αvβ3, αvβ5 and αvβ6 integrins in brain metastases of lung cancer

Integrins are transmembranous adhesion molecules postulated to be involved in the brain metastatic cascade. We investigated the correlation of alpha v beta 3 (αvβ3), alpha v beta 5 (αvβ5) and alpha v beta 6 (αvβ6) integrin isoform expression with clinical characteristics including survival times in lung cancer patients with brain metastases (BM). All BM from lung cancer operated at our institution between 1990 and 2011, were identified; where available, primary tumors were retrieved as well. Immunohistochemical analysis for αvβ3, αvβ5 and αvβ6 integrin subunits was performed and correlated with Ki67 and hypoxia-inducible factor (HIF)-1α indexes. Clinical data including survival data were obtained by chart review. 191 BM specimens of 191 patients with histologically confirmed lung cancer (172 non-small cell lung cancer and 19 small cell lung cancer) were included. In 18 patients matched primary tumor samples were available. αvβ6 expression was commonly found on BM tumor cells (103/191; 53.9 %) and showed a significant association with low Ki67 proliferation indices (46 vs. 36 %, p = 0.001, Mann–Whitney U test) and favorable survival times (p = 0.020; log rank test) in patients with non-squamous NSCLC BM. αvβ5 expression was highly expressed on vascular structures (167/191; 87.4 %) and tumor stroma in BM (151/191; 79.1 %) and associated with high HIF-1α indices (60 vs. 90, p = 0.007, Mann–Whitney U test). αvβ3 expression was more frequently found on vascular structures in BM than in primary tumors (68.1 vs. 5.6 %; p = 0.645; Chi square test) and its expression in BM tumor cells correlated with low Ki67 indices (41 vs. 28 %; p = 0.046, Mann–Whitney U test). Expression of αv integrin subunits seem to be of pathobiological and clinical relevance in patients with NSCLC BM. Further investigations of their involvement in the brain metastatic cascade and their role as biomarkers are warranted.     

Fibrin improves beta (INS-1) cell function,proliferation and survival through integrin αvβ3

Extracellular matrix (ECM)–integrin stimulation can promote beta cell differentiation, proliferation and function. However, beta cells lose their insulin secretion function in response to glucose stimulation, and senesce when cultured with ECM proteins for a long time. Fibrin is a provisional ECM protein that is capable of maintaining beta cell function, yet the mechanisms by which this occurs is unknown. The present study examined how fibrin interacts with integrin receptors to promote beta cell cluster formation, proliferation and function. The rat insulinoma cell line, INS-1, was cultured on tissue-culture polystyrene, or with 2-D or 3-D fibrin gels for up to 4 weeks. Cells cultured with fibrin formed islet-like clusters and showed direct contacts with fibrin determined by scanning electron microscopy. Fibrin-cultured INS-1 cells also had significantly increased glucose-stimulated insulin secretion. A significant increase in integrin αvβ3 protein and phosphorylated FAK, Erk1/2 and Akt levels was observed in fibrin-cultured INS-1 cells, which was associated with significantly increased cell proliferation and decreased cell apoptosis. Integrin αvβ3 blockade affected INS-1 cell spreading on fibrin gels, and resulted in significantly decreased FAK phosphorylation and increased cleaved caspase-3 levels. These results show that fibrin promotes beta cell function, proliferation and survival via integrin αvβ3 interactions.     

Comparing the expression of integrins αvβ3, αvβ5, αvβ6, αvβ8, fibronectin and fibrinogen in human brain metastases and their corresponding primary tumors

