Published papers

The expression of CCAAT/enhancer-binding protein (C/EBP) family members and peroxisome proliferator-activated receptor γ (PPAR γ) is essential for the differentiation of pre-adipocyte 3T3-L1 cells into mature adipocytes induced by a combined stimulation with dexamethasone, 3-isobutyl-1-methylxanthine and insulin (DMI). We herein demonstrated that the RNA helicase DDX5, the expression of which was induced by DMI, played an important role in the adipocyte differentiation of 3T3-L1 cells. The DMI-induced accumulation of lipid droplets and expression of adipocyte markers in 3T3-L1 cells were significantly inhibited by the knockdown of DDX5. The knockdown of DDX5 interfered with the expressional induction of C/EBPδ, which was the first to be induced in the transcription factor cascade, and inhibited the subsequent expression of the other transcription factors, C/EBPβ, PPARγ and C/EBPα. DDX5 interacted with the glucocorticoid receptor (GR), which induced the expression of C/EBPδ. The knockdown of DDX5 failed to induce the nuclear translocation of GR, suggesting the essential role of DDX5 in the early stage of adipocyte differentiation. Furthermore, the reconstitution of DDX5, but not the DDX5 mutant (K144N) lacking RNA helicase activity, restored DMI-induced GR activation and adipocyte differentiation in 3T3-L1 cells in which DDX5 was knocked down, confirming that the RNA helicase activity of DDX5 is essential for adipogenesis. Collectively, these results revealed for the first time that DDX5 is necessary for GR activation and plays an essential role in early adipocyte differentiation.

Ras genes are frequently mutated in many cancer types; however, there are currently no conclusively effective anticancer drugs against Ras-induced cancer. Therefore, the downstream effectors of Ras signaling need to be identified for the development of promising novel therapeutic approaches. We previously reported that oncogenic Ras induced the expression of NF-HEV/IL-33, a member of the interleukin-1 family, and showed that intracellular IL-33 was required for oncogenic Ras-induced cellular transformation. In the present study, we demonstrated that the c-Mer proto-oncogene tyrosine kinase (MerTK), a receptor tyrosine kinase, played essential roles in oncogenic Ras/IL-33 signaling. The expression of MerTK was enhanced in transformed NIH-3T3 cells by the expression of oncogenic Ras, H-Ras (G12V), in an IL-33-dependent manner. In human colorectal cancer tissues, MerTK expression also correlated with IL-33 expression. The knockdown of IL-33 or MerTK effectively attenuated the migration of NIH-3T3 cells transformed by H-Ras (G12V) and A549, LoVo, and HCT116 cells harboring an oncogenic K-Ras mutation. Furthermore, the suppression of Ras-induced cell migration by the knockdown of IL-33 was rescued by the enforced expression of MerTK. The present results also revealed that MerTK was effectively phosphorylated in NIH-3T3 cells transformed by Ras (G12V). Ras signaling was essential for the tyrosine phosphorylation of MerTK, and the kinase activity of MerTK was indispensable for accelerating cell migration. Collectively, the present results reveal a novel role for MerTK in cancer malignancy, which may be utilized to develop novel therapeutic strategies that target Ras-transformed cells.

Presbyopia is characterized by a decline in the ability to accommodate the lens. The most commonly accepted theory for the onset of presbyopia is an age‐related increase in the stiffness of the lens. However, the cause of lens sclerosis remains unclear. With age, water microcirculation in the lens could change because of an increase in intracellular pressure. In the lens, the intracellular pressure is controlled by the Transient Receptor Potential Vanilloid (TRPV) 1 and TRPV4 feedback pathways. In this study, we tried to elucidate that administration of α‐glucosyl‐hesperidin (G‐Hsd), previously reported to prevent nuclear cataract formation, affects lens elasticity and the distribution of TRPV channels and Aquaporin (AQP) channels to meet the requirement of intracellular pressure. As a result, the mouse control lens was significantly toughened compared to both the 1% and 2% G‐Hsd mouse lens treatments. The anti‐oxidant levels in the lens and plasma decreased with age; however, this decrease could be nullified with either 1% or 2% G‐Hsd treatment in a concentration-and exposure time‐dependent manner. Moreover, G‐Hsd treatment affected the TRPV4 distribu-tion, but not TRPV1, AQP0, and AQP5, in the peripheral area and could maintain intracellular pres-sure. These findings suggest that G‐Hsd has great potential as a compound to prevent presbyopia and/or cataract formation.

