Tumor budding correlates with poor prognosis and epithelial‐mesenchymal transition in tongue squamous cell carcinoma

J Oral Pathol Med (2011) 40 : 545–551 Background: Tumor budding is a readily detectable histopathological feature and has been recognized as an adverse prognostic factor in several human cancers. However, the prognostic value of tumor budding in tongue squamous cell carcinoma (TSCC) has not been reported. The purpose of this study was to assess the correlation of tumor budding with the clinicopathologic features, and the known molecular biomarkers (E‐cadherin and Vimentin), as well as to evaluate its prognostic significance for TSCC. Methods: Archival clinical samples of 230 patients with TSCC were examined for tumor budding. Immunohistochemistry analyses were performed to examine the expression of E‐cadherin and Vimentin. Statistical analyses were carried out to assess the correlation of tumor budding with clinicopathologic parameters and patient survival. The potential association between tumor budding and alterations of E‐cadherin and Vimentin expression was also assessed. Results: Of the 230 TSCC cases examined, tumor budding was observed in 165 cases (71.7%), with a mean tumor bud count of 7.5 (range from 1 to 48 buds). High‐intensity budding (≥5 tumor buds) was observed in 111 cases (48.3%). Statistical analysis revealed that tumor budding was associated with tumor size (P < 0.05), differentiation (P < 0.05), clinical stage (P < 0.05), lymph node metastasis (P < 0.01), and correlated with reduced overall survival. In addition, significant associations were observed among tumor budding and the deregulation of E‐cadherin (P < 0.001) and Vimentin (P < 0.001). Conclusions: Tumor budding, which associates with epithelial–mesenchymal transition, is a frequent event and appears to be an independent prognostic factor in TSCC.     

EGF/TGFβ1 co‐stimulation of oral squamous cell carcinoma cells causes an epithelial–mesenchymal transition cell phenotype expressing laminin 332

J Oral Pathol Med (2011) 40 : 46–54 Epithelial–mesenchymal transition (EMT) is suggested to be crucial for the development of an invasive and metastatic carcinoma cell phenotype. Therefore, the definition of this phenotype is of great clinical interest. We recently evidenced vimentin positive cells in oral squamous cell carcinoma (OSCC) invasive front expressing laminin γ2 chain mRNA implicating an EMT origin of these cells. To further elucidate the nature of these cells, we have investigated the relation between EMT criteria and laminin‐332 expression in a cell culture model of transforming growth factor beta‐1 (TGFβ1)/epithelial growth factor (EGF) long time co‐stimulation. We demonstrate that in contrast to TGFβ1 or EGF alone, co‐stimulation induces phenotype transition in OSCC cells which fulfils the criteria of EMT in terms of vimentin up‐regulation and E‐cadherin down‐regulation on protein level as well as cell scattering. Furthermore, cells displayed a strongly enhanced invasiveness and adhesion to type I‐IV collagens. Phenotype transition is accompanied by an enhanced expression of laminin‐332, especially of its γ2 chain. We further analyse the expression of extracellular matrix related genes by RT‐PCR profiling. With respect to strongly enhanced proteins, data confirm the EMT phenotype of co‐stimulated OSCC cells and expression of laminin‐332. Furthermore, alpha catenin, collagen type 16, the integrin α7 and β1 chains, and MMP11 are suggested as candidates with potential role in EMT in OSCC. In summary we are able to show that EMT in OSCC is mediated by multiple growth factors and is accompanied by laminin γ2 chain up‐regulation evidencing the existence of an intermediate Vim⁺/Ln332⁺ EMT phenotype as seen in situ.     

Human immunodeficiency virus interaction with oral and genital mucosal epithelia may lead to epithelial–mesenchymal transition and sequestration of virions in the endosomal compartments

Oral and genital mucosal epithelia are multistratified epithelial barriers with well‐developed tight and adherens junctions. These barriers serve as the first line of defense against many pathogens, including human immunodeficiency virus (HIV). HIV interaction with the surface of mucosal epithelial cells, however, may activate transforming growth factor‐beta (TGF‐β) and mitogen‐activated protein kinase signaling pathways. When activated, these pathways may lead to the disruption of epithelial junctions and epithelial–mesenchymal transition (EMT). HIV‐induced impairment of the mucosal barrier may facilitate the spread of pathogenic viral, bacterial, fungal, and other infectious agents. HIV‐induced EMT promotes highly motile/migratory cells. In oral and genital mucosa, if EMT occurs within a human papillomavirus (HPV)‐infected premalignant or malignant cell environment, the HPV‐associated neoplastic process could be accelerated by promoting viral invasion of malignant cells. HIV also internalizes into oral and genital mucosal epithelial cells. The majority (90%) of internalized virions do not cross the epithelium, but are retained in endosomal compartments for several days. These sequestered virions are infectious. Upon interaction with activated peripheral blood mononuclear cells and CD4+ T lymphocytes, epithelial cells containing the virus can be transferred. The induction of HIV‐1 release and the cell‐to‐cell spread of virus from epithelial cells to lymphocytes is mediated by interaction of lymphocyte receptor function‐associated antigen‐1 with the epithelial cell receptor intercellular adhesion molecule‐1. Thus, mucosal epithelial cells may serve as a transient reservoir for HIV, which could play a critical role in viral transmission.     

下调性别决定区Y框蛋白9对口腔鳞癌细胞上皮间质转化及克隆能力的影响

目的 探讨下调性别决定区Y框蛋白9（SOX9）对口腔鳞癌（OSCC）细胞上皮间质转化（EMT）及克隆能力的影响。方法 OSCC BcaCD885细胞中转染siRNA control、SOX9 siRNA,同时以不做任何转染的细胞作为control组。实时定量聚合酶链式反应（qRT-PCR）和Western blot筛选干扰效果较好的SOX9 siRNA1做后续研究。细胞克隆实验测定细胞克隆形成能力,免疫荧光检测上皮钙黏附素（E-cadherin）、波形蛋白（Vimentin）表达,Western blot检测E-cadherin、基质金属蛋白酶-2（MMP-2）、Vimentin、基质金属蛋白酶-9（MMP-9）表达,Transwell小室检测细胞侵袭和迁移。结果 SOX9 siRNA组细胞中SOX9 mRNA和蛋白水平均明显低于control组（P<0.05）。SOX9 siRNA1细胞克隆形成数目、细胞侵袭和迁移数目明显降低,并且细胞中MMP-2、MMP-9蛋白水平也明显降低,与control组相比,差异具有统计学意义（P<0.05）。SOX9 siRNA1组细胞中Vimentin表达水平降低,而E-cadherin表达水平升高,细胞EMT受到抑制,与control组相比,差异具有统计学意义（P<0.05）。结论 下调SOX9可抑制OSCC细胞EMT和克隆形成,以及细胞侵袭和迁移。