Targeting mesenchymal stromal cells plasticity to reroute acute myeloid leukemia course

Abstract

Bone marrow (BM) microenvironment contributes to the regulation of normal hematopoiesis through a finely tuned balance of self-renewal and differentiation processes, cell-cell interaction and secretion of cytokines that during leukemogenesis are altered and favor tumor cell growth. In pediatric acute myeloid leukemia (AML), chemotherapy is the standard of care, but still >30% of patients relapse. The need to accelerate the evaluation of innovative medicines prompted us to investigate the mesenchymal stromal cells (MSCs) role in the leukemic niche to define its contribution to the mechanisms of leukemia escape. We generated humanized three-dimensional (3D) niche with AML cells and MSCs derived from either patients (AML-MSCs) or healthy donors. We observed that AML cells establish physical connections with MSCs, mediating a reprogrammed transcriptome inducing aberrant cell proliferation and differentiation, and severely compromising their immunomodulatory capability. We confirmed that AML cells modulate h-MSCs transcriptional profile promoting functions similar to the AML-MSCs when co-cultured in vitro, thus facilitating leukemia progression. Conversely, MSCs derived from BM of patients at time of disease remission showed recovered healthy features, at transcriptional and functional levels, including the secretome. We proved that AML blasts alter MSCs activities in the BM niche, favoring disease development and progression. We discovered that a novel AML-MSCs selective CaV1.2 channel blocker drug, Lercanidipine, is able to impair leukemia progression in 3D niche both in vitro and when implanted in vivo, if used in combination with chemotherapy, supporting the hypothesis that synergistic effects can be obtained by dual targeting approaches.

Novel Compounds Synergize With Venetoclax to Target KMT2A-Rearranged Pediatric Acute Myeloid Leukemia

“…AML patients (namely, AML-MSCs) into a scaffold that resembles the composition and structure of the bone trabecules of the niche. In this 3D system, we described interactions between leukemic cells and stromal cells which play a critical role in AML proliferation and drug response (Borella et al, 2021). Therefore, we validated novel selected drug combinations in this setting, either with cell lines or primary samples, confirming a significant improvement mediated by combined treatments in reducing leukemia burden.…”

“…The AML-MSC isolation and culture, 3D scaffold specifications, and 3D culturing setup were previously described (Borella et al, 2021). Briefly, AML-MSCs were seeded in the scaffold and cultured in StemMACSTM MSC Expansion Media (Miltenyi Biotec) for MSC expansion for 5 days.…”

“…To validate our results, we took advantage of an innovative threedimensional (3D) culture model that we recently developed; it consists of a 3D biomimetic scaffold made of hydroxyapatite/ collagen (70/30%) (Tampieri et al, 2008) that allowed long-term AML co-culture with mesenchymal stromal cells (MSCs) derived from the bone marrow (BM) of leukemia patients at diagnosis of de novo AML (namely, AML-MSCs), recapitulating the crucial physiological aspects of leukemia niche (Borella et al, 2021). This 3D system was demonstrated to be a bona fide model, wherein robust and reliable drug screening is performed due to the recapitulation of the BM microenvironment.…”

Dynamic Changes of the Bone Marrow Niche: Mesenchymal Stromal Cells and Their Progeny During Aging and Leukemia

“…Using a holistic view, recent bioengineering advances were made in recreating in situ BM stroma through organ-on-achip devices that would allow to investigate MSC-mediated chemo-resistance mechanisms and assess therapy efficacy of new anti-tumor compounds (reviewed in Santos Rosalem et al, 2020). Similar approaches using biomimetic scaffolds capable of mimicking bone extracellular-matrix were also used to study MSC transcriptional and immunomodulatory alterations by MDS/AML blast cells (Abarrategi et al, 2017;Mian et al, 2021) and allowed recently for the discovery of a novel AML-MSCs selective CaV1.2 channel blocker drug, Lercanidipine, that is able to impair leukemia progression when administered in vivo (Borella et al, 2021). Collectively, although promising targets and drugs are currently further characterized toward translational applications, a careful development of MSC-based cell therapies will be primordial to boost ant-cancer properties while eliminating tumor-promoting effects.…”

Genomic Abnormalities as Biomarkers and Therapeutic Targets in Acute Myeloid Leukemia

“…Because of the small number of AML LSCs which can be enriched, and the requirement for a 200-1000-fold incrase of the library complex, a library with the smallest but most relevant shRNAs or guide RNAs (gRNAs) will be required for optimization of the screen. To mimic the bone marrow microenvironment, a standardised three-dimensional culture containing mesenchymal stromal cells and other components of the bone marrow niche [166][167][168] must be developed and optimised to standardise the screen across different samples. CRISPR technology has grown rapidly within the last decade and has become the mainstream technique for functional genomics screens.…”