The role of cell adhesion molecules in cancer invasion and metastasis

Summary Invasion and metastasis of tumor cells is the primary cause for the fatal outcome of cancer diseases. A striking feature of metastatic cells is the considerable flexibility in their adhesive interactions with other cells or components of the extracellular matrix. This review will describe the involvement of specific cell adhesion receptors, extracellular matrix molecules, and cell dissociating cytokines in the metastatic cascade. We will particularly focus on disturbance of intercellular adhesion as a prerequisite for the release of invasive cells from carcinomas. We suggest that cell dissociation in these tumors is accomplished by loss of function or expression of the epithelial cell adhesion molecule E-cadherin, and through the activity of cell motility factors, like scatter factor.     

Carbohydrate-mediated cell adhesion in cancer metastasis and angiogenesis

Malignant transformation is associated with abnormal glycosylation, resulting in the synthesis and expression of altered carbohydrate determinants including sialyl Lewis^a and sialyl Lewis^x. The sialyl Lewis^a and sialyl Lewis^x determinants appear in the sera of patients with cancer, and are extensively utilized for serum diagnosis of cancers in Japan. Sialyl Lewis^a and sialyl Lewis^x are involved in selectin-mediated adhesion of cancer cells to vascular endothelium, and these determinants are thought to be closely associated with hematogenous metastasis of cancers. Recent progress in this area includes the following: 1. Substantial increases in solid clinical statistics that further confirm the contribution of these determinants in the progression of a wide variety of cancers; 2. Elucidation of the ligand specificity of the three family members of selectins and evaluation of the roles of these molecules in cancer cell adhesion; and 3. Advances in the study of the mechanism that leads to the enhanced expression of the sialyl Lewis^a/x determinants in malignant cells. These recent results have confirmed that these determinants are not merely markers for cancers, but are functionally implicated in the malignant behavior of cancer cells. The results also suggested that the increase of these determinants in malignant cells is an inevitable consequence of the malignant transformation of cells. Considerable new knowledge has also been accumulated regarding the therapeutic implications for suppression of hematogenous metastasis targeting this cell adhesion system.     

Inhibition of cancer cell invasion and metastasis by genistein

Genistein is a small, biologically active flavonoid that is found in high amounts in soy. This important compound possesses a wide variety of biological activities, but it is best known for its ability to inhibit cancer progression. In particular, genistein has emerged as an important inhibitor of cancer metastasis. Consumption of genistein in the diet has been linked to decreased rates of metastatic cancer in a number of population-based studies. Extensive investigations have been performed to determine the molecular mechanisms underlying genistein’s antimetastatic activity, with results indicating that this small molecule has significant inhibitory activity at nearly every step of the metastatic cascade. Reports have demonstrated that, at high concentrations, genistein can inhibit several proteins involved with primary tumor growth and apoptosis, including the cyclin class of cell cycle regulators and the Akt family of proteins. At lower concentrations that are similar to those achieved through dietary consumption, genistein can inhibit the prometastatic processes of cancer cell detachment, migration, and invasion through a variety of mechanisms, including the transforming growth factor (TGF)-β signaling pathway. Several in vitro findings have been corroborated in both in vivo animal studies and in early-phase human clinical trials, demonstrating that genistein can both inhibit human cancer metastasis and also modulate markers of metastatic potential in humans, respectively. Herein, we discuss the variety of mechanisms by which genistein regulates individual steps of the metastatic cascade and highlight the potential of this natural product as a promising therapeutic inhibitor of metastasis.     

Neural cell adhesion molecule and perineural invasion in gallbladder cancer

To clarify the role of neural cell adhesion molecule (NCAM) in perineural invasion, NCAM expression was studied by immunohistochemical staining in 26 cases with gallbladder cancer. In gallbladder cancer, the incidence of perineural invasion and that of positive NCAM expression was 42% and 31%, respectively, which are less frequent than those of bile duct cancer in our previous report. Perineural invasion was observed in 88% of the patients with positive expression of NCAM and in 22% of those with negative expression. The former is similar to that of bile duct cancer but the latter is significantly lower. Eighty percent of the cancer cells that invaded the perineural space were positive for NCAM, when the primary tumor was positive for NCAM expression. Therefore, in gallbladder cancer, positive cells in NCAM expression likely invade the perineural spaces. However, the perineural invasion of negative cells in NCAM expression is not likely to occur as compared to bile duct cancer. In conclusion, perineural invasion in gallbladder cancer is not as common as in bile duct cancer, but the role of NCAM in perineural invasion is more important in gallbladder cancer than in bile duct cancer. © 1995 Wiley-Liss, Inc.     

