FGFR1促进乳腺癌细胞生长和转移的机理及其靶向治疗的生物医学意义

The breast cancer incidence among Chinese women is sharply increasing. However, the research and therapeutic development have been historically delayed in China versus the developed Western countries. Facing this daunting challenge, we need to devote greater efforts to the basic, translational and clinical studies of breast cancer in China. Identification of new diagnostic and prognostic markers and drug targets for breast cancer will be very useful for improving the prognostic quality and developing new breast cancer therapies. In this program, we will investigate the expression profiles of FGFR1 protein and its role in breast cancer growth and metastasis in Chinese women. We will determine whether FGFR1 overexpression can be used as a poor prognostic marker and whether FGFR1 is a molecular target for inhibiting the growth of breast cancer with FGFR1 overexpression. Specifically, we first plan to select a specific FGFR1 monoclonal antibody to examine FGFR1 expression levels in tumor sections of a large Chinese breast cancer cohort. The obtained results will be analyzed in correlation with clinical patient data to determine the frequency of FGFR1 overexpression and its associations with tumor grades, metastasis, recurrence and disease-free survival time. Furthermore, we will generate breast cancer cell lines expressing inducible FGFR1 activity and use breast cancer cell culture models and mouse models to investigate how FGFR1 activation promotes breast cancer cell growth, migration, invasion and metastasis. We also will test whether switching off FGFR1 activity will arrest or regress primary and metastatic breast cancer cell growth and metastasis.

我国乳腺癌的迅速增加和乳腺癌研究与治疗的相对滞后迫切需要加快乳腺癌的基础、转化和临床研究。其中，鉴定新的诊断标志物和治疗靶点将提高乳腺癌患者的预后评估水平并有助于开发新的乳腺癌治疗药物。本课题拟通过研究FGFR1蛋白在中国乳腺癌患者中的表达及其促进乳腺癌生长和转移的细胞与分子机理，确定FGFR1高表达能否作为不良预后的分子标志物和能否采用FGFR1作为抑制乳腺癌生长的分子靶点。首先，本研究将筛选FGFR1抗体对400例乳腺癌组织进行免疫组化染色、评分，并结合病人的临床资料分析FGFR1在各型乳腺癌中的表达水平与频率以及对病人预后评估的临床意义。其次，本课题将建立具可调控FGFR1活性的细胞株和动物模型来深入探讨FGFR1在乳腺癌生长、发展、转移和治疗中的重要作用。最后，本课题还将应用多种分子生物学方法来鉴定FGFR1调控的关键基因并阐明这些基因在FGFR1促进乳腺癌细胞生长中的作用与机理。

通过研究FGFR1蛋白在乳腺癌患者中的表达及其促进乳腺癌生长和转移的细胞与分子机理，为乳腺癌的诊断和治疗提供潜在的分子标志物和治疗靶点。.首先，建立和完善了人乳腺癌组织FGFR1的免疫组化检测方法和组织芯片平台，制备组织芯片33个。FGFR1、A20(TNFAIP3)和FOXQ1蛋白在乳腺癌、癌旁、远癌和纤维瘤中的阳性率分别为7.76%(59/733)、10.87%(51/469)、7.25%(55/759)、0.56%(1/177)；29.2%(211/722)、9.7%(58/599)、8.7%(13/149)、9.3%(35/379)和56.54%(108/191)、77.51%(162/209)、84.91%(135/159)和9.3%(12/25)。结合临床资料分析显示FGFR1表达水平与Her2呈负相关(p=0.045)，与ER阳性或PR阳性或三阴性(ER-/PR-/HER2-)无明显相关性，FGFR1高表达与病人生存/预后呈负相关(p=0.022)且更易复发。A20表达与ER呈负相关(P=0.017)。其次，建立了iFGFR1稳定转染的乳腺导管癌细胞株DCIS.COM+iFGFR1和相应的动物模型。AP20187可激活该细胞及动物模型中的iFGFR1信号通路进而促进细胞增殖和成瘤能力。DCIS-iFGFR1细胞中iFGFR1激活促进ERK1/2活性、EMT、细胞增殖和DCIS-iFGFR1细胞在小鼠体内的生长和浸润性进展并改变与细胞增殖、迁移、癌症途径、其他分子和细胞功能相关的基因表达谱。最后，鉴定出FGFR1调控的关键基因13个，深入研究TNFAIP3和FOXQ1基因。iFGFR1激活上调TNFAIP3 依赖于ERK2。TNFAIP3基因敲除可抑制AP20187诱导/不诱导的DCIS-iFGFR1细胞增殖和肿瘤生长。iFGFR1激活促进DCIS.COM细胞增殖、乳腺微球生长、肿瘤生长和进展时需要TNFAIP3。iFGFR1激活促进ERK1/2活性、细胞增殖、迁移和肿瘤生长需要FOXQ1。.综上，FGFR1可能通过调控TNFAIP3、FOXQ1来促进乳腺癌细胞增殖、迁移和DCIS形成及进展，可能是预后不良的标志。TNFAIP3、FOXQ1可能是FGFR1信号促进DCIS生长和进展的潜在靶点，为乳腺癌的治疗和预后评估提供实验依据。