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1.
Nat Commun ; 15(1): 6869, 2024 Aug 11.
Article in English | MEDLINE | ID: mdl-39127676

ABSTRACT

In C. elegans mechanisms by which peripheral organs relay internal state information to the nervous system remain unknown, although strong evidence suggests that such signals do exist. Here we report the discovery of a peptide of the ancestral insulin superfamily called INS-7 that functions as an enteroendocrine peptide and is secreted from specialized cells of the intestine. INS-7 secretion is stimulated by food withdrawal, increases during fasting and acts as a bona fide gut-to-brain peptide that attenuates the release of a neuropeptide that drives fat loss in the periphery. Thus, INS-7 functions as a homeostatic signal from the intestine that gates the neuronal drive to stimulate fat loss during food shortage. Mechanistically, INS-7 functions as an antagonist at the canonical DAF-2 receptor and functions via FOXO and AMPK signaling in ASI neurons. Phylogenetic analysis suggests that INS-7 bears greater resemblance to members of the broad insulin/relaxin superfamily than to conventional mammalian insulin and IGF peptides. The discovery of an endogenous insulin antagonist secreted by specialized intestinal cells with enteroendocrine functions suggests unexpected and important properties of the intestine and its role in directing neuronal functions.


Subject(s)
Caenorhabditis elegans Proteins , Caenorhabditis elegans , Homeostasis , Insulin , Neurons , Animals , Neurons/metabolism , Neurons/drug effects , Insulin/metabolism , Caenorhabditis elegans/metabolism , Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans Proteins/genetics , Receptor, Insulin/metabolism , Receptor, Insulin/antagonists & inhibitors , Signal Transduction/drug effects , Brain/metabolism , Brain/drug effects , Neuropeptides/metabolism , Forkhead Transcription Factors/metabolism , Forkhead Transcription Factors/genetics , Intestines , Phylogeny , Fasting , Intestinal Mucosa/metabolism
2.
bioRxiv ; 2024 Jan 05.
Article in English | MEDLINE | ID: mdl-38903082

ABSTRACT

BACKGROUND AND AIMS: In vivo induction of alcoholic chronic pancreatitis (ACP) causes significant acinar damage, increased fibroinflammatory response, and heightened activation of cyclic response element binding protein 1 (CREB) when compared with alcohol (A) or chronic pancreatitis (CP) mediated pancreatic damage. However, the study elucidating the cooperative interaction between CREB and the oncogenic Kras G12D/+ (Kras*) in promoting pancreatic cancer progression with ACP remains unexplored. METHODS: Experimental ACP induction was established in multiple mouse models, followed by euthanization of the animals at various time intervals during the recovery periods. Tumor latency was determined in these mice cohorts. Here, we established CREB deletion (Creb fl/fl ) in Ptf1a CreERTM/+ ;LSL-Kras G12D+/-(KC) genetic mouse models (KCC-/-). Western blot, phosphokinase array, and qPCR were used to analyze the pancreata of Ptf1a CreERTM+/-, KC and KCC -/- mice. The pancreata of ACP-induced KC mice were subjected to single-cell RNA sequencing (scRNAseq). Further studies involved conducting lineage tracing and acinar cell explant cultures. RESULTS: ACP induction in KC mice had detrimental effects on the pancreatic damage repair mechanism. The persistent existence of acinar cell-derived ductal lesions demonstrated a prolonged state of hyperactivated CREB. Persistent CREB activation leads to acinar cell reprogramming and increased pro-fibrotic inflammation in KC mice. Acinar-specific Creb ablation reduced advanced PanINs lesions, hindered tumor progression, and restored acinar cell function in ACP-induced mouse models. CONCLUSIONS: Our findings demonstrate that CREB cooperates with Kras* to perpetuate an irreversible ADM and PanIN formation. Moreover, CREB sustains oncogenic activity to promote the progression of premalignant lesions toward cancer in the presence of ACP.

3.
Nat Aging ; 4(1): 10-11, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38195726
4.
bioRxiv ; 2023 Oct 23.
Article in English | MEDLINE | ID: mdl-37961386

ABSTRACT

In C. elegans mechanisms by which peripheral organs relay internal state information to the nervous system remain unknown, although strong evidence suggests that such signals do exist. Here we report the discovery of a peptide of the ancestral insulin superfamily called INS-7 that functions as an enteroendocrine peptide and is secreted from specialized cells of the intestine. INS-7 secretion increases during fasting, and acts as a bona fide gut-to-brain homeostatic signal that attenuates neuronally induced fat loss during food shortage. INS-7 functions as an antagonist at the canonical DAF-2 receptor in the nervous system, and phylogenetic analysis suggests that INS-7 bears greater resemblance to members of the broad insulin/relaxin superfamily than to conventional mammalian insulin and IGF peptides. The discovery of an endogenous insulin antagonist secreted by specialized intestinal cell with enteroendocrine functions suggests that much remains to be learned about the intestine and its role in directing neuronal functions.

