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1.
Am J Ophthalmol Case Rep ; 33: 101975, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38149093

ABSTRACT

Purpose: In eyes with a prior failed aqueous shunt (or "tube") requiring additional intraocular pressure (IOP) control, options include angle surgery, cyclodestruction, second tube, tube revision, or tube exchange. We present a case of a same-quadrant tube exchange of a Baerveldt-250 (BGI-250) to BGI-350. Observations: The patient is a 71-year-old African American female with severe-stage primary open angle glaucoma of both eyes, and this case focuses on the right eye. This eye had prior cataract surgery with iStent, prior BGI-250 in the anterior chamber (AC), and prior iStent removal with gonioscopy assisted transluminal trabeculotomy (GATT). The visual acuity (VA) was 20/150, and the IOP was 26 mmHg on 3 IOP-lowering medications. The prior superotemporal BGI-250 had its "wings" on top of the superior and lateral rectus muscles and its tube tip in the AC. The implant was removed in its entirety including the superficial and deep layers of its capsule. The new BGI-350 was stented with a 3-0 polypropylene ripcord, ligated with a 7-0 polyglactin suture, and implanted with its wings under the rectus muscles and the tube tip in the sulcus. For early IOP-lowering prior to ligature dissolution, 2 needle stab fenestrations and an additional 7-0 polyglactin wick was used. The capsule from the prior BGI-250 was used as a patch graft for the new BGI-350. The ligature dissolved at postoperative week (POW) 6. By POW8, the IOP was 18 mmHg on 3 IOP-lowering medications and frequent topical steroid, the AC was quiet, and the ripcord was removed. A slow steroid taper finished at postoperative month (POM) 6. By POM 12, the VA was still at baseline 20/150, and the IOP was 14 mmHg on 3 IOP-lowering medications. Conclusions & importance: Patients with a prior failed tube requiring additional IOP-lowering can undergo a same-quadrant tube exchange. BGI-350s may offer more IOP-lowering than BGI-250s, but the IOP-lowering achieved in this patient's case could be attributable to differences in postoperative management in addition to endplate size; longer follow-up is needed. A tube exchange offers the opportunity to reposition the tube tip from the AC to the sulcus and to use the prior tube's capsule as a patch graft for the new tube.

3.
Biochem Biophys Res Commun ; 457(1): 65-70, 2015 Jan 30.
Article in English | MEDLINE | ID: mdl-25534855

ABSTRACT

ß-Catenin is the key transcriptional activator of canonical Wnt signaling in the nucleus; thus, nuclear accumulation of ß-catenin is a critical step for expressing target genes. ß-Catenin accumulates in the nucleus of cancer cells where it activates oncogenic target genes. Hu antigen R (HuR) is a RNA binding protein that regulates multiple post-transcriptional processes including RNA stability. Thus, cytoplasmic HuR protein may be involved in tumorigenesis by stabilizing oncogenic transcripts, but the molecular mechanism remains unclear. Here, we observed that Wnt/ß-catenin signaling induced export of the HuR protein, whereas HuR overexpression promoted accumulation of the ß-catenin protein in the cytoplasm. Thus, Wnt/ß-catenin-mediated transcriptional activity in the nucleus was reduced by overexpressing HuR. These results suggest novel and uncharacterized cytoplasmic ß-catenin functions related to HuR-mediated RNA metabolism in cancer cells.


Subject(s)
Cytoplasm/metabolism , ELAV Proteins/metabolism , Transcriptional Activation , Wnt Signaling Pathway , beta Catenin/metabolism , Cell Line , Cytoplasm/drug effects , ELAV-Like Protein 1 , Humans , Lithium Chloride/pharmacology , Models, Biological , Protein Stability/drug effects , Protein Transport/drug effects , TCF Transcription Factors/metabolism , Transcription, Genetic/drug effects , Transcriptional Activation/drug effects , Wnt Signaling Pathway/drug effects
4.
Environ Sci Technol ; 46(20): 11021-7, 2012 Oct 16.
Article in English | MEDLINE | ID: mdl-22963502

