NUSAP1 is Upregulated by Estrogen to Promote Lung Adenocarcinoma Growth and Serves as a Therapeutic Target.

Nucleolar and spindle-associated protein 1 (NUSAP1), a microtubule-associated protein, has been recently identified to exhibit aberrant expression patterns that correlate with malignant tumorigenesis and progression across various cancer types. However, the specific regulatory mechanisms and potential targeting therapies of NUSAP1 in lung adenocarcinoma (LUAD) remain largely elusive. In this study, by conducting bioinformatics analyses as well as in vitro and in vivo experiments, we identified that NUSAP1 was significantly upregulated in LUAD, with a notable correlation with poorer overall survival, higher scores for immunogenicity and immune infiltration, as well as increased sensitivity to conventional chemotherapeutic drugs such as paclitaxel, docetaxel and vinorelbine in LUAD. Functionally, NUSAP1 overexpression significantly promoted LUAD cell proliferation, while its knockdown markedly suppressed this process. Interestingly, our results revealed that NUSAP1 upregulation was mediated by estrogen via ERβ activation. Furthermore, we identified entinostat as a novel inhibitor of NUSAP1. Pharmacological targeting ERβ/NUSAP1 axis with fulvestrant (ERβ antagonist) or entinostat (novel NUSAP1 inhibitor) significantly reduced LUAD growth both in vitro and in vivo, which may represent effective alternative therapeutic strategies for patients with LUAD.