Depletion of NUAK2 blocks the stemness and angiogenesis and facilitates senescence of lung adenocarcinoma cells via enhancing ferroptosis

NUAK family kinase 2 (NUAK2) has been identified as an important mediator for tumor progression in multiple malignancies. Nevertheless, its role in lung adenocarcinoma (LUAD) remains unclear. Bioinformatic analysis was performed to assess the expression and prognosis of NUAK2 in patients with LUAD. The NUAK2 expression was measured in multiple LUAD cell lines, and the loss-of-function experiment was conducted. Cell proliferation ability was assessed using CCK-8 and colony formation assays. Spheroid formation, alkaline phosphatase (AP) staining, tube formation and SA-β-gal staining assays were performed to examine stemness, angiogenesis and senescence. Lipid peroxidase was assessed by TBARS production and lipid ROS. Western blot was used to detect critical proteins. In addition, A549 cells were treated with ferroptosis inhibitor ferrostatin-1 (Fer-1) for a rescue assay. Finally, A549 cells were subcutaneously injected into the right flank of mice to establish LUAD-bearing mouse model, and the tumor weight and size were detected. NUAK2 was upregulated in patients with LUAD and LUAD cell lines. NUAK2 depletion inhibited cell viability, colonies, tumor spheres and decreased Oct4 and Nanog expression, confirming NUAK2 depletion inhibited proliferation and stemness of A549 cells. Meanwhile, NUAK2 depletion blocked angiogenesis via reducing formed tubes and VEGFR1/2 expression, and promoted senescence of A549 cells by elevating SA-β-gal-positive cells and p16, p21 and p53 expression. Moreover, NUAK2 depletion elevated lipid ROS, TBARS production and Fe2+ level, demonstrating that NUAK2 depletion could trigger ferroptosis in A549 cells. Furthermore, the rescue experiments revealed that the impacts of NUAK2 depletion on malignant behaviors in A549 cells were partly weakened by additional Fer-1 treatment. Finally, in vivo experiments demonstrated that NUAK2 knockdown greatly inhibited tumor growth in LUAD-bearing mice. In summary, NUAK2 depletion impeded oncogenic phenotypes of A549 cells partly via triggering ferroptosis, suggesting NUAK2 as a novel target for treating LUAD.