Aims: To evaluate the expression of αv-series integrins in brain metastases. Inhibitors targeting these integrins are being tested for their therapeutic potential. Material and Method: The extracellular regions of the αvβ3, αvβ5, αvβ6, αvβ8, the cytoplasmic domain of β3, the αv-chain, and the ECM molecules fibronectin and fibrinogen were studied immunohistochemically in a series of 122 carcinoma and 60 melanomas metastatic to the central nervous system. In addition, 38 matched primary and metastatic tumors to the brain were compared directly. Results: The αv-subunit was generally moderately to highly expressed in most tumors. αvβ3 and cytoplasmic β3 were weakly to moderately detectable in metastatic renal cell carcinomas and melanomas, αvβ5 was prominently expressed in metastatic renal and colorectal carcinomas, αvβ6 was most abundantly detectable in metastatic lung adenocarcinomas, but absent in melanomas. The tumor associated vessels in CNS metastases consistently expressed αvβ3, αvβ5, αv-, fibronectin and fibrinogen, however, mostly at low levels, while αvβ6, αvβ8 were lacking in vasculature. The comparative analysis of 38 matched primary tumors and brain metastases showed comparable levels of expression only for αvβ3 and αvβ8, while αvβ6 and αvβ5 were higher in primaries. Conclusion: We confirmed that integrin expression exhibits considerable heterogeneity according to tumor origin. αvβ5 is the most promising target for integrin targeted treatment in brain metastases.     

Fibroblast expression of α-smooth muscle actin, α2β1 integrin and αvβ3 integrin: influence of surface rigidity

Open wound contraction necessitates cell and connective tissue interactions, that produce tension. Investigating fibroblast responses to tension utilizes collagen coated polyacrylamide gels with differences in stiffness. Human foreskin fibroblasts were plated on native type I collagen-coated polyacrylamide gel cover slips with different rigidities, which were controlled by bis-acrylamide concentrations. Changes in alpha smooth muscle actin (αSMA), α2β1 integrin (CD49B) and αvβ3 integrin (CD-51) were documented by immuno-histology and Western blot analysis. Cells plated on rigid gels were longer, and expressed αvβ3 integrin and αSMA within cytoplasmic stress fibers. In contrast, cells on flexible gels were shorter, expressed α2β1 integrin and had fine cytoskeletal microfilaments without αSMA. Increased tension changed the actin makeup of the cytoskeleton and the integrin expressed on the cell's surface. These in vitro findings are in agreement with the tension buildup as an open wound closes by wound contraction. It supports the notion that cells under minimal tension in early granulation tissue express α2β1 integrin, required for organizing fine collagen fibrils into thick collagen fibers. Thicker fibers create a rigid matrix, generating more tension. With increased tension cytoskeletal stress fibers develop that contain αSMA and αvβ3 integrin that replaces α2β1 integrin, consistent with cell switching from collagen to non-collagen proteins interactions.     

Phoyunnanin E inhibits migration of non-small cell lung cancer cells via suppression of epithelial-to-mesenchymal transition and integrin αv and integrin β3

Background

The conversion of the epithelial phenotype of cancer cells into cells with a mesenchymal phenotype-so-called epithelial–mesenchymal transition (EMT)-has been shown to enhance the capacity of the cells to disseminate throughout the body. EMT is therefore becoming a potential target for anti-cancer drug discovery. Here, we showed that phoyunnanin E, a compound isolated from Dendrobium venustum, possesses anti-migration activity and addressed its mechanism of action.

Methods

The cytotoxic and proliferative effects of phoyunnanin E on human non-small cell lung cancer-derived H460, H292, and A549 cells and human keratinocyte HaCaT cells were investigated by MTT assay. The effect of phoyunnanin E on EMT was evaluated by determining the colony formation and EMT markers. The migration and invasion of H460, H292, A549 and HaCaT cells was evaluated by wound healing assay and transwell invasion assay, respectively. EMT markers, integrins and migration-associated proteins were examined by western blot analysis.

Results

Phoyunnanin E at the concentrations of 5 and 10 μM, which are non-toxic to H460, H292, A549 and HaCaT cells showed good potential to inhibit the migratory activity of three types of human lung cancer cells. The anti-migration effect of phoyunnanin E was shown to relate to the suppressed EMT phenotypes, including growth in anchorage-independent condition, cell motility, and EMT-specific protein markers (N-cadherin, vimentin, slug, and snail). In addition to EMT suppression, we found that phoyunnanin E treatment with 5 and 10 μM could decrease the cellular level of integrin αv and integrin β3, these integrins are frequently up-regulated in highly metastatic tumor cells. We further characterized the regulatory proteins in cell migration and found that the cells treated with phoyunnanin E exhibited a significantly lower level of phosphorylated focal adhesion kinase (p-FAK) and phosphorylated ATP-dependent tyrosine kinase (p-AKT), and their downstream effectors (including Ras-related C3 botulinum (Rac-GTP); Cell division cycle 42 (Cdc42); and Ras homolog gene family, member A (Rho-GTP)) in comparison to those of the non-treated control.

