Endostar combined with cryoablation for subcutaneous xenografted tumor model of lung adenocarcinoma cell line A549 in BALB/c nude mice: An experimental study

Abstract

Objective To investigate the inhibitory effect of Endostar combined with cryoablation on lung adenocarcinoma cell line A549 in BALB/c nude mice, and to discuss its interaction mechanisms.Methods The lung adenocarcinoma A549 model in BALB/c nude mice were established. When the largest diameter of tumor reached 1.0 cm, a total of 24 mice were randomly and equally divided into 4 groups:control group, Endostar group, cryoablation group and cryoablation plus Endostar group. The largest diameter and the vertical diameter of the tumors were measured at different points of time after treatment. At the 21st day, the mice were sacrificed and the tumors were removed and the rate of tumor cell apoptosis, the microvessel density(MVD) and the expression level of vascular endothelial growth factor(VEGF) were determined by using immunohistochemistry method. The results were statistically analyzed. Results The tumor growth velocity of the control group, Endostar group, cryoablation group and cryoablation plus Endostar group was(236.68 ± 51.23)%,(220.02 ± 30.61)%,(159.46 ± 29.33)% and(103.34 ± 25.50)%,respectively(P 0.01). The rate of apoptosis of the four groups was(21.67 ± 2.34)%,(22.17 ± 1.47)%,(38.33 ± 1.37)% and(49.17 ± 1.72)%,respectively(P 0.01). The MVD and the expression levels of VEGF of the cryoablation plus Endostar group were significantly lower than those of the other three groups(P 0.01). Statistical analysis revealed that a positive correlation existed between the express of VEGF and MVD. Conclusion Endostar can obviously enhance the therapeutic efficacy of cryoablation on lung adenocarcinoma A549 in BALB/c nude mice. The underlying mechanisms may be the Endostar-inhibited angiogenesis through down-regulating the expression of VEGF, and the cooperative effect of Endostar and cryoablation on the promotion of tumor cell apoptosis.