Β1 Integrin Expression Levels Research Articles

Expression levels of β1, β3 integrins and MMP2 and features of morphological heterogeneity of pancreatic ductal adenocarcinoma associated with distant metastasis

Background. Pancreatic cancer is characterized by pronounced invasive growth and a high tendency to lymphogenous and hematogenous metastasis. Molecular mechanisms underlying the epithelial-mesenchymal transition, in particular, changes in the expression of β1, β3 integrins and MMP2, contribute to the invasion and metastasis of pancreatic cancer. A phenotypic manifestation of invasive potential of pancreatic cancer may be the heterogeneity of the morphological structure of the parenchymal component of ductal adenocarcinoma.The aim of the study was to analyze the expression levels of β1 integrin, β3 integrin, MMP2 and the morphological heterogeneity in the tissue of pancreatic ductal adenocarcinoma, as well as to compare the data obtained with distant metastasis.Material and Methods. The study group included 84 patients with morphologically verifed pancreatic ductal adenocarcinoma (T1–4N0–2M0–1). The median age of the patients was 58.6 ± 9.1 years. All patients underwent surgery, during which an incisional biopsy of the primary tumor tissue was performed. Expression of integrin β1, integrin β3, and MMP2 markers was assessed by immunohistochemistry.Results. The positive expression of β3 integrin in glandular, trabecular, and solid structures was observed more frequently in patients with hematogenous metastases than in patients without distant metastases (87 vs 12 %, р=0.001; 100 vs 22 %, р=0.004; 100 vs 8 %, р=0.001, respectively). The positive expression of MMP2 in glandular and solid structures was also observed more often in patients with hematogenous metastases than in patients without distant metastases (87 vs 32 %, р=0.001 and 100 vs 27 %, р=0.001, respectively). The positive expression of integrin β1 in glandular, trabecular, solid structures and tumor cells was observed less frequently in patients with hematogenous metastases than in patients without distant metastases (27 vs 86 %, р=0.001; 25 vs 79 %, р=0.007; 0 vs 93 %, р=0.001 and 18 vs 60 %, respectively). The logistic regression model for predicting the risk of hematogenous metastasis of pancreatic ductal adenocarcinoma was developed: Y=(-6.71 + 30.9×X1 – 27.2×X2), where X1 – the presence or absence of β3 integrin expression in the cells of the glandular structures, X2 – the presence or absence of MMP2 in the cells of the glandular structures. The risk of developing hematogenous metastasis was determined by the formula: Р=еY/(1+еY). Model confdence interval: χ2 =34.0; p<0.001, sensitivity: 89 %, specifcity: 87 %. Conclusion. Expression of integrin β1, integrin β3, and MMP2 markers in various structures of the parenchymal component of pancreatic ductal adenocarcinoma is associated with distant metastasis. The localization of the expression of the studied markers in the glandular structures of tumor tissue is of particular importance. The presence of positive expression of integrin β3 and MMP2 in almost all types of tumor structures is associated with the highest frequency of distant dissemination. Key words: ductal pancreatic adenocarcinoma, β1 integrin, β3 integrin, MMP2, tumor morphological heterogeneity, distant metastases> ˂ 0.001, sensitivity: 89 %, specifcity: 87 %.Conclusion. Expression of integrin β1, integrin β3, and MMP2 markers in various structures of the parenchymal component of pancreatic ductal adenocarcinoma is associated with distant metastasis. The localization of the expression of the studied markers in the glandular structures of tumor tissue is of particular importance. The presence of positive expression of integrin β3 and MMP2 in almost all types of tumor structures is associated with the highest frequency of distant dissemination.

Calreticulin Regulates β1-Integrin mRNA Stability in PC-3 Prostate Cancer Cells.