Conclusions

We have determined for the first time that phoyunnanin E could inhibit the motility of lung cancer cells via the suppression of EMT and metastasis-related integrins. This new information could support further development of this compound for anti-metastasis approaches.

     

Is there a role for the tumor cell integrin αIIbβ3 and cytoskeleton in tumor cell-platelet interaction?

In vitro tumor cell-platelet interaction was examined using B16 amelanotic (B16a) melanoma cells. These tumor cells express the _IIb3-type cytoadhesin. Aggregation studies demonstrated that tumor cell surface _IIb3 mediates the recognition of platelets since pretreatment of tumor cells with antibody against _IIb3 prevents platelet-tumor cell interaction as well as platelet activation measured by aggregometry, platelet eicosanoid metabolism and ultrastructural analysis. In B16a cells, disruption of the microfilaments and intermediate filaments inhibits mobility of _IIb3 on the cell surface. Microtubules do not play a role in receptor mobility, because B16a cells do not possess well-defined microtubules in interphase and colchicine does not affect receptor mobility. Disruption of microfilaments or intermediate filaments results in an inhibition of tumor cell-platelet interaction as evidenced by aggregometry studies and ultrastructural analysis. We suggest that platelet interaction with tumor cells begins with _IIb3-mediated receptor recognition followed by not only platelet activation but also microfilament- and vimentin intermediate filament-dependent tumor cell activation.     

Chemokine receptor 7 promotes cell migration and adhesion in metastatic squamous cell carcinoma of the head and neck by activating integrin αvβ3

The mechanisms leading to squamous cell carcinoma of the head and neck (SCCHN) metastasis are incompletely understood. Although evidence shows that the chemokine receptor 7 (CCR7) and its ligand CCL19 may regulate tumor dissemination, their role in SCCHN is not clearly defined. CCR7 has been shown to regulate integrins, which facilitate adhesion of cancer cells to and/or migration through the extracellular matrix (ECM). To investigate the relationship between CCR7 and integrin αvβ3 in metastatic SCCHN, we used adhesion and migration assays, immunofluorescence staining and western blotting to determine whether integrin αvβ3 can be activated by CCL19 in the metastatic SCCHN cell line PCI-37B, which was pre-incubated with CCL19 or the integrin αvβ3 inhibitor, IS201. Our results demonstrate that CCR7 favors PCI-37B cell adhesion and migration, induces reorganization of the actin cytoskeleton and induces integrin αvβ3 phosphorylation. The integrin αvβ3 inhibitor, IS201, blocked all of these effects. CCR7 and integrin αvβ3 expression significantly and positively correlated with tumor size, clinical stage and nodal metastasis. Taken together, our data indicate that CCR7 regulates cell adhesion and migration via integrin αvβ3 in metastatic SCCHN. These results should provide the groundwork for new strategies aimed at preventing SCCHN metastasis.     

A multimodal nanoparticle-based cancer imaging probe simultaneously targeting nucleolin, integrin αvβ3 and tenascin-C proteins

Molecular imaging of cancers has been characterized based on the sensitivity and selectivity of a single cancer probe targeting a cancer biomarker of a specific cancer cell line. Here, we designed a multimodal nanoparticle-based Simultaneously Multiple Aptamers and RGD Targeting (SMART) cancer probe targeting multiple cancer biomarkers to enhance the specificity and signal sensitivity for various cancers. Transmission electron microscopy revealed that the multimodal SMART cancer probe was spheric and well dispersed. Fluorescence, radioisotope, and magnetic resonance analysis demonstrated that the SMART cancer probe simultaneously targeting the nucleolin, integrin α(v)β(3) and Tnc proteins had dramatically enhanced specificity and signal intensity when used to target cancers from C6, NPA, DU145, HeLa and A549 cells when compared with single cancer probes conjugated with AS1411, RGD or TTA1 targeting a single cancer biomarker. The results demonstrated that the SMART cancer probe will be useful for the diagnosis of different cancers as a cancer master probe.     

