bims-noxint Biomed News
on NADPH oxidases in tumorigenesis
Issue of 2019‒08‒04
eleven papers selected by
Laia Caja Puigsubira
Uppsala University

  1. Phytother Res. 2019 Aug 02.
    Bai J, Wang Y, Zhu X, Shi J.
      Diabetic nephropathy (DN) is one of the major complications of diabetes mellitus. The progression of DN has been found to be associated with high glucose (HG)-induced oxidative stress and inflammation in diabetes mellitus. Eriodictyol is a flavonoid that possesses antioxidant and anti-inflammatory effects. However, the effect of eriodictyol on DN remains unknown. In the present study, we evaluated the role of eriodictyol in mesangial cells (MCs) in response to HG condition. The results showed that eriodictyol repressed cell proliferation of HG-stimulated MCs. Treatment with eriodictyol attenuated oxidative stress, which was evidenced by increased superoxide dismutase activity as well as decreased production of reactive oxygen species (ROS) and malondialdehyde. Besides, eriodictyol suppressed the expressions of two NADPH oxidase (NOX) isoforms, NOX2 and NOX4, which are responsible for the generation of ROS. Eriodictyol suppressed the production of extracellular matrix proteins including fibronectin and Collagen IV, as well as the secretion of inflammatory cytokines including TNF-α, IL-1β, and IL-6 in HG-induced MCs. Moreover, the HG-induced activation of Akt/NF-κB pathway was mitigated by eriodictyol. In conclusion, eriodictyol protected MCs from HG stimulation though inhibition of Akt/NF-κB pathway.
    Keywords:  Akt/NF-κB pathway; diabetic nephropathy (DN); eriodictyol; high glucose (HG); inflammation; mesangial cells (MCs); oxidative stress
  2. Cell Rep. 2019 Jul 30. pii: S2211-1247(19)30865-4. [Epub ahead of print]28(5): 1282-1295.e8
    Ohata H, Shiokawa D, Obata Y, Sato A, Sakai H, Fukami M, Hara W, Taniguchi H, Ono M, Nakagama H, Okamoto K.
      Cancer stem cells (CSCs) are associated with the refractory nature of cancer, and elucidating the targetable pathways for CSCs is crucial for devising innovative antitumor therapies. We find that the proliferation of CSC-enriched colon spheroids from clinical specimen is dependent on mTORC1 kinase, which is activated by reactive oxygen species (ROS) produced by NOX1, an NADPH oxidase. In the spheroid-derived xenograft tumors, NOX1 is preferentially expressed in LGR5-positive cells. Dependence on NOX1 expression or mTOR kinase activity is corroborated in the xenograft tumors and mouse colon cancer-derived organoids. NOX1 co-localizes with mTORC1 in VPS41-/VPS39-positive lysosomes, where mTORC1 binds to S100A9, a member of S100 calcium binding proteins, in a NOX1-produced ROS-dependent manner. S100A9 is oxidized by NOX1-produced ROS, which facilitates binding to mTORC1 and its activation. We propose that NOX1-dependent mTORC1 activation via S100A9 oxidation in VPS41-/VPS39-positive lysosomes is crucial for colon CSC proliferation and colon cancer progression.
    Keywords:  NOX1; ROS; S100A9; cancer stem cells; colon cancer; mTORC1
  3. Radiat Res. 2019 Aug 02.
    Chung EJ, Reedy JL, Kwon S, Patil S, Valle L, White AO, Citrin DE.
      Radiation-induced pulmonary fibrosis (RIPF) is a chronic, progressive complication of therapeutic irradiation of the thorax. It has been suggested that senescence of type II pneumocytes (AECIIs), an alveolar stem cell, plays a role in the development of RIPF through loss of replicative reserve and via senescent AECII-driven release of proinflammatory and profibrotic cytokines. Within this context, we hypothesized that arachidonate 12-lipoxygenase (12-LOX) is a critical mediator of AECII senescence and RIPF. Treatment of wild-type AECIIs with 12S-hydroxyeicosateraenoic acid (12S-HETE), a downstream product of 12-LOX, was sufficient to induce senescence in a NADPH oxidase 4 (NOX4)-dependent manner. Mice deficient in 12-LOX exhibited reduced AECII senescence, pulmonary collagen accumulation and accumulation of alternatively activated (M2) macrophages after thoracic irradiation (5 × 6 Gy) compared to wild-type mice. Conditioned media from irradiated or 12S-HETE-treated primary pneumocytes contained elevated levels of IL-4 and IL-13 compared to untreated pneumocytes. Primary macrophages treated with conditioned media from irradiated AECII demonstrated preferential M2 type polarization when AECIIs were derived from wild-type mice compared to 12-LOX-deficient mice. Together, these data identified 12-LOX as a critical component of RIPF and a therapeutic target for radiation-induced lung injury.