5.
Cancer Res Commun ; 3(7): 1224-1236, 2023 07.
Article in English | MEDLINE | ID: mdl-37448553

ABSTRACT

Pancreatic ductal adenocarcinoma (PDAC) is a significant contributor to cancer-related morbidity and mortality, and it is known for its resistance to conventional treatment regimens, including chemotherapy and immune checkpoint blockade (ICB)-based therapies. We have previously shown that Urolithin A (Uro A), a gut microbial metabolite derived from pomegranates, can target and inhibit KRAS-dependent PI3K/AKT/mTOR signaling pathways to overcome therapeutic resistance and improve survival in PDAC. However, the effect of Uro A on the tumor immune microenvironment and its ability to enhance ICB efficacy has not been explored. This study demonstrates that Uro A treatment reduces stromal fibrosis and reinvigorates the adaptive T-cell immune response to overcome resistance to PD-1 blockade in a genetically engineered mouse model (GEMM) of PDAC. Flow cytometric-based analysis of Uro A-treated mouse tumors revealed a significant attenuation of immunosuppressive tumor-associated M2-like macrophages with a concurrent increase in the infiltration of CD4+ and CD8+ T cells with memory-like phenotype along with reduced expression of the exhaustion-associated protein, PD-1. Importantly, the combination of Uro A treatment with anti-PD-1 immunotherapy promoted enhancement of the antitumor response with increased infiltration of CD4+ Th1 cells, ultimately resulting in a remarkable improvement in overall survival in GEMM of PDAC. Overall, our findings provide preclinical evidence for the potential of Uro A as a novel therapeutic agent to increase sensitivity to immunotherapy in PDAC and warrant further mechanistic exploration in preclinical and clinical studies. Significance: Immunotherapeutic agents are ineffective against pancreatic cancer, mainly due to the immunosuppressive tumor microenvironment and stromal desmoplasia. Our current study demonstrates the therapeutic utility of a novel gut microbial metabolite, Uro A, to remodel the stromal-immune microenvironment and improve overall survival with anti-PD-1 therapy in pancreatic cancer.


Subject(s)
Carcinoma, Pancreatic Ductal , Pancreatic Neoplasms , Mice , Animals , Immune Checkpoint Inhibitors/pharmacology , CD8-Positive T-Lymphocytes/metabolism , Phosphatidylinositol 3-Kinases/pharmacology , Pancreatic Neoplasms/drug therapy , Carcinoma, Pancreatic Ductal/drug therapy , Tumor Microenvironment
6.
Am J Physiol Gastrointest Liver Physiol ; 323(4): G375-G386, 2022 Oct 01.
Article in English | MEDLINE | ID: mdl-36098401

ABSTRACT

Heavy alcohol consumption is the dominant risk factor for chronic pancreatitis (CP); however, treatment and prevention strategies for alcoholic chronic pancreatitis (ACP) remains limited. The present study demonstrates that ACP induction in C57BL/6 mice causes significant acinar cell injury, pancreatic stellate cell (PSC) activation, exocrine function insufficiency, and an increased fibroinflammatory response when compared with alcohol or CP alone. Although the withdrawal of alcohol during ACP recovery led to reversion of pancreatic damage, continued alcohol consumption with established ACP perpetuated pancreatic injury. In addition, phosphokinase array and Western blot analysis of ACP-induced mice pancreata revealed activation of the phosphatidylinositol 3 kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) and cyclic AMP response element binding protein (CREB) signaling pathways possibly orchestrating the fibroinflammatory program of ACP pathogenesis. Mice treated with urolithin A (Uro A, a gut-derived microbial metabolite) in the setting of ACP with continued alcohol intake (during the recovery period) showed suppression of AKT and P70S6K activation, and acinar damage was significantly reduced with a parallel reduction in pancreas-infiltrating macrophages and proinflammatory cytokine accumulation. These results collectively provide mechanistic insight into the impact of Uro A on attenuation of ACP severity through suppression of PI3K/AKT/mTOR signaling pathways and can be a useful therapeutic approach in patients with ACP with continuous alcohol intake.NEW & NOTEWORTHY Our novel findings presented here demonstrate the utility of Uro A as an effective therapeutic agent in attenuating alcoholic chronic pancreatitis (ACP) severity with alcohol continuation after established disease, through suppression of the PI3K/AKT/mTOR signaling pathway.


