Abstract: Background and purpose: Emerging evidence suggests that fat cell-derived cytokine leptin, which is closely related to obesity, plays an important role in carcinogenesis and tumorigenesis. In this study, the effect of leptin on the invasion and migration abilities of GBC-SD and OCUG cells were observed in vitro, and its possible related mechanisms were explored. Methods: GBC-SD and OCUG cells were divided into control group and experimental group. In the experimental group, we used small interfering RNA (siRNA) to target and silence the expression of leptin in GBC-SD and OCUG cells. Real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR) was used to detect the transfection efficiency. Wound healing assay and transwell assay were used to detect the migration and invasion abilities of GBC-SD and OCUG cells. The immunofluorescence and immunocytochemistry experiments were used to detect the expression of leptin protein in GBC-SD and OCUG cells after siRNA interference. The protein expressions of leptin and p-AKT in GBC-SD and OCUG cells after interference were detected by Western blot. Results: The results of wound healing assay showed that the migration abilities of GBC-SD and OCUG cells decreased after silencing leptin with siRNA interference (t=26.614, P ＜ 0.01; t=19.338, P ＜ 0.01). The results of transwell migration assay also showed that the migration abilities of GBC-SD and OCUG cells decreased after silencing leptin with siRNA interference (t=7.185, P=0.002; t=8.889, P=0.003). Transwell invasion assay results showed that the invasion abilities of GBC-SD and OCUG cells decreased after interference (t=10.183, P=0.001; t=9.697, P=0.001). Immunofluorescence and immunocytochemistry experiments showed decreased leptin protein expression in GBC-SD and OCUG cells after interference. Western blot showed that leptin and p-AKT protein expressions were down-regulated after targeted silencing in GBC-SD cells (t=26.463, P ＜ 0.01; t=13.904, P ＜ 0.01). Western blot showed that leptin and p-AKT protein expressions were also down-regulated after targeted silencing in OCUG cells (t=21.335, P ＜ 0.01; t=17.914, P ＜ 0.01). Conclusion: Down-regulation of leptin expression in GBC-SD and OCUG cells can inhibit cell invasion and metastasis, and may regulate gallbladder cancer invasion and migration through AKT signaling pathway. Leptin are expected to become an important target for gallbladder cancer treatment.

Key words:  Gallbladder cancer, Leptin, Invasion, Migration