*2.7. Quantitative RT-PCR*

Total RNA extraction and quantitative real-time PCR analysis was performed as previously described [36,38]. The following primers were used: VEGFR1 forward primer 5 -GAGCTAAAA ATCTTGACCCACATTG-3 , reverse primer 5 -CAGTATTCAACAATCACCATCAGAG-3 ; endoglin forward primer 5 -TGGTACATCTACTCGCACACGC-3 , reverse primer 5 -GGCTATGCCATGCTG CTGGTGG-3 ; and endogenous reference gene β-actin was detected using forward 5 -TGCCGACAGGATGCAGAAG-3 , reverse primer 5 -GCCGATCCACACGGAGTACT-3 . The samples were measured three times and a final result was inferred by averaging the data. The values are presented as mean ± S.E.M of the means obtained from three independent experiments.

#### *2.8. Scratch Migration Assay*

The ЕA.Hy926 cells migration study of was performed as described previously [37,39]. siRNA/L1 complexes were prepared as described above at N/P ratios of 8/1 and 16/1 in quadruplicates (siRNA concentration was 200 and 100 nM). Also, we used a combination of different siRNA in the complexes. Stained cells were photographed using an AxioObserver Z1 microscope (Carl Zeiss, Jena, Germany). Three random fields were registered. EA.Hy926 cell migration during the wound repair was analyzed using ImagePro Plus 6.0 software (Media Cybernetics, Bethesda, MD, USA). Number of cells (n) that migrated to the wound area was counted. Cell density (ρ) was counted in area of 17,000 μm2. Relative number of migrated cells was computed by (n/n')\*(ρ'/ρ), where n' is number of migrated cells in untreated control and ρ' is the cell density in the untreated control. The results are presented as mean± S.E.M of the means obtained from five independent experiments with four samples.

## *2.9. Proliferation Assays*

For the сell proliferation study, 0.6 <sup>×</sup> 104 ЕA.Hy926 cells in 100 <sup>μ</sup>L DMEM-F12 medium per well were plated in a 96-well plate. siRNA/L1 complexes were prepared as described above at N/P ratios of 8/1 and 16/1 in quadruplicates (siRNA concentration was 200 and 100 nM). Also, we used a combination of different siRNA in the complexes. The cell culture medium was replaced with 50 μL of medium without FBS. siRNA/peptide complexes were added and incubated with cells for 2.5 h.Then, the cell culture medium was replaced with 100 μL of medium containing 2.5% FBS. After 72 h incubation, the cell proliferation was analyzed using Alamar blue or crystal violet staining. In the case of AlamarBlue assay, cells were incubated in a normal culture medium with 10% Alamar blue for 2 h. The fluorescence was recorded on a Wallac 1420D scanning multilabel counter (Thermo Fisher Scientific Oy, Vantaa, Finland) with an excitation wavelength at 544 nm and emission wavelength at 590 nm.In the case of crystal violet analysis, cells were stained in 100 μL of 0.2% crystal violet in 5% methanol and were then dried. Cells were dissolved in 100 μL of 50% acetic acid per well for 5 min.Absorbance was measured at 540 nm and at 630 nm. The 630 nm values were subtracted from the 450 nm values to correct for optical imperfections in the microplate. The results are shown as mean±S.E.M of the means obtained from five independent experiments with four samples.
