i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen 208, Porto, Portugal; INEB - Instituto Nacional de Engenharia Biomédica, Universidade do Porto, Rua Alfredo Allen 208, Porto 4200-180, Portugal; Drug Delivery and Targeting Group, Molecular Biology and Biochemistry Research Centre for Nanomedicine (CIBBIM-Nanomedicine), Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain.
Drug Delivery and Targeting Group, Molecular Biology and Biochemistry Research Centre for Nanomedicine (CIBBIM-Nanomedicine), Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Networking Research Centre for Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), Instituto de Salud Carlos III, Zaragoza, Spain.
J Control Release. 2021 Mar 10;331:198-212. doi: 10.1016/j.jconrel.2021.01.022. Epub 2021 Jan 20.
Colorectal cancer (CRC) is a highly prevalent disease worldwide. Patient survival is hampered by tumor relapse and the appearance of drug-resistant metastases, which are sustained by the presence of cancer stem cells (CSC). Specific delivery of anti-CSC chemotherapeutic drugs to tumors by using targeted drug delivery systems that can also target CSC sub-population might substantially improve current clinical outcomes. CD44v6 is a robust biomarker for advanced CRC and CSC, due to its functional role in tumorigenesis and cancer initiation process. Here, we show that CD44v6-targeted polymeric micelles (PM) loaded with niclosamide (NCS), a drug against CSC, is a good therapeutic strategy against colorectal CSC and circulating tumor cells (CTC) in vivo. HCT116 cells were sorted according to their CD44v6 receptor expression into CD44v6+ (high) and CDv44v6- (low) subpopulations. Accordingly, CD44v6+ cells presented stemness properties, such as overexpression of defined stemness markers (ALDH1A1, CD44v3 and CXCR4) and high capacity to form colonspheres in low attachment conditions. NCS-loaded PM functionalized with an antibody fragment against CD44v6 (Fab-CD44v6) presented adequate size, charge, and encapsulation efficiency. In addition, Fab-CD44v6 significantly increased PM internalization in CD44v6+ cells. Further, encapsulation of NCS improved its effectiveness in vitro, particularly against colonspheres, and allowed to increase its intravenous dosage in vivo by increasing the amount of NCS able to be administered without causing toxicity. Remarkably, functionalized PM accumulate in tumors and significantly reduce CTC in vivo. In conclusion, CD44v6 targeted PM meet the essential conditions to become an efficient anti-CSC therapy.
结直肠癌（CRC）是一种在全球范围内普遍存在的疾病。肿瘤复发和耐药性转移的出现阻碍了患者的生存，而这些转移是由癌症干细胞（CSC）的存在所维持的。通过使用能够靶向 CSC 亚群的靶向药物递送系统将抗 CSC 化疗药物特异性递送到肿瘤中，可能会大大改善当前的临床结果。CD44v6 是晚期 CRC 和 CSC 的强有力的生物标志物，因为它在肿瘤发生和癌症起始过程中发挥功能作用。在这里，我们表明，载有尼氯硝唑（NCS）的靶向 CD44v6 的聚合物胶束（PM）是一种针对结直肠 CSC 和循环肿瘤细胞（CTC）的体内治疗策略。根据其 CD44v6 受体表达，HCT116 细胞被分选成 CD44v6+（高）和 CD44v6-（低）亚群。相应地，CD44v6+细胞表现出干性特征，例如定义性干性标志物（ALDH1A1、CD44v3 和 CXCR4）的过度表达以及在低附着条件下形成结肠球体的高能力。用针对 CD44v6 的抗体片段（Fab-CD44v6）功能化的载有 NCS 的 PM 具有合适的大小、电荷和包封效率。此外，Fab-CD44v6 显著增加了 PM 在 CD44v6+细胞中的内化。此外，NCS 的包封提高了其在体外的有效性，特别是针对结肠球体，并且能够通过增加能够给予而不会引起毒性的 NCS 的量来增加其静脉内剂量。值得注意的是，功能化的 PM 在肿瘤中积累，并显著减少了体内的 CTC。总之，靶向 CD44v6 的 PM 满足成为有效的抗 CSC 治疗的基本条件。
