• Journal of Korean Neurosurgical Society
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• v.57 no.5
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• pp.329-334
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• 2015

Objective : To comparatively investigate the expression of several integrins in specimens of human bone metastases and degenerative bone tissue. Methods : Degenerative cancellous tissue was obtained from a sample of human degenerative spine. Thirteen human specimens were obtained from metastatic spine tumors, whose primary cancer was colon cancer (n=3), hepatocellular cancer (n=3), lung cancer (n=4), and breast cancer (n=3). The expression of vimentin and integrins ${\alpha}v$, ${\beta}1$, and ${\beta}3$ was assessed in metastatic and degenerative specimens by immunohistochemistry and real-time reverse transcription-polymerase chain reaction (qRT-PCR). Results : Immunohistochemical staining showed that vimentin and integrin ${\alpha}v$ was broadly expressed in all tissues examined. By contrast, integrin ${\beta}1$ was weakly expressed only in 38.4% (5/13) of tissues. Integrin ${\beta}3$ was consistently negative in all cases examined. qRT-PCR analysis showed that vimentin gene expression was higher in all metastatic specimens, as compared to degenerative bone. The gene expression of integrin ${\alpha}v$ in breast specimen was significantly higher than others (p=0.045). The gene expression of integrin ${\beta}1$ was also higher in all metastatic specimens than in degenerative bone tissue. The gene expression of integrin ${\beta}3$ was variable. Conclusion : Spinal metastatic tumors have mesenchymal characteristics such as increased expression of vimentin. The increased expression of integrin ${\alpha}v$ and ${\beta}1$ in spine metastatic tumors suggests that adhesive molecules such as integrin may have implications for the prevention of spine metastasis.

• International Journal of Oral Biology
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• v.32 no.3
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• pp.93-101
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• 2007

Cell behavior of the transformed cells is known to affect by interaction with extracellular matrix (ECM) proteins and integrin. To investigate the alterations of both integrin expression and cell-matrix interaction during neoplastic conversion of human oral kerationcytes, we studied expression levels of integrin subunits by flow cytometry and cellular responses to the ECM proteins in normal human oral keratinocytes (NHOKs), HPV-immortalized HOK-16B line, and three oral cancer cell lines established from HOK-16B line, CTHOK-16B-BaP, CTHOK-16B-DMBA, and CTHOK-16B-Dexa lines. The expression levels of ${\alpha}\;and\;{\beta}$ integrin subunits were shown decreased tendency in human oral keratinocytes undergoing immortalization and tumorigenic transformation except CTHOK-16B-DMBA line tested. Although ${\alpha}v{\beta}6$ integrin is known to be highly expressed in squamous cell carcinomas, and the altered integrin expression is suspected to be associated with cellular carcinogenesis, ${\alpha}v$ integrin subunit and ${\alpha}v{\beta}6$ integrin did not express in oral cancer cell lines tested. Cell behavior to the ECM proteins in HOK-16B line was generally similar to that of exponentially proliferating NHOKs. The adhesion activity profiles of type I collagen were very similar to that of its laminin counterparts, but fibronectin showed minimal adhesion activity under our conditions compared to the BSA control. The ability of the CTHOK-16B-BaP line to spread upon type I collagen and laminin markedly decreased, but migration was notably increased on type I collagen. In contrast, CTHOK-16B-DMBA and CTHOK-16B-Dexa lines spread less but migrated more upon type I collagen than immortalized HOK-16B line. These data indicate that downregulation of integrin subunits causes the changes of cellular responses to the ECM proteins during neoplastic conversion of human oral keratinocytes, and that cellular responses to the ECM proteins in oral cancer cell lines established by exposing different carcinogens are variable according to chemical carcinogens treatment.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.2
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• pp.92-101
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• 2020

The cyclic Arg-Gly-Asp (cRGD) peptide is well-known as a binding molecule to the integrin α_vβ₃ receptor which is highly expressed on activated endothelial cells and new blood vessels in tumors. Although numerous results have been reported by the usage of cRGD peptide-based ligands for cancer diagnosis and therapy, the distinct mechanisms, and functions of cRGD-integrin binding to cancer cells are still being investigated. In this study, we evaluated the internalization efficacy of different types of cRGD peptides (monomer, dimer and tetramer form) in integrin α_vβ₃ overexpressing cancer cells. Western blot and flow cytometric analysis showed U87MG expresses highly integrin α_vβ₃, whereas CT-26 does not show integrin α_vβ₃ expression. Cytotoxicity assay indicated that all cRGD peptides (0-200 µM) had at least 70-80% of viability in U87MG cells. Fluorescence images showed cRGD dimer peptides have the highest cellular internalization compare to cRGD monomer and cRGD tetramer peptides. Additionally, transmission electron microscope results clearly visualized the endocytic internalization of integrin α_vβ₃ receptors and correlated with confocal microscopic results. These results support the rationale for the use of cRGD dimer peptides for imaging, diagnosis, or therapy of integrin α_vβ₃-rich glioblastoma.