Prostate cancer (PCa) is the major cause of cancer-related death among aging men worldwide. Recent studies have suggested that calreticulin (CRT), a multifunctional chaperon protein, may play an important role in the regulation of PCa tumorigenesis and progression. However, the underlying mechanisms are still unclear. Integrin is an important regulator of cancer metastasis. Our previous study demonstrated that in J82 bladder cancer cells, CRT affects integrin activity through FUBP-1-FUT-1-dependent fucosylation, rather than directly affecting the expression of β1-integrin itself. However, whether this regulatory mechanism is conserved among different cell types remains to be determined. Herein, we attempted to determine the effects of CRT on β1-integrin in human prostate cancer PC-3 cells. CRT expression was suppressed in PC-3 cells through siRNA treatment, and then the expression levels of FUT-1 and β1-integrin were monitored through RT-PCR. We found that knockdown of CRT expression in PC-3 cells significantly affected the expression of β1-integrin itself. In addition, the lower expression level of β1-integrin was due to affecting the mRNA stability. In contrast, FUT-1 expression level was not affected by knockdown of CRT. These results strongly suggested that CRT regulates cellular behavior differently in different cell types. We further confirmed that CRT directly binds to the 3′UTR of β1-integrin mRNA by EMSA and therefore affects its stability. The suppression of CRT expression also affects PC-3 cell adhesion to type I collagen substrate. In addition, the levels of total and activated β1-integrin expressed on cell surface were both significantly suppressed by CRT knockdown. Furthermore, the intracellular distribution of β1-integrin was also affected by lowering the expression of CRT. This change in distribution is not lysosomal nor proteosomal pathway-dependent. The treatment of fucosydase significantly affected the activation of surface β1-integrin, which is conserved among different cell types. These results suggested that CRT affects the expression of β1-integrin through distinct regulatory mechanisms.

Epithelial-mesenchymal transition and metastatic ability of CD133+ colorectal cancer stem-like cells under hypoxia.

Although CD133 is a representative cancer stem cell marker, its function in tumor aggressiveness under hypoxia remains unclear. Therefore, the present study aimed to investigate the associations between CD133, the epithelial-mesenchymal transition and distant metastasis in colorectal cancer. CD133+ and CD133− cells were isolated from a single colorectal cancer cell line LoVo, and their adhesive and migratory properties were compared under hypoxic conditions. Immunostaining analysis was performed to determine CD133 expression in clinical samples of primary tumors, as well as liver and peritoneal metastases. Under hypoxia, the expression levels of hypoxia-inducible factor (HIF)-1α and the epithelial-mesenchymal transition markers N-cadherin and vimentin were significantly higher in the CD133+ compared with those in the CD133− cells. Furthermore, the migratory ability of the CD133+ cells was higher compared with that of the CD133− cells under hypoxia. By contrast, the expression levels of β1 integrin were significantly lower in the CD133+ cells under hypoxia compared with those in the CD133− cells. Immunohistochemical analysis of clinical samples revealed that the levels of CD133 expression in metastatic tissues from the liver were significantly higher compared with those in the corresponding primary tumors, whereas CD133 expression levels in peritoneal metastatic tissues were significantly lower compared with those in the corresponding primary tumors. In conclusion, compared with the CD133− cells, the CD133+ colorectal cancer cells exhibited enhanced levels of HIF-1α expression and tumor cell migration during hypoxia. This was associated with an increased ability of epithelial-mesenchymal transition, possibly leading to the acquisition of an increased hematogenous metastatic potential and eventually resulting in liver metastasis. High β1 integrin expression levels in the CD133− cells under hypoxia may serve a key role in cell adhesion to the peritoneum, resulting in peritoneal metastasis.

Triple PLGA/PCL Scaffold Modification Including Silver Impregnation, Collagen Coating, and Electrospinning Significantly Improve Biocompatibility, Antimicrobial, and Osteogenic Properties for Orofacial Tissue Regeneration.

