Constitutive expression of MMPs in B-CLL. (A) Lysates from 2 × 106 fresh B-CLL cells from 5 different patients (P1-P5), peripheral blood B lymphocytes (PB-BL), or EBV-transformed normal B cells (Bro168, CO43, HUT112) were analyzed by gelatin zymography on 10% gels. MMP-9 was identified as the 92-kDa proactive form. Actin was analyzed in identical aliquots from the same lysates by Western blotting and used as control for protein loading. Quantitative values represent the average of 2 different samples for PB-BL and 12 different samples for B-CLL. Error bars indicate standard deviation. *** P < .001. (B) Flow cytometric analysis of MT1-MMP surface expression in B-CLL cells from one patient or NCI-H929 myeloma cells, without (Control) or with PMA (50 ng/mL, 24 hours). (C) RT-PCR analysis of constitutive MT1-MMP mRNA expression in B-CLL cells from patients 1 to 5. BLM melanoma cells were included as positive control. (D) Lysates from 4 different B-CLL samples or BLM cells were analyzed by Western blotting, and MT1-MMP was identified using the LEM2/15 mAb.
