Uticaj dijabetes melitusa na rast i progresiju mišjeg tumora dojke

Abstract

Osobe obolele od dijabetes melitusa imaju veću incidencu i mortalitet od tumora. Prethodne studije su pokazale da oksidativni stres, koji nastaje kao posledica hiperglikemije, ubrzava metastaziranje. U ovom istraživanju dijabetes je indukovan jednom visokom dozom streptozotocina u cilju ispitivanja uticaja dijabetes melitusa na rast tumora i modulaciju antitumorskog imunskog odgovora, u modelu 4T1 karcinoma dojke u BALB/c miševa. Dijabetes melitus je ubrzao pojavu, rast i masu primarnog tumora što je praćeno smanjenom citotoksičnošću NK ćelija prema 4T1 ćelijama, in vitro. Dijabetes melitus je značajno smanjio procentualnu zastupljenost NKG2D+, perforin+, granzim+, IFN-γ+ i IL-17+ NK ćelija, dok je povećao ekspresiju PD-1 molekula i produkciju IL-10 u NK ćelijama u slezini. Dijabetes je značajno smanjio procenat NKG2D+ NK ćelija i povećao procenat PD-1+ NK ćelija i u primarnom tumoru. Dijabetično stanje je povećalo akumulaicju IL-10+ Tregs i TGF-β+ mijeloidnih supresorskih ćelija (MDSCs) u slezini i primarnom tumoru. Dijabetični serum je u in vitro uslovima značajno povećao procenat KLRG-1+ i PD-1+ NK ćelija, smanjio procenat IFN-γ+ NK ćelija, ekspresiju NKp46 i produkciju perforina, granzima, CD107a i IL-17 u NK ćelijama u poređenju sa serumom kome je dodata glukoza odnosno sa kontrolnim serumom. Dijabetes melitus je značajno povećao ekspresiju inducibilne azot monoksid sintaze (iNOS) i indolamin 2,3-dioksigenaze (IDO) u slezinskim MDSCs i dendritskim ćelijama (DC) miševa pre indukcije tumora. Specifični inhibitor indolamin 2,3-dioksigenaze, 1-metil-DL- triptofan, je gotovo u potpunosti povratio fenotip NK ćelija kultivisanih u dijabetičnom serumu. Ovi rezultati ukazuju da dijabetes melitus ubrzava rast tumora povećanom akumulacijom imunosupresivnih ćelija i supresijom NK ćelija aktivnošću enzima IDO.

Diabetic patients have higher incidence and mortality of cancer. Recent study revealed that hyperglycemiainduced oxidative stress is involved in the acceleration of tumor metastasis. We used model of high dose streptozotocin-induced diabetes to investigate its effect on tumor growth and modulation of antitumor immune response of 4T1 murine breast cancer in BALB/c mice. Diabetes accelerated tumor appearance, growth and weight, which was associated with decreased NK cells cytotoxicity against 4T1 tumor cells in vitro. Diabetes reduced frequencies of systemic NKG2D+, perforin+, granzyme+, IFN-γ+ and IL-17+ NK cells, while increased level of PD-1 expression and production of IL-10 in NK cells. Diabetes decreased percentage of NKG2D+NK cells and increased percentage of PD-1+ NK cells also in primary tumor. Diabetes increased accumulation of IL-10+ Tregs and TGF-β+ myeloid derived suppressor cells (MDSCs) in spleen and tumor. Diabetic sera in vitro significantly increased percentage of KLRG-1+ and PD-1+ NK cells, decreased percentage of IFN-γ+NK cells, expression of NKp46 and production of perforin, granzyme, CD107a and IL-17 per NK cell in comparison to glucose added mouse sera and control sera. Significantly increased percentages of inducible nitric oxide synthase (iNOS) and indoleamine 2,3-dioxygenase (IDO) producing MDSCs and dendritic cells (DC) were found in the spleens of diabetic mice prior to tumor induction. 1-methyl-DLtryptophan, specific IDO inhibitor, almost completely restored phenotype of NK cells cultivated in diabetic sera. These findings indicate that diabetes promotes breast cancer growth at least in part through increased accumulation of immunosuppressive cells and IDO mediated attenuation of NK cells