OSCC. Tumor tissues and adjacent healthy tissues were collected from OSCC patients, and blood samples were collected from both OSCC patients and healthy controls. Expression of microRNA-218 and GLUT1 in those tissues was detected by qRT-PCR. All patients were followed up for 5 years. Diagnostic and prognostic values of serum microRNA-218 for OSCC were investigated by ROC curve analysis and survival curve analysis, respectively. MicroRNA-218 knockdown OSCC cell lines were established. The effects on cell proliferation, glucose uptake as well as GLUT1 expression were detected by CCK-8 assay, glucose uptake assay and Western blot. MicroRNA-218 expression level was decreased while GLUT1 expression level was increased in tumor tissues compared with adjacent healthy tissues. Serum level of microRNA-218 was lower, while serum level of GLUT1 was higher in cancer patients than that in healthy control. Serum microRNA-218 and GLUT1 can be used to accurately predict OSCC and its prognosis. MicroRNA-218 knockdown promoted tumor cell proliferation, increased glucose uptake and promoted GLUT1 expression. Inhibition of microRNA-218 can promote oral cancer cell growth by targeting GLUT1 to affect glucose metabolism.

Abstract 1919: Characterization of URST1 as a prognostic biomarker and therapeutic target for oral cancer

Abstract Oral cancer shows a high mortality rate, and its incidence is increasing gradually worldwide. Current therapies for oral cancer include surgery, radiotherapy, and chemotherapy, however, local and regional recurrences account for up to 90% of treatment failures after surgery and radiotherapy. Therefore, next generation biomarkers and therapeutic strategies for oral cancer are eagerly awaited. To identify biomarkers and therapeutic targets for oral cancer, we screened genes that overexpressed in the majority of oral cancers by using our original gene expression profile database and identified up-regulated in solid tumor 1 (URST1) as a candidate. Immunohistochemical staining showed that URST1 expression was observed in the majority of oral cancer in 64 of 96 (67%) that had received curative surgery. URST1 expression was associated with poor prognosis for oral cancer patients (P = 0.032 by log-rank test). Reduction of URST1 expression by siRNAs against URST1 (si-URST1) significantly suppressed growth of oral cancer cells. Flow cytometric analysis revealed that si-URST1 increased the population of cancer cells at G2/M. In addition, exposure of cancer cells to selective URST1 inhibitor suppressed the growth of oral cancer cells. These data indicate that URST1 is a possible prognostic biomarker and therapeutic target for oral cancer. Citation Format: Atsushii Takano, Yohei Miyagi, Yataro Daigo. Characterization of URST1 as a prognostic biomarker and therapeutic target for oral cancer [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 1919.

Proteomic analysis of oral cancer reveals new potential therapeutic targets involved in the Warburg effect.

Activation of peroxisome proliferator-activated receptor alpha (PPARα) has been reported to disrupt tumour metabolism and to promote anticancer activity through interfering with the Warburg effect. This study is to investigate whether Warburg effect-related proteins also could be identified in oral tumour lesions and to explore the functional significance of PPARα in metabolic shift. Five pairs of tongue tumour tissues and adjacent reference tissues obtained from 4-NQO/arecoline induced mouse model were analyzed by 2-d-gel-electrophoresis and LC-MS. Further, the hexokinase II level, pyruvate dehydrogenase (PDH) activity, and metabolites of glycolysis and TCA cycle were all examined in order to validate the effect of PPARα on metabolic shift. Changes in protein expression levels revealed that seven proteins, which were involved in glycolysis, the tricarboxylic acid cycle, and the respiratory chain, were down-regulated in tumour tissues. We found that activation of PPARα through fenofibrate could inhibit oral cancer cell growth and switch the way of energy production from the Warburg effect to oxidative phosphorylation. Fenofibrate induced a reduction of hexokinase II protein levels, increases in PDH activity and metabolites of the TCA cycle, and an impairment of ATP production. These findings suggested that activation of the PPARα to reprogram the metabolic pathway might impair the Warburg effect and trigger cancer cell death. The study provides a novel view of changes in protein expression profiles involved in the Warburg effect during oral tumourigenesis. Activation of the PPARα to impair the Warburg effect might offer a new strategy for oral cancer treatment.

In Vitro Growth of Human Keratinocytes and Oral Cancer Cells into Microtissues: An Aerosol-Based Microencapsulation Technique.

