ABSTRACT
Protein assemblies have drawn much attention as platforms for biomedical applications, including gene/drug delivery and vaccine, due to biocompatibility and functional diversity. Here, the construction and functionalization of a protein assembly composed of human clathrin heavy chain and light chain for a targeted protein delivery, is presented. The clathrin heavy and light chains are redesigned and associated with each other, and the resulting triskelion unit further self-assembled into a clathrin assembly with the size of about 28 nm in diameter. The clathrin assembly is dual-functionalized with a protein cargo and a targeting moiety using two different orthogonal protein-ligand pairs through one-pot reaction. The functionalized clathrin assembly exhibits about a 900-fold decreased KD value for a cell-surface target due to avidity compared to a native targeting moiety. The utility of the clathrin assembly is demonstrated by an efficient delivery of a protein cargo into tumor cells in a target-specific manner, resulting in a strong cytotoxic effect. The present approach can be used in the creation of protein assemblies with multimodality.
Subject(s)
Clathrin , Drug Delivery Systems , Humans , Clathrin/metabolismABSTRACT
Pt-supported on ZIF-8 derived porous carbon (CZIF8) and nitrogen-doped multi-walled carbon nanotubes (NCNT) composites was prepared by pyrolysis process and chemical reduction. The electrochemical characterization and morphological analysis of composites was measured by cyclic voltammetry (CV), chronoamperometry, transmission electron microscope (TEM), and fourier transform infrared spectroscopy (FT-IR). These results indicate that the Pt-NCNT@CZIF8 nanocomposite showed electrochemically superior properties to methanol oxidation reaction and the higher electrochemical surface area (ECSA). Also, ZIF-8 derived carbon and modified the CNTs was thought to enhance the effective area of the platinum deposition site.
ABSTRACT
A stimuli-responsive protein self-assembly offers promising utility as a protein nanocage for biotechnological and medical applications. Herein, the development of a virus-like particle (VLP) that undergoes a transition between assembly and disassembly under a neutral and acidic pH, respectively, for a targeted delivery is reported. The structure of the bacteriophage P22 coat protein is used for the computational design of coat subunits that self-assemble into a pH-responsive VLP. Subunit designs are generated through iterative computational cycles of histidine substitutions and evaluation of the interaction energies among the subunits under an acidic and neutral pH. The top subunit designs are tested and one that is assembled into a VLP showing the highest pH-dependent structural transition is selected. The cryo-EM structure of the VLP is determined, and the structural basis of a pH-triggered disassembly is delineated. The utility of the designed VLP is exemplified through the targeted delivery of a cytotoxic protein cargo into tumor cells in a pH-dependent manner. These results provide strategies for the development of self-assembling protein architectures with new functionality for diverse applications.
Subject(s)
Bacteriophage P22 , Capsid Proteins , Capsid Proteins/metabolism , Bacteriophage P22/chemistry , Bacteriophage P22/metabolism , Hydrogen-Ion ConcentrationABSTRACT
Esophageal stethoscope is less invasive and easy to handling. And it gives a lot of information. The purpose of this study is to investigate the correlation of blood pressure and heart sound as measured by esophageal stethoscope. Four male beagles weighing 10 to 12 kg were selected as experimental subjects. After general anesthesia, the esophageal stethoscope was inserted. After connecting the microphone, the heart sounds were visualized and recorded through a self-developed equipment and program. The amplitudes of S1 and S2 were monitored real-time to examine changes as the blood pressure increased and decreased. The relationship between the ratios of S1 to S2 (S1/S2) and changes in blood pressure due to ephedrine was evaluated. The same experiment was performed with different concentration of isoflurane. From S1 and S2 in the inotropics experiment, a high correlation appeared with change in blood pressure in S1. The relationship between S1/S2 and change in blood pressure showed a positive correlation in each experimental subject. In the volatile anesthetics experiment, the heart sounds decreased as MAC increased. Heart sounds were analyzed successfully with the esophageal stethoscope through the self-developed program and equipment. A proportional change in heart sounds was confirmed when blood pressure was changed using inotropics or volatile anesthetics. The esophageal stethoscope can achieve the closest proximity to the heart to hear sounds in a non-invasive manner.