ABSTRACT

Membrane fouling remains a critical factor limiting the widespread use of membrane processes in water and wastewater treatment. To mitigate membrane fouling, we introduced a patterned morphology on the membrane surface using a lithographic method. A modified immersion precipitation method was developed to relieve the formation of dense layer at the solvent-nonsolvent interface, that is, the opposite side of the patterned surface. Diverse patterned membranes, such as pyramid-, prism-, and embossing-patterned membranes, were prepared and compared with a flat membrane in terms of morphology, permeability, and biofouling. Patterned membrane fidelity was largely dependent on the polymer concentration in cast solution. The patterned surface augmented the water flux in proportion to the roughness factor of the patterned membrane. However, the type of pattern did not affect substantially the mean pore size on the patterned surface. Deposition of microbial cells on the patterned membrane was significantly reduced compared to that on the flat membrane in the membrane bioreactor (MBR) for wastewater treatment. This was attributed to hydraulic resistance of the apex of the patterned surface, which induced local turbulence.


Subject(s)
Filtration/instrumentation , Membranes, Artificial , Waste Disposal, Fluid/methods , Water Purification/methods , Biofouling , Bioreactors , Permeability , Polymers/chemistry , Water Pollutants, Chemical/analysis
5.
Nucleic Acids Res ; 40(14): 6863-72, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22544606

ABSTRACT

RNA-binding proteins regulate multiple steps of RNA metabolism through both dynamic and combined binding. In addition to its crucial roles in cell adhesion and Wnt-activated transcription in cancer cells, ß-catenin regulates RNA alternative splicing and stability possibly by binding to target RNA in cells. An RNA aptamer was selected for specific binding to ß-catenin to address RNA recognition by ß-catenin more specifically. Here, we characterized the structural properties of the RNA aptamer as a model and identified a ß-catenin RNA motif. Similar RNA motif was found in cellular RNA, Cyclooxygenase-2 (COX-2) mRNA 3'-untranslated region (3'-UTR). More significantly, the C-terminal domain of ß-catenin interacted with HuR and the Armadillo repeat domain associated with RNA to form the RNA-ß-catenin-HuR complex in vitro and in cells. Furthermore, the tertiary RNA-protein complex was predominantly found in the cytoplasm of colon cancer cells; thus, it might be related to COX-2 protein level and cancer progression. Taken together, the ß-catenin RNA aptamer was valuable for deducing the cellular RNA aptamer and identifying novel and oncogenic RNA-protein networks in colon cancer cells.


Subject(s)
3' Untranslated Regions , Colonic Neoplasms/metabolism , Cyclooxygenase 2/genetics , ELAV Proteins/metabolism , RNA-Binding Proteins/metabolism , beta Catenin/metabolism , Aptamers, Nucleotide/chemistry , Binding Sites , Cell Line, Tumor , Colonic Neoplasms/genetics , HEK293 Cells , Humans , Nucleotide Motifs , Protein Interaction Domains and Motifs , RNA, Messenger/chemistry , RNA-Binding Proteins/chemistry , beta Catenin/chemistry
6.
Lasers Med Sci ; 27(2): 459-67, 2012 Mar.
Article in English | MEDLINE | ID: mdl-21814735

