慢性牙周炎与口腔鳞状细胞癌关系的研究进展

口腔鳞状细胞癌(oral squamous cell carcinoma,OSCC)的发病率和死亡率呈年轻化趋势上升,已成为世界范围内的主要公共卫生问题.近年来,慢性牙周炎(chronic periodontitis,CP)与口腔鳞癌之间的关系越来越受到重视,一些研究发现,以慢性炎症和微生物失调为特征的牙周病是口腔肿瘤...     

Involvement of TSC genes and differential expression of other members of the mTOR signaling pathway in oral squamous cell carcinoma

Background  

Despite extensive research, the five-year survival rate of oral squamous cell carcinoma (OSCC) patients has not improved. Effective treatment of OSCC requires the identification of molecular targets and signaling pathways to design appropriate therapeutic strategies. Several genes from the mTOR signaling pathway are known to be dysregulated in a wide spectrum of cancers. However, not much is known about the involvement of this pathway in tumorigenesis of OSCC. We therefore investigated the role of the tumor suppressor genes, TSC1 and TSC2, and other members of this pathway in tumorigenesis of OSCC.     

Mcl-1 is an important therapeutic target for oral squamous cell carcinomas

Oral and oropharyngeal cancers are the sixth most common cancers worldwide. Despite intensive investigation, oral squamous cell carcinomas (OSCC) represent a clinical challenge resulting in significant morbidity and mortality. Resistance to cell death is common in OSCC and is often mediated by the Bcl-2 family proteins. Among all anti-apoptotic Bcl-2 family members, Mcl-1 functions as a major survival factor, particularly in solid cancers. Despite the confirmed importance of Mcl-1 in several neoplasms, the role of Mcl-1 in OSCC survival has yet to be explored. In this study, we found that knocking down Mcl-1 sensitized OSCC cells to ABT-737, which binds to Bcl-2/Bcl-x_L but not Mcl-1. We report for the first time that a BH3 mimetic, Sabutoclax, which functions as an inhibitor of all anti-apoptotic Bcl-2 proteins, induced cancer-specific cell death in an Mcl-1-dependent manner through both apoptosis and toxic mitophagy. In vivo studies demonstrated that Sabutoclax alone decreased tumor growth in a carcinogen-induced tongue OSCC mouse model. In a combination regimen, Sabutoclax and COX-2 inhibitor, Celecoxib, synergistically inhibited the growth of OSCC in vitro and also significantly reduced OSCC tumor growth in vivo. Overall, these results identify Mcl-1 as a therapeutic prospective target in OSCC.     

Investigation of bone invasion and underlying mechanisms of oral cancer using a cell line-derived xenograft model

The cancer stroma regulates bone invasion in oral squamous cell carcinoma (OSCC). However, data on normal stroma are limited. In the present study, the effects of gingival and periodontal ligament tissue-derived stromal cells (G-SCs and P-SCs, respectively) and human dermal fibroblasts (HDFs) on bone resorption and osteoclast activation were assessed using hematoxylin and eosin and tartrate-resistant acid phosphatase staining in a cell line-derived xenograft model. The results demonstrated that G-SCs promoted bone invasion and osteoclast activation and inhibited osteoclast proliferation following crosstalk with the human OSCC HSC-3 cell line, whereas P-SCs inhibited bone resorption and promoted osteoclast proliferation in vitro but had a minimal effect on osteoclast activation both in vitro and in vivo following crosstalk with HSC-3 cells. Furthermore, the effects of G-SCs, P-SCs and HDFs on protein expression levels of matrix metalloproteinase (MMP)-9, membrane type 1 MMP (MT1-MMP), Snail, parathyroid hormone-related peptide (PTHrP) and receptor activator of NF-κB ligand (RANKL) in HSC-3 cells in OSCC bone invasion regions were assessed using immunohistochemistry. The results demonstrated that G-SCs had a more prominent effect on the expression of MMP-9, MT1-MMP, Snail, PTHrP, and RANKL, whereas P-SCs only promoted RANKL and PTHrP expression and exerted a minimal effect on MMP-9, MT1-MMP and Snail expression. The potential genes underlying the differential effects of G-SCs and P-SCs on bone invasion in OSCC were evaluated using a microarray, which indicated that cyclin-dependent kinase 1, insulin, aurora kinase A, cyclin B1 and DNA topoisomerase II alpha underlaid these differential effects. Therefore, these results demonstrated that G-SCs promoted bone invasion in OSCC by activating osteoclasts on the bone surface, whereas P-SCs exerted an inhibitory effect. These findings could indicate a potential regulatory mechanism for bone invasion in OSCC.     

