Department of Biomedical Engineering, Faculty of Medicine & Dentistry, University of Alberta, AB, Canada.
Department of Chemical & Materials Engineering, Faculty of Engineering, University of Alberta, AB, Canada.
J Control Release. 2019 Sep 28;310:141-154. doi: 10.1016/j.jconrel.2019.08.018. Epub 2019 Aug 17.
Despite development of effective tyrosine kinase inhibitors for treatment of chronic myeloid leukemia (CML), some patients do not effectively respond to the therapy and can display resistance in response to the drug therapy. To develop an alternative approach to CML therapy, we are exploring siRNA mediated silencing of the primary CML oncogene, BCR-ABL, by using non-viral (polymeric) delivery systems. In this study, a group of lipopolymers derived from low molecular PEIs substituted with linoleic acid (LA), α-linolenic acid (αLA) and cholesterol (Chol) was investigated for the first time for siRNA delivery to CML primary samples. The delivery efficiency in primary cells was equivalent to CML K562 cell line, and the lipopolymers gave effective internalization of siRNA depending on the nature of lipid substituent. The PEI-αLA (2.5 αLA/PEI), PEI-Chol (2.2 Chol/PEI), and PEI-LA (2.6 LA/PEI) lipopolymers used as BCR-ABL siRNA carriers (at 60 nM siRNA) reduced the BCR-ABL mRNA expression by 17% to 45%, and inhibited the formation of colonies by 24% to 41% in comparison with control siRNA in mononuclear cells. BCR-ABL siRNA treatment reduced the BCR-ABL mRNA expression by 50% in one of two CD34+ samples tested, and combination of BCR-ABL siRNA with imatinib (IM) treatment decreased the colony formation by 65% in one of two samples evaluated. The fact that no single polymer was universally effective in all patient samples may suggest patient-to-patient variability in terms of therapeutic responses to siRNA therapy. These results showed that a low dose of BCR-ABL siRNA could be used with lipopolymers to reduce BCR-ABL mRNA expression, CML cell survival and colony formation. This proof of principle study in CML primary cells can be applied to silencing of other therapeutic targets besides BCR-ABL and a study with larger patient samples is warranted for better identification of effective siRNA carriers.
尽管已经开发出有效的酪氨酸激酶抑制剂来治疗慢性髓性白血病（CML），但有些患者对治疗反应不佳，并且可能对药物治疗产生耐药性。为了开发治疗 CML 的替代方法，我们正在探索通过非病毒（聚合体）传递系统对主要 CML 致癌基因 BCR-ABL 进行 siRNA 介导的沉默。在这项研究中，首次研究了一组由低分子量 PEI 衍生的脂质体，这些脂质体用亚油酸（LA）、α-亚麻酸（αLA）和胆固醇（Chol）取代，用于向 CML 原代样本中递送 siRNA。在原代细胞中的递送效率与 CML K562 细胞系相当，并且脂质体根据脂质取代基的性质有效地进行了 siRNA 的内化。PEI-αLA（2.5αLA/PEI）、PEI-Chol（2.2Chol/PEI）和 PEI-LA（2.6LA/PEI）脂质体用作 BCR-ABL siRNA 载体（在 60 nM siRNA 时），使单核细胞中的 BCR-ABL mRNA 表达降低了 17%至 45%，与对照 siRNA 相比，集落形成减少了 24%至 41%。BCR-ABL siRNA 处理使在两个测试的 CD34+样本之一中 BCR-ABL mRNA 表达降低了 50%，并且 BCR-ABL siRNA 与伊马替尼（IM）联合治疗使在两个评估样本之一中的集落形成降低了 65%。没有一种聚合物在所有患者样本中普遍有效的事实可能表明，在对 siRNA 治疗的治疗反应方面，患者之间存在可变性。这些结果表明，低剂量的 BCR-ABL siRNA 可与脂质体一起使用，以降低 BCR-ABL mRNA 表达、CML 细胞存活和集落形成。在 CML 原代细胞中的这一原理验证研究可应用于除 BCR-ABL 之外的其他治疗靶点的沉默，并且需要更大的患者样本研究以更好地鉴定有效的 siRNA 载体。
