Ovarian cancer follows a characteristic progression pattern, forming multiple tumor masses enriched with cancer stem cells (CSCs) within the abdomen. Most patients develop resistance to standard platinum-based drugs, necessitating better treatment approaches. Targeting CSCs by inhibiting NAD+ synthesis has been previously explored. Nicotinamide phosphoribosyltransferase (NAMPT), which is the rate limiting enzyme in the salvage pathway for NAD+ synthesis is an attractive drug target in this pathway. KPT-9274 is an innovative drug targeting both NAMPT and p21 activated kinase 4 (PAK4). However, its effectiveness against ovarian cancer has not been validated. Here, we show the efficacy and mechanisms of KPT-9274 in treating 3D-cultured spheroids that are resistant to platinum-based drugs. In these spheroids, KPT-9274 not only inhibited NAD+ production in NAMPT-dependent cell lines, but also suppressed NADPH and ATP production, indicating reduced mitochondrial function. It also downregulated of inflammation and DNA repair-related genes. Moreover, the compound reduced PAK4 activity by altering its mostly cytoplasmic localization, leading to NAD+-dependent decreases in phosphorylation of S6 Ribosomal protein, AKT, and β-Catenin in the cytoplasm. These findings suggest that KPT-9274 could be a promising treatment for ovarian cancer patients who are resistant to platinum drugs, emphasizing the need for precision medicine to identify the specific NAD+ producing pathway that a tumor relies upon before treatment.

卵巢癌遵循一种特征性的进展模式，在腹部形成多个富含癌症干细胞（CSC）的肿瘤块。大多数患者会对标准铂类药物产生耐药性，因此需要更好的治疗方法。之前已经探索过通过抑制 NAD+ 合成来靶向 CSC。烟酰胺磷酸核糖转移酶 (NAMPT) 是 NAD+ 合成补救途径中的限速酶，是该途径中一个有吸引力的药物靶点。KPT-9274是一种针对NAMPT和p21激活激酶4（PAK4）的创新药物。然而，其对抗卵巢癌的有效性尚未得到验证。在这里，我们展示了 KPT-9274 在治疗对铂类药物耐药的 3D 培养球体方面的功效和机制。在这些球体中，KPT-9274 不仅抑制 NAMPT 依赖性细胞系中 NAD+ 的产生，而且还抑制 NADPH 和 ATP 的产生，表明线粒体功能降低。它还下调炎症和 DNA 修复相关基因。此外，该化合物通过改变 PAK4 的主要细胞质定位来降低 PAK4 活性，导致细胞质中 S6 核糖体蛋白、AKT 和 β-Catenin 磷酸化的 NAD+ 依赖性降低。这些发现表明，KPT-9274 可能是对铂类药物耐药的卵巢癌患者的一种有前途的治疗方法，强调需要精准医学在治疗前确定肿瘤所依赖的特定 NAD+ 产生途径。