KLF5通过TNFAIP2调控乳腺癌细胞的增殖、迁移和侵袭

KIZ OpenIR > 科研部门 > 肿瘤生物学（陈策实）

	KLF5通过TNFAIP2调控乳腺癌细胞的增殖、迁移和侵袭
其他题名	KLF5 regulates breast cancer cell proliferation, migration and invasion through TNFAIP2
	贾琳
学位类型	博士
导师	陈策实
	2015-10
学位授予单位	中国科学院研究生院
学位授予地点	北京
关键词	Klf5 Tnfaip2 Rac1 Cdc42 迁移侵袭乳腺癌
其他摘要	乳腺癌是全球女性中最普遍和死亡率最高的癌症。在不同的国家和地区，乳腺癌的发病率存在差异。西方发达国家和地区较发展中国家而言，具有更高的乳腺癌检出率和发病率。在我国，乳腺癌发病率和死亡率近年来都持续快速上升，并且呈现年轻化趋势。乳腺癌是非常容易发生浸润和转移的恶性肿瘤，发生远端转移的乳腺癌病人的存活率很低。因此，研究乳腺癌发病的分子机理对于提高乳腺癌的治愈率和治疗效果具有重要的意义。 KLF5是一个重要的转录因子，能和许多基因启动子上的GC盒结合并调控其转录。KLF5在细胞内具有多种重要的功能，如促进细胞增生，细胞周期，细胞凋亡，分化，血管新生以及干细胞自我更新等。许多研究证据表明，KLF5的异常表达与结肠癌、乳腺癌、前列腺癌和膀胱癌等的发生相关。在乳腺癌中，KLF5在高级别、低分化和基底型三阴性乳腺癌中高表达，并且KLF5 mRNA高表达预示乳腺癌病人预后差，生存时间短。TNFAIP2是一个TNFα直接诱导表达的基因，广泛存在于内皮细胞，造血细胞和成熟的精子中，与细胞的多种功能相关，如血管生成、精子形成、抗病毒反应、细胞凋亡以及细胞间纳米管形成等。TNFAIP2在鼻咽癌临床样本中高表达，并与肿瘤的远端转移有关。在本研究中，我们揭示了TNFAIP2是一个KLF5直接调控的下游靶基因，KLF5至少部分通过TNFAIP2实现其调控乳腺癌细胞生长、迁移和侵袭的功能。首先,在乳腺上皮细胞系，包括三阴性乳腺癌细胞系中，KLF5和TNFAIP2共表达。在mRNA和蛋白水平上，KLF5和TNFAIP2的表达呈显著的正相关性。TCGA数据库的大量乳腺癌临床样本统计结果也进一步证实TNFAIP2和KLF5的表达高度相关，并且TNFAIP2在ER/PR/HER2三阴性肿瘤中显著高表达。进一步的研究发现，操控KLF5的表达可改变TNFAIP2的表达水平。双荧光素酶报告基因实验（Dual Luciferase assay）、染色质免疫共沉淀（ChIP）和生物素标记的寡核苷酸共沉淀（Oligo Pull-down）实验结果共同表明KLF5直接与TNFAIP2的启动子区域的Sp1位点结合，调控TNFAIP2的启动子的活性，进而调控TNFAIP2的转录水平。其次，在乳腺癌中，TNFAIP2与KLF5一样，同样扮演原癌基因的角色，具有促进三阴性乳腺癌细胞生长和增殖、非贴壁软琼脂克隆形成以及移植瘤的生长的功能。KLF5至少部分通过TNFAIP2，实现其对三阴性乳腺癌细胞生长和增殖的调控。而且，KLF5和TNFAIP2还具有调控三阴性乳腺癌细胞粘附、迁移和侵袭的功能。KLF5通过TNFAIP2调节三阴性乳腺癌细胞的形态和肌动蛋白骨架，进而调控细胞的粘附、迁移和侵袭。此外，TNFAIP2能与Cdc42和Rac1间接或直接相互作用，调控这两个小GTPase的活性。KLF5和TNFAIP2通过活化Cdc42和 Rac1，重塑细胞骨架，促进乳腺癌细胞的生长、迁移和侵袭。通过药物抑制Cdc42 或Rac1的表达或活性，可靶向KLF5-TNFAIP2-Rac1/Cdc42信号通路，从而抑制三阴性乳腺癌细胞的增殖。综上所述，这些研究表明KLF5 和TNFAIP2在乳腺癌中共表达,并且KLF5直接与TNFAIP2的启动子结合并紧密调控TNFAIP2的转录。KLF5部分通过TNFAIP2调控乳腺癌细胞的增殖、迁移和侵袭。TNFAIP2与两个小GTPase （Rac1 和 Cdc42 ）相互作用并调节其活性，从而调控细胞形态和肌动蛋白骨架。KLF5和TNFAIP2通过Rac1 和 Cdc42促进乳腺癌细胞的增殖、迁移和侵袭。因此，KLF5和 TNFAIP2是潜在的有价值的三阴性乳腺癌诊断预后标志物和药物治疗靶标。; For women worldwide, breast cancer is the most common cancer diagnosed and has the highest death toll. The incidences of breast cancer are different in different countries and regions. Western countries show higher rates of breast cancer screening and incidence compared to developing countries. In China, the incidence and mortality rates of breast cancer have continued to rise rapidly and the patient age becomes younger and younger in recent years. Breast cancer is a malignant tumor very prone to invasion and metastasis, the survival rate of patients with distant metastasis is very low. Therefore，the studies of molecular mechanism of breast cancer have great significance for improving the cure rate and treatment effect of breast cancer.KLF5 (Kruppel-like factor 5) is a basic transcription factor binding to GC boxes at a number of gene promoters and regulating their transcription. KLF5 participates in mutiple biological process including cell proliferation, cell cycle, apoptosis, differentiation, angiogenesis and stemness. Many results showed that aberrant expression of KLF5 contributes to colon cancer, breast cancer, prostate cancer and bladder cancer and so on. In breast cancer, KLF5 transcription factor is highly expressed in high-grade, poorly differentiated and basal-like triple negative breast cancer (TNBC). High levels of KLF5 mRNA expression indicate shorter disease-free survival and overall survival for patients with breast