Subject(s)
Diagnosis, Computer-Assisted/instrumentation , Esophagus/physiology , Heart Auscultation/instrumentation , Heart Sounds/physiology , Signal Processing, Computer-Assisted/instrumentation , Sound Spectrography/instrumentation , Stethoscopes , Animals , Blood Pressure/physiology , Dogs , Equipment Design , Equipment Failure Analysis , Heart Auscultation/methods , Male , Reproducibility of Results , Sensitivity and Specificity , Sound Spectrography/methodsABSTRACT
Research on low-cost bio-adsorbents for the removal of harmful substances from effluents has recently attracted significant attention. In this study, three types of amino-silane-modified lignins (ASLs) with primary, secondary, and tertiary amine groups were prepared, and their adsorption behavior toward cationic and anionic dyes was investigated. Chemical structural analyses indicated that the three amino-silane reagents resulted in different molecular self-assembly structures on the lignin surface. The ASLs exhibited enhanced thermal stabilities and increased surface areas with different surface charges in different pH ranges. Owing to the high density of primary, secondary, and tertiary amine groups, the ASLs exhibited excellent adsorption capacities for cationic and anionic dyes. Additionally, they selectively adsorb anionic and cationic dyes according to the pH conditions. The ASL with primary amine had the highest adsorption capacity for Methylene blue and Congo red, reaching 187.27 and 293.26 mg·g-1, respectively, followed by ASLs with the secondary amine and tertiary amine. All adsorption processes followed the Langmuir and Temkin isotherms and had pseudo-second-order kinetics. The hypothesized adsorption mechanism mainly involves electrostatic interaction, NH-π interaction, hydrogen bonding interaction and π-π interaction.
Subject(s)
Congo Red , Water Pollutants, Chemical , Adsorption , Amines , Coloring Agents , Hydrogen-Ion Concentration , Kinetics , Lignin/chemistry , Methylene Blue/analysis , Water Pollutants, Chemical/analysisABSTRACT
Muscle relaxants may exacerbate the symptoms of amyotrophic lateral sclerosis (ALS). Furthermore, ALS patients often experience respiratory muscle weakness. Herein, we report the case of a 63-year-old man with ALS who underwent pulmonary wedge resection using total intravenous anesthesia without muscle relaxant and single lumen endotracheal tube. After an unremarkable surgical procedure, the patient was transferred to the intensive care unit after extubation. The patient did not experience any worsening of ALS symptoms over the one-year follow-up period. Our experience shows that total intravenous anesthesia without muscle relaxants can be used as an anesthetic method for lung surgery in ALS patients. We report this case along with a brief literature review.
ABSTRACT
Multifunctional polymers derived from renewable organic substances have received significant attention. In this work, the Diels-Alder "click" reaction was used to synthesize a renewable copolymer with the mechanical strength of cellulose nanocrystals (CNCs) and the natural antioxidant activity of lignin. Chemical structural analysis and molecular weight results confirmed that lignin was successfully attached to the CNCs. Phenolic hydroxyl groups were introduced into CNCs, resulting in good antioxidant activity with an IC50 value of 1.49 mg/mL, although a slight decrease in the crystallinity index and thermal properties was observed. Additionally, carboxymethyl cellulose (CMC) films containing lignin-modified CNCs were prepared by solution casting. The lignin-modified CNCs endowed film with antioxidant activity and also contributed to increasing the tensile strength by 70%. This indicated that the lignin-modified CNCs with good antioxidant activities and mechanical strength have promising applications in multifunctional materials.
ABSTRACT
The assembly of proteins in a programmable manner provides insight into the creation of novel functional nanomaterials for practical applications. Despite many advances, however, a rational protein assembly with an easy scalability in terms of size and valency remains a challenge. Here, a simple bottom-up approach to the supramolecular protein assembly with a tunable size and valency in a programmable manner is presented. The dendrimer-like protein assembly, simply called a "protein dendrimer," is constructed through a stepwise and alternate addition of a building block protein. Starting from zeroth-generation protein dendrimer (pG0 ) of 27 kDa, the protein dendrimer is sequentially grown to pG1 , pG2 , pG3 , to pG4 with a molecular mass of 94, 216, 483, and 959 kDa, respectively. The valency of the protein dendrimers at the periphery increases by a factor of two after each generation, allowing a tunable valency and easy functionalization. The protein dendrimers functionalizes with a targeting moiety and a cytotoxic protein cargo shows a typical feature of multi-valency in the avidity and a highly enhanced cellular cytotoxicity, exemplifying their utility as a protein delivery platform. The present approach can be effectively used in the creation of protein architectures with new functions for biotechnological and medical applications.
