Similar Datasets
Project description:Tumor cell metabolic plasticity is essential for tumor progression and therapeutic response, but the mechanism for regulation of metabolic plasticity remain poorly explored. Here, we identify PROX1 as an essential determinant for tumor metabolic plasticity. Notably, PROX1 is significantly reduced in response to metabolic stress or AMPK activation and is elevated in LKB1-deficient tumors in mice and human. Furthermore, the Ser79 phosphorylation of PROX1 by AMPK significantly alters its protein activity and allows a rapid recruitment of CUL4-DDB1 E3 ubiquitin ligase to promote PROX1 degradation under glucose starvation, a critical event that drives BCAA metabolism rewiring to suppress mTOR signaling. Importantly, PROX1 loss or Ser79 phosphorylation in HCC shows therapeutic resistance to metformin. Consistently, genetic ablation of PROX1 renders LKB1‐deficient KRAS-driven lung cancer resistant to phenformin treatment. Conversely, mice harboring non-phosphorylated PROX1 mutant or LKB1 mutant exhibit high PROX1 stabilization, promoting liver and lung cancer progression. Clinically, AMPK-PROX1 axis in human cancers is important for patient clinical outcomes. Collectively, our results demonstrate that the deficiency in the LKB1-AMPK axis in cancers reactivates PROX1 to sustain intracellular BCAA pools, resulting in enhanced mTOR signaling, and facilitating tumorigenesis and aggressiveness.
2022-09-27 | GSE214193 | GEO
Project description:Tumor cell metabolic plasticity is essential for tumor progression and therapeutic response, but the mechanism for regulation of metabolic plasticity remain poorly explored. Here, we identify PROX1 as an essential determinant for tumor metabolic plasticity. Notably, PROX1 is significantly reduced in response to metabolic stress or AMPK activation and is elevated in LKB1-deficient tumors in mice and human. Furthermore, the Ser79 phosphorylation of PROX1 by AMPK significantly alters its protein activity and allows a rapid recruitment of CUL4-DDB1 E3 ubiquitin ligase to promote PROX1 degradation under glucose starvation, a critical event that drives BCAA metabolism rewiring to suppress mTOR signaling. Importantly, PROX1 loss or Ser79 phosphorylation in HCC shows therapeutic resistance to metformin. Consistently, genetic ablation of PROX1 renders LKB1‐deficient KRAS-driven lung cancer resistant to phenformin treatment. Conversely, mice harboring non-phosphorylated PROX1 mutant or LKB1 mutant exhibit high PROX1 stabilization, promoting liver and lung cancer progression. Clinically, AMPK-PROX1 axis in human cancers is important for patient clinical outcomes. Collectively, our results demonstrate that the deficiency in the LKB1-AMPK axis in cancers reactivates PROX1 to sustain intracellular BCAA pools, resulting in enhanced mTOR signaling, and facilitating tumorigenesis and aggressiveness.
2022-09-27 | GSE214192 | GEO
Project description:PROX1 Orchestrates Tumor Metabolic Plasticity by Integrating LKB1-AMPK Signaling with BCAA Catabolism
| PRJNA884334 | ENA
Project description:PROX1 Orchestrates Tumor Metabolic Plasticity by Integrating LKB1-AMPK Signaling with BCAA Catabolism (RNA-Seq)
| PRJNA884342 | ENA
Project description:PROX1 Orchestrates Tumor Metabolic Plasticity by Integrating LKB1-AMPK Signaling with BCAA Catabolism (ATAC-Seq)
| PRJNA884343 | ENA
Project description:Dendritic cells (DCs) play a pivotal role in priming adaptive immunity. However, the involvement of DCs in controlling excessive and deleterious T cell responses remains poorly defined. Moreover, the metabolic dependence and regulation of DC function are unclear. Here we show that LKB1 signaling in DCs functions as a brake to restrain excessive tumor-promoting regulatory T cell (Treg) and Th17 cell responses, thereby promoting protective anti-tumor immunity and maintaining proper immune homeostasis. LKB1 deficiency results in dysregulated metabolism and mTOR activation of DCs. Loss of LKB1 also leads to aberrant DC maturation and production of cytokines and immunoregulatory molecules. Blocking mTOR signaling in LKB1-deficient DCs partially rectifies the abnormal phenotypes of DC activation and Treg expansion, whereas uncontrolled Th17 responses depend upon IL-6-STAT3 signaling. By coordinating metabolic and immune quiescence of DCs, LKB1 acts as a crucial signaling hub in DCs to enforce protective anti-tumor immunity and normal immune homeostasis.
