BACKGROUNDVascular endothelial growth factor (VEGF) is known to be one of the most important factors for angiogenesis and tumor cell infiltration. The aim of this study is to determine the influence of phosphorothioate-moeified antisense VEGF oligodeoxynucleotides (ASODN) formulated in cationic liposome on microvessel density (MVD) and VEGF expression of lung cancer.

METHODSLewis lung carcin- oma model was established by subcutaneous injection of Lewis lung carcinoma cells into 40 C57BL/6 mice. Within 24h after inoculation, mice were randomly assigned to four groups treated with ASODN, sense oligodeoxynucleotides (SODN), mismatch oligodeoxynucleotides (MODN), or liposome alone respectively, twice a week for 4 weeks. The weight and volume of subcutaneous tumors were measured. The morphological and ultrastructural changes of tumor cells were observed under microscope and electron microscope. MVD and expression of VEGF protein and VEGF mRNA were detected by immunohistochemical staining and RT-PCR.

RESULTSThe tumor weight in the control group was (7.83±0.78)g, and (4.49±0.43)g in the ASODN group (P < 0.01). The inhibition rate of tumor growth in the ASODN, SODN and MODN groups was 42.6%, 5.1% and 3.2% respectively. MVD and expression of VEGF protein and VEGF mRNA were decreased markedly in the ASODN group compared to the other three groups (P < 0.01).

CONCLUSIONSThe results demonstrate that MVD and VEGF expression of lung cancer can be inhibited by VEGF ASODN injected into tumor tissue in C57BL/6 mice.