Cells encapsulation is a micro-technology widely applied in cell and tissue research, tissue transplantation, and regenerative medicine. In this paper, we proposed a growth of microtissue model for the human keratinocytes (HaCaT) cell line and an oral squamous cell carcinoma (OSCC) cell line (ORL-48) based on a simple aerosol microencapsulation technique. At an extrusion rate of 20 μL/min and air flow rate of 0.3 L/min programmed in the aerosol system, HaCaT and ORL-48 cells in alginate microcapsules were encapsulated in microcapsules with a diameter ranging from 200 to 300 μm. Both cell lines were successfully grown into microtissues in the microcapsules of alginate within 16 days of culture. The microtissues were characterized by using a live/dead cell viability assay, field emission-scanning electron microscopy (FE-SEM), fluorescence staining, and cell re-plating experiments. The microtissues of both cell types were viable after being extracted from the alginate membrane using alginate lyase. However, the microtissues of HaCaT and ORL-48 demonstrated differences in both nucleus size and morphology. The microtissues with re-associated cells in spheroids are potentially useful as a cell model for pharmacological studies.

Metformin disrupts malignant behavior of oral squamous cell carcinoma via a novel signaling involving Late SV40 factor/Aurora-A

Conventional therapeutic processes in patient with OSCC are associated with several unfavorable effects leading to patients with poor survival rate. Metformin has been shown to protect against a variety of specific diseases, including cancer. However, the precise roles and mechanisms underlying the therapeutic effects of metformin on OSCC remain elusive. In the current study, in vitro and xenograft model experiments revealed that metformin inhibited growth and metastasis of oral cancer cells. Importantly, metformin-restrained tumorigenesis of oral cancer was accompanied with strong decrease of both Aurora-A and Late SV40 Factor (LSF) expressions. Furthermore, LSF contributed to Aurora-A-elicited malignancy behaviors of oral cancer via binding to the promoter region of Aurora-A. A significant correlation was observed between LSF and Aurora-A levels in a cohort of specimens of oral cancer. These findings showed that a novel LSF/Aurora-A-signaling inhibition supports the rationale of using metformin as potential OSCC therapeutics.

Caffeic acid phenethyl ester upregulates N-myc downstream regulated gene 1 via ERK pathway to inhibit human oral cancer cell growth in vitro and in vivo.

Caffeic acid phenethyl ester (CAPE), a bioactive component of propolis, is considered as a new anti-cancer agent. Oral squamous cell carcinoma (OSCC) is the most common oral cancer with unsatisfying survival. N-myc downstream regulated family genes (NDRGs) involve in numerous physiological processes. We investigated the anti-cancer effect of CAPE on OSCC and related mechanisms. Cell proliferation assay, western blot, gene transfection and knockdown, and reporter assay were applied. We showed that CAPE attenuated OSCC cell proliferation and invasion in vitro, and safely and effectively inhibited OSCC cell growth in a xenograft animal model. CAPE treatment induced NDRG1, but not NDRG2 and NDRG3, expression in OSCC cells as determined by western blot, RT-qPCR, and reporter assay. The 5'-deletion assay demonstrated that CAPE increased NDRG1 promoter activity depending on the region of -128 to +46 of the 5'-flanking of NDRG1 gene. NDRG1 gene knockdown attenuated CAPE anti-growth effect on OSCC cells. CAPE activated mitogen-activated protein kinase (MAPK) signaling pathway. The extracellular signal regulated kinase (ERK) inhibitor (PD0325901) and ERK1 knockdown blocked CAPE-induced NDRG1 expression in OSCC cells. CAPE activated MAPK signaling pathway and increased NDRG1 expression through phosphorylation of ERK1/2 to repress OSCC cells growth.

Aberrant DNA hypermethylation-silenced SOX21-AS1 gene expression and its clinical importance in oral cancer.