Subject(s)
Antineoplastic Agents/administration & dosage , Dendrimers/metabolism , Neoplasms/drug therapy , Cell Line, Tumor , Cells, Cultured , Humans , Microscopy, Confocal , Nanostructures , Neoplasms/diagnostic imagingABSTRACT
Cellulose from different lignocellulosic biomass can be used to prepare various materials. In this work, the cellulose nanofibrils were produced from hardwood bleached kraft pulp. Then, a novel biosorbent from cellulose nanofibrils grafted with poly(m-aminobenzene sulfonate) (PABS) was prepared for effective detoxification and adsorption of Cr(VI) in an aqueous medium. 6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCNF) with a high aspect ratio was used as an adsorbent matrix. PABS, an amine-rich conductive polymer, was grafted onto TOCNF via a successive two-step reaction. The analyses of Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) confirmed the successful grafting reaction between TOCNF and PABS. The biosorbent from TOCNF-bonded PABS with the nitrogen content of 7.0% was synthesized. It exhibited excellent Cr(VI) adsorption capacity at a solution pH below 3, and almost 100% Cr(VI) can be removed. The adsorption of Cr(VI) on the biosorbent was described by a pseudo-second-order model and obeyed the Langmuir model. The Cr(VI) adsorption capacity of the biosorbent from TOCNF-bonded PABS was almost 10 times higher than that of TOCNF. It was interesting to note that part of Cr(VI) ions had been reduced to Cr(III) during the adsorption process. It indicated that the biosorbent from TOCNF grafted with PABS could detoxify and adsorb Cr(VI) synchronously.
ABSTRACT
Cutaneous melanoma is known to be one of the most dangerous skin cancers because of its metastatic functions. Today, it is essential to investigate specific biomarkers for the target treatment in many diseases including cancers. DJ-1 protein, also known as Parkinson disease 7, has various functions associated with cancer progression including cell survival and migration. Phosphatase and tensin homolog (PTEN) is a tumor suppressor that regulates the PI3K/AKT signaling pathway and its mutations have been reported to frequently occur in many cancers such as thyroid, breast and skin. Recently, DJ-1 has been identified as a negative regulator of PTEN in many human cancer cells. However, the impacts and relationship of DJ-1 and PTEN have not been studied yet in melanoma. To confirm the expression of DJ-1 and PTEN in melanoma compared to normal skin tissues and find out functions of DJ-1 in melanoma cells, Western blot analysis and immunohistochemical staining were used. Transfection of G361 cells with DJ-1-specific small interfering RNA was performed to figure out the roles of DJ-1 and the relationship between DJ-1 and PTEN in melanoma cells. In our study, the DJ-1 protein was significantly increased with loss of PTEN protein in melanoma compared to that in normal skin. Inhibition of DJ-1 in G361 cells induced apoptosis, and suppressed cell survival and migration. Furthermore, suppression of DJ-1 in G361 cells increased the expression of cleaved caspase-3, cleaved PARP, Bax, p53, and Daxx as well as PTEN, while it decreased expression of survivin, caspase-3, and PARP. Also, downregulated DJ-1 inhibited phosphorylation of AKT in G361 cells. Collectively, DJ-1 overexpression could affect the proliferative and invasive capabilities of melanoma cells via regulating the PTEN/AKT pathway and apoptosis-related proteins. This study suggests that DJ-1 may be a potential target for the treatment of melanoma.
