Extracellular N6 -isopentenyladenosine (i6A) addition induces cotranscriptional i6A incorporation into ribosomal RNAs.

N6 -isopentenyladenosine (i6A), a modified adenosine monomer, is known to induce cell death upon its addition to the culture medium. However, the molecular fate of extracellularly added i6A has yet to be identified. Here we show that i6A addition to cell culture medium results in i6A incorporation into cellular RNA in several cell lines, including the 5-fluorouracil (5-FU)-resistant human oral squamous cell carcinoma cell line FR2-SAS and its parental 5-FU-sensitive cell line SAS. i6A was predominantly incorporated into 18S and 28S rRNAs, and i6A incorporation into total RNA was mostly suppressed by treating these cell lines with an RNA polymerase I (Pol I) inhibitor. i6A was incorporated into RNA even upon inactivation of TRIT1, the only cellular i6A-modifying enzyme. These results indicate that upon cellular uptake of i6A, it is anabolized to be used for Pol I transcription. Interestingly, at lower i6A concentrations, the cytotoxic effect of i6A was substantially more pronounced in FR2-SAS cells than in SAS cells. Moreover, in FR2-SAS cells, i6A treatment decreased the rate of cellular protein synthesis and increased intracellular protein aggregation, and these effects were more pronounced than in SAS cells. Our work provides insights into the molecular fate of extracellularly applied i6A in the context of intracellular nucleic acid anabolism and suggests investigation of i6A as a candidate for a chemotherapy agent against 5-FU-resistant cancer cells.

FOXM1-Mediated Regulation of Reactive Oxygen Species and Radioresistance in Oral Squamous Cell Carcinoma Cells.

Radioresistance is a major obstacle to the successful treatment of oral squamous cell carcinoma (OSCC). To help overcome this issue, we have developed clinically relevant radioresistant (CRR) cell lines generated by irradiating parental cells over time, which are useful for OSCC research. In the present study, we conducted gene expression analysis using CRR cells and their parental lines to investigate the regulation of radioresistance in OSCC cells. Based on gene expression changes over time in CRR cells and parental lines subjected to irradiation, forkhead box M1 (FOXM1) was selected for further analysis in terms of its expression in OSCC cell lines, including CRR cell lines and clinical specimens. We suppressed or upregulated the expression of FOXM1 in OSCC cell lines, including CRR cell lines, and examined radiosensitivity, DNA damage, and cell viability under various conditions. The molecular network regulating radiotolerance was also investigated, especially the redox pathway, and the radiosensitizing effect of FOXM1 inhibitors was examined as a potential therapeutic application. We found that FOXM1 was not expressed in normal human keratinocytes but was expressed in several OSCC cell lines. The expression of FOXM1 was upregulated in CRR cells compared with that detected in the parental cell lines. In a xenograft model and clinical specimens, FOXM1 expression was upregulated in cells that survived irradiation. FOXM1-specific small interfering RNA (siRNA) treatment increased radiosensitivity, whereas FOXM1 overexpression decreased radiosensitivity, and DNA damage was altered significantly under both conditions, as well as the levels of redox-related molecules and reactive oxygen species production. Treatment with the FOXM1 inhibitor thiostrepton had a radiosensitizing effect and overcame radiotolerance in CRR cells. According to these results, the FOXM1-mediated regulation of reactive oxygen species could be a novel therapeutic target for the treatment of radioresistant OSCC; thus, treatment strategies targeting this axis might overcome radioresistance in this disease.

The antioxidative stress regulator Nrf2 potentiates radioresistance of oral squamous cell carcinoma accompanied with metabolic modulation.