ABSTRACT

Human gingival fibroblasts (hGFs) play an important role in the inflammatory reaction to lipopolysaccharide (LPS) from P. gingivalis, which infects periodontal connective tissue. In addition, although light-emitting diode (LED) irradiation has been reported to have biostimulatory effects, including anti-inflammatory activity, the pathological mechanisms of these effects are unclear. This study examined the effects of 635-nm irradiation of P. gingivalis LPS-treated human gingival fibroblasts on inflammatory cytokine profiles and the mitogen-activated protein kinase (MAPK) pathway, which is involved in cytokine production. Gingival fibroblasts treated or not treated with P. gingivalis LPS were irradiated with 635-nm LED light, and cytokine profiles in the supernatant were assessed using a human inflammation antibody array. Expression of cyclooxyginase-2 (COX-2) protein and phosphorylation of extracellular signal-regulated kinase (ERK 1/2), p38, and c-Jun-N-terminal kinase (JNK) were assessed by Western-blot analysis to determine the effects on the MAPK pathway, and prostaglandin E(2) (PGE(2)) in the supernatant was measured using an enzyme-linked immunoassay. COX-2 protein expression and PGE(2) production were significantly increased in the LPS-treated group and decreased by LED irradiation. LPS treatment of gingival fibroblasts led to the increased release of the pro-inflammatory-related cytokines interleukin-6 (IL-6) and IL-8, whereas LED irradiation inhibited their release. Analysis of MAPK signal transduction revealed a considerable decrease in p38 phosphorylation in response to 635-nm radiation either in the presence or absence of LPS. In addition, 635-nm LED irradiation significantly promoted JNK phosphorylation in the presence of LPS. LED irradiation can inhibit activation of pro-inflammatory cytokines, mediate the MAPK signaling pathway, and may be clinically useful as an anti-inflammatory tool.


Subject(s)
Cytokines/metabolism , Fibroblasts/immunology , Gingiva/immunology , Lasers, Semiconductor/therapeutic use , Periodontal Diseases/immunology , Porphyromonas gingivalis/radiation effects , Blotting, Western , Cell Culture Techniques , Cyclooxygenase 2/metabolism , Dinoprostone/metabolism , Enzyme-Linked Immunosorbent Assay , Fibroblasts/metabolism , Gingiva/cytology , Gingiva/radiation effects , Humans , Lipopolysaccharides/pharmacology , MAP Kinase Signaling System/immunology , Mitogen-Activated Protein Kinase 3/immunology , Periodontal Diseases/metabolism , Signal Transduction
7.
Pharm Biol ; 48(12): 1354-60, 2010 Dec.
Article in English | MEDLINE | ID: mdl-20738175

ABSTRACT

CONTEXT: A growing body of evidence shows that compounds of plant origin have the ability to prevent cancer. The fruit of gardenia, Gardenia jasminoides Ellis (Rubiaceae), has long been used as a food additive and herbal medicine, and its pharmacological actions, such as protective activity against oxidative damage, cytotoxic effect, and anti-inflammatory and anti-tumor activity, have already been reported. OBJECTIVE: The purpose of the present study was to investigate the presence of DNA topoisomerase 1 inhibitor in various solvent fractions of Gardenia extract and examine the induction of oral cancer cell death upon treatment with Gardenia extract. MATERIALS AND METHODS: The methanol extract of Gardenia was partitioned with n-hexane, dichloromethane, ethyl acetate, n-butanol, and water. RESULTS: In the DNA topoisomerase 1 assay, n-hexane and dichloromethane fractions inhibited topoisomerase 1 and led to a decrease in the cell viability of KB cells. The dichloromethane fraction (0.1 mg/mL) also showed 77% inhibition of cell viability in KB cells compared with HaCaT cells. Treatment with dichloromethane fraction led to apoptotic cell death as evidenced by flow cytometric analysis and morphological changes. In addition, treatment with Gardenia extract dichloromethane fraction led to the partial increase of caspase-3, caspase-8 and caspase-9 activities and the cleavage of poly (ADP-ribose) polymerase. CONCLUSION: Taken together, these results suggest that the dichloromethane fraction from Gardenia extract induces apoptotic cell death by DNA topoisomerase 1 inhibition in KB cells. These findings suggest the possibility that Gardenia extract could be developed as an anticancer modality.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Gardenia/chemistry , Mouth Neoplasms/drug therapy , Plant Extracts/pharmacology , Antineoplastic Agents, Phytogenic/isolation & purification , Apoptosis/drug effects , Caspases/drug effects , Caspases/metabolism , Cell Line , Cell Line, Tumor , Cell Survival/drug effects , DNA Topoisomerases, Type I/drug effects , Flow Cytometry , Fruit , Humans , KB Cells , Methylene Chloride/chemistry , Mouth Neoplasms/pathology , Poly(ADP-ribose) Polymerases/drug effects , Poly(ADP-ribose) Polymerases/metabolism , Solvents/chemistry
8.
Article in English | MEDLINE | ID: mdl-20451836

