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Shannon CE, Bakewell T, Fourcaudot MJ, Ayala I, Smelter AA, Hinostroza EA, Romero G, Asmis M, Freitas Lima LC, Wallace M, Norton L. The mitochondrial pyruvate carrier regulates adipose glucose partitioning in female mice. Mol Metab 2024; 88:102005. [PMID: 39137831 PMCID: PMC11382204 DOI: 10.1016/j.molmet.2024.102005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 07/26/2024] [Accepted: 08/06/2024] [Indexed: 08/15/2024] Open
Abstract
OBJECTIVE The mitochondrial pyruvate carrier (MPC) occupies a critical node in intermediary metabolism, prompting interest in its utility as a therapeutic target for the treatment of obesity and cardiometabolic disease. Dysregulated nutrient metabolism in adipose tissue is a prominent feature of obesity pathophysiology, yet the functional role of adipose MPC has not been explored. We investigated whether the MPC shapes the adaptation of adipose tissue to dietary stress in female and male mice. METHODS The impact of pharmacological and genetic disruption of the MPC on mitochondrial pathways of triglyceride assembly (lipogenesis and glyceroneogenesis) was assessed in 3T3L1 adipocytes and murine adipose explants, combined with analyses of adipose MPC expression in metabolically compromised humans. Whole-body and adipose-specific glucose metabolism were subsequently investigated in male and female mice lacking adipocyte MPC1 (Mpc1AD-/-) and fed either standard chow, high-fat western style, or high-sucrose lipid restricted diets for 24 weeks, using a combination of radiolabeled tracers and GC/MS metabolomics. RESULTS Treatment with UK5099 or siMPC1 impaired the synthesis of lipids and glycerol-3-phosphate from pyruvate and blunted triglyceride accumulation in 3T3L1 adipocytes, whilst MPC expression in human adipose tissue was negatively correlated with indices of whole-body and adipose tissue metabolic dysfunction. Mature adipose explants from Mpc1AD-/- mice were intrinsically incapable of incorporating pyruvate into triglycerides. In vivo, MPC deletion restricted the incorporation of circulating glucose into adipose triglycerides, but only in female mice fed a zero fat diet, and this associated with sex-specific reductions in tricarboxylic acid cycle pool sizes and compensatory transcriptional changes in lipogenic and glycerol metabolism pathways. However, whole-body adiposity and metabolic health were preserved in Mpc1AD-/- mice regardless of sex, even under conditions of zero dietary fat. CONCLUSIONS These findings highlight the greater capacity for mitochondrially driven triglyceride assembly in adipose from female versus male mice and expose a reliance upon MPC-gated metabolism for glucose partitioning in female adipose under conditions of dietary lipid restriction.
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Biju K, Hernandez ET, Stallings AM, Felix-Ortiz AC, Hebbale SK, Norton L, Mader MJ, Clark RA. Resistance to high-fat diet-induced weight gain in transgenic mice overexpressing human wild-type α-synuclein: A model for metabolic dysfunction in Parkinson's disease. RESEARCH SQUARE 2024:rs.3.rs-4870881. [PMID: 39257980 PMCID: PMC11384802 DOI: 10.21203/rs.3.rs-4870881/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
Unintentional weight loss, primarily due to the loss of fat mass rather than muscle mass, is common among patients with Parkinson's disease (PD) and is associated with poor quality of life and accelerated disease progression. Since transgenic mice overexpressing human wild-type α-synuclein (α-Syn mice) are modestly leaner than control mice, and since diabetes, a metabolic disorder, is a major risk factor for PD, we reasoned that high-fat diet-induced diabetes/metabolic dysregulation in α-Syn mice may serve as a robust tool for exploring how early α-synuclein pathology contributes to metabolic dysregulation, leading to weight loss in PD. Thus, α-Syn and age-matched controls were fed a high-fat diet (HFD) chow (60% fat calories) ad libitum for four months. Compared with controls on HFD (control-HFD), α-Syn mice on HFD (α-Syn-HFD) were dramatically leaner. The resistance to gaining weight in α-Syn-HFD mice was accompanied by improved glucose tolerance, a dramatic decrease in fat mass, and an increase in energy expenditure. Despite this leaner phenotype and better glucose tolerance, the mortality was much higher in male α-Syn-HFD mice than in all controls, but was unaffected in females, suggesting protective effects of female sex hormones, as well as lower α-synuclein levels. Immunoblot analysis of insulin signaling in the olfactory bulb, the proposed initial seeding site of α-synuclein pathology, revealed a decrease of IGF-IRβ, p GSK, and p mTOR in α-Syn-HFD mice. Since GSK-3β and mTOR regulate synaptic plasticity, we assessed levels of PSD-95 and synaptophysin in the olfactory bulb. As anticipated, we observed a significant decrease in the levels of PSD-95, along with a potentially compensatory increase in synaptophysin levels. Our results show that α-Syn mice, when challenged with diet-induced diabetes/metabolic dysregulation, clearly reveal a profile of robust metabolic dysfunction, thus providing a sensitive tool for assessing the underlying mechanism of metabolic dysfunction and its impact on weight loss and disease progression in PD. We propose a role for olfactory dysfunction in PD-related unintentional weight loss and suggest that strategies aimed at increasing body weight/BMI will improve the quality of life and prognosis for people living with PD.
