Bitter Melon Component and Colon Cancer Prevention

苦瓜成分与预防结肠癌

• 批准号: 8796002
• 负责人: Shrikant Anant
• 金额: $ 54.47万
• 依托单位: UNIVERSITY OF KANSAS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8796002
• 关键词: 1-Phosphatidylinositol 3-Kinase; AKT1 gene; Adverse effects; Affect; Alleles; Architecture; Biological Factors; Biological Markers; Calmodulin; Cancer Etiology; Cells; Clinic; Clinical Research; Collaborations; Colon Carcinoma; Colonic Neoplasms; Colonic Polyps; Colorectal Cancer; Data; Degradation Pathway; Diet; E2F Transcription Factor 1; E2F1 gene; Endothelial Cells; Epithelial Cells; Fibroblasts; Future; Glycogen Synthase Kinase 3; Goals; Growth; Growth Factor; Health; Human; Intestines; JNK-activating protein kinase; Knock-out; Lead; Left; Lung; MAPK8 gene; Malignant Neoplasms; Mediating; Melons; Methods; Modeling; Morbidity - disease rate; Mus; Neoplasm Metastasis; Organ; PDPK1 gene; Pathway interactions; Phosphorylation; Phosphotransferases; Prevention; Preventive; Protein-Serine-Threonine Kinases; Proteins; Proto-Oncogene Proteins c-akt; Relapse; Role; Serine; Signal Transduction; Site; Stem cells; System; Testing; Therapeutic; Threonine; Ubiquitin; United States; adenoma; base; cancer cell; cancer prevention; cancer stem cell; cell growth; cell type; cytokine; fruits and vegetables; in vivo; inhibitor/antagonist; killings; mortality; multicatalytic endopeptidase complex; mutant; novel; overexpression; pre-clinical; preclinical study; prevent; public health relevance; screening; stress-activated protein kinase 1; tumor; tumor growth; tumor microenvironment; tumor xenograft; tumorigenesis; ubiquitin-protein ligase; villin

DESCRIPTION (provided by applicant): Despite the best screening efforts to identify and remove colon polyps, colon cancer remains a leading cause of cancer related morbidity and mortality, both in the US and around the world. Also, current therapeutics while good in removing most cancer cells are not adequate because they leave some cells behind. This is because these cells can reemerge and develop a fresh tumor, which in many cases can manifest in a different organ due to metastasis. The advantage of using natural products that originate from fruits and vegetables over synthetic agents for preventing cancer is that they promote human health without recognizable side effects. In this regard, we have recently shown that bitter melon extracts (BME) inhibit the growth of DCLK1+ cells. We have now discovered that charantin, an active ingredient in the extracts is a potent inhibitor of colon cancer growth. The goal of the current project is to further characterize charantin and generate preclinical data as a dietary agent for the prevention of colon cancer. In preliminary studies, we have determined that charantin inhibits DCLK1 kinase activity and that of a related kinase CAMKIIa but not that of CAMKIIb and CAMKIV. Furthermore, charantin inhibits DCLK1 induced phosphorylation of AKT1/PKB. AKT1 is a serine-threonine protein kinase that is catalytically inactive until it is phosphorylated at two critical sites, Thr308 and Ser473. Various agents such as growth factors, and cytokines can rapidly activate the protein through the actions of phosphatidylinositol 3-kinase (PI3K). Upon activation, AKT1 induces phosphorylation of GSK-3b and also inhibits JNK activation. We have determined that charantin suppresses AKT1 activation and induces JNK. Moreover, JNK induces b-catenin phosphorylation, which in turn is subjected to b-TRCP independent, SIAH1- dependent ubiquitin-proteasome degradation pathway. We have also determined that charantin inhibits the growth of colon cancer cells in a novel culture method termed "Tumor in a Dish" (TiD). In this system, cells are grown in a three dimensional matrix that contains normal lung cells including normal epithelial cells, fibroblasts and endothelial cells. The model creates a near-in vivo tumor microenvironment including cell-cell contact, 3D- architecture, and the influence of different cell types. The observed selective killing of cancer cells in this system suggests that the compounds are highly specific and have good potency. Based on these preliminary results, we propose to further develop charantin as a dietary prevention agent and move it towards the clinic. In aim 1, we propose to determine the role of PI3 kinase in charantin effect on DCLK1-mediated AKT1 activation. In Aim 2, we propose to determine whether charantin affects AKT-mediated ¿-catenin activation. Finally, in Aim 3, we will determine whether charantin induces JNK1 kinase and SIAH1 to induce ¿-catenin degradation. We will determine the effect of the compound on DCLK1 expression, and on Akt phosphorylation, and b-catenin degradation. These studies will also aid in understanding a non-canonical pathway to suppress b-catenin signaling and identify novel biomarkers for the future clinical studies.

