Although the CD20-targeted monoclonal antibody rituximab (RTX) has revolutionized the therapeutic landscape for B-cell malignancy, relapsed and refractory disease due to RTX resistance continue to constitute major challenges, illustrating the need for better therapies. Here, we apply drug-free macromolecular therapeutics (DFMT) that amplifies CD20 cross-linking to enhance apoptosis in RTX-resistant cells. Bispecific engager (anti-CD20 Fab′ conjugated with oligonucleotide1) pretargets CD20 and the deletion of Fc-region minimizes its premature endocytosis in resistant cells that rapidly internalize and consume CD20/RTX complexes. Second-step delivery of multivalent polymeric effector (linear copolymer conjugated with multiple copies of complementary oligonucleotide 2) simultaneously hybridizes multiple CD20-bound engagers and strengthens CD20 ligation. Moreover, the restoration of CD20 expression by the pretreatment of cells with a polymer-gemcitabine conjugate, a CD20 expression enhancer, unleashes the full potential of DFMT in the CD20-deficient resistant cells. Hence, amplification of CD20 cross-linking is achieved by (1) the enhancement of surface CD20 accessibility, (2) the increase in CD20 expression, and (3) multimeric CD20 binding, which ultimately translates into the amplified activation of a wide range of innate apoptotic responses. We demonstrated that the altered molecular signaling pathway that originally results in RTX resistance could be circumvented and compensated by other DFMT-augmented pathways. Of note, our preliminary data provide proof-of-concept that CD20 cross-linking amplification emerges as an important strategy for overcoming RTX resistance.

中文翻译：

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利妥昔单抗耐药 B 淋巴瘤细胞中 CD20 交联的扩增增强了无药大分子治疗的细胞凋亡诱导


尽管靶向 CD20 的单克隆抗体利妥昔单抗 (RTX) 彻底改变了 B 细胞恶性肿瘤的治疗格局，但由于 RTX 耐药而导致的复发和难治性疾病仍然构成重大挑战，这表明需要更好的治疗方法。在这里，我们应用无药大分子疗法 (DFMT) 放大 CD20 交联，以增强 RTX 耐药细胞的凋亡。双特异性接合剂（与寡核苷酸 1 缀合的抗 CD20 Fab'）预靶向 CD20，并且 Fc 区的删除可最大程度地减少其在快速内化并消耗 CD20/RTX 复合物的耐药细胞中的过早内吞作用。多价聚合效应物（与多个互补寡核苷酸 2 拷贝缀合的线性共聚物）的第二步递送同时杂交多个 CD20 结合接合体并加强 CD20 连接。此外，通过用聚合物-吉西他滨缀合物（CD20表达增强剂）预处理细胞来恢复CD20表达，在CD20缺陷的耐药细胞中释放DFMT的全部潜力。因此，CD20 交联的放大是通过以下方式实现的：(1) 表面 CD20 可及性的增强，(2) CD20 表达的增加，以及 (3) 多聚体 CD20 结合，最终转化为多种 CD20 的放大激活。先天性细胞凋亡反应。我们证明，最初导致 RTX 耐药的分子信号传导途径的改变可以通过其他 DFMT 增强途径来规避和补偿。值得注意的是，我们的初步数据提供了概念证明，即 CD20 交联扩增成为克服 RTX 耐药性的重要策略。