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Shannon CE, Bakewell T, Fourcaudot MJ, Ayala I, Romero G, Asmis M, Lima LCF, Wallace M, Norton L. Sex-dependent adipose glucose partitioning by the mitochondrial pyruvate carrier. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.11.593540. [PMID: 38798427 PMCID: PMC11118482 DOI: 10.1101/2024.05.11.593540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Objective The mitochondrial pyruvate carrier (MPC) occupies a critical node in intermediary metabolism, prompting interest in its utility as a therapeutic target for the treatment of obesity and cardiometabolic disease. Dysregulated nutrient metabolism in adipose tissue is a prominent feature of obesity pathophysiology, yet the functional role of adipose MPC has not been explored. We investigated whether the MPC shapes the adaptation of adipose tissue to dietary stress in female and male mice. Methods The impact of pharmacological and genetic disruption of the MPC on mitochondrial pathways of triglyceride assembly (lipogenesis and glyceroneogenesis) was assessed in 3T3L1 adipocytes and murine adipose explants, combined with analyses of adipose MPC expression in metabolically compromised humans. Whole-body and adipose-specific glucose metabolism were subsequently investigated in male and female mice lacking adipocyte MPC1 (Mpc1AD-/-) and fed either standard chow, high-fat western style, or high-sucrose lipid restricted diets for 24 weeks, using a combination of radiolabeled tracers and GC/MS metabolomics. Results Treatment with UK5099 or siMPC1 impaired the synthesis of lipids and glycerol-3-phosphate from pyruvate and blunted triglyceride accumulation in 3T3L1 adipocytes, whilst MPC expression in human adipose tissue was negatively correlated with indices of whole-body and adipose tissue metabolic dysfunction. Mature adipose explants from Mpc1AD-/- mice were intrinsically incapable of incorporating pyruvate into triglycerides. In vivo, MPC deletion restricted the incorporation of circulating glucose into adipose triglycerides, but only in female mice fed a zero fat diet, and this associated with sex-specific reductions in tricarboxylic acid cycle pool sizes and compensatory transcriptional changes in lipogenic and glycerol metabolism pathways. However, whole-body adiposity and metabolic health were preserved in Mpc1AD-/- mice regardless of sex, even under conditions of zero dietary fat. Conclusion These findings highlight the greater capacity for mitochondrially driven triglyceride assembly in adipose from female versus male mice and expose a reliance upon MPC-gated metabolism for glucose partitioning in female adipose under conditions of dietary lipid restriction.
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Varshney A, Manickam N, Orchard P, Tovar A, Zhang Z, Feng F, Erdos MR, Narisu N, Ventresca C, Nishino K, Rai V, Stringham HM, Jackson AU, Tamsen T, Gao C, Yang M, Koues OI, Welch JD, Burant CF, Williams LK, Jenkinson C, DeFronzo RA, Norton L, Saramies J, Lakka TA, Laakso M, Tuomilehto J, Mohlke KL, Kitzman JO, Koistinen HA, Liu J, Boehnke M, Collins FS, Scott LJ, Parker SCJ. Population-scale skeletal muscle single-nucleus multi-omic profiling reveals extensive context specific genetic regulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.15.571696. [PMID: 38168419 PMCID: PMC10760134 DOI: 10.1101/2023.12.15.571696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Skeletal muscle, the largest human organ by weight, is relevant to several polygenic metabolic traits and diseases including type 2 diabetes (T2D). Identifying genetic mechanisms underlying these traits requires pinpointing the relevant cell types, regulatory elements, target genes, and causal variants. Here, we used genetic multiplexing to generate population-scale single nucleus (sn) chromatin accessibility (snATAC-seq) and transcriptome (snRNA-seq) maps across 287 frozen human skeletal muscle biopsies representing 456,880 nuclei. We identified 13 cell types that collectively represented 983,155 ATAC summits. We integrated genetic variation to discover 6,866 expression quantitative trait loci (eQTL) and 100,928 chromatin accessibility QTL (caQTL) (5% FDR) across the five most abundant cell types, cataloging caQTL peaks that atlas-level snATAC maps often miss. We identified 1,973 eGenes colocalized with caQTL and used mediation analyses to construct causal directional maps for chromatin accessibility and gene expression. 3,378 genome-wide association study (GWAS) signals across 43 relevant traits colocalized with sn-e/caQTL, 52% in a cell-specific manner. 77% of GWAS signals colocalized with caQTL and not eQTL, highlighting the critical importance of population-scale chromatin profiling for GWAS functional studies. GWAS-caQTL colocalization showed distinct cell-specific regulatory paradigms. For example, a C2CD4A/B T2D GWAS signal colocalized with caQTL in muscle fibers and multiple chromatin loop models nominated VPS13C, a glucose uptake gene. Sequence of the caQTL peak overlapping caSNP rs7163757 showed allelic regulatory activity differences in a human myocyte cell line massively parallel reporter assay. These results illuminate the genetic regulatory architecture of human skeletal muscle at high-resolution epigenomic, transcriptomic, and cell state scales and serve as a template for population-scale multi-omic mapping in complex tissues and traits.
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Abu-Farha M, Alatrach M, Abubaker J, Al-Khairi I, Cherian P, Agyin K, Abdelgani S, Norton L, Adams J, Al-Saeed D, Al-Ozairi E, DeFronzo RA, Al-Mulla F, Abdul-Ghani M. Plasma insulin is required for the increase in plasma angiopoietin-like protein 8 in response to nutrient ingestion. Diabetes Metab Res Rev 2023; 39:e3643. [PMID: 36988137 DOI: 10.1002/dmrr.3643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 02/28/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023]
Abstract
BACKGROUND Plasma levels of angiopoietin-like protein 8 (ANGPTL8) are regulated by feeding and they increase following glucose ingestion. Because both plasma glucose and insulin increase following food ingestion, we aimed to determine whether the increase in plasma insulin and glucose or both are responsible for the increase in ANGPTL8 levels. METHODS ANGPTL8 levels were measured in 30 subjects, 14 with impaired fasting glucose (IFG), and 16 with normal fasting glucose (NFG); the subjects received 75g glucose oral Glucose tolerance test (OGTT), multistep euglycaemic hyperinsulinemic clamp and hyperglycaemic clamp with pancreatic clamp. RESULTS Subjects with IFG had significantly higher ANGPTL8 than NGT subjects during the fasting state (p < 0.05). During the OGTT, plasma ANGPTL8 concentration increased by 62% above the fasting level (p < 0.0001), and the increase above fasting in ANGPTL8 levels was similar in NFG and IFG individuals. During the multistep insulin clamp, there was a dose-dependent increase in plasma ANGPTL8 concentration. During the 2-step hyperglycaemic clamp, the rise in plasma glucose concentration failed to cause any change in the plasma ANGPTL8 concentration from baseline. CONCLUSIONS In response to nutrient ingestion, ANGPTL8 level increased due to increased plasma insulin concentration, not to the rise in plasma glucose. The incremental increase above baseline in plasma ANGLPTL8 during OGTT was comparable between people with normal glucose tolerance and IFG.
