Effect of different approaches of direct radiation on the surface structure and caries susceptibility of enamel.

It is not clear whether different radiation methods have different effects on enamel. The purpose of this study was to compare the effects of single and fractionated radiation on enamel and caries susceptibility and to provide an experimental basis for further study of radiation­related caries. Thirty-six caries-free human third molars were collected and randomly divided into three groups (n = 12). Group1 (control group) was not exposed to radiation. Group 2 received single radiation with a cumulative dose of 70 Gy. Group 3 underwent fractionated radiation, receiving 2 Gy/day for 5 days followed by a 2-day rest period, for a total of 7 weeks with a cumulative dose of 70 Gy. Changes in microhardness, roughness, surface morphology, bacterial adhesion and ability of acid resistance of each group were tested. Scanning electron microscope revealed that the enamel surface in both radiation groups exhibited unevenness and cracks. Compared with the control group, microhardness and acid resistance of enamel decreased, while roughness and bacterial adhesion increased in both the single radiation and fractionated radiation groups. Compared with the single radiation group, the enamel surface microhardness and acid resistance decreased in the fractionated radiation group, while roughness and bacterial adhesion increased. Both single radiation and fractionated radiation resulting in changes in the physical and biological properties of enamel, with these changes being more pronounced in the fractionated radiation group. Therefore, fractionated radiation is recommended as a more suitable method for constructing a radiation­related caries model in vitro.

WNT3 promotes chemoresistance to 5-Fluorouracil in oral squamous cell carcinoma via activating the canonical ß-catenin pathway.

BACKGROUND: 5-Fluorouracil (5FU) is a primary chemotherapeutic agent used to treat oral squamous cell carcinoma (OSCC). However, the development of drug resistance has significantly limited its clinical application. Therefore, there is an urgent need to determine the mechanisms underlying drug resistance and identify effective targets. In recent years, the Wingless and Int-1 (WNT) signaling pathway has been increasingly studied in cancer drug resistance; however, the role of WNT3, a ligand of the canonical WNT signaling pathway, in OSCC 5FU-resistance is not clear. This study delved into this potential connection. METHODS: 5FU-resistant cell lines were established by gradually elevating the drug concentration in the culture medium. Differential gene expressions between parental and resistant cells underwent RNA sequencing analysis, which was then substantiated via Real-time quantitative PCR (RT-qPCR) and western blot tests. The influence of the WNT signaling on OSCC chemoresistance was ascertained through WNT3 knockdown or overexpression. The WNT inhibitor methyl 3-benzoate (MSAB) was probed for its capacity to boost 5FU efficacy. RESULTS: In this study, the WNT/ß-catenin signaling pathway was notably activated in 5FU-resistant OSCC cell lines, which was confirmed through transcriptome sequencing analysis, RT-qPCR, and western blot verification. Additionally, the key ligand responsible for pathway activation, WNT3, was identified. By knocking down WNT3 in resistant cells or overexpressing WNT3 in parental cells, we found that WNT3 promoted 5FU-resistance in OSCC. In addition, the WNT inhibitor MSAB reversed 5FU-resistance in OSCC cells. CONCLUSIONS: These data underscored the activation of the WNT/ß-catenin signaling pathway in resistant cells and identified the promoting effect of WNT3 upregulation on 5FU-resistance in oral squamous carcinoma. This may provide a new therapeutic strategy for reversing 5FU-resistance in OSCC cells.

IL-8 activates fibroblasts to promote the invasion of HNSCC cells via STAT3-MMP1.

Matrix metalloproteinase-1 (MMP1) has an aberrant expression relevant to various behaviors of cancers. As dominant components of the tumor stroma, fibroblasts constitute an important source of Matrix metalloproteinase (MMPs) including mainly MMP1. The impacts of MMP1 derived from fibroblasts in tumor microenvironment, however, is not well defined. In this study, we demonstrated a part of crosstalk between fibroblasts and cancer cells that enhanced the invasiveness of cancer cells, IL8-induced activation of STAT3 signaling pathway as a key promoter to elevated MMP1 level in fibroblasts that supports the migration and invasion of head and neck squamous cell carcinoma (HNSCC) cells by extracellular matrix degradation. Importantly, once exposed to the inhibitor of STAT3 phosphorylation (TPCA-1), the enhanced induction of HNSCC cells invasion triggered by fibroblasts was significantly impaired.

The comparative safety of human papillomavirus vaccines: A Bayesian network meta-analysis.