描述（由申请人提供）：尽管在识别和切除结肠息肉方面付出了最好的筛查努力，但结肠癌仍然是美国和世界各地癌症相关发病率和死亡率的主要原因。此外，目前的疗法虽然可以有效去除大多数癌细胞，但还不够，因为它们会留下一些细胞。这是因为这些细胞可以重新出现并形成新的肿瘤，在许多情况下，该肿瘤可以由于转移而出现在不同的器官中。与合成药物相比，使用源自水果和蔬菜的天然产品来预防癌症的优势在于，它们可以促进人类健康，且没有可识别的副作用。在这方面，我们最近发现苦瓜提取物 (BME) 抑制 DCLK1+ 细胞的生长。我们现在发现，提取物中的活性成分苦瓜素是结肠癌生长的有效抑制剂。当前项目的目标是进一步表征苦瓜素并生成作为预防结肠癌的饮食剂的临床前数据。在初步研究中，我们确定苦瓜素抑制 DCLK1 激酶活性和相关激酶 CAMKIIa 的活性，但不抑制 CAMKIIb 和 CAMKIV 的活性。此外，苦瓜素还能抑制 DCLK1 诱导的 AKT1/PKB 磷酸化。 AKT1 是一种丝氨酸-苏氨酸蛋白激酶，在两个关键位点 Thr308 和 Ser473 被磷酸化之前，其催化失活。生长因子和细胞因子等多种物质可以通过磷脂酰肌醇 3-激酶 (PI3K) 的作用快速激活蛋白质。激活后，AKT1 会诱导 GSK-3b 磷酸化并抑制 JNK 激活。我们已确定苦瓜素可抑制 AKT1 激活并诱导 JNK。此外，JNK 诱导 b-catenin 磷酸化，而 b-catenin 磷酸化又受到 b-TRCP 独立、SIAH1 依赖性泛素蛋白酶体降解途径的影响。我们还确定苦瓜素在一种称为“培养皿中的肿瘤”(TiD) 的新型培养方法中抑制结肠癌细胞的生长。在该系统中，细胞在包含正常肺细胞（包括正常上皮细胞、成纤维细胞和内皮细胞）的三维基质中生长。该模型创建了近体内肿瘤微环境，包括细胞间接触、3D 结构以及不同细胞类型的影响。在该系统中观察到的选择性杀死癌细胞表明这些化合物具有高度特异性并且具有良好的效力。基于这些初步结果，我们建议进一步开发苦瓜素作为饮食预防剂并将其推向临床。在目标 1 中，我们建议确定 PI3 激酶在苦瓜素对 DCLK1 介导的 AKT1 激活的影响中的作用。在目标 2 中，我们建议确定苦瓜素是否影响 AKT 介导的 ¿-catenin 激活。最后，在目标 3 中，我们将确定苦瓜素是否诱导 JNK1 激酶和 SIAH1 诱导 ¿-catenin 降解。我们将确定该化合物对 DCLK1 表达、Akt 磷酸化和 b-连环蛋白降解的影响。这些研究还将有助于了解抑制 β-连环蛋白信号传导的非典型途径，并为未来的临床研究确定新的生物标志物。