Halofuginone inhibits phosphorylation of SMAD-2 reducing angiogenesis and leukemia burden in an acute promyelocytic leukemia mouse model.

Patricia A Assis,Ana Silvia G Lima,Eduardo M Rego,Arnon Nagler,Fernando Chahud,Aglair B Garcia,Roberto P Falcão,Lorena L De Figueiredo-Pontes,Carolina T Pintão,Larissa A Cândido,Vitor Leão,Rodrigo A Panepucci,Fabiano P Saggioro

doi:10.1186/s13046-015-0181-2

Abstract

BackgroundHalofuginone (HF) is a low-molecular-weight alkaloid that has been demonstrated to interfere with Metalloproteinase-2 (MMP-2) and Tumor Growth Factor-β (TGF-β) function and, to present antiangiogenic, antiproliferative and proapoptotic properties in several solid tumor models. Based on the fact that high levels of Vascular Endothelial Growth Factor (VEGF) and increased angiogenesis have been described in acute myeloid leukemia and associated with disease progression, we studied the in vivo effects of HF using an Acute Promyelocytic Leukemia (APL) mouse model.MethodsNOD/SCID mice were transplanted with leukemic cells from hCG-PML/RARA transgenic mice (TM) and treated with HF 150 μg/kg/day for 21 days. The leukemic infiltration and the percentage of VEGF+ cells were evaluated by morphology and flow cytometry. The effect of HF on the gene expression of several pro- and antiangiogenic factors, phosphorylation of SMAD2 and VEGF secretion was assessed in vitro using NB4 and HUVEC cells.ResultsHF treatment resulted in hematological remission with decreased accumulation of immature cell and lower amounts of VEGF in BM of leukemic mice. In vitro, HF modulated gene expression of several pro- and antiangiogenic factors, reduced VEGF secretion and phosphorylation of SMAD2, blocking TGF-β-signaling.ConclusionTaken together, our results demonstrate that HF inhibits SMAD2 signaling and reduces leukemia growth and angiogenesis.Electronic supplementary materialThe online version of this article (doi:10.1186/s13046-015-0181-2) contains supplementary material, which is available to authorized users.

Highlights

Halofuginone (HF) is a low-molecular-weight alkaloid that has been demonstrated to interfere with Metalloproteinase-2 (MMP-2) and Tumor Growth Factor-β (TGF-β) function and, to present antiangiogenic, antiproliferative and proapoptotic properties in several solid tumor models
In Acute Promyelocytic Leukemia (APL) the TGF-β pathway is deregulated by the cytoplasmic PML isoform [26] and we have demonstrated that HF inhibited cell proliferation and induced apoptosis in the APL cell line NB4 through modulation of TGF-β-target genes, such as c-Myc and p21 [1]
Angiogenesis is aberrantly increased in the APL transgenic mouse model Based on the demonstration of high levels of Vascular Endothelial Growth Factor (VEGF) in bone marrow (BM) biopsies from APL patients [15], we first investigated

Summary

Introduction

Halofuginone (HF) is a low-molecular-weight alkaloid that has been demonstrated to interfere with Metalloproteinase-2 (MMP-2) and Tumor Growth Factor-β (TGF-β) function and, to present antiangiogenic, antiproliferative and proapoptotic properties in several solid tumor models. Based on the fact that high levels of Vascular Endothelial Growth Factor (VEGF) and increased angiogenesis have been described in acute myeloid leukemia and associated with disease progression, we studied the in vivo effects of HF using an Acute Promyelocytic Leukemia (APL) mouse model. After standard treatment with ATRA (all-trans retinoic acid), VEGF levels and BM MVD were normalized Another clinical study with 17 new cases of APL associated the efficacy of the arsenic trioxide treatment with its antiangiogenic effect, demonstrated by the reduced MVD in the BM and increased survival [16]

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Discussion

Conclusion