ABSTRACT

An oncocytic mucoepidermoid carcinoma arising from the minor salivary gland origin is extremely rare. We report on a 44-year-old man with a high-grade oncocytic mucoepidermoid carcinoma originating in the minor salivary gland of the posterior mandible. All tumor cells showed the expected pattern of immunoreactivity, with positive results for the antimitochondrial antibody and p63, and negative results for the androgenic receptor antibody. Microscopically, the tumor was considered to be a high-grade carcinoma in the grading systems of the Armed Forces Institute of Pathology and Brandwein. The patient underwent a partial mandibulectomy, and the lesion was reconstructed with a right fibula osteofasciocutaneous flap under general anesthesia. The patient is currently under long-term follow-up.


Subject(s)
Mucoepidermoid Tumor/pathology , Salivary Gland Neoplasms/pathology , Salivary Glands, Minor/pathology , Adult , Autoantibodies/metabolism , Humans , Immunophenotyping , Male , Membrane Proteins/immunology , Mitochondria/immunology , Mucoepidermoid Tumor/immunology , Mucoepidermoid Tumor/metabolism , Mucoepidermoid Tumor/surgery , Oxyphil Cells/pathology , Salivary Gland Neoplasms/immunology , Salivary Gland Neoplasms/metabolism , Salivary Gland Neoplasms/surgery , Salivary Glands, Minor/immunology , Salivary Glands, Minor/metabolism , Salivary Glands, Minor/surgery , Treatment Outcome
9.
J Biomed Mater Res B Appl Biomater ; 93(1): 113-21, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20119940

ABSTRACT

Poor interaction between cells and surfaces, especially hydrophobic surfaces, results in delayed proliferation and increased apoptosis due to low cell adhesion signaling. To improve cell adhesion, hydrophilic array of amorphous calcium phosphate (ACP) was fabricated on a surface. A phosphate-buffered solution containing calcium ions was prepared at low temperature to prevent spontaneous precipitation. Then, the ion solution was heated to generate nuclei of ACP nanoparticles. The ACP nanoparticles adhered to the hydrophobic polystyrene surface forming an array composed of ACP particles. Multiple treatments of these nuclei with fresh CaP ion solutions increased the diameter and decreased the solubility of ACP particles enough to mediate cellular adhesion. The particle density in the array was dependent on the ion concentration of the CaP ion solutions. The ACP array improved a wide variety of activities when osteoblastic MC3T3-E1 cells were cultured on the ACP array fabricated on a hydrophobic bacteriological dish surface, compared to those cultured without the ACP array in vitro. The use of ACP array resulted in a lower apoptosis and also increased the spreading of cells to form stress fibers and focal contacts. Cells cultured on the ACP array proliferated more than cells cultured on a hydrophobic surface without the ACP array. The ACP array increased the expression of markers of differentiation in osteoblast. These results indicate that an array of ACP can be used as a coating material for enhancing biocompatibility in tissue engineering or biomaterials rather than modifying the surface with organic molecules.


Subject(s)
Calcium Phosphates/chemistry , Coated Materials, Biocompatible/chemistry , 3T3 Cells , Alkaline Phosphatase/metabolism , Animals , Apoptosis , Base Sequence , Cell Cycle , Cell Proliferation , DNA Primers/genetics , Gene Expression , Genes, Reporter , Hydrophobic and Hydrophilic Interactions , Luciferases/genetics , Materials Testing , Mice , Nanoparticles/chemistry , Osteoblasts/cytology , Osteoblasts/metabolism , Particle Size , Surface Properties , Tissue Engineering
10.
Free Radic Biol Med ; 47(6): 850-7, 2009 Sep 15.
Article in English | MEDLINE | ID: mdl-19545621