Integrin α3β1 regulates tumor cell responses to stromal cells and can function to suppress prostate cancer metastatic colonization

Integrin α3β1 promotes tumor cell adhesion, migration, and invasion on laminin isoforms, and several clinical studies have indicated a correlation between increased tumoral α3β1 integrin expression and tumor progression, metastasis, and poor patient outcomes. However, several other clinical and experimental studies have suggested that α3β1 can possess anti-metastatic activity in certain settings. To help define the range of α3β1 functions in tumor cells in vivo, we used RNAi to silence the α3 integrin subunit in an aggressive, in vivo-passaged subline of PC-3 prostate carcinoma cells. Loss of α3 integrin impaired adhesion and proliferation on the α3β1 integrin ligand, laminin-332 in vitro. Despite these deficits in vitro, the α3-silenced cells were significantly more aggressive in a lung colonization model in vivo, with a substantially increased rate of tumor growth that significantly reduced survival. In contrast, silencing the related α6 integrin subunit delayed metastatic growth in vivo. The increased colonization of α3-silenced tumor cells in vivo was recapitulated in 3D collagen co-cultures with lung fibroblasts or pre-osteoblast-like cells, where α3-silenced cells showed dramatically enhanced growth. The increased response of α3-silenced tumor cells to stromal cells in co-culture could be reproduced by fibroblast conditioned medium, which contains one or more heparin-binding factors that selectively favor the growth of α3-silenced cells. Our new data suggest a scenario in which α3β1 regulates tumor–host interactions within the metastatic tumor microenvironment to limit growth, providing some of the first direct evidence that specific loss of α3 function in tumor cells can have pro-metastatic consequences in vivo.     

An improved method for the quantitation of cellular migration: Role of αvβ3 integrin in endothelial and smooth muscle cell migration

The present study was undertaken to develop a simple and improvedmethod for the accurate quantitation of cellular migration and to examinethe role of v3 integrins in different cellular migration. Usingour newly developed micro-volume chemotaxis assay, we developed an improvedquantitative method to measure in vitro chemotaxis of smooth muscle orendothelial cells toward different extracellular matrix proteins. Theconvenience in setup and counting of migrated cells using this methodallows for large capacity screening and for various research applicationswith other cells as well. The signal. to noise ratios were in the range of10/1, along with about 10–20% intra- or inter-assayvariabilities. Using this method, we have determined that eithervitronectin at 0.4 µg/well or osteopontin at 0.4 µg/well areselective v3 chemoattractants for endothelial or smooth musclecells (0.5 × 105 cells/well). Additionally, a selective v3small molecule peptiddomimetic, monoclonal antibody LM609, or an anti-3 (v3/II3) anti-body, c7E3 demonstratedmaximal inhibition of cellular migration toward vitronectin or osteopontin.These data suggest the potential utility of this method in assessing therole of various mechanisms in cellular migration and also suggests the potential implication of an v3 antagonist in blocking pathologicalprocesses involving endothelial or smooth muscle cell adhesion/migration.     

Association of CD98, integrin β1, integrin β3 and Fak with the progression and liver metastases of colorectal cancer

CD98-mediated β1 and β3 integrins activation can induce Fak phosphorylation which eventually promotes cell survival, proliferation, and migration. We evaluated the expression of CD98, integrin β1, integrin β3 and Fak in 45 cases of matched colorectal cancer (CRC) and liver metastases as well as 35 cases of CRC without liver metastases.     

