Project description:Nrf2 is an important therapeutic target as activation of this pathway detoxifies harmful insults and reduces oxidative stress. However, the role of Nrf2 in cancer biology is controversial. Protection against oxidative stress and inflammation can confer a survival advantage to tumor cells, leading to a poor prognosis, and constitutive activation of Nrf2 has been detected in numerous tumors. In our study, we examined the role of two clinically relevant classes of Nrf2 activators, the synthetic triterpenoids (CDDO-Im and CDDO-Me) and dimethyl fumarate (DMF) in lung cancer. Using microarrays, we attempt to examine whether these Nrf2 activators have an effect on the same subset of Nrf2 genes.
Project description:The Keap1/Nrf2 signaling pathway is a tractable target for the pharmacological prevention of tumorigenesis. 3H-1,2-dithiole-3-thione (D3T) and 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im) are representative members of two classes of Nrf2-activating chemopreventive agents. Natural dithiolethiones have been widely used in clinical trials for cancer chemoprevention. Synthetic triterpenoids, however, have been shown to be significantly more potent Nrf2 activators and are under clinical evaluation for the treatment of chronic kidney disease. This study seeks to characterize the structure-activity relationship between D3T and CDDO-Im in mouse liver tissue. To this end we treated Wt and Nrf2-null mice with 300 umol/kg bw D3T and 3, 10, and 30 umol/kg bw CDDO-Im every other day for 5 days and evaulated global gene expression changes as a product of both treamtent and genotype using Affymetrix microarray.
Project description:Genetic versus chemoprotective activation of Nrf2 signaling: overlapping yet distinct hepatic gene expression profiles between Keap1 knockout and triterpenoid treated mice; Loss of Nrf2 signaling increases susceptibility to acute toxicity, inflammation, and carcinogenesis in mice due to the inability to mount adaptive responses. By contrast, disruption of Keap1 (a cytoplasmic modifier of Nrf2 turnover) protects against these stresses in mice; although dominant negative mutations in Keap1 have been identified recently in some human cancers. Global characterization of Nrf2 activation is important to exploit this pathway for chemoprevention in healthy, yet at-risk individuals and also to elucidate the consequences of hijacking the pathway in Keap1-mutant human cancers. This analysis also enables a global characterization of the pharmacodynamic action of CDDO-Im at a low dose that is relevant to chemoprevention. Experiment Overall Design: Liver-targeted conditional Keap1-null (CKO) mice provide a model of genetic activation of Nrf2 signaling. By coupling global gene expression analysis of CKO mice with analysis of pharmacologic activation using the synthetic oleanane triterpenoid CDDO-Im, we are able to gain insight into pathways affected by Nrf2 activation. CDDO-Im is an extremely potent activator of Nrf2 signaling. CKO mice were used to identify genes modulated by genetic activation of Nrf2 signaling. The CKO response was compared to hepatic global gene expression changes in wild-type mice treated with CDDO-Im at a maximal Nrf2 activating dose. n=3/group, male 9 week old mice were used. Mice were treated with a single dose of vehicle (10% Cremophor-EL, 10% DMSO, and PBS) or 30 umol CDDO-Im/kg body weight by gavage and sacrificed 6 h later.
Project description:Primary human and mouse T cells were treated with the multiple sclerosis drug dimethyl fumarate (DMF) or its in vivo metabolite monomethyl fumarate (MMF). Cysteines sensitive to DMF or MMF were identified using iodoacetamide alkyne enrichment.
Project description:Through a small scale metabolic-modulator screening, we have identified dimethyl fumarate (DMF), a FDA approved drug for multiple sclerosis, which suppresses neuroblastoma cell growth in vitro and in vivo. Mechanistically, DMF suppresses neuroblastoma cell growth through inducing ROS and subsequently suppressing MYCN expression.
Project description:Sickle cell disease (SCD) results from a point mutation in the β-globin gene forming hemoglobin S (HbS), which polymerizes in deoxygenated erythrocytes, triggering recurrent painful vaso-occlusive crises and chronic hemolytic anemia. Reactivation of fetal Hb (HbF) expression ameliorates these symptoms of SCD. Nuclear factor (erythroid derived-2)–like 2 (Nrf2) is a transcription factor that triggers cytoprotective and antioxidant pathways to limit oxidative damage and inflammation and increases HbF synthesis in CD34+ stem cell–derived erythroid progenitors. We investigated the ability of dimethyl fumarate (DMF), a small-molecule Nrf2 agonist, to activate γ-globin transcription and enhance HbF in tissue culture, murine and primate models. DMF recruited Nrf2 to the γ-globin promoters and the locus control region of the β-globin locus in erythroleukemia cells, elevated HbF in SCD donor–derived erythroid progenitors, and reduced hypoxia-induced sickling. Chronic DMF administration in SCD mice induced HbF and increased Nrf2-dependent genes to detoxify heme and limit inflammation. This improved hematological parameters, reduced plasma-free Hb, and attenuated inflammatory markers. Chronic DMF administration to nonanemic primates increased γ-globin mRNA in BM and HbF protein in red cells. DMF represents a potential therapy for SCD to induce HbF and augment vasoprotection and heme detoxification
Project description:Dimethyl fumarate (DMF) is an immunomodulatory treatment for multiple sclerosis (MS) that can cross the blood-brain barrier, presenting neuroprotective potential. Its mechanism of action is not fully understood and there is a need to characterize if DMF or its bioactive metabolite monomethyl fumarate (MMF) exert neuroprotective properties. The combination of adjuvant agents such as cannabidiol (CBD) could be relevant to enhance neuroprotection. The aim of this study was to compare the effects of DMF, MMF and CBD on neuroprotective and immunomodulatory pathways in neurons and microglia in vitro. We found that DMF and CBD, but not MMF, activated the Nrf2 antioxidant pathway in neurons. Similarly, only DMF and CBD, but not MMF, prevented the LPS-induced activation of the inflammatory pathway NF-kB in microglia. However, the 3 drugs inhibited the production of nitric oxide in microglia and protected neurons against apoptosis. Transcriptomically, DMF, MMF and CBD exhibited differential effects on these pathways, with DMF achieving the most pronounced changes. Our results show that DMF and MMF, despite being structurally related, present differences in their mechanisms of action that could be relevant for the achievement of neuroprotection in MS patients and the potential of CBD as an adjuvant therapy in neuroprotection.
Project description:Dimethyl fumarate (DMF) is an immunomodulatory treatment for multiple sclerosis (MS) that can cross the blood-brain barrier, presenting neuroprotective potential. Its mechanism of action is not fully understood and there is a need to characterize if DMF or its bioactive metabolite monomethyl fumarate (MMF) exert neuroprotective properties. The combination of adjuvant agents such as cannabidiol (CBD) could be relevant to enhance neuroprotection. The aim of this study was to compare the effects of DMF, MMF and CBD on neuroprotective and immunomodulatory pathways in neurons and microglia in vitro. We found that DMF and CBD, but not MMF, activated the Nrf2 antioxidant pathway in neurons. Similarly, only DMF and CBD, but not MMF, prevented the LPS-induced activation of the inflammatory pathway NF-kB in microglia. However, the 3 drugs inhibited the production of nitric oxide in microglia and protected neurons against apoptosis. Transcriptomically, DMF, MMF and CBD exhibited differential effects on these pathways, with DMF achieving the most pronounced changes. Our results show that DMF and MMF, despite being structurally related, present differences in their mechanisms of action that could be relevant for the achievement of neuroprotection in MS patients and the potential of CBD as an adjuvant therapy in neuroprotection.