Aptamer mediated silencing of the spliceosome machinery to increase the immunogenicity of metastatic breast cancer

即使FDA批准Atezolizumab联合NAB-Paclitaxel治疗PDL1阳性三联症 阴性乳腺癌、转移性乳腺癌仍是一种致命疾病。检查站的适度影响 这种疾病的抑制剂治疗可以部分地解释为相对较低的肿瘤突变负担，较低的 转移性乳腺癌中新抗原的表达和免疫原性总体较低 检查点抑制药非常有效的恶性肿瘤。最新的RNA测序和MHC-肽组 对接受检查点抑制治疗的患者的肿瘤分析揭示了 新抗原库中的内含子衍生表位。在乳腺癌中，这些内含子衍生的新抗原效果很差。 表达是因为剪接体机械的结构性上调。 在这里，我们将测试适体介导的靶向沉默SnRPE的假设，SnRPE是 剪接体机制，可以提高乳腺癌的免疫原性，并与抗PD1在 根治转移性乳腺癌。对于这种靶向治疗，我们已经确定了两个RNA适配子 即可在体外和体内识别和识别小鼠和人类转移性乳腺癌细胞。RNA适配子是 由于其三维结构，小分子寡核苷酸能够以高亲和力识别其配体。适配子 通过化学合成具有核糖核酸酶抗性和缺乏免疫原性的骨架，并可以 进行改进，以改善药代动力学和治疗效果。我们已经将我们的适配子与 SiRNA对SnRPE的抑制作用，并显示了其体外效应。 在这项研究中，我们将使用两种侵袭性的小鼠乳腺癌模型：4T1和E0771。 两种不同的遗传背景。首先，我们将描述免疫系统在抗肿瘤中的作用 使用NSG和具有免疫能力的小鼠的反应，耗尽实验，并通过表征肿瘤 微环境与抗肿瘤免疫。然后，我们将检测适体嵌合体的治疗效果 作为单一疗法或与检查点抑制疗法和针对内含子衍生的疫苗一起接种 治疗转移性乳腺癌的新表位。 我们预计这种治疗将具有良好的耐受性，并将增加肿瘤的免疫原性和 检查点抑制疗法的疗效。由于我们的适配子识别老鼠和人类的转移瘤 对于癌症，临床上阳性发现的翻译可能应该得到便利，并且在未来可能会有 对转移性乳腺癌的重要影响，允许以最小的副作用根除和/或遏制其 效果。

Even with the FDA approval of Atezolizumab in combination with nab-Paclitaxel for PDL1 positive triple negative breast cancer, metastatic breast cancer is still a deadly disease. The modest impact of checkpoint inhibitor therapy in this disease can be partially explained by the relatively low tumor mutation burden, by the low expression of neoantigens and the overall low immunogenicity of metastatic breast cancer compare to other malignancies in which checkpoint inhibitors are highly effective. Recent RNA sequencing and MHC-peptidome analyses of tumors from patients undergoing checkpoint inhibition therapy revealed the important contribution of intron-derived epitopes in the neoantigen pools. In breast cancer these intron-derived neoantigens are poorly expressed because of the constitutive upregulation of the spliceosome machinery. Here we will test the hypothesis that aptamer mediated targeted silencing snRPE, a key component of the spliceosome machinery, can increase breast cancer immunogenicity and synergize with anti-PD1 in the eradication of metastatic breast cancer. Toward this targeted therapy, we have identified two RNA aptamers that can recognize and mouse and human metastatic breast cancer cells in vitro and in vivo. RNA aptamers are small oligonucleotides that because of their 3D structure can recognize their ligand with high affinity. Aptamers are chemically synthetized with a backbone that confer RNAse resistance and lack of immunogenicity and can be modified for improved pharmacokinetic and for therapeutic delivery. We have conjugated our aptamer with siRNA against snRPE and showed their in vitro efficacy. In this study, we will employ two aggressive model of mouse breast cancer: the 4T1 and the E0771 in two different genetic backgrounds. First, we will characterize the role of the immune system in the antitumor response using NSG and immune competent mice, depletion experiments, and by characterizing the tumor microenvironment and the anti-tumor immunity. Then, we will measure the therapeutic effect of aptamer chimera as monotherapy or in conjunction with checkpoint inhibition therapy and vaccination against intron derived neoepitopes for the treatment of metastatic breast cancer. We expect that this treatment will be well tolerated and will increase tumor immunogenicity and the efficacy of checkpoint inhibition therapy. Since our aptamers recognize both mouse and human metastatic cancers, the translation of positive finding in the clinic might should be facilitated and might have, in the future, an important impact on metastatic breast cancer allowing its eradication and/or containment with minimal side effect.