  4. Med Hypotheses. 2019 Aug;pii: S0306-9877(19)30041-6. [Epub ahead of print]129 109249
    Stuart JA, Aibueku O, Bagshaw O, Moradi F.
      Although once considered by biologists almost exclusively for their toxicity, reactive oxygen (ROS) and nitrogen (RNS) species produced within normal cells under baseline physiological conditions are now appreciated as redox regulators of a wide range of protein functions. Two families of enzymes, the NADPH oxidases (NOXs) and nitric oxide synthases (NOSs), are major sources of ROS/RNS from molecular oxygen. Aquaporins (AQPs) are membrane channels capable of transporting some ROS/RNS, in particular hydrogen peroxide and perhaps nitric oxide. The activities of all these enzymes and channels are sensitive to variations in oxygen levels within the physiological range experienced by cells in the human body. Since ROS/RNS have important physiological roles and their endogenous production is affected by oxygen levels, we hypothesize that the synthesis of these proteins is increased at lower oxygen levels within the physiological range of most human cells in vivo, i.e. 2-5%, in order to facilitate the maintenance of ROS/RNS production rates. We further postulate that this is achieved, at least in part, by transcriptional stimulation mediated by the activity of hypoxia inducible factors (HIFs), which are strongly regulated by oxygen levels over the same range of oxygen. Here we survey the evidence supporting this hypothesis, including induction of expression of NOXs, NOSs, and AQPs at lower oxygen levels, presence of hypoxia response elements in the corresponding human genes, and evidence from chromatin immunoprecipitation (ChIP) experiments that HIF-1 and/or HIF-2 bind these regions. We find a significant amount of empirical data supporting the hypothesis that HIFs could function as physiological regulators of ROS/RNS homeostasis in the normoxic range in human cells.
  5. Cell Death Differ. 2019 Jul 31.
    Gao Q, Zhang G, Zheng Y, Yang Y, Chen C, Xia J, Liang L, Lei C, Hu Y, Cai X, Zhang W, Tang H, Chen Y, Huang A, Wang K, Tang N.
      Solute carrier family 27 member 5 (SLC27A5/FATP5) is involved in fatty acid transport and bile acid metabolism; however, little is known about its role in human diseases. Here, we first show that SLC27A5 expression is downregulated in hepatocellular carcinoma (HCC) by DNA hypermethylation, and reduced SCL27A5 expression contributes to tumor progression and poor prognosis. Both gain- and loss-of-function studies demonstrated that SLC27A5 has an antiproliferative effect on HCC cells in vitro and in vivo. Knockout of SLC27A5 increases polyunsaturated lipids, leading to increased NADP+/NADPH ratio, ROS production as well as lipid peroxidation and the subsequent accumulation of 4-hydroxy-2-nonenal (4-HNE) in hepatoma cells. Mass spectrometry analysis found that 4-HNE directly modifies cysteine residues (Cys513, 518) on KEAP1, thus leading KEAP1/NRF2 pathway activation and increases the expression levels of NRF2 target genes, such as TXNRD1. Further, SLC27A5 expression negatively correlates with TXNRD1 expression in hepatoma cells and clinical HCC samples, and blockade of NRF2/TXNRD1 using genetic approaches or inhibitors sensitizes SLC27A5-deficient hepatoma cells to sorafenib treatment. Collectively, we demonstrated that SLC27A5 acts as a novel tumor suppressor by suppressing TXNRD1 expression via the KEAP1/NRF2 pathway in HCC. Combination therapy of sorafenib and NRF2/TXNRD1 inhibitors may be a promising strategy in personalized HCC treatment.
  6. Sci Rep. 2019 Aug 01. 9(1): 11183
    Nchienzia H, Liao MC, Zhao XP, Chang SY, Lo CS, Chenier I, Ingelfinger JR, Chan JSD, Zhang SL.
      Hedgehog interacting protein (Hhip) is essential for islet formation and beta-cell proliferation during pancreatic development; abnormally elevated Hhip expression has been linked to human pancreatitis. Here, we investigate the role of Hhip in modulating insulin secretion in adult Hhip mice (Hhip +/- vs. Hhip+/+) fed high fat diets (HFD). Both sexes of HFD-Hhip +/+ mice developed impaired glucose intolerance, that was only ameliorated in male HFD-Hhip +/- mice that had high levels of circulating plasma insulin, but not in female HFD-Hhip +/- mice. HFD stimulated Hhip gene expression, mainly in beta cells. Male HFD-Hhip +/+ mice had more large islets in which insulin content was reduced; islet architecture was disordered; and markers of oxidative stress (8-OHdG and Nox 2) were increased. In contrast, male HFD-Hhip +/- mice had more small islets with increased beta cell proliferation, enhanced GSIS, less oxidative stress and preserved islet integrity. In vitro, recombinant Hhip increased Nox2 and NADPH activity and decreased insulin-positive beta cells. siRNA-Hhip increased GSIS and abolished the stimulation of sodium palmitate (PA)-BSA on Nox2 gene expression. We conclude that pancreatic Hhip gene inhibits insulin secretion by altering islet integrity and promoting Nox2 gene expression in beta cells in response to HDF-mediated beta cell dysfunction, a novel finding.