Elevated expression of integrin αv and β5 subunit in laryngeal squamous-cell carcinoma associated with lymphatic metastasis and angiogenesis

In the past several years, the αv integrin subfamily has been repeatedly found to be involved in tumor progression and angiogenesis. The aim of this study was to investigate the expression of the integrin αv subfamily in laryngeal squamous cell carcinoma (LSCC), and to correlate the expression rate with tumor biological behavior and angiogenesis of the LSCC. The integrin αv subfamily, including αv, β1, β3, β5, β6 and β8 subunits, was immunohistochemically found to be expressed in 64 patients with LSCC, and we analyzed the relationship between the expression rate and the clinicopathological stage of this cancer. Immunohistochemical staining for CD105 was carried out in the same group of the patients. The intratumoral microvessel density (IMVD) of the LSCC was calculated by CD105 staining, and the correlation between the IMVD and αv subfamily expression was discussed. The results showed that all members of the integrin αv subfamily could be detected in the LSCC. The expression rate of integrin αv and β5 subunits in primary cancer was significantly higher than in normal tissue, and their expression rate in the group with lymphatic metastasis was significantly higher than in the group without metastasis. The IMVD of the group with positive expression of αv and β5 subunits was significantly higher than in the group with negative expression, but there were no significant effects on the β1, β3, β6 and β8 subunits in these biological processes. In conclusion, the expressions of integrin αv and β5 subunits were significantly associated with lymphatic metastasis and angiogenesis of the LSCC. Among the members of integrin αv subfamily, integrin αvβ5 might play an important role in invasion and metastases of the LSCC, and it may become a valuable marker for the evolution of the LSCC.     

HOXD3-overexpression increases integrin αvβ3 expression and deprives E-cadherin while it enhances cell motility in A549 cells

We have previously shown that transduction of HOXD3, one of homeobox genes, into human lung cancer A549 cells enhances cell motility, invasion and metastasis. In the present study, we examined the roles of integrin β3 which was up-regulated by HOXD3-overexpression in the HOXD3-induced motility of A549 cells. We first established integrin β3-transfectants and compared their motile activity to those of the HOXD3-transfected, control-transfected and parental cells by three different assays. The integrin β3-transfectants as well as the HOXD3-transfectants formed heterodimer with integrin αv subunit, and showed highly motile activities assessed by haptotaxis or phagokinetic track assay compared to the control transfectants or parental cells. In vitro wound-healing assay revealed that migratory activities were graded as the HOXD3-transfectants > the integrin β3-transfectants > the control transfectants or parental cells. E-cadherin was expressed in the integrin β3-transfectants but not expressed in the HOXD3-transfectants. An addition of function-blocking antibody to E-cadherin into the wound-healing assay promoted the migratory activity of the integrin β3-transfectants, suggesting that E-cadherin prevented the cells from dissociating from the wound edges. These results indicate that increased expression of integrin αv β3 and loss of E-cadherin by HOXD3-overexpression are responsible for the enhanced motility and dissociation.     

RGD-mutants of B-lymphotropic polyomavirus capsids specifically bind to αvβ3 integrin

Summary. Integrins are a family of cell surface proteins that function as receptors for extracellular matrix ligands and for some viruses. A subset of integrins recognises peptide sequences containing arginine-glycine-aspartic acid (RGD) motifs as ligands. The B-lymphotropic polyomavirus (LPV) has a non-enveloped capsid that recognises a sialylated cell surface receptor. To change the receptor binding specificity we have replaced sets of three amino acids in three predicted surface loops of the major capsid protein VP1 of the B-lymphotropic polyomavirus LPV by RGD.Ten mutants gave rise to the expected 40kDa VP1 protein upon expression from a baculovirus vector in insect cells. Five of the VP1 mutants representing all three surface loops have retained the ability to spontaneously assemble to capsids in the nuclei of the insect cells. Structural changes of the mutant capsid surface were shown by differential reactivity with a set of 7 neutralising monoclonal antibodies that recognise conformational surface epitopes of wildtype LPV virions. In addition all mutant capsids had lost specific binding to the LPV receptor.Three mutant capsids of one loop (BC) showed specific binding to v3 integrin but not to integrins v5, v6, or to IIb3 known also to recognise RGD containing peptide sequences. This selective binding of the mutant capsids could be inhibited by synthetic peptides that specifically bind to v3 integrin with IC₅₀ values between 10 and 40nM.     

