CAS Key Laboratory of Brain Function and Disease, and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China.
J Control Release. 2012 Aug 10;161(3):875-83. doi: 10.1016/j.jconrel.2012.05.015. Epub 2012 May 14.
The targeted delivery of small interfering RNA (siRNA) to specific tumor tissues and tumor cells remains as one of the key challenges in the development of RNA interference as a therapeutic application. To target breast cancer, we developed a therapeutic delivery system using a fusion protein of an anti-Her2 single-chain antibody fragment with a positively charged protamine, namely F5-P, as the carrier to specifically deliver siRNA-targeting DNA methyltransferases 1 and/or 3b genes (siDNMTs) into Her2-expressing breast tumor cells. The carrier F5-P, expressed by the Escherichia coli system, was able to bind siRNA molecules and specifically deliver the siRNA to Her2-expressing BT474 breast cancer cells but not Her2-nonexpressing MDA-MB-231 breast cancer cells, while delivery of siDNMTs to BT474 cells successfully silenced the expression of targeted DNA methyltransferases (DNMTs) and facilitated the de-methylation of the RASSF1A tumor suppressor gene promoter, leading to the suppression of tumor cell proliferation. Moreover, as demonstrated in the BT474 xenograft murine model, F5-P successfully delivered siRNA into a Her2-expressing breast tumor, and tumor growth inhibition was mediated by an intravenous injection of F5-P/siDNMTs complex by down-regulating the expression of DNMTs and restoring tumor suppressor gene expression. These data suggest that the delivery of siDNMTs by F5-P could be used to treat Her2-expressing breast cancer.
靶向递送小干扰 RNA（siRNA）至特定肿瘤组织和肿瘤细胞仍然是 RNA 干扰作为治疗应用发展的关键挑战之一。为了靶向乳腺癌，我们开发了一种治疗性递送系统，该系统使用抗 Her2 单链抗体片段与带正电荷鱼精蛋白的融合蛋白（即 F5-P）作为载体，将靶向 DNA 甲基转移酶 1 和/或 3b 基因（siDNMTs）的 siRNA 特异性递送至 Her2 表达的乳腺癌肿瘤细胞。载体 F5-P 通过大肠杆菌系统表达，能够结合 siRNA 分子并将 siRNA 特异性递送至 Her2 表达的 BT474 乳腺癌细胞，但不能递送至 Her2 不表达的 MDA-MB-231 乳腺癌细胞，而将 siDNMTs 递送至 BT474 细胞成功沉默了靶向 DNA 甲基转移酶（DNMTs）的表达，并促进了 RASSF1A 肿瘤抑制基因启动子的去甲基化，从而抑制了肿瘤细胞的增殖。此外，正如在 BT474 异种移植鼠模型中所证明的那样，F5-P 成功地将 siRNA 递送至 Her2 表达的乳腺癌中，并且通过静脉注射 F5-P/siDNMTs 复合物下调 DNMTs 的表达并恢复肿瘤抑制基因表达来介导肿瘤生长抑制。这些数据表明，F5-P 递送 siDNMTs 可用于治疗 Her2 表达的乳腺癌。
