Targeting sideroflexin 4, a mitochondrial inner membrane protein involved iniron sulfur cluster biogenesis, to enhance the efficacy of DNA-damaging drugs inovarian cancer

靶向铁弹性蛋白 4（一种参与铁硫簇生物发生的线粒体内膜蛋白），以增强 DNA 损伤药物卵巢癌的疗效

• 批准号: 10304862
• 负责人: FRANK M. TORTI
• 金额: $ 36.76万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10304862
• 关键词: Address; Affect; BRCA1 gene; BRCA2 gene; Biogenesis; Cancer Patient; Carboplatin; Cell Culture Techniques; Cell Death; Cell physiology; Cell-Free System; Cells; Cisplatin; Cytosol; DNA Damage; DNA Repair; DNA Repair Gene; DNA Repair Pathway; Data; Defect; Diagnosis; Drug resistance; Drug usage; Effectiveness; Environment; Enzymes; Epithelial ovarian cancer; Exposure to; FDA approved; Goals; Half-Life; Homeostasis; Inner mitochondrial membrane; Iron; Link; Malignant Neoplasms; Malignant neoplasm of ovary; Mediating; Membrane Proteins; Mitochondria; Mitochondrial Proteins; Mutation; Neoplasm Metastasis; Nucleotide Excision Repair; Oxidative Stress; Pathway interactions; Patients; Pharmaceutical Preparations; Platinum; Platinum Compounds; Poly(ADP-ribose) Polymerases; Prognosis; Proteins; Resistance development; Role; Sulfur; Testing; Time; Woman; anti-cancer; base; cancer cell; cancer stem cell; cancer therapy; chemotherapy; cisplatin-DNA adduct; cytotoxicity; drug development; drug efficacy; experience; experimental study; homologous recombination; improved; in vivo; inhibitor; iron metabolism; knock-down; molecular site; mouse model; mutant; new therapeutic target; patient subsets; protein function; recombinational repair; repair function; repaired; response

ABSTRACT A woman diagnosed today with an ovarian cancer has only a minimally improved chance of long term survival compared to a woman diagnosed 40 years ago. Two different yet related observations may provide an opportunity to improve the outlook of ovarian cancer patients. Both involve DNA damage and repair. 1) The most effective and widely used drugs, the platinum compounds (cisplatin and carboplatin), lose their effectiveness over time – drug resistance develops. An important (but not the only) reason for drug resistance is an acquired ability of ovarian cancers to repair the damage caused by cisplatin DNA adducts. 2) A different class of drugs that induce DNA damage, the PARP inhibitors, has recently been approved by the FDA for patients with DNA repair defects, such as germline or acquired mutations in BRACA1/2. Unfortunately, patients with defects in DNA repair genes represent only a small fraction of ovarian cancer patients. We propose that targeting the mitochondrial protein sideroflexin 4 (SFXN4) may provide a path to addressing both these problems. We discovered that reducing the levels of SFXN4 disrupted Fe-S cluster formation in the mitochondria and cytosol of ovarian cancer cells. We propose that the loss of Fe-S clusters will have major cellular consequences affecting ovarian cancer. First, reduction of Fe-S proteins will increase oxidative stress and DNA damage via the acquisition and redistribution of cellular iron. Second, because critical enzymes involved in NER (nucleotide excision repair) and HRR (homologous recombination repair) require Fe-S clusters for their function and stability, targeting SFXN4 will reduce the activity of DNA these repair pathways. Given the possibility that reduction of SFXN4 could both induce DNA damage and inhibit DNA repair, we further hypothesize that disruption of SFXN4 might enhance the efficacy of platinum-based compounds and expand the effectiveness of PARP inhibitors to ovarian cancers without defects in DNA repair: i.e., render these cancers exquisitely sensitive, like BRCA-mutant cells, to platinum-based drugs and PARP inhibitors. In pilot experiments, we indeed observed that inhibiting SFXN4 1) inhibited DNA repair proteins; 2) enhanced sensitivity to cisplatin; 3) sensitized ovarian cancer cells to PARP inhibitors. We propose three Specific Aims to study the effects of SFXN4 in ovarian cancer. In Aim 1, we explore how and to what extent reduction of SFXN4 increases oxidative stress, limits DNA repair and enhances DNA damage. In Aim 2, we examine the role of targeting SFXN4 in enhancing the effectiveness of both platinum- based compounds and PARP inhibitors in cell cultures and mouse models. In Aim 3 we determine the precise molecular site and mechanism by which SFXN4 functions in Fe-S cluster biogenesis, and directly link this effect to the reduction of DNA repair proteins in NER and HRR pathways. Impact: targeting SFXN4 may represent an opportunity to enhance the efficacy of platinum-based drugs and extend the use of PARP inhibitors to the majority of ovarian cancer patients with normal DNA repair function.

抽象的 今天诊断出患有卵巢癌的妇女只有最小的长期生存机会的机会 与40年前被诊断出的女人相比。两个不同但相关的观察结果可能会提供 改善卵巢癌患者前景的机会。两者都涉及DNA损伤和修复。 1） 最有效，最广泛使用的药物，铂化合物（顺铂和卡铂），失去了 随着时间的推移有效性 - 耐药性发展。耐药性的重要（但不是唯一的）原因 是卵巢癌的可靠能力修复由顺铂DNA加合物造成的损害。 2）与众不同 FDA最近批准了影响DNA损伤的药物类别（PARP抑制剂） DNA修复缺陷的患者，例如种系或BRACA1/2中获得的突变。很遗憾， DNA修复基因缺陷的患者仅占卵巢癌患者的一小部分。 我们建议靶向线粒体蛋白Sideroflexin 4（SFXN4）可能会提供解决方案的途径 这两个问题。我们发现，降低了SFXN4的水平破坏了Fe-S群集的形成 卵巢癌细胞的线粒体和细胞质。我们建议Fe-S簇的损失将有很大 影响卵巢癌的细胞后果。首先，减少Fe-S蛋白会增加氧化应激 和DNA损伤通过对细胞铁的获取和重新分布。第二，因为关键酶 参与NER（核苷酸惊喜修复）和HRR（同类重组修复）需要Fe-S簇 对于它们的功能和稳定性，靶向SFXN4将减少这些修复途径的DNA活性。给出 SFXN4的减少可能诱导DNA损伤并抑制DNA修复的可能性，我们进一步 假设SFXN4的破坏可能会提高基于铂的化合物的效率并扩展 PARP抑制剂对卵巢癌的有效性而没有DNA修复缺陷：即将其渲染 癌症（如BRCA突变细胞）对基于铂的药物和PARP抑制剂完全敏感。在飞行员中 实验，我们确实观察到抑制SFXN4 1）抑制DNA修复蛋白； 2）增强 对顺铂的敏感性； 3）敏感的卵巢癌细胞对PARP抑制剂。 我们提出了三个特定的目的，以研究SFXN4在卵巢癌中的影响。在AIM 1中，我们探讨了如何 SFXN4在多大程度上增加氧化应激，限制DNA修复并增强DNA 损害。在AIM 2中，我们研究了靶向SFXN4在增强两种铂的有效性方面的作用 基于细胞培养物和小鼠模型中的化合物和PARP抑制剂。在AIM 3中，我们确定精度 SFXN4在Fe-S群集生物发生中起作用的分子位点和机制，并直接将其联系起来 NER和HRR途径中DNA修复蛋白还原的影响。 影响：针对SFXN4的靶向可能是提高基于铂的药物效率和的机会 将PARP抑制剂的使用扩展到大多数DNA修复功能正常的卵巢癌患者。