Crosstalk between tumor cells and lymphocytes modulates heparanase expression

Thérèse Rachell Theodoro,Renan Pelluzzi Cavalheiro,Giselle Zenker Justo,Maria Aparecida Silva Pinhal,Leandro Luongo Matos,Helena Bonciani Nader

doi:10.1186/s12967-019-1853-z

Abstract

BackgroundHeparanase (HPSE) is an endo-beta-glucuronidase that degrades heparan sulfate (HS) chains on proteoglycans. The oligosaccharides generated by HPSE promote angiogenesis, tumor growth and metastasis. Heparanase-2 (HPSE2), a close homolog of HPSE, does not exhibit catalytic activity. Previous studies have demonstrated that serum or plasma from breast cancer patients showed increased expression of both heparanases in circulating lymphocytes. The aim of this study was to better understand the mechanisms involved in the upregulation of heparanases in circulating lymphocytes.MethodsLymphocytes collected from healthy women were incubated in the presence of MCF-7 breast cancer cells (co-culture) to stimulate HPSE and HPSE2 overexpression. The protein level of heparanases was evaluated by immunocytochemistry, while mRNA expression was determined by quantitative RT-PCR.ResultsThe medium obtained from co-culture of MCF-7 cells and circulating lymphocytes stimulated the expression of HPSE and HPSE2. Previous treatment of the co-culture medium with an anti-heparan sulfate proteoglycan antibody or heparitinase II inhibited the upregulation of heparanases in circulating lymphocytes. The addition of exogenous heparan sulfate (HS) enhanced the expression of both heparanases. Moreover, the co-cultured cells, as well as MCF-7 cells, secreted a higher number of exosomes expressing an increased level of HS compared to that of the exosomes secreted by circulating lymphocytes from women who were not affected by cancer.ConclusionsThe results revealed that HS is likely responsible for mediating the expression of heparanases in circulating lymphocytes. HS secreted by tumor cells might be carried by exosome particles, confirming the key role of tumor cells, as well as secreted HS, in upregulating the expression of heparanases, suggesting a possible mechanism of crosstalk between tumor cells and circulating lymphocytes.

Highlights

Heparanase (HPSE) is an endo-beta-glucuronidase that degrades heparan sulfate (HS) chains on proteoglycans
Among the heparanase-inhibiting compounds, we highlight high sulfonated mannan oligosaccharide (PI88), synthetic mixture of oligosaccharides derived from heparin) (PG545) and SST0001, which are currently in clinical trials [31]
As described previously, Peripheral blood mononuclear cells (PBMC) were allowed to adhere in cell culture in the presence of phorbol ester (PMA), and after 24 h, non-adherent cells were incubated with the plasma of breast cancer patients; the expression of HPSE and HPSE2 was significantly enhanced in these cells

Summary

Introduction

Heparanase (HPSE) is an endo-beta-glucuronidase that degrades heparan sulfate (HS) chains on proteoglycans. Previous studies have demonstrated that serum or plasma from breast cancer patients showed increased expression of both heparanases in circulating lymphocytes. The glycosaminoglycan chains of heparan sulfate proteoglycan (HSPG) can be degraded by heparanase (HPSE), generating oligosaccharides that intensify the effects of growth factors, cytokines, and angiogenic factors, triggering cell proliferation, cell differentiation, and angiogenesis, which favor tumor development [2,3,4,5]. It was demonstrated that among all triple-negative breast cancers, rich lymphocyte infiltration represented a good prognosis that could derive benefit from immune checkpoint inhibitor therapy, enhancing the anticancer activity of the immune system [13]. Theodoro and colleagues observed increased levels of HPSE and HPSE2 in peripheral blood mononuclear cells (PBMCs) of breast cancer patients [18]. High and low extracellular vesicle concentrations have been shown to have differential effects that dictate the modulatory effects on PBMCs [23]

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