Induction of alpha2-antiplasmin inhibits E-cadherin processing mediated by the plasminogen activator/plasmin system, leading to suppression of progression of oral squamous cell carcinoma via upregulation of cell-cell adhesion

The plasminogen activator/plasmin system is one of the main protease systems involved in tumor cell invasion and metastasis. Our previous study has shown that plasmin degrades E-cadherin and promotes cell dissemination by downregulation of E-cadherin-mediated cell-cell adhesion in oral squamous cell carcinoma (SCC) cells. To examine the effect of downregulation of the plasminogen activator/plasmin system by alpha2-antiplasmin (alpha2-AP) on cell-cell adhesion mediated by E-cadherin in oral SCC cells, the oral SCC cell line SCCKN was stably transfected with alpha2-AP cDNA. Induction of alpha2-AP expression led to the inhibition of the proteolysis of E-cadherin by plasminogen activator/plasmin in SCC cells, resulting in the enhancement of the cell aggregation and the suppression of the cell motility. Moreover, alpha2-AP also reduced the ability of SCC cells to invade type I collagen gel, and suppressed tumorigenicity in vivo. These results suggested that downregulation of the plasminogen activator/ plasmin system by alpha2-AP might be a potent therapeutic approach to prevent the progression of oral SCC.     

Regulation of squamous cell carcinoma antigen production by E-cadherin mediated cell-cell adhesion in squamous cell carcinoma cell line

Squamous cell carcinoma antigen (SCCA) is a useful tumor marker for diagnosis and management of squamous cell carcinoma. It is well known that cell-cell adhesion is important for progression of cancer. However, it is not clarified whether cell-cell adhesion affects SCCA production in squamous cell carcinoma. The present study was, therefore, undertaken to investigate whether E-cadherin-mediated cell-cell adhesion affects SCCA production in squamous cell carcinoma of the uterine cervix. SKG-IIIa cells or CaSki cells, cervical squamous cell carcinoma cell lines, were treated with anti-E-cadherin antibodies (1 microg/ml) up to 72 h. The cells were dissociated, and SCCA content in the cytosol and SCCA mRNA levels were significantly decreased compared to the control group treated with mouse IgG. Secondly, the signaling pathway for SCCA production mediated by E-cadherin was examined. Phosphatidylinositol (PI) 3-kinase is a well-known mediator of E-cadherin-mediated biological events. The treatment with a PI 3-kinase inhibitor suppressed SCCA production in SKG-IIIa cells. It is concluded that E-cadherin mediated cell-cell adhesion maintains SCCA production through PI 3-kinase in squamous cell carcinoma.     

Plasminogen activator mediated degradation of subendothelial extracellular matrix by human squamous carcinoma cell lines

Extracellular matrix (ECM) produced by bovine corneal endothelial cells was used to investigate the role of the plasminogen activator/plasmin system in the degradation of ECM by human squamous cell carcinoma (SqCCs) and human foreskin epidermal cells (HFEC). SqCCs caused an 8- to 34-fold greater solubilization of 3H-glucosamine-labeled ECM than HFEC. This action in SqCCs was dependent upon the presence of acid-treated serum, indicating that tumor-associated proteinases were sensitive to the inhibitory action of acid-labile proteinase inhibitors present in the serum. SqCC mediated digestion of radiolabeled ECM was decreased by 14- to 55-fold in plasminogen depleted serum, and the addition of 100 micrograms/mL of purified human plasminogen resulted in up to a 30-fold increase in the degradation of the ECM. Inhibitors of this proteinase system and murine monoclonal antibodies (MAb) specific for human urokinase plasminogen activator (uPA) decreased the SqCC mediated digestion of radiolabeled ECM in a concentration dependent manner. SqCCs exhibited 10- to 30-fold higher extracellular uPA levels than HFEC, as assayed by substrate hydrolysis, zymography, micro-ELISA, western analysis, and northern analysis. These findings reflect the differential ability of these cell types to degrade the ECM. In addition, immuno-cross-reactive plasminogen activator inhibitor type I (PAI type 1) and type II (PAI type 2) were identified in cell-free conditioned medium produced by both tumor cells and normal epidermal cells, using a micro-ELISA assay. Indirect immunofluorescence flow cytometry, employing MAbs directed against uPA, detected the presence and localization of uPA on the SqCC cell surface. These findings were specific for uPA, since cell surface associated tissue plasminogen activator was not detected in these cell types under analogous conditions. In addition, partially purified SqCC plasma membrane preparations exhibited 2- to 10-fold higher uPA-like activity than HFEC, as determined by zymography. The findings support the concept that the plasminogen activator system is important in the breakdown of ECM by SqCCs and suggest that regulatory mechanisms involved in this proteolytic system may be important targets for chemotherapeutic intervention to limit tumor cell invasion and metastasis.     