Fibronectin in cell adhesion and invasion

Summary Fibronectin plays a major role in the adhesion of many cell types. The extent of cell adhesion in vitro is related not only to the ability of the cells to interact with matrix-bound fibronectin, when it is present, but also to the synthesis or lack of synthesis of fibronectin by the cells, and to the lack of deposition of synthesized fibronectin into an insoluble matrix surrounding the cells. Many malignant cells, regardless of whether they synthesize subnormal or normal amounts of fibronectin, fail to deposit that fibronectin into a surrounding insoluble matrix. The lack of fibronectin around such cells appears to reflect a general absence of extracellular matrix since other matrix components, such as collagen, laminin, and heparan sulfate proteoglycan, are concomitantly missing. Cells that lack their own cell surface fibronectin due either to lack of deposition or to lack of synthesis can nevertheless adhere to insoluble fibronectin matrices elaborated by other cells. These cellular characteristics appear to be associated with cell migration in vivo during embryogenesis, and the same characteristics may enhance the invasive potential of malignant cells. The remarkable effects that fibronectin has on cellular adhesion and the association of lack of extracellular matrix components with poorly differentiated and highly metastatic tumors in vivo mandates that more be learned about the molecular and cellular details of the interactions of cells with their surrounding matrix. Important information concerning tumor invasion will parallel such an understanding and may eventually become the basis for therapeutic approaches.This work was supported by grant CA 28896 and Cancer Center Support Grant CA 30199 from the National Cancer Institute, Department of Health and Human Services.     

Thrombospondin as a mediator of cancer cell adhesion in metastasis

Summary Thrombospondin (TSP) is a 450 kDa adhesive glycoprotein. It is present in high concentrations in the platelet -granule and can readily be secreted following platelet activation where local concentrations can be increased by 3–4 orders of magnitude. TSP is also synthesized by a variety of other cells and is incorporated into their extracellular matrix. TSP is a homotrimer with a number of functional domains, at least four of which might serve as receptor recognizing regions. The amino-terminal heparin binding domain interacts with heparin, other glycosaminoglycans and glycolipids and likely recognizes specific cell surface proteoglycans. The central disulfide cross-linked region, 210 kDa non-reduced and 70 kDa reduced, contains a peptide motif CSVTCG which is apparently responsible for binding to glycoprotein IV (CD36) with high affinity. Immediately adjacent to the calcium binding region of TSP, which undergoes considerable molecular relaxation in the absence of calcium, is an RGDA sequence. TSP has been demonstrated to bind to integrins of the _v3 and _IIb3 class. The carboxy-terminal region of TSP also contains at least one binding epitope for a cell receptor. There are 2 well characterized genes for TSP and truncated forms of TSP have been detected which have inhibitory effects on angiogenesis. Finally, TSP can interact with fibrinogen and fibronectin, perhaps on cellular surfaces, which might serve as secondary receptor-like mechanisms for TSP binding and subsequent mediation of cell adhesion.     

Snail蛋白对E-钙黏蛋白表达的抑制在上皮性卵巢癌细胞侵袭及淋巴结转移中的作用

目的:探讨Snail蛋白对E-钙黏蛋白(E-cad)表达的抑制在上皮性卵巢癌细胞侵袭及淋巴结转移中的作用。方法:选择人卵巢癌细胞株C13,将Snail/siRNA、Snail/smRNA分别转入C13细胞,以PBS作为空白对照组,检测E-cad蛋白表达情况,采用Transwell上室进行细胞侵袭性及淋巴结转移实验分析。结果:C13细胞空白对照组、Snail/smRNA组、Snail/siRNA组,12 h穿膜细胞数分别为98.24±7.92、90.93±8.38和21.48±4.85,Snail/siRNA组与另两组相比有显著性差异(P＜0.05);Snail/siRNA组的转移细胞与另两组相比也有显著性差异(P＜0.05)。相对于Snail/smRNA组,Snail/siRNA组细胞E-cad的蛋白水平降低,两组差异有统计学意义(P＜0.05),而空白对照组则没有明显变化(P＞0.05）。结论:Snail蛋白对E-cad表达的抑制能抑制上皮性卵巢癌细胞的侵袭及转移,能够在分析卵巢癌转移分子机制时给予理论支持,为靶向逆转的研究提供了可供参考的靶点。     