Subject(s)
Pancreatitis, Alcoholic , Proto-Oncogene Proteins c-akt , Mice , Animals , Proto-Oncogene Proteins c-akt/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Ribosomal Protein S6 Kinases, 70-kDa/metabolism , Ribosomal Protein S6 Kinases, 70-kDa/pharmacology , Cyclic AMP Response Element-Binding Protein/metabolism , Mice, Inbred C57BL , TOR Serine-Threonine Kinases/metabolism , Signal Transduction , Pancreatitis, Alcoholic/pathology , Sirolimus/pharmacology , Cytokines/pharmacology , Alcohol Drinking , Mammals/metabolism
7.
Mol Cancer Ther ; 20(11): 2280-2290, 2021 11.
Article in English | MEDLINE | ID: mdl-34518296

ABSTRACT

A hallmark of pancreatic ductal adenocarcinoma (PDAC) is the presence of a dense, desmoplastic stroma and the consequent altered interactions between cancer cells and their surrounding tumor microenvironment (TME) that promote disease progression, metastasis, and chemoresistance. We have previously shown that IL6 secreted from pancreatic stellate cells (PSC) stimulates the activation of STAT3 signaling in tumor cells, an established mechanism of therapeutic resistance in PDAC. We have now identified the tumor cell-derived cytokine IL1α as an upstream mediator of IL6 release from PSCs that is involved in STAT3 activation within the TME. Herein, we show that IL1α is overexpressed in both murine and human PDAC tumors and engages with its cognate receptor IL1R1, which is strongly expressed on stromal cells. Further, we show that IL1R1 inhibition using anakinra (recombinant IL1 receptor antagonist) significantly reduces stromal-derived IL6, thereby suppressing IL6-dependent STAT3 activation in human PDAC cell lines. Anakinra treatment results in significant reduction in IL6 and activated STAT3 levels in pancreatic tumors from Ptf1aCre/+;LSL-KrasG12D/+; Tgfbr2flox/flox (PKT) mice. Additionally, the combination of anakinra with cytotoxic chemotherapy significantly extends overall survival compared with vehicle treatment or anakinra monotherapy in this aggressive genetic mouse model of PDAC. These data highlight the importance of IL1 in mediating tumor-stromal IL6/STAT3 cross-talk in the TME and provide a preclinical rationale for targeting IL1 signaling as a therapeutic strategy in PDAC.


Subject(s)
Interleukin-6/metabolism , Pancreatic Neoplasms/genetics , Receptors, Interleukin-1/antagonists & inhibitors , Animals , Humans , Mice , Pancreatic Neoplasms/pathology , Signal Transduction
8.
Mol Cancer Ther ; 20(7): 1246-1256, 2021 07.
Article in English | MEDLINE | ID: mdl-34001634

ABSTRACT

Activating KRAS mutations, a defining feature of pancreatic ductal adenocarcinoma (PDAC), promote tumor growth in part through the activation of cyclin-dependent kinases (CDK) that induce cell-cycle progression. p16INK4a (p16), encoded by the gene CDKN2A, is a potent inhibitor of CDK4/6 and serves as a critical checkpoint of cell proliferation. Mutations in and subsequent loss of the p16 gene occur in PDAC at a rate higher than that reported in any other tumor type and results in Rb inactivation and unrestricted cellular growth. Therefore, strategies targeting downstream RAS pathway effectors combined with CDK4/6 inhibition (CDK4/6i) may have the potential to improve outcomes in this disease. Herein, we show that expression of p16 is markedly reduced in PDAC tumors compared with normal pancreatic or pre-neoplastic tissues. Combined MEK inhibition (MEKi) and CDK4/6i results in sustained downregulation of both ERK and Rb phosphorylation and a significant reduction in cell proliferation compared with monotherapy in human PDAC cells. MEKi with CDK4/6i reduces tumor cell proliferation by promoting senescence-mediated growth arrest, independent of apoptosis in vitro We show that combined MEKi and CDK4/6i treatment attenuates tumor growth in xenograft models of PDAC and improves overall survival over 200% compared with treatment with vehicle or individual agents alone in Ptf1acre/+ ;LSL-KRASG12D/+ ;Tgfbr2flox/flox (PKT) mice. Histologic analysis of PKT tumor lysates reveal a significant decrease in markers of cell proliferation and an increase in senescence-associated markers without any significant change in apoptosis. These results demonstrate that combined targeting of both MEK and CDK4/6 represents a novel therapeutic strategy to synergistically reduce tumor growth through induction of cellular senescence in PDAC.


