基于干性相关基因表达特征的白血病干细胞 (LSC) 评分 LSC-17 是急性髓系白血病 (AML) 疾病预后不良的指标。然而，我们对LSC和白血病前期细胞之间关系的理解仍然不完整。特别是，目前尚不清楚白血病前细胞的“生态位锚定”是否影响疾病的演变。为了解决这个问题，我们在诱导型 iMLL-AF9 驱动的 AML 小鼠模型中条件性地灭活了造血干细胞 (HSC) 和 LSC 表达的粘附分子 JAM-C。在诱导白血病起始 iMLL-AF9 融合之前删除 Jam3（编码 JAM-C）会导致 HSC 扩增从长期向短期转变，但不会影响疾病的发生和进展。体外实验表明，无论使用何种骨髓基质细胞，JAM-C 都能控制白血病细胞的筑巢。对从患病小鼠中分离出的白血病 HSC 进行的 RNA 测序显示，Jam3 缺陷动物中上调的基因属于激活蛋白-1 (AP-1) 和 TNF-α/NFβ 途径。失调基因的人类直系同源物可以根据 AP-1/TNF-a 基因表达来识别评分，该评分与 LSC-17 评分不同且互补。具有 LSC-17 和 AP-1/TNF-α 基因特征的 AML 患者的亚分层定义了四组，中位生存期范围从低于一年到 8 年后未达到中位生存期。最后，共培养实验表明白血病细胞中的 AP-1 激活取决于基质细胞的性质。总而言之，我们的结果确定 AP-1/TNF-α 基因特征作为 LSC 锚定在特定骨髓生态位的代表，从而提高了 LSC-17 评分的预后价值。 NCT02320656.版权所有 © 2024 美国血液学会。

The leukemic stem cell (LSC) score LSC-17 based on a stemness-related gene expression signature is an indicator of poor disease outcome in acute myeloid leukemia (AML). However, our understanding of the relationships between LSC and pre-leukemic cells is still incomplete. In particular, it is not known whether "niche-anchoring" of pre-leukemic cell affects disease evolution. To address this issue, we conditionally inactivated the adhesion molecule JAM-C expressed by haematopoietic stem cells (HSC) and LSC in an inducible iMLL-AF9-driven AML mouse model. Deletion of Jam3 (encoding JAM-C) before induction of the leukemia-initiating iMLL-AF9 fusion resulted in a shift from long term to short term-HSC expansion, without affecting disease initiation and progression. In vitro experiments showed that JAM-C controlled leukemic cell nesting irrespective of the bone marrow stromal cells used. RNA sequencing performed on leukemic HSC isolated from diseased mice revealed that genes upregulated in Jam3-deficient animals belonged to Activation Protein-1 (AP-1) and TNF-/NFB pathways. Human orthologs of dysregulated genes allowed to identify a score based on AP-1/TNF-a gene expression that was distinct and complementary from LSC-17 score. Sub-stratification of AML patients with LSC-17 and AP-1/TNF-genes signature defined four groups with median survival ranging from below one year to a median not reached after 8 years. Finally, coculture experiments showed that AP-1 activation in leukemic cells was dependent on the nature of stromal cells. Altogether, our results identify the AP-1/TNF- gene signature as a proxy of LSC anchoring in specific bone marrow niches which improves the prognosis value of the LSC-17 score. NCT02320656.Copyright © 2024 American Society of Hematology.