Therapeutic Efficacy of Bifunctional siRNA Combining TGF-β1 Silencing with RIG-I Activation in Pancreatic Cancer
Therapeutic Efficacy of Bifunctional siRNA Combining TGF-β1 Silencing with RIG-I Activation in Pancreatic Cancer
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DOI：
10.1158/0008-5472.can-11-3850
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发表时间：
2013-03-15
期刊：
影响因子：
11.2
通讯作者：
Schnurr, Max
中科院分区：
文献类型：
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作者：
Ellermeier, Jonathan;Wei, Jiwu;Schnurr, Max
胰腺癌中TGF-β信号失调促进肿瘤生长、侵袭、转移和有效的免疫抑制网络。破坏这种肿瘤促进途径的策略是通过siRNA沉默TGF-β。通过在siRNA（ppp-siRNA）的5'末端引入三磷酸基团，基因沉默可以通过胞质解旋酶视黄酸诱导基因I（RIG-I）（一种普遍表达的识别病毒RNA的受体）与免疫激活相结合。我们通过显示胰腺癌细胞中RIG-I的活化诱导IRF-3磷酸化、I型IFN、趋化因子CXCL 10的产生以及半胱天冬酶-9介导的肿瘤细胞凋亡来验证RIG-I作为治疗靶点。接下来，我们产生了一种结合RIG-I激活和TGF-β（1）基因沉默的双功能ppp-siRNA（ppp-TGF-β），并研究了其在胰腺癌原位Panc 02小鼠模型中的治疗效果。静脉注射ppp-TGF-β可降低全身和肿瘤相关TGF-β水平。此外，它诱导高水平的I型IFN和CXCL 10在血清和肿瘤组织中，全身免疫细胞激活，并在体内的深刻的肿瘤细胞凋亡。与单独的ppp-RNA或TGF-β siRNA相比，用ppp-TGF-β治疗已建立肿瘤的小鼠显著延长了存活期。此外，我们观察到活化的CD 8（+）T细胞向肿瘤的募集和CD 11b（+）Gr-1（+）骨髓细胞的频率降低。治疗效果依赖于CD 8（+）T细胞，而自然杀伤细胞是不稳定的。总之，结合TGF-β基因沉默和RIG-I信号传导，通过打破肿瘤诱导的CD 8（+）T细胞抑制，对胰腺癌具有有效的抗肿瘤疗效。Cancer Res; 73（6）; 1709-20. (c)2013年AACR。
Deregulated TGF-beta signaling in pancreatic cancer promotes tumor growth, invasion, metastasis, and a potent immunosuppressive network. A strategy for disrupting this tumor-promoting pathway is silencing TGF-beta by siRNA. By introducing a triphosphate group at the 5' end of siRNA (ppp-siRNA), gene silencing can be combined with immune activation via the cytosolic helicase retinoic acid-inducible gene I (RIG-I), a ubiquitously expressed receptor recognizing viral RNA. We validated RIG-I as a therapeutic target by showing that activation of RIG-I in pancreatic carcinoma cells induced IRF-3 phosphorylation, production of type I IFN, the chemokine CXCL10, as well as caspase-9-mediated tumor cell apoptosis. Next, we generated a bifunctional ppp-siRNA that combines RIG-I activation with gene silencing of TGF-beta(1) (ppp-TGF-beta) and studied its therapeutic efficacy in the orthotopic Panc02 mouse model of pancreatic cancer. Intravenous injection of ppp-TGF-beta reduced systemic and tumor-associated TGF-beta levels. In addition, it induced high levels of type I IFN and CXCL10 in serum and tumor tissue, systemic immune cell activation, and profound tumor cell apoptosis in vivo. Treatment of mice with established tumors with ppp-TGF-beta significantly prolonged survival as compared with ppp-RNA or TGF-beta siRNA alone. Furthermore, we observed the recruitment of activated CD8(+) T cells to the tumor and a reduced frequency of CD11b(+) Gr-1(+) myeloid cells. Therapeutic efficacy was dependent on CD8(+) T cells, whereas natural killer cells were dispensable. In conclusion, combing TGF-beta gene silencing with RIG-I signaling confers potent antitumor efficacy against pancreatic cancer by breaking tumor-induced CD8(+) T cell suppression. Cancer Res; 73(6); 1709-20. (c) 2013 AACR.