Subject(s)
Melanoma/genetics , PTEN Phosphohydrolase/metabolism , Protein Deglycase DJ-1/genetics , Proto-Oncogene Proteins c-akt/metabolism , Skin Neoplasms/genetics , Cell Line, Tumor , Cell Movement/genetics , Cell Survival/genetics , Gene Expression Regulation, Neoplastic , Gene Knockdown Techniques , Humans , Melanoma/pathology , Melanoma/surgery , Phosphorylation/genetics , Protein Deglycase DJ-1/metabolism , Signal Transduction/genetics , Skin/pathology , Skin Neoplasms/pathology , Skin Neoplasms/surgery , Up-RegulationABSTRACT
In this work, silanized and aminated lignin (SAL) was synthesized in one step and its adsorption of Congo red and Cu(II) ions in aqueous solution was explored. Lignin was subjected to amine-silanization with (3-aminopropyl) triethoxysilane (APTES). Structural characterization substantiated successful amine-silanzation of lignin and formation of multi-layer APTES intermolecular crosslinked structure. The prepared SAL (nitrogen content = 6.1%) exhibited enhanced molecular weight, thermal stability, and water- and organic solvent-resistance properties. Additionally, the present of the porous structure of particle surface and an increase in the specific surface area and zeta potential promoted the accessibility of contaminants to the effective adsorption sites of SAL. Adsorption experiments showed that both Congo red and Cu(II) ion could be completely removed at original pH value, and their adsorption involved electrostatic attraction and complexation, respectively. The adsorption isotherms and kinetics were well described by the Langmuir and pseudo-second-order equations, respectively. The results showed that SAL is a promising adsorbent for the treatment of effluents.
Subject(s)
Congo Red/chemistry , Copper/chemistry , Ions/chemistry , Lignin/chemistry , Water Purification , Adsorption , Amination , Hydrogen-Ion Concentration , Kinetics , Metals, Heavy , Molecular Structure , Molecular Weight , Osmolar Concentration , Propylamines/chemistry , Silanes/chemistry , Spectroscopy, Fourier Transform Infrared , Thermodynamics , Wastewater/chemistry , Water Pollutants, Chemical/chemistryABSTRACT
Flattened plates often show the lower or higher yield strength than initial leveled plates because tensile and compressive strains are repeatedly experienced at outer and inner walls during the pipe-forming and flattening, but reasons for the yield-strength variation after the pipe-forming are not sufficiently verified yet. In this study, ten line-pipe steels were fabricated by controlling alloying elements and finish rolling temperatures (FRTs), and the yield strength of pipe-flattened steel plates was predicted by using cyclic simulation tests, based on competing contributions of Bauschinger effect (BE) and strain hardening (SH) effect quantified from yield drop (YD) and yield rise (YR) parameters, respectively. High-FRT-treated steels (H steels) showed the lower BE and the higher SH than low-FRT-treated steels (L steels), thereby resulting in the smaller yield-strength reduction. This lower BE in the H steels was caused by the lower total boundary density, while the higher SH was caused by the higher fraction of granular bainite. According to the SH analyses between the YR parameters obtained from cyclic simulation tests and the yield ratios obtained from ordinary tensile tests, the decrease in yield-strength reduction with decreasing yield ratio was not attributed to the increase in ordinary tensile SH but to the increase in YR parameter.
ABSTRACT
PURPOSE: We investigated the expression of Nrf2 in colorectal cancer and its correlation with clinicopathological characteristics as well as mechanisms and roles of Nrf2 expression including cell signaling pathway, survival, proliferation, and migration. METHODS: Nrf2 expression was measured in 12 and 30 different colorectal cancer (CRC) tissues by western blot (WB) and immunohistochemistry (IHC), respectively. SW480 cells were used for cell proliferation and cell migration tests. The correlation between the expression of Nrf2 and clinicopathologic parameters were evaluated using the chi-square or Fisher exact test. Data are expressed as the mean ± standard deviation for 3 independent experiments. P < 0.05 was considered statistically significant. RESULTS: Analysis of WB demonstrated that Nrf2 proteins were increased in CRC tissues, and decreased in normal tissues. IHC staining showed that the Nrf2 expression was elevated in CRC tissues, compared to matched normal tissues. When SW480 cells were suppressed with small interfering RNA of Nrf2, cell viability was inhibited, and cell apoptosis was increased. These results were found along with suppression of the phosphorylated form of extracellular signal-regulated kinase 1/2 and AKT. CONCLUSION: This study suggests that overexpression of Nrf2 may be related to carcinogenesis and progression of CRC.