Indole- and hydantoin-based derivatives both exhibit anti-inflammatory activity, suggesting that the structures of indole and hydantoin are functional for this activity. In the present study, we synthesized two types of indole-hydantoin derivatives, IH-1 (5-(1H-indole-3-ylmethylene) imidazolidine-2,4-dione) and IH-2 (5-(1H-indole-3-ylmethyl) imidazolidine-2,4-dione) and examined their effects on LPS-induced inflammatory responses in murine macrophage-like RAW264.7 cells. LPS-induced inflammatory responses were not affected by indole, hydantoin, or IH-2. In contrast, IH-1 significantly inhibited the LPS-induced production of nitric oxide (NO) and secretion of CCL2 and CXCL1 by suppressing the mRNA expression of inducible NO synthase (iNOS), CCL2, and CXCL1. IH-1 markedly inhibited the LPS-induced activation of NF-κB without affecting the degradation of IκBα or nuclear translocation of NF-κB. IH-1 markedly attenuated the transcriptional activity of NF-κB by suppressing the LPS-induced phosphorylation of the NF-κB p65 subunit at Ser276. Furthermore, IH-1 prevented the LPS-induced interaction of NF-κB p65 subunit with a transcriptional coactivator, cAMP response element-binding protein (CBP). Collectively, these results revealed the potential of the novel indole-hydantoin derivative, IH-1 as an anti-inflammatory drug.

© 2020 The Authors Presbyopia is one of the most well-known diseases of the eye, predominantly affecting the adult population after 50 years’. Due to hardening of the lens and failure of accommodative change, patients lose the ability to focus on near objects. This eye symptom is reported to be an early symptom of age-related nuclear cataract, and we have previously reported that hesperetin treatment could delay the onset of nuclear cataractogenesis induced by sodium selenite. In this study, we examined whether oral intake of α-glucosyl-hesperidin (G-Hsd), which has greater water solubility than hesperetin, could delay the onset of presbyopia. G-Hsd treatment protected lens elasticity, upregulated the mRNA expression of anti-oxidative enzymes like glutathione reductase and thioredoxin reductase 1 in the plasma and lens, and prevented premature cataract symptoms in selenite-induced cataract rat lens. Thus, the anti-presbyopic effects of G-Hsd were attributed, at least in part, to its antioxidant effects. G-Hsd represents the first oral treatment agent with anti-presbyopia and/or anti-cataract properties.

NKIRAS1 and NKIRAS2 (also called as κB-Ras) were identified as members of the atypical RAS family that suppress the transcription factor NF-κB. However, their function in carcinogenesis is still controversial. To clarify how NKIRAS acts on cellular transformation, we generated transgenic mice in which NKIRAS2 was forcibly expressed using a cytokeratin 15 (K15) promoter, which is mainly activated in follicle bulge cells. The ectopic expression of NKIRAS2 was mainly detected in follicle bulges of transgenic mice with NKIRAS2 but not in wild type mice. K15 promoter-driven expression of NKIRAS2 failed to affect the development of epidermis, which was evaluated using the expression of K10, K14, K15 and filaggrin. However, K15 promoter-driven expression of NKIRAS2 effectively suppressed the development of skin tumors induced by treatment with 7,12-dimethylbenz(a)anthracene (DMBA)/12-O-tetradecanoylphorbol 13-acetate (TPA). This observation suggested that NKIRAS seemed to function as a tumor suppressor in follicle bulges. However, in the case of oncogenic HRAS-driven cellular transformation of murine fibroblasts, knockdown of NKIRAS2 expression drastically suppressed HRAS-mutant-provoked cellular transformation, suggesting that NKIRAS2 was required for the cellular transformation of murine fibroblasts. Furthermore, moderate enforced expression of NKIRAS2 augmented oncogenic HRAS-provoked cellular transformation, whereas an excess NKIRAS2 expression converted its functional role into a tumor suppressive phenotype, suggesting that NKIRAS seemed to exhibit a biphasic bell-shaped enhancing effect on HRAS-mutant-provoked oncogenic activity. Taken together, the functional role of NKIRAS in carcinogenesis is most likely determined by not only cellular context but also its expression level.