Distribution of thrombospondin and integrin αv in DCIS,invasive ductal and lobular human breast carcinomas

The ultrastructural distribution of thrombospondin (TSP) and its cell surface receptor, integrin _v, was studied in two cases of human breast carcinoma: one of ductal carcinoma in situ (DCIS) with an invasive component, and one of invasive lobular carcinoma. In DCIS, moderate immunolabelling for TSP and integrin _v was observed in the rough endoplasmic reticulum and at the plasma membrane of intraductal carcinoma cells. TSP was also associated with extracellular matrix collagen fibrils surrounding in situ carcinoma cells. In the invasive part of this ductal carcinoma, most of the malignant cells were negative for TSP, while integrin _v was moderately expressed in these cells. In sharp contrast, typical strands of invasive lobular carcinoma cells in Indian file showed moderate TSP immunostaining in the rough endoplasmic reticulum and strong immunoreactivity for TSP at the plasma membrane and in the extracellular matrix. Moderate to strong immunoreactivity for integrin _v was also observed in invasive lobular carcinoma cells. Because of the role of TSP during cancer cell invasion, the different expression patterns of TSP in invasive ductal versus lobular carcinoma may well reflect biological differences between these two types of breast carcinoma and could account for the peculiar diffuse invasive behaviour of breast lobular carcinoma cells.This work was supported by grants from the Fédération Nationale des Groupements des Entreprises Françaises dans la Lutte contre le Cancer (P.C.), the Association pour la Recherche sur le Cancer (L.F.), and the Ligue contre le Cancer de la Drôme (L.F.)     

A d-amino acid containing peptide as a potent,noncovalent inhibitor of α5β1 integrin in human prostate cancer invasion and lung colonization

Primary tumors often give rise to disseminated tumor cells (DTC’s), which acquire full malignancy after invading distant site(s). Thus, DTC’s may be a productive target for preventing prostate cancer metastasis progression. Our prior research showed that PHSCN peptide (Ac-PHSCN-NH₂) targets activated α5β1 integrin to prevent invasion and metastasis in preclinical adenocarcinoma models, and disease progression in Phase I clinical trial. Here, we report that d-stereoisomer replacement of histidine and cysteine in PHSCN produces a highly potent derivative, Ac-PhScN-NH₂ (PhScN). PhScN was 27,000- to 150,000-fold more potent as an inhibitor of basement membrane invasion by DU 145 and PC-3 prostate cancer cells. A large increase in invasion–inhibitory potency occurred after covalent modification of the sulfhydryl group in PHSCN to prevent disulfide bond formation; while the potency of covalently modified PhScN was not significantly increased. Thus PhScN and PHSCN invasion inhibition occurs by a noncovalent mechanism. These peptides also displayed similar cell surface binding dissociation constants (K_d), and competed for the same site. Consistent with its increased invasion–inhibitory potency, PhScN was also a highly potent inhibitor of lung extravasation and colonization in athymic nude mice: it was several hundred- or several thousand-fold more potent than PHSCN at blocking extravasation by PC-3 or DU 145 cells, and 111,000- or 379,000-fold more potent at inhibiting lung colonization, respectively. Furthermore, systemic 5 mg/kg PhScN monotherapy was sufficient to cause complete regression of established, intramuscular DU 145 tumors. PhScN thus represents a potent new family of therapeutic agents targeting metastasis by DTC’s to prevent parallel progression in prostate cancer.     

A near-infrared phthalocyanine dye-labeled agent for integrin αvβ6-targeted theranostics of pancreatic cancer