ABSTRACT
It has been suggested that a thyroglobulin (Tg)-R19K missense mutation may be a newly identified cause of human congenital goiter, which is surprising for this seemingly conservative substitution. Here, we have examined the intracellular fate of recombinant mutant Tg expressed in COS-7 cells. Incorporation of the R19K mutation largely blocked Tg secretion, and this mutant was approximately 90% degraded intracellularly over a 24-h period after synthesis. Before its degradation, the Tg-R19K mutant exhibited abnormally increased association with molecular chaperones BiP, calnexin, and protein disulfide isomerase, and was unable to undergo anterograde advance from the endoplasmic reticulum (ER) through the Golgi complex. Inhibitors of proteasomal proteolysis and ER mannosidase-I both prevented ER-associated degradation of the Tg-R19K mutant and increased its association with ER molecular chaperones. ER quality control around Tg residue 19 is not dependent upon charge but upon side-chain packing, because Tg-R19Q was efficiently secreted. Whereas a Tg mutant truncated after residue 174 folds sufficiently well to escape ER quality control, introduction of the R19K point mutation blocked its secretion. The data indicate that the R19K mutation induces local misfolding in the amino-terminal domain of Tg that has global effects on Tg transport and thyroid hormonogenesis.
Subject(s)
Goiter/genetics , Mutation , Thyroglobulin/genetics , Alkaloids/pharmacology , Amino Acid Substitution , Animals , Arginine/genetics , Biological Transport , Blotting, Western , COS Cells , Calnexin/metabolism , Chlorocebus aethiops , Electrophoresis, Polyacrylamide Gel , Endoplasmic Reticulum/metabolism , Endoplasmic Reticulum Chaperone BiP , Goiter/metabolism , Golgi Apparatus/metabolism , Heat-Shock Proteins/metabolism , Humans , Immunoprecipitation , Leupeptins/pharmacology , Lysine/genetics , Mice , Molecular Chaperones/metabolism , Protein Binding , Protein Disulfide-Isomerases/metabolism , Protein Folding , Signal Transduction/drug effects , Thyroglobulin/chemistry , Thyroglobulin/metabolismABSTRACT
OBJECTIVE: This study reports on early and paradoxical aggravation of hyperthyroidism, which needs long-term treatment, in patients with Graves' disease after radioactive iodine (RAI) treatment. METHODS: Five patients (0.4%) out of 1333 consecutive patients with Graves' disease who underwent RAI treatment by using an empirical fixed dose of I between January 2000 and March 2006 revisited the emergency center because of early and markedly aggravated thyrotoxic manifestations, which seemed to differ from those for radiation-induced thyroiditis. The clinical features, changes in the laboratory, and scintigraphic findings before and after RAI treatment, and long-term follow-up of these patients were reviewed retrospectively. RESULTS: The mean interval between the RAI treatment and paradoxical exacerbation of hyperthyroidism was 47.8 days (range: 28-69 days). In all five patients, the serum levels of thyroid hormones were markedly increased compared with those before the RAI treatment. The patients also exhibited an increased uptake of radioiodine or technetium-99m pertechnetate on the scintigraphy after RAI treatment. The serum levels of thyrotropin receptor antibodies were increased compared with those before the RAI treatment. Immediate and long-term treatments with antithyroid medications or second dose of RAI treatment were required in all the patients to control persistent hyperthyroidism. CONCLUSION: The early and paradoxical exacerbation of preexisting Graves' disease, as distinct from radiation-induced thyroiditis, can occur after insufficient dose of RAI treatment for Graves' disease.
Subject(s)
Graves Disease/diagnostic imaging , Iodine Radioisotopes/adverse effects , Iodine Radioisotopes/therapeutic use , Adolescent , Adult , Female , Graves Disease/pathology , Humans , Hyperthyroidism/diagnostic imaging , Hyperthyroidism/etiology , Hyperthyroidism/pathology , Iodine Radioisotopes/administration & dosage , Male , Middle Aged , Radiometry , Radionuclide Imaging , Radiopharmaceuticals , Receptors, Thyrotropin/immunology , Receptors, Thyrotropin/metabolism , Sodium Pertechnetate Tc 99m , Thyroxine/blood , Treatment FailureABSTRACT
Crude supercritical lignin (SCL) extracted from hardwood (Quercus mongolica) treated via supercritical water (SCW) oxidation was subjected to sequential fractionation with four organic solvents; five lignin fractions (F1-F4 and FIN) were thus obtained. The molecular weight (MW) of the fractionated lignins gradually increased as fractionation proceeded. However, the content of methoxyl groups and phenolic hydroxyl groups tended to decrease with increasing molecular weight of the lignins. The functional groups of SCL and the fractionated lignins were very similar based on Fourier-transform infrared analysis. The syringyl/guaiacyl ratio (S/G ratio) of the fractionated lignins increased with an increase in the MW. The thermal stability decreased with decreasing MW of the fractionated lignins, and all fractions except for F1 had a maximum degradation temperature of around 360⯰C. The glass transition temperature (Tg) of the fractions increased from 83⯰C to 137⯰C with increasing MW.