Posterior capsule opacification (PCO), the most common complication of cataract surgery occurring in 20–50% of patients after 2–5 years of cataract surgery, is a major problem in the aging society. The epithelial-mesenchymal transition (EMT) of lens epithelial cells after cataract surgery has been proposed as a major cause of PCO. Capsaicin, widely used as a food additive and analgesic agent, is a major pungent ingredient in red pepper. Although the effect of capsaicin on EMT has been reported in cancer cells, the biological reaction of capsaicin was unique in each cell type, and there have been no reports describing its effects on EMT earlier. In this study, we demonstrated that treatment with capsaicin inhibited TGFβ2-induced EMT in vitro lens epithelial cells and ex vivo explant lens epithelial cells. Furthermore, eye drops of capsaicin inhibited the PCO model mice in vivo. Finally, we showed that capsaicin inhibited non-canonically induced Smad2/3 activation via suppression of EGFR activation and ERK phosphorylation. Our findings indicate that capsaicin and its derivatives are good candidate compounds for preventing PCO after cataract surgery.

A fusion protein, Breakpoint cluster region-Abelson (BCR-ABL) is responsible for the development of chronic myeloid leukemia (CML) and acute lymphocytic leukemia (ALL). Inhibitors against BCR-ABL are effective for the treatment of leukemia; however, a gatekeeper mutation (T315I) in BCR-ABL results in resistance to these inhibitors, which markedly impedes their efficacy. We herein demonstrated that a bis-pyridinium fullerene derivative (BPF) significantly induced apoptosis in human CML-derived K562 cells and ALL-derived SUP-B15 cells via the generation of reactive oxygen species (ROS). BPF reduced the expression of Bcr-Abl mRNA by inhibiting expression of c-Myc through ROS production. BPF also accelerated protein degradation of BCR-ABL through ROS production. Furthermore, BPF down-regulated the expression of not only BCR-ABL but also T315I-mutated BCR-ABL in ROS-dependent manner. As a result, BPF effectively induced apoptosis in transformed Ba/F3 cells expressing both BCR-ABL and T315I-mutated BCR-ABL. Collectively, these results indicate the potential of BPF as an effective leukemia drug that overcomes resistance to BCR-ABL inhibitors.

© 2018 Japan Society for Bioscience, Biotechnology, and Agrochemistry. Fatty acid monoesters of hydroxytyrosol [2-(3,4-dihydroxyphenyl)ethanol] were synthesized in two steps from tyrosol (4-hydroxyphenylethanol) by successive Candida antarctica lipase B-catalyzed chemoselective acylation on the primary aliphatic hydroxy group over phenolic hydroxy group in tyrosol, and 2-iodoxybenzoic acid (IBX)-mediated hydroxylation adjacent to the remaining free phenolic hydroxy group. Examination of their suppression effects on nitric oxide production stimulated by lipopolysaccharides in RAW264.7 cells showed that hydroxytyrosol butyrate exhibited the highest inhibition (IC 50 7.0 μM) among the tested compounds.

© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Scope: Epidemiological studies have shown that coffee consumption may be associated with a lower risk of developing several neurological disorders, including Alzheimer's disease (AD). Caffeine is a prominent candidate component underlying the preventive effects of coffee; however, the contribution of other constituents is unclear. To clarify this issue, the effect of roasting coffee beans on β-secretase (BACE1) expression in human neuroblastoma SH-SY5Y cells is investigated. Methods and results: Coffee (2%) reduces Aβ accumulation in culture medium to 80% of control levels after 24 h. Accordingly, BACE1 expression is decreased to 70% of control levels at 12 h. Experiments using cycloheximide and MG132, a proteasome inhibitor, reveal that coffee enhanced BACE1 degradation through activation of proteasomal activity. Furthermore, coffee activates cAMP-dependent protein kinase, and consequently, phosphorylation of a serine residue of proteasome 26S subunit, non-ATPase 11 (PSMD11). Pyrocatechol, a strong antioxidant known as catechol or 1,2-dihydroxybenzene, produced from chlorogenic acid during roasting, also reduces BACE1 expression by activation of proteasomal activity. Furthermore, pyrocatechol reduces Aβ production in SH-SY5Y cells. Conclusion: The data suggest that the roasting process may be crucial for the protective effects of coffee consumption in AD.

