Expression Of Retinoic Acid Receptor β Mediates Retinoic Acid-induced Growth Arrest And Apoptosis In Lung Cancer Cell Line A549 And The Research Of Proteome

Objective: To investigate the role of RARβ in regulating the proliferation, differention, apoptosis of the lung cancer celland to explore the mechnism of retinoic acid.Methods: we used expression vector (pcDNA3.0) to introduce the human RARβ gene into lung adenocarcinoma cell line A549 in which the expression of RARβ was down-regulated. To detect the status of apoptosis. the morphological change was observed, the flow cell machinery was used to detect the cell cycle, DNA fragments and MTT were used, Meanwhile we used RT-PCR to detect the expression of RARβ, cdk4, cyclinDl and p53 gene. Two-dimensional gel electrophoresis with immobilized pH gradient was used to separate the differential proteomic expression. After silver staining , they were analyzed by software.Results: The results in apoptosis cells showed cell shrinkage, loss of adhesion and nuclear condensation; the rate of apoptosis was 65.8%; DNA fragments occured. RT-PCR showed that the expression level of RARβ was higher, the level of p53 had no change and the level of cdk4 and cyclinDl was lower. The average deviations of spot position were 2. 97±0. 34mm in IEF direction and 2. 73±0.45mm in SDS-PAGE direction, respectively. The average number of spots was 1354±86 in A549, 1738±79spots in HELF and987±64spots in RARβ-A549. There were 893 spots in A549 matched HELF, 329 spots in A549 and445 spots in HELF not be matched each other. There were 634 spots in A549 matched RARβ-A549, 520 spots in A549 and205 spots inRARP—A549 not be matched each other. The differencesbetween A549 and HELF, and between A549 and RAR ft — A549 were bothsignificant (K0. 05) through one-way ANOVA.Conclusion: 9-cis-retinoid acid induced the apoptosis of the lung cancercell lines by RARPover-expression; the cooperation of 9-cis-retinoidacid and RAR3 down-regulated the expression of cdk4 and cyclinDlsignificantly; 9-cis-retinoid resulted in apoptosis of the cells thatexpress the normal p53 not mutated p53.Significance: We researched the apoptosis of A549 transfected with theRARP gene, which provided the theoretical basis for clinicaldifferentiational therapy of lung cancer using retinoic acid.The differences between A549 and HELF, and between A549 and RARP —A549 could provide the basis of the theory about retinoic acid to be usedin clinical and about early diagnosis and therapy of lung cancer.