Inhibitory effect of arsenic trioxide on human carcinoma of breast cells transplanted in nude mice

Objective To explore the antitumor effect of arsenic trioxide on human carcinoma of breast cell strain MDA-MB-435 s transplanted in nude mice.Methods To set up the model of ER negative breast cancer of nude mice with MDA-MB-435 s xenografts;to randomly divided 24 female BALB/C-nu/nu nude mice with tumor into four groups:normal saline group,cisplatin group,low dose arsenic trioxide group(1.5 mg/kg),high dose arsenic trioxide group(3.0 mg/kg).To comparison the role of the tumor growth inhibition of each group,and to detection the expressions of PCNA and Caspase-3 induced by arsenic trioxide examined by immunohistochemical method.Resluts These treatment groups can significantly inhibit the tumor growths,and make the tumor volumes and the weights significantly less than those of the control group(P＜0.05).The immunohistochemical staining showed that:in control group,the expression of Caspase-3 protein positive cells decreased,and the expression of PCNA protein positive cells increased;In treatment group,the expression of Caspase-3 protein positive cells increased,and the expression of PCNA protein positive cells decreased.There are significant differences in the expressions of Caspase-3 protein and PCNA protein positive cells between treatment group and control group(P＜0.05).Conclusions Arsenic trioxide may inhibit the tumor growths by decreasing the expression of PCNA protein and increasing the expression of Caspase-3 protein,and in a dose-dependent manner. Key words: Arsenic trioxide; Carcinoma of breast; DDP; Generation; Apoptosis