BACKGROUND AND AIMS: The safety of human papillomavirus (HPV) vaccines, one of the major challenges to public vaccination, has been controversial. This study assessed the adverse reactions of various HPV vaccines, including bivalent HPV (2vHPV), quadrivalent HPV (4vHPV), and 9-valent HPV (9vHPV) vaccines. METHODS: PubMed, Embase, and Central databases were searched for randomized controlled trials (RCTs) on the comparative safety of HPV vaccines. A network meta-analysis was performed based on the Bayesian framework random-effects model. RESULTS: This study included 23 RCTs. Analysis across these reports indicated that the 2vHPV vaccine was associated with significantly more systemic adverse events than the 4vHPV vaccine (risk ratio [RR]: 1.28, 95% credible interval [CrI]: 1.14-1.44), 9vHPV vaccine (RR: 1.25, 95% CrI: 1.06-1.49), and placebo (RR: 1.31, 95% CrI: 1.18-1.46). However, there were no statistically significant differences in serious adverse events between the vaccinated and placebo groups. For injection-site adverse events, there were substantial inconsistencies between the direct and indirect effects; therefore, the analysis results of the safety were presented only for systemic and serious adverse events. CONCLUSIONS: The 2vHPV vaccine resulted in more systemic adverse events than other vaccines and placebo. No significant differences in serious adverse events were observed. Further studies are needed to obtain more information regarding the safety of HPV vaccines.

EGCG inhibits growth of tumoral lesions on lip and tongue of K-Ras transgenic mice through the Notch pathway.

Epigallocatechin-3-gallate (EGCG), the main active ingredient of green tea, exhibits low toxic side effect and versatile bioactivities, and its anti-cancer effect has been extensively studied. Most of the studies used cancer cell lines and xenograft models. However, whether EGCG can prevent tumor onset after cancer-associated mutations occur is still controversial. In the present study, Krt14-cre/ERT-Kras transgenic mice were developed and the expression of K-RasG12D was induced by tamoxifen. Two weeks after induction, the K-Ras mutant mice developed exophytic tumoral lesions on the lips and tongues, with significant activation of Notch signaling pathway. Administration of EGCG effectively delayed the time of appearance, decreased the size and weight of tumoral lesions, relieved heterotypic hyperplasia of tumoral lesions, and prolonged the life of the mice. The Notch signaling pathway was significantly inhibited by EGCG in the tumoral lesions. Furthermore, EGCG significantly induced cell apoptosis and inhibited the proliferation of tongue cancer cells by blocking the activation of Notch signaling pathway. Taken together, these results indicate EGCG as an effective chemotherapeutic agent for tongue cancer by targeting Notch pathway.

High expression of Notch2 drives tongue squamous cell carcinoma carcinogenesis.

Tongue squamous cell carcinoma (TSCC) is one of the most common cancers in the oral cavity. Notch signaling is frequently dysregulated in cancer. However, the role of Notch2 in TSCC is not well understood. The aim of this study was to investigate the effect of abnormal expression of Notch2 in TSCC. The expression of Notch2 was tested in 47 pairs of tissues from tongue cancer and normal samples by using immunohistochemical staining. Tongue cancer cells were transfected with siRNA or plasmid. The proliferation of the cells was tested by the CCK8 assay and colony formation assay. Subcutaneous tumor model was established to observe tumor growth. Transwell assay was used to detect the changes of cell migration and invasion ability. A humanized anti-Notch2 antibody was used to TSCC cells. We found that Notch2 was upregulated in tongue carcinoma tissues. Knocking down the expression of Notch2 by siRNA in the TSCC cell lines decreased proliferation ability both in vitro and in vivo. In addition, migration and invasion abilities were inhibited by knockdown of Notch2 in the TSCC cells. However, overexpression of Notch2 increased tongue cancer cell proliferation, invasion and migration. The humanized anti-Notch2 antibody inhibited TSCC cell growth. The results indicated that Notch2 is an oncogene in tongue squamous cell carcinoma and may become the target of a new approach for treating TSCC.

The NOTCH1-HEY1 pathway regulates self-renewal and epithelial-mesenchymal transition of salivary adenoid cystic carcinoma cells.

