Role of Claudin-2 in Colon Tumorigenesis

Claudin-2 在结肠肿瘤发生中的作用

• 批准号: 9252978
• 负责人: Amar B Singh
• 金额: --
• 依托单位: OMAHA VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2020-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9252978
• 关键词: Affect; Antineoplastic Agents; Asses; Autophagocytosis; Biological Assay; Caco-2 Cells; Cancer Etiology; Cartoons; Cell Death; Cell Survival; Cells; Cellular Stress; Cessation of life; Clinical; Clinical Management; Colon; Colon Carcinoma; Colonic Neoplasms; Colorectal Cancer; Data; Disease; Disease Progression; Epidermal Growth Factor Receptor; Epithelial; Epithelial Cell Proliferation; Epithelial Cells; Event; Family member; Financial compensation; Fostering; Future; Genetic Transcription; Goals; Growth; Immune; Immunologic Surveillance; Immunosuppression; In Vitro; Light; Messenger RNA; Military Personnel; Molecular; Mus; Mutation; Nature; Oncogenic; Outcome; Patients; Pharmaceutical Preparations; Phenotype; Population; Predisposition; Proteins; Quality of life; Regulation; Research; Resistance; Role; Signal Pathway; Signal Transduction; Stem cells; Stress; Testing; Therapeutic; Therapeutic Intervention; Tight Junctions; Tissues; Transgenic Mice; Tumorigenicity; Undifferentiated; Up-Regulation; Veterans; WNT Signaling Pathway; beta catenin; cancer biomarkers; cancer cell; cancer stem cell; cell growth; colon cancer patients; colon carcinogenesis; colon tumorigenesis; immunoregulation; in vivo; individualized medicine; mortality; neoplastic cell; novel; novel therapeutics; offspring; outcome forecast; outcome prediction; overexpression; prevent; public health relevance; selective expression; stem cell niche; tumor; tumor growth; tumor progression; tumorigenic; villin

 DESCRIPTION (provided by applicant): Despite the recent advances in the clinical management, colorectal cancer (CRC) remains 2nd leading cause of the cancer-related deaths in Veteran armed forces personnel. Each year Veterans affairs manage and treat ~175,000 CRC-patients and cancer progression remains the principal cause of CRC-associated death. Thus, need for therapies that can prevent CRC progression remains urgent. This proposal exploits a key clinical observation by us and other groups that expression of claudin-2, a tight junction (TJ) protein, is highly upregulated in CRC, promotes colon tumorigenesis in vivo and protects from cell death induced by chemotherapeutic drugs. However, despite the proven ability of claudin-2 to promote CRC, underlying mechanisms as well as therapeutic potential of claudin-2 remain unexplored. Importantly, among claudins expressed in colon, claudin-2 is uniquely expressed only among the undifferentiated colonocytes at crypt bottom, the proliferative zone, and promotes colonic epithelial cell (CEC) proliferation, in vitro and in vivo. Notably, claudin-2 is a transcriptional target of Wnt-signaling. Further, tissue microenvironment regulates colonic claudin-2 expression in EGFR-dependent manner. The EGFR- and Wnt-signaling regulate colonic stem cell niche and accordingly we have found upregulated expression of Lgr-5, Olf4 and CD-133, stem cell markers in cells or mice overexpressing claudin-2 versus respective controls. In CRC, a proliferative phenotype associates with dedifferentiation. In accordance, claudin-2 expression decreases with the differentiation in CRC-cells and resists differentiation when overexpressed. In addition, our preliminary studies suggest that claudin-2 may help protect CECs from stress-induced death by regulating autophagy. Our additional data using Villin-claudin-2 transgenic mice suggest that constitutive claudin-2 expression renders immune-suppression. Notably, immune suppressive conditions help promote tumor progression. Taken together, we hypothesize that claudin-2 expression promotes colon tumorigenesis by facilitating stem cell expansion and plasticity, resistance to cell death and modulation of the host-tumor immune interaction. To test our hypothesis, we propose following specific aims: Aim-1) to determine how claudin-2 regulates colon tumor growth and tumor cell plasticity. Here, we will determine: A) the role of claudin-2 in the regulation of colonocyte differentiation, stem cell niche and tumor cell plasticity; B) whether claudin-2 promotes autophagy to promote tumor cell survival and chemoresistance; and C) whether claudin-2 expression modulates host-tumor immune interaction to promote tumor progression; and Aim-2) to determine the role of EGFR- and Wnt-signaling in the regulation of colonic claudin-2 expression and therapeutic potential. Here, we will determine: A) the role of EGFR-dependent signaling, transcriptional mechanism/s and potential cross-talk with Wnt/β-catenin signaling in the regulation of claudin-2 expression; and B role of claudin-2 as a CRC-biomarker in conjunction with EGFR and Wnt-signaling. Our short term goal is to better understand how dysregulation of claudin-2 expression modulates the ability of colon cancer cells to form tumor and further progression. Our long term goal is to develop strategies to inhibit claudin-2 expression applicable specifically to the colon cancer cell and thus to create an anti-CRC drug that can prevent disease progression. We believe such therapeutic interventions can significantly increase survival and quality of life US Veterans who are suffering from colorectal cancer.

