Prognostic significance of NDRG1 expression in oral and oropharyngeal squamous cell carcinoma

Human N-myc downstream-regulated gene 1 (NDRG1) is a metastasis suppressor gene with several potential functions, including cell differentiation, cell cycle regulation and response to hormones, nickel and stress. The purpose of this study was to investigate the immunoexpression of NDRG1 in oral and oropharyngeal squamous cell carcinomas searching for its role in the clinical course of these tumors. We investigated immunohistochemical expression of NDRG1 protein in 412 tissue microarray cores of tumor samples from 103 patients with oral and oropharyngeal squamous cell carcinomas and in 110 paraffin-embedded surgical margin sections. The results showed NDRG1 up-regulation in 101/103 (98.1?%) tumor samples, but no expression in any normal tissue sample. Western blot assays confirmed the immunohistochemical findings, suggesting that lower levels of NDRG1 are associated with a high mortality rate. NDRG1 overexpression was related to long-term specific survival (HR?=?0.38; p?=?0.009), whereas the presence of lymph-node metastasis showed the opposite association with survival (HR?=?2.45; p?=?0.013). Our findings reinforce the idea that NDRG1 plays a metastasis suppressor role in oral and oropharyngeal squamous cell carcinomas and may be a useful marker for these tumors.     

NUMB在口腔白斑和鳞癌中的表达变化及意义

目的:研究NUMB在口腔白斑和鳞癌中的表达及意义。方法:采用免疫组织化学法检测88例口腔正常黏膜、口腔白斑及口腔鳞癌石蜡包埋组织中NUMB蛋白的表达。结果:NUMB在口腔正常黏膜(95.7%)、口腔白斑(75%)及口腔鳞癌(4.7%)中均有阳性表达但是表达频率依次降低。NUMB在各个组中的阳性表达率具有统计学差异(P0.05)。结论NUMB阳性表达率随口腔组织恶性程度增高而减少的趋势提示该基因可能在口腔正常黏膜到口腔白斑再到口腔鳞癌的转化中起作用,NUMB有可能成为早期发现癌变的分子生物学标志之一。     

Evaluation of salivary endothelin-1 levels in oral squamous cell carcinoma and oral leukoplakia

Oral squamous cell carcinoma (OSCC) is the most frequent malignant neoplasia of the oral cavity, which largely compromises the patient's life quality. Therefore, the identification of biomarkers for this kind of cancer is essential to provide a better diagnosis and prognosis for patients. Endothelin-1 is a peptide produced mainly by endothelial cells, and might be found in several body fluids, such as saliva, milk, urine, cerebrospinal fluid and plasma. It has been demonstrated that expression of this peptide is increased in a great number of neoplasias, including oral carcinoma. The identification of salivary biomarkers would be a useful tool for scanning and monitoring patients with risk of developing OSCC, as well to early detect recurrence, or the formation of a new primary tumor. In the present study, we have analyzed the levels of endothelin-1 in saliva obtained from patients with OSCC or oral leukoplakia, in comparison to healthy control patients. This study also evaluated the salivary ET-1 levels in patients with complete remission of OSCC. The results revealed no statistical difference in salivary endothelin-1 levels, neither in OSCC nor in oral leukoplakia, even when conditions such as elderly, sex and hypertension were taken into consideration. Although, ET-1 might display an important role in OSCC, its levels in saliva do not seem to be a good marker of neoplasias grade or malignant transformation.     

NOB1在食管鳞状细胞癌中的表达及临床意义

目的研究NOB1基因在食管鳞状细胞癌（Esophageal squamous cell carcinoma,ESCC）中的表达及临床意义。方法利用免疫组织化学SP法检测59例ESCC及其相应（50例）的远端正常食管黏膜组织中NOB1的表达。结果 ESCC中NOB1的阳性率为71%,正常食管黏膜鳞状上皮中的阳性率为26%,两组比较,差异有统计学意义（P〈0.05）。NOB1的表达与ESCC的分化程度及淋巴结转移相关,与患者的性别,年龄以及肿瘤浸润深度无关。结论 NOB1在ESCC中表达升高,可能在ESCC发生发展过程中起重要作用。     

Cancer stem cell model in oral squamous cell carcinoma

The concept of "field cancerization" describes the presence of histological abnormal tissue surrounding oral squamous cell carcinoma (OSCC). Molecular model of multistep carcinogenesis indicates that an accumulation of genetic alterations forms the basis for the OSCC progression with genetic heterogeneity. Furthermore, we reviewed cancer stem cell (CSC) model, which suggests functional heterogeneity in the tumor mass and current supporting evidence in OSCC. According to CSC model, prevention from carcinogen exposure and eliminating the particular CSCs instead of targeting tumor mass could help obtain a more long-lasting therapeutic effect.     

