CYR61 prevents bone loss and reduces tumor burden in the SCID-hu mouse model. In the first experiment (A-C), CD138-selected primary MMPCs from 3 patients were injected (100 000/mouse) into implanted bones in SCID-hu mice and were treated with recombinant CCN1. Pretreatment (CONT) and post-CCN1 treatment (CCN1) groups were compared. In the second set of experiments (D-F; 10 mice/group) and (G-J; 8 mice/group), H929 cells transduced with empty vector (EV), CYR61 complementary DNA (CYR61) or CYR61 with mutated α_vβ₃-binding domain (D125A) were injected (100 000 cells/mouse) into implanted bones in SCID-hu mice. (A,D,G) Change in BMD of the myelomatous bones from preengraftment levels (B,J) Radiographs of human bones implanted in SCID-hu mice before start of therapy (column 1) and at the end of the study (column 2) for each treatment group. (C,F,I) Serum hIg was quantitated by ELISA as a measure of tumor growth. (E,H) Numbers of osteoblasts (positive for osteocalcin staining) and osteoclasts (positive for TRAP staining).