© 2018 Elsevier B.V. Hydroxytyrosol (HT) is a polyphenol contained in olives and exhibits antioxidant activity. We herein investigated the effects of HT and its derivatives, hydroxytyrosol acetate (HT-A) and hydroxytyrosol butyrate (HT-B), on the protection of neuronal cells against apoptosis induced by the Parkinson's disease-related neurotoxin 6-hydroxydopamine (6-OHDA). The pretreatment of SH-SY5Y cells with HT-B, but not HT or HT-A significantly reduced the 6-OHDA-induced generation of reactive oxygen species, activation of caspase-3, and subsequent cell death. HT-B also induced the protein expression of the transcription factor, NF-E2-related factor-2 (Nrf2) and its transcriptional activation, resulting in the up-regulated expression of heme oxygenase-1 (HO-1), which conferred neuroprotection against 6-OHDA-induced oxidative damage. Furthermore, three cysteine residues, Cys151, Cys273, and Cys288 in Kelch-like ECH-associated protein 1 (Keap1) were necessary for the HT-B-induced activation of Nrf2. Collectively, the present results demonstrated that HT-B, harboring higher fat solubility than HT and HT-A, effectively elicited adaptive responses to oxidative stress by activating the Nrf2/HO-1 axis in neuronal cells.

Copyright © Spandidos Publications 2017. All rights reserved. Cataracts are a major cause of blindness worldwide. As anti-cataract pharmaceutical therapies require long-term treatment, identifying anti-cataract compounds that are ubiquitous in the human diet, have no adverse effects and are affordable, is of paramount importance. The present study focused on hesperetin and its derived compounds, hesperetin stearic acid ester (Hes-S) and hesperetin oleic acid ester (Hes-O), in order to investigate their therapeutic potential to treat cataracts in a selenite animal model. Thirteen-day-old Sprague Dawley rats were divided into 12 groups. Animals in groups 1 and 7 were subcutaneously injected with vehicle, those in groups 2 and 8 were administered hesperetin, those in groups 3 and 9 received stearic acid, those in groups 4 and 10 were injected with oleic acid, those in groups 5 and 11 were administered Hes-S, and those in groups 6 and 12 received Hes-O (10 nmol/kg body weight on days 0, 1 and 2). Animals in groups 7 to 12 were treated with sodium selenite (20 µmol/kg body weight given 4 h following the test compound treatment on day 0) to induce cataract. On day 6, rats had less severe central opacities and lower stage cataracts than rats in the selenite treatment-only control groups. The levels of glutathione (GSH) and ascorbic acid (AsA) in lenses with selenite-induced cataracts declined to one-third of that of controls, and the reduction in GSH and AsA levels was rescued following hesperetin, Hes-S or Hes-O treatment, with concentrations remaining to 70-80% of that of controls. However, there were no changes in the plasma levels of GSH and AsA following treatments. Administration of either hesperetin or hesperetin-derived compounds prevented the reduction of chaperone activity in the lens, and rats treated with Hes-S or Hes-O treatment had significantly greater chaperone activity than hesperetin-treated rats. Collectively, these results suggested that hesperetin and hesperetin-derived compounds may be novel drug compounds that have the potential to prevent or delay the onset of cataracts.

