Mechanism of chemoresistance mediated by TGF-beta

TGF-β介导的化疗耐药机制

• 批准号: 8639967
• 负责人: Shizhen Emily Wang
• 金额: $ 33.81万
• 依托单位: BECKMAN RESEARCH INSTITUTE/CITY OF HOPE
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8639967
• 关键词: ATM Signaling Pathway; Animals; Apoptosis; Binding; Biological Assay; Breast Cancer Cell; Cancer Patient; Cell Cycle; Cells; Clinical; Complex; DNA; DNA Binding; DNA Damage; Development; Disease Progression; Dissection; Down-Regulation; Doxycycline; Drug Controls; Drug resistance; Exhibits; Future; Genes; Genetic Transcription; Goals; Growth Factor Receptors; Human; Intervention; Link; MADH2 gene; MADH4 gene; MSH2 gene; Malignant Neoplasms; Mediating; Mediator of activation protein; MicroRNAs; Modeling; Molecular; Molecular Profiling; Molecular and Cellular Biology; Monitor; Mutate; Normal Cell; Outcome; Pathway interactions; Patients; Pharmaceutical Preparations; Phenotype; Poly(ADP-ribose) Polymerases; Process; RNA; RNA Binding; Regulation; Reporter; Reporting; Resistance; Role; Signal Transduction; Staging; Testing; Therapeutic; Transducers; Transforming Growth Factor beta; Transforming Growth Factors; Transplantation; Treatment Efficacy; Tumor Suppressor Proteins; cancer cell; cancer therapy; chemotherapy; chromatin immunoprecipitation; cofactor; cytokine; drug efficacy; experience; in vitro Assay; in vivo; inhibitor/antagonist; innovation; insight; knock-down; malignant breast neoplasm; neoplastic cell; new therapeutic target; novel; novel strategies; novel therapeutics; outcome forecast; overexpression; response; sensor; transcription factor; triple-negative invasive breast carcinoma; tumor; tumor growth; tumor xenograft; vector

DESCRIPTION (provided by applicant): Many chemotherapy drugs act against cancer cells by causing damage to the DNA. Resistance to chemotherapy is a major clinical obstacle in cancer treatment. The mechanisms of chemoresistance in cancer patients are not fully understood, leading to urgent needs for determining factors that control drug response and developing novel therapies to enhance the treatment efficacy. Signaling from transforming growth factor (TGF) ¿, a tumor suppressor in normal cells, is hijacked in cancer to promote disease progression. In breast cancer, TGF- ¿ is linked to poor clinical outcomes and chemoresistance through mechanisms that remain largely unknown. Our previous studies indicate that in breast cancer cells, TGF- ¿ induces microRNAs (miR-21 and miR-181) that target the DNA damage sensors ATM and MSH2, and may therefore regulate cancer response to genotoxic chemotherapy. The goals of this study are to dissect the molecular mechanism of TGF-2-mediated chemoresistance, and to explore potential therapies to enhance drug efficacy. In Aim 1, TGF- ¿ action on cell response to various DNA-damaging treatments and to inhibition of poly(ADP-ribose) polymerase (PARP) will be determined in breast cancer cells with different p53 status using established molecular and cellular biology assays. The role of the TGF- ¿ -regulated miRNAs and the ATM/MSH2 pathways will be determined using gene knockdown and overexpression strategies. In Aim 2, the hypothesis that enhanced SMAD2/3 binding to their RNA targets mediates TGF- ¿ 's functional shift in cancer cells towards inducing miRNA regulation and chemoresistance will be examined. Breast cancer cells expressing various levels of the SMAD2/3 cofactors (i.e., SMAD4, Drosha and p68) will be examined for their dynamic regulation of SMAD2/3 function and TGF-2 effect. In Aim 3, the effect of TGF- ¿ on chemotherapy response and the mechanism identified in the first two aims will be evaluated in animal tumor models. Novel strategies to therapeutically suppress this TGF- ¿ function and enhance the treatment efficacy will be explored. This study will enable better understandings of drug resistance and of TGF- ¿ signaling as both a marker and a target in cancer treatment. Although the mechanism identified herein may have a general application to understanding cancer and defining treatments, our study has added significance for clinically aggressive, hard-to-treat basal- like (mainly triple-negative) breast cancer that often experience active TGF- ¿ signaling. This study will provide novel insight into the functional switch of TGF- ¿ in cancer via SMAD2/3-mediated miRNA processing. Understanding TGF-2-mediated chemoresistance may reveal novel therapeutic targets and strategies that will enhance the chemotherapy efficacy for cancers that lack targets for systemic treatments. Our long-term objectives are to validate this mechanism in primary cancers and establish standard approaches to identify patients suitable for therapies targeting TGF- ¿ 's drug resistant effect, and to understand the global effect of TGF- ¿ -mediated miRNA dysregulation in human cancer.

描述（由申请人提供）：许多化疗药物通过对DNA造成损伤来对抗癌细胞。化疗耐药是癌症治疗的主要临床障碍。癌症患者的化疗耐药机制尚不完全清楚，迫切需要确定控制药物反应的因素并开发新的治疗方法以提高治疗效果。正常细胞中的肿瘤抑制因子转化生长因子（TGF）发出的信号在癌症中被劫持以促进疾病进展。在乳腺癌中，TGF-¿与不良的临床结果和化疗耐药有关，其机制在很大程度上仍然未知。我们之前的研究表明，在乳腺癌细胞中，TGF-¿诱导靶向DNA损伤传感器ATM和MSH2的microrna (miR-21和miR-181)，因此可能调节癌症对遗传毒性化疗的反应。本研究的目的是剖析tgf -2介导的化疗耐药的分子机制，并探索提高药物疗效的潜在治疗方法。在Aim 1中，TGF-¿对细胞对各种dna损伤治疗的反应和对聚（adp -核糖）聚合酶（PARP）抑制的作用将在具有不同p53状态的乳腺癌细胞中使用已建立的分子和细胞生物学分析来确定。TGF-调控的mirna和ATM/MSH2通路的作用将通过基因敲低和过表达策略来确定。在Aim 2中，我们将检验SMAD2/3与其RNA靶点结合增强介导TGF-¿在癌细胞中向诱导miRNA调节和化疗耐药的功能转变的假设。我们将检测表达不同水平SMAD2/3辅助因子（即SMAD4、Drosha和p68）的乳腺癌细胞对SMAD2/3功能和TGF-2效应的动态调节。在Aim 3中，我们将在动物肿瘤模型中评估TGF-¿对化疗反应的影响以及前两个目标确定的机制。我们将探索新的治疗策略来抑制这种TGF-¿功能并提高治疗效果。这项研究将有助于更好地理解耐药性和TGF-¿信号作为癌症治疗的标志物和靶标。虽然本文确定的机制可能在理解癌症和确定治疗方法方面具有普遍应用价值，但我们的研究对临床侵袭性、难以治疗的基底样（主要是三阴性）乳腺癌具有重要意义，这些乳腺癌通常经历活跃的TGF-¿信号。本研究将通过smad2 /3介导的miRNA加工为TGF-¿在癌症中的功能开关提供新的见解。了解tgf -2介导的化疗耐药可能会揭示新的治疗靶点和策略，从而提高缺乏全身治疗靶点的癌症的化疗疗效。我们的长期目标是在原发性癌症中验证这一机制，建立标准方法，以确定适合TGF-¿耐药治疗的患者，并了解TGF-¿介导的miRNA失调在人类癌症中的全局效应。