Molecular Mechanism Of P53-induced Apoptosis In Lung Cancer A549 Cells

Lung cancer is one of the leading causes of cancer-related deaths worldwide.The incidence of lung cancer in China has accounted for 40% of the global incidence of lung cancer,and the incidence of lung cancer is increasing year by year,lung c ancer has become the "first killer" of cancer in China.Similar to other types of cancer,the treatment of lung cancer mainly uses traditional therapies such as surgery,radiotherapy and chemotherapy.However,only 20% to 30% of patients are suitable for surgery.Traditional radiotherapy and chemotherapy have more side effects,which limits the application of traditional therapy.Previous studies have found that p53 gene plays an important role in regulating cell cycle,inhibiting cell growth and inducing apoptosis of cancer cells.p53 gene deletion or mutation was found in 50% of human tumors.In addition,p53 dysfunction is frequently observed in lung cancer,although the resumption of tu mor suppressor function of p53 has recently been recognized as an effective strategy against cancer,but lack of understanding of the molecular mechanisms of lung cancer suppression induced by small molecule-mediated p53 reactivation,limiting p53-based treatment in the application of lung cancer.In the present study,we treated human non-small cell lung cancer A549 cells with two chemically synthesized p53-reactivating compounds,nutlin and RITA,and studied the molecular mechanism of p53-mediated apoptosis of lung cancer cells in order to provide reference for the clinical application of p53 in cancer therapy.The following experiments were carried out in this study:(1)Establishment of an experimental model of A549 cells using two p53 activating compou nds,RITA and nutlin;(2)Using RNA sequencing,we determined the transcriptional profile of hum an non-small cell lung cancer A549 cells after treatment with two p53-activating chemical compounds,nutlin and RITA;(3)Bioinformatics analysis of transcriptional map data to obtain differentially expressed genes;(4)Combined with genome-wide interfering library screening results to predict key factors and signaling pathways that mediate apoptosis and cell cycle inhibition in A549 cells;(5)Functional verification and mechanism studies of predicted key factors and signaling pathways.The results showed that RITA induced apoptosis in A549 cells,while nutlin induced A549 cell cycle arrest.Using RNA sequencing,we obtained the transcriptional profiles of human non-small cell lung cancer A549 cells treated with nutlin and RITA.The next bioinformatics analysis showed that the two compounds,nutlin and RITA,differentially regulated 66 signaling pathways.In order to identify the molecular events involved in the above differential regulatory pathways and different biological effects,we used the genome-wide interference data from Systems Biosciences 200 K sh RNA lentivirus to identify 1294 nutlin-treated synergistic lethal genes in lung cancer cells,and found that these genes were significantly enriched in 19 pathways.Among these pathways,only the two pathways of "adhesive junction" and "axon guidance" are caused by apoptosis of lung cancer cells after p53 reactivation.Functional protein association analysis indicated that GSK3 plays a key role in p53-mediated apoptosis of A549 cells.Further gene function studies have shown that GSK3 inhibition promotes p53-mediated apoptosis in A549 cells in a p53 post-translational activity-dependent manner.In conclusion,this study provides us with new insights into the mechanism of p53-mediated apoptosis of A549 cells,which will contribute to the development of p53-based strategies for lung cancer treatment.