Subject(s)
Cellular Senescence/drug effects , Cyclin-Dependent Kinase 4/metabolism , Cyclin-Dependent Kinase 6/metabolism , Mitogen-Activated Protein Kinase Kinases/metabolism , Protein Kinase Inhibitors/pharmacology , Signal Transduction/drug effects , Animals , Carcinoma, Pancreatic Ductal/drug therapy , Carcinoma, Pancreatic Ductal/metabolism , Carcinoma, Pancreatic Ductal/pathology , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Cyclin-Dependent Kinase 4/antagonists & inhibitors , Cyclin-Dependent Kinase 6/antagonists & inhibitors , Disease Models, Animal , Drug Synergism , Gene Expression Regulation, Neoplastic , Genes, p16 , Humans , Mice , Mice, Knockout , Mice, Transgenic , Protein Kinase Inhibitors/therapeutic use , Xenograft Model Antitumor Assays
9.
Elife ; 102021 02 26.
Article in English | MEDLINE | ID: mdl-33635271

ABSTRACT

Making choices about food affects the metabolism and lifespan of fruit flies.


Subject(s)
Aging , Drosophila melanogaster , Animals , Drosophila , Drosophila melanogaster/genetics , Longevity
10.
Elife ; 92020 10 20.
Article in English | MEDLINE | ID: mdl-33078707

ABSTRACT

The relationship between lipid metabolism and longevity remains unclear. Although fat oxidation is essential for weight loss, whether it remains beneficial when sustained for long periods, and the extent to which it may attenuate or augment lifespan remain important unanswered questions. Here, we develop an experimental handle in the Caenorhabditis elegans model system, in which we uncover the mechanisms that connect long-term fat oxidation with longevity. We find that sustained ß-oxidation via activation of the conserved triglyceride lipase ATGL-1, triggers a feedback transcriptional loop that involves the mito-nuclear transcription factor ATFS-1, and a previously unknown and highly conserved repressor of ATGL-1 called HLH-11/AP4. This feedback loop orchestrates the dual control of fat oxidation and lifespan, and shields the organism from life-shortening mitochondrial stress in the face of continuous fat oxidation. Thus, we uncover one mechanism by which fat oxidation can be sustained for long periods without deleterious effects on longevity.


Subject(s)
Caenorhabditis elegans/physiology , Feedback, Physiological , Lipid Metabolism/physiology , Longevity/physiology , Animals , Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/metabolism , Lipase/genetics , Lipase/metabolism , Oxidation-Reduction , Transcription Factors/genetics , Transcription Factors/metabolism
11.
J Neurogenet ; 34(3-4): 482-488, 2020.
Article in English | MEDLINE | ID: mdl-32619378

ABSTRACT

This review article highlights our efforts to decode the role of the nervous system in regulating intestinal lipid metabolism in Caenorhabditis elegans. Capitalizing on the prescient and pioneering work of Sydney Brenner and John Sulston in establishing C. elegans as an immensely valuable model system, we have uncovered critical roles for oxygen sensing, population density sensing and food sensing in orchestrating the balance between storing lipids and utilizing them for energy in the intestine, the major organ for lipid metabolism in this model system. Our long-term goal is to reveal the integrative mechanisms and regulatory logic that underlies the complex relationship between genes, environment and internal state in the regulation of energy and whole-body physiology.


Subject(s)
Caenorhabditis elegans/physiology , Lipid Metabolism/physiology , Neurosecretory Systems/physiology , Animals , Body Weight , Caenorhabditis elegans Proteins/physiology , Energy Metabolism , Feeding Behavior/physiology , Intestines/innervation , Oxygen , Population Density , Serotonin/physiology , Starvation/metabolism , Tachykinins/physiology
12.
Mol Cancer Res ; 18(4): 623-631, 2020 04.
Article in English | MEDLINE | ID: mdl-31949002

