Objective: To evaluate the biological effects of tumor suppressor gene p16 on human lung cancer cells with p16 gene deletion.
Methods: p16-pcDNA3 was transfected into lung cancer cell line A549 using lipofectin, in which p16 gene was homozygously deleted. Biological behaviors of the transfected cell line were investigated both in vitro and in vivo. The expressions of p16 mRNA and protein were detected by RT-PCR and immunohistochemistry.
Results: There was stable expression of p16 in the transfected cell line A549. Exogenous p16 gene significantly slowed down the growth of A549 cells as compared with the control. Flow Cytometry showed that the transfected cells were stagnated in G1 phage of cell cycle accompanying with apoptosis. In addition, clonogenic assay showed that the number of colony in soft agar was decreased in transfected cells as well. In vivo, a suppressed tumorigenicity and significantly decreased growth rate were shown in nude mice injected with A549 cells transfected with p16-pcDNA3, as compared with those in mice injected with either original A549 or A549 transfected with pcDNA3.
Conclusion: Exogenous p16 gene can express stably in human lung cancer A549 cell line; exogenous p16 gene transfection induces apoptosis in lung cancer cells with p16 deletion and inhibits growth of the tumor in nude mice.