Mechanism Of CUL4A In Bone Metastases Of Non-small Cell Lung Cancer

Background:As the most common malignancy with the highest morbidity and mortality in the world,lung cancer has a trend of increasing year by year.Among them,non-small cell lung cancer(NSCLC)is the most common,accounting for about 85% of lung cancer.Bone tissue is the most common metastatic site for advanced non-small cell lung cancer,and its accompanying series of skeletal-related events(SREs)seriously affect patients’ quality of life.As a member of the cullin protein family,CUL4 A is involved in the ubiquitin-proteasome pathway and is a major component of the multifunctional ubiquitin ligase E3 complex.A large number of studies have confirmed that it is involved in the development of various types of malignant tumors.There are still few reports of this gene in bone metastases of lung cancer.Therefore,exploring the mechanism of action of CUL4 A in bone metastases of non-small cell lung cancer may provide a new therapeutic target for patients with NSCLC.Purpose:1.Screening for genes that may be involved in bone metastases of non-small cell lung cancer based on the results of previous genome-wide sequencing and extensive literature support;2.At the cellular level,the effects of CUL4 A on the biological behavior of NSCLC were verified by in vitro experiments such as clony-forming assay,MTT assay,Transwell,and apoptosis;3.At the animal level,a tumor-bearing mouse model was established by in vivo experiments to further observe the effect of CUL4 A on the ability of NSCLC bone metastases;4.In-depth exploration of the potential molecular mechanisms of CUL4 A in NSCLC bone metastases,providing a new therapeutic target for the diagnosis and treatment of patients with NSCLC bone metastases.Methods:1.According to the results of previous gene sequencing and literature support,the gene related to NSCLC bone metastases was preliminarily selected.Expression of this gene in A549 cells was detected by PCR and Western Blot assays at the RNA and protein levels;2.A549-CUL4 A high-expression cell line was constructed by lentiviral infection.The effects of CUL4 A on the proliferation,migration,invasion and apoptosis of NSCLC were detected by in vitro experiments such as clony-forming assay,MTT assay,Transwell,and apoptosis assay;3.The NOD-SCID tumor-bearing mouse model of A549-CUL4A/NC was constructed by tail vein injection.After about 5 weeks,X-ray film and luciferase in vivo imaging technique were performed to examine the bone metastases of the experimental group and the control group;4.To explore the possible molecular pathways of CUL4 A in bone metastases of non-small cell lung cancer by Western Blot.Results:1.The A549-CUL4 A cell line was successfully constructed at the RNA and protein levels;2.In cell experiments,CUL4 A overexpression can promote the proliferation,migration and invasion of A549 cells,inhibiting their ability to apoptosis;3.In the NOD-SCID tumor-bearing mouse model,the experimental group(A549-CUL4A)mice had more bone metastases than the control group(A549-NC)and the signal was stronger,suggesting that CUL4 A may promote the ability of bone metastasis of A549 cells in vivo;4.CUL4 A may activate ZEB1 by promoting the TGF-β1 pathway,affecting the process of epithelial-mesenchymal transition(EMT),and then promote the development of bone metastases in non-small cell lung cancer.Conclusion:CUL4A can promote the proliferation,migration,invasion and bone metastases of non-small cell lung cancer cells,but inhibit apoptosis.This may be due to the role of CUL4 A in transcriptionally activating ZEB1 by promoting the TGF-β1 pathway,which affects epithelial-mesenchymal transition(EMT).This may provide a new therapeutic target and theoretical basis for the diagnosis and treatment of patients with NSCLC bone metastases.