Emerging role of Transforming Growth Factor-beta and Galectin-3 Binding Protein in cancer progression: from preclinical models to clinical implications
Progetto BACKGROUND. Galectin-3 Binding Protein (Gal-3BP) is a secreted glycoprotein involved in cancer progression and immune regulation. Experimental data indicate that Gal-3BP has pro-metastatic properties resulting from its ability to mediate cell to cell and cell to extracellular matrix (ECM) adhesion. Consistently, a role for Gal-3BP as biomarker of advanced cancer and poor prognosis has been recognized. Transforming Growth Factor (TGF)-beta is a pleiotropic cytokine that in cancer can take on a role of tumor promoter, favoring invasion and metastasis. Recently, we found that TGF-beta is a potent stimulator of Gal-3BP expression. Moreover, analysis of the public platform cBioPortal revealed that the expression of Gal-3BP positively correlates with that of TGF-beta and the contemporary expression of both is associated with increased mortality in patients with different types of cancer, indicating a synergism between these two factors.
HYPOTHESIS. We hypothesize that: (i) the pro-metastatic activity of TGF-beta is at least in part due to its ability to stimulate Gal-3BP expression and (ii) inhibiting Gal-3BP could block TGF-induced metastatic spreading.
AIMS. We aim to demonstrate that Gal-3BP is involved in the TGF-beta-regulated mechanisms responsible for cancer progression. We will evaluate the role played by Gal-3BP in the metastatic process triggered by TGF-beta in vitro (aim 1) and in vivo (aim 2). In addition, given the immunosuppressive properties of TGF-beta, we will evaluate the role of Gal-3BP in the modulation of this effect (aim 3). Finally, we will correlate serum levels of TGF-beta/Gal-3BP with the clinical outcome of patients affected by different types of advanced/metastatic cancer treated with immune checkpoint inhibitors (ICIs) (aim 4).
EXPERIMENTAL DESIGN. The pro-metastatic effect of TGF-beta, i.e. induction of epithelial to mesenchymal transition (EMT)-related markers and enhancement of cell migration/invasiveness, will be evaluated in wild-type cancer cells or in cells in which Gal-3BP has been inhibited either by gene silencing or the addition of a blocking antibody (SP-2). In these latter conditions, a significant reduction of the pro-metastatic effect of TGF-beta is expected. Murine tumor xenografts will be used to evaluate the involvement of Gal-3BP in the TGF-beta-induced tumor growth and metastasis. To investigate the role of Gal-3BP in the immunosuppressive effect of TGF-beta we will measure cytokine production in CD4+ T cells and cytotoxic activity (NK/LAK) in peripheral blood mononuclear cells (PBMC), along with the generation of Treg. In these experiments CD4+ cells or PBMC will be stimulated with TGF-beta or recombinant Gal-3BP, in the presence or absence of SP-2 antibody. Finally, the prognostic relevance of TGF-beta/Gal-3BP in patients with advanced/metastatic cancer treated with ICIs will be determined by correlating TGF-beta/Gal-3BP serum levels with objective response and progression-free survival.