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Madaris TR, Venkatesan M, Maity S, Stein MC, Vishnu N, Venkateswaran MK, Davis JG, Ramachandran K, Uthayabalan S, Allen C, Osidele A, Stanley K, Bigham NP, Bakewell TM, Narkunan M, Le A, Karanam V, Li K, Mhapankar A, Norton L, Ross J, Aslam MI, Reeves WB, Singh BB, Caplan J, Wilson JJ, Stathopulos PB, Baur JA, Madesh M. Limiting Mrs2-dependent mitochondrial Mg 2+ uptake induces metabolic programming in prolonged dietary stress. Cell Rep 2023; 42:112155. [PMID: 36857182 PMCID: PMC10134742 DOI: 10.1016/j.celrep.2023.112155] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 10/28/2022] [Accepted: 02/08/2023] [Indexed: 03/02/2023] Open
Abstract
The most abundant cellular divalent cations, Mg2+ (mM) and Ca2+ (nM-μM), antagonistically regulate divergent metabolic pathways with several orders of magnitude affinity preference, but the physiological significance of this competition remains elusive. In mice consuming a Western diet, genetic ablation of the mitochondrial Mg2+ channel Mrs2 prevents weight gain, enhances mitochondrial activity, decreases fat accumulation in the liver, and causes prominent browning of white adipose. Mrs2 deficiency restrains citrate efflux from the mitochondria, making it unavailable to support de novo lipogenesis. As citrate is an endogenous Mg2+ chelator, this may represent an adaptive response to a perceived deficit of the cation. Transcriptional profiling of liver and white adipose reveals higher expression of genes involved in glycolysis, β-oxidation, thermogenesis, and HIF-1α-targets, in Mrs2-/- mice that are further enhanced under Western-diet-associated metabolic stress. Thus, lowering mMg2+ promotes metabolism and dampens diet-induced obesity and metabolic syndrome.
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Samms RJ, Cheng CC, Fourcaudot M, Heikkinen S, Khattab A, Adams J, Cersosimo E, Triplitt C, Puckett C, Tsintzas K, Adams AC, Abdul-Ghani MA, DeFronzo RA, Norton L. FGF21 contributes to metabolic improvements elicited by combination therapy with exenatide and pioglitazone in patients with type 2 diabetes. Am J Physiol Endocrinol Metab 2022; 323:E123-E132. [PMID: 35723225 PMCID: PMC9291413 DOI: 10.1152/ajpendo.00050.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Fibroblast growth factor 21 (FGF21) is increased acutely by carbohydrate ingestion and is elevated in patients with type 2 diabetes (T2D). However, the physiological significance of increased FGF21 in humans remains largely unknown. We examined whether FGF21 contributed to the metabolic improvements observed following treatment of patients with T2D with either triple (metformin/pioglitazone/exenatide) or conventional (metformin/insulin/glipizide) therapy for 3 yr. Forty-six patients with T2D were randomized to receive either triple or conventional therapy to maintain HbA1c < 6.5%. A 2-h 75-g oral glucose tolerance test (OGTT) was performed at baseline and following 3 years of treatment to assess glucose tolerance, insulin sensitivity, and β-cell function. Plasma total and bioactive FGF21 levels were quantitated before and during the OGTT at both visits. Patients in both treatment arms experienced significant improvements in glucose control, but insulin sensitivity and β-cell function were markedly increased after triple therapy. At baseline, FGF21 levels were regulated acutely during the OGTT in both groups. After treatment, fasting total and bioactive FGF21 levels were significantly reduced in patients receiving triple therapy, but there was a relative increase in the proportion of bioactive FGF21 compared with that observed in conventionally treated subjects. Relative to baseline studies, triple therapy treatment also significantly modified FGF21 levels in response to a glucose load. These changes in circulating FGF21 were correlated with markers of improved glucose control and insulin sensitivity. Alterations in the plasma FGF21 profile may contribute to the beneficial metabolic effects of pioglitazone and exenatide in human patients with T2D.NEW & NOTEWORTHY In patients with T2D treated with a combination of metformin/pioglitazone/exenatide (triple therapy), we observed reduced total and bioactive plasma FGF21 levels and a relative increase in the proportion of circulating bioactive FGF21 compared with that in patients treated with metformin and sequential addition of glipizide and basal insulin glargine (conventional therapy). These data suggest that FGF21 may contribute, at least in part, to the glycemic benefits observed following combination therapy in patients with T2D.
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Shannon CE, Merovci A, Fourcaudot M, Tripathy D, Abdul-Ghani M, Wang H, Han X, Norton L, DeFronzo RA. Effects of Sustained Hyperglycemia on Skeletal Muscle Lipids in Healthy Subjects. J Clin Endocrinol Metab 2022; 107:e3177-e3185. [PMID: 35552423 PMCID: PMC9282260 DOI: 10.1210/clinem/dgac306] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Indexed: 11/19/2022]
Abstract
CONTEXT Sustained increases in plasma glucose promote skeletal muscle insulin resistance independent from obesity and dyslipidemia (ie, glucotoxicity). Skeletal muscle lipids are key molecular determinants of insulin action, yet their involvement in the development of glucotoxicity is unclear. OBJECTIVE To explore the impact of mild physiologic hyperglycemia on skeletal muscle lipids. DESIGN Single group pretest-posttest. PARTICIPANTS Healthy males and females with normal glucose tolerance. INTERVENTIONS 72-hour glucose infusion raising plasma glucose by ~50 mg/dL. MAIN OUTCOME MEASURES Skeletal muscle lipids, insulin sensitivity, lipid oxidation. RESULTS Despite impairing insulin-mediated glucose disposal and suppressing fasting lipid oxidation, hyperglycemia did not alter either the content or composition of skeletal muscle triglycerides, diacylglycerides, or phospholipids. Skeletal muscle ceramides decreased after glucose infusion, likely in response to a reduction in free fatty acid concentrations. CONCLUSIONS Our results demonstrate that the major lipid pools in skeletal muscle are unperturbed by sustained increases in glucose availability and suggest that glucotoxicity and lipotoxicity drive insulin resistance through distinct mechanistic pathways.
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Norton L, Shannon C, Gastaldelli A, DeFronzo RA. Insulin: The master regulator of glucose metabolism. Metabolism 2022; 129:155142. [PMID: 35066003 DOI: 10.1016/j.metabol.2022.155142] [Citation(s) in RCA: 113] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 01/13/2022] [Accepted: 01/16/2022] [Indexed: 02/07/2023]
Abstract
Insulin is the master regulator of glucose, lipid, and protein metabolism. Following ingestion of an oral glucose load or mixed meal, the plasma glucose concentration rises, insulin secretion by the beta cells is stimulated and the hyperinsulinemia, working in concert with hyperglycemia, causes: (i) suppression of endogenous (primarily reflects hepatic) glucose production, (ii) stimulation of glucose uptake by muscle, liver, and adipocytes, (iii) inhibition of lipolysis leading to a decline in plasma FFA concentration which contributes to the suppression of hepatic glucose production and augmentation of muscle glucose uptake, and (iv) vasodilation in muscle, which contributes to enhanced muscle glucose disposal. Herein, the integrated physiologic impact of insulin to maintain normal glucose homeostasis is reviewed and the molecular basis of insulin's diverse actions in muscle, liver, adipocytes, and vasculature are discussed.