  7. Biol Chem. 2019 Jul 29. pii: /j/bchm.ahead-of-print/hsz-2019-0160/hsz-2019-0160.xml. [Epub ahead of print]
    Ehrenfeld V, Fulda S.
      Imbalances in redox homeostasis have been described to be involved in the development, progression and relapse of leukemia. As the thioredoxin (Trx) system, one of the major cellular antioxidant networks, has been implicated in acute lymphoblastic leukemia (ALL), we investigated the therapeutic potential of Trx inhibition in ALL. Here, we show that the Trx inhibitor PX-12 reduced cell viability and induced cell death in a dose- and time-dependent manner in different ALL cell lines. This antileukemic activity was accompanied by an increase in reactive oxygen species (ROS) levels and enhanced PRDX3 dimerization. Pre-treatment with the thiol-containing ROS scavenger N-acetylcysteine (NAC), but not with non-thiol-containing scavengers α-tocopherol (α-Toc) or Mn(III)tetrakis(4-benzoic acid) porphyrin chloride (MnTBAP), significantly rescued PX-12-induced cell death. Furthermore, PX-12 triggered activation of BAK. Importantly, knockdown of BAK reduced PX-12-stimulated ROS production and cell death. Similarly, silencing of NOXA provided significant protection from PX-12-mediated cell death. The relevance of mitochondria-mediated, caspase-dependent apoptosis was further supported by data showing that PX-12 triggered cleavage of caspase-3 and that addition of the broad-range caspase inhibitor carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]-fluoromethylketone (zVAD.fmk) potently blocked cell death upon PX-12 treatment. This study provides novel insights into the mechanisms of PX-12-induced cell death in ALL and further highlights the therapeutic potential of redox-active compounds in ALL.
    Keywords:  ALL; PX-12; apoptosis; mitochondria; reactive oxygen species; thioredoxin system
  8. Anticancer Res. 2019 Aug;39(8): 4405-4410
    Ashizawa N, Shimizu H, Sudo M, Furuya S, Akaike H, Hosomura N, Kawaguchi Y, Amemiya H, Kawaida H, Inoue S, Kono H, Ichikawa D.
      BACKGROUND/AIM: Recent studies have reported the involvement of NADPH oxidases (NOXs) in tumor progression. However, the role of NOX5 in colon cancer is unclear. We examined the clinical significance of NOX5 expression in colon cancer.PATIENTS AND METHODS: NOX5 expression was evaluated by immunohistochemistry in 119 patients with stage II or III colon cancer, and the relationship between NOX5 expression and clinicopathological data was analyzed.
    RESULTS: Of all tissues, 39.5% were negative and 60.5% were positive for NOX5 expression. Positive expression was significantly associated with undifferentiated histology (p=0.037) and lymph node metastasis (p=0.023). The 5-year progression-free survival rate of NOX5-positive patients was significantly worse than that of NOX5-negative patients (p=0.046). The rates of local recurrence observed in NOX5-positive patients were higher than that in NOX5-negative patients.
    CONCLUSION: NOX5 expression may be related to poor prognostic factors and could be useful as a prognostic biomarker.
    Keywords:  NADPH oxidase 5; colon cancer; immunohistochemistry
  9. Free Radic Biol Med. 2019 Jul 29. pii: S0891-5849(19)30697-5. [Epub ahead of print]
    Zhang WX, Tai GJ, Li XX, Xu M.
