The TET (ten–eleven translocation) family of α-ketoglutarate (α-KG)-dependent dioxygenases catalyzes the sequential oxidation of 5-methylcytosine (5mC) to 5-hydroxymethyl-cytosine (5hmC), 5-formylcytosine and 5-carboxylcytosine, leading to eventual DNA demethylation. The TET2 gene is a bona fide tumor suppressor frequently mutated in leukemia, and TET enzyme activity is inhibited in IDH1/2-mutated tumors by the oncometabolite 2-hydroxyglutarate, an antagonist of α-KG, linking 5mC oxidation to cancer development. We report here that the levels of 5hmC are dramatically reduced in human breast, liver, lung, pancreatic and prostate cancers when compared with the matched surrounding normal tissues. Associated with the 5hmC decrease is the substantial reduction of the expression of all three TET genes, revealing a possible mechanism for the reduced 5hmC in cancer cells. The decrease of 5hmC was also observed during tumor development in different genetically engineered mouse models. Together, our results identify 5hmC as a biomarker whose decrease is broadly and tightly associated with tumor development.

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The hydrogen molecule is recognized as a high potential to attenuate toxic side effects of chemotherapy and also enhance chemotherapeutic efficacy, and the development of a novel hydrogen‐generating prodrug for facile, safe, and efficient hydrogen delivery is vitally important for combined hydrogenochemotherapy but is still challenging. Here, targeting gastric cancer, a 2D magnesium boride nanosheet (MBN) is synthesized as a new type of acid‐responsive hydrogen‐releasing prodrug by an ultrasound‐assisted chemical etching route, which is used to realize hydrogenochemotherapy by combination of facile oral administration of polyvinylpyrrolidone (PVP)‐encapsulating MBN (MBN@PVP) pills with routine intravenous injection of doxorubicin (DOX). The MBN@PVP pill has high stability in normal tissues/blood environments as well as high gastric acid‐responsiveness with sustained release behavior, which matches well with its metabolism rate in the stomach in great favor of continuous and long‐term hydrogen administration. Hydrogenochemotherapy with DOX+MBN@PVP has remarkably prolonged the survival time of gastric tumor‐bearing mice by reducing the toxic side effects of chemotherapy. The mechanism for therapeutic synergy and side effect attenuation of hydrogenochemotherapy is discovered to be derived from the selectivity of hydrogen molecules in inhibiting aerobic respiration of gastric cells but activating aerobic respiration of normal cells including marrow mesenchymal stem cells and cardiac, hepatic, and splenic cells.

Collectively, our study suggests that (P)RR plays a key role in energy homeostasis and regulation of plasma lipids by integrating hepatic glucose and lipid metabolism.

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Objective: A cardinal feature of Marfan syndrome is thoracic aortic aneurysm. The contribution of the renin-angiotensin system via AT1aR (Ang II [angiotensin II] receptor type 1a) to thoracic aortic aneurysm progression remains controversial because the beneficial effects of angiotensin receptor blockers have been ascribed to off-target effects. This study used genetic and pharmacological modes of attenuating angiotensin receptor and ligand, respectively, to determine their roles on thoracic aortic aneurysm in mice with fibrillin-1 haploinsufficiency ( Fbn1 C1041G/+ ). Approach and Results: Thoracic aortic aneurysm in Fbn1 C1041G/+ mice was found to be strikingly sexual dimorphic. Males displayed aortic dilation over 12 months while aortic dilation in Fbn1 C1041G/+ females did not differ significantly from wild-type mice. To determine the role of AT1aR, Fbn1 C1041G/+ mice that were either +/+ or −/− for AT1aR were generated. AT1aR deletion reduced expansion of ascending aorta and aortic root diameter from 1 to 12 months of age in males. Medial thickening and elastin fragmentation were attenuated. An antisense oligonucleotide against angiotensinogen was administered to male Fbn1 C1041G/+ mice to determine the effects of Ang II depletion. Antisense oligonucleotide against angiotensinogen administration attenuated dilation of the ascending aorta and aortic root and reduced extracellular remodeling. Aortic transcriptome analyses identified potential targets by which inhibition of the renin-angiotensin system reduced aortic dilation in Fbn1 C1041G/+ mice. Conclusions: Deletion of AT1aR or inhibition of Ang II production exerted similar effects in attenuating pathology in the proximal thoracic aorta of male Fbn1 C1041G/+ mice. Inhibition of the renin-angiotensin system attenuated dysregulation of genes within the aorta related to pathology of Fbn1 C1041G/+ mice.

Background A single dose of small interfering RNA (siRNA) targeting liver angiotensinogen eliminates hepatic angiotensinogen and lowers blood pressure. Angiotensinogen elimination raises concerns for clinical application because an angiotensin rise is needed to maintain perfusion pressure during hypovolemia. Here, we investigated whether conventional vasopressors can raise arterial pressure after angiotensinogen depletion. Methods and Results Spontaneously hypertensive rats on a low‐salt diet were treated with siRNA (10 mg/kg fortnightly) for 4 weeks, supplemented during the final 2 weeks with fludrocortisone (6 mg/kg per day), the α‐adrenergic agonist midodrine (4 mg/kg per day), or a high‐salt diet (all groups n=6–7). Pressor responsiveness to angiotensin II and norepinephrine was assessed before and after siRNA administration. Blood pressure was measured via radiotelemetry. Depletion of liver angiotensinogen by siRNA lowered plasma angiotensinogen concentrations by 99.2±0.1% and mean arterial pressure by 19 mm Hg. siRNA‐mediated blood pressure lowering was rapidly reversed by intravenous angiotensin II or norepinephrine, or gradually reversed by fludrocortisone or high salt intake. Midodrine had no effect. Unexpectedly, fludrocortisone partially restored plasma angiotensinogen concentrations in siRNA‐treated rats, and nearly abolished plasma renin concentrations. To investigate whether this angiotensinogen originated from nonhepatic sources, fludrocortisone was administered to mice lacking hepatic angiotensinogen. Fludrocortisone did not increase angiotensinogen in these mice, implying that the rise in angiotensinogen in the siRNA‐treated rats must have depended on the liver, most likely reflecting diminished cleavage by renin. Conclusions Intact pressor responsiveness to conventional vasopressors provides pharmacological means to regulate the blood pressure–lowering effect of angiotensinogen siRNA and may support future therapeutic implementation of siRNA.

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