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Palavicini JP, Chavez-Velazquez A, Fourcaudot M, Tripathy D, Pan M, Norton L, DeFronzo RA, Shannon CE. The Insulin-Sensitizer Pioglitazone Remodels Adipose Tissue Phospholipids in Humans. Front Physiol 2021; 12:784391. [PMID: 34925073 PMCID: PMC8674727 DOI: 10.3389/fphys.2021.784391] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/08/2021] [Indexed: 12/11/2022] Open
Abstract
The insulin-sensitizer pioglitazone exerts its cardiometabolic benefits in type 2 diabetes (T2D) through a redistribution of body fat, from ectopic and visceral areas to subcutaneous adipose depots. Whereas excessive weight gain and lipid storage in obesity promotes insulin resistance and chronic inflammation, the expansion of subcutaneous adipose by pioglitazone is associated with a reversal of these immunometabolic deficits. The precise events driving this beneficial remodeling of adipose tissue with pioglitazone remain unclear, and whether insulin-sensitizers alter the lipidomic composition of human adipose has not previously been investigated. Using shotgun lipidomics, we explored the molecular lipid responses in subcutaneous adipose tissue following 6months of pioglitazone treatment (45mg/day) in obese humans with T2D. Despite an expected increase in body weight following pioglitazone treatment, no robust effects were observed on the composition of storage lipids (i.e., triglycerides) or the content of lipotoxic lipid species (e.g., ceramides and diacylglycerides) in adipose tissue. Instead, pioglitazone caused a selective remodeling of the glycerophospholipid pool, characterized by a decrease in lipids enriched for arachidonic acid, such as plasmanylethanolamines and phosphatidylinositols. This contributed to a greater overall saturation and shortened chain length of fatty acyl groups within cell membrane lipids, changes that are consistent with the purported induction of adipogenesis by pioglitazone. The mechanism through which pioglitazone lowered adipose tissue arachidonic acid, a major modulator of inflammatory pathways, did not involve alterations in phospholipase gene expression but was associated with a reduction in its precursor linoleic acid, an effect that was also observed in skeletal muscle samples from the same subjects. These findings offer important insights into the biological mechanisms through which pioglitazone protects the immunometabolic health of adipocytes in the face of increased lipid storage.
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Shannon CE, Ragavan M, Palavicini JP, Fourcaudot M, Bakewell TM, Valdez IA, Ayala I, Jin ES, Madesh M, Han X, Merritt ME, Norton L. Insulin resistance is mechanistically linked to hepatic mitochondrial remodeling in non-alcoholic fatty liver disease. Mol Metab 2021; 45:101154. [PMID: 33359401 PMCID: PMC7811046 DOI: 10.1016/j.molmet.2020.101154] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/18/2020] [Accepted: 12/20/2020] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE Insulin resistance and altered hepatic mitochondrial function are central features of type 2 diabetes (T2D) and non-alcoholic fatty liver disease (NAFLD), but the etiological role of these processes in disease progression remains unclear. Here we investigated the molecular links between insulin resistance, mitochondrial remodeling, and hepatic lipid accumulation. METHODS Hepatic insulin sensitivity, endogenous glucose production, and mitochondrial metabolic fluxes were determined in wild-type, obese (ob/ob) and pioglitazone-treatment obese mice using a combination of radiolabeled tracer and stable isotope NMR approaches. Mechanistic studies of pioglitazone action were performed in isolated primary hepatocytes, whilst molecular hepatic lipid species were profiled using shotgun lipidomics. RESULTS Livers from obese, insulin-resistant mice displayed augmented mitochondrial content and increased tricarboxylic acid cycle (TCA) cycle and pyruvate dehydrogenase (PDH) activities. Insulin sensitization with pioglitazone mitigated pyruvate-driven TCA cycle activity and PDH activation via both allosteric (intracellular pyruvate availability) and covalent (PDK4 and PDP2) mechanisms that were dependent on PPARγ activity in isolated primary hepatocytes. Improved mitochondrial function following pioglitazone treatment was entirely dissociated from changes in hepatic triglycerides, diacylglycerides, or fatty acids. Instead, we highlight a role for the mitochondrial phospholipid cardiolipin, which underwent pathological remodeling in livers from obese mice that was reversed by insulin sensitization. CONCLUSION Our findings identify targetable mitochondrial features of T2D and NAFLD and highlight the benefit of insulin sensitization in managing the clinical burden of obesity-associated disease.
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Lee HJ, Mariappan MM, Norton L, Bakewell T, Feliers D, Oh SB, Donati A, Rubannelsonkumar CS, Venkatachalam MA, Harris SE, Rubera I, Tauc M, Ghosh Choudhury G, Kahn CR, Sharma K, DeFronzo RA, Kasinath BS. Proximal tubular epithelial insulin receptor mediates high-fat diet-induced kidney injury. JCI Insight 2021; 6:143619. [PMID: 33400689 PMCID: PMC7934847 DOI: 10.1172/jci.insight.143619] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/29/2020] [Indexed: 01/04/2023] Open
Abstract
The role of insulin receptor (IR) activated by hyperinsulinemia in obesity-induced kidney injury is not well understood. We hypothesized that activation of kidney proximal tubule epithelial IR contributes to obesity-induced kidney injury. We administered normal-fat diet (NFD) or high-fat diet (HFD) to control and kidney proximal tubule IR–knockout (KPTIRKO) mice for 4 months. Renal cortical IR expression was decreased by 60% in male and female KPTIRKO mice. Baseline serum glucose, serum creatinine, and the ratio of urinary albumin to creatinine (ACR) were similar in KPTIRKO mice compared to those of controls. On HFD, weight gain and increase in serum cholesterol were similar in control and KPTIRKO mice; blood glucose did not change. HFD increased the following parameters in the male control mice: renal cortical contents of phosphorylated IR and Akt, matrix proteins, urinary ACR, urinary kidney injury molecule-1–to-creatinine ratio, and systolic blood pressure. Renal cortical generation of hydrogen sulfide was reduced in HFD-fed male control mice. All of these parameters were ameliorated in male KPTIRKO mice. Interestingly, female mice were resistant to HFD-induced kidney injury in both genotypes. We conclude that HFD-induced kidney injury requires renal proximal tubule IR activation in male mice.