尿激酶纤溶酶原激活物系统与肿瘤侵袭转移

恶性肿瘤合成分泌大量胞外蛋白水解酶,降解细胞外基质及基底膜,是恶性肿瘤侵袭转移的重要基础.尿激酶纤溶酶原激活物(uPA)系统作为主要的蛋白水解酶在其中发挥重要作用.本简述uPA系统的结构、功能及其在侵袭、转移中的作用.     

RKIP expression associated with gastric cancer cell invasion and metastasis

The purpose of this study was to analyze Raf kinase inhibitor protein (RKIP) expression in gastric cancer tissue, its correlation with gastric cancer clinical pathology, and its role in gastric cancer invasion and metastasis in order to provide experimental evidence for the potential biological therapy of this disease. Both immunohistochemistry and western blot analyses were used to test for RKIP expression in 55 cases of gastric cancer tissue and the adjacent gastric mucous membrane tissue. The correlations of RKIP expression with the onset, development, and clinical pathology of gastric cancer were analyzed. After transiently transfecting the human gastric cancer cell line MKN45 with a eukaryotic expression vector containing the full length RKIP cDNA, the changes in MKN45 cell invasiveness and metastatic ability were studied. Immunohistochemistry and western blot results revealed that the quantity of RKIP protein expressed in the gastric cancer tissues was significantly lower than that of the adjacent normal gastric mucous membrane tissues (p < 0.05). The quantity of RKIP protein expression was reduced (p < 0.05) as the gastric cancer cells' differentiation decreased, the TNM stage increased, and the extent of invasion expanded. However, the expression of RKIP in the gastric cancer tissues was not associated with the patients' age or gender (p > 0.05). By overexpressing RKIP in the human gastric cancer cell line MKN45 and through the use of a Transwell invasion chamber, we determined that RKIP overexpression significantly reduced both the invasiveness and metastatic ability of MKN45 cells (p < 0.05). Low or absent RKIP expression may be associated with the onset and development of gastric cancer and its ability to invade and metastasize.     

The E-cadherin cell-cell adhesion complex and lung cancer invasion, metastasis, and prognosis

BACKGROUND: Lung cancer is the most common cause of cancer deaths in the western world. Progress in treatment results has been limited, and the prognosis is poor with a 5-year survival less than 15%. Based on new developments in molecular biology, our knowledge about lung carcinogenesis and mechanisms for invasion and metastasis has expanded and may in the future lead to more specific targeted therapies and better prognosis. The E-cadherin-catenin complex is critical for intercellular adhesiveness and maintenance of normal and malignant tissue architecture. Reduced expression of this complex in malignant disease is associated with tumour invasion, metastasis, and unfavorable prognosis. METHODS: This review is based on search in the Medline database from 1991 to 2001. We have reviewed the relevance of the E-cadherin-catenin adhesion complex in malignancy in general and lung cancer in particular. Furthermore, its role as target for specific therapy is discussed. RESULTS: Available data indicate that alterations of proteins involved in the E-cadherin-catenin complex are early incidents in cancer development. Reduced or altered expression of one or more of the components in this complex is associated with extended invasive and progressive behavior of cancer cells. Consistently, the E-cadherin-catenin complex appears to be increasingly delicate with regard to cancer prognosis. beta-Catenin, one of the components of the adhesion complex, also plays a significant role in cell signal transduction, gene activation, apoptosis inhibition, and increased cellular proliferation and migration. CONCLUSION: Inactivation of the E-cadherin-catenin adhesion complex, induced by genetic and epigenetic events, plays a significant role in multistage carcinogenesis, and seems to be associated with dedifferentiation, local invasion, regional metastasis, and reduced survival in lung cancer.     