ABSTRACT

Nitric oxide (NO) is a major factor contributing to the loss of neurons in ischemic stroke, demyelinating diseases, and other neurodegenerative disorders. NO not only functions as a direct neurotoxin, but also combines with superoxide (O(2)(-)) by a diffusion-controlled reaction to form peroxynitrite (ONOO(-)), a species that contributes to oxidative signaling and cellular apoptosis. However, the mechanism by which ONOO(-) induces apoptosis remains unclear, although subsequent formation of reactive oxygen species (ROS) has been suggested. The aim of this study was to further investigate the triggers of the apoptotic pathway using O(2)(-) scavenging with light irradiation to block ONOO(-) production. Antiapoptotic effects of light irradiation in sodium nitroprusside (SNP)-treated SH-SY5Y cells were assayed by reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, DNA fragmentation, flow cytometry, Western blot, and caspase activity assays. In addition, NO, total ROS, O(2)(-), and ONOO(-) levels were measured to observe changes in NO and its possible involvement in radical induction. Cell survival was reduced to approximately 40% of control levels by SNP treatment, and this reduction was increased to 60% by low-level light irradiation. Apoptotic cells were observed in the SNP-treated group, but the frequency of these was reduced in the irradiation group. NO, O(2)(-), total ROS, and ONOO(-) levels were increased after SNP treatment, but O(2)(-), total ROS, and ONOO(-) levels were decreased after irradiation, despite the high NO concentration induced by SNP treatment. Cytochrome c was released from mitochondria of SNP-treated SH-SY5Y cells, but not of irradiated cells, resulting in a decrease in caspase-3 and -9 activity in SNP-treated cells. Finally, these results show that 635-nm irradiation, by promoting the scavenging of O(2)(-), protected against neuronal death through blocking the mitochondrial apoptotic pathway induced by ONOO(-) synthesis.


Subject(s)
Apoptosis/radiation effects , Mitochondria/physiology , Neurons/metabolism , Neurons/radiation effects , Nitric Oxide/metabolism , Nitroprusside/metabolism , Apoptosis/physiology , Caspase 3/metabolism , Caspase 9/metabolism , Cell Line, Tumor , Cytochromes c/metabolism , DNA Fragmentation/radiation effects , Humans , Light , Mitochondria/radiation effects , Neurons/pathology , Peroxynitrous Acid/metabolism , Superoxides/metabolism , Tetrazolium Salts/metabolism , Thiazoles/metabolism
11.
Photomed Laser Surg ; 27(3): 453-60, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19416004

ABSTRACT

OBJECTIVE: The objective of this study is to investigate the effect of intracellular photosensitizer distribution on tumor cell death after photodynamic therapy (PDT). BACKGROUND DATA: The photosensitizer accumulates in tumor tissue during PDT, and generates intracellular reactive oxygen species (ROS), resulting in tumor cell death. MATERIALS AND METHODS: This study was carried out to elucidate the effects of PDT in a KB oral cancer cell line using hematoporphyrin with irradiation at 635 nm and 5 mW/cm(2). After irradiation, the MTT reduction method, agarose gel electrophoresis, flow cytometry, and Diff-Quick staining were performed. The intracellular ROS level was measured by DCF-DA. Intracellular hematoporphyrin was monitored with a confocal microscope, and Western blot and caspase activity assays were performed. RESULTS: In our study, cell survival was reduced by about 50% after 3 h of hematoporphyrin incubation time. In DNA fragmentation, flow cytometry, and Diff-Quick assay, necrosis was identified within 12 h and apoptosis soon thereafter. Confocal microscopy revealed that hematoporphyrin was localized in the cell membrane, cytoplasm, and nucleus as time passed. The quantities of intracellular ROS correlated with the time of hematoporphyrin accumulation. Additionally, Western blot analysis of Bcl-2/Bax, the release of cytochrome C, and activity of caspase-3 and caspase-9 showed that apoptosis followed the mitochondria-dependent pathway. CONCLUSION: PDT with hematoporphyrin in the KB cell line showed morphological changes of cell necrosis and apoptosis, which were associated with the time of distribution and localization of hematoporphyrin. Also, the apoptosis evoked followed the mitochondria-dependent pathway.