• BMB Reports
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• v.51 no.5
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• pp.230-235
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• 2018

Bone resorption by multinucleated osteoclasts is a multistep process involving adhesion to the bone matrix, migration to resorption sites, and formation of sealing zones and ruffled borders. Macrophage colony-stimulating factor (M-CSF) and osteopontin (OPN) have been shown to be involved in the bone resorption process by respective activation of integrin ${\alpha}v{\beta}3$ via "inside-out" and "outside-in" signaling. In this study, we investigated the link between signal modulators known to M-CSF- and OPN-induced osteoclast adhesion and spreading. M-CSF- and OPN-induced osteoclast adhesion was achieved via activation of stepwise signals, including integrin ${\alpha}v{\beta}3$, $PLC{\gamma}$, $PKC{\delta}$, and Rac1. Osteoclast spreading induced by M-CSF and OPN was shown to be controlled via sequential activation, consistent with the osteoclast adhesion processes. In contrast to osteoclast adhesion, osteoclast spreading induced by M-CSF and OPN was blocked via activation of $PLC{\gamma}/PKC{\alpha}/RhoA$ signaling. The combined results indicate that osteoclast adhesion and spreading are selectively regulated via $PLC{\gamma}/PKC{\alpha}-PKC{\delta}/RhoA-Rac1$ signaling.

• Molecules and Cells
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• v.40 no.5
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• pp.355-362
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• 2017

The ${\beta}2$ integrins are cell surface transmembrane proteins regulating leukocyte functions, such as adhesion and migration. Two members of ${\beta}2$ integrin, ${\alpha}M{\beta}2$ and ${\alpha}X{\beta}2$, share the leukocyte distribution profile and integrin ${\alpha}X{\beta}2$ is involved in antigen presentation in dendritic cells and transendothelial migration of monocytes and macrophages to atherosclerotic lesions. ${\underline{R}}eceptor$ for ${\underline{a}}dvanced$ ${\underline{g}}lycation$ ${\underline{e}}nd$ ${\underline{p}}roducts$ (RAGE), a member of cell adhesion molecules, plays an important role in chronic inflammation and atherosclerosis. Although RAGE and ${\alpha}X{\beta}2$ play an important role in inflammatory response and the pathogenesis of atherosclerosis, the nature of their interaction and structure involved in the binding remain poorly defined. In this study, using I-domain as a ligand binding motif of ${\alpha}X{\beta}2$, we characterize the binding nature and the interacting moieties of ${\alpha}X$ I-domain and RAGE. Their binding requires divalent cations ($Mg^{2+}$ and $Mn^{2+}$) and shows an affinity on the sub-micro molar level: the dissociation constant of ${\alpha}X$ I-domains binding to RAGE being $0.49{\mu}M$. Furthermore, the ${\alpha}X$ I-domains recognize the V-domain, but not the C1 and C2-domains of RAGE. The acidic amino acid substitutions on the ligand binding site of ${\alpha}X$ I-domain significantly reduce the I-domain binding activity to soluble RAGE and the alanine substitutions of basic amino acids on the flat surface of the V-domain prevent the V-domain binding to ${\alpha}X$ I-domain. In conclusion, the main mechanism of ${\alpha}X$ I-domain binding to RAGE is a charge interaction, in which the acidic moieties of ${\alpha}X$ I-domains, including E244, and D249, recognize the basic residues on the RAGE V-domain encompassing K39, K43, K44, R104, and K107.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.5
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• pp.225-230
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• 2008

Netrins are secreted molecules and involved in axon guidance, cell migration and tumor development. Recent studies revealed that netrins perform novel functions in such processes as epithelial development and angiogenesis without operating through the classical netrin receptors, DCC (Deleted in Colorectal Cancer) and Unc5h. In the present study, we investigated the roles of netrin-1 and its receptors in cell spreading of human glioblastoma cells, and found that netrin-1 haptotactically enhanced fibronectin-induced cell spreading and focal adhesion formation in U373 glioblastoma cells. Netrin-1 binding to the U373 cell membrane was blocked by an antibody against ${\alpha}v$ integrin subunit, but not by an anti-DCC or anti-Unc5h antibody. In addition, enhancement of the fibronectin response by netrin-1 was abrogated by a function blocking antibody against integrin ${\alpha}v{\beta}3$. Since the ${\alpha}v$ subunit of the integrin family plays an important role in the pathophysiological aspects of cell migration, including tumor angiogenesis and metastasis, our data provide important insight into the molecular mechanism of netrin function.

