Cxcl11

Peripheral blood mononuclear cells (PBMC) were isolated using a Ficoll density gradient centrifugation; only samples containing more than 70% CLL cells in PBMC were chosen for the assay. Transmigration of CLL cells was assessed using polycarbonate Transwell inserts with 5-μm pore size (Corning Costar). Briefly, the cells at 1 × 10exp 6/mL were applied to the upper chamber in RPMI-1640 containing 1% bovine serum albumin (BSA) in the presence or absence of CXCL11 (BioLegend). Filters were transferred into the lower wells containing RPMI-1640 with 1% BSA in the presence or absence of CXCL12 (BioLegend). After 3 hours at 37°C in 5% CO₂, cells that migrated into the lower chambers were counted and analysed for CXCR3 and CXCR4 expression on BD FACSCanto II.

Murine C2C12 myoblasts (CRL-1772, ATCC) were cultured in DMEM (Lonza; Basel, Switzerland) supplemented with 10% fetal calf serum (FCS; Gibco^®Invitrogen, Carlsbad, CA). For induction of differentiation into myotubes, subconfluent cultures were switched to DMEM containing 1% FCS. C2C12 myotubes were treated with either CXCL11 (100 ng/ml; BioLegend, San Diego, CA) or CXCL12 (100 ng/ml; Almac, East Lothian, Scotland) as specified in the text. At the indicated times, cultures were either processed for Western blot analysis as described below or fixed with 4% paraformaldehyde for subsequent immunolabelling.