FOXP3对乳腺癌血管形成的影响及其分子机制研究

Breast cancer is a common female malignancy, angiogenesis is closely related to the occurrence of tumor development and the elucidation the molecular mechanism of angiogenesis is significant. Our team and the foreign study found: FOXP3 is a suppressor gene in breast cancer which can inhibit breast cancer proliferation and metastasis. Is FOXP3 relevant with the breast cancer angiogenesis? Our previous study found : ① the tube formation assay initially confirmed FOXP3 can inhibit breast cancer angiogenesis; ② the microarray analysis suggest FOXP3 can regulate the expression of VEGF; ③ the FOXP3 binding sites exist the promoter of VEGF by bioinformatics analysis ; ④ the Dual-Luciferase reporter gene experiments confirmed that FOXP3 can inhibit VEGF promoter activity; ⑤ the over expression of FOXP3 in breast cancer cell can decrease the expression of VEGF; ⑥ the small clinical breast cancer specimens suggest that the expression of FOXP3 was negatively correlated with VEGF. Based on the results of preliminary experiment and literature research,We planed to elucidate the function of FOXP3 in the breast cancer angiogenesis through epidemiological studies of large-scale breast cancer samples, cytological research, and animal models and illustrate the the role and molecular mechanisms of FOXP3 in the breast cancer angiogenesis.This study provides a new target for the treatment of breast cancer.

乳腺癌是女性常见恶性肿瘤，血管形成与肿瘤发生发展密切相关，阐明血管形成分子机制意义重大。课题组和国外研究发现：FOXP3能够抑制乳腺癌增殖和转移，是乳腺癌的抑制基因。那么FOXP3与乳腺癌血管形成是否相关呢？课题组前期研究发现：①小管形成实验初步证实FOXP3能够抑制乳腺癌血管形成；②基因芯片的差异筛选结果提示FOXP3能够调控VEGF的表达；③生物信息学分析VEGF启动子上存在FOXP3结合位点；④初步双荧光素酶报告基因实验证实FOXP3能够抑制VEGF启动子活性；⑤乳腺癌细胞中过表达FOXP3能够下调VEGF的表达；⑥小规模临床乳腺癌标本中FOXP3与VEGF呈表达负相关。本课题拟在此基础上，通过系统临床分析、体外细胞行为学及体内动物实验系统明确FOXP3在乳腺癌血管形成中的功能；系统探讨FOXP3抑制乳腺癌血管形成的作用及其分子机制。本研究为乳腺癌临床治疗提供新靶位。

乳腺癌是女性常见恶性肿瘤，血管形成与肿瘤发生发展密切相关，阐明血管形成分子机制意义重大。文献提示：FOXP3能够抑制乳腺癌增殖和转移，是乳腺癌的抑制基因。课题组前期研究发现：①小管形成实验初步证实FOXP3能够抑制乳腺癌血管形成；②基因芯片的差异筛选结果提示FOXP3能够调控VEGF的表达；③生物信息学分析VEGF启动子上存在FOXP3结合位点；④初步双荧光素酶报告基因实验证实FOXP3能够抑制VEGF启动子活性；⑤乳腺癌细胞中过表达FOXP3能够下调VEGF的表达；⑥小管形成实验和出芽实验证实FOXP3是通过调控乳腺癌VEGF的表达抑制乳腺癌血管生成；⑦小规模临床乳腺癌标本中FOXP3与VEGF呈表达负相关。.本项目首先分析FOXP3对乳腺癌血管生成相关基因的调控作用，发现FOXP3能够调控多种血管生成相关基因的表达。收集乳腺癌临床样本进行免疫组化实验，结果显示FOXP3与肿瘤血管密度呈负相关。.收集不同乳腺癌细胞的条件培养基，进行HUVEC小管形成实验和出芽试验，发现FOXP3过表达乳腺癌细胞的条件培养基促进HUVEC小管形成及出芽能力显著降低。构建动物模型，对实验组肿瘤组织进行FOXP3与CD31的免疫组化实验。上述体内外实验证实FOXP3抑制乳腺癌血管形成。.通过双荧光素酶报告基因检测FOXP3对VEGF启动子的调控作用，发现FOXP3能够抑制VEGF启动子活性；ChIP实验检测FOXP3与VEGF启动子的结合能力，发现FOXP3通过直接结合于VEGF启动子区域发挥调控作用。重复HUVEC小管形成实验和出芽试验，发现添加VEGF因子可消除FOXP3对HUVEC细胞小管形成和出芽能力的抑制作用，以上结果证实FOXP3通过抑制VEGF启动子活性进而抑制VEGF在乳腺癌中的表达，且FOXP3通过抑制VEGF的表达抑制乳腺癌血管生成。.综上所述，本研究首次发现FOXP3能够抑制乳腺癌血管形成；证实FOXP3通过抑制VEGF的表达抑制乳腺癌血管生成。本研究为乳腺癌临床治疗提供新思路。.