• Toxicological Research
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• v.29 no.1
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• pp.21-25
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• 2013

The selective targeting of an integrin ${\alpha}_v{\beta}_3$ receptor using radioligands may enable the assessment of angiogenesis and integrin ${\alpha}_v{\beta}_3$ receptor status in tumors. The aim of this research was to label a peptidomimetic integrin ${\alpha}_v{\beta}_3$ antagonist (PIA) with $^{99m}Tc(CO)_3$ and to test its receptor targeting properties in nude mice bearing receptor-positive tumors. PIA was reacted with tris-succinimidyl aminotriacetate (TSAT) (20 mM) as a PIA per TSAT. The product, PIA-aminodiacetic acid (ADA), was radiolabeled with $[^{99m}Tc(CO)_3(H_2O)_3]^{+1}$, and purified sequentially on a Sep-Pak C-18 cartridge followed by a Sep-Pak QMA anion exchange cartridge. Using gradient C-18 reverse-phase HPLC, the radiochemical purity of $^{99m}Tc(CO)_3$-ADA-PIA (retention time, 10.5 min) was confirmed to be > 95%. Biodistribution analysis was performed in nude mice (n = 5 per time point) bearing receptor-positive M21 human melanoma xenografts. The mice were administered $^{99m}Tc(CO)_3$-ADA-PIA intravenously. The animals were euthanized at 0.33, 1, and 2 hr after injection for the biodistribution study. A separate group of mice were also co-injected with 200 ${\mu}g$ of PIA and euthanized at 1 hr to quantify tumor uptake. $^{99m}Tc(CO)_3$-ADA-PIA was stable in phosphate buffer for 21 hr, but at 3 and 6 hr, 7.9 and 11.5% of the radioactivity was lost as histidine, respectively. In tumor bearing mice, $^{99m}Tc(CO)_3$-ADA-PIA accumulated rapidly in a receptor-positive tumor with a peak uptake at 20 min, and rapid clearance from blood occurring primarily through the hepatobiliary system. At 20 min, the tumor-to-blood ratio was 1.8. At 1 hr, the tumor uptake was 0.47% injected dose (ID)/g, but decreased to 0.12% ID/g when co-injected with an excess amount of PIA, indicating that accumulation was receptor mediated. These results demonstrate successful $^{99m}TC$ labeling of a peptidomimetic integrin antagonist that accumulated in a tumor via receptor-specific binding. However, tumor uptake was very low because of low blood concentrations that likely resulted from rapid uptake of the agent into the hepatobiliary system. This study suggests that for $^{99m}Tc(CO)_3$-ADA-PIA to be useful as a tumor detection agent, it will be necessary to improve receptor binding affinity and increase the hydrophilicity of the product to minimize rapid hepatobiliary uptake.

• Advances in nano research
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• v.15 no.2
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• pp.105-111
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• 2023

Integrin αvβ3 is one of the receptors expressed in cancer cells. RGD peptides have the potential to target integrin αvβ3 (receptor), which can increase drug delivery efficiency. In this study, 55 different RGD dimer motifs were investigated. At first, the binding energy between RGD peptides and the receptor was calculated using molecular docking. Then, three RGD peptides with the strongest binding energy with the receptor were selected, and their dynamic adsorption on the receptor was simulated by molecular dynamics (MD). The obtained results showed that a sequence that has RGD at the beginning and end with tryptophan (TRP) has strong Lennard-Jones (LJ) and electrostatic interactions with Integrin αvβ3 and has changed the conformation of receptor significantly, which analyzed by root mean square deviation (RMSD) and radius of gyration.

• 대한생식의학회:학술대회논문집
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• 1996.11a
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• pp.67.2-68
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• 1996

• Biomolecules & Therapeutics
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• v.17 no.2
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• pp.138-143
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• 2009

We have reported previously on a replication incompetent recombinant adenoviral vector, AdLPCD, in which the expression of cytosine deaminase gene (CD) is driven by the tumor-specific L-plastin promoter. AdLPCD vector had been evaluated for its efficacy of chemosensitization of ovarian cancer cells to 5-FC. In spite of the fact that ovarian cancer cells, i.e., OVCAR-3 and SK-OV-3, are capable for adenoviral transduction judged by LacZ reporter gene analysis, two cell lines demonstrated quite different sensitivities toward AdLPCD/5-FC system. In OVCAR-3 cells, infection of AdLPCD followed by exposure to 5-FC resulted in the suppression of cell growth with statistical significance. On the other hand, SK-OV-3 cells were more resistant to the CD/5-FC strategy compared with OVCAR-3 cells under the same condition. The object of study was to investigate factors that would determine the sensitivity to AdLPCD/5-FC. We evaluated conversion rate of 5-FC to 5-FU after infection of AdLPCD by HPLC analysis, $IC_{50}$ of 5-FU, the expression level of integrin receptors i.e., ${\alpha}v{\beta}3$ and ${\alpha}v{\beta}5$, and status of p53 in OVCAR-3 and SK-OV-3 cells. The results indicated that OVCAR-3 cells have few favorable features compared with SK-OV-3 cells to be more effective to the AdLPCD/5-FC strategy; higher level of ${\alpha}v{\beta}5$ integrin, higher rate of conversion of 5-FC into 5-FC, and lower $IC_{50}$ of 5-FU. The results suggest that the replacement of 5-FU with CD/5-FC in combination chemotherapy would be less toxic and much greater cytotoxicity than the conventional combination chemotherapy in some patients.