FBXO31 promotes cell proliferation,metastasis and invasion in lung cancer

FBXO31 is a member of F-box family which is involved in diverse biological functions and development of disease. Recent reports in breast cancer, hepatocellular carcinoma and ovarian cancer demonstrated inhibitory effect of FBXO31 on proliferation and tumorigenesis. However, the function of FBXO31 is not analyzed in lung cancer so far. In this study, we reported that expression of FBXO31 was higher in lung cancer tissues compared with non-cancerous lung tissues, and that higher expression of FBXO31 was significantly associated with tumor size, tumor infiltration, clinical stages and lymph node metastasis. In addition, exogenous expression of FBXO31 promoted cell growth, metastasis and invasion in A549 cells. Conversely, silencing FBXO31 by specific siRNA caused inhibitory effect on cell growth, metastasis and invasion. Moreover, tumorigenicity assays in nude mice showed FBXO31 promoted tumor growth in vivo. In conclusion, our data suggest FBXO31 promotes cell proliferation, metastasis and invasion in lung cancer.     

与结肠癌转移倾向相关的细胞粘附基因的筛查

目的： 利用cDNA基因芯片研究已发生转移与未发生转移的原发性结肠癌基因表达谱的差异,筛选与结肠癌转移相关的细胞粘附基因。方法：分别提取未发生转移及已发生转移的原发性结肠癌组织mRNA,逆转录成cDNA探针,经Cy3和Cy5标记后与含1.6万余点的cDNA基因芯片杂交,用专用软件分析杂交信号强度,找出与细胞粘附相关的差异基因,并进行功能分析。结果：已发生转移与未发生转移的原发性结肠癌基因表达谱有显著差异,与细胞粘附相关的基因中,荧光强度比值小于0.2或大于5.0的差异基因共26个。上调基因15个,包括CD44、ICAM1、NCAM、HMGB1、SELL、CHRNA5、CEACAM6、VCAM1、HMGA2、PECAM1、CEACAM1、CD18、ITGAL、TGFB1、ICAM-3。下调基因11个,包括CD99、CADM1、CD82、F11R、SELE、CD226、TSLC1、PTB、CAR、JAM-2、PTEN。结论：结肠癌转移是由多个基因参与的复杂过程,细胞粘附基因在转移过程中起着非常重要的作用。     

Hyperforin inhibits cancer invasion and metastasis

Hyperforin (Hyp), the major lipophilic constituent of St. John's wort, was assayed as a stable dicyclohexylammonium salt (Hyp-DCHA) for cytotoxicity and inhibition of matrix proteinases, tumor invasion, and metastasis. Hyp-DCHA triggered apoptosis-associated cytotoxic effect in both murine (C-26, B16-LU8, and TRAMP-C1) and human (HT-1080 and SK-N-BE) tumor cells; its effect varied, with B16-LU8, HT-1080, and C-26 the most sensitive (IC50 = 5 to 8 micromol/L). At these concentrations, a marked and progressive decline of growth was observed in HT-1080 cells, whereas untransformed endothelial cells were only marginally affected. Hyp-DCHA inhibited in a dose-dependent and noncompetitive manner various proteinases instrumental to extracellular matrix degradation; the activity of leukocyte elastase was inhibited the most (IC50 = 3 micromol/L), followed by cathepsin G and urokinase-type plasminogen activator, whereas that of the matrix metalloproteinases (MMPs) 2 and 9 showed an IC50 > 100 micromol/L. Nevertheless, inhibition of extracellular signal-regulated kinase 1/2 constitutive activity and reduction of MMP-2 and MMP-9 secretion was triggered by 0.5 micromol/L Hyp-DCHA to various degrees in different cell lines, the most in C-26. Inhibition of C-26 and HT-1080 cell chemoinvasion (80 and 54%, respectively) through reconstituted basement membrane was observed at these doses. Finally, in mice that received i.v. injections of C-26 or B16-LU8 cells, daily i.p. administration of Hyp-DCHA-without reaching tumor-cytotoxic blood levels-remarkably reduced inflammatory infiltration, neovascularization, lung weight (-48%), and size of experimental metastases with C-26 (-38%) and number of lung metastases with B16-LU8 (-22%), with preservation of apparently healthy and active behavior. These observations qualify Hyp-DCHA as an interesting lead compound to prevent and contrast cancer spread and metastatic growth.     

miRNA与肿瘤侵袭转移

目前,microRNA (miRNA)已成为肿瘤研究中最基本的参与者,主要通过与靶标基因3 'UTR(非翻译区)的完全或不完全配对,降解靶标基因mRNA或抑制其翻译,从而参与调控个体发育、细胞凋亡、增殖及分化等生命活动.miRNA作为调控基因表达的重要分子在肿瘤侵袭转移中的作用越来越受到重视,表明miRNA在肿瘤侵袭和转移中的作用机制具有重要的理论意义,同时也可为肿瘤的诊断和治疗提供新方法.本文就miRNA通过调控上皮间质转化及肿瘤干细胞导致肿瘤侵袭转移的最新研究进展作一综述.     