Nuclear factor erythroid 2-related factor 2 (Nrf2), which regulates the expression of critical antioxidant proteins, was recently demonstrated to play a key role in cancer progression. Resistance to radiotherapy is a major obstacle in treating oral squamous cell carcinoma (OSCC). However, little is known about the association between Nrf2 and radioresistance in OSCC. Two OSCC cell lines (SAS and HSC-2) and their clinically relevant radioresistant (CRR) clones (SAS-R, HSC-2-R) were used. The effects of Nrf2 downregulation on radiosensitivity and the involvement of glycolysis in Nrf2-mediated radioresistance were evaluated. Immunohistochemistry of phosphorylated Nrf2 (p-Nrf2) was performed in 110 patients with OSCC who underwent preoperative chemoradiotherapy and surgery. Nrf2 was stably upregulated in CRR cells in vitro and in a mouse xenograft model. Moreover, elevated Nrf2 expression was associated with radioresistance. The enhancement of Nrf2-dependent glycolysis and glutathione synthesis was involved in the development of radioresistance. Additionally, p-Nrf2 expression was closely related to the pathological response to chemoradiotherapy, and its expression was predictive of prognosis in patients with advanced OSCC. Our results suggest that Nrf2 plays an important role in the radioresistance of OSCC accompanied by metabolic reprogramming. Targeting Nrf2 antioxidant pathway may represent a promising treatment strategy for highly malignant OSCC.

Naringenin potentiates anti-tumor immunity against oral cancer by inducing lymph node CD169-positive macrophage activation and cytotoxic T cell infiltration.

The CD169+ macrophages in lymph nodes are implicated in cytotoxic T lymphocyte (CTL) activation and are associated with improved prognosis in several malignancies. Here, we investigated the significance of CD169+ macrophages in oral squamous cell carcinoma (OSCC). Further, we tested the anti-tumor effects of naringenin, which has been previously shown to activate CD169+ macrophages, in a murine OSCC model. Immunohistochemical analysis for CD169 and CD8 was performed on lymph node and primary tumor specimens from 89 patients with OSCC. We also evaluated the effects of naringenin on two murine OSCC models. Increased CD169+ macrophage counts in the regional lymph nodes correlated with favorable prognosis and CD8+ cell counts within tumor sites. Additionally, naringenin suppressed tumor growth in two murine OSCC models. The mRNA levels of CD169, interleukin (IL)-12, and C-X-C motif chemokine ligand 10 (CXCL10) in lymph nodes and CTL infiltration in tumors significantly increased following naringenin administration in tumor-bearing mice. These results suggest that CD169+ macrophages in lymph nodes are involved in T cell-mediated anti-tumor immunity and could be a prognostic marker for patients with OSCC. Moreover, naringenin is a new potential agent for CD169+ macrophage activation in OSCC treatment.

Air Plasma-Activated Medium Evokes a Death-Associated Perinuclear Mitochondrial Clustering.

Intractable cancers such as osteosarcoma (OS) and oral cancer (OC) are highly refractory, recurrent, and metastatic once developed, and their prognosis is still disappointing. Tumor-targeted therapy, which eliminates cancers effectively and safely, is the current clinical choice. Since aggressive tumors are substantially resistant to multidisciplinary therapies that target apoptosis, tumor-specific activation of another cell death modality is a promising avenue for meeting this goal. Here, we report that a cold atmospheric air plasma-activated medium (APAM) can kill OS and OC by causing a unique mitochondrial clustering. This event was named monopolar perinuclear mitochondrial clustering (MPMC) based on its characteristic unipolar mitochondrial perinuclear accumulation. The APAM caused apoptotic and nonapoptotic cell death. The APAM increased mitochondrial ROS (mROS) and cell death, and the antioxidants such as N-acetylcysteine (NAC) prevented them. MPMC occurred following mitochondrial fragmentation, which coincided with nuclear damages. MPMC was accompanied by mitochondrial lipid peroxide (mLPO) accumulation and prevented by NAC, Ferrostatin-1, and Nocodazole. In contrast, the APAM induced minimal cell death, mROS generation, mLPO accumulation, and MPMC in fibroblasts. These results suggest that MPMC occurs in a tumor-specific manner via mitochondrial oxidative stress and microtubule-driven mitochondrial motility. MPMC induction might serve as a promising target for exerting tumor-specific cytotoxicity.

Role of serum amylase and salivary cytokines in oral complications during chemoradiotherapy.

