TY - JOUR T1 - Thrombospondin-4 mediates hyperglycemia- and TGF-beta-induced inflammation in breast cancer JF - bioRxiv DO - 10.1101/2020.01.03.894436 SP - 2020.01.03.894436 AU - Santoshi Muppala AU - Roy Xiao AU - Jasmine Gajeton AU - Irene Krukovets AU - Dmitriy Verbovetskiy AU - Olga Stenina-Adognravi Y1 - 2020/01/01 UR - http://biorxiv.org/content/early/2020/12/14/2020.01.03.894436.abstract N2 - Inflammation drives the growth of tumors and is an important predictor of cancer aggressiveness. CD68, a marker of tumor-associated macrophages (TAM), is routinely used as a marker to aid in prognosis and treatment choices for breast cancer.We report that thrombospondin-4 (TSP-4) mediates breast cancer inflammation and growth in mouse models in response to hyperglycemia and TGF-beta by increasing TAM infiltration and production of inflammatory signals in tumors. Analysis of breast cancers and non-cancerous tissue specimens from hyperglycemic patients revealed that levels of TSP-4 and of macrophage marker CD68 are upregulated in diabetic tissues. TSP-4 was co-localized with macrophages in cancer tissues. Bone-marrow-derived macrophages (BMDM) responded to high glucose and TGF-beta by upregulating TSP-4 production and expression, as well as the expression of inflammatory markers.We report a novel function for TSP-4 in breast cancer: regulation of TAM infiltration and inflammation. The results of our study provide new insights into regulation of cancer growth by hyperglycemia and TGF-beta and suggest TSP-4 as a potential therapeutic target.Novelty and Impact Thrombospondin-4 (TSP-4) is a secreted extracellular protein that belongs to the family of matricellular proteins. TSP-4 is one of the top 1% of proteins upregulated in several cancers, including breast cancer. Inflammation and infiltration of macrophages drive cancer progression and metastasis and are clinically important markers of cancer aggressiveness and critical consideration in the process of selection of the appropriate therapeutic approaches. We report that TSP-4 promotes breast cancer inflammation and infiltration of macrophages and mediates the effects of hyperglycemia and TGF-beta on cancer growth and inflammation. Our work describes a role for TSP-4 in cancer inflammation and identifies the pathways, in which increased levels of TSP-4 mediate cancer growth.Competing Interest StatementThe authors have declared no competing interest.AbbreviationsActBbeta-actin geneANOVAAnalysis of varianceArg1Arginase 1BMDMbone-marrow-derived macrophagesCcl2chemokine ligand 2, also known as monocyte chemoattractant protein 1CD38Cluster of Differentiation 38CD68Cluster of Differentiation 68cDNAcomplementary DNA (deoxyribonucleic acid)Col Icollagen ICol IVcollagen IVDMEMDulbecco's Modified Eagle MediumECendothelial cellECMextracellular matrixEgr2early growth response protein 2GapdhGlyceraldehyde 3-phosphate dehydrogenase geneHbAc1glycated hemoglobinIl-6interleukin-6iNOSInducible Nitric Oxide SynthaseIPintraperitonealM-CSFMacrophage Colony Stimulating FactorMCP-1macrophage chemoattractant proteinmRNAMessenger RNANIHNational Institutes of HealthNos2Nitric Oxide Synthase 2 (Inducible Nitric Oxide Synthase) geneP387-TSP4-KIknock-in mice with A to P mutation in position 387Rn18s18S ribosomal RNART-PCRReverse transcription polymerase chain reactionS.E.M.standard error of the meanSTZstreptozotocinTAMtumor-associated macrophagesTGF-betaTransforming Growth Factor-betaThbs4TSP-4 geneTNF-alphaTumor necrosis factor alphaTSP-4thrombospondin-4vWFvon Willebrand factorWTwild type ER -