MicroRNAs as Targets for Colon Cancer Chemotherapy

描述（由申请人提供）：结直肠癌是包括美国在内的大多数发达国家的主要死亡原因之一。结肠癌化疗依赖于许多细胞毒性药物、靶向药物及其组合，并且越来越需要开发靶向特定途径的替代药物，以抑制肿瘤生长、进展和转移并诱导细胞凋亡。特异性蛋白（Sps）是在许多肿瘤中过表达的转录因子，并且Sps调节癌细胞和肿瘤生长（p27抑制）、存活（存活素）和血管生成（VEGF、VEGFR 1和VEGFR 2）所需的基因的表达。本实验室的研究现已表明，托芬那酸（TA）和桦木酸（BA）以及一种新的合成三萜酸（酯），即甲基-2-氰基-3，11-二氧代-1，12-二烯-30-酸酯（CDODA-Me）诱导结肠癌细胞中Sp蛋白的G2/M生长停滞和蛋白酶体非依赖性降解。这些作用与化合物诱导的致癌microRNA-27 a（mir-27 a）和其他miR表达的调节直接相关。因此，我们假设TA、BA和CDODA-Me代表了一类独特的靶向miR-27 a和其他miR的抗癌药物。拟议的研究将表征结肠癌中药物-miR相互作用产生的作用和效应机制。目的1将关注TA-/BA-/CDODA-Me-miR-27 a相互作用，并研究miR-27 a依赖的ZBTB 10和Myt-1表达的激活及其随后的下游调控Sp和Sp依赖的基因，结肠癌细胞中的生长抑制，抗血管生成和促凋亡反应。TA、BA和CDODA-Me还降低结肠癌细胞中其他miR的表达，这些miR包括与miR-27 a形成簇的miR-23 a和miR-24-2。目的2研究TA-、BA-和CDODA-Me-miR（23 a ~24-2）的相互作用，并确定它们在介导这些化合物抗癌活性中的作用。目的3将研究TA、BA和CDODA-Me在小鼠异种移植物和结肠癌“Min”模型中的体内抗癌活性，并确定化合物-miR相互作用。此外，已经开发了过表达miR-27 a的小鼠作为探针，用于研究这种致癌miR在结肠癌发生中的作用。这些研究将提供有关TA、BA和CDODA-Me作为一类新型抗癌药物的疗效和作用机制的关键数据，这些药物通过多种途径发挥作用，包括对microRNA及其相关基因转录物的直接作用。

DESCRIPTION (provided by applicant): Colorectal cancer is one of the leading causes of death in most developed countries including the United States. Colon cancer chemotherapy relies on a number of cytotoxic drugs, targeted agents and their combinations, and there is an increasing need to develop alternative drugs targeting specific pathways that inhibit tumor growth, progression and metastasis and induce apoptosis. Specificity proteins (Sps) are transcription factors overexpressed in many tumors, and Sps regulate expression of genes required for cancer cell and tumor growth (p27 suppression), survival (survivin), and angiogenesis (VEGF, VEGFR1 and VEGFR2). Studies in this laboratory have now shown that tolfenamic acid (TA) and betulinic acid (BA) and a novel synthetic triterpenoid acid (ester), namely methyl-2-cyano-3,11-dioxo-18¿-olean-1,12-dien-30-oate (CDODA-Me) induce G2/M growth arrest and proteasome-independent degradation of Sp proteins in colon cancer cells. These effects are directly linked to compound-induced modulation of expression of oncogenic microRNA-27a (mir-27a) and other miRs. Therefore, we hypothesize that TA, BA and CDODA-Me represent a unique class of anticancer agents that target miR-27a and other miRs. The proposed studies will characterize the mechanisms of action and effects resulting from drug-miR interactions in colon cancer. Aim 1 will focus on TA-/BA-/CDODA-Me-miR-27a interactions and investigate the activation of miR-27a-dependent ZBTB10 and Myt-1 expression and their subsequent downstream modulation of Sp and Sp-dependent genes, growth inhibitory, antiangiogenic and proapoptotic responses in colon cancer cells. TA, BA and CDODA-Me also decrease expression of other miRs in colon cancer cells, and these include miR-23a and miR-24-2 which form a cluster with miR-27a. Aim 2 will investigate TA-, BA- and CDODA-Me-miR(23a~24-2) interactions and determine their role in mediating the anticarcinogenic activities of these compounds. Aim 3 will investigate the in vivo anticarcinogenic activity of TA, BA and CDODA-Me in a mouse xenograft and "Min" model for colon cancer and determine the compound-miR interactions. In addition, mice overexpressing miR-27a have been developed as probes for investigating the role of this oncogenic miR in colon carcinogenesis. These studies will provide critical data on the efficacy and mechanisms of action of TA, BA and CDODA-Me as a novel class of anticancer drugs that act through multiple pathways including direct effects on microRNAs and their associated gene transcripts.