CPT1A Over-expression Increases Reactive Oxygen Species in the Mitochondria and Promotes Antioxidant Defenses in Prostate Cancer
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE161243 | GEO | 2020/11/12
REPOSITORIES: GEO
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Project description:Cancers reprogram their metabolism to adapt to environmental changes. In this study, we examined the consequences of altered expression of the mitochondrial enzyme carnitine palmitoyl transferase I (CPT1A) in prostate cancer (PCa) cell models. Using transcriptomic and metabolomic analyses, we compared LNCaP-C4-2 cell lines with depleted (knockdown (KD)) or increased (overexpression (OE)) CPT1A expression. Mitochondrial reactive oxygen species (ROS) were also measured. Transcriptomic analysis identified ER stress, serine biosynthesis and lipid catabolism as significantly upregulated pathways in the OE versus KD cells. On the other hand, androgen response was significantly downregulated in OE cells. These changes associated with increased acyl-carnitines, serine synthesis and glutathione precursors in OE cells. Unexpectedly, OE cells showed increased mitochondrial ROS but when challenged with fatty acids and no androgens, the Superoxide dismutase 2 (SOD2) enzyme increased in the OE cells, suggesting better antioxidant defenses with excess CPT1A expression. Public databases also showed decreased androgen response correlation with increased serine-related metabolism in advanced PCa. Lastly, worse progression free survival was observed with increased lipid catabolism and decreased androgen response. Excess CPT1A is associated with a ROS-mediated stress phenotype that can support PCa disease progression. This study provides a rationale for targeting lipid catabolic pathways for therapy in hormonal cancers.
| S-EPMC7709014 | biostudies-literature
Project description:CPT1A Over-expression Increases Reactive Oxygen Species in the Mitochondria and Promotes Antioxidant Defenses in Prostate Cancer
| PRJNA676030 | ENA
Project description:Background: Alveolar rhabdomyosarcoma (ARMS) has a high propensity to metastasize, leading to its aggressiveness and a poor survival rate among those with the disease. More than 80% of aggressive ARMSs harbor a PAX3-FKHR fusion transcription factor, which regulates cell migration and promotes metastasis, most likely by regulating the fusion protein's transcriptional targets. Therefore, identifying druggable transcription targets of PAX3-FKHR that are also downstream effectors of PAX3-FKHR-mediated cell migration and metastasis may lead to novel therapeutic approaches for treating ARMS. Methods: To identify genes whose expression is directly affected by the level of PAX3-FKHR in an ARMS cellular-context, we first developed an ARMS cell line in which PAX3-FKHR is stably down-regulated, and showed that stably downregulating PAX3-FKHR in ARMS cells significantly decreased the cells' motility. We used microarrays analysis to identify genes whose expression level decreased when PAX3-FKHR was downregulated. We used mutational analysis, promoter reporter assays, and electrophoretic mobility shift assays to determine whether PAX3-FKHR binds directly and specifically to the promoter region of the target gene. We used siRNA and pharmacologic inhibitor to downregulate the target gene of PAX3-FKHR and investigated the effect of such downregulation on cell motility, Results: We found that When PAX3-FKHR was downregulated, the expression of carnitine palmitoyltransferase 1A (CPT1A) decreased. We showed that PAX3-FKHR binds directly and specifically to a paired-domain binding-site in the CPT1A promoter region, indicating that CPT1A is a novel direct transcriptional target of PAX3-FKHR. Furthermore, downregulating CPT1Adecreased cell motility in ARMS cells, indicating that CPT1A is a downstream effector of PAX3-FKHR-mediated cell migration and metastasis. Conclusions: Taken together, we have identified CPT1A as a novel direct transcriptional target of PAX3-FKHR and revealed the novel function of CPT1A in promoting cell motility. CPT1A may represent a novel therapeutic target for the treatment of ARMS. Identification of transcription targets of PAX3-FKHR in human alveolar rhabdomyosarcoma: By stably knocking down PAX3-FKHR in human alveolar rhabdomyosarcoma cell line Rh30 and comparing the gene expression profile of the knockdown clone (KD) to the parental Rh30, transcription targets of PAX3-FKHR have been identified. Gene expression in parental Rh30 cells was compared to that in either Rh30 cells stably expressing shRNA targeting PAX3-FKHR (KD) or control non-targeting shRNA (CON), in duplicate.
