| Objective:To study the effect of leptin receptor(Ob-R)antagonists on tumor growth and metastasis of thyroid cancer nude mouse xenograft model by thyroid cancer nude mouse lung metastasis model.Methods:Fifteen female BALB/c nude mice aged 3-4 weeks were randomly divided into blank group(NC group),experimental group(Allo-aca group)and calorie restriction group(CR group)after adaptive feeding for 1 week.After anesthetized nude mice,0.1 mL of 5×106/0.1 mL of TPC-1 cell suspension was injected into nude mice through tail vein.The NC group was left untreated,the Allo-aca group was subcutaneously injected with the Ob-R antagonist Allo-aca(1 mg/kg/day)every day,and the CR group was given 85%of the daily dietary intake of the other two groups.The weight and general physical condition of the mice were monitored every 2-3 days.Eight weeks after TPC-1 inoculation,nude mice were sacrificed by CO2 inhalation,and the lung tissue of each nude mouse was dissected and blood was collected.The number of nodules on the surface of the lung tissue was grossly observed,and the size of the tumor was observed under a microscope after HE staining of the lung tissue.The concentrations of T3,T4 and TSH in serum were determined by nude mouse ELISA kit.Results:Vitro experiments:① The invasion,migration,proliferation and cell viability of TPC-1/BCPAP were increased after ADSCs-CM intervention.The effect of ADSCs-CM on the invasion and migration of TPC-1/BCPAP was much greater than that on the proliferation.② ADSCs-CM can up-regulate the expression of Ob-R and MMP-2 in papillary thyroid cancer cells.③ The effect of ADSCs-CM on promoting invasion and migration was significantly decreased after neutralizing some leptin using leptin neutralizing antibody(NAB),but there was no significant effect on cell viability.In addition,leptin neutralizing antibody can antagonize the increase of MMP-2 level.Animal experiment:① Number of tumors:3.6 in the NC group,1.8 in the Allo-aca group and 2.2 in the CR group.The number of metastatic lung nodules decreased in the Allo-aca and CR groups,with a significant decrease in the Allo-aca group,and the difference was statistically significant(P<0.050).② Average tumor diameter:308.4 μm for NC,134.8 μm for Allo-aca,and 236.0 μm for CR.The mean diameter of tumors was significantly reduced in the Allo-aca group(P<0.0001).③Serum T3,T4,TSH concentrations:The average T3 concentration in Allo-aca group was about 1.27 times that in NC group(P<0.05),and the average T3 concentration in CR group was not statistically significant compared with NC group.Compared with NC group,serum T4 level was increased and TSH level was decreased in Allo-aca group and CR group,but these were not statistically significant.④Body weight of nude mice:From the second week,the body weight of CR group was significantly lower than that of NC group(P<0.01),and there was no significant difference between Allo-aca group and NC group.Conclusion:ADSCs up-regulates the expression of leptin receptor in TPC-1/BCPAP by secreting leptin,promotes the expression of MMP-2,and further promotes the invasion,migration and proliferation of TPC-1/BCPAP cells.Leptin neutralizing antibody can attenuate the effects of ADSCs-CM on the invasion,migration and proliferation of TPC-1/BCPAP.Blockade of leptin effects by Ob-R antagonists can reduce the number and diameter of metastatic pulmonary nodules. |
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