Dysregulation of miRNAs In AL Amyloidosis

Abstract 4648

Bone marrow plasma cells (BMPC) were purified from aspirates obtained from patients with AL amyloidosis using anti-CD138 immunomagnetic beads, and from controls. Expression levels of micro RNAs (miRNAs) were compared by microarray. The levels of ten miRNAs were found to be increased more than 1.5-fold in BMPC of AL amyloidosis patients. These results were confirmed using stem-loop RT-qPCR for miR-148a, miR-26a, and miR-16, the most highly upregulated miRNAs in the AL samples. miR-16, a micro RNA linked to other hematopoietic diseases, was significantly increased in the AL group at baseline and also in treated patients with persistent monoclonal plasma cells in the bone marrow, but not in patients who achieved a hematologic remission after therapy and normal polyclonal BMPCs. miR-16 can be derived from the miR-16-1/mirR-15a cluster on chromosome 13 or the miR-16-2/miR-15b cluster on chromosome 3. The expression of miR-15b was much higher than miR15a in AL and control BMPC samples; this suggests that miR-16 in plasma cells is mostly derived from chromosome 3. The anti-apoptosis gene BCL-2, a putative target mRNA that can be down-regulated by miR-16, was present in the BMPCs from the AL group despite the elevated levels of miR-16. Our data suggest that miRNAs are dysregulated in clonal plasma cells from AL amyloidosis patients and that abnormal levels of miRNAs may be potential biomarkers for disease.