Evidence of a role for CD44 and cell adhesion in mediating resistance to lenalidomide in multiple myeloma: therapeutic implications

Abstract

Resistance of myeloma to lenalidomide is an emerging clinical problem, and though it has been associated in part with activation of Wnt/β-catenin signaling, the mediators of this phenotype remained undefined. Lenalidomide-resistant models were found to overexpress the hyaluronan (HA)-binding protein CD44, a downstream Wnt/β-catenin transcriptional target. Consistent with a role of CD44 in cell adhesion-mediated drug-resistance (CAM-DR), lenalidomide-resistant myeloma cells were more adhesive to bone marrow stroma and HA-coated plates. Blockade of CD44 with monoclonal antibodies, free HA, or CD44 knockdown reduced adhesion and sensitized to lenalidomide. Wnt/β-catenin suppression by FH535 enhanced the activity of lenalidomide, as did interleukin-6 neutralization with siltuximab. Notably, all-trans-retinoic acid (ATRA) down-regulated total β-catenin, cell-surface and total CD44, reduced adhesion of lenalidomide-resistant myeloma cells, and enhanced the activity of lenalidomide in a lenalidomide-resistant in vivo murine xenograft model. Finally, ATRA sensitized primary myeloma samples from patients that had relapsed and/or refractory disease after lenalidomide therapy to this immunomodulatory agent ex vivo. Taken together, our findings support the hypotheses that CD44 and CAM-DR contribute to lenalidomide-resistance in multiple myeloma, that CD44 should be evaluated as a putative biomarker of sensitivity to lenalidomide, and that ATRA or other approaches that target CD44 may overcome clinical lenalidomide resistance.

The Nuclear Factor (Erythroid-derived 2)-like 2 and Proteasome Maturation Protein Axis Mediate Bortezomib Resistance in Multiple Myeloma

“…Viability Assays-Proliferation and viability assays with bortezomib (Selleck Chemical, Houston, TX) and all-trans-retinoic acid (ATRA) (Sigma) were performed as described previously (28). Briefly, cell lines or primary samples were treated with the indicated compound for a minimum of 24 h, unless otherwise indicated, followed by the addition of the tetrazolium reagent WST-1.…”

“…Immunoblotting-Cells were harvested and lysed in 1ϫ Lysis Buffer (Cell Signaling Technology, Danvers, MA), followed by resolution on gradient gels (Thermo Fisher Scientific, Carlsbad, CA), transferred to nitrocellulose (Bio-Rad), and probed with (28). Briefly, total RNA was isolated from cultured cells or tumor tissues using TRIzol (Thermo Fisher Scientific), and cDNA was synthesized using a High Capacity cDNA reverse transcription kit (Applied Biosystems, Foster City, CA).…”

Immunomodulatory drugs and their therapeutic effect in hematological malignancies through cereblon

“…Resistance of myeloma to lenalidomide is an emerging clinical problem, and though it has been associated in part with activation of Wnt/β-catenin signaling, the mediators of this phenotype remained undefined. Lenalidomide-resistant models were found to overexpress the hyaluronan (HA)-binding protein CD44, a downstream Wnt/β-catenin transcriptional target [72]. Consistent with a role of CD44 in cell adhesion-mediated drug resistance (CAM-DR), lenalidomideresistant myeloma cells were more adhesive to bone marrow stroma and HA-coated plates.…”

Identification of differently expressed genes in leukemia using multiple microarray datasets

“…CD44 is a negative cell surface marker of pluripotent stem cell identification during human fibroblast reprogramming (Quintanilla Jr. et al, 2014) and regulates endothelial cell proliferation and apoptosis by modulating CD31 and VE-cadherin expression (Tsuneki and Madri, 2014). A previous study suggested that CD44 contributed to lenalidomide resistance in multiple myeloma (Bjorklund et al, 2014). Overexpression of the CD44 membrane receptor results in tumor initiation, growth, and cancer stem cell-specific behavior (Shah et al, 2013).…”