A unique three-dimensional model for evaluating the impact of therapy on multiple myeloma

Abstract

IntroductionHematopoiesis in bone marrow (BM) occurs in distinct microenvironmental niches. Discrete extracellular matrix (ECM) microenvironments within the BM help to separate endosteum, an interface between bone and BM, from the central marrow. Methods for studying hematopoiesis include clonal culture systems in semisolid media, 1 short-term 2 and long-term 3,4 liquid cultures, and tissue culture systems where hematopoietic cells grow on feeder layers of BM stromal cells. 5,6 However, cell culture systems involving growth on the surface of tissue culture plastic do not accurately represent tissue architecture 7 or the complex interactions between cells and their micro-environment. Recently, a stromal spheroid coculture model 8 and various scaffolds 9,10 have been developed to recreate the three-dimensional (3-D) environment of the BM, but these models fail to recapitulate the physiologic conditions of the BM. To adequately study B-cell development, 11 pathogenesis, 12,13 and neoplasia, 14 a culture system that places BM cells within their physiologic environment is required. For BM-localized malignancies, more effective culture systems must incorporate all compartments of the malignant clone, including cancer stem and progenitor cells, to identify their therapeutic vulnerabilities.Multiple myeloma (MM), an incurable cancer with 3-to 5-year survival despite the development of potent new therapies, 15 is characterized by monoclonal immunoglobulin (Ig), lytic bone lesions, 16 Here we present a robust 3-D tissue culture model in which the human BM microenvironment is reconstructed in vitro. In 3-D, the MM clone expands within its native microenvironment providing a valuable preclinical model within which conventional (melphalan) and novel (bortezomib) therapeutics selectively kill their target cells. In 3-D cultures, nonproliferating cells from MM BM concentrate at a reconstructed endosteummarrow junction (rEnd). Purified nonproliferating MM BM cells include MM-CSCs, as defined by their ability in a secondary culture to generate B/PC progeny harboring the unique MM clonotypic signature. Three-dimensional cultures of BM or mobilized blood autografts (MBAs) offer a preclinical model within which new therapies can be tested for their impact on all compartments of the MM clone, as well as providing access to the MM-CSC that underlie disease progression. An Inside Blood analysis of this article appears at the front of this issue.The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked ''advertisement'' in accordance with 18 USC section 1734. For personal use only. on May 8, 2018. by guest www.bloodjournal.org From Methods MaterialsAfter approval from the Health Research Board (University of Alberta) and the Alberta Cancer Board, and after informed consent was obtained in accordance with the Declaration of Helsinki, BM samples (n ϭ 48) were provided from patients undergoing BM biopsies at the Cross Cancer Institute. Al...

Anti-CD47 antibodies promote phagocytosis and inhibit the growth of human myeloma cells

“…Anti-CD47 antibodies inhibited myeloma growth in the presence of a human bone marrow microenvironment The bone marrow microenvironment supports the survival and proliferation of myeloma cells. 2 To determine whether anti-CD47 antibodies also inhibit myeloma growth in the presence of human bone marrow microenvironment, we grafted human fetal bone fragments into immunocompromised mice and directly transplanted patient-derived myeloma cells into the bone grafts. After detecting human immunoglobulin in mouse sera, we treated mice daily with anti-CD47 (B6H12) antibody or PBS for 4 weeks (Figure 4a).…”

“…[1][2][3] Current myeloma therapies such as hematopoietic cell transplantation and combinatorial chemotherapies are rarely curative and relapse is common. 4 This implies that therapy-resistant myeloma-initiating cells exist and that new therapeutics must be developed to target and eradicate these myeloma-initiating cells.…”

Newly established myeloma-derived stromal cell line MSP-1 supports multiple myeloma proliferation, migration, and adhesion and induces drug resistance more than normal-derived stroma

“…Several models have illustrated the superior ability of 3D cultures to recreate the BM microenvironment and promote MM cell growth compared to classic 2D cultures. 13,20,21 We have recently shown that a novel 3DTEBM model based on fibrinogen naturally found in the BM supernatant of MM patients recapitulated the pathophysiological environment of MM, recreated the interactions of MM cells with their microenvironment more accurately, allowed the progression of primary patient samples and showed significantly higher resistance to proteasome inhibitors (PIs) compared Figure 1C) or quintuplicates (Figure 1Bi, Figure 1Biii) and each experiment was repeated 3 times. Results are shown as mean ± standard deviation and analyzed using two-way ANOVA for statistical significance, and were considered significantly different for P value less than 0.05.…”

CD138-negative clonogenic cells are plasma cells but not B cells in some multiple myeloma patients

“…In a later study utilizing methylcellulose media supplemented with lymphocyte conditioned media as growth factors, clonogenic MM progenitor cells were found in BM cells lacking expression of the plasma cell marker CD138. [11][12][13][14][15] It was further reported that rituximab inhibited MM colony formation 11 and that CD20 þ B cells from some MM patients could produce MM plasma cells in a 3-D culture in vitro, 16 which suggests that CD138…”