趋化因子与肿瘤侵袭转移

趋化因子是一类具有趋化作用的分泌型小分子蛋白质,其受体属于G蛋白偶联的7次跨膜受体超家族.越来越多的证据表明趋化因子与肿瘤生长、侵袭和转移密切相关.现综述趋化因子在肿瘤细胞增殖、迁移、粘附、降解细胞外基质、肿瘤血管生成及肿瘤器官特异性转移等过程中的作用.     

趋化因子与肿瘤侵袭转移

趋化因子是一类具有趋化作用的分泌型小分子蛋白质,其受体属于G蛋白偶联的7次跨膜受体超家族.越来越多的证据表明趋化因子与肿瘤生长、侵袭和转移密切相关.现综述趋化因子在肿瘤细胞增殖、迁移、粘附、降解细胞外基质、肿瘤血管生成及肿瘤器官特异性转移等过程中的作用.     

Tumor metastasis and cell adhesion molecules

The adhesive interaction between tumor cells, host cells or extracellular matrix (ECM) plays a crucial role in metastatic formation. We used synthetic polypeptide containing a repetitive core sequence, Arg-Gly-Asp (RGD), of cell-adhesive molecules; poly (RGD), to antagonize the adhesive interaction between ECM and integrin receptors on tumor cell surface during the metastatic cascade. Poly (RGD) significantly inhibited the experimental lung and liver metastasis as compared with RGD peptide when it was coinjected i.v. with different types of tumors. In a spontaneous lung metastasis model using B16-BL6 melanoma, multiple i.v. administrations of poly (RGD), before or after surgical excision of the primary tumor, resulted in significant reduction of the lung colonization. The mechanism responsible for the inhibition is partly associated with the ability to interfere with cell functions such as adhesiveness, motility, and invasiveness in the metastatic process. Poly (RGD) showed no cytotoxicity against host and tumor cells. Thus, the regulation of adhesive interaction of tumor cells with ECM or host cells by anti-adhesive polypeptides may provide a promising approach for the prevention of tumor metastasis.     

E-钙粘蛋白与肿瘤转移

钙粘蛋白是一组跨膜糖蛋白,主要参与同源细胞之间的连接,分为E、P和N三种。其中,E-钙粘蛋白主要分布在各种上皮细胞,E-钙粘蛋白具有抑制转移的作用,肿瘤细胞中E-钙粘蛋白基因的丢失,可导致细胞的侵袭和转移潜能的增加。本文就E-钙粘蛋白与肿瘤转移做简单综述。     

The role of the cell-cell adhesion molecule E-cadherin in large bowel tumour cell invasion and metastasis.

It has been suggested that the selective loss of E-cadherin expression can generate invasiveness in human carcinoma cells and might be a predictor of metastasis. Frozen sections of samples from 44 patients, 43 with suspected large bowel cancer and one with a liver recurrence were examined for E-cadherin expression using the antibody 6F9 specific for the human E-cadherin molecule. Twelve of the 40 patients with carcinoma already had lymph node involvement at the time of surgery. Samples from the primary carcinomas of only nine of these 12 patients showed reduced E-cadherin expression. However, the one lymph node with metastatic spread examined did show reduced E-cadherin expression. Four of the 40 carcinoma patients had liver involvement at the time of surgery. The primary carcinoma samples from only three of these four patients showed reduced E-cadherin expression. In addition only two out of the three liver metastases examined showed reduced expression. The primary carcinoma samples from seven patients with no evidence of tumour spread also exhibited reduced expression. Overall, analysis of the data suggests that there is no absolute correlation between reduced E-cadherin expression and tumour spread in carcinomas of the large bowel.