ANTI-TUMOR MECHANISM OF IL-21 USED ALONE AND IN COMBINATION WITH 5-FLUOROURACIL IN VITRO ON HUMAN GASTRIC CANCER CELLS

To study the effect and related mechanism of IL-21 alone and in combination with 5-Fluorouracil on the proliferation and growth, transferability, and apoptosis of gastric cancer cells, we cultivated gastric cancer cell SGC-7901 and created four experimental groups with varying concentrations of IL-21 and 5-Fluorouracil: IL-21 group (IL-21 100ng/ml), semi-combination group (5-Fluorouracil 25 mu g/ml+IL-21 100ng/ml), 5-Fluorouracil group (5-Fluorouracil 50 mu g/ml), and combination group (5-Fluorouracil 50 mu g/ml+IL-21 100ng/ml). The MTT (3-(4, 5)-dimethylthiahiazo (-z-y1)-3, 5-diphenytetrazoliumromide) assay was used to detect the inhibitory effect of each group on the proliferation and growth of gastric cancer cells. A scratch-wound assay was carried out to detect the inhibitory effect of each group on transferability. TUNEL assay was used to detect the effect of each group on the apoptosis of the gastric cancer cells, and Western blot was used to detect the expression of caspase-3, caspase-8, bcl-2, and c-myc, which are the proteins related to apoptosis, after the drug effect in each group. The results show that, compared to the 5-Fluorouracil group, the inhibitory effects after 24 h of the IL-21 group and the semi-combination group on SGC-7901 were weaker (P<0.001). However, if the effect lasted 48 h, then the inhibition in the semi-combination group had no significant difference compared to the 5-Fluorouracil group (P>0.05). The scarification test showed that all groups could inhibit the transferability of SGC-7901 and that the effect increased successively from the IL-21 group, the semi-combination group, the 5-Fluorouracil group, to the combination group. The TUNEL assay indicated that all groups could promote the apoptosis of SGC-7901. The percentage of cell apoptosis increased, and the Western blot showed that the expression of caspase-3, caspase-8, and c-myc, respectively, in the semi-combination group, the 5-Fluorouracil group, and the combination group increased successively and that the successive increasing of c-myc was the most significant. The expression of bc1-2 tended to decrease. In conclusion, IL-21 used alone and in combination with 5-Fluorouracil are anti-tumor mechanisms in SGC-7901.