Induction of Senescence in Lung Cancer Cells by Qidongning Formula via the Transcription Factor EGR1.

The purpose of this study was to investigate the role of the early growth response gene 1 (EGR1) in inducing senescence in lung cancer cells by Qidongning Formula (QDF). Cell-Counting-Kit-8 was used to study the effect of QDF on A549 and NCI-H1975 cells proliferation. Senescence-associated β-galactosidase (SA-β-GAL) staining was used to examine the effect of QDF on cellular senescence. RT-qPCR analyses and Western blot were used to monitor the expression of EGR1 and the senescence-associated proteins p21 and p53. A rescue assay using an EGR1-overexpressing vector to explore whether EGR1 is a key target gene of QDF-induced lung cancer senescence. Bioinformatics analyses were used to identify the regulatory network involved in the process of QDF-induced senescence in lung cancer cells, downstream of EGR1 activation. QDF could inhibit the proliferation of lung cancer cells in a concentration- and time-dependent manner. SA-β-GAL assay showed that QDF can induce lung cancer cells senescence, an increase in QDF concentration led to a significant increase in the number of cells that stained positive in the SA-β-GAL assay in the group exposed to a higher concentration of QDF. Western blot and RT-qPCR analyses indicated that the expression levels of the p53 and p21 proteins in A549 and H1975 cells increased significantly after QDF intervention. Additionally, EGR1-overexpressing can enhance QDF-induced senescence in lung cancer cells. Bioinformatics analyses revealed the EGR1 target genes implicated in QDF-induced senescence in A549 cells, including 21 senescence-related genes. The present study suggests QDF induces cellular senescence through activation of EGR1 in lung cancer cells and provides an insight for understanding the antitumor mechanisms of this Chinese traditional medicine.