Biodegradable synthetic scaffolds hold great promise for oral and craniofacial guided tissue regeneration and bone regeneration. To overcome the limitations of current scaffold materials in terms of osteogenic and antimicrobial properties, we have developed a novel silver-modified/collagen-coated electrospun poly-lactic-co-glycolic acid/polycaprolactone (PLGA/PCL) scaffold (PP-pDA-Ag-COL) with improved antimicrobial and osteogenic properties. Our novel scaffold was generated by electrospinning a basic PLGA/PCL matrix, followed by silver nanoparticles (AgNPs) impregnation via in situ reduction, polydopamine coating, and then coating by collagen I. The three intermediate materials involved in the fabrication of our scaffolds, namely, PLGA/PCL (PP), PLGA/PCL-polydopamine (PP-pDA), and PLGA/PCL-polydopamine-Ag (PP-pDA-Ag), were used as control scaffolds. Scanning electron micrographs and mechanical testing indicated that the unique three-dimensional structures with randomly oriented nanofibrous electrospun scaffold architectures, the elasticity modulus, and the tensile strength were maintained after modifications. CCK-8 cell proliferation analysis demonstrated that the PP-pDA-Ag-COL scaffold was associated with higher MC3T3 proliferation rates than the three control scaffolds employed. Scanning electron and fluorescence light microscopy illustrated that PP-pDA-Ag-COL scaffolds significantly enhanced MC3T3 cell adhesion compared to the control scaffolds after 12 and 24 h culture, in tandem with the highest β1 integrin expression levels, both at the mRNA level and the protein level. Alkaline phosphatase activity, BMP2, and RUNX2 expression levels of MC3T3 cells cultured on PP-pDA-Ag-COL scaffolds for 7 and 14 days were also significantly higher when compared to controls (P < 0.001). There was a wider antibacterial zone associated in PP-pDA-Ag-COL and PP-pDA-Ag scaffolds versus control scaffolds (P < 0.05), and bacterial fluorescence was reduced on the Ag-modified scaffolds after 24 h inoculation against Staphylococcus aureus and Streptococcus mutans. In a mouse periodontal disease model, the PP-pDA-Ag-COL scaffold enhanced alveolar bone regeneration (31.8%) and was effective for periodontitis treatment. These results demonstrate that our novel PP-pDA-Ag-COL scaffold enhanced biocompatibility and osteogenic and antibacterial properties and has therapeutic potential for alveolar/craniofacial bone regeneration.

Semaphorin 7a participants in pterygium by regulating vascular endothelial growth factor.

To investigate the relationship between semaphorin 7a expression and cell proliferation and migration in pterygium fibroblasts. Twenty-six patients with surgically diagnosed pterygium were enrolled, including 15 cases of primary pterygium and 11 cases of recurrent pterygium. In addition, 12 cases of normal conjunctival tissue were collected. The expression of semaphorin 7a in normal conjunctival tissue, primary pterygium and recurrent pterygium was detected by real-time polymerase chain reaction. Recurrent pterygium fibroblasts were isolated and cultured, and the expression of semaphorin 7a was silenced by small interfering RNA (siRNA) interference technique. Furthermore, the effects of si-semaphorin 7a interference on the mRNA and protein levels of β1-integrin, vascular endothelial growth factor A (VEGFA) and vascular endothelial growth factor receptor (VEGFR), and on fibroblast proliferation were analyzed. Transwell assay was used to detect the effect of semaphorin 7a interference on fibroblast migration. Semaphorin 7a was highly expressed in the primary pterygium and recurrent pterygium samples than that of the normal conjunctival tissue. Compared with the primary pterygium, the expression of semaphoring 7a in the recurrent pterygium samples was significantly increased (P<0.05). The mRNA and protein expression levels of β1-integrin, VEGFA and VEGFR were decreased after si-semaphorin 7a transfection, and as well as the cell proliferation and migration. Semaphorin 7a might play important roles in the pathogenesis of pterygium by affecting the expression of β1-integrin, VEGFA and VEGFR.

Investigation of protective mechanisms of Atorvastatin against high glucose environment-induced injuries of myocardial microvascular endothelial cells

