NCI-41356, a promising molecule in idiopathic pulmonary fibrosis?

Abstract

Idiopathic pulmonary fibrosis (IPF) is a progressive irreversible and fatal lung disease. IPF is characterized by myofibroblasts proliferation, abnormal and massive extracellular matrix deposition and collagen accumulation. We have already shown that the heat shock protein HSPB5 has a positive role on lung fibrogenic processes mainly though activation of smads pathway. In addition, HSPB5 chaperones vascular endothelial growth factor (VEGF) which role in fibrosis remains controversial. NCI-41356 is a chemical compound inhibiting the interaction between HSPB5 and VEGF, and it was shown to decrease in vitro and in vivo growth of breast tumor and VEGF signaling pathway [1] . Our aim was to explore the effects of NCI-41356 on pulmonary fibrosis. First , we tested the inhibitory properties of NCI-41356 on HSPB5/VEGF binding (Nanotemper), and on HSPB5 chaperone function (anti-aggregation assay). In vivo , C57/Bl6 mice were injected intratracheally with bleomycin (BLM) to induce fibrosis and treated intravenously with NaCl or NCI-41356. Collagen accumulation was evaluated by Sircol and Sirius Red technics. In vitro, fibroblasts and epithelial cells and ex vivo mouse lung slices were treated with TGF-β1, VEGF or both in presence or absence of NCI-41356 and α-Smooth Muscle Actin (α-SMA) and collagen expression were evaluated. First, we showed that NCI-41356 inhibits HSPB5 chaperon activity without modifying its interaction with SMAD4 and Nanotemper experiment suggested that NCI-41356 inhibits HSPB5/VEGF interaction. In vivo , NCI-41356 decreased collagen accumulation (Sirius Red and Sircol). This has been confirmed on lung slices and fibroblastic cells (NIH-3T3) where NCI-41356 decreased collagen expression induced by TGF-β1. However, NCI-41356 did not affect in any experimental condition the expression of key markers of myofibroblast differentiation such as α-SMA . Finally, we showed that NCI-41356 decreases the pro-migratory effects of TGF-β1 on A549 epithelial cells. Our Results showed in vitro and in vivo that NCI-41356 reduced efficiently lung collagen synthesis and accumulation induced in pro-fibrotic conditions. Exploration of mechanical pathways induced by NCI-41356 in these effects remains to be explored.