ABSTRACT

Lack of durable response to cytotoxic chemotherapy is a major contributor to the dismal outcomes seen in pancreatic ductal adenocarcinoma (PDAC). Extensive tumor desmoplasia and poor vascular supply are two predominant characteristics which hinder the delivery of chemotherapeutic drugs into PDAC tumors and mediate resistance to therapy. Previously, we have shown that STAT3 is a key biomarker of therapeutic resistance to gemcitabine treatment in PDAC, which can be overcome by combined inhibition of the Src and EGFR pathways. Although it is well-established that concurrent EGFR and Src inhibition exert these antineoplastic properties through direct inhibition of mitogenic pathways in tumor cells, the influence of this combined therapy on stromal constituents in PDAC tumors remains unknown. In this study, we demonstrate in both orthotopic tumor xenograft and Ptf1acre/+;LSL-KrasG12D/+;Tgfbr2flox/flox (PKT) mouse models that concurrent EGFR and Src inhibition abrogates STAT3 activation, increases microvessel density, and prevents tissue fibrosis in vivo. Furthermore, the stromal changes induced by parallel EGFR and Src pathway inhibition resulted in improved overall survival in PKT mice when combined with gemcitabine. As a phase I clinical trial utilizing concurrent EGFR and Src inhibition with gemcitabine has recently concluded, these data provide timely translational insight into the novel mechanism of action of this regimen and expand our understanding into the phenomenon of stromal-mediated therapeutic resistance. IMPLICATIONS: These findings demonstrate that Src/EGFR inhibition targets STAT3, remodels the tumor stroma, and results in enhanced delivery of gemcitabine to improve overall survival in a mouse model of PDAC.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , Carcinoma, Pancreatic Ductal/drug therapy , Pancreatic Neoplasms/drug therapy , Protein Kinase Inhibitors/pharmacology , STAT3 Transcription Factor/metabolism , src-Family Kinases/antagonists & inhibitors , Animals , Carcinoma, Pancreatic Ductal/metabolism , Carcinoma, Pancreatic Ductal/pathology , Dasatinib/administration & dosage , Dasatinib/pharmacology , Deoxycytidine/administration & dosage , Deoxycytidine/analogs & derivatives , Deoxycytidine/pharmacology , Disease Models, Animal , ErbB Receptors/antagonists & inhibitors , ErbB Receptors/metabolism , Erlotinib Hydrochloride/administration & dosage , Erlotinib Hydrochloride/pharmacology , Female , Humans , Mice , Mice, Nude , Pancreatic Neoplasms/metabolism , Pancreatic Neoplasms/pathology , STAT3 Transcription Factor/antagonists & inhibitors , Signal Transduction/drug effects , Stromal Cells/drug effects , Stromal Cells/metabolism , Stromal Cells/pathology , Survival Analysis , Xenograft Model Antitumor Assays , src-Family Kinases/metabolism , Gemcitabine
13.
PLoS Biol ; 17(12): e3000242, 2019 12.
Article in English | MEDLINE | ID: mdl-31805041

ABSTRACT

The ability to coordinate behavioral responses with metabolic status is fundamental to the maintenance of energy homeostasis. In numerous species including Caenorhabditis elegans and mammals, neural serotonin signaling regulates a range of food-related behaviors. However, the mechanisms that integrate metabolic information with serotonergic circuits are poorly characterized. Here, we identify metabolic, molecular, and cellular components of a circuit that links peripheral metabolic state to serotonin-regulated behaviors in C. elegans. We find that blocking the entry of fatty acyl coenzyme As (CoAs) into peroxisomal ß-oxidation in the intestine blunts the effects of neural serotonin signaling on feeding and egg-laying behaviors. Comparative genomics and metabolomics revealed that interfering with intestinal peroxisomal ß-oxidation results in a modest global transcriptional change but significant changes to the metabolome, including a large number of changes in ascaroside and phospholipid species, some of which affect feeding behavior. We also identify body cavity neurons and an ether-a-go-go (EAG)-related potassium channel that functions in these neurons as key cellular components of the circuitry linking peripheral metabolic signals to regulation of neural serotonin signaling. These data raise the possibility that the effects of serotonin on satiety may have their origins in feedback, homeostatic metabolic responses from the periphery.


Subject(s)
Acyl Coenzyme A/metabolism , Feeding Behavior/physiology , Serotonin/metabolism , Animals , Caenorhabditis elegans/metabolism , Caenorhabditis elegans Proteins/metabolism , Fatty Acids/metabolism , Feedback , Homeostasis , Intestines/physiology , Neurons/metabolism , Oxidation-Reduction , Peroxisomes/metabolism , Signal Transduction
15.
Mol Cell ; 73(5): 1001-1014.e8, 2019 03 07.
Article in English | MEDLINE | ID: mdl-30527540

ABSTRACT

In Parkinson's disease (PD), α-synuclein (αS) pathologically impacts the brain, a highly lipid-rich organ. We investigated how alterations in αS or lipid/fatty acid homeostasis affect each other. Lipidomic profiling of human αS-expressing yeast revealed increases in oleic acid (OA, 18:1), diglycerides, and triglycerides. These findings were recapitulated in rodent and human neuronal models of αS dyshomeostasis (overexpression; patient-derived triplication or E46K mutation; E46K mice). Preventing lipid droplet formation or augmenting OA increased αS yeast toxicity; suppressing the OA-generating enzyme stearoyl-CoA-desaturase (SCD) was protective. Genetic or pharmacological SCD inhibition ameliorated toxicity in αS-overexpressing rat neurons. In a C. elegans model, SCD knockout prevented αS-induced dopaminergic degeneration. Conversely, we observed detrimental effects of OA on αS homeostasis: in human neural cells, excess OA caused αS inclusion formation, which was reversed by SCD inhibition. Thus, monounsaturated fatty acid metabolism is pivotal for αS-induced neurotoxicity, and inhibiting SCD represents a novel PD therapeutic approach.


