Effect of Weikangning on gastric cancer cell growth and expression of vascular endothelial growth factor and its receptors KDR and Flt-1

Effects of NM-3-containing serum on endothelial growth factor and its receptors KDR and Flt-1 in human gastric cancer SGC-7901 cell line

AIM: To study the inhibitory effect of anti-angiogenesis agent NM-3-containing serum on human gastric cancer SGC-7901 cell line.

METHODS: Human gastric cancer SGC-7901 cell line was cultured with high, medium and low doses of NM-3-containing serum, and two control groups were cultured with medium alone and medium with serum. Cell cycle distribution and apoptosis rate were determined by flow cytometry. After 72 hours incubation, mRNA for vascular endothelial growth factor (VEGF) and its receptors, including KDR and Flt-1, was detected by reverse-transcriptase polymerase chain reaction (RT-PCR).

RESULTS: The apoptosis rate in the high- (25.20% ± 0.86%, 43.62% ± 3.53%, 54.35% ± 5.42%) and medium-dose (16.80% ± 0.40%, 26.95% ± 3.25%, 39.85% ± 4.10%) groups was significantly increased compared with that in the two control groups were cultured with meduim alone (5.34% ± 0.28%, 6.91% ± 1.06%; 6.87% ± 1.24%) and meduim with serum (5.66% ± 0.72%, 8.90% ± 0.86%, 8.06% ± 0.78%) after 6, 24 and 72 hours culture. The apoptosis rate was increased with prolongation of incubation time and NM-3 dose. The apoptosis rate in the high-dose group was higher than in the medium and low dose groups (P < 0.05). After 72 hours in the high-dose group, the proportion of cells in G₀/G₁ phase was higher, and the number in S, G₂/M phase was lower than that in the medium- and low-dose groups. There were significant differences between the proportion of cells in G₀/G₁, S and G₂/M phase in the high- and medium-dose groups and the two control groups (P < 0.01). mRNA of VEGF and its receptors KDR and Flt-1 decreased in SGC-7901 cells in the high-, medium- and low-dose NM-3 groups after 72 hours. Compared with the two control groups, the high-dose group significantly inhibited mRNA transcription for VEGF and its receptors KDR and Flt-1 (P < 0.01), and the medium- and low-dose groups obviously inhibited mRNA transcription (P < 0.05).

CONCLUSION: NM-3-containing serum can inhibit vascular formation in gastric carcinoma, and can induce apoptosis of human gastric carcinoma cells.

Effect of Ezhu on expression of cyclooxygenase, vascular endothelial growth factor and prostaglandin E2 in human gastric cancer cell line SGC7901

AIM: To investigate the effect of Ezhu on the expression of cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF) and prostaglandin E₂ (PGE₂) in human gastric cancer cell line SGC7901.

METHODS: The MTT method was used to observe the suppression of the human gastric cancer (SGC7901) cells treated with Ezhu. By drawing the suppression rate curves, we selected the appropriate Ezhu concentration at the 25% proliferation suppression rate as experimental concentration. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were adopted, respectively, to examine the expression of COX gene and protein. Furthermore, ELISA method was used to detect the variation of the VEGF and PEG₂ expression in culture medium.

RESULTS: Ezhu definitely inhibited the proliferation of human gastric cancer cells in a concentration dependent manner. Electrophoresis of the RT-PCR products demonstrated the expression of COX-1 and COX-2 gene in the human gastric cancer cells. Gray scale analysis showed that both Ezhu and celecoxib inhibited the expression of COX-1 and COX-2 gene, and the inhibitory action of Ezhu was greater than celecoxib. However, Western blot clearly showed that a specific protein strip was observed in COX-1 group at the 70 kDa, while in COX-2 group at the 80 kDa. Gray scale analysis confirmed than both Ezhu and celecoxib had apparent suppression on COX-2 protein, but had no effect on COX-1. Moreover, the suppression function of Ezhu surpassed celecoxib. Ezhu and celecoxib obviously degraded the content of VEGF in gastric cancer cells. In comparison with those in the control group, the results are statistically significant (91.0 ± 18.2, 127.8 ± 12.1 ng/L vs 162.0 ± 15.1 ng/L, P < 0.01). The level of PGE₂ in the cells treated with celecoxib was lower than the control group with no statistical significance. Nevertheless, Ezhu decreased the level of PGE₂ significantly (67.5 ± 6.9 ng/L vs 78.7 ± 5.6 ng/L, P < 0.01).

CONCLUSION: Ezhu can inhibit COX-2 and its downstream expression of PGE₂, and down-regulates VEGF expression, so as to suppress the proliferation of gastric cancer cells.

Inhibitory effect of antisense vascular endothelial growth factor RNA on the profile of hepatocellular carcinoma cell line in vitro and in vivo

AIM: To evaluate the effect of antisense vascular endothelial growth factor (VEGF) RNA (PCMV-FGEV) transfection on the profile of hepatocellular carcinoma (HCC) SMMC-7721 cells in vitro and in vivo.

METHODS: SMMC-7721 cells were transfected with PCMV-FGEV antisense, PCMV-VEGF sense and empty vector plasmid encapsulated by lipofectamine as antisense group, sense group and control group respectively. The positive cell clones were selected with G418. The stable transfection and expression of VEGF in the cells were determined by RT-PCR and immunohistochemistry. Cell proliferation was observed by MTT assay. FACS analysis was used to determine the effect of PCMV-FGEV transfection on cell apoptosis. The growth of transfected cells in vivo was also observed in nude mice.

RESULTS: VEGF expression was reduced in SMMC-7721 transfected with PCMV-FGEV, which was confirmed by RT-PCR and immunohistochemistry. No effect of PCMV-FGEV transfection was found on cell proliferation and cell apoptosis of SMMC-7721 in vitro. The growth of cells transfected with PCMV-FGEV was slow in nude mice and accompanied with obvious apoptosis. The latent time of tumors in the antisense group was 25.0 ± 1.8 d, which was longer than that in sense and control groups (F = 19.455, P < 0.01). The average tumor weight in antisense group (0.96 g ± 0.28 g) was the smallest among the three groups (F = 21.501, P < 0.01).

CONCLUSION: The expression of VEGF can be inhibited by antisense PCMV-FGEV. Antisense PCMV-FGEV has no effect on cell proliferation and apoptosis of SMMC-7721 in vitro but can inhibit tumor growth and induce cell apoptosis in vivo.