OBJECTIVES: To investigate whether serum amylase can predict the recovery of salivary volume and determine the correlation of the level of cytokines, including epidermal growth factor, hepatocyte growth factor and keratinocyte growth factor, with oral mucositis during chemoradiotherapy for oral cancer. SUBJECTS AND METHODS: This study included 84 patients treated with preoperative chemoradiotherapy followed by curative surgery, following a phase II study protocol. We measured and analysed the correlation of the stimulated saliva volume, serum amylase and cytokines in resting saliva at baseline and 1 month after chemoradiotherapy with oral mucositis levels. RESULTS: We observed a negative correlation between the serum amylase level at the beginning of chemoradiotherapy and the stimulated saliva volume at 1 month after chemoradiotherapy (p = .03). Epidermal growth factor in resting saliva was significantly reduced after chemoradiotherapy (p < .01). The incidence of severe oral mucositis during chemoradiotherapy was significantly higher and negatively associated with the epidermal growth factor and keratinocyte growth factor levels (p = .04, p = .05). CONCLUSIONS: The serum amylase level at the beginning of chemoradiotherapy may be a predictor of the recovery of the saliva volume. Furthermore, cytokines such as epidermal growth factor and keratinocyte growth factor in resting saliva affect the development of oral mucositis during chemoradiotherapy.

BRD4 promotes metastatic potential in oral squamous cell carcinoma through the epigenetic regulation of the MMP2 gene.

BACKGROUND: Oral squamous cell carcinoma (OSCC) has increased morbidity, and its high metastatic potential affects patient survival. Bromodomain containing 4 (BRD4) is a chromatin protein that associates with acetylated histone lysines and facilitates transcription. BRD4 has been implicated in cell proliferation, metastasis, and prognosis in several types of cancer. However, the role of BRD4 in OSCC remains to be elucidated. METHODS: We investigated the role of BRD4 and its potential utility as a therapeutic target in OSCC. RESULTS: JQ1, the BRD4 inhibitor, suppressed the cell proliferation, migration, and invasion in the OSCC cell lines and in vivo. JQ1 reduced the expression levels of 15 metastasis genes in OSCC, including matrix metallopeptidase 2 (MMP2). Our chromatin immunoprecipitation assay showed that JQ1 reduced the BRD4 binding to the histone H3 lysine 27 acetylation-enriched sites in the MMP2 locus. Analyses of biopsy specimens from OSCC patients revealed that the BRD4 and MMP2 expression levels were correlated in the cancerous regions, and both were highly expressed in lymph node metastasis cases, including delayed metastasis. CONCLUSIONS: BRD4 contributes to metastasis in OSCC, through the epigenetic regulation of the MMP2 gene, and thus BRD4 may represent a therapeutic target and a novel prediction indicator for metastasis.

Circulating miRNA-1290 as a potential biomarker for response to chemoradiotherapy and prognosis of patients with advanced oral squamous cell carcinoma: A single-center retrospective study.

MicroRNAs are a class of small, endogenous, noncoding 18- to 24-nucleotide-long RNAs that can regulate multiple processes related to cancer progression. However, their clinical value in patients with oral squamous cell carcinoma has not yet been fully explored. Therefore, the aim of this study was to investigate the clinical significance of circulating microRNAs in oral squamous cell carcinoma patients. The expression levels of circulating miR-1246 and miR-1290 in healthy volunteers and oral squamous cell carcinoma patients were examined by quantitative real-time polymerase chain reaction. The expression levels of both microRNAs in the radioresistant oral squamous cell carcinoma cell line (SAS-R) and the parent cell line (SAS) and in the conditioned medium obtained from these cell lines were also examined by quantitative real-time polymerase chain reaction. In addition, the correlations between circulating microRNA status and various clinicopathological features in 55 oral squamous cell carcinoma patients with locally advanced oral squamous cell carcinoma who underwent surgery following 5-fluorouracil-based chemoradiotherapy were examined. The expression level of miR-1290 was significantly lower in the plasma of oral squamous cell carcinoma patients than in that of healthy volunteers (p < 0.01). The expression levels of microRNAs in the conditioned medium and in the cells varied from cell to cell. In the clinicopathological analyses, the frequency of patients with low miR-1290 levels was significantly higher among cases with lower pathological differentiation and among those with a poor pathological response for preoperative chemoradiotherapy (p = 0.030 each). Furthermore, Cox regression analysis based on the 5-year overall survival and disease-free survival revealed that miR-1290 status was a significant prognostic factor for patients with oral squamous cell carcinoma (hazard ratio = 0.169, p = 0.008, and hazard ratio = 0.186, p = 0.008, respectively). Circulating miR-1290 status could be a valuable biomarker for predicting the clinical response to chemoradiotherapy as well as overall survival in patients with oral squamous cell carcinoma.