Subject(s)
Antiparkinson Agents/pharmacology , Drug Discovery/methods , Enzyme Inhibitors/pharmacology , Lipid Metabolism/drug effects , Metabolomics/methods , Neurons/drug effects , Parkinson Disease/drug therapy , Stearoyl-CoA Desaturase/antagonists & inhibitors , alpha-Synuclein/toxicity , Animals , Caenorhabditis elegans/drug effects , Caenorhabditis elegans/enzymology , Caenorhabditis elegans/genetics , Cell Line , Cerebral Cortex/drug effects , Cerebral Cortex/enzymology , Cerebral Cortex/pathology , Diglycerides/metabolism , Disease Models, Animal , Dopaminergic Neurons/drug effects , Dopaminergic Neurons/enzymology , Dopaminergic Neurons/pathology , Humans , Induced Pluripotent Stem Cells/drug effects , Induced Pluripotent Stem Cells/enzymology , Induced Pluripotent Stem Cells/pathology , Lipid Droplets/drug effects , Lipid Droplets/enzymology , Mice, Inbred C57BL , Mice, Transgenic , Molecular Targeted Therapy , Nerve Degeneration , Neural Stem Cells/drug effects , Neural Stem Cells/enzymology , Neural Stem Cells/pathology , Neurons/enzymology , Neurons/pathology , Oleic Acid/metabolism , Parkinson Disease/enzymology , Parkinson Disease/genetics , Parkinson Disease/pathology , Rats, Sprague-Dawley , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/enzymology , Saccharomyces cerevisiae/genetics , Stearoyl-CoA Desaturase/metabolism , Triglycerides/metabolism , alpha-Synuclein/genetics
16.
Mol Cancer Ther ; 18(2): 301-311, 2019 02.
Article in English | MEDLINE | ID: mdl-30404927

ABSTRACT

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy and is highly resistant to standard treatment regimens. Targeted therapies against KRAS, a mutation present in an overwhelming majority of PDAC cases, have been largely ineffective. However, inhibition of downstream components in the KRAS signaling cascade provides promising therapeutic targets in the management of PDAC and warrants further exploration. Here, we investigated Urolithin A (Uro A), a novel natural compound derived from pomegranates, which targets numerous kinases downstream of KRAS, in particular the PI3K/AKT/mTOR signaling pathways. We showed that treatment of PDAC cells with Uro A blocked the phosphorylation of AKT and p70S6K in vitro, successfully inhibited the growth of tumor xenografts, and increased overall survival of Ptf1aCre/+;LSL-KrasG12D/+;Tgfbr2flox/flox (PKT) mice compared with vehicle or gemcitabine therapy alone. Histologic evaluation of these Uro A-treated tumor samples confirmed mechanistic actions of Uro A via decreased phosphorylation of AKT and p70S6K, reduced proliferation, and increased cellular apoptosis in both xenograft and PKT mouse models. In addition, Uro A treatment reprogrammed the tumor microenvironment, as evidenced by reduced levels of infiltrating immunosuppressive cell populations such as myeloid-derived suppressor cells, tumor-associated macrophages, and regulatory T cells. Overall, this work provides convincing preclinical evidence for the utility of Uro A as a therapeutic agent in PDAC through suppression of the PI3K/AKT/mTOR pathway.


Subject(s)
Antineoplastic Agents, Phytogenic/administration & dosage , Carcinoma, Pancreatic Ductal/drug therapy , Coumarins/administration & dosage , Lythraceae/chemistry , Pancreatic Neoplasms/drug therapy , Signal Transduction/drug effects , Animals , Antineoplastic Agents, Phytogenic/pharmacology , Carcinoma, Pancreatic Ductal/metabolism , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Coumarins/pharmacology , Humans , Mice , Pancreatic Neoplasms/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Phosphorylation/drug effects , Proto-Oncogene Proteins c-akt/metabolism , TOR Serine-Threonine Kinases/metabolism , Xenograft Model Antitumor Assays
17.
Cancer Res ; 78(21): 6146-6158, 2018 11 01.
Article in English | MEDLINE | ID: mdl-30232221

