Impact of the BCR structure on CLL drug resistance
The B-cell receptor (BCR) is a vital structure for the development and homeostasis of normal B-lymphocytes, playing an important role in the life of neoplastic B cells. About a third of CLL patients carry BCR with quasi-identical IG sequences, also referred to as stereotyped BCR (Agathangelidis A et al., Blood 2012). Patients expressing the same stereotyped BCR often share similar genomic aberrations and clinical course of the disease. Here, we propose to better understand the impact of the BCR structure on CLL drug resistance through 2 main approaches: (a) characterization of CLL IG repertoire using next generation sequencing (NGS). Within a European collaborative project (www.euroclonality.org), we will use a molecular barcoding strategy; improve our bioinformatics pipeline by introducing Big data-derived algorithmic approaches (collaboration with Dr Bernardes, Lab of Computational and Quantitative Biology, UMR 7238, UPMC); and develop graphic vizualization tools (collaboration with M Giraud, INRIA & CNRS, Lille). With this, we will be able to fully appreciate the clonal architecture of the CLL cells at the IG loci level and we will analyze its evolution during disease progression; (b) Impact of BCR antigen-binding specificity on leukemic cells behavior. We postulate that editing the IG variable region should alter the cellular response following BCR engagement. We will therefore use the CRISPR/Cas9 technology to edit the native IG variable region of CLL cell lines with those derived from stereotypic BCR CLL cases having opposite clinical behavior (indolent vs aggressive). These isogenic variants will be evaluated for their response to BCR stimulation.