AG490 regulates JAK2/STAT3 pathway in M2-like macrophages via promoting the proliferation of gastric cancer cells and inhibiting apoptosis / 西安交通大学学报(医学版)

ABSTRACT

【Objective】 To investigate the regulatory effect of JAK2/STAT3 signaling pathway inhibitor AG490 on the functional phenotype of M2-like macrophages and its effects on proliferation, apoptosis, migration, and invasion of gastric cancer cells. 【Methods】 Human mononuclear cell line THP-1 was induced to differentiate into M0 macrophages by PMA in vitro. The M1-like phenotype was induced by LPS and IFN-γ, and M2-like phenotype was induced by IL-4 and IL-13, respectively, and identified by immunofluorescence labeling CD68, CD86 and CD206. The mRNA expressions of CD163, Arg1, CCL22, PPARγ, IL-10, IL-20 and TNF-α were determined by RT-qPCR. The expressions of key proteins in JAK2/STAT3 signaling pathway were detected by Western blotting. M2-like macrophages were treated with JAK2/STAT3 inhibitor (AG490) to observe the expression level of marker genes for M2 like phenotype. Macrophages were co-cultured with gastric cancer cells, and the effects of the macrophages on proliferation, migration, invasion, and apoptosis of gastric cancer cells were detected by CCK-8 method, healing assay, transwell intracellular Matrigel invasion assay, and flow cytometry. The xenograft tumor model of MKN45 gastric cancer in nude mice was prepared, and the tumor size and quality were observed for 20 days after the model was established. 【Results】 THP-1 cells were induced into M1-like macrophages and M2-like macrophages. M1-like marker (CD86) and M2-like marker (CD206) were identified by flow cytometry. The P38MAPK, JAK2, p-STAT3/STAT3 protein levels of M2-like macrophages treated with AG490 were significantly reduced. The mRNA expression levels of Arg1, CCL22, PPARγ and IL-10 were significantly reduced in the group of M2-like macrophages treated with AG490. Co-culture of M2-like macrophages with gastric cancer cells could promote gastric cancer cell viability, increase migration and invasion ability, and inhibit apoptosis. When the group of M2-like macrophages treated with AG490 was co-cultured with gastric cancer cells, the proliferation activity of MKN-45 cells and MGC823 was significantly lower than that in M2 group (1.047±0.062 vs. 1.426±0.076, 1.149±0.006 vs. 1.301±0.015). Compared to M2 group, the migration (100.0%±5.73% vs. 72%±3.85%) and invasion ability (100.0%±7.40% vs. 60%±6.54%) of MGC823 gastric cancer cells in AG490 treatment group were significantly reduced. The apoptosis rate of MGC823 cells in the AG490 treated group was significantly higher than that in M2 group (27.51%±0.70% vs. 20.82%±0.92%). In the nude mouse xenograft tumor model, the volume and weight of the transplanted tumor collected at day 20 were significantly lower in AG490 treated group than in M2 group (736.04±182.34 vs. 1 080.5±250.57)mm3, (0.64±0.11 vs. 0.87±0.17)g. 【Conclusion】 AG490 downregulates the activation level of JAK2/STAT3 signaling pathway in M2-like macrophages, inhibits M2-type polarization, partially reverses the cancer-promoting function of M2-like macrophages, inhibits proliferation, migration and invasion of gastric cancer cells, and induces apoptosis. The JAK2/STAT3 signaling pathway can be further studied as a potential therapeutic target for gastric cancer.