| S-EPMC6796952 | biostudies-literature
Project description:Circulating branched-chain amino acid (BCAA) levels are elevated in obesity/diabetes and are a sensitive predictor for type 2 diabetes. Here we show in rats that insulin dose-dependently lowers plasma BCAA levels through induction of hepatic protein expression and activity of branched-chain ?-keto acid dehydrogenase (BCKDH), the rate-limiting enzyme in the BCAA degradation pathway. Selective induction of hypothalamic insulin signaling in rats and genetic modulation of brain insulin receptors in mice demonstrate that brain insulin signaling is a major regulator of BCAA metabolism by inducing hepatic BCKDH. Short-term overfeeding impairs the ability of brain insulin to lower BCAAs in rats. High-fat feeding in nonhuman primates and obesity and/or diabetes in humans is associated with reduced BCKDH protein in liver. These findings support the concept that decreased hepatic BCKDH is a major cause of increased plasma BCAAs and that hypothalamic insulin resistance may account for impaired BCAA metabolism in obesity and diabetes.
| S-EPMC4254305 | biostudies-literature
Project description:To sustain tumor growth, cancer cells must be able to adapt to fluctuations in energy availability. We have identified a single microRNA that controls glioma cell proliferation, migration, and responsiveness to glucose deprivation. Abundant glucose allows relatively high miR-451 expression, promoting cell growth. In low glucose, miR-451 levels decrease, slowing proliferation but enhancing migration and survival. This allows cells to survive metabolic stress and seek out favorable growth conditions. In glioblastoma patients, elevated miR-451 is associated with shorter survival. The effects of miR-451 are mediated by LKB1, which it represses through targeting its binding partner, CAB39 (MO25 alpha). Overexpression of miR-451 sensitized cells to glucose deprivation, suggesting that its downregulation is necessary for robust activation of LKB1 in response to metabolic stress. Thus, miR-451 is a regulator of the LKB1/AMPK pathway, and this may represent a fundamental mechanism that contributes to cellular adaptation in response to altered energy availability.
| S-EPMC3125113 | biostudies-literature
Project description:Metabolic modulation is a promising therapeutic approach to prevent adverse remodeling of the ischemic heart. Because little is known about the involvement of long non-coding RNAs (lncRNAs) in regulating cardiac metabolism, we used unbiased transcriptome profiling in a mouse model of myocardial infarction (MI). We identified a novel cardiomyocyte-enriched lncRNA, called LncHrt, which regulates metabolism and the pathophysiological processes that lead to heart failure. AAV-based LncHrt overexpression protects the heart from MI as demonstrated by improved contractile function, preserved metabolic homeostasis, and attenuated maladaptive remodeling responses. RNA-pull down followed by mass spectrometry and RNA immunoprecipitation (RIP) identified SIRT2 as a LncHrt-interacting protein involved in cardiac metabolic regulation. Mechanistically, we established that LncHrt interacts with SIRT2 to preserve SIRT2 deacetylase activity by interfering with the CDK5 and SIRT2 interaction. This increases downstream LKB1-AMPK kinase signaling, which ameliorates functional and metabolic deficits. Importantly, we found the expression of the human homolog of mouse LncHrt was decreased in patients with dilated cardiomyopathy. Together, these studies identify LncHrt as a cardiac metabolic regulator that plays an essential role in preserving heart function by regulating downstream metabolic signaling pathways. Consequently, LncHrt is a potentially novel RNA-based therapeutic target for ischemic heart disease.
| S-EPMC8357683 | biostudies-literature
Project description:Recent studies implicate a strong association between elevated plasma branched-chain amino acids (BCAAs) and insulin resistance (IR). However, a causal relationship and whether interrupted BCAA homeostasis can serve as a therapeutic target for diabetes remain to be established experimentally. In this study, unbiased integrative pathway analyses identified a unique genetic link between obesity-associated IR and BCAA catabolic gene expression at the pathway level in human and mouse populations. In genetically obese (ob/ob) mice, rate-limiting branched-chain α-keto acid (BCKA) dehydrogenase deficiency (i.e., BCAA and BCKA accumulation), a metabolic feature, accompanied the systemic suppression of BCAA catabolic genes. Restoring BCAA catabolic flux with a pharmacological inhibitor of BCKA dehydrogenase kinase (BCKDK) ( a suppressor of BCKA dehydrogenase) reduced the abundance of BCAA and BCKA and markedly attenuated IR in ob/ob mice. Similar outcomes were achieved by reducing protein (and thus BCAA) intake, whereas increasing BCAA intake did the opposite; this corroborates the pathogenic roles of BCAAs and BCKAs in IR in ob/ob mice. Like BCAAs, BCKAs also suppressed insulin signaling via activation of mammalian target of rapamycin complex 1. Finally, the small-molecule BCKDK inhibitor significantly attenuated IR in high-fat diet-induced obese mice. Collectively, these data demonstrate a pivotal causal role of a BCAA catabolic defect and elevated abundance of BCAAs and BCKAs in obesity-associated IR and provide proof-of-concept evidence for the therapeutic validity of manipulating BCAA metabolism for treating diabetes.
| S-EPMC6702639 | biostudies-literature