Dual-inhibition of NAMPT and PAK4 induces anti-tumor effects in platinum-resistant ovarian cancer by suppressing mitochondrial function and expression of genes related to inflammation and DNA repair.

Ovarian cancer follows a characteristic progression pattern, forming multiple tumor masses enriched with cancer stem cells (CSCs) within the abdomen. Most patients become resistant to standard platinum-based drugs, necessitating a change in treatment approach. To target CSCs, inhibiting NAMPT, which is the rate-limiting enzyme in the salvage pathway for NAD+ synthesis, has been explored. KPT-9274 is an innovative drug targeting both NAMPT and PAK4. However, its effectiveness against ovarian cancer had 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 expression of inflammation and gene repair-related genes. Moreover, by altering PAK4's mostly cytoplasmic localization, the compound hindered kinase activity, leading to decreased phosphorylation of S6 Ribosomal protein, AKT, and β-Catenin in the cytoplasm and its suppression was NAD+- dependent. These findings suggest that KPT-9274 could be a promising treatment for ovarian cancer patients resistant to platinum drugs, emphasizing the need for precision medicine to identify the specific NAD+-producing pathway a tumor relies on before treatment.