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Morales LD, Cromack DT, Tripathy D, Fourcaudot M, Kumar S, Curran JE, Carless M, Göring HHH, Hu SL, Lopez-Alvarenga JC, Garske KM, Pajukanta P, Small KS, Glastonbury CA, Das SK, Langefeld C, Hanson RL, Hsueh WC, Norton L, Arya R, Mummidi S, Blangero J, DeFronzo RA, Duggirala R, Jenkinson CP. Further evidence supporting a potential role for ADH1B in obesity. Sci Rep 2021; 11:1932. [PMID: 33479282 PMCID: PMC7820614 DOI: 10.1038/s41598-020-80563-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/06/2020] [Indexed: 01/22/2023] Open
Abstract
Insulin is an essential hormone that regulates glucose homeostasis and metabolism. Insulin resistance (IR) arises when tissues fail to respond to insulin, and it leads to serious health problems including Type 2 Diabetes (T2D). Obesity is a major contributor to the development of IR and T2D. We previously showed that gene expression of alcohol dehydrogenase 1B (ADH1B) was inversely correlated with obesity and IR in subcutaneous adipose tissue of Mexican Americans. In the current study, a meta-analysis of the relationship between ADH1B expression and BMI in Mexican Americans, African Americans, Europeans, and Pima Indians verified that BMI was increased with decreased ADH1B expression. Using established human subcutaneous pre-adipocyte cell lines derived from lean (BMI < 30 kg m-2) or obese (BMI ≥ 30 kg m-2) donors, we found that ADH1B protein expression increased substantially during differentiation, and overexpression of ADH1B inhibited fatty acid binding protein expression. Mature adipocytes from lean donors expressed ADH1B at higher levels than obese donors. Insulin further induced ADH1B protein expression as well as enzyme activity. Knockdown of ADH1B expression decreased insulin-stimulated glucose uptake. Our findings suggest that ADH1B is involved in the proper development and metabolic activity of adipose tissues and this function is suppressed by obesity.
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Cardoso F, Paluch-Shimon S, Senkus E, Curigliano G, Aapro MS, André F, Barrios CH, Bergh J, Bhattacharyya GS, Biganzoli L, Boyle F, Cardoso MJ, Carey LA, Cortés J, El Saghir NS, Elzayat M, Eniu A, Fallowfield L, Francis PA, Gelmon K, Gligorov J, Haidinger R, Harbeck N, Hu X, Kaufman B, Kaur R, Kiely BE, Kim SB, Lin NU, Mertz SA, Neciosup S, Offersen BV, Ohno S, Pagani O, Prat A, Penault-Llorca F, Rugo HS, Sledge GW, Thomssen C, Vorobiof DA, Wiseman T, Xu B, Norton L, Costa A, Winer EP. 5th ESO-ESMO international consensus guidelines for advanced breast cancer (ABC 5). Ann Oncol 2020; 31:1623-1649. [PMID: 32979513 PMCID: PMC7510449 DOI: 10.1016/j.annonc.2020.09.010] [Citation(s) in RCA: 790] [Impact Index Per Article: 197.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 01/09/2023] Open
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Daw CC, Ramachandran K, Enslow BT, Maity S, Bursic B, Novello MJ, Rubannelsonkumar CS, Mashal AH, Ravichandran J, Bakewell TM, Wang W, Li K, Madaris TR, Shannon CE, Norton L, Kandala S, Caplan J, Srikantan S, Stathopulos PB, Reeves WB, Madesh M. Lactate Elicits ER-Mitochondrial Mg 2+ Dynamics to Integrate Cellular Metabolism. Cell 2020; 183:474-489.e17. [PMID: 33035451 PMCID: PMC7572828 DOI: 10.1016/j.cell.2020.08.049] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/15/2020] [Accepted: 08/25/2020] [Indexed: 02/06/2023]
Abstract
Mg2+ is the most abundant divalent cation in metazoans and an essential cofactor for ATP, nucleic acids, and countless metabolic enzymes. To understand how the spatio-temporal dynamics of intracellular Mg2+ (iMg2+) are integrated into cellular signaling, we implemented a comprehensive screen to discover regulators of iMg2+ dynamics. Lactate emerged as an activator of rapid release of Mg2+ from endoplasmic reticulum (ER) stores, which facilitates mitochondrial Mg2+ (mMg2+) uptake in multiple cell types. We demonstrate that this process is remarkably temperature sensitive and mediated through intracellular but not extracellular signals. The ER-mitochondrial Mg2+ dynamics is selectively stimulated by L-lactate. Further, we show that lactate-mediated mMg2+ entry is facilitated by Mrs2, and point mutations in the intermembrane space loop limits mMg2+ uptake. Intriguingly, suppression of mMg2+ surge alleviates inflammation-induced multi-organ failure. Together, these findings reveal that lactate mobilizes iMg2+ and links the mMg2+ transport machinery with major metabolic feedback circuits and mitochondrial bioenergetics.
