Cross center single-cell RNA sequencing study of the immune microenvironment in rapid progressing multiple myeloma

Abstract

Despite advancements in understanding the pathophysiology of Multiple Myeloma (MM), the cause of rapid progressing disease in a subset of patients is still unclear. MM’s progression is facilitated by complex interactions with the surrounding bone marrow (BM) cells, forming a microenvironment that supports tumor growth and drug resistance. Understanding the immune microenvironment is key to identifying factors that promote rapid progression of MM. To accomplish this, we performed a multi-center single-cell RNA sequencing (scRNA-seq) study on 102,207 cells from 48 CD138- BM samples collected at the time of disease diagnosis from 18 patients with either rapid progressing (progression-free survival (PFS) < 18 months) or non-progressing (PFS > 4 years) disease. Comparative analysis of data from three centers demonstrated similar transcriptome profiles and cell type distributions, indicating subtle technical variation in scRNA-seq, opening avenues for an expanded multicenter trial. Rapid progressors depicted significantly higher enrichment of GZMK+ and TIGIT+ exhausted CD8+ T-cells (P = 0.022) along with decreased expression of cytolytic markers (PRF1, GZMB, GNLY). We also observed a significantly higher enrichment of M2 tolerogenic macrophages in rapid progressors and activation of pro-proliferative signaling pathways, such as BAFF, CCL, and IL16. On the other hand, non-progressive patients depicted higher enrichment for immature B Cells (i.e., Pre/Pro B cells), with elevated expression for markers of B cell development (IGLL1, SOX4, DNTT). This multi-center study identifies the enrichment of various pro-tumorigenic cell populations and pathways in those with rapid progressing disease and further validates the robustness of scRNA-seq data generated at different study centers.

CAR-T cell therapy in multiple myeloma: Current limitations and potential strategies

“…In turn, MM cells produce IL-6 and RANKL, which could enhance bone resorption activity of OCs. In MM patients, TAMs which display M2-like properties apparently infiltrate the bone marrow and exhibit robust activation of BAFF pro-proliferative signaling ( 85 ), and they are involved in promoting angiogenesis and tumor resistance ( 86 , 87 ). In addition, massive MDSCs were accumulated in bone marrow microenvironment of MM patients ( 88 ).…”

“…Moreover, MM microenvironment, including MM cells, immunosuppressive cells, and BMSCs, as well as multiple soluble cytokines, interact with CAR-T cells, which could result in CAR-T cell dysfunction and inhibit engraftment of CAR-T cells, eventually promoting extrinsic resistance of MM cells after CAR-T cell infusion ( 85 , 93 , 98 ) ( Figure 3 ). On the one hand, tumor cells and immunosuppressive cells in bone marrow microenvironment induce CAR-T cell exhaustion through direct cell-to-cell contact, such as PD-1/PDL-1 pathway and Fas/FasL pathway.…”

An IL-1β driven neutrophil-stromal cell axis fosters a BAFF-rich microenvironment in multiple myeloma

“…BCMA is ubiquitously expressed by myeloma cells 25 and ligation with BAFF increases growth of myeloma cells in culture 26 (Supplemental Figure 2E). Increased transcription of TNFSF13B in MM bone marrow is also associated with rapid disease progression 27 .…”

“…The TNF family member BAFF is a ligand for myeloma-cell expressed BCMA 25, 26 , a receptor involved in proliferation and survival of primary myeloma cells and myeloma cell lines in vitro 34, 43 . BAFF is a strong contributor to disease burden in myeloma mouse models 44 , and associated with rapid progression in patients 27 . Serum levels of BAFF are inversely correlated with MM patient survival 33 , signifying the importance of this growth factor in myeloma pathobiology.…”

The Immune Microenvironment in Multiple Myeloma Progression at a Single-cell Level

“…Single‐cell sequencing technologies that have emerged over the last years have the potential to significantly advance the field because they enable the evaluation of alterations in cell numbers and states as well as interactions between MM cells and the BM‐ME. Recent studies have applied single‐cell techniques at different precursor and MM stages to determine the comprehensive changes in the BM‐ME and to identify mechanisms that foster oncogenesis 4–11 . This article briefly summarizes these studies and proposes how the dissection of the BM‐ME on a single‐cell level can improve our understanding of MM pathogenesis, thereby advancing prognostication and the therapeutic landscape.…”