Search

Background: Subacute myelo‐optico‐neuropathy (SMON) is a neurological disorder associated with the administration of clioquinol, particularly at very high doses. Although clioquinol has been used worldwide, there was an outbreak of SMON in the 1950s–1970s in which the majority of cases were in Japan, prompting speculation that the unique genetic background of the Japanese population may have contributed to the development of SMON. Recently, a possible association between loss‐of‐function polymorphisms in NQO1 and the development of SMON has been reported. In this study, we analyzed the relationship between NQO1 polymorphisms and SMON in Japan. Methods: We analyzed 125 Japanese patients with SMON. NQO1 loss‐of‐function polymorphisms (rs1800566, rs10517, rs689452, and rs689456) were evaluated. The allele frequency distribution of each polymorphism was compared between the patients and the healthy Japanese individuals (Human Genomic Variation Database and Integrative Japanese Genome Variation Database), as well as our in‐house healthy controls. Results: The frequencies of the loss‐of‐function NQO1 alleles in patients with SMON and the normal control group did not differ significantly. Conclusion: We conclude that known NQO1 polymorphisms are not associated with the development of SMON. [ABSTRACT FROM AUTHOR]

Background: Subacute myelo‐optico‐neuropathy (SMON) is a severe neurological disorder associated with clioquinol administration, which frequently occurred in Japan during the 1950s and 1960s. The unique genetic background of the Japanese population is considered to be strongly involved in the development of this neurological disease. Recently, genetic variants of ABCC4 (OMIM: 605250) and ABCC11 (OMIM: 607040), which are particularly common in the Japanese population, were suggested as possible genetic susceptibility factors for the development of SMON. Methods: We analyzed 125 Japanese SMON patients who provided consent for this study. Patient DNA was collected from peripheral blood, and genetic analysis was performed for ABCC4 rs3765534 (c.2268G>A, p.Glu857Lys) and ABCC11 rs17822931 (c.538G>A, p.Gly180Arg) polymorphisms using the Sanger sequencing method and/or TaqMan PCR method. The frequency distribution of each polymorphism was compared with that in healthy Japanese people recorded in two genomic databases (Human Genomic Variation Database and Integrative Japanese Genome Variation Database), and each genotype was compared with the clinical features of patients. Results: The frequencies of ABCC4 rs3765334 and ABCC11 rs17822931 polymorphisms in SMON patients and healthy Japanese people were not significantly different in the multifaceted analysis. Conclusion: We conclude that the ABCC4 rs3765334 and ABCC11 rs17822931 polymorphisms are not associated with the development of SMON. [ABSTRACT FROM AUTHOR]

The involvement of superoxide‐generating NADPH oxidase (NOX) in the cytotoxic effects of cigarette smoke extracts has been documented. However, the underlying molecular mechanisms and NOX isoform involved have not been fully clarified. Among the different NADPH oxidase isoforms identified so far, NOX1 and NOX4 were found to be expressed in rat H9c2 cardiomyocytes. When H9c2 cells were exposed to acrolein or methyl vinyl ketone (MVK), major toxic components of cigarette smoke extracts, a dose‐dependent decline in cell viability was observed. Unexpectedly, disruption of Nox1 as well as Nox4 significantly exacerbated cytotoxicity induced by acrolein or MVK. Compared with Nox4‐disrupted cells, Nox1‐disrupted cells were more vulnerable to acrolein and MVK at lower concentrations. Disruption of Nox1 markedly attenuated the levels of total and reduced glutathione (GSH) in H9c2 clones. Reduction in the cystine level in the culture medium to deplete intracellular GSH significantly exacerbated acrolein or MVK‐induced cytotoxicity. Nox1 disruption neither attenuated the level of glutamate–cystine antiporter protein nor the activity of glutamate–cysteine ligase, both rate‐limiting factors for GSH synthesis. On the other hand, increased expression of multidrug resistance‐associated protein 1 (MRP1), which mediates glutathione efflux, was demonstrated in Nox1‐disrupted cells. The augmented toxicity of acrolein and MVK in these cells was partially but significantly blunted in the presence of an MRP1 inhibitor, reversan. Taken together, these results show that NOX1/NADPH oxidase regulates the expression of MRP1 to maintain intracellular GSH levels in cardiomyocytes and protect against cytotoxic components of cigarette smoke extracts. A novel crosstalk between NOX1 and MRP1 was demonstrated in this study. Cytotoxicity induced by acrolein and methyl vinyl ketone, major toxic components of cigarette smoke extracts, was significantly exacerbated in H9c2 cardiomyoblasts by disruption of Nox1, one of the superoxide‐generating NADPH oxidase isoforms. Disruption of Nox1 markedly attenuated intracellular glutathione levels and was associated with increased expression of multidrug resistance‐associated protein 1 (MRP1). A novel crosstalk between NOX1 and MRP1 was demonstrated in this study. [ABSTRACT FROM AUTHOR]

