Project description:To determine whether suppression of IGF-1 signaling in was synergistic with inhibition of autophagy in PDAC, and to identify transcriptional response illicited mice were injeced with KPC MT4 cells s.c. and treated with vector BMS754807 or hydroxychloroquine alone or incombination. RNA was isolated from median tumors from each group and transcriptomics conducted
Project description:Autophagy is activated in pancreatic ductal adenocarcinoma (PDAC) and is currently being considered a promising therapeutic target in clinical trials. PDAC is a highly lethal disease with incidence rate equalling mortality rate. Main reasons for PDAC lethality are late-stage diagnosis, high agressiveness and metastatic rate, lack of effective treatments as well as specific diagnostic markers. Here we show that varying levels of the Autophagy related gene 5 (Atg5) determine pancreatic tumor formation and malignancy. While homozygous deletion of Atg5 blocks tumor progression in an in vivo model of PDAC, heterozygous deletion increases tumor aggressiveness and metastasis. Further analyses reveal that monoallelic loss of Atg5 affects mitochondrial homeostasis, changes intracellular calcium oscillations, heightens extracellular cathepsin activities , and promotes a pro-tumorigenic inflammatory microenvironment collectively enhancing tumor cell migration, invasion, and metastasis. Future treatments should take into account that variations in the autophagy pathway may have opposing effects on pancreatic tumor load, especially considering the multitude of autophagy inhibitors currently tested in clinical trials.
Project description:Decreased skeletal muscle strength and mitochondrial dysfunction are characteristic of diabetes. Action of insulin through insulin receptor (IR) and IGF-1 receptor (IGF1R) maintain muscle mass via suppression of FoxOs, but whether FoxO activation coordinates atrophy in concert with mitochondrial dysfunction is unknown. In the absence of systemic glucose or lipid abnormalities, muscle-specific IR knockout (MIRKO) or combined IR/IGF1R knockout (MIGIRKO) impaired mitochondrial respiration, decreased ATP production, and increased ROS. These mitochondrial abnormalities were not present in muscle-specific IR/IGF1R and FoxO1/3/4 quintuple knockout mice (QKO). Although autophagy was increased when IR/IGF1R were deleted in muscle, mitophagy was not increased. Mechanistically, RNA-seq revealed that complex-I core subunits were decreased in MIGIRKO muscle, and these were reversed with FoxO knockout. Thus, insulin-deficient diabetes or loss of insulin/IGF-1 action in muscle decreases complex-I driven mitochondrial respiration and supercomplex assembly, in part by FoxO-mediated repression of Complex-I subunit expression.
Project description:We previously reported that increased expression of IGF1R in mouse and human beta-cells is a marker of older beta-cells; however, its contribution to age-related dysfunction and cellular senescence remains to be determined. In this study, we explored the direct role of IGF1R in beta-cell function and senescence using inducible beta-cell specific IGF1R knockdown (betaIgf1rKD) mice. Adult betaIgf1rKD mice showed improved glucose clearance and glucose-induced insulin secretion, accompanied by decreased p21Cip1 protein expression in beta-cells. RNASeq of islets isolated from these betaIgf1rKD mice revealed restoration of 3 signaling pathways known to be downregulated by aging: sulfide oxidation, autophagy, and mTOR signaling. Additionally, deletion of IGF1R in mouse beta-cells increased transcription of genes important for maintaining beta-cell identity and function, such as Mafa, Nkx6.1, and Kcnj11, while decreasing senescence-related genes, such as Cdkn2a, Il1b, and Serpine 1. These results suggest that IGF1R signaling plays a causal role in aging-induced beta-cell dysfunction.
Project description:IGF1 and IGF1 receptors (IGF1R) are present in the adult heart and have been shown to be essential for myocardial performance. Insulin-like growth factor 1 (IGF1) is produced in numerous tissues particularly by the liver in response to growth hormone stimulation and is an important factor in the regulation of post-natal growth and development. We have generated and characterized transgenic mice over-expressing the IGF1R. We crossed IGF1R transgenic mice with dominant negative (dn)PI3K (p110) and with constitutively active (ca)PI3K(p110) transgenic mice. Expression profiling was performed on the ventricles of IGF1R, IGF1R-caPI3K, IGF1R-dnPI3K, caPI3K, dnPI3K transgenic female mice at 3 months of age. Non-transgenic littermates were used as controls.
