Experimental Study About The Aromatase Inhibitors On Salivary Adenoid Cystic Carcinoma

Objectives:To investigate the effects of aromatase inhibitor letrozole on adenoid cystic carcinoma ACC-LM cells in nude mice,We establish ACC-LM model through nude mouse to explore anti-tumor effects and mechanism of the aromatase inhibitor so as to provide theoretic basis for further clinical application.Methods:BALB/nu mice were used to establish adenoid cystic carcinoma model by subcutaneously injection of 1×106 adenoid cystic carcinoma cells.Two weeks later,twenty-eight tumor-bearing mice were randomly divided into control group,DMSO group and letrozole group.The number of mice in each group was 8.The control group was given saline injection.The DMSO group was given DMSO O.Olml/kg every other day for two weeks.The letrozole group was given DMSO O.Olml/kg and letrozole 5mg/kg every other day for two weeks.The tumor volumes and weights were observed and measured every three days.Calculating tumor inhibition rate and drawing tumor growth curve after the mice were sacrificed.The apoptosis of tumor tissue was analyzed by flow cytometry.Tumors were collected for HE staining,growth status of tumor were compared among each group.Expression of vascular endothelial growth factor(aromatase)protein in tumor tissue was detected by immunohisto chemistry staining.SPSS 13.0 statistical software was used for statistical analysis.Results:The result of tumor weight and tumor inhibition rate:The weight of the control group,DMSO group and the letrozole group of the tumor were 1.50±0.39g,1.52±0.26g,0.65±0.18g,respectively.The tumor inhibition rate of the letrozole group was 56.67%.The tumor volume of control group and DMSO group increased rapidly,and the letrozole group was relatively slower.The difference was statistically significant(P<0.01).Apoptotic rate of the control group,DMSO group,the letrozole group were 4.6±+1.8,5.7 ±1.5 and 4.2 ±13.6,respectively,the letrozole group with The control group and DMSO group were significantly different(P<0.01).Gray Value results:the control group,DMSO group and the letrozole group were 87.75 ±3.73,88.37±3.85 and 95.88±4.24,respectively.There was significant difference among the control group,DMSO group and the letrozole group(P<0.01).Conclusions:Letrozole can inhibit the proliferation,down-regulate the expression of P450 and promote apoptosis of ACC-LM cells in nude mice.