EFFECT OF BITTER MELON LEAF EXTRACT ON MDR1 GENE EXPRESSION AND FUNCTION OF P-GP

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 结肠癌是第三常见的癌症，占所有癌症死亡的9%，并且是众所周知的化疗耐药。 对治疗反应差和/或患者死亡的原因之一是多药耐药（MDR）现象。 肿瘤多药耐药的机制之一是多药耐药基因mdr 1表达上调，该基因编码一种外排泵，称为磷酸化糖蛋白（P-gp）。 P-gp蛋白充当外排泵并泵出化疗剂，降低药物的细胞内有效剂量并需要施用甚至更高剂量的药物。 P-gp在许多人类癌症中的存在是一个负面的预后因素，并且在肾癌和结肠癌中观察到最高水平的表达。 目前用于克服MDR的方法受到有害副作用和过高毒性的困扰而不能用于患者。 对P-gp抑制剂的研究已经扩展到以植物为基础的天然健康产品。 苦瓜叶提取物对耐药人宫颈癌P-gp活性有抑制作用。 本研究的主要目的是研究苦瓜叶提取物对多药耐药基因1的基因表达，P-gp蛋白功能，潜在的作用，叶提取物作为外排泵抑制剂和叶提取物的能力，以加强已知的化疗药物对多药耐药大肠癌细胞的作用。 将使用的两个品种的苦瓜是台湾白色（苦瓜变种。charantia）和优良育种系CBM-12（苦瓜变种）进行了比较研究。muricata），其果实性状较差，但植物化学物质含量高。 将叶提取物用于结肠癌细胞系，并使用PCR、RT-PCR和染色方法来确定它们对mdrl 1基因表达和P-p蛋白功能的影响。 将对实验产生的数据进行分析，并在两个品种之间进行比较。 拟议项目的长期目标是分离和表征叶提取物中的活性成分，检查纯化产物在影响P-gp功能中的作用，确定不同比例的叶/根/果实对外排泵抑制的影响和体内研究。 这项研究产生的初步数据将有助于验证苦瓜的有益作用，并申请NIH或美国农业部的赠款。 该项目将在癌症治疗和植物医学领域产生更广泛的影响。 我们正在比较受欢迎的栽培品种台湾白色和苦瓜的先进育种系CBM 12品种，培育具有更好药用特性的改良品种将促进小型工业的发展，从而创造就业机会，加强地方经济。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Colon cancer is the third most common cancer, accounts for 9% of all cancer deaths and is notoriously chemoresistant. One of the reasons for poor response to treatment and/or patient death is the phenomenon of multiple drug resistance (MDR). One of the mechanisms of multiple drug resistance in tumors is upregulation of mdr1 gene which encodes an efflux pump known as Phospho-glycoprotein (P-gp). P-gp protein acts as an efflux pump and pump out chemotherapeutic agents, lowering the intracellular effective dose of the drug and requiring administration of even higher doses of drugs. Presence of P-gp in many human cancers is a negative prognostic factor and highest levels f expression seen in renal and colon cancers. The current methods employed to overcome MDR are plagued by detrimental side effects and too high toxicity to be used in patients. The search for P-gp inhibitors has expanded into flora-based natural health products. The leaf extract from bitter melon (Momordica charantia) was found to cause inhibition of P-gp activity in the multidrug-resistant human cervical cancer. The main objectives of this study are to examine the effect of bitter melon leaf extracts on mdr1 gene expression, P-gp protein function, potential role of the leaf extract as an efflux pump inhibitor and the ability of the leaf extract to potentiate the action of known chemotherapeutic drugs against multiple drug resistant colorectal cancer cells. The two varieties of bitter melons that will be used are Taiwan White (Momordica charantia var. charantia) which exhibits superior fruit traits and low content of phytochemicals and an advanced breeding line CBM-12 (Momordica charantia var. muricata) which has inferior fruit traits but a high content of phytochemicals. The leaf extracts will be used on colon cancer cell lines and their effect on mdrl1 gene expression and function of P-p protein will be determined using PCR, RT-PCR and staining methods. The data generated from the experiments will be analyzed and compared between the two varieties. The long-term goals of the proposed project are to isolate and characterize the active component/s in the leaf extract, examine the role of purified product/s in effecting P-gp function, determine the effect of different ratios of leaf/root/fruit on efflux pump inhibition and in vivo studies. The preliminary data generated from this research will help validate the beneficial role of bitter melon and apply for NIH or USDA grants. This project will have a broader impact in helping advance knowledge in the field of cancer therapy and phytomedicine. As we are comparing popular cultivar Taiwan White and an advancing breeding line CBM12 varieties of bitter melon, cultivation of improved varieties with better medicinal properties will foster the growth of small-scale industries leading to generation of employment and strengthening of local economies.