Matrix metalloproteinases (MMPs) are tissue‐remodeling enzymes involved in the processing of various biological molecules. MMPs also play important roles in cancer metastasis, contributing to angiogenesis, intravasation of tumor cells, and cell migration and invasion. Accordingly, unraveling the signaling pathways controlling MMP activities could shed additional light on cancer biology. Here, we report a molecular axis, comprising the molecular adaptor hydrogen peroxide‐inducible clone‐5 (HIC‐5), NADPH oxidase 4 (NOX4), and mitochondria‐associated reactive oxygen species (mtROS), that regulates MMP9 expression and may be a target to suppress cancer metastasis. We found that this axis primarily downregulates mtROS levels which stabilize MMP9 mRNA. Specifically, HIC‐5 suppressed the expression of NOX4, the source of the mtROS, thereby decreasing mtROS levels and, consequently, destabilizing MMP9 mRNA. Interestingly, among six cancer cell lines, only EJ‐1 and MDA‐MB‐231 cells exhibited upregulation of NOX4 and MMP9 expression after shRNA‐mediated HIC‐5 knockdown. In these two cell lines, activating RAS mutations commonly occur, suggesting that the HIC‐5–mediated suppression of NOX4 depends on RAS signaling, a hypothesis that was supported experimentally by the introduction of activated RAS into mammary epithelial cells. Notably, HIC‐5 knockdown promoted lung metastasis of MDA‐MB‐231 cancer cells in mice. The tumor growth of HIC‐5–silenced MDA‐MB‐231 cells at the primary sites was comparable to that of control cells. Consistently, the invasive properties of the cells, but not their proliferation, were enhanced by the HIC‐5 knockdown in vitro. We conclude that NOX4‐mediated mtROS signaling increases MMP9 mRNA stability and affects cancer invasiveness but not tumor growth. Matrix metalloproteinases (MMPs) are a group of tissue‐remodeling enzymes that have been linked to a variety of pathophysiological processes, including cancer metastasis. Here, Motoko Shibanuma and co‐authors provide new insights into the regulation of MMP9. They show that the molecular adaptor protein HIC‐5 suppresses the activation of NADPH oxidase 4 (NOX4), leading to downregulation of mitochondrial ROS levels, which in turn destabilizes MMP9 mRNA. They further demonstrate that this regulatory axis operates specifically in cancer cells harboring oncogenic mutations in H‐ or K‐ras, potentially unveiling a new therapeutic avenue for cancer therapy based on inhibition of MMPs. [ABSTRACT FROM AUTHOR]