Subject(s)
Hematoporphyrin Photoradiation , Hematoporphyrins/pharmacology , Mouth Neoplasms/pathology , Photosensitizing Agents/pharmacology , Apoptosis , Blotting, Western , Cell Death , Cell Line, Tumor , Cell Survival , DNA Fragmentation , Electrophoresis, Agar Gel , Flow Cytometry , Hematoporphyrins/pharmacokinetics , Humans , KB Cells , Microscopy, Confocal , Photosensitizing Agents/pharmacokinetics , Reactive Oxygen Species/metabolism , Staining and Labeling
12.
Photomed Laser Surg ; 26(3): 215-20, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18484909

ABSTRACT

OBJECTIVE: The purpose of this study was to examine the protection afforded by 635-nm irradiation against ultraviolet (UV)-C-induced apoptosis in primary human gingival fibroblasts (hGFs). BACKGROUND DATA: UV irradiation is known to cause photoaging and cellular apoptosis of skin cells and is considered to be one of the leading causes of skin carcinogenesis. MATERIALS AND METHODS: To induce apoptosis, UV-C (100 mJ/cm2) was used to irradiate hGFs. To protect them from apoptosis, pretreatment with 635-nm irradiation was performed for 1 h immediately after cell plating 36 or 48 h before UV-C irradiation. The light source used for irradiation was a continuous-wave 635-nm LED laser emitting at 1 mW/cm2. Experimental samples were selected 24 h after UV-C irradiation. To measure the numbers of apoptotic cells, MTT assay and flow cytometric analyses were performed. For histomorphologic findings, Diff-Quick staining was carried out. Also, the activities and mRNA expression of caspase-3, caspase-8, and caspase-9 were measured. RESULTS: In the present study, the number of apoptotic cells declined in the cells that were pretreated with 635-nm light irradiation in a time-dependent manner. In addition, the activities and mRNA expression of caspase-3, caspase-8, and caspase-9 were significantly recovered by pretreatment with 635-nm irradiation. CONCLUSION: These results suggest that 635-nm visible light irradiation may be used as a protective tool to prevent UV-C-induced apoptosis.


Subject(s)
Apoptosis/radiation effects , Fibroblasts/radiation effects , Gingiva/cytology , Lasers , Ultraviolet Rays , Caspase 3/analysis , Caspase 8/analysis , Caspase 9/analysis , Cells, Cultured , Fibroblasts/cytology , Fibroblasts/enzymology , Gingiva/radiation effects , Humans
13.
Lasers Surg Med ; 39(7): 614-21, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17868110

ABSTRACT

BACKGROUND AND OBJECTIVES: Inhibition of cyclooxygenase (COX) and prostaglandin E(2) (PGE(2)) protects cells against cell injury in specific pathophysiological situations: inflammation and oxidative stress. Although the anti-inflammatory effects have been reported in clinical fields for specific wavelength irradiation during wound healing, the physiological mechanism has not been clarified yet. The aim of the present study is to investigate the anti-inflammatory mechanism of 635 nm light-emitting-diode (LED) irradiation compared with existing COX inhibitors. STUDY DESIGN/MATERIALS AND METHODS: The present study investigated anti-inflammatory effects of 635 nm irradiation on PGE(2) release, COX and phospholipase A(2) (PLA(2)) expression, and reactive oxygen species (ROS) dissociation in arachidonic acid (AA)-treated human gingival fibroblast (hGF). These results were compared with their existing COX inhibitors: indomethacin and ibuprofen. The PGE(2) release was measured by enzyme immunoassay, the COX expression was measured by western blot and reverse transcriptase polymerase chain reaction (RT-PCR), and ROS level was measured by flow cytometry, laser scanning confocal microscope and RT-PCR. RESULTS: Results showed that 635 nm irradiation and existing COX inhibitors inhibit expression of COX and PGE(2) release. Unlike indomethacin and ibuprofen, 635 nm irradiation leads to a decrease of ROS levels and mRNA expression of cytosolic phospholipase A(2) (cPLA(2)) and secretary phospholipase A(2) (sPLA(2)). CONCLUSION: Taken together, 635 nm irradiation, unlike indomethacin and ibuprofen, can directly dissociate the ROS. This inhibits cPLA(2), sPLA(2), and COX expression, and results in the inhibition of PGE(2) release. Thus, we suggest that 635 nm irradiation inhibits PGE(2) synthesis like COX inhibitor and appears to be useful as an anti-inflammatory tool.