Sirtuin-3 (SIRT3), a novel potential therapeutic target for oral cancer

BACKGROUND:

Several sirtuin family members (SIRT1‐7), which are evolutionarily conserved NAD‐dependent deacetylases, play an important role in carcinogenesis. However, their role in oral cancer has not yet been investigated. Therefore, the objective of this study was to investigate whether sirtuins play a role in oral cancer carcinogenesis.

METHODS:

The expression levels of all sirtuins in several oral squamous cell carcinoma (OSCC) cell lines were compared with normal human oral keratinocytes and observed that SIRT3 was highly expressed. Therefore, tissue microarrays were used to evaluate the clinical relevance of this overexpression. SIRT3 down‐regulation in OSCC cell proliferation and survival was investigated and analyzed by using cell‐proliferation and cell‐viability assays. Ionizing radiation and cisplatin were used to investigate whether SIRT3 down‐regulation could increase the sensitivity of OSCC to both treatments. To further assess the in vivo role of SIRT3 in OSCC carcinogenesis, a floor‐of‐mouth oral cancer murine model was used to study the effect of SIRT3 down‐regulation on OSCC tumor growth in immunodeficient mice.

RESULTS:

The current results demonstrated for the first time that SIRT3 is overexpressed in OSCC in vitro and in vivo compared with other sirtuins. Down‐regulation of SIRT3 inhibited OSCC cell growth and proliferation and increased OSCC cell sensitivity to radiation and cisplatin treatments in vitro. SIRT3 down‐regulation also reduced tumor burden in vivo.

CONCLUSIONS:

The current investigation revealed a novel role for SIRT3 in oral cancer carcinogenesis as a promoter of cell proliferation and survival, thus implicating SIRT3 as a new potential therapeutic target to treat oral cancer. Cancer 2011. © 2010 American Cancer Society.     

Elevated USP9X drives early-to-late-stage oral tumorigenesis via stabilisation of anti-apoptotic MCL-1 protein and impacts outcome in oral cancers

Background Overexpression of anti-apoptotic MCL-1 protein in oral squamous cell carcinoma (OSCC) is linked to disease progression, therapy resistance and poor outcome. Despite its characteristic short half-life owing to ubiquitin–proteasome-dependent degradation, oral tumours frequently show elevated MCL-1 protein expression. Hence, we investigated the role of deubiquitinase USP9X in stabilising MCL-1 protein and its contribution to oral tumorigenesis.Methods Expression of MCL-1 and USP9X was assessed by immunoblotting and immunohistochemistry in oral cancer cell lines and tissues. The association between MCL-1 and USP9X was confirmed by coimmunoprecipitation and immunofluorescence. Cell death assessment was performed by MTT, flow cytometry and clonogenic assays.Results Both USP9X and MCL-1 are significantly elevated in oral premalignant lesions and oral tumours versus normal mucosa. USP9X interacts with and deubiquitinates MCL-1, thereby stabilising it. Pharmacological inhibition of USP9X potently induced cell death in OSCC cells in vitro and in vivo. The elevated expression of USP9X and MCL-1 correlated with poor prognosis in OSCC patients.Conclusion We demonstrate the oncogenic role of USP9X in driving early-to-late stages of oral tumorigenesis via stabilisation of MCL-1, suggesting its potential as a prognostic biomarker and therapeutic target in oral cancers.Subject terms: Oral cancer detection, Oral cancer detection     

Antitumor effects of BI-D1870 on human oral squamous cell carcinoma

Purpose

Among the signaling pathways implicated in the tumorigenesis of oral squamous cell carcinoma (OSCC) is the extracellular signal-regulated kinase mitogen-activated protein kinase pathway, a downstream target of which is a family of serine/threonine kinases known as the 90 kDa ribosomal S6 kinases (RSKs). This study aims to investigate the role of BI-D1870, a specific inhibitor of p90 RSKs, in a panel of OSCC cell lines.

Methods

The antitumor effects and mechanisms of BI-D1870 were assessed by MTT assays, flow cytometry, Western blotting, transfection, and confocal microscopy.

Results

BI-D1870 exhibited a dose-responsive antiproliferative effect on OSCC cells with relative sparing of normal human oral keratinocytes. The compound inhibited the downstream RSK target YB-1 and caused apoptosis as evidenced by PARP cleavage, activation of the caspase cascade, and the presence of pyknotic nuclei in the 4,6-diamidino-2-phenylindole assay. In addition, BI-D1870 also induced G2/M arrest by modulating the expression of p21 and other cell cycle regulators. Other newly discovered anticancer attributes of BI-D1870 included the generation of reactive oxygen species and increases in endoplasmic reticulum stress and autophagy.

