Abstract: Objective To investigate the expression of insulin-like growth factor binding protein 1 (IGFBP-1) in human gastrointestinal stromal tumors, and its effect on the growth of gastrointestinal stromal tumor cells as well as its underlying mechanism. Methods The expression of IGFBP-1 was detected by immunohistochemical staining.The human gastrointestinal stromal tumor cells GIST882 were transfected with siRNA-NC (siRNA-NC group) and siRNA-IGFBP-1 (siRNA-IGFBP-1 group), respectively, and blank control group was set. The mRNA and protein expression level of IGFBP-1 were detected by qRT-PCR and the Western blot; the cell viability was detected by the CCK-8 experiment; the cell proliferation ability was detected by the EDU test; the cell apoptosis was detected by Annexin V-FITC/PI staining; the cell migration and invasion ability was detected by Transwell chamber experiment, and the expression of PI3K/AKT/mTOR signaling pathway-related proteins was detected by the Western blot. Results The positive expression rate of IGFBP-1 in gastrointestinal stromal tumor tissues was higher than that in adjacent tissues (P<0.05). Compared with the blank control group and the siRNA-NC group, the relative expression of IGFBP-1 mRNA and protein in siRNA-IGFBP-1 group were decreased (all P<0.05). After IGFBP-1 silencing, the cell proliferation activity decreased, the EDU positive cells rate decreased, the apoptosis rate increased, and the number of migrating and invading cells decreased (both P<0.05); and the ratios of p-PI3K/PI3K, p-AKT/AKT and p-mTOR/mTOR decreased (all P<0.05). Conclusions Silencing IGFBP-1 expression can inhibit the cell proliferation, migration, invasion of gastrointestinal stromal tumor, and promote cell apoptosis, which may be related to the inhibition of PI3K/AKT /mTOR signal pathway activation.

Key words: Gastrointestinal stromal tumor, Insulin-like growth factor binding protein 1, Proliferation, Apoptosis, Migration, Invasion