A Practical Approach to Tumor-Specific Aptamers for B-Cell Hematologic Malignancies

个性化医疗将大大提高癌症治疗的有效性；然而，制定切实可行的针对患者的策略仍然具有挑战性。一个独特的机会存在于B细胞源性恶性肿瘤中，它们通常在其B细胞受体（bcr）内表达具有可变区域（独特型，id）的表面免疫球蛋白（sIgs）。由于恶性细胞起源于单个克隆，这种sIg-Id分子对肿瘤是特异性的，对每个患者都是独一无二的。因此，针对sig - id可以实现个性化的疾病识别和治疗策略。使用患者特异性抗sig - id抗体的早期研究取得了有希望的结果，但被认为是不可持续的。在基于sig - id的诊断和治疗中，以高效、经济的方式生成个性化配体的技术仍然是一个未满足的需求。

Personalized medicine will greatly improve the effectiveness of cancer care; however, the development of practically attainable patient-specific strategies has remained challenging. One unique opportunity exists with B cell-derived malignancies, which often express surface immunoglobulins (sIgs) with variable regions (idiotypes, Ids) within their B-cell receptors (BCRs). As malignant cells originate from a single clone, such sIg-Id molecules are specific to the tumor and unique to each patient. Targeting sIg-Ids can hence enable personalized disease identification and treatment strategies. Early studies using patient-specific anti-sIg-Id antibodies yielded promising results but were deemed unsustainable. A technology to generate personalized ligands in a time-efficient and cost-effective manner remains an unmet need in sIg-Id-based diagnostics and therapeutics. Aptamers, i.e., single-stranded oligonucleotides that specifically bind to biological targets, offer an attractive solution to this unmet need. Aptamers are isolated from a randomized oligonucleotide library via an in vitro process known as SELEX, which is traditionally labor-intensive, time-consuming (up to a month), and impractical for personalized aptamer generation. In contrast, we have developed a microfluidic platform, called microSELEX (μSELEX), which has been used to isolate aptamers for protein biomarkers, including Id regions of monoclonal antibodies from patients with multiple myeloma and COVID-19. Given a monoclonal protein from a patient sample, the platform is capable of rapidly isolating personalized anti-Id aptamers within ~10 hours. We propose to explore time-efficient and cost-effective μSELEX isolation of patient-specific DNA aptamers targeting sIg-Ids of tumor B cells for B-cell hematologic malignancies. We will first establish an optimal μSELEX protocol using B cell-derived cell lines, then isolate anti-sIg aptamers against tumor B cells obtained from peripheral blood samples of B cell lymphoma patients, and finally demonstrate noninvasive peripheral blood-based monitoring of minimal residual disease by using the aptamers to detect circulating tumor B cells. In addition to enabling timely identification of minimal residual disease for more precise clinical decision making, anti-sIg-Id aptamers can also be used as therapeutic ligands to enable personalized and precisely targeted therapy for more effective disease treatment. Such personalized aptamers can hence potentially lead to transformative changes in the care of patients with B-cell hematologic malignancies.