Conclusions

Together, these results suggest the translational value of BI-D1870 in oral squamous cell carcinoma therapy.     

Serum levels of osteopontin as a prognostic factor in patients with oral squamous cell carcinoma

Osteopontin (OPN) is a multifunctional glycophosphoprotein that was detected in many carcinomas, and it may have a prognostic role. The aim of this study was to determine osteopontin serum levels in patients with oral squamous cell carcinoma (OSCC) and investigated its correlation with clinicopathological features of tumor. Using an ELISA kit, we assessed and compared the circulating levels of OPN in blood serum of 45 oral squamous cell carcinoma patients with 45 healthy control samples. The serum osteopontin level in patients with OSCC was significantly higher (145.8?±?14.6 ng/ml, n?=?45) compared with the healthy controls (53.9?±?9.6 ng/ml, n?=?45, p?<?0.001). Mean serum osteopontin level was significantly higher in patients with nodal metastasis (p?=?0.03) and higher stage (p?=?0.02). Findings of the present study suggest that OPN may have a potential role in pathogenesis of OSCC and it may be used as a tool for monitoring tumor progression.     

口腔鳞癌组织中Survivin蛋白的表达及与血管生成的关系

背景与目的:Survivin蛋白主要通过抑制Caspase-3、Caspase-7阻断细胞凋亡过程,在多种常见恶性肿瘤组织中有表达。本研究拟探讨Survivin在口腔鳞癌发生发展中的作用及与血管生成的关系。方法:采用免疫组织化学SP法,检测8例正常口腔粘膜、14例上皮异常增生性白斑、47例鳞癌组织中Survivin的表达及鳞癌中CD34的表达,并计数微血管密度(MVD),分析口腔鳞癌中Survivin与MVD及临床病理特征的关系。结果:Survivin在正常口腔粘膜、异常增生性白斑及鳞癌组织中的阳性率分别为0%(0/8)、14.29%(2/14)和55.32%(26/47);经免疫组化半定量分析,鳞癌组Survivin表达强于正常口腔粘膜组及异常增生性白斑组(P<0.05),而后两组间无显著差别(P>0.05)。Survivin在中-低分化鳞癌组中的表达强于高分化鳞癌组(P<0.05);在有淋巴结转移组中的表达(71.43%)高于无淋巴结转移组(38.89%)(P<0.05)。口腔鳞癌中,随Survivin表达增强(-, ,2 ,3 ),MVD逐渐增高(分别为25.87±12.10,28.70±7.69,35.42±10.09,41.13±9.62)(P<0.05)。结论:Survivin蛋白在口腔鳞癌组织中表达上调;Survivin与口腔鳞癌的分化程度、淋巴结转移有关,并与MVD关系密切,提示Survivin与口腔鳞癌的发生发展过程有关。     

GDF15 is a potential predictive biomarker for TPF induction chemotherapy and promotes tumorigenesis and progression in oral squamous cell carcinoma

BackgroundRandomized trials have not shown major survival benefits when induction chemotherapy plus standard therapy is compared with standard therapy alone in patients with oral squamous cell carcinoma (OSCC). Induction chemotherapy is likely to be effective for biologically distinct subgroups and biomarker development may lead to identification of patients whose tumors are likely to respond to a particular treatment.Patients and methodsWe evaluated immunohistochemical staining for GDF15 in pretreatment biopsy specimens of 230 of 256 OSCC patients who were treated in a prospective, randomized, phase III trial on induction chemotherapy including docetaxel, cisplatin and 5-fluorouracil (TPF). Relationship between GDF15 intervention and cell proliferation, migration, invasion, colony formation and tumorigenicity was analyzed using in vitro and in vivo OSCC models.ResultsLow GDF15 expression predicted a better survival in OSCC patients, especially overall survival [P = 0.049, hazard ratio (HR) = 0.597] and distant metastasis-free survival (DMFS; P = 0.031, HR = 0.562). cN+ patients with low GDF15 expression benefitted from induction TPF in overall survival (P = 0.039, HR = 0.247) and DMFS (P = 0.039, HR = 0.247), cN- patients with high GDF15 expression benefitted from induction TPF in overall survival (P = 0.019, HR = 0.231), disease-free survival (P = 0.011, HR = 0.281), locoregional recurrence-free survival (P = 0.035, HR = 0.347) and DMFS (P = 0.009, HR = 0.197). Decreased GDF15 expression in OSCC lines significantly inhibited cell proliferation, migration, invasion, colony formation and tumorigenesis through increased phosphorylation of AKT and ERK1/2 (P < 0.05). Likewise, overexpression of GDF15 significantly promoted cell proliferation, migration, invasion and colony formation through decreased phosphorylation of AKT and ERK1/2 (P < 0.05).ConclusionsGDF15 expression can be used as a prognostic biomarker for OSCC, and as a predictive biomarker for benefitting from TPF induction chemotherapy. GDF15 promotes tumorigenesis and progression through phosphorylation of AKT and ERK1/2 in OSCC. The clinical trial in this study was registered with www.ClinicalTrials.gov (NCT01542931).     

