Role of Claudin-2 in Colon Tumorigenesis

Claudin-2 在结肠肿瘤发生中的作用

• 批准号: 9553354
• 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/9553354
• 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; Mucous Membrane; 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; 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; colorectal cancer prevention; colorectal cancer progression; 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）： 尽管临床管理取得了最新进展，但结直肠癌（CRC）仍然是退伍军人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CRC患者，癌症进展仍然是CRC相关死亡的主要原因。因此，对可以预防CRC进展的疗法的需求仍然迫切。 该提案利用了我们和其他小组的关键临床观察结果，即紧密连接（TJ）蛋白claudin-2的表达在CRC中高度上调，促进体内结肠肿瘤发生并保护免受化疗药物诱导的细胞死亡。然而，尽管已证实了claudin-2促进CRC的能力，但claudin-2的潜在机制以及治疗潜力仍未被探索。重要的是，在结肠中表达的claudin中，claudin-2仅在隐窝底部（增殖区）的未分化的结肠细胞中独特地表达，并且在体外和体内促进结肠上皮细胞（CEC）增殖。值得注意的是，claudin-2是Wnt信号传导的转录靶标。此外，组织微环境以EGFR依赖性方式调节结肠claudin-2表达。EGFR-和Wnt-信号传导调节结肠干细胞小生境，因此我们已经发现相对于各自的对照，在过表达密蛋白-2的细胞或小鼠中干细胞标志物Lgr-5、Olf 4和CD-133的表达上调。在CRC中，增殖表型与去分化相关。因此，claudin-2表达随着CRC细胞的分化而降低，并且当过表达时抵抗分化。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CEC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，组成型claudin-2表达导致免疫抑制。值得注意的是，免疫抑制条件有助于促进肿瘤进展。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如何调节结肠肿瘤生长和肿瘤细胞可塑性。在这里，我们将确定：A）密蛋白-2在调节结肠细胞分化、干细胞龛和肿瘤细胞可塑性中的作用; B）密蛋白-2是否促进自噬以促进肿瘤细胞存活和化学抗性;和C）密蛋白-2表达是否调节宿主-肿瘤免疫相互作用以促进肿瘤进展;和Aim-2）以确定EGFR和Wnt信号传导在结肠紧密连接蛋白-2表达和治疗潜力的调节中的作用。在这里，我们将确定：A）EGFR依赖性信号传导、转录机制和与Wnt/β-连环蛋白信号传导的潜在串扰在密蛋白-2表达调节中的作用;和B密蛋白-2作为与EGFR和Wnt信号传导结合的CRC生物标志物的作用。我们的短期目标是更好地了解claudin-2表达失调如何调节结肠癌细胞形成肿瘤和进一步发展的能力。我们的长期目标是开发策略来抑制claudin-2表达，特别适用于结肠癌细胞，从而创造一种可以预防疾病进展的抗CRC药物。我们相信这种治疗干预可以显着提高患有结直肠癌的美国退伍军人的生存率和生活质量。