To investigate of relationship between long non-coding RNA CDKN2B-AS1 and idiopathic pulmonary fibrosis coexisting with lung cancer / 中华老年医学杂志

ABSTRACT

Objective:To investigate the role and its mechanism of long non-coding RNA cell cyclin-dependent kinase inhibitor gene CDKN2B-AS1 and its adjacent gene CDKN2A in idiopathic pulmonary fibrosis coexisting with lung cancer.Methods:The cancerous lung tissue specimens and adjacent normal lung tissue specimens were collected from 8 patients with lung adenocarcinoma.The expression level of CDKN2B-AS1 and CDKN2A mRNA were determined by reverse transcription quantitative real-time PCR(RT-qPCR)assays.Pulmonary fibrosis cell model was established by treating human fetal lung fibroblast MRC-5 cell line that was selected as the study object.And the cells were randomly divided into 4 groups: the normal group, the intervention group[induced by transforming growth factou-β(TGF-β1)], the negative siRNA intervention group(induced by TGF-β1 and transfected by nonsense sequence siRNA)and the positive siRNA intervention group TGF-β1 and transfected by siRNA of CDKN2B-AS1). The morphological changes of each group were observed by using the inverted phase contrast microscope after 24 hours intervention.The expression levels of CDKN2B-AS1 and CDKN2A mRNA were determined by RT-qPCR, and the protein amounts of CDKN2A and P53 were measured by Western blotting.Results:The expression levels of CDKN2B-AS1 and CDKN2A mRNA were lower in lung cancer tissue than in adjacent normal lung tissues(2.60±1.33 vs.21.90±19.83, 0.34±0.10 vs.19.83±7.67, t=2.747 and 7.187, P<0.05), which were consistent with the results in IPF.In cell experiments, we observed that TGF-β1 intervention gradually transformed MRC-5 cells from multi-spindled or stellate structures to flattened fibroblasts with varying degrees of differentiation.Compared with the normal group, TGF-β1 intervention group showed that the expression levels of CDKN2B-AS1 and CDKN2A mRNA were significantly decreased(6.80±0.30 vs.56.12±2.46, 9.39±0.37 vs.64.54±3.89, t=47.746 and 33.797, both P<0.001). Compared with the intervention group, the expression levels of CDKN2B-AS1 and CDKN2A mRNA were further decreased in the positive siRNA intervention group(2.38±0.29 vs.6.80±0.30, 2.81±0.36 vs.9.39±0.37, t=4.279 and 4.032, P=0.003 and 0.004), and there was a positive correlation between the mRNA expressions of CDKN2B-AS1 and CDKN2A( r=0.988, P=0.000). Compared with the normal group, the intervention group showed that the protein expressions of CDKN2A and P53 were decreased(3.12±0.06 vs.4.12±0.59, 1.12±0.07 vs.2.11±0.06, t=2.921 and 19.599, P=0.043 and 0.000), and there was a positive correlation between the expression of CDKN2A and P53( r=0.772, P=0.000). Conclusions:Long non-coding RNA CDKN2B-AS1 has a low expression level in both idiopathic pulmonary fibrosis and lung cancer tissues, and it may participate in the P53 pathway by regulating the expression of the neighboring gene CDKN2A, which may be one reason for the high incidence of lung cancer in IPF patients.