Lutein Inhibits Tumor Progression Through ATR/CHK1/p53 Signaling Pathway In Non-small Cell Lung Cancer

Cancer is a major public health problem worldwide and has become a serious threat to human lives.According to the global cancer statistics in 2020,lung cancer is one of the most commonly diagnosed cancer and the leading cause of cancer death all over the world.Non-small cell lung cancer(NSCLC)accounts for about 85% of all lung cancer cases with a low five-year survival rate which has not been improved for several decades.Among several valuable treatment strategies,chemotherapy still remains the standard first-line treatment for advanced NSCLC.Due to the resistance and toxicity of chemotherapeutic agents,it is increasingly urgent to discover novel anti-tumor drugs with potent efficacy for NSCLC.Lutein,a member of carotenoids,has been reported to exert toxic and anti-tumor effects on several tumor cells,such as breast cancer and prostate cancer cells.However,the detailed functions of lutein in NSCLC have been few reported and the underlying mechanisms are still elusive.Objectives: To investigate the anti-tumor effects of lutein in vivo and in vitro and the underlying molecular mechanisms in NSCLC.Methods: Human NSCLC cells A549 and SPC-A1 were treated with 0.1% DMSO or different concentrations of lutein in vitro.Assays detecting cell proliferation,cell cycle distribution and cell apoptosis were performed to investigate the anti-tumor activities of lutein,including CCK8,colony formation,Ed U staining and flow cytometry assays.RNA sequencing(RNA-seq)analysis was used to recognize differentially expressed genes(DEGs)and signaling pathways between the control group and lutein group in A549 cells.Target m RNAs and proteins involved in the anti-tumor effects of lutein were detected by q RCR and Western blotting.Comet assay was used to detect DNA damage in NSCLC cells.Subcutaneous xenograft models in nude mice were established with A549 cells to investigate the tumor inhibition effect of lutein in vivo.Results: lutein significantly inhibited the cell proliferation,arrested cell cycle at G1 phase and induced the apoptosis of NSCLC cells in a dose-dependent manner.RNA-seq analysis recognized that p53 signaling pathway was significantly upregulated in lutein-treated NSCLC cells.Western blotting assay detected the activation of ATR/CHK1/p53 signaling pathway.Moreover,ATR inhibitor and p53 silence treatment rescued lutein-induced tumor inhibition.DNA damage assays showed that lutein induced DNA damage of NSCLC cells in a dose-dependent manner.In vivo,lutein impeded the tumor growth and prolonged the survival of xenograft tumor mice.Conclusion: Our study reveals that lutein inhibits tumor progression of NSCLC through DNA damage-induced activation of ATR/CHK1/p53 signaling pathway.Accordingly,lutein is a potential candidate for clinical NSCLC treatment.