Targeting mesenchymal stromal cells plasticity to reroute acute myeloid leukemia course. Targeting mesenchymal stromal cells plasticity to reroute acute myeloid leukemia course

MSC and AML dual targeting to treat pediatric AML Bone marrow (BM) microenvironment supports 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 severely compromised 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 cell (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 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 AML cells endow h-MSCs with a pro-oncogenic transcriptional profile and functions similar to the AML-MSCs when co-cultured in vitro. 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 sustained AML blasts altering MSC cell activities in the BM niche in order to favor disease development and progression, becoming a pharmacological target. We discovered that a novel AML-MSCs selective CaV1.2 channel blocker drug, Lercanidipine, is able to impair leukemia progression in 3D 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. Overall design: Gene expression was measured using Affymetrix platform in 21 MSCs derived from bone marrow of pediatric AML patients at diagnosis

双靶向MSC与AML治疗儿童急性髓系白血病：骨髓（Bone Marrow，BM）微环境通过自我更新与分化进程、细胞间相互作用及细胞因子分泌的精细平衡，调控正常造血功能；而在白血病发生过程中，该平衡会被严重破坏，转而促进肿瘤细胞增殖。对于儿童急性髓系白血病（Acute Myeloid Leukemia，AML）而言，化疗仍是标准治疗方案，但仍有超过30%的患者会出现复发。为加快创新药物的研发评估进程，本研究旨在探究间充质基质细胞（Mesenchymal Stromal Cell，MSC）在白血病龛中的作用，以明确其在白血病细胞免疫逃逸机制中的贡献。我们利用源自患者的AML细胞与间充质基质细胞（AML-MSCs）或健康供体来源的间充质基质细胞，构建了人源化三维（three-dimensional，3D）白血病龛模型。研究发现，AML细胞可与间充质基质细胞建立物理连接，介导转录组重编程，诱导异常细胞增殖与分化，并严重削弱间充质基质细胞的免疫调节能力。体外共培养实验证实，AML细胞可赋予人源间充质基质细胞（human MSCs，h-MSCs）致瘤转录谱与功能表型，使其与AML-MSCs趋于一致。相反，取自疾病缓解期患者骨髓的间充质基质细胞，其转录组与功能水平均恢复至健康状态，包括分泌组特征也得以修复。我们证实，骨髓龛中间充质基质细胞的活性改变可维持AML母细胞存活，进而促进疾病发生与进展，因此间充质基质细胞可作为药物干预靶点。本研究发现，一种新型选择性靶向AML-MSCs的CaV1.2通道阻滞剂——乐卡地平（Lercanidipine），若与化疗联合使用，可在体外三维模型及体内移植模型中均抑制白血病进展，这一结果支持“双靶向策略可产生协同效应”的假说。实验整体设计：本研究采用Affymetrix芯片平台，对21例初诊儿童AML患者骨髓来源的间充质基质细胞进行基因表达检测。