Deregulation of Beclin 1 in patients with tobacco-related oral squamous cell carcinoma

Autophagy is a physiologically regulated and evolutionary conserved process that plays a critical role in degradation of cytoplasmic proteins and other macromolecules within the lysosomes. Beclin-1, the mammalian orthologue of yeast Atg6, is an important mediator of autophagy that has been studied in many human cancers. However, the expression of Beclin-1 has not yet been investigated in oral cancer. We for the first time investigated the expression of Beclin-1 in serum and tissues and correlated it with the clinic-pathological features of oral cancer patients. m-RNA expression of Beclin-1 was evaluated in tumor and normal areas of surgical specimens from 10 oral cancer patients by real-time PCR. Approximately, 8-fold lower expression (p<0.001) of Beclin-1 mRNA was observed in tumor tissue as compared to the normal tissue. Serum levels of Beclin-1 were evaluated by SPR and ELISA. No significant difference was observed in serum Beclin-1 levels in patients as compared to healthy subjects, similarly no correlation was found between serum levels and clinic-pathological parameters such as stage, lymph node involvement and tumor size. Our results demonstrate that down-regulation of Beclin-1 may play an important role in the development and progression of oral cancer possibly by dysregulation of autophagy in tumor cells.     

Microbial diversity in saliva of oral squamous cell carcinoma

In the oral cavity, chronic inflammation has been observed at various stages of oral squamous cell carcinomas (OSCC). Such inflammation could result from persistent mucosal or epithelial cell colonization by microorganisms. There is increasing evidence of the involvement of oral bacteria in inflammation, warranting further studies on the association of bacteria with the progression of OSCC. The objective of this study was to evaluate the diversity and relative abundance of bacteria in the saliva of subjects with OSCC. Using 454 parallel DNA sequencing, ～58,000 PCR amplicons that span the V4-V5 hypervariable region of rRNAs from five subjects were sequenced. Members of eight phyla (divisions) of bacteria were detected. The majority of classified sequences belonged to the phyla Firmicutes (45%) and Bacteroidetes (25%). Further, 52 different genera containing approximately 860 (16.51%) known species were identified and 1077 (67%) sequences belonging to various uncultured bacteria or unclassified groups. The species diversity estimates obtained with abundance-based coverage estimators and Chao1 were greater than published analyses of other microbial profiles from the oral cavity. Fifteen unique phylotypes were present in all three OSCC subjects.     

Frequent mutations in NOTCH1 ligand-binding regions in Japanese oral squamous cell carcinoma

Recent studies showed that head and neck squamous cell carcinoma (HNSCC) including oral squamous cell carcinoma (OSCC) of Caucasian, Chinese and Indian patients frequently have NOTCH1 mutations. We found eight of 84 OSCC in Japanese patients have point mutations (9.5%) correspond to the ligand binding region of NOTCH1 protein. Two set of them are the same mutations and all mutations are non-synonymous G > A transitions. In addition, median disease-free survival is significantly longer in patients with NOTCH1-mutated tumors as compared to those without the mutation (P < 0.05). The protein structure simulation based on X-ray crystallography indicated that new p.A465T mutation leads to a conformational change of NOTCH1 ligand binding domain as well as the p.G481S mutant NOTCH1 with a loss of flexibility around this residue. These results suggest that NOTCH1 mutation occurs frequently in Japanese OSCC in the vicinity of the ligand binding region and, these mutations cause downregulation of the NOTCH1 function.     

Prognostic significance of TP53 mutations in oral squamous cell carcinoma with human papilloma virus infection

PURPOSE: The aim of this study was to analyze the prognostic impact of mutated TP53 in patients with oral squamous cell carcinoma (OSCC) whose tumors were infected with human papillomavirus (HPV). METHODS: Thirty-two HPV-positive OSCC patients were included. Most of them were clinically classified as stage III (n=29). All patients underwent postoperative radiotherapy (follow-up from 12 to 60 months, median 32). There were 21 relapses. DNA was isolated by phenol extraction from tumor tissue. HPV DNA (type 16, 18, 31, 33) was detected in genomic DNA of the tumors by the PCR-PAGE method. TP53 mutations (exons 4-8) were detected by the PCR-SSCP method. RESULTS: A statistically significant difference in the number of relapses in HPV-infected (13/21) versus HPV-infected and TP53-mutated (8/8) patients was observed. Patients with both TP53 mutation and HPV infection had a significantly shorter disease-free interval than patients with HPV infection only (median 6 versus 31 months, respectively). CONCLUSIONS: TP53 mutations are associated with a higher risk of relapse and contribute to an even worse prognosis of patients with OSCC when the tumors are HPV infected. The shorter disease-free interval in patients with TP53 mutations indicates that the response to postoperative radiotherapy may be influenced by TP53 status. The presence of both HPV infection and TP53 mutations may define a particular group of tumors with a more aggressive phenotype in advanced OSCC.     