HMGA2 Contributes to Distant Metastasis and Poor Prognosis by Promoting Angiogenesis in Oral Squamous Cell Carcinoma.

The highly malignant phenotype of oral squamous cell carcinoma (OSCC), including the presence of nodal and distant metastasis, reduces patient survival. High-mobility group A protein 2 (HMGA2) is a non-histone chromatin factor that is involved in advanced malignant phenotypes and poor prognosis in several human cancers. However, its biological role in OSCC remains to be elucidated. The purpose of this study was to determine the clinical significance and role of HMGA2 in the malignant potential of OSCC. We first investigated the expression pattern of HMGA2 and its clinical relevance in 110 OSCC specimens using immunohistochemical staining. In addition, we examined the effects HMGA2 on the regulation of vascular endothelial growth factor (VEGF)-A, VEGF-C, and fibroblast growth factor (FGF)-2, which are related to angiogenesis, in vitro. High expression of HMGA2 was significantly correlated with distant metastasis and poor prognosis. Further, HMGA2 depletion in OSCC cells reduced the expression of angiogenesis genes. In OSCC tissues with high HMGA2 expression, angiogenesis genes were increased and a high proportion of blood vessels was observed. These findings suggest that HMGA2 plays a significant role in the regulation of angiogenesis and might be a potential biomarker to predict distant metastasis and prognosis in OSCC.

FBXW7 expression affects the response to chemoradiotherapy and overall survival among patients with oral squamous cell carcinoma: A single-center retrospective study.

FBXW7 (F-box and WD repeat domain containing-7) is a tumor suppressor protein that regulates the degradation of various oncoproteins in several malignancies. However, limited information is available regarding FBXW7 expression in oral squamous cell carcinoma. Therefore, this study aimed to determine the clinical significance of FBXW7 expression in oral squamous cell carcinoma. The FBXW7 expression patterns in oral squamous cell carcinoma and adjacent normal tissues from 15 patients who underwent radical resection were evaluated using quantitative real-time polymerase chain reaction and immunohistochemical staining. In addition, immunohistochemistry was performed using paraffin-embedded sections from biopsy specimens obtained from 110 patients with oral squamous cell carcinoma who underwent surgery after 5 fluorouracil-based chemoradiotherapy. The associations of FBXW7 expression with various clinicopathological features and prognosis were evaluated in these patients. As a results, in the 15 matched samples, the FBXW7 expression was significantly decreased in the oral squamous cell carcinoma tissues compared to that in the adjacent normal tissues. In the clinicopathological analysis, compared to high protein expression, low FBXW7 expression was found to significantly associate with a poor histological response to preoperative chemoradiotherapy. Kaplan-Meier curve analysis revealed that low FBXW7 expression was significantly associated with a poor prognosis, and FBXW7 expression was found to be an independent predictor of overall survival in the multivariate analysis. Our results suggest that FBXW7 may function as a tumor suppressor protein in oral squamous cell carcinoma. In addition, FBXW7 could be a potential biomarker for predicting not only the clinical response to chemoradiotherapy but also overall survival in patients with oral squamous cell carcinoma.

IL-6 controls resistance to radiation by suppressing oxidative stress via the Nrf2-antioxidant pathway in oral squamous cell carcinoma.

BACKGROUND: In promoting tumour malignancy IL-6 signalling is considered to have an important role. However, the biological roles of IL-6 on radiosensitivity in oral squamous cell carcinoma (OSCC) remain largely unclear. The objective of this study is to determine the effects and molecular mechanisms of IL-6 on radiosensitivity in OSCC. METHODS: Two OSCC cell lines, and OSCC tissue samples with radioresistant cells were used. We examined the effects of IL-6, or tocilizumab, a humanised anti-human IL-6 receptor antibody, or both on radiosensitivity and DNA damage after X-ray irradiation in vitro. In addition, we investigated the involvement of the Nrf2-antioxidant pathway in IL-6-mediated radioresistant mechanisms using OSCC cell lines and tissues. RESULTS: Increased levels of IL-6 suppressed radiation-induced cell death, and the blockade of IL-6 signalling by tocilizumab sensitised tumour cells to radiation. The radioresistant effect of IL-6 was associated with decreased DNA damage after radiation. We also found that IL-6 promotes the activation of not only the downstream molecule STAT3 but also the Nrf2-antioxidant pathway, leading to a significant decrease in oxidative stress by upregulating Mn-SOD. CONCLUSIONS: These results indicate that the blockade of IL-6 signalling combined with conventional radiotherapy could augment the treatment response and survival rate in patients with radioresistant OSCC.

