Abstract: ObjectiveTo study the inhibitory effect of cellular Fas-associated death domain-like interleukin-1 beta converting enzyme inhibitory protein(c-FLIP)antisense oligodeoxy nucleotides(ASODN)on transplantation tumor of lung cancer cell line A549 in nude mice.MethodsThe nude mice bearing A549 cancer cells were applied to detect the effect of c-FLIP-ASODN in vivo.Control group,liposome group,sense oligonucleotide(SODN)group were set for comparison.The grow th curve of transplantation tumor was draw n and inhibition ratio was calculated according to tumor weight.Immunohistochemistry was used to examine the expression of c-FLIP and Ki-67 antigen of the transplantation tumor.RT-PCR was used to examine the expression of c-FLIP mRNA.Terminal deoxynucleotidyl transferase mediated uridine triphosphate(UTP)nick end labeling(TUNEL)was used to examine the apoptosis index of the transplantation tumor.ResultsThe transplantation tumor of ASODN group developed slowly after the treatment.The tumor volume and the tumor weight of ASODN group were 512.4±33.6 and 376.9±45.8 mm³ and were smaller than those of the control group with a tumor inhibiting rate of 64.31%.The expression of c-FLIP mRNA and protein,Ki-67 antigen of ASODN group were 0.30±0.05,19.54±6.36,and 25.71±5.42,respectively,lower than those of the control group.The apoptosis index of the transplantation tumor of ASODN group was 39.68±6.28 and higher than that of the control group,with statistically significant difference(P<0.05).Conclusionc-FLIP-ASODN has anticancer activity on lung cancer cell line A549 in vivo.The inhibition in vivo is related to the decreased expression of c-FLIP mRNA and protein and increased apoptosis of the cancer cell.