ABSTRACT

Although smoking is a significant risk factor for pancreatic ductal adenocarcinoma (PDAC), the molecular mechanisms underlying PDAC development and progression in smokers are still unclear. Here, we show the role of cyclic AMP response element-binding protein (CREB) in the pathogenesis of smoking-induced PDAC. Smokers had significantly higher levels of activated CREB when compared with nonsmokers. Cell lines derived from normal pancreas and pancreatic intraepithelial neoplasm (PanIN) exhibited low baseline pCREB levels compared with PDAC cell lines. Furthermore, elevated CREB expression correlated with reduced survival in patients with PDAC. Depletion of CREB significantly reduced tumor burden after tobacco-specific nitrosamine 4-(methyl nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) treatment, suggesting a CREB-dependent contribution to PDAC growth and progression in smokers. Conversely, NNK accelerated PanIN lesion and PDAC formation via GM-CSF-mediated activation of CREB in a PDAC mouse model. CREB inhibition (CREBi) in mice more effectively reduced primary tumor burden compared with control or GM-CSF blockade alone following NNK exposure. GM-CSF played a role in the recruitment of tumor-associated macrophages (TAM) and regulatory T cell (Treg) expansion and promotion, whereas CREBi significantly reduced TAM and Treg populations in NNK-exposed mice. Overall, these results suggest that NNK exposure leads to activation of CREB through GM-CSF, promoting inflammatory and Akt pathways. Direct inhibition of CREB, but not GM-CSF, effectively abrogates these effects and inhibits tumor progression, offering a viable therapeutic strategy for patients with PDAC.Significance: These findings identify GM-CSF-induced CREB as a driver of pancreatic cancer in smokers and demonstrate the therapeutic potential of targeting CREB to reduce PDAC tumor growth.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/21/6146/F1.large.jpg Cancer Res; 78(21); 6146-58. ©2018 AACR.


Subject(s)
Carcinogens , Cyclic AMP Response Element-Binding Protein/metabolism , Gene Expression Regulation, Neoplastic , Granulocyte-Macrophage Colony-Stimulating Factor/metabolism , Nicotiana/adverse effects , Pancreatic Neoplasms/metabolism , Animals , Cell Line, Tumor , Cell Proliferation , Disease Models, Animal , Disease Progression , Humans , Immune System , Macrophages/metabolism , Mice , Mice, Nude , Mice, Transgenic , Neoplasm Transplantation , Nitrosamines/chemistry , Pancreatic Neoplasms/etiology , RNA, Small Interfering/metabolism , Risk Factors , Smoking/adverse effects
18.
Mol Metab ; 16: 76-87, 2018 10.
Article in English | MEDLINE | ID: mdl-30120064

ABSTRACT

OBJECTIVES: Extracts of the hops plant have been shown to reduce weight and insulin resistance in rodents and humans, but elucidation of the mechanisms responsible for these benefits has been hindered by the use of heterogeneous hops-derived mixtures. Because hop extracts are used as flavoring agents for their bitter properties, we hypothesized that bitter taste receptors (Tas2rs) could be mediating their beneficial effects in metabolic disease. Studies have shown that exposure of cultured enteroendocrine cells to bitter tastants can stimulate release of hormones, including glucagon-like peptide 1 (GLP-1). These findings have led to the suggestion that activation of Tas2rs may be of benefit in diabetes, but this tenet has not been tested. Here, we have assessed the ability of a pure derivative of a hops isohumulone with anti-diabetic properties, KDT501, to signal through Tas2rs. We have further used this compound as a tool to systematically assess the impact of bitter taste receptor activation in obesity-diabetes. METHODS: KDT501 was tested in a panel of bitter taste receptor signaling assays. Diet-induced obese mice (DIO) were dosed orally with KDT501 and acute effects on glucose homeostasis determined. A wide range of metabolic parameters were evaluated in DIO mice chronically treated with KDT501 to establish the full impact of activating gut bitter taste signaling. RESULTS: We show that KDT501 signals through Tas2r108, one of 35 mouse Tas2rs. In DIO mice, acute treatment stimulated GLP-1 secretion and enhanced glucose tolerance. Chronic treatment caused weight and fat mass loss, increased energy expenditure, enhanced glucose tolerance and insulin sensitivity, normalized plasma lipids, and induced broad suppression of inflammatory markers. Chronic KDT501 treatment altered enteroendocrine hormone levels and bile acid homeostasis and stimulated sustained GLP-1 release. Combined treatment with a dipeptidyl peptidase IV inhibitor amplified the incretin-based benefits of this pure isohumulone. CONCLUSIONS: Activation of Tas2r108 in the gut results in a remodeling of enteroendocrine hormone release and bile acid metabolism that ameliorates multiple features of metabolic syndrome. Targeting extraoral bitter taste receptors may be useful in metabolic disease.


