Multiple myeloma (MM) is a neoplasia of bone marrow (BM) plasma cells that remains largely incurable with current treatment. Advancing therapeutic discoveries has been hampered by the lack of genetically heterogeneous models of MM. To circumvent this limitation, we engineered fifteen mouse models carrying combinations of eight MM genetic drivers, which fulfilled the pathogenesis of human disease including progression from premalignant states under immune surveillance. Integrative analyses of ⁓500 mice and ⁓1,000 patients revealed a MAPK-MYC genetic pathway that regulates time to progression and immune escape mechanisms across genetically heterogeneous tumors. During progression, MYC-dependent and independent remodeling of the BM microenvironment divided MM into immune categories with predominance of selected T-cell subpopulations, which dictated immunotherapy responses. Experimental targeting of the cytotoxic or immunosuppressive T-cell states observed in refractory MM patients enhanced immunotherapy effectiveness. Our resource enabled characterization of MM cell-intrinsic and immunological traits at unprecedented levels, which will accelerate the translation of personalized immunotherapy.
Overall design: scRNA-seq + scTCR-seq were performed in 13 bone marrow aspirates from 2 healthy (Ycɣ1), 3 MGUS (BIcɣ1), 3 MM (BIcɣ1), 3 MGUS (MIC) and 2 MM (MIC) bearing mice. Cells were FACS sorted (a mix of 0.8x10^5 T cells + 0.8x10^5 NK cells + 0.25x10^5 monocytes + 0.15x10^5 B cells) in 100 µL of PBS+0.05% BSA. Samples with at least 90% viability were processed using the 10X Genomics (CA, USA) scRNA/TCRseq kit, following the manufacturer’s instructions (Chromium Next GEM Single Cell V(D)J v1.1 protocol rev F for human samples and Chromium Next GEM Single Cell 5’ v2 Dual Index protocol rev B for mice samples). Quality control was performed with Qubit Fluorometric Quantification (ThermoFisher Scientific, MA, USA) using the double-stranded DNA high-sensitivity assay kit, and with TapeStation (Agilent, Santa Clara, CA) using high-sensitivity screentapes. Libraries were sequenced on a NextSeq 550 (Illumina, San Diego, CA).
WES was performed in 71 BM samples isolated from GFP+ CD138+B220− PCs (purity, >99%), including 62 samples from the MM stage, 3 samples of pooled PCs from nine mice at the MGUS stage (3 mice with similar genotype were included on each pooled sample), and 6 samples from MM-derived cell lines. As MM reference controls, 5TGM1 and 12598Vk*Myc cell lines were also characterized.
Less...