      BACKGROUND: Neointima hyperplasia is the pathological basis of atherosclerosis and restenosis which have been associated with diabetes mellitus (DM). It is controversial for linagliptin and metformin to protect against vascular neointimal hyperplasia caused by DM. Given the combined therapy of linagliptin and metformin in clinical practice, we investigated whether the combination therapy inhibited neointimal hyperplasia in the carotid artery in diabetic rats.METHODS AND RESULTS: Neointima hyperplasia in the carotid artery was induced by balloon-injury in the rats fed with high fat diet (HFD) combined with low dose streptozotocin (STZ) administration. In vitro, vascular smooth muscle cells (VSMCs) were incubated with high glucose (HG, 30 mM) and the proliferation, migration, apoptosis and collagen deposition were analyzed in VSMCs. We found that the combined therapy, not the monotherapy of linagliptin and metformin significantly inhibited the neointima hyperplasia and improved the endothelium-independent contraction in the balloon-injured cardia artery of diabetic rats, which was associated with the inhibition of superoxide (O2-.) production in the cardia artery. In vitro, HG-induced VSMC remodeling was shown as the remarkable upregulation of PCNA, collagan1, MMP-9, Bcl-2 and migration rate as well as the decreased apoptosis rate. Such abnormal changes were dramatically reversed by the combined use of linagliptin and metformin. Moreover, the AMP-activated protein kinase (AMPK)/Nox4 signal pathway was found to mediate VSMC remodeling responding to HG. Linagliptin and metformin were synergistical to target AMPK/Nox4 signal pathway in VSMCs incubated with HG and in the cardia artery of diabetic rats, which was superior to the monotherapy.
    CONCLUSIONS: We demonstrated that the potential protection of the combined use of linagliptin and metformin on VSMC remodeling through AMPK/Nox4 signal pathway, resulting in the improvement of neointima hyperplasia in diabetic rats. This study provided new therapeutic strategies for vascular stenosis associated with diabetes.
    Keywords:  AMPK; Diabetes; Linagliptin; Metformin; Neointima hyperplasia; Nox4
  10. Free Radic Res. 2019 Aug 02. 1-141
    Jiang Y, Xu , Yu L, Xu X, Feng C, Li J.
      Enteric glial cells (EGCs), one main cell population of the enteric nervous system (ENS), play a major role in regulating intestinal barrier function.Clostridium difficile toxin B(TcdB) is the major virulence factor produced by Clostridium difficile ( C. difficile ) and estimated to be toxic to EGCs by inducing cell death, cell cycle arrest and inflammatory cytokine production; however, the detailed mechanism for such effect is still unclear. In this study, we further evaluated the toxic effect of TcdB on EGCs and the involvement of NADPH oxidases in such process using the rat-transformed EGCs (CRL-2690). The results showed thatNOX4was activated by TcdB in EGCs and functioned as the major factor causing cytotoxicity and cell apoptosis. Mechanically, NOX4-generated H2O2 was the inducer of oxidative stress, Ca2+ homeostasis disorder and ER stress in EGCs upon TcdB treatment, and NOX4 inhibition protected EGCs against TcdB toxicity via attenuating these dysfunctions.These findings contribute to our understanding of the mechanism by which TcdB affects EGCs and suggest the potential value of NOX4 inhibition for treatment against C. difficile infection.
    Keywords:   toxin B; NOX4; endoplasmic reticulum stress; enteric glial cells; oxidative stress
  11. Metabolism. 2019 Jul 25. pii: S0026-0495(19)30145-3. [Epub ahead of print] 153948
    Jiang Z, Zhou J, Li T, Tian M, Lu J, Jia Y, Wan G, Chen K.
      Moderate or low level hydrogen peroxides has been shown to play an important role in vascular smooth muscle cell (VSMC) function, in which the polymerase DNA-directed interacting protein 2 (poldip2), functioned as a key regulator of NOX4 activity. In current study, we unexpectedly found that type 2 diabetes mellitus (T2DM) substantilly suppresses the hepatic poldip2 expression, and that the hepatic deficiency of poldip2 may be correlated with dysregulation of hepatic cholestrol and plasma triglycerides. In cultured hepatocytes, we found that both insulin and leptin may inhibit hepatic expression of poldip2 under high glucose concentration, but these suppressions were totally abolished under normoglycemic condition. POLDIP2 siRNA knockdown significantly impaired the H2O2 induction by insulin or leptin under normoglycemic condition, contributing the accumulation of cholesterol in cultured liver cells. The in vivo restoration of hepatic poldip2 expression in T2DM mice remarkably rescued the moderate H2O2 generation in livers versus control mice, resulting in significant amelioration of hepatic cholesterol accumulation and plasma triglyceride levels. Importantly, the moderate induction of H2O2 in livers dramatically improved the hepatic PI3K-C1/AKT signaling or dampened PI3K-C2γ/AKT signaling through suppression of PTEN and PTP1B activities, thereby inhibiting the hepatic expression of HMGCR and SREBP2 for cholesterol synthesis. Moreover, the restitution of hepatic poldip2 expression in diabetic mice significantly lowered the VLDL-cholesterol production rate, and substantially suppressed PEPCK and G6Pase expressions for gluconeogenesis, thus significantly improving the plasma insulin and glucose levels, and ITT and GTT outcomes in diabetic mice. Our findings suggest that hepatic dysregulation of poldip2 may contribute to diabetic dyslipidemia and hyperglycemia.