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Moukarzel L, Ferrando L, Paula A, Brown D, Geyer F, Pareja F, Piscuoglio S, Papanastasiou A, Fusco N, Marchio C, Abu-Rustum N, Murali R, Brogi E, Wen H, Norton L, Soslow R, Vincent-Salomon A, Reis-Filho J, Weigelt B. Uterine carcinosarcomas and metaplastic breast carcinomas: Genetically related cancers? Gynecol Oncol 2020. [DOI: 10.1016/j.ygyno.2020.05.587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Mehta S, Hume E, Troxel A, Reitz C, Norton L, Lacko H, McDonald C, Freeman J, Marcus N, Volpp K, Asch D. DIGITAL TECHNOLOGIES, DATA, AND ANALYTICS. Health Serv Res 2020. [DOI: 10.1111/1475-6773.13381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Zhang L, Shannon CE, Bakewell TM, Abdul-Ghani MA, Fourcaudot M, Norton L. Regulation of ANGPTL8 in liver and adipose tissue by nutritional and hormonal signals and its effect on glucose homeostasis in mice. Am J Physiol Endocrinol Metab 2020; 318:E613-E624. [PMID: 32154742 DOI: 10.1152/ajpendo.00339.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The angiopoietin-like protein (ANGPTL) family represents a promising therapeutic target for dyslipidemia, which is a feature of obesity and type 2 diabetes (T2DM). The aim of the present study was to determine the metabolic role of ANGPTL8 and to investigate its nutritional, hormonal, and molecular regulation in key metabolic tissues. The regulation of Angptl8 gene expression by insulin and glucose was quantified using a combination of in vivo insulin clamp experiments in mice and in vitro experiments in primary and cultured hepatocytes and adipocytes. The role of AMPK signaling was examined, and the transcriptional control of Angptl8 was determined using bioinformatic and luciferase reporter approaches. The metabolism of Angptl8 knockout mice (ANGPTL8-/-) was examined following chow and high-fat diets (HFD). Insulin acutely increased Angptl8 expression in liver and adipose tissue, which involved the CCAAT/enhancer-binding protein (C/EBPβ) transcription factor. In insulin clamp experiments, glucose further enhanced Angptl8 expression in the presence of insulin in adipose tissue. The activation of AMPK signaling antagonized the effect of insulin on Angptl8 expression in hepatocytes and adipocytes. The ANGPTL8-/- mice had improved glucose tolerance and displayed reduced fed and fasted plasma triglycerides. However, there was no change in body weight or steatosis in ANGPTL8-/- mice after the HFD. These data show that ANGPTL8 plays important metabolic roles in mice that extend beyond triglyceride metabolism. The finding that insulin, glucose, and AMPK signaling regulate Angptl8 expression may provide important clues about the distinct function of ANGPTL8 in these tissues.
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Nemani N, Dong Z, Daw CC, Madaris TR, Ramachandran K, Enslow BT, Rubannelsonkumar CS, Shanmughapriya S, Mallireddigari V, Maity S, SinghMalla P, Natarajanseenivasan K, Hooper R, Shannon CE, Tourtellotte WG, Singh BB, Reeves WB, Sharma K, Norton L, Srikantan S, Soboloff J, Madesh M. Mitochondrial pyruvate and fatty acid flux modulate MICU1-dependent control of MCU activity. Sci Signal 2020; 13:eaaz6206. [PMID: 32317369 PMCID: PMC7667998 DOI: 10.1126/scisignal.aaz6206] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The tricarboxylic acid (TCA) cycle converts the end products of glycolysis and fatty acid β-oxidation into the reducing equivalents NADH and FADH2 Although mitochondrial matrix uptake of Ca2+ enhances ATP production, it remains unclear whether deprivation of mitochondrial TCA substrates alters mitochondrial Ca2+ flux. We investigated the effect of TCA cycle substrates on MCU-mediated mitochondrial matrix uptake of Ca2+, mitochondrial bioenergetics, and autophagic flux. Inhibition of glycolysis, mitochondrial pyruvate transport, or mitochondrial fatty acid transport triggered expression of the MCU gatekeeper MICU1 but not the MCU core subunit. Knockdown of mitochondrial pyruvate carrier (MPC) isoforms or expression of the dominant negative mutant MPC1R97W resulted in increased MICU1 protein abundance and inhibition of MCU-mediated mitochondrial matrix uptake of Ca2+ We also found that genetic ablation of MPC1 in hepatocytes and mouse embryonic fibroblasts resulted in reduced resting matrix Ca2+, likely because of increased MICU1 expression, but resulted in changes in mitochondrial morphology. TCA cycle substrate-dependent MICU1 expression was mediated by the transcription factor early growth response 1 (EGR1). Blocking mitochondrial pyruvate or fatty acid flux was linked to increased autophagy marker abundance. These studies reveal a mechanism that controls the MCU-mediated Ca2+ flux machinery and that depends on TCA cycle substrate availability. This mechanism generates a metabolic homeostatic circuit that protects cells from bioenergetic crisis and mitochondrial Ca2+ overload during periods of nutrient stress.
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Mallol M, Mejuto G, Bentley D, Norton L, Norton K, Yanci J. Diferencias en las respuestas fisiológicas entre triatletas masculinos y femeninos. REVISTA IBEROAMERICANA DE CIENCIAS DE LA ACTIVIDAD FÍSICA Y EL DEPORTE 2020. [DOI: 10.24310/riccafd.2020.v9i1.8300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Los objetivos de este estudio fueron analizar las diferencias entre triatletas masculinos y femeninos amateurs en el rendimiento en un test incremental máximo y en una competición simulada y describir si existe asociación entre el rendimiento en el test máximo incremental y la prueba simulada de competición. Un total de catorce triatletas recreacionales, 8 mujeres (35,0 8,1 años; 166,8 7,2 cm; 69,4 14,6 kg; 24,7 3,2 kg.m-2) y 6 hombres (47,7 14,3 años; 179,9 8,6 cm; 77,8 5,8 kg; 24,0 1,3 kg.m-2) realizaron un test incremental máximo y en una competición simulada (20 km bici y 5 km carrera a pie). A pesar de que no se observaron diferencias significativas entre el grupo masculino y femenino en el test máximo incremental, a efectos prácticos, el grupo masculino obtuvo valores mayores para VO2max, Pmax, PVT1, PVT2 y VO2VT2 (p > 0,05, ES = -0,8 a -1.9, alto). Con respecto a la competición simulada, si bien no se obtuvieron diferencias en función de sexo en los 5 km de carrera, el grupo femenino obtuvo valores significativamente inferiores para las variables velocidad (media y máxima) (p < 0,05 y p < 0,01, ES = -1,3- -4,1, alto) y potencia (media y máxima) (p < 0,01, ES = -2.4- -2.8, alto) durante los 20 km de ciclismo, así como un tiempo de ejecución del sector ciclista significativamente mayor que el grupo masculino (p < 0,01, ES = 1,6, alto). Por otro lado, un mejor rendimiento durante el test máximo incremental se asoció a un mejor rendimiento durante los 20 km de ciclismo en el grupo masculino (r = 0,848, p < 0,05), mientras que en el grupo femenino se asoció tanto a los 20 km en bici como a los 5 km corriendo (r = -0,714 a -0,822, p < 0,05). Los resultados obtenidos en el estudio ponen de manifiesto que los triatletas masculinos tienen un mejor rendimiento en un test incremental máximo y en el sector bici en una competición simulada y que la asociación entre el rendimiento en un test incremental y el rendimiento en los sectores de la prueba simulada depende del sexo.