Pre-treatment neutrophil to lymphocyte ratio predicts the chemoradiotherapy outcome and survival in patients with oral squamous cell carcinoma: a retrospective study.

BACKGROUND: The Neutrophil to lymphocyte ratio (NLR) has prognostic value in patients with a variety of cancers. However, its prognostic significance in oral squamous cell carcinoma (OSCC) patients has not been fully explored. The purpose of this study was to determine the clinical significance of NLR in patients with OSCC. METHODS: OSCC patients who underwent surgery following 5-fluorouracil (5-FU)-based chemoradiotherapy were enrolled in this study. The associations between the NLR status and various clinicopathological features were examined, and the effects of the NLR on the prognosis were evaluated. Analysis of circulating interleukin-6 (IL-6) was carried out and correlation with NLR and C-reactive protein concentration (CRP) was examined. RESULTS: An elevated NLR was significantly correlated with advanced T-stage and poor response to chemoradiotherapy. Moreover, a Cox regression analysis based on the disease-free survival (DFS) revealed the NLR status (hazard ratio, 2.013; P = 0.041) and pathological response to chemoradiotherapy (hazard ratio, 0.226; P = 0.001) to be significant prognostic factors in OSCC patients. Furthermore, circulating IL-6 was found to correlate with NLR and CRP. CONCLUSION: The NLR is a potential biomarker for predicting the clinical response to 5-FU-based chemoradiotherapy and the survival in OSCC patients, and the systemic inflammatory response may be potential target for improving patient's prognosis.

A low Dicer expression is associated with resistance to 5-FU-based chemoradiotherapy and a shorter overall survival in patients with oral squamous cell carcinoma.

BACKGROUND: The deregulation of microRNA (miRNA) is associated with multiple processes involved in cancer progression. RNase III endonucleases, Dicer and Drosha, are key enzymes for miRNA biogenesis, and it has been reported that altered expressions of these molecules affect the clinical outcomes of patients with various cancers. However, the clinical value of measuring the levels of Dicer and Drosha in oral squamous cell carcinoma (OSCC) patients is unclear. The purpose of this study was to determine the clinical significance of the expressions of Dicer and Drosha in patients with OSCC. METHODS: Oral squamous cell carcinoma specimens were obtained from 61 patients who underwent surgery following 5-fluorouracil-based chemoradiotherapy at Kumamoto University Hospital between October 2003 and January 2009. Paraffin-embedded sections obtained from biopsy specimens were immunohistochemically analyzed. The associations between Dicer, Drosha, and various clinicopathological features were examined, and the effects of Dicer and Drosha on the prognosis were evaluated. RESULTS: A low Dicer tumor expression was significantly correlated with the pathological response to chemoradiotherapy. Furthermore, a Cox regression analysis based on the overall survival revealed the Dicer expression status (hazard ratio, 0.34; P = 0.048) and pathological response to chemoradiotherapy (hazard ratio, 0.21; P = 0.014) to be significant prognostic factors in OSCC patients. On the other hand, the Drosha expression was not associated with any clinicopathological features or the prognosis. CONCLUSION: These results suggest that Dicer is a potential biomarker for predicting the clinical response to 5-FU-based chemoradiotherapy and the overall survival in patients with OSCC.

Selective inhibition of nuclear factor-κB by nuclear factor-κB essential modulator-binding domain peptide suppresses the metastasis of highly metastatic oral squamous cell carcinoma.