© 2018 Elsevier Inc. Chronic myeloid leukemia (CML) and acute lymphoblastic leukemia (ALL) are hematopoietic malignancies caused by the constitutive activation of BCR-ABL tyrosine kinase. Although direct BCR-ABL inhibitors, such as imatinib, were initially successful in the treatment of leukemia, many patients developed drug resistance over time due to the gatekeeper mutation of BCR-ABL T315I. In the present study, we found that taxodione, a quinone methide diterpene isolated from Taxodium distichum, significantly induced apoptosis in human myelogenous leukemia-derived K562 cells, which were transformed by BCR-ABL. Taxodione reduced the activities of mitochondrial respiratory chain (MRC) complexes III and V, which appeared to induce the production of reactive oxygen species (ROS). N-acetylcysteine (NAC), an antioxidant agent, canceled taxodione-induced ROS production, reductions in MRC activities, particularly complex V, and apoptotic cell death. Furthermore, in K562 cells treated with taxodione, BCR-ABL and its major signaling molecules, such as STAT5 and Akt were sequestered in mitochondrial fraction, and their localization changes decrease their abilities to stimulate cell proliferation, suggesting that these actions seem to be a mechanism how taxodione functions as an anti-tumor drug. Strikingly, NAC canceled these taxodione-caused anti-cancer effects. Taxodione induced apoptosis in transformed Ba/F3 cells induced not only by BCR-ABL, but also T315I-mutated BCR-ABL through the generation of ROS. Collectively, the present results suggest that in the treatment of leukemia, taxodione has potential as a compound with high efficacy to overcome BCR-ABL T315I mutation-mediated resistance in leukemia cells.

© 2020 The Author(s) The pathophysiology of type 2 diabetes mellitus (T2DM) is characterized by not only insulin resistance, but also the abnormal regulation of glucagon secretion, suggesting that antagonizing the glucagon-induced signaling pathway has therapeutic potential in the treatment of T2DM. Although various Kampo medicines (traditional herbal medicines) are often utilized to ameliorate the symptoms of T2DM, their effects on glucagon signaling have not yet been clarified. In the present study, we examined the effects of nine types of representative Kampo formulations prescribed for T2DM on glucagon-induced CREB activation in HEK293T cells stably expressing glucagon receptor (Gcgr) and a hepatic cell line HepG2. Among these Kampo medicines, Rokumigan, Hachimijiogan, and Goshajinkigan significantly suppressed the glucagon-induced transactivation of the cAMP-responsive element (CRE)-binding protein (CREB) by inhibiting its interaction with CREB-binding protein (CBP), which led to a reduction in the expression of phosphoenolpyruvate carboxykinase (PEPCK) mRNA. Furthermore, among the crude drugs commonly contained in these three Kampo medicines, Rehmannia Root (Jio), Moutan Bark (Botampi), and Cornus Fruit (Shanzhuyu) exerted inhibitory effects on glucagon-induced CREB activation. Collectively, the present results provide a novel mechanism, the inhibition of glucagon signaling, by which Rokumigan, Hachimijiogan, and Goshajinkigan improve the symptoms of T2DM.

© 2019 Elsevier Inc. Anaplastic large cell lymphoma (ALCL) is associated with a characteristic chromosomal translocation that generates the oncogenic fusion protein, nucleophosmin-anaplastic lymphoma kinase (NPM-ALK). Methotrexate is a commonly used chemotherapeutic drug in the treatment of multiple cancers due to its inhibition of dihydrofolate reductase (DHFR), which suppresses the synthesis of DNA. In the present study, we found that low-dose methotrexate significantly induced apoptosis in transformed Ba/F3 cells expressing NPM-ALK by inhibiting the activation of signal transducer and activator of transcription factor 3 (STAT3), a critical downstream molecule of NPM-ALK. Although methotrexate prevented the phosphorylation of STAT3, it did not affect the activity of NPM-ALK. A co-treatment with folinic acid prevented the methotrexate-induced inhibition of STAT3 activation and induction of apoptosis, suggesting that methotrexate exerts its cytotoxic effects by depleting tetrahydrofolate (THF) in transformed cells by NPM-ALK. Furthermore, methotrexate induced the down-regulation of the anti-apoptotic protein, MCL-1, DNA damage, and the activation of a p53 tumor suppressor, leading to apoptosis through the inhibition of STAT3. Methotrexate significantly induced apoptosis in ALK inhibitor-resistant cells expressing the NPM-ALK mutant harboring the point mutation, G262R, and in ALCL patient-derived NPM-ALK-positive Ki-JK cells. Collectively, these results demonstrate the potential therapeutic application of methotrexate, which inhibits the activation of STAT3, to NPM-ALK-positive ALCL.

