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Amino acid deprivation in cancer cells with compensatory autophagy induction increases sensitivity to autophagy inhibitors
No full textInhibition of autophagy is an important strategy in cancer therapy. However, prolonged inhibition of certain autophagies in established cancer cells may increase therapeutic resistance, though the underlying mechanisms of its induction and enhancement remain unclear. This study sought to elucidate the mechanisms of therapeutic resistance through repeated autophagy inhibition and amino acid deprivation (AD) in an in vitro model of in vivo chronic nutrient deprivation associated with cancer cell treatment. In the human cervical cancer cell line HeLa and human breast cancer cell line MCF-7, initial extracellular AD induced the immediate expression of endosomal microautophagy (eMI). However, repeated inhibition of eMI with U18666A and extracellular AD induced macroautophagy (MA) to compensate for reduced eMI, simultaneously decreasing cytotoxicity. Here, hyperphosphorylated JNK was transformed into a hypophosphorylated state, suggesting conversion of the cell death signal to a survival signal. In a nutrient medium, cell death could not be induced by MA inhibition. However, since LAT1 inhibitors induce intracellular AD, combining them with MA and eMI inhibitors successfully promoted cell death in resistant cells. Our study identified a novel therapeuic approach for promoting cell death and addressing therapeutic resistance in cancers under autophagy-inhibitor treatment.journal articl
Structure-activity relationship studies of pyrogallol as a calcineurin/NFAT signaling suppressor
Get PDFPreviously, we have shown that pyrogallol alleviated nasal symptoms and suppressed IL-9 gene up-regulation in allergy model rats by inhibiting calcineurin/NFAT signaling. As pyrogallol has antioxidative activity, it may be responsible for inhibiting calcineurin/NFAT signaling-mediated IL-9 gene expression. However, the relationship between antioxidative activity and suppression of IL-9 gene expression has not been elucidated yet. Here, we conducted the structure-activity relationship studies of pyrogallol and its structurally related compounds to understand the mechanism of IL-9 gene suppression by pyrogallol. 2, 2-Diphenyl-1-picrylhydrazyl radical scavenging assay showed that the antioxidative activity of catechol, resorcinol, phloroglucinol, and gallic acid is 60.1%, 10.4%, 18.8%, and 113.5% of pyrogallol, respectively. Catechol, resorcinol, and phloroglucinol did not suppress NFAT dephosphorylation. Gallic acid suppressed dephosphorylation of NFAT. Gallic acid also suppressed ionomycin-induced up-regulation of IL-9 gene expression with the IC50 value of 82.6 μM. However, catechol, resorcinol and phloroglucinol showed no suppressive activity. In addition, using gallic acid-immobilized beads, we isolated and identified Poly(U)-binding-splicing factor 60 (PUF60) as a pyrogallol binding protein. These results suggest that the antioxidative activity of pyrogallol is not likely to be the mechanism of IL-9 gene suppression. Data also suggest that PUF60 is one of its target molecules responsible for the suppression of calcineurin/NFAT signaling by pyrogallol.journal articl
Striatal parvalbumin interneurons are activated in a mouse model of cerebellar dystonia
Get PDFDystonia is thought to arise from abnormalities in the motor loop of the basal ganglia; however, there is an ongoing debate regarding cerebellar involvement. We adopted an established cerebellar dystonia mouse model by injecting ouabain to examine the contribution of the cerebellum. Initially, we examined whether the entopeduncular nucleus (EPN), substantia nigra pars reticulata (SNr), globus pallidus externus (GPe) and striatal neurons were activated in the model. Next, we examined whether administration of a dopamine D1 receptor agonist and dopamine D2 receptor antagonist or selective ablation of striatal parvalbumin (PV, encoded by Pvalb)-expressing interneurons could modulate the involuntary movements of the mice. The cerebellar dystonia mice had a higher number of cells positive for c-fos (encoded by Fos) in the EPN, SNr and GPe, as well as a higher positive ratio of c-fos in striatal PV interneurons, than those in control mice. Furthermore, systemic administration of combined D1 receptor agonist and D2 receptor antagonist and selective ablation of striatal PV interneurons relieved the involuntary movements of the mice. Abnormalities in the motor loop of the basal ganglia could be crucially involved in cerebellar dystonia, and modulating PV interneurons might provide a novel treatment strategy.doctoral thesi
