Protein Arginine Methylation in Chemotherapy Resistance

项目总结 化疗仍然是乳腺癌治疗的一个重要组成部分，给予化疗以减少 转移复发的风险。尽管对此反应(敏感)或缺乏反应(抵抗力) 化疗与预后有关，目前还没有经过验证的商业检测方法。 它专门预测对化疗的反应。癌症治疗的个性化方法有 需要选择对肿瘤最敏感的药物或药物组合，并避免毒性 指肿瘤具有或变得具有抗药性的药物。这样的生物标记物将帮助肿瘤学家每天 对多种化疗敏感的高龄乳房三阴患者的临床处理 主要治疗选择是化疗的癌症患者。 辅活化子相关精氨酸甲基转移酶1(CARM1)是一种蛋白质精氨酸(R)甲基转移酶 它可以甲基化组蛋白H3和各种非组蛋白底物。我们最近确定了一名调解人 RNA聚合酶II转录亚基12(MED12)作为CARM1的新底物。建议数 该项目将确定MED12甲基化是否是乳腺癌化疗敏感性的预测因子。 我们已经将MED12的甲基化位点定位到R1862和R1912。巧合的是，R1862上的突变 在肺癌和宫颈癌中已有报道，在一例黑色素瘤中发现了R1912基因突变 对BRAF抑制剂产生耐药性的患者。我们发现MED12野生型的过度表达，但 而不是MED12R1862K、R1912K突变体增加了HEK293细胞对5-FU和蒽环类药物的敏感性。 有趣的是，MED12甲基化依赖机制不同于转化生长因子-β受体信号的激活 据报道，在肺癌和结肠癌中，MED12基因被完全敲除。此外，我们已经确定了目标 受甲基化的MED12调控，这可能决定化疗敏感性。我们假设甲基化可能是 CARM1表达的MED12代表了化疗敏感性的重要机制。建议数 研究将直接解决(1)MED12甲基化是否预测乳腺癌细胞对 细胞培养和异种移植瘤模型中常用的化疗方法；(2)明确 甲基化-MED12控制的化疗敏感性；以及(3)检测MED12甲基化的临床相关性 在化疗耐药性方面使用了大量的临床样本。我们的目标是描绘出甲基化 化疗耐药的依赖机制和发现治疗干预的新靶点。

PROJECT SUMMARY Chemotherapy continues to be an important component of therapy for breast cancer, given to reduce the risk of metastatic recurrence. Although response (sensitivity) or lack of response (resistance) to chemotherapy is associated with prognosis, there is currently no validated commercial assay available which specifically predicts response to chemotherapy. Personalized approaches to cancer therapy are needed to select a drug or combination of drugs to which a tumor is most sensitive, and to avoid the toxicity of drugs to which the tumor is or becomes resistant. Such biomarker will assist oncologists in the daily clinical management of aging patients who are fragile to multiple chemotherapies and triple negative breast cancer patients whose major treatment option is chemotherapy. Coactivator associated arginine methyltransferase 1 (CARM1) is a protein arginine (R) methyltransferase which can methylate histone H3 and a variety of non-histone substrates. We recently identified a mediator of RNA polymerase II transcription subunit 12 (MED12) as a novel substrate for CARM1. The proposed project will determine whether methylation of MED12 is a predictor for chemo-sensitivity in breast cancer. We have mapped the methylation sites of MED12 to R1862 and R1912. Coincidently, mutations on R1862 had been reported in lung and cervical cancers, and mutations on R1912 had been found in a melanoma patient who developed resistance to BRAF inhibitor. We found that overexpression of MED12 wild-type, but not MED12R1862K,R1912K mutant, increased sensitivity of HEK293 cells to 5-FU and anthracyclines. Interestingly, the MED12 methylation dependent mechanism is distinct from activation of TGF-βR signaling as reported for complete knockout of MED12 in lung and colon cancers. Further, we have identified targets regulated by methylated MED12 that may determine chemo-sensitivity. We hypothesize that methylation of MED12 by CARM1 represents an important mechanism conferring chemosensitivity. The proposed research will directly address (1) whether MED12 methylation predicts sensitivity of breast cancer cells to commonly used chemotherapies in cell culture and xenograft tumor models; (2) define the mechanism of methylated-MED12 controlled chemosensitivity; and (3) test the clinical relevance of the MED12 methylation in chemo- resistance using large cohorts of clinical specimens. The goal is to delineate the methylation dependent mechanism for chemotherapy resistance and uncover new targets for therapeutic intervention.