Nuclear factor-κB (NF-κB) activation contributes to the development of metastasis, thus leading to a poor prognosis in many cancers, including OSCC. However, little in vivo experimental data are available about the effects of NF-κB inhibition on OSCC metastasis. OSCC sublines were established from a GFP-expressing parental cell line, GSAS, and designated GSAS/N3 and N5 according to the in vivo passage number after cervical lymph node metastasis by a serial orthotopic transplantation model. In vitro migration and invasion were assessed in these cells, and the NF-κB activities and expression of NF-κB-regulated metastasis-related molecules were also examined. In in vivo experiments, the metastasis and survival of tumor-engrafted mice were monitored. Furthermore, the effects of a selective NF-κB inhibitor, NEMO-binding domain (NBD) peptide, on metastasis in GSAS/N5-engrafted mice were assessed, and engrafted tongue tumors were immunohistochemically examined. Highly metastatic GSAS/N3 and N5 cells showed an enhanced NF-κB activity, thus contributing to increased migration, invasion, and a poor prognosis compared with the parent cells. Furthermore, the expression levels of NF-κB-regulated metastasis-related molecules, such as fibronectin, ß1 integrin, MMP-1, -2, -9, and -14, and VEGF-C, were upregulated in the highly metastatic cells. The NBD peptide suppressed metastasis and tongue tumor growth in GSAS/N5-inoculated mice, and was accompanied by the downregulation of the NF-κB-regulated metastasis-related molecules in engrafted tongue tumors. Our results suggest that the selective inhibition of NF-κB activation by NBD peptide may provide an effective approach for the treatment of highly metastatic OSCC.

Laterality on FDG-PET/CT in clinically node-negative early-stage oral squamous cell carcinoma: a retrospective analysis of patients with late neck metastasis.

This study aimed to assess the role of preoperative 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) for predicting late neck metastasis in clinically node-negative (cN0) early-stage oral squamous cell carcinoma (OSCC). We retrospectively investigated the standardized uptake value (SUV) parameters in patients with late neck metastasis based on the neck node level. The study population consisted of 16 patients with cT1N0 or cT2N0 oral SCC who were evaluated with dual-phase FDG-PET/CT and were treated with local resection of the primary tumor and watchful waiting for neck management. The SUV at each level was measured on the early and delayed images, and the laterality of the SUV was calculated. The laterality on the delayed images significantly differed between positive and negative pairs at the levels Ib (p = 0.002) and IIb (p = 0.013); a cut-off value of 1.4 yielded a true-positive rate of 50% and a false-positive rate of 6%. The laterality of FDG-uptake should be used to stratify the risk for nodal-level metastasis.

An oncolytic virus as a promising candidate for the treatment of radioresistant oral squamous cell carcinoma.

We evaluated the usefulness of an oncolytic virus (Suratadenoturev; OBP-301) against radioresistant oral squamous cell carcinoma. We confirmed the expression of human telomerase reverse transcriptase and the coxsackievirus and adenovirus receptor in cell lines. Also, we examined the potential presence in a patient who has received existing therapy that is amenable to treatment with OBP-301. We evaluated: (1) the antitumor effects of OBP-301 alone and in combination with radiotherapy on radioresistant cell lines, (2) the molecular mechanism underlying the radiosensitizing effect and cell death increased by the combination therapy, and (3) the antitumor effect of the combination therapy in vivo using xenograft models (a radioresistant cell line-derived xenograft in mouse and a patient-derived xenograft). Human telomerase reverse transcriptase and the coxsackievirus and adenovirus receptor were expressed in all cell lines. OBP-301 decreased the proliferative activity of these cell lines in a concentration-dependent manner, and significantly enhanced the antitumor effect of irradiation. Phosphorylated STAT3 and its downstream molecules, which correlated with apoptosis and autophagy, showed significant changes in expression after treatment with OBP-301. The combination therapy exerted a significant antitumor effect versus radiotherapy alone in both xenograft models. Combination of OBP-301 with radiotherapy exerts a synergistic effect and may represent a promising treatment for radioresistant oral squamous cell carcinoma.

Can MRI-derived depth of invasion predict nodal recurrence in oral tongue cancer?

