Hyaluronan action on monocytes/macrophages: a link between tumor angiogenesis and TSG-6 expression levels.

FIORELLA SPINELLI; DAIANA VITALE; ANTONELLA ICARDI; INA SEVIC; ILARIA CAON; ALEJANDRA BRANDONE; PAULA GIANNONI; VIRGINIA SATURNO; ALBERTO PASSI; MARIANA GARCÍA; LAURA ALANIZ

Mar del Plata

Congreso; LXVI Reunión Anual de la Sociedad Argentina de Inmunología 2018 conjunta SAIF SAIC; 2018

SAI SAIC SAFIS

Hyaluronan (HA) is a glycosaminoglycan able to modulate immune and angiogenic responses. At homeostasis, high-molecular-weight(HMW) HA is predominant whereas the low-molecular-weight(LMW) is present in inflammation. HA binds to several receptors as well as HA-binding protein, TSG-6. It is involved in ECM remodeling affecting HA function and inflammation. HA in tumor recruits associated-macrophages and regulates their angiogenesis action by unclear mechanisms.Aim: To evaluate the TSG-6 levels and angiogenic behavior of human monocytes/macrophages (MO) preconditioned with HA (HMW or LMW) in breast and colorectalcarcinoma.Methods: MDA-MB 231 breast or LoVo colorectalcarcinoma tumor lysates (TL) were prepared by freeze-thaw cycles. MO from PBMCs were pulsed with TL plus HA(20ug/ml) LMW(1,5x106Da) or HMW(2x105Da) for 24h. MO were characterized with CD14, HLA, CD80 and CD206 by flow cytometry. VEGF levels were evaluated by ELISA. IL-8, FGF-2 and TSG-6 expression levels were evaluated by RT-qPCR. TSG-6 was analyzed through western blot. For the xenograft mouse model MDA-MB-231 or LoVo cells were inoculated. After 9days, MO pulsed or/not with HA were inoculated sc within the tumor. Animals were euthanatized at day 29, tumors were fixed and stained with: i)Lectin GSLI-FITC for vasculature detection and ii)HA-binding protein and Ab-anti-TSG-6. Results: HA treatments did not modify the expression of MO cell surface markers. MO treated with MDA TL plus HA-HMW: i)VEGF(329,5±12,79pg/ml), IL-8(NRQ:5,761±1,461) and FGF-2(NRQ:2,972±0,8020) levels increased and ii)TSG-6(NRQ:5,860±2,711) mRNA levels diminished significantly. However, these factors showed no significant difference in MO treated with LoVo TL with/without HA. Mice inoculated with MO plus HA-HMW increased its vasculature(1,759±0,1173AU) and diminished TSG-6(1,820±0,4308AU) in MDA model. While in the LoVo model no differences were found among treatments. Conclusion: HA-HMW modulates MO angiogenic behavior and TSG-6 levels in breast carcinoma, but not in colon carcinoma. Our results indicate that MO HA- modulation depends of its molecular weight but also tumoral factors, as TSG-6.