Subject(s)
Biomass , Chemical Fractionation/methods , Lignin/isolation & purification , Water/chemistry , Wood/chemistry , Lignin/chemistry , Molecular Weight , Oxidation-Reduction , Solvents/chemistry , Transition TemperatureABSTRACT
Since flattened steel sheets often show the unexpectedly lower or higher yield strength than leveled sheets, unceasing efforts have been made to accurately predict the yield strength in pipe-forming industries. In the present investigation, the yield strength of line-pipe or casing-pipe steels was predicted by competing Bauschinger effect and strain hardening occurred during the pipe-forming. Yield drop (YD) and yield rise (YR) parameters were newly defined from cyclic simulation analyses of outer and inner walls of pipes to express more reasonably the Bauschinger effect and strain hardening. The YD increased abruptly until the pre-strain of about 1%, and then saturated, while the YR increased linearly with increasing pre-strain. By combining the YD and YR, the variation in yield strength (Δσ) showed a down-and-up behavior as the Bauschinger effect and strain hardening were dominant at low and high pre-strains, respectively, and plausibly explained the relationship of Δσ and piping strain used in pipe-forming industries. According to the microstructural analyses related to the down-and-up Δσ behavior, the polygonal ferrite reduced the yield-strength reduction in the low pre-strain range, whereas the granular bainite or pearlite expanded it. This yield strength prediction coupled with microstructural analyses provide a good idea for designing and reliably predicting the yield strength of in various steel pipes.
ABSTRACT
OBJECTIVE: The exact prevalence and clinical significance of ectopic thyroid or thyroglossal duct remnant (TGDR) in the general population have not yet been fully determined despite numerous case reports. This study was prepared to assess the prevalence of TGDR in asymptomatic subjects during hypothyroidism after a total thyroidectomy for differentiated thyroid cancer (DTC) and to clarify the clinical implication. DESIGN: Tc-99m pertechnetate scintigraphy (Tc-scan) of the head and neck before radioiodine ablation therapy and whole-body and pinhole I-131 scintigraphy (I-scan) after ablation therapy were reviewed for 131 consecutive DTC patients with hypothyroidism after a total thyroidectomy. MAIN OUTCOME: Forty-four among the 131 patients (33.6%) revealed an unexpected linear or focal radioactivity at the anterior midline of the neck, suggesting the presence of TGDR. The Tc-scan and pinhole I-scan were concordant in all cases of abnormal midline neck uptake, although the planar I-scan failed to delineate TGDR due to prominent photon scattering in most cases. Preoperative enhanced neck computed tomography scan was performed in 49 patients and showed no evidence of thyroid glandular tissue separated from thyroid gland in midline of the anterior neck except 1 case. The success rate after radioiodine ablation did not differ significantly between the positive and negative TGDR patients. CONCLUSIONS: TGDR can be frequently observed in scintigraphy of hypothyroid subjects after a thyroidectomy, even when clinically unexpected. Therefore, care should be taken not to confuse the tracer uptake by TGDR with metastatic foci in I- and Tc-scans of patients with hypothyroidism after a thyroidectomy for DTC.