Subject(s)
Cyclopentanes/metabolism , Receptors, G-Protein-Coupled/metabolism , Receptors, G-Protein-Coupled/physiology , Animals , Body Weight/drug effects , Cyclopentanes/pharmacology , Diabetes Mellitus, Type 2/metabolism , Disease Models, Animal , Enteroendocrine Cells/metabolism , Glucagon-Like Peptide 1/drug effects , Glucagon-Like Peptide 1/metabolism , Humulus/metabolism , Hypoglycemic Agents/pharmacology , Insulin Resistance/physiology , Intestinal Mucosa/metabolism , Intestines/physiology , Male , Mice , Mice, Inbred C57BL , Mice, Obese , Receptors, G-Protein-Coupled/drug effects , Signal Transduction/drug effects
19.
PLoS Genet ; 14(3): e1007305, 2018 03.
Article in English | MEDLINE | ID: mdl-29579048

ABSTRACT

The mechanisms by which the sensory environment influences metabolic homeostasis remains poorly understood. In this report, we show that oxygen, a potent environmental signal, is an important regulator of whole body lipid metabolism. C. elegans oxygen-sensing neurons reciprocally regulate peripheral lipid metabolism under normoxia in the following way: under high oxygen and food absence, URX sensory neurons are activated, and stimulate fat loss in the intestine, the major metabolic organ for C. elegans. Under lower oxygen conditions or when food is present, the BAG sensory neurons respond by repressing the resting properties of the URX neurons. A genetic screen to identify modulators of this effect led to the identification of a BAG-neuron-specific neuropeptide called FLP-17, whose cognate receptor EGL-6 functions in URX neurons. Thus, BAG sensory neurons counterbalance the metabolic effect of tonically active URX neurons via neuropeptide communication. The combined regulatory actions of these neurons serve to precisely tune the rate and extent of fat loss to the availability of food and oxygen, and provides an interesting example of the myriad mechanisms underlying homeostatic control.


Subject(s)
Caenorhabditis elegans/metabolism , Lipid Metabolism , Neuropeptides/metabolism , Oxygen/metabolism , Sensory Receptor Cells/metabolism , Animals , Cell Communication , Guanylate Cyclase/metabolism , Intestinal Mucosa/metabolism , Signal Transduction
20.
J Photochem Photobiol B ; 174: 209-216, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28800509

ABSTRACT

A novel pegylated multifunctional probe of Ormosil nanoparticles (PEGCDSIR820) loaded with Near Infrared dye (NIR; IR820) and a chemotherapeutic drug, Doxorubicin (DOX) was developed for cancer theranostic applications. PEGCDSIR820 nanoparticles had an average diameter of 58.2±3.1nm, zeta potential of -6.9±0.1mV in cell culture media and stability against aggregation in physiological buffers. The encapsulation efficiency of DOX was 65.0±3.0%, and that of IR820 was 76.0±2.1%. PEGCDSIR820 showed no cytotoxicity in ovarian cancer cells (Skov-3). The cytotoxicity markedly increased when Skov-3 cells incubated with PEGCDSIR820 particles were exposed to 808nm laser due to the combination of adjuvant hyperthermia (43°C) and enhanced DOX release. Exposure to laser enhanced the release of DOX, 45% of DOX release was observed in 3h compared to 23% without laser exposure. Confocal imaging in Skov-3 cells showed that the combination of hyperthermia due to NIR exposure and release of DOX caused cell necrosis. Furthermore, in spheroids exposed to NIR laser penetration of DOX was deeper compared to the absence of laser exposure. Skov-3 spheroids incubated with pegylated nanoparticles for 24h and exposed to laser showed 94% reduction in cell viability. Encapsulation of IR820 in PEGCDSIR820 increased the in-vivo elimination half-life to 41.0±7.2h from 30.5±0.5h of free IR820.


Subject(s)
Doxorubicin/chemistry , Drug Liberation , Nanoparticles/chemistry , Ovarian Neoplasms/pathology , Polyethylene Glycols/chemistry , Siloxanes/chemistry , Spheroids, Cellular/metabolism , Cell Line, Tumor , Doxorubicin/metabolism , Doxorubicin/pharmacology , Drug Carriers/chemistry , Drug Carriers/pharmacokinetics , Female , Humans , Kinetics , Particle Size , Temperature , Theranostic Nanomedicine , Tissue Distribution
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