Objective To investigate the protective mechanisms of Atorvastatin against high glucose environment-induced injuries of myocardial microvascular endothelial cells. Methods Myocardial microvascular endothelial cells(MMECs)in SD rat were cultured and divided into groups of control group, hyperglycemia group, atorvastatin group, and atorvastatin + high glucose group.The level of reactive oxygen species(ROS)was assayed using Superoxide Assay Kit.Apoptosis of cells was detected by terminal deoxynucleotidyl transferase(TdT)-mediated dUTP nick end labeling(TUNEL). The expression levels of Akt1 and β1-Integrin were assayed by short-interfering RNA(siRNA)technique, and the levels of small GTP-binding protein dissociation stimulator(SmgGDS) expression were measured using Western blot. Results (1)The level of ROS was higher in the high glucose group than in the control group(t=4.154, P <0.01), and lower in both Atorvastatin group and the Atorvastatin + high glucose group than in the high glucose group(t=4.233 and 2.893, both P <0.05). (2)The proportion of apoptotic cells was higher in the high glucose group than in the control group(t=4.058, P <0.01), and lower in both Atorvastatin group and the Atorvastatin + high glucose group than in the high glucose group(t=4.157 and 2.601, both P<0.05). (3)The expression level of Akt1 was lower in the high glucose group and the high glucose + Atorvastatin group than in the mock control group after transfection of Akt1-siRNA(t=4.058 and 4.167, both P<0.01). The expression level of β1-integrin was lower in the high glucose group and the high glucose + atorvastatin group than in the mock control group after transfection of β1-integrin-siRNA(t=4.073 and 4.215, both P<0.01). (4)Western blot analysis showed the following results.First, the relative expression levels of SmgGDS in both the low dose(1 μmol/L)and high dose(10 μmol/L)of atorvastatin group were higher than in the control group(t=2.671 and 2.832, both P <0.05). Second, the relative expression level of SmgGDS in the high dose group were higher than in the low dose group(t=2.612, P<0.05). Third, after transfection of Akt1-siRNA, the expression level of SmgGDS in the high glucose + Atorvastatin group and the high glucose group was decreased; and the level was higher in the high glucose + atorvastatin + mock group than in the high glucose + mock group(t=4.051, P<0.01). Fourth, after transfection of β1-integrin-siRNA, the expression level of SmgGDS was lower in high glucose + Atorvastatin group and the high glucose group than in the high glucose + Atorvastatin + mock group; the level was higher in the high glucose + Atorvastatin + mock group than in the high glucose + mock group(t=4.068, P <0.01). Fifth, the expression level of Akt phosphorylation in the high glucose group and the high glucose + Atorvastatin group was higher at 10 minutes than at five minutes(t=2.608, P<0.05), and higher at 15 minutes than at 10 minutes(t=3.127, P <0.05). After transfection of β1-integrin-siRNA, the expression level of p-Akt / t-Akt was lower in the high glucose group than in the high glucose + mock group(t=3.371, P <0.05). Conclusions Atorvastatin treatment protects myocardial microvascular endothelial cells possibly by up-regulating SmgGDS through β1-integrin/Akt1 against high glucose environment-induced oxidative stress and apoptosis injuries. Key words: Atorvastatin; Glucose, high; Myocardium; Endothelial cells; Integrin beta1; Small GTP-binding protein dissociation stimulator

Granulocyte colony-stimulating factor (G-CSF) upregulates β1 integrin and increases migration of human trophoblast Swan 71 cells via PI3K and MAPK activation

Multiple cytokines and growth factors expressed at the fetal-maternal interface are involved in the regulation of trophoblast functions and placental growth, but the role of G-CSF has not been completely established. Based on our previous study showing that G-CSF increases the activity of matrix metalloproteinase-2 and the release of vascular endothelial growth factor in Swan 71 human trophoblast cells, in this work we explore the possible contribution of G-CSF to cell migration and the G-CSF-triggered signaling pathway. We found that G-CSF induced morphological changes on actin cytoskeleton consistent with a migratory cell phenotype. G-CSF also up-regulated the expression levels of β1 integrin and promoted Swan 71 cell migration. By using selective pharmacological inhibitors and dominant negative mutants we showed that PI3K, Erk 1/2 and p38 pathways are required for promoting Swan 71 cell motility. It was also demonstrated that PI3K behaved as an upstream regulator of Erk 1/2 and p38 MAPK. In addition, the increase of β1 integrin expression was dependent on PI3K activation. In conclusion, our results indicate that G-CSF stimulates β1 integrin expression and Swan 71 cell migration by activating PI3K and MAPK signaling pathways, suggesting that G-CSF should be considered as an additional regulatory factor that contributes to a successful embryo implantation and to the placenta development.

