Hydrophobic interactions between polymeric carrier and palmitic acid-conjugated siRNA improve PEGylated polyplex stability and enhance in vivo pharmacokinetics and tumor gene silencing.
Hydrophobic interactions between polymeric carrier and palmitic acid-conjugated siRNA improve PEGylated polyplex stability and enhance in vivo pharmacokinetics and tumor gene silencing.
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DOI：
10.1016/j.biomaterials.2016.04.017
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发表时间：
2016-08
期刊：
影响因子：
14
通讯作者：
Duvall CL
中科院分区：
文献类型：
--
作者：
Sarett SM;Werfel TA;Chandra I;Jackson MA;Kavanaugh TE;Hattaway ME;Giorgio TD;Duvall CL
形成稳定的、长循环的siRNA多聚体是静脉给药、聚合RNAi癌症治疗方法翻译中的一个重大挑战。在这里，我们报告了通过连接到棕榈酸(SIPA)的siRNA疏水改善了聚乙二醇化纳米多聚体(SIPA-NPs)的稳定性、体内药代动力学和肿瘤基因沉默，核心具有平衡的阳离子和疏水含量(相对于由未经修饰的siRNA形成的类似多聚体，si-NPs)。与未修饰的siRNA相比，疏水的siPA以较低的电荷比(N+：P−)负载到NPs中，并且与竞争的多阴离子肝素和血清接触时，SIPA-NPs具有更好的抗siRNA货物拆解的能力。在体外，SipA-NPs增加了MDA-MB-231乳腺癌细胞的摄取(100%阳性细胞对60%阳性细胞)，但与si-NPs相比，模型基因荧光素酶表现出同等的沉默。在小鼠体内模型中，静脉注射SipA-NPs的循环半衰期是si-NPs的两倍，导致原位MDA-MB-231乳腺肿瘤的siRNA生物分布增加了2倍。SIPA-NPs循环半衰期的增加取决于siRNA和NP核心成分的疏水相互作用，而不仅仅是siRNA的疏水作用，因为SIPA在使用具有完全阳离子核心的聚合物时，与未经修饰的siRNA相比，并不有助于改善循环时间。静脉注射SipA-NPs对模型基因荧光素酶也有显著的体内沉默作用(一次治疗后24小时~40%，两次治疗后48小时~60%)，而Si-NPs仅在两次治疗后才产生显著的沉默作用。这些数据表明，与仅包含静电作用的传统制剂相比，通过siRNA载体和聚合物载体之间的疏水和静电相互作用来稳定聚乙二醇化的siRNA多聚体可以改善体内的药代动力学和肿瘤基因沉默。
Formation of stable, long-circulating siRNA polyplexes is a significant challenge in translation of intravenously-delivered, polymeric RNAi cancer therapies. Here, we report that siRNA hydrophobization through conjugation to palmitic acid (siPA) improves stability, in vivo pharmacokinetics, and tumor gene silencing of PEGylated nanopolyplexes (siPA-NPs) with balanced cationic and hydrophobic content in the core (relative to the analogous polyplexes formed with unmodified siRNA, si-NPs). Hydrophobized siPA loaded into the NPs at a lower charge ratio (N+:P−) relative to unmodified siRNA, and the siPA-NPs had superior resistance to siRNA cargo unpackaging in comparison to si-NPs upon exposure to the competing polyanion heparin and serum. In vitro, siPA-NPs increased uptake in MDA-MB-231 breast cancer cells (100% positive cells vs. 60% positive cells) but exhibited equivalent silencing of the model gene luciferase relative to si-NPs. In vivo in a murine model, the circulation half-life of intravenously-injected siPA-NPs was double that of si-NPs, resulting in a >2-fold increase in siRNA biodistribution to orthotopic MDA-MB-231 mammary tumors. The increased circulation half-life of siPA-NPs was dependent upon the hydrophobic interactions of the siRNA and the NP core component and not just siRNA hydrophobization, as siPA did not contribute to improved circulation time relative to unmodified siRNA when delivered using polyplexes with a fully cationic core. Intravenous delivery of siPA-NPs also achieved significant silencing of the model gene luciferase in vivo (~40% at 24 hours after one treatment and ~60% at 48 hours after two treatments) in the murine MDA-MB-231 tumor model, while si-NPs only produced a significant silencing effect after two treatments. These data suggest that stabilization of PEGylated siRNA polyplexes through a combination of hydrophobic and electrostatic interactions between siRNA cargo and the polymeric carrier improves in vivo pharmacokinetics and tumor gene silencing relative to conventional formulations comprising only electrostatic interactions.