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Srikantan S, Deng Y, Cheng ZM, Luo A, Qin Y, Gao Q, Sande-Docor GM, Tao S, Zhang X, Harper N, Shannon CE, Fourcaudot M, Li Z, Kasinath BS, Harrison S, Ahuja S, Reddick RL, Dong LQ, Abdul-Ghani M, Norton L, Aguiar RCT, Dahia PLM. The tumor suppressor TMEM127 regulates insulin sensitivity in a tissue-specific manner. Nat Commun 2019; 10:4720. [PMID: 31624249 PMCID: PMC6797792 DOI: 10.1038/s41467-019-12661-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Accepted: 09/20/2019] [Indexed: 02/03/2023] Open
Abstract
Understanding the molecular components of insulin signaling is relevant to effectively manage insulin resistance. We investigated the phenotype of the TMEM127 tumor suppressor gene deficiency in vivo. Whole-body Tmem127 knockout mice have decreased adiposity and maintain insulin sensitivity, low hepatic fat deposition and peripheral glucose clearance after a high-fat diet. Liver-specific and adipose-specific Tmem127 deletion partially overlap global Tmem127 loss: liver Tmem127 promotes hepatic gluconeogenesis and inhibits peripheral glucose uptake, while adipose Tmem127 downregulates adipogenesis and hepatic glucose production. mTORC2 is activated in TMEM127-deficient hepatocytes suggesting that it interacts with TMEM127 to control insulin sensitivity. Murine hepatic Tmem127 expression is increased in insulin-resistant states and is reversed by diet or the insulin sensitizer pioglitazone. Importantly, human liver TMEM127 expression correlates with steatohepatitis and insulin resistance. Our results suggest that besides tumor suppression activities, TMEM127 is a nutrient-sensing component of glucose/lipid homeostasis and may be a target in insulin resistance.
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McArthur H, Comen E, Bryce Y, Solomon S, Leal J, Rodine M, Abaya C, Patil S, Page D, Norton L. A randomized phase II study of peri-operative ipilimumab, nivolumab and cryoablation versus standard care in women with residual, early stage/resectable, triple negative breast cancer after standard-of-care neoadjuvant chemotherapy. Ann Oncol 2019. [DOI: 10.1093/annonc/mdz240.111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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McArthur HL, Comen EA, Solomon S, Rodine M, DiLauro Abaya C, Leal JHS, Patil S, Norton L. Abstract OT2-06-05: A randomized phase II study of peri-operative ipilimumab, nivolumab and cryoablation versus standard peri-operative care in women with residual triple negative early stage/resectable breast cancer after standard-of-care neoadjuvant chemotherapy. Cancer Res 2019. [DOI: 10.1158/1538-7445.sabcs18-ot2-06-05] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Triple negative breast cancer (TNBC) is a biologically distinct subtype with high risk of early relapse, particularly for patients who do not achieve a pathological complete response (pCR) after neoadjuvant chemotherapy (NAC), with an event free survival of < 60% at 3 years. Physical disruption of tumors with cryoablation (cryo) induces inflammation and releases antigens that can activate tumor-specific immune responses. In pre-clinical studies, the combination of cryo with checkpoint inhibition augmented tumor-specific immune responses and prevented cancer recurrence. In clinical studies, the combination of pre-operative ipilimumab (ipi)- +/- nivolumab (nivo)-mediated checkpoint blockade with cryo was safely administered in women with operable, early stage breast cancer and generated intra-tumoral and systemic immune responses (NCT01502592, NCT02833233). In this multi-center, randomized study, we evaluate the disease specific impact of peri-operative ipi, nivo and cryo versus standard care in women with residual TNBC after neoadjuvant taxane-based chemotherapy (NCT03546686).
Methods:Eligible pts are aged ≥18 years, with ER, PR and HER2 negative operable tumors ≥ 1.0 cm after neoadjuvant taxane-based chemotherapy. Approximately 160 patients will be randomized to one of two arms: standard-of-care breast surgery (control arm) or ipi/nivo/cryo followed by standard-of-care breast surgery (intervention arm). Subjects randomized to the intervention arm will undergo percutaneous, ultrasound- (or MRI-) guided cryoablation with concurrent research core biopsy 7-10 days prior to surgery, and will receive a pre-operative infusion with ipilimumab at the dose of 1mg/kg IV, and nivolumab 240mg flat dose IV (1 to 5 days prior to cryoablation). After surgery, patients will receive three additional doses of nivolumab 240mg flat dose IV Q2 weeks. Adjuvant capecitabine is recommended for all participants and will be administered per standard-of-care at the treating physician's discretion. Patients will be stratified by prior platinum administration, prior anthracycline administration, and clinical nodal status (positive versus negative) at enrollment. The primary endpoint is 3-year Event Free Survival (EFS). Secondary end points include Invasive Disease-Free Survival (IDFS), Distant Disease-Free Survival (DDFS), overall survival (OS) and safety. Exploratory correlative studies will be performed on tumor and serum to characterize the immunologic impact of the intervention and to explore predictors of efficacy and toxicity.
Citation Format: McArthur HL, Comen EA, Solomon S, Rodine M, DiLauro Abaya C, Leal JHS, Patil S, Norton L. A randomized phase II study of peri-operative ipilimumab, nivolumab and cryoablation versus standard peri-operative care in women with residual triple negative early stage/resectable breast cancer after standard-of-care neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-06-05.
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Jhaveri K, Dunphy M, Wang R, Comen E, Fornier M, Moynahan ME, Bromberg J, Ma W, Patil S, Taldone T, Rodina A, Sterlin V, Khoshi S, Lewis J, Norton L, Chiosis G, Modi S. Abstract P6-20-03: Tumor epichaperome expression using 124I PU-H71 PET (PU-PET) as a biomarker of response for PU-H71 plus nab-paclitaxel in HER2 negative (HER2-) metastatic breast cancer (MBC). Cancer Res 2019. [DOI: 10.1158/1538-7445.sabcs18-p6-20-03] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: The epichaperome is a new cancer target required for tumor survival (Joshi et al. Nature Reviews Cancer 2018). PU-H71 is a synthetic, purine scaffold epichaperome inhibitor that binds to the ATP-binding site of HSP90 specifically when HSP90 is integrated into the epichaperome (Rodina et al. Nature 2016). It has demonstrated antitumor activity in multiple xenograft models. Furthermore, sequential administration of nab-paclitaxel and PU-H71 in TNBC xenograft models augmented epichaperome levels, and in turn resulted in super-synergistic drug action with ablation of xenografted tumors and cures in mice.
