Molecular and Epigenetic Control of Wnt/b-catenin-mediated oncogenesis by KDM4B

KDM4B 对 Wnt/b-catenin 介导的肿瘤发生的分子和表观遗传控制

• 批准号: 9892322
• 负责人: CUN-YU WANG
• 金额: $ 42.85万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/9892322
• 关键词: APC gene; ASCL2 gene; Alleles; ApcMin/+ mice; Biological Assay; CCND1 gene; CTNNB1 gene; Cause of Death; Cell Proliferation; Cell physiology; Cells; ChIP-seq; Chemicals; Clinical; Colonic Neoplasms; Colorectal; Colorectal Cancer; Cyclin D1; Development; Drug resistance; Enzymes; Epigenetic Process; Exhibits; Feedback; Gene Activation; Gene Silencing; Genes; Genetic; Genetic Transcription; Growth; Human; Impairment; Individual; Intestines; Knock-out; LGR5 gene; Label; Lead; Lysine; Malignant Neoplasms; Mediating; Methylation; Modeling; Modification; Molecular; Molecular Genetics; Mus; Mutation; Oncogenic; Patient-Focused Outcomes; Pharmacology; Phenotype; Play; Property; Reaction; Recurrence; Reporting; Resistance development; Role; Signal Pathway; Signal Transduction; Small Intestines; Stem Cell Factor; TCF Transcription Factor; Therapeutic; Tumor Stem Cells; Weight Gain; adenoma; base; beta catenin; cancer cell; cancer initiation; cancer stem cell; chemotherapy; colorectal cancer progression; demethylation; drug development; histone demethylase; improved; in vivo; knock-down; mouse model; neoplastic cell; new therapeutic target; novel; novel strategies; novel therapeutics; promoter; public health relevance; recruit; self-renewal; small molecular inhibitor; small molecule inhibitor; stem cell model; stem cells; stem-like cell; transcription factor; transcriptome sequencing; treatment strategy; tumor; tumor growth; tumor initiation; tumorigenesis; tumorigenic; villin

Project Summary/Abstract Abnormal Wnt/β-catenin signaling is associated with various types of human cancers, most notably colorectal cancers (CRCs) due to APC and CTNNB1 (β-catenin) mutations. CRCs are the third most common cancer worldwide and the fourth most common cause of death. Wnt/β-catenin signaling exhibits its oncogenic activities by inducing the expression of Wnt target genes such as CCND1 (Cyclin D1) and MYC (c-Myc) through β-catenin/T cell factor (Tcf)-mediated transcription. Although APC and CTNNB1 mutations play a critical role in human CRC initiation and development, emerging evidence suggests that epigenetic modifications act synergistically in human CRC initiation and development. A small subset of cancer stem cells (CSCs) or cancer initiating cells with the ability to self-renew and maintain the tumor has been isolated from human CRCs. We and others have found that β-catenin/Tcf-mediated transcription is hyperactivated in human colorectal CSCs compared to non-CSC tumor cells. In this application, we identified that lysine-specific demethylase 4B (KDM4B) that erases H3K9me3 marks was highly expressed in human CRCs. The knockdown or pharmacological inhibition of KDM4B in human CRC cells significantly inhibited the expression of Wnt target genes. To explore the functional roles of KDM4B in vivo, we generated Kdm4bflox/flox (Kdm4bf/f) mice that carry conditional Kdm4b alleles. Although the deletion of Kdm4b in mice causes intestinal abnormalities and reduced crypt stem cells, unlike the deletion of β-catenin, we found that mice can tolerate KDM4B deficiency, indicating that targeting KDM4B might provide a safe therapeutic window for the treatment of human CRCs. Consistently, we found that the intestinal deletion of Kdm4b completely inhibited intestinal tumorigenesis in ApcMin/+ mice which develop multiple adenomas in the small intestine due to increased β-catenin/Tcf-mediated transcription. Additionally, we found that KDM4B interacts with the intestinal stem cell transcription factor ASCL2 which serve as a positive feedback to enhance β-catenin/Tcf-mediated transcription. Based on these exciting discoveries, we hypothesize that KDM4B might epigenetically control Wnt/β-catenin-mediated oncogenesis and is required for the tumorigenic potentials of human colorectal CSCs. Using molecular, cellular, genetic and epigenetic approaches, we will determine: 1) Whether the knockout or pharmacological inhibition of KDM4B inhibits CRC tumorigenesis in vivo; 2) Whether KDM4B epigenetically controls tumorigenic potentials and self-renewal of CSCs in human CRCs; 3) How KDM4B epigenetically controls Wnt/β-catenin-mediated transcription and tumorigenesis by erasing H3K9me3. Since histone demethylases are enzymes which can be readily targeted by small molecules inhibitors, novel findings from our studies may lead to develop novel strategies for the treatment of human CRCs and other cancers.

项目摘要/摘要 Wnt/β-catenin信号传导异常与各种类型的人类癌有关，最著名的是 由于APC和CTNNB1（β-catenin）突变引起的结直肠癌（CRC）。 CRC是第三大常见的 全球癌症和第四大死亡原因。 Wnt/β-catenin信号传导表现出其致癌性 通过诱导Wnt靶基因（例如CCND1（Cyclin D1）和Myc（C-Myc））的表达的活性通过 β-catenin/T细胞因子（TCF）介导的转录。尽管APC和CTNNB1突变在 人类CRC倡议和发展，新兴证据表明，表观遗传修饰法 在人类CRC的启动和发展方面协同作用。一小部分癌症干细胞（CSC）或癌症 具有自我更新和维持肿瘤的能力的启动细胞已从人CRC中分离出来。我们和 其他人发现β-catenin/TCF介导的转录在人结直肠CSC中过度培训 与非CSC肿瘤细胞相比。在此应用中，我们确定了赖氨酸特异性脱甲基酶4B（KDM4B） 擦除H3K9ME3标记在人CRC中高度表达。敲低或药理 在人CRC细胞中抑制KDM4B会显着抑制Wnt靶基因的表达。探索 KDM4B在体内的功能作用，我们生成了携带有条件KDM4B的KDM4BFLOX/FLOX（KDM4BF/F）小鼠 等 与β-catenin的缺失不同，我们发现小鼠可以忍受KDM4B缺乏症，表明靶向 KDM4B可能会为治疗人CRC提供安全的治疗窗口。一贯，我们发现 KDM4B的肠道缺失完全抑制了apcmin/+小鼠的肠道肿瘤发生 由于β-catenin/TCF介导的转录增加，小肠中的多个腺瘤。另外，我们 发现KDM4B与肠道干细胞转录因子ASCL2相互作用，该因子作为正 反馈以增强β-catenin/TCF介导的转录。基于这些令人兴奋的发现，我们假设 KDM4B可能会表观遗传控制Wnt/β-catenin介导的肿瘤发生，并且是必需的 人结直肠CSC的致瘤潜力。使用分子，细胞，遗传和表观遗传学方法， 我们将确定：1）KDM4B的基因敲除或药理抑制是否抑制CRC肿瘤发生 体内; 2）KDM4B是否表观遗传控制人类CSC的致瘤潜力和自我更新 CRC; 3）KDM4B如何通过表观遗传控制Wnt/β-catenin介导的转录和肿瘤发生 擦除H3K9me3。由于组蛋白脱甲基酶是酶，可以容易被小分子靶向 抑制剂，我们研究的新发现可能导致制定治疗人CRC的新策略 和其他癌症。