Integrin αvβ6 is widely upregulated in variant malignant cancers but is undetectable in normal organs, making it a promising target for cancer diagnostic imaging and therapy. Using streptavidin-biotin chemistry, we synthesized an integrin αvβ6-targeted near-infrared phthalocyanine dye-labeled agent, termed Dye-SA-B-HK, and investigated whether it could be used for cancer imaging, optical imaging-guided surgery, and phototherapy in pancreatic cancer mouse models. Dye-SA-B-HK specifically bound to integrin αvβ6 in vitro and in vivo with high receptor binding affinity. Using small-animal optical imaging, we detected subcutaneous and orthotopic BxPC-3 human pancreatic cancer xenografts in vivo. Upon optical image-guidance, the orthotopically growing pancreatic cancer lesions could be successfully removed by surgery. Using light irradiation, Dye-SA-B-HK manifested remarkable antitumor effects both in vitro and in vivo. ¹⁸F-FDG positron emission tomography (PET) imaging and ex vivo fluorescence staining validated the observed decrease in proliferation of treated tumors by Dye-DA-B-HK phototherapy. Tissue microarray results revealed overexpression of integrin αvβ6 in over 95% cases of human pancreatic cancer, indicating that theranostic application of Dye-DA-B-HK has clear translational potential. Overall, the results of this study demonstrated that integrin αvβ6-specific Dye-SA-B-HK is a promising theranostic agent for the management of pancreatic cancer.     

Expression and clinical significance of CD151 and integrin α3β1 in colorectal tumors

目的:探讨CD151和整合素α3β1在直肠腺瘤及结直肠腺癌组织中的表达及其与临床各个病理因素之间的关系,并且研究两者的相关性.方法:应用免疫组织化学双染方法对正常结直肠黏膜、结直肠腺瘤及结直肠腺癌组织各120例进行CD151和整合素α3β1检测,并进行Kaplan-Meier生存分析.采用Spearman等级相关分析CD151和整合素αβ1之间的相关性.结果:CD151结直肠正常黏膜、腺瘤、腺癌组织的阳性率分别为21.7％、52.5％、72％,腺瘤和腺癌组织分别与正常黏膜比较均具有统计学意义.整合素α3β1在结直肠正常黏膜、腺瘤、腺癌组织的阳性率分别为34.2％、55％、70％,腺瘤和腺癌组织分别与正常黏膜比较均具有统计学意义.在结直肠腺癌中,CD151和整合素α3β1的表达与患者年龄、性别和肿瘤的部位、大小无相关性,与肿瘤的分化程度、浸润深度、淋巴结转移及Duke's分期有关.CD151和整合素α3β1在大肠正常黏膜、腺瘤及腺癌组织中的表达经双变量相关分析,表达呈正相关.从图的Kaplan-Meier生存曲线及Log-Rank检验可知,CD151+、α3β1+、CD151+α3β1+与大肠癌患者5年生存期密切相关,是影响大肠癌预后的因素.结论:CD151和整合素α3β1在大肠癌的表达密切相关,提示CD151与整合素α3β1复合物存在于大肠癌,其表达对预后产生明显的影响.CD151与整合素α3β1联合表达是临床预后判断的可靠指标.     

Regulation of melanoma cell migration and invasion by laminin-5 and α3β1 integrin (VLA-3)

We evaluated the role of soluble factors produced from epidermal cells in melanoma cell motility by using the Boyden chamber chemoinvasion system. The migration of two melanoma cell lines, A375 and Mewo, was potentiated by conditioned media of A431 epidermoid cells in a concentration-dependent manner. The enhancement of A375 melanoma cell motility induced by the conditioned medium was blocked by antibodies against either α3 or β1 integrin subunit. The motility-stimulating activity was recovered in the same fraction as the α3 integrin-dependent adhesion-promoting activity in a high-molecular-weight (>200 kDa) fraction on Superose 12 gel chromatography, and adsorbed with an anti-laminin-5 antibody. Purified laminin-5 was capable of potentiating melanoma cell migration as measured in either the chemotaxis assay with a soluble form of laminin-5 or the haptotaxis assay with membranes coated with a mixture of laminin-5 and Matrigel. Furthermore, immobilized laminin-5 induced A375 melanoma cells to secrete matrix metalloproteinase-9 (type IV collagenase) into the culture medium. These results strongly suggest that the interaction of laminin-5 produced in the epidermis with α3β1 integrin on melanoma cells is involved in cell migration, invasion, and degradation of extracellular matrix proteins. This revised version was published online in July 2006 with corrections to the Cover Date.