Evidence for p53 Expression as a Target for Lung Cancer Early Diagnosis

Abstract

Obiective: To study the change of p53 expression in BEAS-2B cells malignant transformation process, and detect the role of p53 expression for lung cancer early diagnosis. Method: BEAS-2B cells acute expose NNK at 500 μg/ml for 24 hours, and these cells (BEAS-2BNNK cells) were subcultured continuously in vitro, Biological characteristics and ultrastructure of them were studied with Colony formation assay and electron microscopy. The change p53 expression of BEAS-2B cells were detected by immunohistochemical method. Results: The serum resistance was appeared in the 5th passage of BEAS-2BNHK cells and these cells could not grow into tumor in nude micei¼›The plating efficiency of the 15th passage of BEAS-2BNNK cells in soft agar (0.032%) increased 13.9 fold Compared with that of control group cells(0.0023%)P<0.001, the cells had the biological characteristic of transformation cells but could not grow into tumor in nude mice; The 25th passage of BEAS-2BNNK cells could grow into tumor in nude micei¼›The tumor cells were confirmed cancer cells by histopathology. The ultrastructrure also showed that BEAS-2BNNK cells were Transformed into cancer cells. p53 expression of BEAS- 2B cells were 10.7 ± 2.3%, but p53 expression of the 5th passage of BEAS-2BNNK cells were 43.3 ± 5.7%, the 15th passage of BEAS-2BNNK cells were 73.8 ± 5.2%, the 25th passage of BEAS-2BNNK cells were 92.4 ± 6.5%. The 5th,15th, 25th passage BEAS-2BNNK cells.VS. p53 expression of BEAS-2B cells, P<0.001. Conclusion: The model of malignant transformation of BEAS-2B cells induced by NNK(500 μg/ml) established successfully. The change of biological characteristic and ultrastructure indicated that the malignant transformation of BEAS-2BNNK cell is a Chronic, multiple-step development process. p53 overexpression appeared early stage in BEAS-2BNNK cells which did not change into cancer cells. It indicated that p53 expression would be as a target for lung cancer early diagnosis, and it was beneficial to early-warning and mass screening of lung cancer in high-risk smoking population.