Subject(s)
Choristoma , Hypothyroidism/epidemiology , Thyroglossal Cyst/diagnostic imaging , Thyroid Gland/diagnostic imaging , Thyroid Neoplasms/epidemiology , Thyroidectomy , Adult , Aged , Combined Modality Therapy , Female , Humans , Hypothyroidism/diagnostic imaging , Korea/epidemiology , Lymphatic Metastasis/diagnosis , Male , Middle Aged , Prevalence , Radionuclide Imaging , Sodium Pertechnetate Tc 99m , Thyroglobulin/blood , Thyroglossal Cyst/epidemiology , Thyroid Neoplasms/diagnostic imaging , Thyroid Neoplasms/pathology , Thyrotropin/bloodABSTRACT
The Na+/H+ exchanger is responsible for maintaining the acidic tumor microenvironment through its promotion of the reabsorption of extracellular Na+ and the extrusion of intracellular H+. The resultant increase in the extracellular acidity contributes to the chemoresistance of malignant tumors. In this study, the chemosensitizing effects of cariporide, a potent Na+/H+-exchange inhibitor, were evaluated in human malignant mesothelioma H-2452 cells preadapted with lactic acid. A higher basal level of phosphorylated (p)-AKT protein was found in the acid-tolerable H-2452AcT cells compared with their parental acid-sensitive H-2452 cells. When introduced in H-2452AcT cells with a concentration that shows only a slight toxicity in H-2452 cells, cariporide exhibited growth-suppressive and apoptosis-promoting activities, as demonstrated by an increase in the cells with pyknotic and fragmented nuclei, annexin V-PE(+) staining, a sub-G0/G1 peak, and a G2/M phase-transition delay in the cell cycle. Preceding these changes, a cariporide-induced p-AKT down-regulation, a p53 up-regulation, an ROS accumulation, and the depolarization of the mitochondrial-membrane potential were observed. A pretreatment with the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002 markedly augmented the DNA damage caused by the cariporide, as indicated by a much greater extent of comet tails and a tail moment with increased levels of the p-histone H2A.X, p-ATMSer1981, p-ATRSer428, p-CHK1Ser345, and p-CHK2Thr68, as well as a series of pro-apoptotic events. The data suggest that an inhibition of the PI3K/AKT signaling is necessary to enhance the cytotoxicity toward the acid-tolerable H-2452AcT cells, and it underlines the significance of proton-pump targeting as a potential therapeutic strategy to overcome the acidic-microenvironment-associated chemotherapeutic resistance.
Subject(s)
Apoptosis/drug effects , DNA Damage , Guanidines/therapeutic use , Lung Neoplasms/drug therapy , Lung Neoplasms/pathology , Mesothelioma/drug therapy , Mesothelioma/pathology , Sulfones/therapeutic use , Cell Cycle/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Chromones/pharmacology , Culture Media , Guanidines/pharmacology , Humans , Hydrogen-Ion Concentration , Membrane Potential, Mitochondrial/drug effects , Mesothelioma, Malignant , Mitochondria/drug effects , Mitochondria/metabolism , Morpholines/pharmacology , Phosphorylation/drug effects , Proto-Oncogene Proteins c-akt/metabolism , Reactive Oxygen Species/metabolism , Sulfones/pharmacology , Tumor Suppressor Protein p53/metabolism , Up-Regulation/drug effectsABSTRACT
Reactive oxygen species (ROS) contribute to pathogenesis of many inflammatory skin diseases, including psoriasis. The aim of this study is to compare antioxidant protein expression in psoriasis vulgaris (PV) skin tissues with that in normal skin tissues in vivo and to evaluate the effects of dimethyl fumarate (DMF), used for the treatment of psoriasis, on ROS generation and apoptosis in a human keratinocyte cell line HaCaT. Compared with normal skin tissues, PV skin tissues showed increased protein oxidation as well as down-regulation of Nrf2 and its regulatory proteins such as HO-1 and AKR1C3. Using HaCaT cells to model DMF-induced pro-oxidant effects in the skin cells, we found that DMF treatment induced increased ROS levels and apoptotic cell death, as signified by increased proportion of cells with Annexin V-PE(+) staining and a sub-G0/G1 peak in the cell cycle. Preceding these changes, DMF treatment resulted in up-regulation of Nrf2, HO-1, and AKR1C3 proteins in these cells. Collectively, increased oxidative stress and impaired cellular anti-oxidant enzyme systems may participate in the pathogenesis of PV. DMF may exert an additive therapeutic efficacy in PV by attenuating the redox burden and subsequent oxidative damage to normal keratinocytes through activation of Nrf2 pathway relative to PV.