Patient-specific 3D microfluidic tissue model for multiple myeloma.

In vitro culturing of primary multiple myeloma cells (MMC) has been a major challenge as this plasma cell malignancy depends on the bone marrow environment for its survival. Using a microfluidic platform to emulate the dynamic physiology of the bone marrow microenvironment, we report here a new approach for culturing difficult to preserve primary human MMC. The system uses a three-dimensional ossified tissue to mimic the tumor niche and recapitulate interactions between bone marrow cells and osteoblasts (OSB). To this end, the human fetal OSB cell line hFOB 1.19 was cultured in an eight-chamber microfluidic culture device to facilitate the seeding of mononuclear cells from bone marrow aspirates from three multiple myeloma patients. Optical microscopy, used for real-time monitoring of mononuclear cell interactions with the ossified tissue, confirmed that these are drawn toward the OSB layer. After 3 weeks, cocultures were characterized by flow cytometry to evaluate the amount of expansion of primary MMC (with CD138(+) and CD38(+)CD56(+) phenotypes) in this system. For each of the three patients analyzed, bone marrow mononuclear cells underwent, on an average, 2 to 5 expansions; CD38(+)CD56(+) cells underwent 1 to 3 expansions and CD138(+) cells underwent 2.5 to 4.6 expansions. This approach is expected to provide a new avenue that can facilitate: (1) testing of personalized therapeutics for multiple myeloma patients; (2) evaluation of new drugs without the need for costly animal models; and (3) studying the biology of multiple myeloma, and in particular, the mechanisms responsible for drug resistance and relapse.