Subject(s)
Cyclooxygenase Inhibitors/therapeutic use , Gingival Diseases/drug therapy , Gingival Diseases/radiotherapy , Phototherapy/methods , Adult , Biomarkers , Blotting, Western , Dinoprostone/biosynthesis , Dinoprostone/genetics , Fibroblasts/drug effects , Fibroblasts/metabolism , Fibroblasts/radiation effects , Flow Cytometry , Gingival Diseases/pathology , Humans , Ibuprofen/therapeutic use , Indomethacin/therapeutic use , Microscopy, Confocal , Oxidative Stress/drug effects , Oxidative Stress/genetics , Oxidative Stress/radiation effects , Prostaglandin-Endoperoxide Synthases/biosynthesis , Prostaglandin-Endoperoxide Synthases/genetics , RNA/genetics , Reactive Oxygen Species/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Wound Healing/drug effects , Wound Healing/radiation effects
14.
Exp Cell Res ; 303(1): 197-206, 2005 Feb 01.
Article in English | MEDLINE | ID: mdl-15572039

ABSTRACT

The hydrophobic (HPB) nature of most polymeric biomaterials has been a major obstacle in using those materials in vivo due to low compatibility with cells. However, there is little knowledge of the molecular detail to explain how surface hydrophobicity affects cell responses. In this study, we compared the proliferation and apoptosis of human osteoblastic MG63 cells adhered to hydrophilic (HPL) and hydrophobic surfaces. On the hydrophobic surface, less formation of focal contacts and actin stress fibers, a delay in cell cycle progression, and an increase in apoptosis were observed. By using fibroblast growth factor 1 (FGF1) as a model growth factor, we also investigated intracellular signaling pathways on hydrophilic and hydrophobic surfaces. The activation of Ras, Akt, and ERK by FGF1 was impaired in MG63 cells on the hydrophobic surface. The overexpression of constitutively active form of Ras and Akt rescued those cells from apoptosis and recovered cell cycle progression. Furthermore, their overexpression also restored the actin cytoskeletal organization on the hydrophobic surface. Finally, the proliferative, antiapoptotic, and cytoskeletal effects of constitutively active Ras in MG63 cells on the hydrophobic surface were blocked by wortmannin and PD98059 that inhibit Akt and ERK activation, respectively. Therefore, our results suggest that the activation of Ras and its downstream molecules Akt and ERK to an appropriate level is one of crucial elements in the determination of osteoblast cell responses. The Ras pathway may represent a cell biological target that should be considered for successful surface modification of biomaterials to induce adequate cell responses in the bone tissue.


Subject(s)
Apoptosis/physiology , Cell Proliferation , Focal Adhesions/metabolism , Osteoblasts/metabolism , Signal Transduction/physiology , Androstadienes/pharmacology , Cell Adhesion/physiology , Cells, Cultured , Extracellular Signal-Regulated MAP Kinases/antagonists & inhibitors , Extracellular Signal-Regulated MAP Kinases/metabolism , Fibroblast Growth Factor 1/pharmacology , Flavonoids/pharmacology , Genes, ras/physiology , Humans , Hydrophobic and Hydrophilic Interactions , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/metabolism , Proto-Oncogene Proteins/antagonists & inhibitors , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins c-akt , Stress Fibers/metabolism , Wortmannin
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