High-level β1-integrin expression in a subpopulation of highly tumorigenic oral cancer cells

The β1 integrin (CD29) is a putative marker for cancerous epithelial stem cells. Cancer stem cells are essential to drive tumor growth, recurrence, and metastasis. We investigated the role of β1-integrin expression in the development of malignant phenotypes of oral squamous cell carcinoma (OSCC). Immunostaining was used to analyze the expression levels of β1 integrins in different types of cell colonies and tumor spheres. The results of cell viability and migration assays with and without siRNA knockdown of β1-integrin expression were compared. Cells expressing β1 integrins were evaluated for their tumorigenicity in mice. The expression of β1 integrins in human specimens of oral cancers at different clinical stages was semiquantified based on immunohistochemical staining of the β1-integrin protein. The expression level of β1 integrins in Meng-1 oral epidermoid carcinoma cells (OECM-1) cells was significantly higher in holoclonal colonies and tumor spheres compared to control cells. The knockdown of β1-integrin expression in OECM-1 cells reduced cell proliferation, migration, and tumor sphere formation. Beta-1 integrin (+) cells were more tumorigenic in the mouse xenograft model than β1 integrin (-) cells. In the human specimens, the expression level of the β1-integrin protein positively correlated with the clinical stage. The expression of β1 integrin in OECM-1 cells is involved in the development of malignant phenotypes of OSCC. Inhibitors for β1-integrin signaling may be suitable to become target-specific therapies for OSCC.

Proper cerebellar development requires expression of β1‐integrin in Bergmann glia, but not in granule neurons

β1-class integrins play essential roles both in developmental biology as well as in cancer. Particularly, a Nestin-driven deletion of β1-integrin receptors results in severe abnormalities of brain development including a laminar disorganization of cerebellar granule neurons. However, since Nestin is expressed in all kinds of neural precursors, these data do not allow conclusions to be drawn about the role of β1-integrins in distinct neuronal and glial cell types. By generating conditional knockout mice using granule cell-specific Math1-promoter sequences, we show here that the expression of β1-integrins in granule neurons is dispensable for the development of the cerebellum. Also, deletion of β1-integrin from tumors that arise in a mouse model of granule cell precursor-derived medulloblastoma did not result in a significant survival benefit. Last, expression levels of β1-integrin in human medulloblastoma samples did not predict patient's outcome. However, a β1-integrin knockout using hGFAP-promoter sequences led to cerebellar hypoplasia, inappropriate positioning of Bergmann glia cells in the molecular layer, undirected outgrowth of radial glia fibers, and granule cell ectopia. We therefore conclude that β1-integrin expression in cerebellar granule neurons is not essential during normal development or medulloblastoma formation. In fact, it is the expression of β1-integrin in glia that is crucial for the proper development of the cerebellar cortex.

Involvement of β1-Integrin Up-regulation in Basic Fibroblast Growth Factor- and Epidermal Growth Factor-induced Proliferation of Mouse Neuroepithelial Cells

In neural stem cells, basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) promote cell proliferation and self-renewal. In the bFGF- and EGF-responsive neural stem cells, beta1-integrin also plays important roles in crucial cellular processes, including proliferation, migration, and apoptosis. The cross-talk of the signaling pathways mediated by these growth factors and beta1-integrin, however, has not been fully elucidated. Here we report a novel molecular mechanism through which bFGF or EGF promotes the proliferation of mouse neuroepithelial cells (NECs). In the NECs, total beta1-integrin expression levels and proliferation were dose-dependently increased by bFGF but not by EGF. EGF rather than bFGF strongly induced the increase of beta1-integrin localization on the NEC surface. bFGF- and EGF-induced beta1-integrin up-regulation and proliferation were inhibited after treatment with a mitogen-activated protein kinase kinase inhibitor, U0126, which indicates the dependence on the mitogen-activated protein kinase pathway. Involvement of beta1-integrin in bFGF- and EGF-induced proliferation was confirmed by the finding that NEC proliferation and adhesion to fibronectin-coated dishes were inhibited by knockdown of beta1-integrin using small interfering RNA. On the other hand, apoptosis was induced in NECs treated with RGD peptide, a small beta1-integrin inhibitor peptide with the Arg-Gly-Asp motif, but it was independent of beta1-integrin expression levels. Those results suggest that regulation of beta1-integrin expression/localization is involved in cellular processes, such as proliferation, induced by bFGF and EGF in NECs. The mechanism underlying the proliferation through beta1-integrin would not be expected to be completely identical, however, for bFGF and EGF.

Src Kinase Activity Is Required for Integrin αVβ3-Mediated Activation of Nuclear Factor-κB

Src Kinase Activity Is Required for Integrin αVβ3-Mediated Activation of Nuclear Factor-κB