Methods: This is an open label phase1b study of PU-H71 + nab-paclitaxel in pts with HER2- MBC. Pts received nab-paclitaxel at a standard dose of 260mg/m2 IV Q 3weeks. PU-H71 was administered IV 6 hrs (+/-1 hr) post nab-paclitaxel Q3weeks in 2 escalating dose levels (225mg/m2 and 300 mg/m2). All pts underwent FDG PET/CT every 6 weeks. Additionally, patients had the option to enroll on a separate diagnostic PU-PET protocol to measure epichaperome expression prior to initiating treatment on the phase 1b study, wherein they received a single dose of up to 11mci of 124I-PU-H71 IV and underwent imaging at 3-4hrs and 20-24 hrs. Primary objective was to establish the MTD/RP2D of this regimen. Secondary objectives were to assess PK of PU-H71 + nab-paclitaxel and clinical efficacy. Exploratory analysis included correlation of epichaperome expression at baseline using PU-PET with tumor response.
Results: 12 patients (5 ER+/HER2- ; 7 TNBC) were enrolled (6 at 225mg/m2 of PU-H71 and 6 at 300mg/m2). Median Age: 54 yrs (range: 37-71). Median ECOG: 0. Median lines of therapy in the metastatic setting: 6 (range 1-11) including prior taxanes in 75% of pts. Most common toxicities included diarrhea G1 58%; G2 7%, G3 7%) that was easily managed with anti-diarrheal agents, G1 fatigue (25%), G1/2 peripheral neuropathy (17%), G1 hyperglycemia (67%), G1 increases in alk phos (58%), AST (50%) and ALT (42%). Hematological toxicities included G3 leukopenia (42%), G3/4 neutropenia (67%), G3 anemia (50%) and G2 thrombocytopenia (17%). There were no DLTs. 33% (4/12) had PR, 58% (7/12) achieved SD with only 1 PD at the time of first scan; 5 pts are currently ongoing including 2 TNBC pts with PR who have been on therapy > 7 months. PK data will be presented. 8/12 patients also underwent PU-PET at baseline. A higher tumor to muscle SUV ratio at 24 hrs on PU-PET predicted response and increased PU-H71 retention on PU-PET at 24 hrs correlated with a longer duration of response.
Conclusion: The RP2D of PU-H71 was 300mg/m2 with 260mg/m2 of nab-paclitaxel administered IV every 3 weeks. The regimen is well tolerated with promising clinical activity in this heavily pre-treated cohort. Tumor epichaperome expression at baseline using PU-PET has the potential to serve as a predictive biomarker of response. A Phase 2 trial of this combination along with baseline PU-PET is currently planned.
Citation Format: Jhaveri K, Dunphy M, Wang R, Comen E, Fornier M, Moynahan ME, Bromberg J, Ma W, Patil S, Taldone T, Rodina A, Sterlin V, Khoshi S, Lewis J, Norton L, Chiosis G, Modi S. Tumor epichaperome expression using 124I PU-H71 PET (PU-PET) as a biomarker of response for PU-H71 plus nab-paclitaxel in HER2 negative (HER2-) metastatic breast cancer (MBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-20-03.
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Lee JY, Bi R, Pareja F, Geyer FC, Brown D, Wen HY, Norton L, Hicks J, Weigelt B, Reis-Filho JS. Abstract P2-01-02: Whole exome sequencing analysis of the progression from ductal carcinoma in situ to invasive ductal carcinoma. Cancer Res 2019. [DOI: 10.1158/1538-7445.sabcs18-p2-01-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Introduction: Ductal carcinoma in situ (DCIS) is a bona fide non-obligate precursor of invasive carcinoma. Single cell sequencing studies have revealed intra-lesion genetic heterogeneity in DCIS and shown that progression to invasive ductal carcinoma (IDC) may occur through different mechanisms, including the selection of a subpopulation of tumor cells, acquisition of new genetic alterations or multi-clonal invasion. Here, we sought to investigate the genetic heterogeneity of DCIS, and to document further the clonal selection process accompanying progression to IDC.
Materials and methods: Synchronous DCIS (n=16) and IDC (n=15) samples from 14 patients were microdissected separately, and DNA samples of tumor and matched normal tissues were subjected to whole-exome sequencing (WES; n=27) or massively parallel targeted sequencing of all coding regions of ≥410 cancer-related genes (n=4). Somatic genetic alterations and mutational signatures were identified using state-of-the-art bioinformatics algorithms. PyClone was employed to define the clonal architecture of each DCIS and IDC and infer the clonal shifts accompanying progression from DCIS to IDC.
Results: DCIS were found to harbor recurrent somatic mutations affecting PIK3CA (50%), GATA3 (44%), TP53 (38%), CBFB (19%), PTEN (13%), and AKT1 (13%), which are genes known to be significantly mutated in invasive breast cancers. Despite the genomic similarities between matched DCIS and IDCs, NOTCH2 and MYC were found to be amplified solely in the IDC component of two cases, and PPM1D amplification was restricted to the DCIS component of another case. The mutational signature ascribed to aging (i.e. signature 1) was the predominant mutational signature in the DCIS and IDCs analyzed. PyClone analysis revealed that all synchronous DCIS and IDC studied here were clonally related and confirmed the previous observation that DCIS displays intra-lesion genetic heterogeneity. Evidence of clonal selection in the progression from DCIS to IDC was observed in three cases, whereby a minor DCIS subclone likely constituted the substrate for the development of IDC. In one of these cases, from a patient with a BRCA1 germline pathogenic mutation, we observed a shift from the mutational signature associated with defective homologous recombination DNA repair (i.e. signature 3) to the APOBEC-related mutational signatures (i.e. signatures 2 and 13) in the progression from DCIS to IDC.
Conclusion: Intra-lesion genetic heterogeneity is a common feature in DCIS synchronously diagnosed with IDC. Our findings corroborate the notion that DCIS is a direct non-obligate precursor of IDC, and that clonal selection in the progression of DCIS to IDC may be present in a subset of cases, but is unlikely to constitute the most frequent mechanism of progression.
Citation Format: Lee JY, Bi R, Pareja F, Geyer FC, Brown D, Wen HY, Norton L, Hicks J, Weigelt B, Reis-Filho JS. Whole exome sequencing analysis of the progression from ductal carcinoma in situ to invasive ductal carcinoma [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-01-02.
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