NEOPLASIA Brief report A clinically relevant SCID-hu in vivo model of human multiple myeloma

We developed a novel in vivo multiple myeloma (MM) model by engrafting the interleukin 6 (IL-6)–dependent human MM cell line INA-6 into severe combined im-munodeficiency (SCID) mice previously given implants of a human fetal bone chip (SCID-hu mice). INA-6 cells require either exogenous human IL-6 (huIL-6) or bone marrow stromal cells (BMSCs) to prolifer-ate in vitro. In this model, we monitored the in vivo growth of INA-6 cells stably transduced with a green fluorescent pro-tein (GFP) gene (INA-6GFP cells). INA-6 MM cells engrafted in SCID-hu mice but not in SCID mice that had not been given implants of human fetal bone. The level of soluble human IL-6 receptor (shuIL-6R) in murine serum and fluorescence imaging of host animals were sensitive indicators of tumor growth. Dexamethasone as well as experimental drugs, such as Atiprimod and B-B4-DM1, were used to confirm the utility of the model for evaluation of anti-MM agents. We report that this model is highly reproducible and allows for evaluation of investigational drugs target-ing IL-6–dependent MM cells in the hu-man bone marrow (huBM) milieu. (Blood