Targeting colorectal cancer stem cells with ALDH1B1 antagonists

结直肠癌是世界上第三大最常见的恶性肿瘤，约有140万新发病例 每年有70万人死亡到2030年，全球发病率预计将上升60%，因为西方饮食和 生活方式变得越来越普遍，越来越多的年轻人患上结直肠癌。尽管 预防性筛查和监测，大约20%的结直肠癌患者在 早期患者40 - 50%在治疗后会复发。不幸的是， 癌症治疗如抗有丝分裂剂、表皮生长因子受体拮抗剂和血管生成抑制剂 对晚期疾病基本无效。因此，这些患者的5年生存率仅为12%。 现在人们普遍认为，消除癌症干细胞（CSC）是持久临床反应的关键， 这些自我更新的细胞驱动肿瘤复发、化学抗性和转移。我们的项目努力实现这一点 通过研究和靶向结肠直肠癌CSC特有的代谢途径来实现这一目标。 我们的工作建立在最近的报道，醛脱氢酶1B1（ALDH 1B1）在肠干细胞中表达， 并且是结肠癌来源的球状体培养物和异种移植物生长所需的。我们的研究结果支持了一个角色， ALDH1B1在结肠直肠CSC维持中的作用，我们已经开发出第一个已知的ALDH1B1选择性拮抗剂。 我们还解决了ALDH1B1和ALDH1B1-抑制剂复合物的第一个X射线晶体结构，揭示了ALDH1B1-抑制剂复合物的结构。 拮抗剂作用的分子基础，并获得进一步化合物开发的见解。我们最新的线索 化合物可以抑制结肠直肠癌球状体的活力，对粘附培养物或非粘附培养物的影响最小。 癌细胞此外，我们的初步研究表明，ALDH 1B1抑制剂可以抑制结肠的生长， 小鼠的异种移植肿瘤。 我们现在正在研究ALDH1B1促进结直肠癌的机制（目的1）。我们将 探索这种线粒体酶在结直肠CSC维持、化疗耐药性和 侵袭性，使用代表各种结肠直肠癌亚型的细胞系。我们还将确定 是否致癌ALDH1B1功能涉及视网膜和/或脂质过氧化产物的氧化，我们将 阐明ALDH1B1依赖性转录组。在进行这些机制研究的同时，我们将使用药物 化学、生物化学测定和细胞模型，以开发具有优化效力、选择性 和药理学性质（目的2）。然后，我们将评估ALDH1B1抑制剂在结直肠癌中的活性 异种移植模型（Aim 3）。总之，这些研究将加深我们对ALDH1B1功能的理解， 结肠直肠CSC生物学。他们还将产生新的化学工具，用于研究ALDH1B1依赖性途径， 揭示了药理学ALDH1B1抑制的治疗潜力，并提供了有价值的线索， 开发ALDH1B1靶向药物。

Colorectal cancer is the third most common malignancy in the world, with approximately 1.4 million new cases and 700,000 deaths each year. Global incidence rates are expected to escalate 60% by 2030 as Western diets and lifestyles become more common, and colorectal cancer is afflicting increasing numbers of young adults. Despite preventative screening and surveillance, approximately 20% of colorectal cancer patients have metastatic disease at the time of diagnosis, and 40-50% of early-stage patients will relapse after treatment. Unfortunately standard colorectal cancer therapies such as anti-mitotic agents, epidermal growth factor receptor antagonists, and angiogenesis inhibitors are largely ineffectual against late-stage disease. As a result, the 5-year survival rates for these patients is only 12%. It is now widely believed that eliminating cancer stem cells (CSCs) is the key to durable clinical responses, as these self-renewing cells drive tumor relapse, chemoresistance, and metastasis. Our project strives to achieve this goal by investigating and pharmacologically targeting metabolic pathways that are unique to colorectal cancer CSCs. Our work builds on recent reports that aldehyde dehydrogenase 1B1 (ALDH1B1) is expressed in intestinal stem cell and required for the growth of colon cancer-derived spheroid cultures and xenografts. Our findings support a role for ALDH1B1 in colorectal CSC maintenance, and we have developed the first known ALDH1B1-selective antagonists. We have also solved the first X-ray crystal structures of ALDH1B1 and ALDH1B1-inhibitor complexes, uncovering the molecular basis of antagonist action and gaining insights for further compound development. Our latest lead compounds can inhibit the viability of colorectal cancer spheroids, with minimal effects on adherent cultures or non- cancerous cells. In addition, our preliminary studies indicate that ALDH1B1 inhibitors can suppress the growth of colon cancer xenografts in mice. We are now investigating the mechanisms by which ALDH1B1 promotes colorectal cancer (Aim 1). We will explore the potential roles of this mitochondrial enzyme in colorectal CSC maintenance, chemoresistance, and invasiveness, using cell lines that are representative of various colorectal cancer subtypes. We will also determine whether oncogenic ALDH1B1 function involves the oxidation of retinal and/or lipid peroxidation products, and we will elucidate the ALDH1B1-dependent transcriptome. In parallel with these mechanistic studies, we will use medicinal chemistry, biochemical assays, and cellular models to develop ALDH1B1 inhibitors with optimized potency, selectivity, and pharmacological properties (Aim 2). We will then evaluate the activities of ALDH1B1 inhibitors in colorectal cancer xenograft models (Aim 3). Together, these investigations will deepen our understanding of ALDH1B1 function and colorectal CSC biology. They will also generate new chemical tools for studying ALDH1B1-dependent pathways, reveal the therapeutic potential of pharmacological ALDH1B1 inhibition, and provide valuable leads for the development of ALDH1B1-targeting drugs.