BackgroundLong noncoding RNAs (lncRNAs) are more than 200 nucleotides in length and lack transcriptional ability. The biological function of lncRNAs in oral squamous cell carcinoma (OSCC) remains unclear. The aim of this study was to identify the dysfunction of lncRNA in OSCC.ResultsWe analyzed the transcriptome profiles of human OSCC tissues and paired adjacent normal tissues from two patients through a next-generation sequencing approach. A total of 14 lncRNAs were upregulated (fold change ≥3) and 13 were downregulated (fold change ≤−3) in OSCC tissues compared with the adjacent normal tissues. SOX21-AS1 was subjected to further analysis, revealing that the expression levels of SOX21-AS1 significantly decreased in OSCC compared with the adjacent normal tissue. The promoter activity of SOX21-AS1 was obviously suppressed by in vitro methylation. The DNA methylation status of the SOX21-AS1 promoter was analyzed using combined bisulfite restriction analysis, revealing that the aberrant promoter hypermethylation of SOX21-AS1 was observed frequently in OSCC tissues. The effects of SOX21-AS1 on cell proliferation and invasion were examined through transient transfection. Our data showed that SOX21-AS1 could significantly suppress oral cancer cell growth and invasion. Furthermore, the low expression level of SOX21-AS1 was significantly correlated with an advanced stage (P = 0.047), large tumor size (P = 0.033), and poor disease-specific survival in OSCC patients (P = 0.002).ConclusionsSOX21-AS1 was identified as susceptible dysfunction correlated with promoter hypermethylation in OSCC. Low SOX21-AS1 expression may be an adverse prognostic biomarker for OSCC.Electronic supplementary materialThe online version of this article (doi:10.1186/s13148-016-0291-5) contains supplementary material, which is available to authorized users.

S100A7 has an oncogenic role in oral squamous cell carcinoma by activating p38/MAPK and RAB2A signaling pathway.

Oral cancer consists of squamous cell carcinoma within the oral cavity or on the lip. The clinical prognosis of this cancer is mostly poor owing to delayed diagnosis and a lack of appropriate early detection biomarkers to identify the disease. In the current study, we investigated the role of the S100A7 calcium-binding protein in oral squamous cell carcinoma as an activator of the p38/MAPK and RAB2A signaling pathway. The aim of the present study was to determine whether S100A7 and RAB2A have a role in tumor progression and to assess their potential as early detection biomarkers for oral cancer. This study elucidated the functional and molecular mechanisms of S100A7 and RAB2A activity in oral cancer, leading us to conclude that S100A7 is the major contributing factor in the occurrence of oral cancer and promotes local tumor progression by activating the MAPK signaling pathway via the RAB2A pathway. We hypothesize that S100A7 affects cell motility and invasion by regulating the RAB2A-associated MAPK signaling cascades. Also, the downregulation of S100A7 expression by RNA interference-mediated silencing inhibits oral cancer cell growth, migration and invasion.

Mesenchymal stem cells derived from normal gingival tissue inhibit the proliferation of oral cancer cells in vitro and in vivo.

The interplay between tumor cells and mesenchymal stem cells (MSCs) within tumor microenvironment plays a significant role in tumor development, and thus might be exploited for therapeutic intervention. In this study, we isolated MSCs from normal gingival tissue (GMSCs), and detected the effect of GMSCs on oral cancer cells via direct co-culture and indirect co-culture systems. The cell proliferation assay of direct co-culture showed that GMSCs could inhibit the growth of oral cancer cells. Conditioned medium derived from GMSCs (GMSCs-CM) also exerted an anticancer effect, which indicates that soluble factors in GMSCs-CM played a dominant role in GMSCs-induced cancer cell growth inhibition. To investigate the mechanism, we performed apoptosis assay by flow cytometry, and confirmed that cancer cell apoptosis induced by GMSCs could be a reason for the effect of GMSCs on the growth of oral cancer cells. Western blotting also confirmed that GMSCs could upregulate expression of pro-apoptotic genes including p-JNK, cleaved PARP, cleaved caspase-3, Bax expression and downregulate proliferation- and anti-apoptosis-related gene expression such as p-ERK1/2, Bcl-2, CDK4, cyclinD1, PCNA and survivin. Importantly, the inhibitory effect of GMSCs on cancer cells can partially be restored by blockade of JNK pathway. Moreover, animal studies showed that GMSCs exerted an anticancer effect after oral cancer cells and GMSCs were co-injected with oral cancer cells. Taken together, our data suggest that GMSCs can suppress oral cancer cell growth in vitro and in vivo via altering the surrounding microenvironment of oral cancer cells, which indicates that GMSCs have a potential use in the management of oral dysplasia and oral cancer in future.