 描述(由申请人提供)： 尽管最近在临床治疗方面取得了进展，但结直肠癌(CRC)仍然是老兵癌症相关死亡的第二大原因。退伍军人事务部每年管理和治疗约175,000名结直肠癌患者，癌症进展仍然是结直肠癌相关死亡的主要原因。因此，对能够防止CRC进展的治疗方法的需求仍然迫切。这一建议利用了我们和其他团队的一个关键临床观察结果，即紧密连接(TJ)蛋白claudin-2在结直肠癌中表达高度上调，促进体内结肠肿瘤的发生，并保护细胞免受化疗药物诱导的细胞死亡。然而，尽管claudin-2已被证实具有促进CRC的能力，其潜在的机制以及治疗潜力仍未被探索。重要的是，在结肠表达的Claudin中，Claudin-2仅在隐窝底部、增殖区的未分化结肠细胞中唯一表达，并在体外和体内促进结肠上皮细胞(CEC)的增殖。值得注意的是，claudin-2是Wnt信号的转录靶点。此外，组织微环境以EGFR依赖的方式调节结肠Claudin-2的表达。EGFR和Wnt信号调节结肠干细胞的生态位，因此我们发现LGR-5、Olf4和CD-133的表达上调，与各自的对照相比，干细胞标记物Claudin-2在细胞或小鼠中过度表达。在结直肠癌中，增殖性表型与去分化相关。相应地，Claudin-2在CRC细胞中的表达随着分化程度的降低而降低，当过度表达时则抵抗分化。此外，我们的初步研究表明，Claudin-2可能通过调节自噬来帮助保护CECs免受应激诱导的死亡。我们使用Villin-claudin-2转基因小鼠的额外数据表明，结构性claudin-2的表达导致了免疫抑制。值得注意的是，免疫抑制条件有助于促进肿瘤的进展。综上所述，我们假设Claudin-2的表达通过促进干细胞的扩增和可塑性、抵抗细胞死亡和调节宿主-肿瘤免疫相互作用来促进结肠肿瘤的发生。为了验证我们的假设，我们提出了以下具体目标：目的1)确定claudin-2如何调控结肠癌生长和肿瘤细胞可塑性。在这里，我们将确定：A)Claudin-2在调节结肠细胞分化、干细胞巢和肿瘤细胞可塑性中的作用；B)Claudin-2是否促进自噬以促进肿瘤细胞存活和化疗耐药；以及C)Claudin-2表达是否调节宿主-肿瘤免疫相互作用以促进肿瘤进展；以及目的-2)确定EGFR-和Wnt-信号在调节结肠Claudin-2表达和治疗潜力中的作用。在这里，我们将确定：A)依赖于表皮生长因子受体的信号、转录机制/S以及与WNT/β-连环蛋白信号的潜在交互作用在调节Claudin-2表达中的作用；以及B，Claudin-2作为结直肠癌标志物与表皮生长因子受体和Wnt-信号一起发挥的作用。我们的短期目标是更好地了解claudin-2表达异常如何调节结肠癌细胞形成肿瘤和进一步进展的能力。我们的长期目标是开发策略，抑制专用于结肠癌细胞的claudin-2表达，从而创造出一种可以防止疾病进展的抗结直肠癌药物。我们相信，这样的治疗干预可以显着提高患有结直肠癌的美国退伍军人的存活率和生活质量。