Department of Chemical and Materials Engineering , University of Alberta , Edmonton T6G 1H9 , Alberta , Canada.
Department of Oncology , University of Alberta, Cross Cancer Institute , Edmonton T6G 1Z2 , Alberta , Canada.
Biomacromolecules. 2018 Oct 8;19(10):4052-4058. doi: 10.1021/acs.biomac.8b01066. Epub 2018 Sep 6.
Strong signaling cascades derived from upregulation and overexpression of growth factors such as the EGF-family (epidermal growth factors) have been crucially related to cancer pathogenesis. Gene silencing techniques to modulate the expression of oncogenes and tumor suppresor genes are a strategy that shows great promise for cancer management but still faces some limitations in the design of biocompatible and effective vectors. In this study, we synthesized, by reversible addition-fragmentation chain transfer (RAFT) polymerization, several acid degradable galactose-based hyperbranched cationic polymers with varying molecular weights (10 to 20 kDa) and compositions with 2-lactobioamidoethyl methacrylamide [LAEMA] and 2-aminoethyl methacrylamide hydrochloride [AEMA] at different ratios (2.0, 1.0, and 0.5). These polymers were then evaluated for their ability to enhance Epidermal Growth Factor Receptor (EGFR) knockdown in cervical carcinoma. All the polymer constructs have enhanced capabilities to condensate siRNA (small interfering RNA), showing low toxicity at higher LAEMA:AEMA ratios (1.0 and 2.0). Western blot assays were conducted to quantify the EGFR expression of each treatment group demonstrating superior gene knockdown efficiency for the polymers having a LAEMA:AEMA ratio of 2.0 than the lower ratio counterparts; while maintaining low toxicity levels. Gene silencing of EGFR of up to 60% was achieved with acid degradable polymers having 10 kDa molecular weight and a LAEMA:AEMA ratio of 2.0. The superior stability of the polyplexes under physiological conditions and the low cytotoxicity observed in the 48 h post-transfection demonstrated the high potential of these acid degradable galactose-based hyperbranched cationic polymers for EGFR silencing treatment applications at the clinical level.
强烈的信号级联反应源自生长因子（如表皮生长因子家族）的上调和过表达，与癌症发病机制密切相关。基因沉默技术可调节癌基因和肿瘤抑制基因的表达，是一种具有广阔前景的癌症治疗策略，但在生物相容性和有效载体的设计方面仍面临一些限制。在这项研究中，我们通过可逆加成-断裂链转移（RAFT）聚合合成了几种酸可降解的基于半乳糖的超支化阳离子聚合物，其分子量（10 至 20 kDa）和组成有所不同，其中含有 2-乳酰氨乙基甲基丙烯酰胺[LAEMA]和 2-氨基乙基甲基丙烯酰胺盐酸盐[AEMA]，比例分别为 2.0、1.0 和 0.5。然后评估了这些聚合物增强表皮生长因子受体（EGFR）在宫颈癌中敲低的能力。所有聚合物结构都增强了小干扰 RNA（siRNA）的凝聚能力，在更高的 LAEMA:AEMA 比例（1.0 和 2.0）下显示出较低的毒性。进行了 Western blot 分析以量化每个治疗组的 EGFR 表达，结果表明 LAEMA:AEMA 比例为 2.0 的聚合物具有更高的基因敲低效率，优于比例较低的对应物；同时保持低毒性水平。具有 10 kDa 分子量和 LAEMA:AEMA 比例为 2.0 的酸可降解聚合物可使 EGFR 基因沉默高达 60%。在生理条件下，聚合物的稳定性更高，转染后 48 小时观察到的细胞毒性较低，这表明这些基于半乳糖的酸可降解超支化阳离子聚合物在临床水平上具有用于 EGFR 沉默治疗的巨大潜力。