Estrogen-related receptor α (ERRα), one of orphan nuclear receptors with an unknown ligand, is expressed in various types of cancer. Increased ERRα levels are associated with a higher risk of recurrence and poor clinical outcome in breast cancer, suggesting that ERRα could be a negative prognostic factor. Recently, it has been suggested that vascular endothelial growth factor (VEGF) could be one of the transcriptional targets of ERRα in breast cancer. Here, we examined the expression of ERRα and the association of ERRα with VEGF in uterine cervical cancer cells and tissues.We evaluated the expression of ERRα and VEGF by immunohistologic analysis using specimens from 40 patients with invasive cervical cancer. We also evaluated the VEGF promoter activity of ERRα in cervical cancer cell lines by transfection and luciferase assay. We overexpressed or knocked down ERRα and examined VEGF expression by real-time polymerase chain reaction. Finally, cell proliferation assay was performed to examine whether ERRα affects tumor growth in cervical cancer.Immunohistologic analysis demonstrated that ERRα expression in cervical cancer tissues was higher than that in noncancerous tissues and that there was a positive association between ERRα and VEGF expression in cancer tissues (P < 0.05). We showed that ERRα stimulated the VEGF promoter activity in cervical cancer cell lines. We further showed the overexpression and knockdown of ERRα-regulated VEGF expression level by real-time polymerase chain reaction. Moreover, we showed that ERRα and VEGF knockdown by small interfering RNA or an inverse agonist of ERRα, XCT 790, could suppress cell growth compared with control cells in cervical cancer.We have provided compelling evidence that ERRα affects VEGF expression and tumor growth in cervical cancer. These results justify further investigation into the use of ERRα as a therapeutic target for patients with uterine cervical cancer. [ABSTRACT FROM AUTHOR]

The involvement of reactive oxygen species (ROS) in an augmented sensitivity to painful stimuli (hyperalgesia) during inflammation has been suggested, yet how and where ROS affect the pain signaling remain unknown. Here we report a novel role for the superoxidegenerating NADPH oxidase in the development of hyperalgesia. In mice lacking Nox1 (Nox1-/Y), a catalytic subunit of NADPH oxidase, thermal and mechanical hyperalgesia was significantly attenuated, whereas no change in nociceptive responses to heat or mechanical stimuli was observed. In dorsal root ganglia (DRG) neurons of Nox1+/Y, pretreatment with chemical mediators bradykinin, serotonin, or phorbol 12-myristate 13-acetate (PMA) augmented the capsaicin-induced calcium increase, whereas this increase was significantly attenuated in DRG neurons of Nox1-/Y. Concomitantly, PMA-induced translocation of PKCϵ was markedly perturbed in Nox1-/Y or Nox1+/Y DRG neurons treated with ROS-scavenging agents. In cells transfected with tagged PKCϵ, hydrogen peroxide induced translocation and a reduction in free sulfhydryls of full-length PKCϵ but not of the deletion mutant lacking the C1A domain. These findings indicate that NOX1/NADP Hoxidase accelerates the translocation of PKCϵ inDRGneurons, thereby enhancing the TRPV1 activity and the sensitivity to painful stimuli. [ABSTRACT FROM AUTHOR]

Abstract: Curcumin is a plant-derived diferuloylmethane compound extracted from Curcuma longa, possessing antioxidative and anticarcinogenic properties. Antioxidants and oxidative stress are known to induce the expression of certain classes of detoxification enzymes. Since the upregulation of detoxifying enzymes affects the drug metabolism and cell defense system, it is important to understand the gene regulation by such agents. In this study, we demonstrated that curcumin could induce the expression of human glutathione S-transferase P1 (GSTP1). In HepG2 cells treated with 20μM curcumin, the level of GSTP1 mRNA was significantly increased. In luciferase reporter assays, curcumin augmented the promoter activity of a reporter construct carrying 336bp upstream of the 5′-flanking region of the GSTP1 gene. Mutation analyses revealed that the region including antioxidant response element (ARE), which overlaps AP1 in sequence, was essential to the response to curcumin. While the introduction of a wild-type Nrf2 expression construct augmented the promoter activity of the GSTP1 gene, co-expression of a dominant-negative Nrf2 abolished the responsiveness to curcumin. In addition, curcumin activated the expression of the luciferase gene from a reporter construct carrying multiple ARE consensus sequences but not one with multiple AP1 sites. In a gel mobility shift assay with an oligonucleotide with GSTP1 ARE, an increase in the amount of the binding complex was observed in the nuclear extracts of curcumin-treated HepG2 cells. These results suggested that ARE is the primary sequence for the curcumin-induced transactivation of the GSTP1 gene. The induction of GSTP1 may be one of the mechanisms underlying the multiple actions of curcumin. [Copyright &y& Elsevier]