Therapeutic potential of antitumorigenic soluble MET variants induced by splicing interference

胃癌（GC）是世界范围内癌症相关死亡的第三大原因，中位总生存期 晚期疾病仅限1年。GC的一个重要部分是由于异常的HGF/MET轴信号传导，大多数 通常是由于MET受体基因扩增。然而，目前还没有有效的MET靶向疗法， 在最初的反应之后，耐药性经常迅速出现。发展新的、替代的 因此，有效抑制MET和其他RTK的方法对于找到治愈方法是必要的。 我们最近发现了一些新的可溶性诱饵RTKs异构体（sdRTKs），由替代方法产生， 剪接/内含子多聚腺苷酸化（IPA）机制，它可以作为RTK信号传导的有效天然抑制剂。我们 开发了一种基于反义的方法，以特异性和有效地诱导体外IPA使用和sdRTK表达， in vivo.这些化合物确定了一类新的药物，它们具有同时敲除 病理靶点，同时引入天然显性阴性同种型，从而大大提高其功效。 我们将应用这种基于反义的方法来促进IPA并刺激显性阴性的表达， 内源性可溶性诱饵MET抑制变体（sdMET），通常以低水平表达。sdMET对 细胞外配体结合和二聚化结构域，但缺乏跨膜和细胞内激酶结构域。 我们假设sdMET诱导化合物通过三重机制抑制HGF/MET信号传导： 直接去除全长MET受体mRNA，B）MET配体（HGF）的结合和螯合，和C）非- 与残余MET受体的产生性异源二聚化。我们进一步指出，由于所得产品 从靶细胞分泌，它们影响靶细胞和邻近细胞中的信号传导，并干扰 旁分泌和自分泌回路，从而产生放大效应。由于其作用机制不同于 目前的治疗，这种策略应该是有效的，在所有肿瘤依赖于HGF/MET信号，包括复发性 一个为此，我们将努力实现以下具体目标： 1)有效抑制性sdMET剪接变体的鉴定和表征。 2)胃癌细胞MET剪接/多聚腺苷酸化的反义重编程 诱导IPA的重定向化合物。 3)sdMET诱导的反义寡核苷酸在多发性胃癌中的治疗潜力的评估 癌症模型，在体外和体内。 这些结果将是重要的发展强大的新的调查工具和治疗方法， HGF/MET信号轴起决定性作用的任何癌症类型。这项研究的结果将是 在胃癌和其他肿瘤中，广泛地可转化为依赖于其他RTK和癌基因的疾病。类似 事实上，化合物可以类似地设计成直接靶向其他RTK或其他导致耐药性的靶点 和病理信号，或克服各种耐药机制。

Gastric cancer (GC) is the third leading cause of cancer-related death worldwide, with a median overall survival limited to 1 year for advanced disease. A significant fraction of GC is due to aberrant HGF/MET axis signaling, most commonly due to MET receptor gene amplification. However, no effective MET-targeted therapies are currently available, with resistance frequently emerging rapidly, following an initial response. The development of additional, alternative approaches to effectively inhibit MET and other RTKs is therefore a necessity for a cure to be found. We recently identified a number of novel soluble decoy RTKs isoforms (sdRTKs), generated by an alternative splicing/intronic polyadenylation (IPA) mechanism, which can act as potent natural inhibitors of RTK signaling. We developed an antisense-based method to specifically and effectively induce IPA usage and sdRTKs expression in vitro and in vivo. These compounds identify a new class of drugs that carry the advantage of simultaneously knocking down the pathological targets while introducing natural dominant-negative isoforms, thus greatly increasing their efficacy. We will apply this antisense-based approach to promote IPA and stimulate the expression of dominant-negative, endogenous soluble decoy MET inhibitory variants (sdMET), normally expressed at low levels. sdMETs encode the extracellular ligand-binding and dimerization domains, but lack the transmembrane and the intracellular kinase domains. We hypothesize that sdMET-inducing compounds suppress HGF/MET signaling by a three fold-mechanism: A) direct removal of full-length MET receptor mRNAs, B) binding and sequestration of MET ligand (HGF), and C) non- productive hetero-dimerization with residual MET receptors. We further posit that, as the resulting products are secreted from targeted cells, they affect signaling in both targeted and neighboring cells alike and interfere with paracrine and autocrine loops, thus wielding an amplified effect. Since the mechanism of action is different from that of current therapies, this strategy should be effective in all tumors that rely on HGF/MET signaling, including relapsing ones. To this end, we will pursue the following specific aims: 1) Identification and characterization of effective inhibitory sdMET splicing variants. 2) Reprogramming of MET splicing/polyadenylation in gastric cancer cells by antisense-based splicing redirection compounds that induce IPA. 3) Assessment of the therapeutic potential of sdMET-inducing antisense oligonucleotides in multiple gastric cancer models, in vitro and in vivo. These results will be important for the development of powerful novel investigative tools and therapeutic approaches in any cancer type where the HGF/MET signaling axis plays a determinant role. The findings emerging from this study will be broadly translatable to disease dependent on other RTKs and oncogenes, in gastric cancer and other tumors. Analogous compounds can in fact be similarly designed to directly target other RTKs or other targets responsible for drug-resistance and pathological signaling, or to overcome various mechanisms of resistance.