Targeting microRNAs in the tumor microenvironment with pHLIP conjugated next generation chemically modified PNAs

弥漫性大B细胞淋巴瘤（DLBCL）是美国常见的癌症，导致数万人死亡 发病率呈上升趋势。microRNA（miRNAs）是一种小的非编码RNA，通常被错误编码。 在淋巴瘤和白血病中受到调节。特别是，miR-155在多发性淋巴瘤/白血病亚组中上调， 类型（特别是DLBCL）。此外，有直接证据表明，其过度表达导致人类DLBCL。 DLBCL异种移植物和转基因小鼠模型。有趣的是，通过过度表达miR-16诱导的肿瘤， 155依赖于miRNA的持续表达来生存，因为如果miRNA被撤回， 通过细胞凋亡迅速消退。这种“癌基因成瘾”的特性使这类miRNAs成为理想的靶点 用于未来的抗癌治疗，并促进了临床试验的启动，以通过肿瘤内给药抑制oncomiR-155 在皮肤T细胞淋巴瘤（CTCL）和DLBCL中递送Cobomarsen。虽然取得了显著进展， 在过去的几年里，FDA批准了反义和RNAi药物，治疗性miRNA靶向， 目前仍然落后，主要是由于与选择性输送和毒性有关的问题。 在这里，我们建议利用致癌基因成瘾的惊人性质，开发定制的潜在治疗方法 以安全有效的方式对抗这种关键的肿瘤抑制剂。我们之前发布了一种方法， 使用pHLIP（pH低）将抗miR-155肽核酸（PNA）靶向酸性肿瘤微环境 插入肽），在淋巴瘤小鼠模型中具有显著效果。pHLIP是36个氨基酸的肽， 在低pH值（< pH 6.5）下采用α-螺旋构象变化，有利于其C-末端插入 酸性肿瘤微环境中的脂质双层。在这里，我们提出了一个多学科的项目，重点是 翻译下一代PNA和pHLIP技术，以实现高度特异性靶向和提高疗效 靶向miR-155成瘾性癌症中酸性组织中的致癌miR-155，具有有利的治疗窗口。 与大多数核酸不同，PNA是一种合成的DNA模拟物，其中磷酸二酯骨架是 被中性N-（2-氨基乙基）甘氨酸骨架取代。PNA可以以高亲和力结合单链靶标。 PNA具有特异性和亲和力，对蛋白酶或核酸酶不敏感，使其成为用于治疗癌症的理想分子。 靶向miRNA。为了进一步提高antimiR PNA的有效性，我们将开发一类新的PNA， 类似物，称为γ PNA（gPNA），其是构象上预组织的，因此具有有利的 结合以及溶解度特性，这将增加它们作为antimiR试剂的有效性。就证明了 我们的下一代稳定的pHLIP缀合的化学修饰的γ PNA（gPNA）作为癌症的原理 治疗学方面，我们建议在该项目中测试淋巴瘤癌症模型中的递送和功效（细胞系， 异种移植物、PDX和GEMM），最终目标是制备适合于临床试验的药物。调查 这些利用针对酸性微环境的新型寡聚体的miRNA成瘾的方法将 为淋巴瘤/白血病和其他肿瘤的分子靶向癌症治疗的发展提供信息。

Diffuse large B-cell lymphoma (DLBCL) is a common cancer in the US, causing tens of thousands of deaths each year and its incidence is on the rise. MicroRNAs (miRNAs) are small non-coding RNAs that are often mis- regulated in lymphoma and leukemia. In particular, miR-155 is up-regulated in multiple lymphoma/leukemia sub- types (notably DLBCL). Plus, direct evidence exists to show that its over-expression causes DLBCL in human DLBCL xenografts and transgenic mouse models. Interestingly, the tumors induced by over-expression of miR- 155 depend on the continued expression of the miRNA for survival, since if the miRNA is withdrawn, the tumors rapidly regress via apoptosis. This property of “oncogene addiction” makes this class of miRNAs ideal targets for future anti-cancer therapy and promoted the initiation of a clinical trial to inhibit oncomiR-155 via intratumoral delivery of Cobomarsen in Cutaneous T-cell Lymphoma (CTCL) and DLBCL. While remarkable progress has been made in the past few years with FDA approvals of antisense and RNAi drugs, therapeutic miRNA targeting still lags behind, largely due to issues related to selective delivery and toxicity. Here we propose to exploit the striking nature of oncogene addiction to develop potential therapeutics tailored to antagonize this crucial oncomiR in a safe and effective manner. We previously published an approach to target anti-miR-155 peptide nucleic acids (PNAs) to the acidic tumor microenvironment using pHLIP (pH Low Insertion Peptide), with significant effects in a mouse model of lymphoma. pHLIP is a 36-amino acid peptide that adopts an α-helical conformational change at low pH (< pH 6.5) that facilitates insertion of its C-terminus across lipid bilayers in the acidic tumor microenvironment. Here we propose a multi-disciplinary project focused on translating next-generation PNA and pHLIP technology to allow highly-specific targeting and improved efficacy targeting oncogenic miR-155 in acidic tissues in miR-155-addicted cancers, with a favorable therapeutic window. Unlike most nucleic acids, PNAs are a synthetic DNA mimics in which the phosphodiester backbone is substituted with a neutral N-(2-aminoethyl) glycine backbone. PNAs can bind single-strand targets with high specificity and affinity and are not susceptible to proteases or nucleases, making PNAs ideal molecules for targeting miRNAs. To further improve the effectiveness of antimiR PNAs, we will exploit a new class of PNA analogs, designated gamma PNAs (gPNAs) that are conformationally pre-organized and so have advantageous binding as well as solubility properties that should increase their effectiveness as antimiR agents. As proof of principle for our stable next generation pHLIP-conjugated, chemically modified gamma PNAs (gPNAs) as cancer therapeutics, we propose to test delivery and efficacy in lymphoma cancer models in this project (cell lines, xenografts, PDX and GEMMs), with the ultimate goal of preparing a drug suitable for clinical trials. Investigation of these methods to exploit miRNA addiction with novel oligomers targeted to the acidic microenvironment will inform the development of molecularly targeted cancer therapeutics for lymphoma/leukemia and other tumors.