Metastasis formation requires active energy production and is regulated at multiple levels by mitochondrial metabolism. The hyperactive metabolism of cancer cells supports their extreme adaptability and plasticity and facilitates resistance to common anticancer therapies. In spite the potential relevance of a metastasis metabolic control therapy, so far, limited experience is available in this direction. Here, we evaluated the effect of the recently described α-ketoglutarate dehydrogenase (KGDH) inhibitor, (S)-2-[(2,6-dichlorobenzoyl) amino] succinic acid (AA6), in an orthotopic mouse model of breast cancer 4T1 and in other human breast cancer cell lines. In all conditions, AA6 altered Krebs cycle causing intracellular α-ketoglutarate (α-KG) accumulation. Consequently, the activity of the α-KG-dependent epigenetic enzymes, including the DNA demethylation ten-eleven translocation translocation hydroxylases (TETs), was increased. In mice, AA6 injection reduced metastasis formation and increased 5hmC levels in primary tumours. Moreover, in vitro and in vivo treatment with AA6 determined an α-KG accumulation paralleled by an enhanced production of nitric oxide (NO). This epigenetically remodelled metabolic environment efficiently counteracted the initiating steps of tumour invasion inhibiting the epithelial-to-mesenchymal transition (EMT). Mechanistically, AA6 treatment could be linked to upregulation of the NO-sensitive anti-metastatic miRNA 200 family and down-modulation of EMT-associated transcription factor Zeb1 and its CtBP1 cofactor. This scenario led to a decrease of the matrix metalloproteinase 3 (MMP3) and to an impairment of 4T1 aggressiveness. Overall, our data suggest that AA6 determines an α-KG-dependent epigenetic regulation of the TET–miR200–Zeb1/CtBP1–MMP3 axis providing an anti-metastatic effect in a mouse model of breast cancer-associated metastasis.

Background Cold hemodialysis (HD) prevented intra dialysis hypotension (IDH) in small, short term, randomized trials in selected patients with IDH. Whether this treatments prevents IDH and mortality in the HD population at large is unknown. Methods We investigated the relationship between dialysate temperature and the risk of IDH, i.e. nadir BP <90 mmHg, (GEE model) and all cause mortality (Cox's regression) in an incident cohort of hemodialysis patients (n = 8071). To control for confounding by bias by indication and other factors we applied instrumental variables adjusting for case mix at facility level. Results The twenty-seven % of patients in the study cohort were systematically treated with a dialysate temperature ≤ 35.5°. Over a median follow-up of 13.6 months (IQR: 5.2–26.1 months), a 0.5°C reduction of the dialysate temperature was associated with a small (-2.4%) reduction of the risk of IDH [OR: 0.976, 95% CI: 0.957–0.995, P = 0.013]. In case-mix, facility level adjusted analysis, the association became much stronger [OR: 0.67, 95% CI: 0.63–0.72, Risk reduction = 33%), P < 0.001]. In contrast, colder dialysate temperature had no effect on mortality both in the unadjusted [hazard ratio (HR) (0.5°C decrease): 1.074, 95%: 0.972–1.187, P = 0.16] and case-mix adjusted analysis at facility level [HR: 1.01, 95% CI: 0.88–1.16, P = 0.84]. Similar results were registered in additional analyses by instrumental variables applying the median dialysate temperature or the facility percentage of patients prescribed a dialysate temperature < 36°C. Further analyses restricted to patients with recurrent IDH fully confirmed these findings. Conclusions Cold HD was associated with IDH in the hemodialysis population but had no association with all-cause mortality.

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Nitric oxide (NO) synthesis is a late event during differentiation of mouse embryonic stem cells (mESC) and occurs after release from serum and leukemia inhibitory factor (LIF). Here we show that after release from pluripotency, a subpopulation of mESC, kept in the naive state by 2i/LIF, expresses endothelial nitric oxide synthase (eNOS) and endogenously synthesizes NO. This eNOS/NO-positive subpopulation (ESNO+) expresses mesendodermal markers and is more efficient in the generation of cardiovascular precursors than eNOS/NO-negative cells. Mechanistically, production of endogenous NO triggers rapid Hdac2 S-nitrosylation, which reduces association of Hdac2 with the transcriptional repression factor Zeb1, allowing mesendodermal gene expression. In conclusion, our results suggest that the interaction between Zeb1, Hdac2, and eNOS is required for early mesendodermal differentiation of naive mESC.

The epigenetic enzyme p300/CBP‐associated factor (PCAF) belongs to the GCN5‐related N‐acetyltransferase (GNAT) family together with GCN5. Although its transcriptional and post‐translational function is well characterized, little is known about its properties as regulator of cell metabolism. Here, we report the mitochondrial localization of PCAF conferred by an 85 aa mitochondrial targeting sequence (MTS) at the N‐terminal region of the protein. In mitochondria, one of the PCAF targets is the isocitrate dehydrogenase 2 (IDH2) acetylated at lysine 180. This PCAF‐regulated post‐translational modification might reduce IDH2 affinity for isocitrate as a result of a conformational shift involving predictively the tyrosine at position 179. Site‐directed mutagenesis and functional studies indicate that PCAF regulates IDH2, acting at dual level during myoblast differentiation: at a transcriptional level together with MyoD, and at a post‐translational level by direct modification of lysine acetylation in mitochondria. The latter event determines a decrease in IDH2 function with negative consequences on muscle fiber formation in C2C12 cells. Indeed, a MTS‐deprived PCAF does not localize into mitochondria, remains enriched into the nucleus, and contributes to a significant increase of muscle‐specific gene expression enhancing muscle differentiation. The role of PCAF in mitochondria is a novel finding shedding light on metabolic processes relevant to early muscle precursor differentiation.—Savoia, M., Cencioni, C., Mori, M., Atlante, S., Zaccagnini, G., Devanna, P., Di Marcotullio, L., Botta, B., Martelli, F., Zeiher, A. M., Pontecorvi, A., Farsetti, A., Spallotta, F., Gaetano, C. P300/CBP‐associated factor regulates transcription and function of isocitrate dehydrogenase 2 during muscle differentiation. FASEB J. 33, 4107–4123 (2019). http://www.fasebj.org

Arrhythmogenic cardiomyopathy (ACM) is a genetic disorder characterized by ventricular arrhythmias, contractile dysfunctions and fibro-adipose replacement of myocardium. Cardiac mesenchymal stromal cells (CMSCs) participate in disease pathogenesis by differentiating towards adipocytes and myofibroblasts. Some altered pathways in ACM are known, but many are yet to be discovered. We aimed to enrich the understanding of ACM pathogenesis by comparing epigenetic and gene expression profiles of ACM-CMSCs with healthy control (HC)-CMSCs. Methylome analysis identified 74 differentially methylated nucleotides, most of them located on the mitochondrial genome. Transcriptome analysis revealed 327 genes that were more expressed and 202 genes that were less expressed in ACM- vs. HC-CMSCs. Among these, genes implicated in mitochondrial respiration and in epithelial-to-mesenchymal transition were more expressed, and cell cycle genes were less expressed in ACM- vs. HC-CMSCs. Through enrichment and gene network analyses, we identified differentially regulated pathways, some of which never associated with ACM, including mitochondrial functioning and chromatin organization, both in line with methylome results. Functional validations confirmed that ACM-CMSCs exhibited higher amounts of active mitochondria and ROS production, a lower proliferation rate and a more pronounced epicardial-to-mesenchymal transition compared to the controls. In conclusion, ACM-CMSC-omics revealed some additional altered molecular pathways, relevant in disease pathogenesis, which may constitute novel targets for specific therapies.