Our previous study demonstrated a close relationship between the NOTCH signaling pathway and salivary adenoid cystic carcinoma (SACC). Its receptor gene, NOTCH1, and its downstream gene, HES1, contribute to the proliferation, invasion and metastasis of SACC. Accumulating evidence supports HEY1 as another effector of the signaling pathway. The purpose of this study was to explore the effects of the NOTCH1-HEY1 pathway on the proliferation, invasion and metastasis of SACC cells. Our results verified that HEY1 is a specific molecular target of the NOTCH signaling pathway in SACC cells and that its expression in carcinoma is much higher than that in paracarcinoma tissues. The expression of NOTCH1 and HEY1 are positively correlated in the salivary adenoid cystic carcinoma tissues. NOTCH1 is significantly related to the activation of HEY1 in SACC, and that HEY1 reciprocally regulates NOTCH1 expression in SACC. HEY1 promotes cell proliferation and spheroid formation and inhibits cell apoptosis in vitro. In addition, HEY1 enhances the tumorigenicity of SACC in vivo. Furthermore, HEY1 increases cell invasion and metastasis by driving the expression of epithelial-mesenchymal transition (EMT)-related genes and MMPs. The results of this study indicate that the NOTCH1-HEY1 pathway is specifically upregulated in SACC and promotes cell proliferation, self-renewal, invasion, metastasis and the expression of EMT-related genes and MMPs. Our findings suggest that a NOTCH1-HEY1 pathway inhibitor might therefore have potential therapeutic applications in treating SACC patients by inhibiting cancer cell growth and metastasis.

Elevated matrix metalloproteinase 7 expression promotes the proliferation, motility and metastasis of tongue squamous cell carcinoma.

BACKGROUND: Matrix metalloproteinase 7 (MMP7), as the smallest member of the matrix metalloproteinase family, has been verified to be implicated in cancer progression, especially metastasis. However, its expression pattern and function in tongue cancer is not clear. METHODS: The expression of MMP7 in human tongue squamous cell carcinoma (TSCC) specimens compared with their respective paired nontumour tissues by real-time PCR and immunohistochemical staining. The effect of MMP7 on the proliferation, apoptosis, migration, invasion of tongue cancer cells was tested in appropriate ways after MMP7 siRNA knockdown or overexpression. The effect of MMP7 on lymph node metastasis in vivo was analyzed using a high-metastasis orthotopic nude mouse tongue transplanted tumour model. RESULTS: We found markedly elevated expression of MMP7 in human TSCC specimens compared with their respective paired nontumour tissues, and this high expression was correlated with the patients' lymph node metastasis. Furthermore, the results of molecular functional assays confirmed that MMP7 promotes cell proliferation, migration and invasion of TSCC cells. Knockdown of MMP7 inhibited lymph nodes metastasis in vivo. CONCLUSIONS: MMP7 plays an oncogenic role in carcinogenesis and metastasis of tongue cancer, and may serve as a potential therapeutic target for tongue cancer.

Synergistic inhibition of lung cancer cells by EGCG and NF-κB inhibitor BAY11-7082.

Lung cancer has a poor 5-year survival rate and is the leading cause of cancer-related deaths worldwide. Thus, the development of more efficient therapeutic strategies is urgently needed. Many studies have shown that EGCG, a major polyphenol found in green tea, has potential anticancer effects. The present study aims to investigate the molecular mechanism of EGCG-mediated inhibition of proliferation in lung cancer cells and to explore the effects of combined treatment with EGCG and an NF-κB inhibitor, BAY11-7082, in A549 and H1299 cells both in vitro and in vivo. Our results showed that EGCG inhibits cell proliferation and migration and induces apoptosis in A549 and H1299 cells at relatively high concentrations (IC50=86.4 µM for A549 cells and 80.6 µM for H1299 cells). These effects are partially achieved via inhibition of the NF-κB signaling pathway. Combined treatment with EGCG and BAY11-7082, a potent NF-κB inhibitor, shows significant synergistic effects at relatively low concentrations. The inhibition rate reached approximately 50% in cells treated for 72 h with 20 µM EGCG and 5 µM (A549 cells) or 2.5 µM BAY11-7082 (H1299 cells). This synergistic anti-tumor effect was also observed in a xenograft model. These results indicated that EGCG inhibits lung cancer cell proliferation by suppressing NF-κB signaling. Coadministration of EGCG and BAY11-7082 has a synergistic effect both in vitro and in vivo and may serve as a novel therapeutic strategy for lung cancer.

FLI-06 Intercepts Notch Signaling And Suppresses The Proliferation And Self-renewal Of Tongue Cancer Cells.

