Abstract
Our group has recently shown that proliferating mesenchymal cells (MC), obtained from BAL of BOS patients, express CD44 and that this expression correlates with mTOR expression and with in vitro proliferative rate. By these results we have designed an innovative approach based on biocompatible nanoparticles loaded with the mTOR inhibitor everolimus and functionalized with anti CD44 MoAb, for the selective targeting to the specific cells (targNP). Fluorescent labeled targNP have been used to assess cell uptake by confocal microscopy. Cell apoptosis/death (annexin V/7AAD) and proliferation (CFSE) were evaluated by flow cytometry. We used primary MC isolated from 2 BOS patients (grade 1 and 2) with the following phenotype: BOS 1: 85% CD90+ of which 33% co-expressing CD9; BOS2: 93% CD90+ with 38% co-expressing CD146, 25% CD9, and 38% both CD146 and CD9. Both MC samples were negative for CD45RO and CD34 and positive for CD44 (98%). TargNP were shown to adhere to membrane within 15 min and completely enter into the cells after 45 min. Drug free nanoparticles, as control, were completely inert. TargNP treated cells showed a significantly higher mean rate of annexin V at 8 h (17,4 versus 4,5%) and 24 h (42,15 versus 5,3%) respect to control cells while mean 7AAD expression at 24 h was 4,1 versus 1.3%. Likewise, cell proliferation was significantly inhibited at 24 and 48 h (mean: 41 and 37.2%, respectively). This is, by far, the first proof of concept that an innovative approach based on drug coated NP can be used to selectively address MC which proliferate in the airways. Further in vitro and in vivo studies will investigate possible efficacy of this new treatment strategy.
- © 2012 ERS