The inhibition of RANKL/RANK signaling by osteoprotegerin suppresses bone invasion by oral squamous cell carcinoma cells

Oral squamous cell carcinomas (OSCCs) are malignant tumors that frequently invade the maxilla and mandibular bone. However, the molecular mechanisms underlying bone invasion by OSCC are unclear. Recent studies showed that receptor activator of nuclear factor κB (RANK) was expressed not only in osteoclast precursors but also in tumor cells. Therefore, we examined whether RANK ligand (RANKL)/RANK signaling regulates bone invasion by OSCC cells in vivo and in vitro. We first injected human OSCC B88 cells into the masseter region of nude mice. Mice were treated for 3 weeks with osteoprotegerin (OPG), the decoy receptor for RANKL. Treatment with OPG decreased bone invasion by B88 cells, reduced the number of osteoclasts and increased B88 cell apoptosis. However, OPG did not affect apoptosis and proliferation in B88 cells in vitro, suggesting that the effects of OPG on apoptosis in B88 cells are restricted in a bone environment. RANK was expressed in the B88 cells and in OSCC cells from patients. RANKL induced NF-κB activation and extracellular signal-regulated kinase phosphorylation in B88 cells and enhanced B88 cell migration in a modified chemotaxis chamber equipped with a gelatin-coated filter. OPG inhibited RANKL-induced NF-κB activation, extracellular signal-regulated kinase phosphorylation and cell migration. Our data clearly indicate that RANKL/RANK inhibition suppresses bone invasion by inhibiting osteoclastogenesis and cancer cell migration and by inducing apoptosis of cancer cells via indirect anticancer action in vivo.     

Expression of E-Cadherin in Oral Squamous Cell Carcinoma is Associated with Clinical Prognosis

E-cadherin is a member of the cadherin superfamily, which are calcium-dependent intercellular adhesion molecules believed to play a role in cell recognition and segregation, morphogenetic regula- tion, and tumor suppression,[1] Reduced expression of E-cad…     

黏着斑激酶与口腔鳞状细胞癌关系的研究进展

黏着斑激酶（focal adhesion kinase,FAK）是一种位于细胞内的非受体型酪氨酸激酶,介导多条信号通路,在肿瘤生长、发展及转移过程中起至关重要的作用。口腔肿瘤中 95%是来源于口腔黏膜的鳞状细胞癌,深入了解 FAK 与口腔鳞状细胞癌的关系,有助于更好地预防和治疗口腔鳞状细胞癌,本文就 FAK 与口腔鳞状细胞癌关系的研究进展作一综述。     

MicroRNA-9 promotes tumor metastasis via repressing E-cadherin in esophageal squamous cell carcinoma

MicroRNAs (miRNAs) play a critical role in development and progression of cancers. Deregulation of MicroRNA-9 (miR-9) has been documented in many types of cancers but their role in the development of esophageal squamous cell carcinoma (ESCC) has not been studied. This study aimed to investigate the effect of miR-9 in esophageal cancer metastasis. The up-regulation of miR-9 was frequently detected in primary ESCC tumor tissue, which was significantly associated with clinical progression (P = 0.022), lymph node metastasis (P = 0.007) and poor overall survival (P < 0.001). Functional study demonstrated that miR-9 promoted cell migration and tumor metastasis, which were effectively inhibited when expression of miR-9 was silenced. Moreover, we demonstrated that miR-9 interacted with the 3′-untranslated region of E-cadherin and down-regulated its expression, which induced β-catenin nuclear translocation and subsequently up-regulated c-myc and CD44 expression. In addition, miR-9 induced epithelial-mesenchymal transition (EMT) in ESCC, a key event in tumor metastasis. Taken together, our study demonstrates that miR-9 plays an important role in ESCC metastasis by activating β-catenin pathway and inducing EMT via targeting E-cadherin. Our study also suggests miR-9 can be served as a new independent prognostic marker and/or as a novel potential therapeutic target for ESCC.     