PURPOSE: The Notch signaling pathway plays an oncogenic role in tongue squamous cell carcinoma. The aim of this study was to inhibit the proliferation and self-renewal of tongue cancer cells by applying Notch signaling pathway inhibitor FLI-06 (Selleck, USA) and to lay a foundation for the clinically targeted treatment of tongue cancer for the future. METHODS: The mRNA expression level of Notch1 and the overall survival rate of patients with tongue cancer were examined by analyzing the TCGA database. Tongue cancer cells were treated with FLI-06. Cell proliferation, apoptosis, and stem cell self-renewal ability were tested in appropriate ways. A xenograft mouse model was established to observe tumor growth. RESULTS: From the TCGA data, we demonstrated that patients with high expression of Notch1 had a poor prognosis. We observed that the Notch signaling pathway inhibitor FLI-06 can restrain the activation of the Notch signaling pathway, decrease cell proliferation and induce cell apoptosis in vitro. The xenograft experiment indicated that intraperitoneal injection of FLI-06 inhibited tumor growth and increased cell apoptosis. FLI-06 suppressed both the mRNA and protein expression of Notch receptor and Notch targeted genes. We also observed that FLI-06 suppressed the proliferation of tongue cancer stem cells. CONCLUSION: FLI-06 can block the proliferation and self-renewal of tongue cancer cells. It is inferred that this compound, which inhibits the Notch signaling pathway, may serve as a potential targeted drug for the treatment of tongue cancer in the clinic.

FZD2 regulates cell proliferation and invasion in tongue squamous cell carcinoma.

Many studies have shown that FZD2 is significantly associated with tumor development and tumor metastasis. The purpose of the present study was to gain insight into the role of FZD2 in the cell proliferation and invasion of tongue squamous cell carcinoma. According to TCGA-HNSC dataset, among the 10 Frizzled receptors, FZD2 exhibited the highest degree of differential expression between cancer tissues and normal tissues, and the overall survival of patients with higher FZD2 levels was shown to be significantly shorter compared with those with lower FZD2 levels. The upregulation of FZD2 in clinical tongue cancer tissues was validated by real-time PCR. Knockdown of FZD2 inhibited the proliferation, migration and invasion of CAL-27 and TCA-8113 cells, whereas overexpression of FZD2 led to the opposite results. Further analysis revealed that FZD2 is positively correlated with WNT3A, WNT5B, WNT7A and WNT2 and is negatively correlated with WNT4. These results indicated that FZD2 may act as an oncogene in tongue squamous cell carcinoma. Therefore, FZD2 may be a target for the diagnosis, prognosis and gene therapy of tongue cancer.

The oncogenic effects of HES1 on salivary adenoid cystic carcinoma cell growth and metastasis.

BACKGROUND: Our previous study demonstrated a close relationship between NOTCH signaling pathway and salivary adenoid cystic carcinoma (SACC). HES1 is a well-known target gene of NOTCH signaling pathway. The purpose of the present study was to further explore the molecular mechanism of HES1 in SACC. METHODS: Comparative transcriptome analyses by RNA-Sequencing (RNA-Seq) were employed to reveal NOTCH1 downstream gene in SACC cells. Immunohistochemical staining was used to detect the expression of HES1 in clinical samples. After HES1-siRNA transfected into SACC LM cells, the cell proliferation and cell apoptosis were tested by suitable methods; animal model was established to detect the change of growth ability of tumor. Transwell and wound healing assays were used to evaluate cell metastasis and invasion. RESULTS: We found that HES1 was strongly linked to NOTCH signaling pathway in SACC cells. The immunohistochemical results implied the high expression of HES1 in cancerous tissues. The growth of SACC LM cells transfected with HES1-siRNAs was significantly suppressed in vitro and tumorigenicity in vivo by inducing cell apoptosis. After HES1 expression was silenced, the SACC LM cell metastasis and invasion ability was suppressed. CONCLUSIONS: The results of this study demonstrate that HES1 is a specific downstream gene of NOTCH1 and that it contributes to SACC proliferation, apoptosis and metastasis. Our findings serve as evidence indicating that HES1 may be useful as a clinical target in the treatment of SACC.

Notch1 regulates tongue cancer cells proliferation, apoptosis and invasion.

OBJECTIVES: Notch1 regulates tumor biology in a complex, context-dependent manner. The roles of Notch1 in tongue cancer are still controversial. The aim of this study is to investigate the roles of Notch1 in tongue cancer. MATERIALS AND METHODS: The expression of Notch1 was tested between tongue cancer and normal samples by using immunohistochemistry. Tongue cancer cells were transfected with siRNA or plasmid, respectively. Cell proliferation, apoptosis, migration and invasion ability were tested in appropriate ways. The subcutaneous tumor model was established to observe the tumor growth. RESULTS: Notch1 was upregulated in tongue carcinoma tissues and the expression of Notch1 was related with tumor stage and differentiation. Overexpression of Notch1 could increase tongue cancer cells proliferation, invasion and migration. But inhibited the expression of Notch1 could decrease cells proliferation, invasion and migration and promote cell apoptosis in vitro and in vivo. CONCLUSION: Our results prove that the oncogenic role of Notch1 in tongue cancer and provide the direction of targeted therapy of tongue cancer.