2012-05-15 | E-GEOD-35862 | biostudies-arrayexpress
Project description:Cancer stem cells (CSCs) are key players in cancer progression, immune evasion, drug resistance, and recurrence, particularly in ovarian cancer. Mitochondria-associated membranes (MAMs) are dynamic structures linking mitochondria and the endoplasmic reticulum, essential for cellular processes. Whether MAMs supports CSCs and the underlying mechanisms remain largely unknown. Here, we unveil that CPT1A is highly expressed in ovarian cancer stem cells (OCSCs) and is essential for stemness maintenance. CPT1A facilitates stemness maintenance by regulating lipid desaturation in ovarian cancer. Further studies confirmed that CPT1A enhances SREBP1 cleavage and nuclear translocation, thereby upregulating SCD1 expression and promoting lipid desaturation in OCSCs. Furthermore, MAMs are found to be critical for SREBP1 activation. Mechanistic studies have shown that CPT1A promotes mitochondrial fission factor (MFF) succinylation (succK-MFF) through its lysine succinyltransferase (LSTase) activity, with succK-MFF being crucial for MAMs formation and SREBP1 activation. Additionally, inhibiting the LSTase activity of CPT1A with Glyburide reduced OCSCs' stemness and enhanced cisplatin's anti-tumor effects against ovarian cancer both in vitro and in vivo. Together, our studies reveal the importance of CPT1A's LSTase activity in MAMs formation and OCSCs' stemness maintenance, providing potential targets and therapeutic strategies for ovarian cancer treatment.
2024-08-26 | GSE273383 | GEO
Project description:Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is a nuclear and mitochondrial protein that in nuclei and in vitro repairs blocked 3' DNA termini such as 3' phosphotyrosine conjugates resulting from stalling of topoisomerase I-DNA intermediates. Its mutation also causes spinocerebellar ataxia with axonal neuropathy type 1 (SCAN1). Because Tdp1 colocalizes with mitochondria following oxidative stress, we hypothesized that Tdp1 repairs mitochondrial DNA (mtDNA) and that mtDNA damage mediates entry of Tdp1 into the mitochondria. To test this, we used S. cerevisiae mutants, cultured mouse and human cells, and a Tdp1 knockout mouse. H2O2- and rotenone-induced cellular and intramitochondrial reactive oxygen species (ROS) activated oxidant-responsive kinases P38 and ERK1, and the translocation of Tdp1 from the nucleus to the mitochondria via the TIM/TOM complex. This translocation occurred independently of mtDNA. Within the mitochondria, Tdp1 interacted with Ligase III and reduced mtDNA mutations. Tdp1-deficient tissues had impaired mitochondrial respiration and decreased viability. These observations suggest that Tdp1 maintains mtDNA integrity and support the hypothesis that mitochondrial dysfunction contributes to the pathology of SCAN1.
| S-EPMC5844879 | biostudies-literature
Project description:Maize shoot development progresses from non-pigmented meristematic cells at the base of the leaf to expanded and non-dividing green cells of the leaf blade. This transition is accompanied by the conversion of promitochondria and proplastids to their mature forms and massive fragmentation of both mitochondrial DNA (mtDNA) and plastid DNA (ptDNA), collectively termed organellar DNA (orgDNA). We measured developmental changes in reactive oxygen species (ROS), which at high concentrations can lead to oxidative stress and DNA damage, as well as antioxidant agents and oxidative damage in orgDNA. Our plants were grown under normal, non-stressful conditions. Nonetheless, we found more oxidative damage in orgDNA from leaf than stalk tissues and higher levels of hydrogen peroxide, superoxide, and superoxide dismutase in leaf than stalk tissues and in light-grown compared to dark-grown leaves. In both mitochondria and plastids, activities of the antioxidant enzyme peroxidase were higher in stalk than in leaves and in dark-grown than light-grown leaves. In protoplasts, the amount of the small-molecule antioxidants, glutathione and ascorbic acid, and catalase activity were also higher in the stalk than in leaf tissue. The data suggest that the degree of oxidative stress in the organelles is lower in stalk than leaf and lower in dark than light growth conditions. We speculate that the damaged/fragmented orgDNA in leaves (but not the basal meristem) results from ROS signaling to the nucleus to stop delivering DNA repair proteins to mature organelles producing large amounts of ROS.