Development of tissue-engineered models of oral dysplasia and early invasive oral squamous cell carcinoma

Background:

Current organotypic models of dysplasia and oral squamous cell carcinoma (OSCC) lack the complexity that mimics in vivo tissue. Here we describe a three-dimensional in vitro model of the oral epithelium that replicates tumour progression from dysplasia to an invasive phenotype.

Methods:

The OSCC cell lines were seeded as a cell suspension (D20, Cal27) or as multicellular tumour spheroids (FaDu) with oral fibroblasts on to a de-epidermised acellular dermis to generate tissue-engineered models and compared with patient biopsies.

Results:

The D20 and Cal27 cells generated a model of epithelial dysplasia. Overtime Cal27 cells traversed the basement membrane and invaded the connective tissue to reproduce features of early invasive OSCC. When seeded onto a model of the normal oral mucosa, FaDu spheroids produced a histological picture mimicking carcinoma in situ with severe cellular atypia juxtaposed to normal epithelium.

Conclusion:

It is possible to culture in vitro models with the morphological appearance and histological characteristics of dysplasia and tumour cell invasion seen in vivo using native dermis. Such models could facilitate study of the molecular processes involved in malignant transformation, invasion and tumour growth as well as in vitro testing of new treatments, diagnostic tests and drug delivery systems for OSCC.     

Tumor cell apoptosis mediated by cytoplasmic ING1 is associated with improved survival in oral squamous cell carcinoma patients

The ING1 epigenetic regulator and tumor suppressor plays a central role in apoptosis. The Ing1 gene is functionally inactivated in many cancer types but is rarely mutated. Although most studies have implicated the major ING1 isoform, p33ING1b, in nuclear apoptotic signalling, we recently discovered a novel and potent apoptosis-inducing effect of p33ING1b translocation to the mitochondria in response to DNA damage. In the present study, we examined the impact of cytoplasmic/mitochondrial localization of p33ING1b in oral squamous cell carcinoma (OSCC) patient samples and explored the therapeutic potential of adenovirally-overexpressed p33ING1b in OSCC cell lines in combination with ionizing radiation (IR) treatment. In contrast with previous reports, we found that p33ING1b protein and mRNA levels are higher in OSCC compared to normal epithelial cells. In OSCC patient samples, higher levels of intra-tumoral cytoplasmic p33ING1b correlated with increased apoptotic markers and significantly better patient survival. This association was strongest in patients who received post-operative radiotherapy. IR treatment induced p33ING1b translocation to the mitochondria and adenoviral-p33ING1b synergized with IR to kill OSCC cells. Our results identify a novel functional relationship between cytoplasmic p33ING1b and patient survival and highlight the potential for the use of p33ING1b as a therapeutic agent in combination with adjuvant radiotherapy in OSCC.     

应用自制组织芯片研究抑癌基因PTEN 在口腔鳞癌中的表达

 目的 从蛋白水平探讨口腔鳞癌组织中肿瘤抑制基因PTEN的表达及临床病理意义。方法 应用SP免疫组化染色法和组织芯片技术，检测10例正常口腔粘膜、10例口腔上皮单纯增生、15例口腔粘膜白斑及72例OSCC（其中高分化30例、中分化26例、低分化16例）组织中PTEN蛋白的表达，同时分析PTEN的表达与患者临床病理资料的关系。结果 PTEN基因在口腔鳞癌、口腔粘膜白斑、口腔上皮单纯增生和正常口腔粘膜组织中的阳性率分别为72．2％（52／72）、93．3％（14／15）、100％（10／10）和100％（10／10），口腔鳞癌组与其他各组间有显著性差异（P〈0．05）；PTEN的阳性表达率在不同性别、年龄和TNM分期等临床病理参数间无显著性差异（P〉0．05），但与淋巴结转移、组织分化程度等临床病理参数间有显著性差异（P〈0．05）。结论 PTEN基因表达的下调在OSCC的发生、发展中起着重要作用，其表达的异常可作为判断预后的参考指标之一。     

Long non‐coding RNA UCA1 contributes to the progression of oral squamous cell carcinoma by regulating the WNT/β‐catenin signaling pathway