Accumulated melanin in molds provides wavelength‑dependent UV tolerance
Get PDFFungal contamination poses a serious threat to public health and food safety because molds can grow under stressful conditions through melanin accumulation. Although ultraviolet (UV) irradiation is popular for inhibiting microorganisms, its effectiveness is limited by our insufficient knowledge about UV tolerance in melanin-accumulating molds. In this study, we first confirmed the protective effect of melanin by evaluating the UV sensitivity of young and mature spores. Additionally, we compared UV sensitivity between spores with accumulated melanin and spores prepared with melanin biosynthesis inhibitors. We found that mature spores were less UV-sensitive than young spores, and that reduced melanin accumulation by inhibitors led to reduced UV sensitivity. These results suggest that melanin protects cells against UV irradiation. To determine the most effective wavelength for inhibition, we evaluated the wavelength dependence of UV tolerance in a yeast (Rhodotorula mucilaginosa) and in molds (Aspergillus fumigatus, Cladosporium halotolerans, Cladosporium sphaerospermum, Aspergillus brasiliensis, Penicillium roqueforti, and Botrytis cinerea). We assessed UV tolerance using a UV-light emitting diode (LED) irradiation system with 13 wavelength-ranked LEDs between 250 and 365 nm, a krypton chlorine (KrCl) excimer lamp device, and a low pressure (LP) Hg lamp device. The inhibition of fungi peaked at around 270 nm, and most molds showed reduced UV sensitivity at shorter wavelengths as they accumulated pigment. Absorption spectra of the pigments showed greater absorption at shorter wavelengths, suggesting greater UV protection at these wavelengths. These results will assist in the development of fungal disinfection systems using UV, such as closed systems of air and water purification.doctoral thesi
Soy isoflavone genistein attenuates the efficacy of immune checkpoint therapy in C57BL/6 mice inoculated with B16F1 melanoma and a high PD-L1 expression level reflects tumor resistance
Get PDFImmune checkpoint therapy has been shown to be an effective therapy for many types of tumors. Much attention has been paid to the development of an effector target would be helpful for immune checkpoint therapy. Genistein has been shown to have an anti-tumor effect both in vitro and in vivo. In this study, we examined the effect of genistein on immune checkpoint blockade therapy against B16F1 melanoma tumors. Mice treated with genistein or anti-programmed death (PD)-1 antibody showed a significant decrease in tumor growth. However, treatment with genistein had no effect on or attenuated the efficacy of immune checkpoint therapy. The percentages of T cell receptor (TCR)β+CD4+ and TCRβ+CD8+ cells and the concentrations of interferon-γ and tumor necrosis factor-α in tumor tissue were not different among the experimental groups. A significant difference was also not found in microbe composition. Interestingly, a high expression level of PD-ligand (L)1 closely reflected the outcome of therapy by genistein or anti-PD-1 antibody. The study showed that a combination of genistein treatment does not improve the effect of immune blockade therapy. It also showed that a high PD-L1 expression level in tumors is a good prediction maker for the outcome of tumor therapy.journal articl
Effects of D-allose on ATP production and cell viability in neonatal rat cardiomyocytes
Get PDF2-Deoxy-D-glucose (2DG) induces anticancer effects through glycolytic inhibition but it may raise the risk of arrhythmia. The rare monosaccharide D-allose also has anticancer properties, but its cardiac effects are unknown. We examined the effects of D-allose on adenosine triphosphate (ATP) production in neonatal rat cardiomyocytes. We showed that 25 mM D-allose selectively reduced glycolytic ATP, but had minimal impact on mitochondrial ATP, while 1 mM 2DG strongly inhibited both. Furthermore, D-allose had less impact on cell viability and was less cytotoxic than 2DG; neither compound caused apoptosis. Thus, D-allose selectively diminished glycolytic ATP production with no apparent effects on cardiomyocytes.journal articl
Insertion of a spacer block translates the tibia anteriorly during evaluation of soft tissue balance in cruciate-retaining total knee arthroplasty
Get PDFBackground: Soft tissue balance is an important determinant of the outcome of total knee arthroplasty (TKA). However, there are differences in the joint gap and ligament balance between the osteotomized femoral and tibial surfaces and those after TKA. The aim of this study was to compare the relationship between the femur and tibia at insertion of a spacer block with that after cruciate-retaining (CR) TKA.