© 2019 Institute of Pharmacology, Polish Academy of Sciences Background: Inhibitors for signal transducer and activator of transcription 3 (STAT3), Stattic, BP-1-102, and LLL12 significantly induce apoptosis in transformed Ba/F3 cells expressing an oncogenic fusion protein, nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) that induces the activation of STAT3. We found that the antioxidant reagent, N-acetyl cysteine (NAC) prevented the abilities of Stattic and BP-1-102, but not LLL12 to induce apoptosis in transformed cells expressing NPM-ALK, providing a novel problem in use of STAT3 inhibitors. We herein investigated the mechanisms how NAC prevented the effects of Sttatic and BP-1-102. Methods: Ba/F3 cells expressing NPM-ALK and SUDHL-1 cells were treated with antioxidants such as NAC, Trolox or edaravone in combination with STAT3 inhibitors. Phosphorylation of STAT3, cell proliferation rate, cell viability, cell cycle, internucleosomal DNA fragmentation and the intracellular accumulation of reactive oxygen species (ROS) was investigated. The binding of STAT3 inhibitors and NAC was analyzed by LC–MS. Results: NAC but not Trolox and edaravone diminished the abilities of Stattic and BP-1-102 to induce apoptosis in cells expressing NPM-ALK. The ROS levels in cells expressing NPM-ALK were not markedly affected by the treatments with Stattic and BP-1-102 in combination with NAC, suggesting that NAC inhibited the activity of Stattic and BP-1-102 independent of its antioxidant activity. LC–MS analysis revealed that NAC directly bound to Stattic and BP-1-102. Furthermore, these NAC adducts exhibited no cytotoxicity, and failed to affect the activity of STAT3. Conclusions: NAC antagonizes the activities of Stattic and BP-1-102, which inhibit STAT3 activation by interacting with cysteine residues in STAT3.

© 2019 The Authors. Published by FEBS Press and John Wiley & Sons Ltd. It is well established that nuclear factor κB (NF-κB) acts as one of the most important transcription factors for tumor initiation and progression, as it both protects cells from apoptotic/necrotic signals and accelerates angiogenesis and tumor metastasis, which is mediated via the expression of target genes. However, it has not yet been clarified how oncogenic signals accelerate the activation of NF-κB. In the current study, we utilized untransformed NIH-3T3 cells stably harboring a κB-driven luciferase gene to show that an oncogenic mutant of Ras GTPase augmented TNFα-induced NF-κB activation. Notably, enforced expression of cyclin-dependent kinase inhibitors, such as p27Kip1 and p21Cip1, effectively canceled the accelerated activation of NF-κB, suggesting that oncogenic Ras-induced cell cycle progression is essential for the hyperactivation of NF-κB. Furthermore, we found that Ras (G12V) augmented the transcriptional activation of NF-κB, and this activation required the p38 MAP kinase. We observed that a downstream kinase of p38 MAP kinase, MSK1, was activated by Ras (G12V) and catalyzed the phosphorylation of p65/RelA at Ser-276, which is critical for its transcriptional activation. Significantly, phosphorylation of the p65/RelA subunit at Ser-276 was elevated in patient samples of colorectal cancer harboring oncogenic mutations of the K-Ras gene, and the expression levels of NF-κB target genes were drastically enhanced in several cancer tissues. These observations strongly suggest that oncogenic signal-induced acceleration of NF-κB activation is caused by activation of the p38 MAP kinase–MSK1 signaling axis and by cell cycle progression in cancer cells.