OBJECTIVES: To evaluate the prognostic value of preoperative radiological findings for nodal recurrence in clinically node-negative (cN0) patients with oral tongue squamous cell carcinoma (SCC). METHODS: The study population consisted of 52 patients with cT1-2N0 oral tongue SCC classified according to the 7th edition of the Union for International Cancer Control (UICC) staging system. The subjects had undergone preoperative radiological examinations, including magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography. All patients were treated with local resection and watchful waiting for neck management. Using an unpaired t test, Pearson's chi-squared test, and the Kaplan-Meier method, the MRI-derived depth of invasion (DOI), the standardized uptake value (SUV) on FDG-PET, and the T stage according to the 7th and 8th UICC were assessed as prognostic factors. RESULTS: The MRI-derived DOI was recorded as ≤ 5 mm in 24 patients and > 5 mm in 28 patients. During the follow-up period, nine patients exhibited nodal recurrence, with the MRI-derived DOI being significantly higher in patients with positive than in those with negative (p = 0.011). The SUV was not significant. Five-year cumulative nodal recurrence probabilities were 4.5% for patients with an MRI-derived DOI ≤ 5 mm, while it was 32.1% for > 5 mm (p = 0.013). Although the T classifications were not significant, none of our patients whose T stage according to the 8th UICC was T1 suffered nodal recurrence. CONCLUSIONS: MRI-derived DOI can predict nodal recurrence, while preoperative information may assist in treatment planning for oral tongue SCC.

miR-30a attenuates drug sensitivity to 5-FU by modulating cell proliferation possibly by downregulating cyclin E2 in oral squamous cell carcinoma.

We aimed to determine the functional role of the miRNA, which affects drug sensitivity to 5-FU in oral squamous cell carcinoma (OSCC), using two types of 5-FU-resistant and parental OSCC cell lines. MiRNA microarray data showed that miR-30a was significantly upregulated in two resistant cell lines. Therefore, we investigated the effects and molecular mechanism of miR-30a on 5-FU sensitivity. Stable overexpression of miR-30a in parental OSCC cells decreased cell proliferation and attenuated drug sensitivity to 5-FU. Cell cycle analysis indicated that miR-30a overexpression increased the proportion of G1 phase cells and decreased the proportion of S phase cells. MiR-30a knockdown using siRNA reversed the effects of miR-30a overexpression. DNA microarray analysis using miR-30a-overexpressing cell lines and a TargetScan database search showed that cyclin E2 (CCNE2) is a target of miR-30a. A luciferase reporter assay confirmed that a miR-30a mimic interacted with the specific binding site in the 3' UTR of CCNE2. CCNE2 knockdown with siRNA in OSCC cells yielded decreased drug sensitivity to 5-FU, similar to miR-30a overexpressing cells. These findings suggest that miR-30a in OSCC may be a novel biomarker of 5-FU-resistant tumors, as well as a therapeutic target for combating resistance.

Re-evaluating the clinical significance of serum p53 antibody levels in patients with oral cancer in Japanese clinical practice.

TP53 gene mutations can lead to mutant p53 protein accumulation in cancer cells, thereby inducing the production of serum antip53 antibodies (Ap53Ab) in patients with various types of cancer. The aim of the present study was to re-evaluate the clinicopathological and prognostic significance of Ap53Ab using the Ap53Ab ELISA kit, approved by the Japanese Health Insurance System in 2007. Ap53Ab was measured as a tumor marker in 94 patients with oral squamous cell carcinoma (OSCC), by subjecting paraffin-embedded sections obtained from biopsy specimens to immunohistochemical analysis to confirm p53 expression. The associations among Ap53Ab status, p53 expression and clinical significance in OSCC were examined. A total of 23% of the patients were Ap53Ab-positive. Ap53Ab status was found to be significantly associated with p53 expression status in primary tumors (P=0.027), clinical T-category, pathological N-category and pathological stage (P=0.04, P=0.010 and P=0.013, respectively). Kaplan-Meier curve analysis revealed that Ap53Ab status was significantly associated with poor disease-free survival (DFS; P=0.043), and Cox regression analysis revealed that Ap53Ab status was a significant prognostic factor for DFS in patients with OSCC (hazard ratio=2.807; 95% confidence interval: 1.029-7.160; P=0.044). These results suggested that Ap53Ab measurement may reflect the p53 mutation status and an aggressive malignant phenotype, and it may serve as a useful predictive marker candidate for OSCC in clinical practice.