With the development of functional genomics studies, a mass of long non‐coding RNAs (LncRNA) were discovered from the human genome. Long non‐coding RNAs serve as pivotal regulators of genes that are able to generate LncRNA–binding protein complexes to modulate a great number of genes. Recently, the LncRNA urothelial carcinoma‐associated 1 (UCA1) has been revealed to be dysregulated, which plays a critical role in the development of a few cancers. However, the role of the biology and clinical significance of UCA1 in the tumorigenesis of oral squamous cell carcinoma (OSCC) remain unknown. We found that UCA1 expression levels were upregulated aberrantly in tongue squamous cell carcinoma tissues and associated with lymph node metastasis and TNM stage. We explored the expression, function, and molecular mechanism of LncRNA UCA1 in OSCC. In the present work, we revealed that UCA1 silencing suppressed proliferation and metastasis and induced apoptosis of OSCC cell lines in vitro and in vivo, which might be related to the activation level of the WNT/β‐catenin signaling pathway. Our research results emphasize the pivotal role of UCA1 in the oncogenesis of OSCC and reveal a novel LncRNA UCA1–β‐catenin–WNT signaling pathway regulatory network that could contribute to our understanding in the pathogenesis of OSCC and assist in the discovery of a viable LncRNA‐directed diagnostic and therapeutic strategy for this fatal disease.     

The CS1 segment of fibronectin is involved in human OSCC pathogenesis by mediating OSCC cell spreading,migration, and invasion

Background  

The alternatively spliced V region or type III connecting segment III (IIICS) of fibronectin is important in early development, wound healing, and tumorigenesis, however, its role in oral cancer has not been fully investigated. Thus, we investigated the role of CS-1, a key site within the CSIII region of fibronectin, in human oral squamous cell carcinoma (OSCC).     

Quantitative difference of oral pathogen between individuals with gastric cancer and individuals without cancer

The loss of teeth and lack of oral hygiene have been associated with the risk of developing gastric cancer (GC) in several populations evidenced in epidemiological studies. In this study, we quantitatively compared the proportion of oral pathogens in individuals with gastric cancer and individuals without cancer in a referral hospital in the city of Belém, Brazil. This study evaluated 192 patients with GC and 192 patients without cancer. Periodontal clinical examination was performed, and all individuals were submitted to the collection of salivary and dental biofilms. When comparing the median periodontal indexes in the gastric and cancer-free groups, it was statistically significant (p < 0.001) in the gastric cancer group compared to the probing depth of the periodontal pocket. Levels of bacterial DNA were observed in saliva and dental plaque, with a statistically significant difference (p < 0.001) between individuals with cancer and without neoplasia in all the bacteria surveyed. Significant relationships (p < 0.001) between biological agents and GC have been found in bacterial species that cause high rates of periodontal pathology and caries. The results suggest a different quantitative association in the presence of oral pathogens between individuals without cancer and patients with GC. As noted, it cannot be said that the bacteria present in the oral cavity increase the risk of gastric cancer or are aggravating factors of the disease. However, it is worth mentioning that, as it is part of the digestive system, the lack of care for the oral cavity can negatively affect the treatment of patients with gastric cancer.     

Predominant Rab-GTPase amplicons contributing to oral squamous cell carcinoma progression to metastasis

Metastatic oral squamous cell carcinoma (OSCC) is frequently associated with recurrent gene abnormalities at specific chromosomal loci. Here, we utilized array comparative genomic hybridization and genome-wide screening of metastatic and non-metastatic tongue tumors to investigate genes potentially contributing to OSCC progression to metastasis. We identified predominant amplifications of chromosomal regions that encompass the RAB5, RAB7 and RAB11 genes (3p24-p22, 3q21.3 and 8p11–12, respectively) in metastatic OSCC. The expression of these Rab GTPases was confirmed by immunohistochemistry in OSCC tissues from a cohort of patients with a follow-up of 10 years. A significant overexpression of Rab5, Rab7 and Rab11 was observed in advanced OSCC cases and co-overexpression of these Rabs was predictive of poor survival (log-rank test, P = 0.006). We generated a Rab interaction network and identified central Rab interactions of relevance to metastasis signaling, including focal adhesion proteins. In preclinical models, mRNA and protein expression levels of these Rab members were elevated in a panel of invasive OSCC cell lines, and their down-regulation prevented cell invasion at least in part via inhibition of focal adhesion disassembly. In summary, our results provide insights into the cooperative role of Rab gene amplifications in OSCC progression and support their potential utility as prognostic markers and therapeutic approach for advanced OSCC.