Methods: Thirty knees in 30 patients (26 women, 4 men) who underwent primary CR TKA with a navigation system were enrolled. Mean age at surgery was 76.3 (range, 63–87) years. After osteotomy of the femur and tibia, the flexion–extension gap and ligament balance were evaluated using a spacer block. The location of the tibial center in relation to the femoral center in the sagittal plane calculated from navigation data at insertion of an appropriately sized spacer block in knee flexion was compared with that after CR TKA using the paired t-test.
Results: The mean sagittal location of the tibial center relative to the femoral center in knee flexion was 5.16 (range, −2.4, 16.3) mm at insertion of the spacer block and 6.60 (range, −1.4, 15.1) mm after CR TKA, and this difference was significant (p = 0.016).
Conclusion: Assessment of soft tissue balance using a spacer block in CR TKA during knee flexion changes the location of the tibia. Surgeons should be aware of the potential for overestimating the postoperative flexion gap in CR TKA when using a spacer block to assess the flexion gap.doctoral thesi
Lipoprotein (a) is a risk factor of aortic valve calcification in patients with a risk of atherosclerosis
Get PDFAortic valve calcification (AVC), which causes aortic stenosis (AS), is more common in elderly persons. Controlling for conventional risk variables did not, however, reduce the incidence of AS. Thus, residual risk factors of AS should be identified. We enrolled 513 patients who underwent coronary angiography with computed tomography because of suspicion of coronary artery disease (CAD) or ruling out of CAD before aortic valve replacement. Calcium volume was calculated with a commercially available application. Conventional and lipid-related risk factors including serum levels of Lp(a) were evaluated for all patients. Calcium volume and Lp(a) levels were significantly higher in patients who underwent aortic valve replacement than in those who did not. A single regression analysis showed that the calcium volume was positively associated with age and the Lp(a) levels and negatively associated with the estimated glomerular filtration rate. No statistical significance was observed for other risk factors, including oxidized low-density lipoprotein, omega-3 fatty acids levels. The multiple regression analysis revealed that age (P < 0.001), female sex (P < 0.05), Lp(a) (P < 0.01), and hemoglobin A1c (P < 0.01) were determinants of the calcium volume. The area under the curve in receiver operating characteristic analysis of Lp(a) for implementation of AVR was 0.65 at an Lp(a) cut-off level of 16 mg/dL. In conclusion, the serum Lp(a) level is a potent risk factor of AVC in patients with high risk of atherosclerosis.doctoral thesi
Discretizing low-intensity whole-body vibration into bouts with short rest intervals promotes bone defect repair in osteoporotic mice
Get PDFContinuous administration of low-intensity whole-body vibration (WBV) gradually diminishes bone mechanosensitivity over time, leading to a weakening of its osteogenic effect. We investigated whether discretizing WBV into bouts with short rest intervals was effective in enhancing osteoporotic bone repair. Ten-week-old female mice were ovariectomized and underwent drill-hole defect surgery (day 0) on the right tibial diaphysis at 11 weeks of age. The mice underwent one of three regimens starting from day 1 for 5 days/week: continuous WBV at 45 Hz and 0.3 g for 7.5 minutes/day (cWBV); 3-second bouts of WBV at 45 Hz, 0.3 g followed by 9-second rest intervals, repeated for 30 minutes/day (rWBV); or a sham treatment. Both the cWBV and rWBV groups received a total of 20,250 vibration cycles per day. On either day 7 or 14 post-euthanasia (n = 6/group/timepoint), the bone and angiogenic vasculature in the defect were CT imaged using synchrotron lights. By day 14, the bone repair was most advanced in the rWBV group, showing a higher bone volume fraction and a more uniform mineral distribution compared with the sham group. The cWBV group exhibited an intermediate level of bone repair between the sham and rWBV groups. The rWBV group had a decrease in large-sized angiogenic vessels, while the cWBV group showed an increase in such vessels. In conclusion, osteoporotic bone repair was enhanced by WBV bouts with short rest intervals, which may potentially be attributed to the improved mechanosensitivity of osteogenic cells and alterations in angiogenic vasculature.journal articl