Reduced E-cadherin expression is an indicator of unfavourable prognosis in oral squamous cell carcinoma

The aim was to evaluate E-cadherin expression in oral squamous cell carcinoma, and its possible relationships with tumour histology and with clinical course and survival. Surgical biopsies from 47 cases of oral squamous cell carcinoma were analysed for expression of E-cadherin using immunohistochemistry. Statistical analyses were performed to identify possible associations with tumour clinic-histological features and with clinical course and survival. Weak or absent E-cadherin expression was associated with a more invasive histological pattern and with metastasis to the cervical lymph nodes. Uni- and multivariate analyses indicated that weak or undetectable E-cadherin expression is an indicator of shorter disease-free period and shorter survival time. Reduced E-cadherin expression in oral squamous cell carcinoma is associated with more aggressive tumour behaviour and worse prognosis.     

Carvacrol抑制ADAM9在口腔鳞状细胞癌中的表达

目的:探讨carvacrol对口腔鳞状细胞癌中ADAM9表达的影响。方法:蛋白印记法分析carvacrol处理的口腔鳞状细胞癌中的去整合素金属蛋白酶9（ADAM9）蛋白表达。另外,提取40 μmol/L carvacrol处理24小时的UM-SCC-23细胞系和Tca8113细胞系中总RNA进行反转录,利用实时定量PCR（real-time PCR）扩增检测ADAM9基因表达。结果:Carvacrol明显降低UM-SCC-23细胞系和Tca8113细胞系ADAM9的蛋白和基因表达。结论:研究揭示了carvacrol的重要机制,可能为口腔鳞状细胞癌治疗提供新的理论依据。     

Twist和E-cadherin蛋白在口腔鳞状细胞癌中的表达及临床意义

目的:研究转录因子Twist和上皮细胞钙黏蛋白(E-cadherin)在口腔鳞状细胞癌(OSCC)中的表达,探讨其与OSCC发生发展的关系.方法:采用免疫组化SP法分别检测Twist和E-cadherin在20例正常口腔黏膜组织和78例OSCC组织中的表达,用Spearman秩相关分析Twist和E-cadherin在OSCC组织中表达的相关性.结果:Twist在OSCC组织中的表达明显高于正常口腔黏膜组织(P<0.05);E-cadherin蛋白在OSCC组织中的表达明显低于正常口腔黏膜组织(P<0.05);E-cadherin在Ⅲ、Ⅳ期OSCC组织中的表达低于Ⅰ、Ⅱ期(P<0.05);E-cadherin在淋巴结转移患者的OSCC组织中的表达低于无转移者(P<0.05);Twist在Ⅲ、Ⅳ期OSCC组织中的表达高于Ⅰ、Ⅱ期(P<0.05);Twist在淋巴结转移患者的OSCC组织中的表达高于无转移者(P<0.05);OSCC组织中Twist的表达与E-cadherin的表达呈显著负相关(r=-0.639,P<0.05).结论:Twist与E-cadherin在OSCC组织中异常表达,且两者的表达高度相关,提示两者可能参与OSCC的发生、发展、浸润和转移,联合检测Twist和E-cadherin对OSCC的预防诊治及预后评估具有较大的临床价值.     

朗氏细胞在口腔鳞状细胞癌中的作用(英文)

During the initiation, promotion, and progression of multi-step carcinogenesis, changes in specific host immunological factors have been observed. Although immunology of oral cancer has long been focused on antigens and lymphocytes, the fact remains that the antigen presenting cells, like the Langerhans cells (LCs) of the epithelium are initiators and modulators of the immune response. LCs as sentinels of immune response, have been investigated in several oral mucosal diseases, including cancer. Inadequate presentation of tumor antigens by host dendritic cells is one potential mechanism that allows tumor progression. In this review, the role of LCs in OSCC is discussed. Elucidation of the role of APCs, in particular LCs, may help to better understand the mechanisms underlying anti-tumour immune responses and, improve the effectiveness of anti-cancer immunity in tumour-bearing hosts. This section focuses on the roles LCs in the immunity of cancer and how cancer bypasses the dendritic cell-mediated immune responses, are discussed. Subsequently, the effects of tumor microenviornment on LC’s and their therapeutic implications are elaborated.     

