Non-cancer gene addition as anticancer strategy

描述（由申请人提供）：在过去十年中，癌症治疗发生了根本性的变化。基于驱动每个患者肿瘤发生的特定分子变化的新型疗法正在成为传统治疗的低毒性和更有效的替代品。因此，靶向生长因子受体EGFR-1和ErbB 2、雌激素核受体或BCR-ABL融合蛋白已经是完善的临床方案的一部分。然而，即使是这些理想的定制疗法也无法提供长期治愈，只能延缓疾病的进展。除了真正的癌症基因的改变之外，在肿瘤细胞中，多种正常的调节网络已经被重新排列以适应致瘤状态。由于这种差异，癌细胞的存活也取决于维持肿瘤稳态所必需的非癌基因。这种依赖性产生了肿瘤特异性的脆弱性，这些脆弱性在正常细胞中不存在，并且代表了治疗干预的机会。因此，我们假设干扰这些非癌症依赖性将导致系统故障，即肿瘤发生状态的停止。攻击非癌淋巴结的潜在治疗剂将具有大的治疗窗口，因为正常细胞中的靶标的非必需性质。此外，与针对癌症基因的疗法相反，为了逃避致死作用，肿瘤细胞可以去除/减弱致瘤性原发性病变（例如，肿瘤细胞可以去除/减弱致瘤性原发性病变）。致癌基因的激活），其本身将影响肿瘤适应性。 尽管肿瘤之间存在相对表面的相似性，但每个肿瘤中存在的特定改变极大地影响其内在特征。因此，每种癌症基因型将具有构成“遗传合成致死”（GSL）的一系列不同的非癌症依赖性。在本申请中，我们计划鉴定对维持携带特定癌症改变的肿瘤细胞的活力至关重要的非癌症基因，并探索它们作为定制疗法的肿瘤靶点的潜在用途。系统地消除基因组中的每个基因来寻找GSL代表了揭示肿瘤特异性弱点的有吸引力的方法。尽管这一过程已成功应用于酵母来剖析细胞途径，但其在哺乳动物中的应用非常有限，主要是因为缺乏适当的遗传工具。然而，最近RNA干扰（RNAi）技术已经消除了这一障碍。我们率先开发了基于RNAi的遗传工具，极大地促进了全基因组水平的功能丧失研究。因此，我们计划使用我们最先进的RNAi筛选技术作为干扰方法来寻找基因，这些基因在被阻断时，由于真正的癌症基因的存在而在乳腺癌细胞中产生GSL效应。在这里，我们建议使用“非癌附加物”的新概念来识别乳腺癌细胞的“阿喀琉斯之踵”。我们的工作假设完全颠覆了寻找治疗性癌症靶点的标准策略，该策略几乎完全集中在癌细胞中激活的通路的失活上。因此，我们相信，这项研究计划的成功完成将对下一代癌症治疗的设计产生重大影响。 公共卫生相关性：现代癌症治疗的主要挑战之一是消除肿瘤细胞而不影响正常细胞的能力。癌症治疗在过去十年中发生了根本性的变化。基于驱动每个患者肿瘤发生的特定分子变化的新型疗法正在成为经典治疗的低毒性和更有效的替代方案。然而，目前的定制疗法是次优的，尽管有一些例外，它们对癌症患者生存的影响仍然有限。在这里，我们建议通过逐个消除人类基因组中的每个基因来寻找基因，以确定乳腺癌的这种独特的“阿喀琉斯之踵”，这些基因在被阻断时只会降低肿瘤细胞的活力。这项研究计划的成功完成将为我们提供更有效、危害更小的乳腺癌治疗新靶点，并可能影响下一代癌症治疗方法的设计。

DESCRIPTION (provided by applicant): Cancer therapy has radically changed during the last decade. Novel therapies based on the specific molecular changes that drive tumorigenesis in every patient are emerging as low toxic and more efficient alternatives to classical treatments. Thus, the targeting of the growth factor receptors, EGFR-1 and ErbB2, the estrogen nuclear receptor, or the BCR-ABL fusion protein is already part of well established clinical protocols. However, even these ideal tailored therapies fail to provide a long-term cure and can only delay the progression of the disease. Additionally to alterations in bona-fide cancer genes, in a tumor cell, multiple normal regulatory networks have been rearranged in order to adapt to the tumorigenic state. As consequence of this divergence, survival of cancer cells also depends on non-cancer genes that are essential to maintain the tumor homeostasis. This dependency generates tumor specific vulnerabilities that do not exist in normal cells and that represent opportunities for therapeutic intervention. Therefore, we postulate that interfering with these non-cancer dependencies will result in system failure, that is, the cessation of the tumorigenic state. Potential therapeutic agents attacking non-cancer nodes would have a large therapeutic window because of the non-essential nature of the targets in normal cells. Furthermore, in contrast to therapies directed against cancer genes, to escape the lethal effect tumors cells could remove/attenuate the tumorigenic primary lesion (ex. activation of an oncogene) which by itself will affect tumor fitness. Despite the relative superficial similitude among tumors, the specific alterations present in each tumor greatly influence its intrinsic characteristics. Therefore, each cancer genotype will have a distinct series of non- cancer dependencies constituting "genetic synthetic lethals" (GSL). In this application, we plan to identify non- cancer genes that are essential to maintain the viability of tumor cells that carry specific cancer alterations and to explore their potential use as tumor targets for tailored therapies. The systematic elimination of every gene in the genome to search for GSL represents an attractive approach to unveil tumor specific vulnerabilities. Although this process has been successfully applied in yeast to dissect cellular pathways, its use in mammals has been very limited, mainly because of the lack of proper genetic tools. However, recently RNA interference (RNAi) technology has eliminated this handicap. We have pioneered the development of RNAi-based genetic tools that greatly facilitate loss-of-function studies at a genome wide level. Thus, we plan to use our state-of-the-art RNAi-screen technology as a perturbation method to find genes that, when blocked, produce GSL effects in breast cancer cells due to the presence of bona-fide cancer genes. Here, we propose to identify the "Achilles' heel" of breast cancer cells using the novel concept of the "non- cancer addition". Our working hypothesis completely reverses the standard strategy for finding therapeutic cancer targets which has almost exclusively focused in the inactivation of pathways activated in cancer cells. Thus, we are convinced that the successful completion of this research plan will have a considerably impact in the design of the next generation of cancer treatments. PUBLIC HEALTH RELEVANCE: One of the major challenges of modern cancer treatments is the ability to eliminate tumor cells without affecting normal ones. Cancer therapy has radically changed during the last decade. Novel therapies based on the specific molecular changes that drive tumorigenesis in every patient are emerging as low toxic and more efficient alternatives to classical treatments. However, current tailored therapies are suboptimal and, despite some exceptions, their impact in the survival of cancer patients is still modest. Here, we propose to identify this exclusive "Achilles' heel" of breast cancers by eliminating one by one every gene in the human genome to search for genes that, when blocked, exclusively reduce the viability of tumor cells. The successful completion of this research plan will provide us with novel targets for more efficient and less harmful breast cancer therapies and it may impact the design of future generation of cancer treatments.