Intravenous siRNA Silencing of Survivin Enhances Activity of Mitomycin C in Human Bladder RT4 Xenografts.
Intravenous siRNA Silencing of Survivin Enhances Activity of Mitomycin C in Human Bladder RT4 Xenografts.
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DOI：
10.1016/j.juro.2015.02.036
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发表时间：
2015-07
期刊：
影响因子：
--
通讯作者：
Lu Z
中科院分区：
文献类型：
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作者：
Cui M;Au JL;Wientjes MG;O'Donnell MA;Loughlin KR;Lu Z
Survivin抑制细胞凋亡，使肿瘤细胞摆脱治疗诱导的衰老。survivin的高表达与膀胱癌的侵袭性和复发有关。本研究在体外和体内研究了在人RT4膀胱移行细胞肿瘤中，siRNA是否降低了survivin的表达，survivin沉默是否增强了丝裂霉素C （MMC）的活性。使用两种新开发的聚乙二醇化阳离子脂质体载体（PCat, PPCat）评估siRNA治疗的有效性。两个携带体都使用一种促聚变脂质来破坏内体膜的稳定。一个载体（PPCat）进一步含有紫杉醇，以增强生存素siRNA （siSurvivin）的体内传递和转染。通过短期和长期细胞毒性试验（微四氮唑和克隆原性）评估体外抗肿瘤活性。对小鼠皮下肿瘤进行体内静脉注射治疗。非靶标sirna在体内和体外均无抗肿瘤活性。50%细胞毒浓度的MMC处理培养细胞可提高survivin mRNA和蛋白水平；添加PPCat或含有siSurvivin的PCat逆转了survivin诱导，增强了MMC活性（p<0.05）。在荷瘤小鼠中，单剂MMC延迟肿瘤生长，残余肿瘤中survivin蛋白水平几乎增加了两倍，而添加PPCat-siSurvivin完全逆转了MMC诱导的survivin，增强了MMC活性（p<0.05），而PPCat-siSurvivin本身只产生少量的survivin降低（<10%）。结果表明，MMC和PPCat-siSurvivin在体内具有有效的沉默作用和协同作用。这种组合代表了一种潜在的有用的化学基因治疗膀胱癌。
Survivin inhibits apoptosis and enables tumor cells to escape from therapy-induced senescence. High expression of survivin is associated with bladder cancer aggressiveness and recurrence. The present study evaluated if survivin expression is reduced by siRNA and if survivin silencing enhances the activity of mitomycin C (MMC), in human RT4 bladder transitional cell tumors in vitro and in vivo. The effectiveness of siRNA therapy was evaluated using two newly developed pegylated cationic liposome carriers (PCat, PPCat). Both carries used a fusogenic lipid to destabilize the endosomal membrane. One carrier (PPCat) further contained paclitaxel to enhance the in vivo delivery and transfection of survivin siRNA (siSurvivin). In vitro antitumor activity was evaluated using short and long term cytotoxicity assays (microtetrazolium and clonogenicity). In vivo intravenous therapy was evaluated in mice bearing subcutaneous tumors. The nontarget-siRNA had no antitumor activity in vitro or in vivo. Treatment of cultured cells with MMC at 50% cytotoxic concentration enhanced survivin mRNA and protein levels; addition of PPCat or PCat containing siSurvivin reversed the survivin induction and enhanced the MMC activity (p<0.05). In tumor-bearing mice, single agent MMC delayed tumor growth and nearly tripled the survivin protein level in residual tumors, whereas addition of PPCat-siSurvivin, which by itself yielded a minor survivin reduction (<10%), completely reversed the MMC-induced survivin and enhanced the MMC activity (p<0.05). The results indicate effective in vivo survivin silencing and synergism between MMC and PPCat-siSurvivin. This combination represents a potentially useful chemo-gene therapy for bladder cancer.