Inhibitory effect of radiotherapy combined with weekly recombinant human endostatin on the human pulmonary adenocarcinoma A549 xenografts in nude mice

Abstract

The aim of this study was to investigate the inhibitory effect of radiotherapy combined with weekly recombinant human endostatin (RHES) on the human pulmonary adenocarcinoma A549 xenografts in nude mice. The 40 A549 xenograft nude mice models were randomly divided into 4 groups (each group with 10 nude mice). Single radiotherapy group (group 1) was given a single external irradiation (6MV-X ray, 10 Gy) and peritumoral subcutaneous injection of 0.2 ml normal saline every day for 7 days. Single RHES group (group 2) was given peritumoral subcutaneous injection of 0.2 ml RHES (0.75 mg/ml) for 7 days. Combination therapy group (group 3) was given radiotherapy as the same as group 1 and RHES as the same as group 2. Control group was given normal saline as the same as group 1. The tumor volume was smaller in group 3 than in control group from the 8th day after treatment (P<0.05) and tumor regression occurred from the second week after treatment in group 3. On the 15th day after treatment, the inhibitory rates of tumor volume were 69.65%, 92.64% and 116.4% in groups 2, 1 and 3, respectively; MVD number was lower in group 3 than in group 1 (P<0.05); there was no statistical significance in VEGF expression between group 2 and control group as well as between group 3 and group 1 (P>0.05). Apoptosis was marked in group 3. Radiotherapy combined with weekly RHES can significantly inhibit tumor growth and earlier induce tumor regression, which may be related to the improvement of tumor hypoxia and the inhibition of radiation-induced tumor angiogenesis. Short-term application (1 week) of RHES is beneficial to clinical practice.