Salivary analytes in patients with oral squamous cell carcinoma

Literature data indicates that measurement of certain salivary constituents might serve as a useful diagnostic/prognostic tool in the patients with oral squamous cell carcinoma (OSCC). In 24 patients with OSCC (60 +/- 2.5 yrs) and in 24 controls (24 +/- 3.7 yrs) we have determined levels of salivary magnesium, calcium, copper, chloride, phosphate, potassium, sodium, total proteins and amylase. Sodium, potassium and chloride were determined by indirect potentiometry whereas copper, magnesium and phosphate were determined by atomic absorption spectrophotometry. Total proteins were determined by pyrogalol colorimetric method. Amylase levels were determined by continued colorimetric method. Statistical analysis was performed by use of chi2 test and Spearman's correlation test. The results of this study indicate that the concentrations of sodium and chloride were significantly elevated in patients with OSCC when compared to the controls. However, level of total protein was significantly decreased when compared to the healthy controls. Furthermore, there was a negative correlation between alcohol consumption and total protein concentration in patients with oral carcinoma. We might conclude that in patients with OSCC increased salivary sodium and chloride might reflect their overall dehydration status due to alcohol consumption rather than consequence of OSCC itself.     

Truncated P-cadherin is produced in oral squamous cell carcinoma

Cadherins belong to a family of homophilic cell-cell adhesion proteins that are responsible for the establishment of a precise cell architecture and tissue integrity. Moreover, experimental data suggest that loss of intercellular adhesion is inversely correlated with cellular differentiation. Furthermore, dedifferentiation is closely linked to tumor progression. Recently, we have shown that a secreted 50 kDa N-terminal fragment of P-cadherin plays a role in the progression of malignant melanoma. In this study, we have detected both the full-length and the truncated versions of P-cadherin in cell lysates of differentiated head and neck oral squamous cell carcinoma cell lines, whereas in cell lysates of dedifferentiated cell lines, we detected only the truncated 50 kDa version of P-cadherin. Treatment of the cell lines with a recombinantly expressed biotinylated, soluble 50 kDa form of the N-terminal part of P-cadherin revealed a major effect on cell aggregation and migration of oral squamous cell carcinoma cells. However, the 50 kDa N-terminal fragment of P-cadherin did not show any influence on cell proliferation in 2D and 3D cell culture. These results suggest that generation of truncated P-cadherin during the progression of oral squamous carcinoma attenuates tissue integrity, facilitates cellular separation, and leads to the acquisition of a more migratory phenotype.     

A mouse model for oral squamous cell carcinoma

Despite recent advances, the prognosis of oral squamous cell carcinoma is still poor. Therapeutic options such as radiotherapy, chemotherapy, surgery and the novel treatment option gene therapy are being investigated in animal models. Diverse models have been studied to induce oral squamous cell carcinomas. The carcinogenic 4-nitroquinoline-1-oxide (4NQO) model has proven to be successful although until now it is unknown at what time point the established tumor is a representative squamous cell carcinoma and has a suitable volume for scientific treatment. For this end we applied 4NQO 3 times a week during 16 weeks and measured the volume of tumor tissue each week until the end of the experiment at 40 weeks. Concurrent histopathology at different time points up to the end of the experiment revealed that all mice bearing oral tumors were diagnosed with squamous cell carcinoma. Immunohistochemistry with markers cyclin D1 and E-cadherin revealed that the generated mouse oral tumors showed strong similarities with the described immunopathology in human oral tumors. The 4NQO model is a suitable alternative for preclinical gene therapy experiments with primary oral tumors. Future survey of therapeutic options in the carcinogenic 4NQO model should be conducted around 40 weeks after the start of the treatment.     

MicroRNA-124 suppresses oral squamous cell carcinoma motility by targeting ITGB1

Alterations in the levels of molecules which interact with the extracellular matrix, such as integrins, are associated with invasion of oral squamous cell carcinomas (OSCC). The molecular mechanisms underlying dysregulation of integrin expression in OSCC, however, remain unclear. Here, we show that microRNA-124, a small non-coding RNA down-regulated in OSCC, is able to downregulate expression of integrin beta-1 (ITGB1) by interacting with its 3′ untranslated region. Over-expression of miR-124 attenuates endogenous ITGB1 expression and reduces the adherence and motility of OSCC cells, suggesting disruption of miR-124-mediated repression of ITGB1 may be a key factor in OSCC progression.     

MTA1蛋白在食管鳞癌中的表达和临床意义

目的:探讨肿瘤转移相关基因1(MTA1)蛋白表达与食管鳞癌临床病理参数之间的关系.方法:应用免疫组化SP法和Western blotting方法检测50例食管鳞癌组织中MTA1蛋白的表达.结果:50例食管鳞癌组织中42例MTA1蛋白阳性表达,阳性率为84%.而癌旁组织中10例MTA1蛋白阳性表达,阳性率为20%,差异有显著性(P＜0.05);MTA1高表达与组织分化程度和淋巴结转移有关(P＜0.05),与年龄、性别、肿瘤大小无关(P＞0.05).结论:MTA1在食管鳞癌中高表达,与食管鳞癌的疾病进展密切相关,并有望成为基因治疗的新靶点.