Serine Protease Inhibitor Kunitz-Type 2 Is Downregulated in Myelodysplastic Syndromes and Modulates Cell–Cell Adhesion

Abstract

Myelodysplastic syndromes (MDS) are clonal disorders involving hematopoietic stem cells (HSC) characterized by ineffective hematopoiesis. In addition to HSC defects, a defective hematopoiesis supporting capacity of mesenchymal stromal cells (MSCs) in the microenvironment niche has been implicated in MDS pathophysiology. The interaction between the dysfunctional MSCs MDS and HSC regulates diverse adhesion-related processes, such as progenitor cell survival, proliferation, differentiation, and self-renewal. As previously reported, a microarray analysis identified serine protease inhibitor kunitz-type 2 (SPINT2), an inhibitor of hepatocyte growth factor (HGF) activation, to be downregulated in MSCs from MDS patients. To define the role of SPINT2 in MDS hematopoietic microenvironment, an analysis of the effect of SPINT2 silencing in MSCs was carried out. We herein reported significantly lower levels of SPINT2 whereas HGF was expressed at higher levels in MSCs from MDS patients compared with healthy controls. SPINT2 underexpression results in an increased expression, production, and secretion of HGF and stromal cell-derived factor 1 (SDF-1) by MSCs. An increased adhesion of normal HSC or malignant cells onto MSCs silenced for SPINT2 was also observed. The altered MSCs adhesion in SPINT2-knockdown cells was correlated with increased CD49b and CD49d expression and with a decrease in CD49e expression. Our results suggest that the SPINT2 underexpression in the MSC from MDS patients is probably involved in the adhesion of progenitors to the bone marrow niche, through an increased HGF and SDF-1 signaling pathway.

Up‐regulation of SPINT2/HAI‐2 by Azacytidine in bone marrow mesenchymal stromal cells affects leukemic stem cell survival and adhesion

“…Significant decreases in SPINT2 mRNA (by 65 ± 3%, P < 0.001) and HAI‐2 protein (by 68 ± 4%, P < 0.0001) levels were observed in shSPINT2 cells when compared with shControl cells (Figure A,B). These reduced SPINT2/HAI‐2 levels are similar with the decreased SPINT2/HAI‐2 mRNA expression levels observed in MDS patients when compared with healthy donors (around 61%) …”

“…As we previously observed a significantly decreased expression of SPINT2 mRNA in MDS‐BMMSC compared to HD‐BMMSC, we evaluated SPINT2 mRNA and HAI‐2 expression in 1 HD‐BMMSC, 1 MDS‐BMMSC (1 low‐risk MDS‐BMMSC and 1 high‐risk MDS‐BMMSC), and 1 de novo AML‐BMMSC, representative sample from each group, after treatment with a demethylating agent, AZA. We initially used HS‐5 cell line as model and treated HS‐5 cell line with AZA or trichostatin.…”

“…Pereira and colleagues hypothesized that SPINT2/HAI‐2 is involved in prostate cancer tumourigenesis probably by regulation of SPINT2/HAI‐2 . We previously reported that the expression of SPINT2 mRNA is significantly lower in bone marrow mesenchymal stromal cell (BMMSC) from MDS patients compared to healthy donors (HD), which could be related with increased HGF and CXCL‐12 secretion …”

A Molecular Classification of Human Mesenchymal Stromal Cells

“…Other members of our network that have been previously described in human or mouse MSC biology, and used to prospectively isolate cells or have been validated at the protein level include PDGFRβ (Koide et al, 2007), SPINT2 (Roversi et al, 2014), CCDC80 (Charbord et al, 2015), FAP (Bae et al, 2008), BGN (Holley et al, 2015),and TM4SF1 (Bae et al, 2011). SPINT2 is a serine protease inhibitor whose activity is required in bone-marrow MSC, and its loss alters hematopoietic stem cell function in myelo-dysplastic disorders (Roversi et al, 2014).…”

“…SPINT2 is a serine protease inhibitor whose activity is required in bone-marrow MSC, and its loss alters hematopoietic stem cell function in myelo-dysplastic disorders (Roversi et al, 2014). In mice, CCDC80 is also necessary for reconstitution of bone marrow and support of haematopoiesis (Charbord et al, 2015).…”