RESUMO
OBJECTIVE: The mechanisms underlying type 2 diabetes resolution after Roux-en-Y gastric bypass (RYGB) are unclear. We suspected that glucose excretion may occur in the small bowel based on observations in humans. The aim of this study was to evaluate the mechanisms underlying serum glucose excretion in the small intestine and its contribution to glucose homeostasis after bariatric surgery. DESIGN: 2-Deoxy-2-[18F]-fluoro-D-glucose (FDG) was measured in RYGB-operated or sham-operated obese diabetic rats. Altered glucose metabolism was targeted and RNA sequencing was performed in areas of high or low FDG uptake in the ileum or common limb. Intestinal glucose metabolism and excretion were confirmed using 14C-glucose and FDG. Increased glucose metabolism was evaluated in IEC-18 cells and mouse intestinal organoids. Obese or ob/ob mice were treated with amphiregulin (AREG) to correlate intestinal glycolysis changes with changes in serum glucose homeostasis. RESULTS: The AREG/EGFR/mTOR/AKT/GLUT1 signal transduction pathway was activated in areas of increased glycolysis and intestinal glucose excretion in RYGB-operated rats. Intraluminal GLUT1 inhibitor administration offset improved glucose homeostasis in RYGB-operated rats. AREG-induced signal transduction pathway was confirmed using IEC-18 cells and mouse organoids, resulting in a greater capacity for glucose uptake via GLUT1 overexpression and sequestration in apical and basolateral membranes. Systemic and local AREG administration increased GLUT1 expression and small intestinal membrane translocation and prevented hyperglycaemic exacerbation. CONCLUSION: Bariatric surgery or AREG administration induces apical and basolateral membrane GLUT1 expression in the small intestinal enterocytes, resulting in increased serum glucose excretion in the gut lumen. Our findings suggest a novel, potentially targetable glucose homeostatic mechanism in the small intestine.
Assuntos
Glicemia/metabolismo , Fluordesoxiglucose F18/metabolismo , Intestino Delgado/metabolismo , Anfirregulina/farmacologia , Animais , Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Derivação Gástrica , Transportador de Glucose Tipo 1/metabolismo , Glicólise , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Ratos , Ratos Endogâmicos OLETF , Transdução de Sinais/efeitos dos fármacosRESUMO
Integrin beta 4 (ITGB4) overexpression in cancer cells contributes to cancer progression. However, the role of stromal ITGB4 expression in cancer progression remains poorly understood, despite stromal ITGB4 overexpression in malignant cancers. In our study, ITGB4-overexpressing triple negative breast cancer (TNBC) cells provided cancer-associated fibroblasts (CAFs) with ITGB4 proteins via exosomes, which induced BNIP3L-dependent mitophagy and lactate production in CAFs. In coculture assays, the ITGB4-induced mitophagy and glycolysis were suppressed in CAFs by knocking down ITGB4 or inhibiting exosome generation in MDA-MB-231, or blocking c-Jun or AMPK phosphorylation in CAFs. ITGB4-overexpressing CAF-conditioned medium promoted the proliferation, epithelial-to-mesenchymal transition, and invasion of breast cancer cells. In a co-transplant mouse model, MDA-MB-231 made a bigger tumor mass with CAFs than ITGB4 knockdown MDA-MB-231. Herein, we presented how TNBC-derived ITGB4 protein triggers glycolysis in CAFs via BNIP3L-dependent mitophagy and suggested the possibility that ITGB4-induced mitophagy could be targeted as a cancer therapy.
Assuntos
Fibroblastos Associados a Câncer/patologia , Exossomos/metabolismo , Integrina beta4/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Animais , Mama/patologia , Mama/cirurgia , Fibroblastos Associados a Câncer/metabolismo , Linhagem Celular Tumoral , Técnicas de Cocultura , Meios de Cultivo Condicionados , Transição Epitelial-Mesenquimal , Feminino , Técnicas de Silenciamento de Genes , Glicólise , Humanos , Integrina beta4/genética , Proteínas de Membrana/metabolismo , Camundongos , Mitofagia , Comunicação Parácrina , Cultura Primária de Células , Proteínas Proto-Oncogênicas/metabolismo , Neoplasias de Mama Triplo Negativas/cirurgia , Células Tumorais Cultivadas , Proteínas Supressoras de Tumor/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Tumor growth increases compressive stress within a tissue, which is associated with solid tumor progression. However, very little is known about how compressive stress contributes to tumor progression. Here, we show that compressive stress induces glycolysis in human breast cancer associated fibroblast (CAF) cells and thereby contributes to the expression of epithelial to mesenchymal (EMT)- and angiogenesis-related genes in breast cancer cells. Lactate production was increased in compressed CAF cells, in a manner dependent on the expression of metabolic genes ENO2, HK2, and PFKFB3. Conditioned medium from compressed CAFs promoted the proliferation of breast cancer cells and the expression of EMT and/or angiogenesis-related genes. In patient tissues with high compressive stress, the expression of compression-induced metabolic genes was significantly and positively correlated with EMT and/or angiogenesis-related gene expression and metastasis size. These findings illustrate a mechanotransduction pathway involving stromal glycolysis that may be relevant also for other solid tumours.