© 2020 Spandidos Publications. All rights reserved. Hesperetin is a natural flavonoid with robust antioxidant properties. Our previous study reported that hesperetin can prevent cataract formation. However, an important consideration regarding hesperetin consumption is the limited bioavailability due to its poor solubility. The present study investigated the anti-cataract effects of α-glucosyl hesperidin in vivo and in vitro using a selenite-induced cataract model. SD rats (age, 13 days) were orally administered PBS (0.2 ml) or α-glucosyl hesperidin (200 mg/kg) on days 0, 1 and 2. Sodium selenite was subcutaneously administered to the rats 4 h after the first oral administration on day 0. Antioxidant levels in the lens and blood were measured on day 6. In vitro, human lens epithelial cells were treated with sodium selenite (10 μM) and/or hesperetin (50 or 100 mM) for 24 h and analyzed for apoptosis markers using sub-G1 population and Annexin V-FITC/propidium iodide staining and DNA ladder formation. α-glucosyl hesperidin treatment significantly reduced the severity of selenite-induced cataract. The level of antioxidants was significantly reduced in the selenite-treated rats compared with in the controls; however, they were normalized with α-glucosyl hesperidin treatment. In vitro, hesperetin could significantly reduce the number of cells undergoing apoptosis induced by sodium selenite in human lens epithelial cell lines. Overall, oral consumption of α-glucosyl hesperidin could delay the onset of selenite-induced cataract, at least in part by modulating the selenite-induced cell death in lens epithelial cells.

© 2020, The Author(s). Coffee is a complex mixture of many bioactive compounds possessing anti-inflammatory properties. However, the mechanisms by which coffee exerts anti-inflammatory effects remains unclear and the active ingredients have not yet been identified. In this study, we found that coffee extract at more than 2.5%(v/v) significantly inhibited LPS-induced inflammatory responses in RAW264.7 cells and that anti-inflammatory activity of coffee required the roasting process. Interestingly, we identified pyrocatechol, a degradation product derived from chlorogenic acid during roasting, as the active ingredient exhibiting anti-inflammatory activity in coffee. HPLC analysis showed that 124 μM pyrocatechol was included in 100% (v/v) roasted coffee. A treatment with 5%(v/v) coffee extract and more than 2.5 μM pyrocatechol inhibited the LPS-induced activation of NF-κB and also significantly activated Nrf2, which acts as a negative regulator in LPS-induced inflammation. Furthermore, intake of 60% (v/v) coffee extract and 74.4 μM pyrocatechol, which is the concentration equal to contained in 60% (v/v) coffee, markedly inhibited the LPS-induced inflammatory responses in mice. Collectively, these results demonstrated that pyrocatechol, which was formed by the roasting of coffee green beans, is one of the ingredients contributing to the anti-inflammatory activity of coffee.

© 2019, Japanese Pharmacological Society. All rights reserved. Chronic myeloid leukemia (CML) and acute lymphoblastic leukemia (ALL) are caused by a fusion protein, BCR-ABL, which induces cellular transformation by activating the signaling molecules, STAT5 and Akt. The specific BCR-ABL inhibitors including imatinib, nilotinib, and dasatinib, are clinically utilized in the treatment with CML and ALL patients. Although these BCR-ABL inhibitors are initially successful in the treatment of leukemia, many patients develop drug resistance due to the appearance of the gatekeeper mutation of BCR-ABL, T315I. Recently, we found that taxodione, a quinone methide diterpene isolated from a conifer, Taxodium distichum, significantly induced apoptosis in human myelogenous leukemia-derived K562 cells, which is positive for the bcr-abl gene. Taxodione reduced the activities of mitochondrial respiratory chain complex III, leading to the production of reactive oxygen species (ROS). An antioxidant agent, N-acetylcysteine (NAC), canceled taxodione-induced ROS production and apoptotic cell death, suggesting that taxodione induced apoptosis through ROS accumulation. Furthermore, in K562 cells treated with taxodione, BCR-ABL, STAT5 and Akt were sequestered in mitochondrial fraction, and their localization changes decrease their abilities to stimulate cell proliferation. Strikingly, NAC canceled these taxodione-caused inhibition of BCR-ABL, STAT5 and Akt. In addition, taxodione significantly induced apoptosis in transformed Ba/F3 cells by not only BCR-ABL but also T315I-mutated BCR-ABL through the generation of ROS, suggesting that taxodione has potential as anti-tumor drug with high efficacy to overcome BCR-ABL T315I mutation-mediated resistance in leukemia cells. It’s also expected that these knowledge becomes an important clue in the development of anti-cancer drugs against the broad range of tumors.