cancer.TNFAIP2 is a TNFα-inducible primary response gene. TNFAIP2 is widely expressed in endothelial cells, hematopoietic cells, and mature sperm. It plays multiple roles in angiogenesis, spermatogenesis, antiviral responses, apoptosis and tunneling nanotube formation. TNFAIP2 is highly expressed in nasopharyngeal carcinoma cells compared with adjacent normal tissues, and TNFAIP2 expression is significantly correlated with distant tumor metastasis. In this study, we revealed that TNFAIP2 is a direct KLF5 target gene, and KLF5 promotes beast cancer cell proliferation, migration and invasion in part through TNFAIP2.First, KLF5 and TNFAIP2 are co-expressed in breast epithelial cell lines, including TNBC. TNFAIP2 is highly correlated with KLF5 at both mRNA and protein expression level in these cell lines. The statistics from TCGA database also indicated TNFAIP2 expression significantly correlates with KLF5 expression in breast cancer specimens and the expression of TNFAIP2 is significantly increased in TNBC samples compared to normal tissues. Further studies indicate that the manipulation of KLF5 expression positively alters TNFAIP2 expression levels. Furthermore, the results of dual luciferase assay, chromatin immunoprecipitation assay (ChIP) and oligo pull-down indicated KLF5 directly bounds to Sp1 sites at the TNFAIP2 gene promoter to regulate promoter activity and gene transcription.Secondly, TNFAIP2 is an oncogene in breast cancer promoting breast cancer cell growth and proliferation, non-adherent soft agar colony formation and tumor growth. KLF5 promotes breast cancer cell growth and proliferation at least in part through inducing TNFAIP2. In addition, both KLF5 and TNFAIP2 can regulate adhesion, migration and invasion of TNBC cells. KLF5 modulates breast cancer cell morphology and actin cytoskeleton, and then promotes cell migration and invasion through TNFAIP2.Furthermore, TNFAIP2 indirectly or directly interacts with Cdc42 and Rac1, thereby increasing the levels of GTP-bound Cdc42 and Rac1. KLF5 and TNFAIP2 activate Cdc42 and Rac1, modulate the actin cytoskeleton and morphology and promote TNBC cell proliferation, migration and invasion. Drugs targeting the expression and activity of Cdc42 or Rac1 block KLF5-TNFAIP2-Rac1/Cdc42 pathway and inhibit TNBC cells proliferation. In summary, the findings suggest the expression of TNFAIP2 is highly correlated with the expression of KLF5 in breast cancers. KLF5 directly binds to the TNFAIP2 gene promoter and activates its transcription. Functionally, KLF5 promotes cancer cell proliferation, migration and invasion in part through TNFAIP2. TNFAIP2 interacts with the two small GTPases Rac1 and Cdc42, thereby increasing their activities of regulating actin cytoskeleton and cell morphology. Both KLF5 and TNFAIP2 promote breast cancer cell proliferation, migration and invasion through Rac1 and Cdc42. Therefore, KLF5 and TNFAIP2 are potentially valuable molecular markers for diagnosis and prognosis, and molecular targets for drug treatment in triple negative breast cancer.
学科领域	细胞生物学
语种	中文
文献类型	学位论文
条目标识符	http://ir.kiz.ac.cn/handle/152453/11982
专题	科研部门_肿瘤生物学（陈策实）
作者单位	中国科学院昆明动物研究所
推荐引用方式 GB/T 7714	贾琳. KLF5通过TNFAIP2调控乳腺癌细胞的增殖、迁移和侵袭[D]. 北京. 中国科学院研究生院,2015.

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