Mechanism of chemotherapy potentiation of muscle wasting in cancer cachexia

摘要 化疗是大多数癌症的主流治疗方法，尽管最近在开发新的 癌症的治疗方法。一些化疗药物的长期毒性是它们的能力 导致或加剧癌症患者的肌肉萎缩和疲劳，这是恶病质的表现。恶病质 是一种代谢紊乱，是由系统性疾病引起的癌症相关发病率和死亡率的重要原因吗 浪费，以及在增加化疗毒性的同时降低疗效。因此，患者 患有化疗相关肌肉萎缩的患者可能难以坚持或完成 治疗方案，并可能需要延迟治疗，剂量限制，或停止治疗。此外， 化疗相关的肌肉萎缩和疲劳可在停止治疗后持续数月至数年 化疗。因此，化疗和恶病质之间的相互作用是对癌症患者的重大威胁。 生存和生活质量。然而，化疗对癌症的不利影响的潜在机制是 人们对骨骼肌知之甚少，目前还没有FDA批准的这种化疗毒性的治疗方法。 目前的建议旨在通过检验一种新的机制假说来解决这一临床悖论。 氟尿嘧啶(5-FU)和顺铂这两种被广泛处方的化疗药物通过这种药物促进癌症的 在荷瘤小鼠中诱导肌肉萎缩的能力。此前，超治疗剂量的5-FU 研究表明，通过引起线粒体功能障碍，在无癌症动物中直接促进肌肉功能障碍 氧化应激，但不激活介导肌肉蛋白质丢失的泛素-蛋白酶体途径。vt.给出 5-FU用于癌症患者，有必要了解5-FU是否以及如何促进肌肉 在癌症宿主中消耗与治疗相关的剂量。同样，顺铂已被证明能引起肌肉 超治疗剂量的无癌小鼠的直接功能障碍，但它是否以及如何促进肌肉 癌症宿主的消瘦是不确定的。这些知识差距阻碍了化疗的临床干预- 伴发恶病质。根据初步数据，目前的项目旨在检验以下假设：5- 氟尿嘧啶和顺铂通过刺激固有能力间接引起或加剧癌症宿主的肌肉萎缩。 在治疗剂量下诱导肌肉蛋白质降解的癌细胞，并阐明潜在的 这一行动的机制。利用这些发现，将通过改变用途来进行实验性治疗 抑制5-FU和顺铂刺激致癌肌肉能力的现有药理药物 浪费。如果成功，这些药物可以在临床环境中进行快速测试，以进行化疗干预- 伴随的肌肉萎缩。

Summary Chemotherapy is a mainstream treatment for most cancers, despite recent progress in the development of new therapies for cancer. A well-documented long lasting toxicity of some chemotherapy agents is their capacity to cause or intensify muscle wasting and fatigue in cancer patients, which are manifestations of cachexia. Cachexia is a metabolic disorder contributing significantly to cancer-related morbidity and mortality due to systemic wasting, as well as decreasing the efficacy while increasing the toxicity of chemotherapy. Consequently, patients suffering from chemotherapy-related muscle wasting may experience difficulty adhering to or completing treatment regimens and may require delays in treatment, dose limitation, or discontinuation of therapy. Further, chemotherapy-related muscle wasting and fatigue can persist for months to years after the cessation of chemotherapy. Thus, the interplay between chemotherapy and cachexia is a significant threat to cancer patient survival and quality of life. However, the underlying mechanism of the detrimental effects of chemotherapy on skeletal muscle is poorly understood, and there is no FDA-approved treatment for this chemotherapy toxicity. The current proposal aims to address this clinical paradox by testing a novel hypothesis for the mechanism through which fluorouracil (5-FU) and cisplatin, two widely prescribed chemotherapy agents, promote cancer’s capacity to induce muscle wasting in tumor-bearing mice. Previously, supratherapeutic doses of 5-FU were shown to promote muscle dysfunction directly in cancer-free animals by causing mitochondrial dysfunction and oxidative stress but not activating the ubiquitin-proteasome pathway that mediates muscle protein loss. Given that 5-FU is used in cancer patients, it is necessary to understand whether and how 5-FU promotes muscle wasting at therapeutically relevant doses in cancer hosts. Similarly, cisplatin has been shown to cause muscle dysfunction directly in cancer-free mice at a supratherapeutic dose, but whether and how it promotes muscle wasting in cancer hosts are undefined. These knowledge gaps prevent clinical intervention of chemotherapy- associated cachexia. Based on preliminary data, the current project is designed to test the hypothesis that 5- FU and cisplatin cause or intensify muscle wasting in cancer hosts indirectly by stimulating the intrinsic capacity of cancer cells to induce muscle protein degradation at therapeutic doses, and to elucidate the underlying mechanisms of this action. Leveraging these findings, experimental therapies will be carried out by repurposing existing pharmacological agents that inhibit 5-FU and cisplatin’s capacity to stimulate cancer-induced muscle wasting. If successful, these drugs can be quickly tested in clinical settings for intervention of chemotherapy- associated muscle wasting.