| S-EPMC7248337 | biostudies-literature
Project description:The production of ROS (reactive oxygen species) by mammalian mitochondria is important because it underlies oxidative damage in many pathologies and contributes to retrograde redox signalling from the organelle to the cytosol and nucleus. Superoxide (O2(*-)) is the proximal mitochondrial ROS, and in the present review I outline the principles that govern O2(*-) production within the matrix of mammalian mitochondria. The flux of O2(*-) is related to the concentration of potential electron donors, the local concentration of O2 and the second-order rate constants for the reactions between them. Two modes of operation by isolated mitochondria result in significant O2(*-) production, predominantly from complex I: (i) when the mitochondria are not making ATP and consequently have a high Deltap (protonmotive force) and a reduced CoQ (coenzyme Q) pool; and (ii) when there is a high NADH/NAD+ ratio in the mitochondrial matrix. For mitochondria that are actively making ATP, and consequently have a lower Deltap and NADH/NAD+ ratio, the extent of O2(*-) production is far lower. The generation of O2(*-) within the mitochondrial matrix depends critically on Deltap, the NADH/NAD+ and CoQH2/CoQ ratios and the local O2 concentration, which are all highly variable and difficult to measure in vivo. Consequently, it is not possible to estimate O2(*-) generation by mitochondria in vivo from O2(*-)-production rates by isolated mitochondria, and such extrapolations in the literature are misleading. Even so, the description outlined here facilitates the understanding of factors that favour mitochondrial ROS production. There is a clear need to develop better methods to measure mitochondrial O2(*-) and H2O2 formation in vivo, as uncertainty about these values hampers studies on the role of mitochondrial ROS in pathological oxidative damage and redox signalling.
| S-EPMC2605959 | biostudies-literature
Project description:To compare the transcriptional profile in aged kidneys lacking tubular Cpt1a with floxed littermate controls.
2024-03-01 | GSE205497 | GEO
Project description:To compare the transcriptional profile in renal tubules conditional deletion of Cpt1a, to floxed littermate controls.
2024-03-01 | GSE246150 | GEO
Project description:Mitochondrial reactive oxygen species (ROS) have emerged as an important mechanism of disease and redox signaling in the cardiovascular system. Under basal or pathological conditions, electron leakage for ROS production is primarily mediated by the electron transport chain and the proton motive force consisting of a membrane potential (ΔΨ) and a proton gradient (ΔpH). Several factors controlling ROS production in the mitochondria include flavin mononucleotide and flavin mononucleotide-binding domain of complex I, ubisemiquinone and quinone-binding domain of complex I, flavin adenine nucleotide-binding moiety and quinone-binding pocket of complex II, and unstable semiquinone mediated by the Q cycle of complex III. In mitochondrial complex I, specific cysteinyl redox domains modulate ROS production from the flavin mononucleotide moiety and iron-sulfur clusters. In the cardiovascular system, mitochondrial ROS have been linked to mediating the physiological effects of metabolic dilation and preconditioning-like mitochondrial ATP-sensitive potassium channel activation. Furthermore, oxidative post-translational modification by glutathione in complex I and complex II has been shown to affect enzymatic catalysis, protein-protein interactions, and enzyme-mediated ROS production. Conditions associated with oxidative or nitrosative stress, such as myocardial ischemia and reperfusion, increase mitochondrial ROS production via oxidative injury of complexes I and II and superoxide anion radical-induced hydroxyl radical production by aconitase. Further insight into cellular mechanisms by which specific redox post-translational modifications regulate ROS production in the mitochondria will enrich our understanding of redox signal transduction and identify new therapeutic targets for cardiovascular diseases in which oxidative stress perturbs normal redox signaling.
| S-EPMC4118662 | biostudies-literature