未经证实:嵌合抗原受体(CAR)-T细胞疗法在治疗造血系统恶性肿瘤方面取得了前所未有的成功。然而,由于缺乏仅在AML母细胞和白血病干细胞(LSC)上表达而不在正常造血干细胞(HSC)上表达的理想细胞表面靶标,因此这种细胞疗法在治疗急性髓性白血病(AML)方面受到阻碍.
UNASSIGNED:我们检测到AML细胞系表面的CD70表达,原发性AML细胞,HSC,和外周血细胞,并使用包含基于人源化41D12的scFv和41BB-CD3ζ胞内信号传导结构域的构建体产生第二代CD70特异性CAR-T细胞。细胞毒性,细胞因子释放,和抗原刺激中的增殖,CD107a测定,和CFSE测定用于证明体外有效的抗白血病活性。建立Molm-13异种移植小鼠模型以评估CD70CAR-T的体内抗白血病活性。探索CFU测定以评估CD70CAR-T在HSC上的安全性。
未经证实:CD70在AML原代细胞上异质表达,包括白血病,白血病祖细胞,和干细胞,但在正常HSC和大多数血细胞中不表达。抗CD70CAR-T细胞表现出强大的细胞毒性,细胞因子的产生,和与CD70+AML细胞系孵育时的增殖。它还在Molm-13异种移植小鼠模型中显示出强大的抗白血病活性和延长的存活时间。然而,这种CAR-T细胞疗法不能在体内完全消除白血病.
UNASSIGNED:我们的研究表明,抗CD70CAR-T细胞是AML的一种新的潜在治疗方法。然而,这种CAR-T细胞疗法并不能完全消除体内白血病,这表明,为了优化CAR-T细胞对AML的反应,未来的研究将需要旨在产生创新的组合CAR构建体或增加白血病细胞表面CD70表达密度,以延长循环中CAR-T细胞的寿命.
Chimeric antigen receptor (CAR)-T cell therapy has achieved unprecedented success in treating hematopoietic malignancies. However, this cell therapy is hampered in treating acute myeloid leukemia (AML) due to lack of ideal cell surface targets that only express on AML blasts and leukemia stem cells (LSCs) but not on normal hematopoietic stem cells (HSCs).
We detected the CD70 expression on the surfaces of AML cell lines, primary AML cells, HSC, and peripheral blood cells and generated a second-generation CD70-specific CAR-T cells using a construct containing a humanized 41D12-based scFv and a 41BB-CD3ζ intracellular signaling domain. Cytotoxicity, cytokine release, and proliferation in antigen stimulation, CD107a assay, and CFSE assays were used to demonstrate the potent anti-leukemia activity in vitro. A Molm-13 xenograft mouse model was established to evaluate the anti-leukemic activity of CD70 CAR-T in vivo. CFU assay was explored to assess the safety of CD70 CAR-T on HSC.
CD70 heterogeneously expressed on AML primary cells, including leukemia blasts, leukemic progenitor, and stem cells, but not expressed on normal HSCs and majority of blood cells. Anti-CD70 CAR-T cells exhibited potent cytotoxicity, cytokines production, and proliferation when incubated with CD70+ AML cell lines. It also displayed robust anti-leukemia activity and prolonged survival in Molm-13 xenograft mouse model. However, such CAR-T cell therapy did not completely eliminate leukemia in vivo.
Our study reveals that anti-CD70 CAR-T cells are a new potential treatment for AML. However, such CAR-T cell therapy did not completely eliminate leukemia in vivo, suggesting that future studies aiming to generate innovative combinatorial CAR constructs or to increase CD70 expression density on leukemia cell surface to prolong the life-span of CAR-T cells in the circulation will be needed in order to optimize CAR-T cell responses for AML.