Project description:Despite a high degree of homology, insulin and IGF-1 receptors (IR/IGF1R) mediate distinct cellular and physiological functions. Here, using chimeric and site-mutated receptors, we demonstrate how domain differences between IR and IGF1R contribute the distinct functions of these receptors. Receptors with the intracellular domain of IGF1R show increased activation of Shc and Gab-1 and more potent regulation of genes involved in proliferation, corresponding to its higher mitogenic activity. Conversely, receptors with the intracellular domain of IR display higher IRS-1 phosphorylation, stronger regulation of genes in metabolic pathways and more dramatic glycolytic responses to hormonal stimulation. We generated mouse brown preadipocytes in which both insulin and IGF-1 receptors (IR and IGF1R) had been genetically inactivated using Cre-lox recombination. These IR and IGF1R DKO cells were then reconstituted with wild-type mouse IR, IGF1R, or one of two chimeric receptors: IR/IGF1R with the IR extracellular domain (ECD) fused to the IGF1R transmembrane and intracellular domains (ICD) and IGF1R/IR with the ECD of IGF1R fused to the ICD domains of IR. Three independent clones for each line were used for the study. For expression analysis, we serum-starved the preadipocytes clones overnight and stimulated cells with 100 nM insulin, IGF-1 or vehicle for 6 h, and subjected the cellular RNA to analysis using Affymetrix Mouse Gene 2.0 ST arrays.
Project description:Insulin resistance (IR) is likely to induce metabolic syndrome and type 2 diabetes mellitus (T2DM). Gluconeogenesis (GNG) is a complex metabolic process that may result in glucose generation from certain non-carbohydrate substrates. Chinese herbal medicine astragalus polysaccharides and berberine have been documented to ameliorate IR, and combined use of astragalus polysaccharide (AP) and berberine (BBR) are reported to synergistically produce an even better effect. However, what change may occur in the GNG signaling pathway of IR-HepG2 cells in this synergistic effect and whether AP-BBR attenuates IR by regulating the GNG signaling pathway remain unclear. For the first time, we discovered in this study that the optimal time of IR-HepG2 cell model formation was 48 hours after insulin intervention. AP-BBR attenuated IR in HepG2 cells and the optimal concentration was 10mg. AP-BBR reduced the intracellular H2O2 content with no significant effect on apoptosis of IR-HepG2 cells. In addition, a rapid change was observed in intracellular calcium current of the IR-HepG2 cell model, and AP-BBR intervention attenuated this change markedly. The gene sequencing results showed that the GNG signaling pathway was one of the signaling pathways of AP-BBR to attenuate IR in IR-Hepg2 cells. The expression of p-FoxO1Ser256 and PEPCK protein was increased and the expression of GLUT2 protein was decreased significantly in the IR-HepG2 cell model, and both of these effects could be reversed by AP-BBR intervention. AP-BBR attenuated IR in IR-HepG2 cells, probably by regulating the GNG signaling Pathway.
Project description:To investigate genes that might influence resistance to infection through IGF1R, we screened human breast cancer-derived OCUB-M cells transfected with expression vector encoding IGF1R using microarray analysis. Keywords: overexpression comparison
Project description:Insulin and IGF-1 receptors (IR/IGF1R) are highly homologous and share similar signaling systems, but each has a unique physiological role, with IR primarily regulating metabolic homeostasis and IGF1R regulating mitogenic control and growth. Here, we show that replacement of a single amino acid at position 973, just distal to the NPEY motif in the intracellular juxtamembrane region, from leucine, which is highly-conserved in IRs, to phenylalanine, the highly-conserved homologous residue in IGF1Rs, results in decreased IRS-1-PI3K-Akt-mTORC1 signaling and increased of Shc-Gab1-MAPK-cell cycle signaling. As a result, cells expressing L973F-IR exhibit decreased insulin-induced glucose uptake, increased cell growth and impaired receptor internalization. Mice with knockin of the L973F-IR show similar alterations in signaling in vivo, and this leads to decreased insulin sensitivity, a modest increase in growth and decreased weight gain when challenged with high-fat diet. Thus, leucine973 in the juxtamembrane region of the IR acts is a crucial residue differentiating IR signaling from IGF1R signaling.
Project description:In this study, we investigated the impact of autophagy inhibition in cancer cell on the tumor immune microenvironment (TIME) of orthotopic syngeneic pancreatic ductal adenocarcinoma (PDAC) tumors. Dendritic cells (DCs) in the cancer cell autophagy inhibited tumors showed significantly higher expression of genes related to DC functions such as antigen-presentation, migration, IFN response, compared to control tumors. Our results indicate that autophagy inhibition in cancer cells induce the enhancement of adoptive tumor immunity via DC activation in PDAC.