Abstract B055: XPO1-dependent nuclear export as a therapeutic target for ALK-positive non-small cell lung cancers

Abstract EML4-ALK fusion has emerged as a significant oncogenic driver in Non-Small Cell Lung Cancer (NSCLC), promoting abnormal cell proliferation and survival. Despite advances with specific tyrosine-kinase inhibitors (TKIs), resistance and relapse still pose significant challenges. Notably, patients with ALK+ NSCLC and co-occurring TP53 mutations experience poorer outcomes after treatment, underscoring an unmet medical need. To anticipate evolving resistance, it is essential to identify and target new vulnerabilities, both on-target and off-target. Exportin 1 (XPO1), a nuclear export protein involved in tumor growth and survival, has emerged as a promising target, and selective XPO1 inhibitors (XPO1i) have been developed. This study evaluates the preclinical efficacy of combining XPO1i with first, second, and third-generation ALK-TKIs in both TKI-sensitive and TKI-resistant NSCLC models. To explore the clinical relevance of XPO1 in ALK+ NSCLCs, we examined its expression in relation to patient survival using data from the Cancer Genome Atlas and Genotype-Tissue Expression datasets. We observed overexpression of XPO1 in tumor tissues, which was positively correlated with a higher risk of disease progression in lung adenocarcinoma. Consistently, patients with low XPO1 expression had significantly better overall survival than those with high XPO1 expression, indicating that elevated XPO1 levels are associated with a poorer prognosis. To investigate the potential vulnerability of ALK+NSCLC to XPO1 inhibition, we tested the XPO1i KPT-330 alone and in combination with ALK-TKIs in various ALK+NSCLC models, including in vitro-generated and patient-derived TKI-resistant cell lines and tumor organoids (PDTOs). Cell viability and proliferation were evaluated using the CellTiter-Glo® assay and the Incucyte Live Imaging system. In vitro, KPT-330 significantly affected cell viability as a single agent and potentiated the antiproliferative effect of ALK-TKIs when combined. Synergy analysis confirmed a synergistic interaction between the two drugs. Cell cycle distribution analysis revealed that XPO1i induced G1 phase arrest, promoting the accumulation of p53, along with a proportional decrease in anti-apoptotic proteins. Notably, KPT-330 demonstrated efficacy regardless of p53 status, inducing apoptosis in both wild-type and mutant cells. ALK+NSCLC cell-derived xenograft (CDX) and PDTO-derived xenograft (PDOXs) mouse models were used to evaluate the efficacy of the combination in vivo. Consistent with in vitro results, the combination of TKIs with KPT-330 displayed enhanced tumor growth inhibition compared to single-agent treatments in ALK+ NSCLC mouse models, indicating its potential to overcome resistance mechanisms and prevent relapse occurrence. Overall, these data support the therapeutic efficacy of XPO1 inhibition, both alone and in combination with ALK-TKIs, in treating ALK+ NSCLCs, despite the development of resistance to targeted therapy and regardless of the patients' p53 mutation status. Citation Format: Maria Vittoria Di Marco, Francesca Picca, Mariantonia Costanza, Enrico Patrucco, Lisa Bonello, Francesca Bersani, Riccardo Taulli, Chiara Ambrogio, Fabrizio Tabbò, Luisella Righi, Aaron Hata, Silvia Novello, Giorgio Vittorio. Scagliotti, Stephan Mathas, Roberto Chiarle, Claudia Voena. XPO1-dependent nuclear export as a therapeutic target for ALK-positive non-small cell lung cancers [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2025 Oct 22-26; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2025;24(10 Suppl):Abstract nr B055.