Cell lines and transfection conditions The A549 cell line was purchased from the American Type Culture Collection (ATCC, Manassas, VA, USA). The cells were cultured in RPMI1640 medium (Life Technologies, Bedford, MA, USA) supplemented with 10% fetal bovine serum and 100 U/ml penicillin and 100 U/ml streptomycin. All the Cells were maintained in a humidified atmosphere of 5% CO2 at 37°C. Cell transfection was Wortmannin mw performed using FugeneHD (Roche, Mannheim, Germany) according to the manufacturer’s recommendation. Briefly, A549 cells were seeded in 6-well plates at a density of 3 × 105 cells/well and

cultured to reach 70-80% MS-275 mouse confluence. Two μg plasmid DNA (pshVEGF or pshHK) and 5 μl FugeneHD diluted in serum-free medium were mixed and the complex was added to the cell cultures. Growth medium was used as the control agent. The cells and the supernatants were harvested 48 h after transfection for semiquantitative RT-PCR and ELISA assays. All the transfections were performed in triplicate. Semiquantitative RT-PCR and NF-��B inhibitor ELISA assays Total RNA was extracted from the cells with Trizol Reagent (Invitrogen, Grand Island, NY, USA). RNA concentration was measured by spectrophotometry. RT-PCR was performed with the isolated total RNA (1 μg) using TaKaRa Onestep RNA PCR

Kit (Takara, Japan). β-actin was amplified as the internal control. The primers for VEGF were: forward, 5′-ATC ACG AAG TGG TGA AGT TC-3′; reverse, 5′-TGC TGT AGG AAG CTC ATC TC-3′. The expected sizes of PCR products are 265 bp for VEGF and 512 bp for β-actin [16]. VEGF and β-actin cDNA were amplified by 30 cycles of denaturation for 2 min at 94°C, annealing for 0.5 min at 62°C and extension for

0.5 min at 72°C. After the amplification, each product (10 μl) was loaded on 1% agarose gel for electrophoresis. The amplified products were quantified by Quantity One (Bio-Rad, GNAT2 Richmond, CA, USA). Each experiment was performed in triplicate. Secretion of VEGF into the cell culture supernatant and tumor contents of VEGF in the A549 xenografts were determined using human VEGF ELISA Kit (Jingmei Biotech, Wuhan, China) according to the manufacturer’s instructions. The results of the ELISA assay in the cell culture supernatants were expressed as pg/ml/105 cells. VEGF concentration in the tumors was corrected for total protein. Each experiment was performed in triplicate. Preparation of lipoplexes for in vivo therapy The cationic liposome DOTAP and cholesterol were purchased from Avanti Polar Lipids (Alabaster, AL, USA) and Sigma (St. Louis, MO, USA), respectively. DOTAP:Chol was prepared as described elsewhere [17]. Before tail vein injection, lipoplexes were prepared as follows: 5 μg DNA and 25 μg DOTAP:Chol were diluted respectively in 50 μl 5% GS. The DNA solution was added into the liposome solution dropwisely. The mixture was incubated at room temperature for 30 min prior to injection.