ID1 contributes to cell growth invasion and migration in salivary adenoid cystic carcinoma.

Previous studies have reported that inhibitor of DNA binding 1 (ID1) exerts an oncogenic role in a number of tumors. In the present study, the role of ID1 in the growth, invasion and migration of salivary adenoid cystic carcinoma (SACC) cells was investigated. ID1 expression in clinical SACC samples was compared with that in normal salivary tissues using immunohistochemical staining, and the correlation between ID1 expression and clinical pathological characteristics was then determined. Subsequently, ID1 was overexpressed or silenced to investigate the effects of ID1 expression on SACC cell proliferation, invasion and migration. In addition, the gene expression levels of known ID1 target genes, including S100A9, CDKN2A and matrix metalloproteinase 1 (MMP1) was measured using reverse transcription­quantitative polymerase chain reaction to elucidate the potential mechanisms of ID1 in SACC. The results of the present study indicated that the protein expression levels of ID1 were significantly increased in the SACC tissues compared with that in the normal salivary tissues (P<0.001), and a positive correlation between ID1 expression and tumor stage (P=0.001), tumor invasion (P=0.002) and metastasis (P=0.019) in SACC was observed. Knockdown of ID1 in SACC cells significantly inhibited cell growth, invasion and migration (all P<0.01), whereas overexpression of ID1 promoted cell proliferation, invasion and migration (all P<0.01). The gene expression level of MMP1 was significantly reduced following ID1 knockdown in SACC­83 cells when compared with negative controls (P<0.05), whereas S100A9 and CDKN2A expression levels were significantly upregulated (both P<0.05). The results suggest that ID1 may regulate the growth, invasion and migration of SACC cells, and that MMP1, S100A9 and CDKN2A may serve as target genes of ID1 and mediate the effects of ID1 in SACC cells. Therefore, ID1 may present a potential target gene for the treatment of patients with SACC to inhibit cancer cell growth and metastasis.

CDH4 suppresses the progression of salivary adenoid cystic carcinoma via E-cadherin co-expression.

The cadherin-4 gene (CDH4) of the cadherin family encodes non-epithelial R-cadherin (R-cad); however, the function of this gene in different types of cancer remains controversial. In this study, we found higher expression of CDH4 mRNA in a salivary adenoid cystic carcinoma (SACC) cell line with low metastatic potential (SACC-83) than in a cell line with high metastatic potential (SACC-LM). By analyzing 67 samples of SACC tissues and 40 samples of paraneoplastic normal tissues, we found R-cad highly expressed in 100% of normal paraneoplastic tissue but only expressed in 64% of SACC tumor tissues (P<0.001). Knockdown of CDH4 expression in vitro promoted the growth, mobility and invasion of SACC cells, and in vivo experiments showed that decreased CDH4 expression enhanced SACC tumorigenicity. Furthermore, CDH4 suppression resulted in down-regulation of E-cadherin (E-cad), which is encoded by CDH1 gene and is a well-known tumor suppressor gene by inhibition of cell proliferation and migration. These results indicate that CDH4 may play a negative role in the growth and metastasis of SACC via co-expression with E-cadherin.

Notch2 signaling contributes to cell growth, invasion, and migration in salivary adenoid cystic carcinoma.

Many studies have explored whether the Notch signaling pathway has a tumor-suppressive or an oncogenic role in various tumors; however, the role of the Notch signaling pathway in salivary adenoid cystic carcinoma (SACC) is still unknown. In this study, we attempt to define the role of Notch2 signaling in cell growth, invasion, and migration in SACC. We compared Notch2 expression in clinical SACC samples with that of normal samples by using immunohistochemical staining. Then, we down-regulated Notch2 expression to observe the effect of Notch2 on proliferation, invasion, migration, and the expression of known target genes of Notch signal pathway. According to our results, Notch2 expression was higher in SACC tissues compared with normal tissues. Knockdown of Notch2 inhibited cell proliferation, invasion, and migration in vitro and down-regulated the expression of HEY2 and CCND1. The results of this study suggest that Notch2 has an essential role in the cell growth, invasion, and migration of SACC. Notch2 may therefore be a potential target gene for the treatment of SACC by interfering with cell growth and metastasis.