To explore whether gastric cancer cell acts on macrophages through lncRNA Hotair to and convert them into cancer supporting cells, and promote the invasion and proliferation of gastric cancer cell.

The experiment was divided into the control group and AGS cells co-culture group. Co-culture experiment was conducted to detect the phenotypic transformation of macrophages. In situ hybridization was performed to co-localize M2-type macrophages with lncRNA. Key lncRNAs promoting phenotypic transformation of macrophages were detected and screened by RT-PCR. LncRNA levels of gastric cancer cells were knocked down and co-cultured by RNA interference. Subsequently, CCK-8 assay and Transwell assay were used to detect the effect of transformed cancer-related macrophages on the proliferation and invasion ability of gastric cancer cells. Analysis of variance and t test were used for statistical analysis.

The results of co-culture experiment showed that compared with the control group (5.63±1.97) , AGS cell group contained more CD206⁺ m2-type cancer-related macrophages (32.51±5.44) , and the difference was statistically significant (t = 25.742, P = 0.001) . ELISA also showed that macrophages in AGS cell group secreted more anti-inflammatory factors [TGF-β (163.45±54.91) pg/ml, control group: (87.32±19.24) pg/ml; il-4: (156.83±69.25) pg/ml, control group: (49.94±17.55) pg/?ml; il-10: (385.65±24.75) pg/ml, control group: (98.82±46.26) pg/ml], the difference between the two groups was statistically significant (t = 7.167, 8.203, 29.991, P < 0.05) . Hotair was screened as the key lncRNA through the GEO database and RT-PCR, and subsequent RNA interference experiments showed that the knockdown of Hotair inhibited the transformation of macrophages (the number of CD206 positive cells changed from 41.12±6.91 to 21.45±2.19) , thus reducing the proliferation and invasion ability of gastric cancer cells.

LncRNA Hotair of gastric cancer cells will be absorbed by macrophages and transformed into cancer-related macrophages, thereby promoting the proliferation and invasion ability of gastric cancer cells.