Overexpression of Interleukin-6 suppresses cisplatin-induced cytotoxicity in esophageal squamous cell carcinoma cells

Interleukin-6 (IL-6) expression at local tumor sites or in systemic circulation is associated with disease progression and poor prognosis of esophageal cancer. The aim of this study was to investigate the possible influence of IL-6 on biological activities of esophageal cancer cells in terms of chemosensitivity. Human esophageal cancer cell lines TE13 and KYSE170 were transfected with a plasmid vector expressing IL-6 and stable transfectants overexpressing IL-6 were thus established. The sensitivity of IL-6 transfectants to cisplatin was evaluated using a WST-8 assay and cell-cycle analysis. In addition, the inhibitory effects of IL-6-specific siRNAs were investigated. IL-6 transfectants showed significantly reduced sensitivity to cisplatin compared to control transfectants. In addition, the reduced cisplatin sensitivity of IL-6 transfectants was restored by pretreatment with IL-6-specific siRNA. These results suggest that intracellular IL-6 expression in tumor cells may acts as a resistance factor against cisplatin-based treatments for esophageal cancer.     

Chemopreventive alteration of the cell-cell adhesion in head and neck squamous cell cancer

Approximately 310,000 new cases of oral and pharynx cancer account for a major cause of neoplasm related morbidity and mortality world-wide. Unfortunately, the survival rate has not improved significantly in the last decade. The vast majority of head and neck cancer is squamous cell carcinoma. The major adhesion-proteins involved in the development and maintenance of all solid tissue are the Cadherins. Cadherins are the transmembrane components of the adherent junction with interaction with plakoglobin and beta-catenin. Downregulation of Cadherins and catenins is frequently observed in many types of human cancer. Sulindac sulfone is one of the new therapeutic apoptotic agents that show promise in the treatment of cancer. In this study, we incubated sulindac sulfone with a head and neck cancer cell line and investigated the outcome of E-Cadherin. Immunohistochemical and Western blot analyses were then performed, with different concentrations of sulindac sulfone (100, 200, 400, 600, and 800 microMol) for 48 h. At 400 microMol of sulindac sulfone a decrease of 21% was observed; at 600 microMol, 44% decrease of beta-catenin concentration was seen, and incubation with 800 microMol resulted in 73% reduction of secreted beta-catenin. Incubation with sulindac sulfone seemed to stop proliferation; however, with respect to the controls, there was no increased reduction of the total protein. Sulindac sulfone resulted in an increase of E-Cadherin content in the head and neck squamous cell cancer cell line after 48 h of incubation; however, the reactivity was restricted to the adherent junctions. At increasing concentrations of sulindac sulfone, intercellular E-Cadherin immunostaining intensifyied. ELISA also depicted significant rising levels of E-Cadherin. Sulindac sulfone contributes to the inactivation of cGMP phospho-diesterase. Thus, the accumulation of cellular cGMP and protein kinase G is induced. The following degradation of the phosphorylated beta-catenin and the dissociation from the Cadherin-catenin complex releases E-Cadherin. This may also contribute to growth inhibition and co-ordinate with apoptosis induction. It is not really clear as to, which pathway results in the elevation of the E-Cadherin proteins. However, in epithelial cancer cells, the Cadherin-catenin complex serves as a target for the chemopreventive agent, sulindac sulfone.     

蛋白水解诱导因子在食管鳞状细胞癌中的表达

目的：研究蛋白水解诱导因子（proteolysis-inducing factor,PIF）在食管鳞状细胞癌中的表达及意义。方法：应用免疫组化方法,检测PIF在107例食管鳞状细胞癌病人癌组织以及其中35例癌旁正常组织以及8例食管良性疾病标本中的表达情况,并探讨PIF表达与食管癌临床分期、肿瘤分化程度的关系。结果：食管鳞状细胞癌组织中存在PIF表达,其表达与食管良性疾病对照组中的表达差异有统计学意义（P〈0．05）,肿瘤组织中表达PIF的个体其癌旁正常组织中亦有PIF表达,PIF表达在肿瘤分化、是否侵及浆膜层、有无淋巴结转移和肿瘤分期中的差异无统计学显著性（P〉0．05）。结论：食管鳞状细胞癌组织中存在PIF表达,其表达与肿瘤分化、是否侵及浆膜层、有无淋巴结转移和肿瘤分期无关。