Heat shock proteins in cancer and signaling

癌症和信号转导中的热休克蛋白

• 批准号: 7406668
• 负责人: Michael Y Sherman
• 金额: $ 34.31万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-05-01 至 2009-09-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7406668
• 关键词: 17-(Allylamino)-17-demethoxygeldanamycin; Aftercare; Anchorage-Independent Growth; Antineoplastic Agents; Apoptosis; Apoptotic; Cell Line; Cells; Class; Condition; Cultured Tumor Cells; Development; Down-Regulation; Drug resistance; Fever; Genetic Transcription; Goals; Growth; Heat shock proteins; Heat-Shock Response; Indium; Knock-out; Maintenance; Malignant Neoplasms; Mammary Neoplasms; Mammary gland; Mediating; Molecular; Multiple Myeloma; NF-kappa B; Normal Cell; Oncogenes; Pathway interactions; Pharmaceutical Preparations; Property; Prostate; Proteasome Inhibitor; Protein Overexpression; Proteins; Rate; Recombinants; Reporting; Research; Resistance; Role; Signal Pathway; Signal Transduction; Small Interfering RNA; Structure; Testing; Tissues; Transgenic Mice; Translations; Tumor Cell Line; Tumorigenicity; Velcade; Xenograft Model; analog; base; c-myc Genes; cancer cell; cancer therapy; drug sensitivity; hyperthermia treatment; inhibitor/antagonist; mammary epithelium; multicatalytic endopeptidase complex; neoplastic cell; novel; programs; research study; small molecule; small molecule libraries; transcription factor; tumor; tumor xenograft; tumorigenic

DESCRIPTION (provided by applicant): Heat shock proteins (Hsps) are constitutively expressed in many tumors, suggesting that these proteins provide a selective advantage to cells in tumor development. Expression of recombinant Hsp72 enhances tumorigenicity, while abrogation of Hsp72 from tumor cells (but not normal cells) reduces their tumorigenic properties and sensitizes to certain drugs. The first goal of this proposal is to elucidate the role of the elevated expression of Hsp72 in cancer cells. We hypothesize that Hsp72 allows tumor cells to escape apoptosis induced by activated oncogenes and to survive toxic conditions of tumor microenvironments. This hypothesis will be evaluated with immortalized mammary epithelium cells that over-express c-myc oncogene, and the mechanisms of the Hsp72-mediated suppression of apoptosis will be elucidated. Experiments with transgenic mice that overexpress both c-myc and Hsp72 in mammary tissue will test the significance of these findings for cancer development. Specific depletion of Hsp72 in some tumor cell lines leads to enhanced sensitivity to certain anti-cancer agents, and to reduced growth rate and anchorage-independent growth, which coincide with downregulation of the NF-kappaB signaling pathway. We will test a hypothesis that downregulation of this pathway is responsible for enhanced drug sensitivity and reduced tumorigenic properties of cancer cells upon depletion of Hsp72. The second goal is to establish the role of the heat shock response in cancer cell resistance to proteasome and Hsp90 inhibitors. Hyperthermia, proteasome inhibitors (e.g. Velcade) and Hsp90 inhibitors (e.g. 17-AAG) are three novel anti-cancer treatments, which strongly induce heat shock proteins. We hypothesize that inhibition of the heat shock response could enhance the potency of these treatments. In fact, deletion of the Hsfl transcription factor in MEF cells leads to a block of Hsps induction after hyperthermia, Velcade and 17-AAG, and enhances the sensitivity to these treatments. Hsf1 will be abrogated by siRNA in multiple myeloma, prostate and breast tumor cell lines, and sensitivity of these clones to Velcade and 17-AAG will be tested. With xenograft models, we will establish if downregulation of Hsf1 enhances tumor sensitivity to Velcade and 17-AAG. We have screened 35,000 compounds from several chemical libraries and identified 9 molecules, which potently (in micromolar and sub-micromolar concentrations) inhibit induction of Hsps by heat shock, Velcade and 17-AAG. We will analyze analogs of the two most promising compounds to identify critical elements in their structures and obtain non-toxic potent specific inhibitors of induction of Hsps. These inhibitors will be tested for their ability to enhance the potency of Velcade and 17-AAG in tumor cell cultures. These experiments will test a hypothesis that inhibitors of the heat shock response can enhance the anti-cancer activities of proteasome and Hsp90 inhibitors.

描述（由申请人提供）：热休克蛋白（Hsps）在许多肿瘤中组成型表达，表明这些蛋白质在肿瘤发展中为细胞提供选择性优势。 重组Hsp 72的表达增强了致瘤性，而从肿瘤细胞（但不是正常细胞）中废除Hsp 72降低了它们的致瘤性并对某些药物敏感。 该建议的第一个目标是阐明Hsp 72在癌细胞中表达升高的作用。 我们推测，热休克蛋白72允许肿瘤细胞逃避激活的癌基因诱导的凋亡和生存的肿瘤微环境的毒性条件。 这一假设将与永生化乳腺上皮细胞过表达c-myc癌基因进行评估，Hsp 72介导的抑制细胞凋亡的机制将得到阐明。 用在乳腺组织中过表达c-myc和Hsp 72的转基因小鼠进行的实验将检验这些发现对癌症发展的意义。 某些肿瘤细胞系中Hsp 72的特异性缺失导致对某些抗癌剂的敏感性增强，并导致生长速率降低和锚定非依赖性生长，这与NF-κ B信号传导途径的下调一致。 我们将测试一个假设，即下调这一途径是负责增强药物敏感性和减少肿瘤的性质后，耗尽热休克蛋白72的癌细胞。 第二个目标是确定热休克反应在癌细胞对蛋白酶体和Hsp 90抑制剂的抗性中的作用。 热疗、蛋白酶体抑制剂（如万珂）和Hsp 90抑制剂（如17-AAG）是三种新型的抗癌治疗方法，它们强烈诱导热休克蛋白。 我们推测抑制热休克反应可以增强这些治疗的效力。 事实上，MEF细胞中Hsfl转录因子的缺失导致热疗、万珂和17-AAG后Hsps诱导的阻断，并增强了对这些治疗的敏感性。 在多发性骨髓瘤、前列腺和乳腺肿瘤细胞系中，Hsf 1将被siRNA消除，并将测试这些克隆对万珂和17-AAG的敏感性。 在异种移植模型中，我们将确定Hsf 1的下调是否会增强肿瘤对万珂和17-AAG的敏感性。 我们已经从几个化学文库中筛选了35，000种化合物，并鉴定了9种分子，其有效地（以微摩尔和亚微摩尔浓度）抑制热休克、万珂和17-AAG诱导的Hsps。 我们将分析这两个最有前途的化合物的类似物，以确定其结构中的关键元素，并获得无毒的有效的Hsps诱导特异性抑制剂。 将检测这些抑制剂在肿瘤细胞培养物中增强万珂和17-AAG效力的能力。 这些实验将检验热休克反应抑制剂可以增强蛋白酶体和Hsp 90抑制剂的抗癌活性的假设。