Regulation of Reactive Oxygen Species and the Antioxidant Protein DJ-1 in Mastocytosis

Abstract

Neoplastic accumulation of mast cells in systemic mastocytosis (SM) associates with activating mutations in the receptor tyrosine kinase KIT. Constitutive activation of tyrosine kinase oncogenes has been linked to imbalances in oxidant/antioxidant mechanisms in other myeloproliferative disorders. However, the impact of KIT mutations on the redox status in SM and the potential therapeutic implications are not well understood. Here, we examined the regulation of reactive oxygen species (ROS) and of the antioxidant protein DJ-1 (PARK-7), which increases with cancer progression and acts to lessen oxidative damage to malignant cells, in relationship with SM severity. ROS levels were increased in both indolent (ISM) and aggressive variants of the disease (ASM). However, while DJ-1 levels were reduced in ISM with lower mast cell burden, they rose in ISM with higher mast cell burden and were significantly elevated in patients with ASM. Studies on mast cell lines revealed that activating KIT mutations induced constant ROS production and consequent DJ-1 oxidation and degradation that could explain the reduced levels of DJ-1 in the ISM population, while IL-6, a cytokine that increases with disease severity, caused a counteracting transcriptional induction of DJ-1 which would protect malignant mast cells from oxidative damage. A mouse model of mastocytosis recapitulated the biphasic changes in DJ-1 and the escalating IL-6, ROS and DJ-1 levels as mast cells accumulate, findings which were reversed with anti-IL-6 receptor blocking antibody. Our findings provide evidence of increased ROS and a biphasic regulation of the antioxidant DJ-1 in variants of SM and implicate IL-6 in DJ-1 induction and expansion of mast cells with KIT mutations. We propose consideration of IL-6 blockade as a potential adjunctive therapy in the treatment of patients with advanced mastocytosis, as it would reduce DJ-1 levels making mutation-positive mast cells vulnerable to oxidative damage.

Increased Reactive Oxygen Species and Distinct Oxidative Damage in Resveratrol-suppressed Glioblastoma Cells

“…In cancer cells, higher ROS levels result in oxidative damage in mitochondria and mitochondrial alterations that trigger the apoptosis cascade by releasing apoptotic signals. Redox regulation plays critical roles in maintaining the survival of malignant cells by reducing ROS levels [11]. Therefore, ROS levels and the efficiency of their dynamic regulation may determine the response of cancer cells to chemotherapy [12][13][14].…”

Interaction of DJ-1 with Lyn is essential for IgE-mediated stimulation of human mast cells

“…Interest in understanding the biochemical and functional properties of DJ-1 (also known as PARK7) has been fueled by the association of DJ-1 mutations with familial early onset Parkinson’s disease 27 and by altered levels in diseases such as cancer, stroke, dermatitis and mastocytosis 6, 7, 28, 29 . A well-established function of DJ-1 is to protect cells from oxidative damage partly by undergoing self-oxidation thus reducing ROS levels 30–32 , although other functions for DJ-1 independent of this feature have also been described 24, 25, 33, 34 .…”

“…ROS levels were measured with OxiSelect ™ Intracellular ROS Assay kit and DJ-1 in supernatants of stimulated cells were measured by ELISA as described 7 . Alternatively, DJ-1 and oxidized DJ-1 were detected by Western blot 7 .…”

“…We have recently demonstrated altered serum levels of DJ-1, an evolutionary conserved protein reported to protect cells against oxidative damage, in patients with atopic dermatitis patients; and a biphasic regulation in mastocytosis where DJ-1 was induced by IL-6 and implicated in the expansion of neoplastic MCs 6, 7 . Although DJ-1 is abundantly expressed in human MC lines 6, 7 , it is unknown whether DJ-1 can influence FcεRI-mediated activation of human MCs.…”

Aldh2 Attenuates Stem Cell Factor/Kit-Dependent Signaling and Activation in Mast Cells

“…The activation of mast cells causes transient increases in ROS that regulate mast cell signaling and responses [16][17][18][19]. Given the reported role of mitochondrial Aldh2 in the regulation of oxidative stress [1,3], and the associations between Aldh2, mast cells, and alcohol-induced pathologies, we sought to investigate whether Aldh2 activity plays a role in regulating mast cell behavior following FcεRI and Kit activation.…”