STAT3诱骗寡核苷酸激活巨噬细胞抗乳腺癌免疫反应

An oligonucleotide decoy for STAT3 activating immnne response of macrophages to breast cancer

目的探讨肿瘤相关巨噬细胞(TAMs)的信号转导和激活子3(STAT3)信号途径在抗乳腺癌免疫应答中的作用。方法用大鼠乳腺癌细胞的培养上清液诱导培养大鼠的腹腔巨噬细胞,再用STAT3诱骗寡核苷酸(decoy ODNs)抑制其STAT3的活性并用细菌的脂多糖将其激活,检测其对肿瘤细胞的杀伤活性和抗原呈递能力;将乳腺癌细胞移植到SD大鼠,然后接受诱导的巨噬细胞或转染STAT3 decoy ODNs的诱导巨噬细胞的处理,检测肿瘤的生长和大鼠的免疫反应强度。结果伴随STAT3的过度激活,诱导的巨噬细胞对肿瘤细胞的细胞毒性和抗原呈递能力减弱。 STAT3 decoy ODNs增强诱导的巨噬细胞的杀伤活性,与对照组比较,差异有统计学意义(P< 0．01);增强诱导的巨噬细胞的抗原呈递能力,巨噬细胞呈递抗原刺激的淋巴细胞的增殖能力、IFN- γ产量及细胞毒性与对照组比较,差异有统计学意义(P值均<0．01)。STAT3活性被抑制的巨噬细胞能增强大鼠对移植乳腺癌的免疫反应而抑制肿瘤的生长,在第24、28、32天,STAT3 decoy ODNs 处理组的肿瘤体积与其他各组比较,差异有统计学意义(P值均<0．01)。结论 TAMs的免疫抑制作用可能与其STAT3信号过度激活有关,抑制其STAT3信号能增强机体对乳腺癌的免疫应答反应。

Objective To evaluate roles of signal transducer and activators of transcription 3 （STAT3） signaling of tumor-associated macrophages （TAMs） in rat immune response to breast cancer. Methods Rat peritoneal macrophages were incubated with supernatant of cultured rat breast cancer cells and STAT3 activity was analyzed. The macrophages were transfected with STAT3 decoy oligonucleotides （ODNs） and then were stimulated bylipopolysaccharide （LPS）. Cytotoxicity and antigen-presenting ability of the cells were evaluated. In addition, SHZ-88 cells were implanted into rats treated with maerophages activated STAT3 or macrophages disrupted STAT3 activity. Rats were assessed for tumor growth and immune response. Results Induced with supernatant of cultured breast cancer cells and activated with LPS, the macrophages displayed a reduction of cytotoxicity and antigen-presenting function companied by over-activated STAT3. But transfection with STAT3 decoy oligonucleotides enhanced cytotoxicity of the macrophages （P 〈 0.01 ） and antigen presenting-function of the cells （proliferation, IFN-γ production and cytotoxicity of T cells activated by the macrophages were significantly increased, all P〈 0.01 ）. Furthermore, injection induced macrophages promoted tumor growth companied by immune unresponse in the rat tumor models, but injection induced macrophages transfected with STAT3 decoy oligonucleotides led to retarded tumor growth （at 24th, 28th and 32nd day, tumor volumes in treat group were decreased significandy, all P 〈 0.01） companied by immune activation. Conclusion Immunosuppressive activities of TAMs may be correlated with over-activated STAT3 signaling of the cells and disruption of STAT3 activity of TAMs can enhance rat immune response to breast cancer.