The Interrelationship Between the Apoptosis of L78 Cell-line of the Lung Cancer and It's Expression of Rb, Cyclin D 1 Gene Protein Induced by 9-cis-retinoic Acid

ObjectiveTo investigate the interrelationship between the apoptosis of L78 cell-line of the lung squamous cell carcinoma and it's expression of Rb, Cyclin D 1 gene proteins induced by 9-cis-retinoic acid and to evaluate it's mechanism.MethodsL78 cell-line of the lung squamous cell carcinoma was incubated in vitro and radomly divided into two groups. Experiment group: 5μmol/L 9-cis-retinoic acid( 9-cis RA) was added; control group:0.1% Dimethylsulfoxid was added as a control. After 48 hours incubation, the Rb gene protein expression of L78 cell-line was estimated by immunohistochemistry method; the Rb, the Cyclin D 1 gene proteins and the cell apoptosis were estimated by flow cytometry, and the correlation among them was studied.ResultsThe expression of Rb gene was enhanced,the Cyclin D 1 decreased prominently, and the cancer cell apoptosis increased in experiment group than those of control group (P0.01). There was positive correlation between the expression of Rb gene and the rate of cancer cell apoptosis (r=0.854, P0.05), negative correlation between the expression of Cyclin D 1 gene and the rate of cancer cell apoptosis(r=-0.812, P0.05). ConclusionsThe growth of cancer cells is arrested at G 0/G 1 stage by the way that 9-cis RA can increase the expression of Rb gene and decrease the Cyclin D 1 and simultaneously induce the apoptosis of L78 cell-line of the lung cancer.