Targeting Notch, PI3K-AKT and other novel pathways in breast cancer stem cells

靶向乳腺癌干细胞中的 Notch、PI3K-AKT 和其他新通路

• 批准号: 7691767
• 负责人: JENNY C-N CHANG
• 金额: $ 47.85万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-30 至 2013-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7691767
• 关键词: Apoptotic; Biological; Biological Assay; Biological Markers; Biopsy; Biopsy Specimen; Cancer Patient; Cell model; Cells; Characteristics; Clinical; Clinical Research; Clinical Trials; Clinical Trials Design; Colony-Forming Units Assay; Correlative Study; Critical Pathways; Data; Development; Disease; Dose; Drug Kinetics; Epithelial Cells; Flow Cytometry; Future; Genes; Genetic; Human; Human Genome; Immunocompromised Host; In Vitro; Integrins; Laboratories; Libraries; Malignant Neoplasms; Measures; Molecular Target; Neoadjuvant Therapy; Neoplasm Metastasis; Outcome; Pathologic; Pathway interactions; Patients; Population; Pre-Clinical Model; Property; Proto-Oncogene Proteins c-akt; Refractory; Refractory Disease; Relapse; Research Design; Residual Cancers; Residual Tumors; Resistance; Rest; Role; SCID Beige Mouse; Sampling; Series; Signal Pathway; Signal Transduction; Small Inducible Cytokine A3; Stem cells; Subfamily lentivirinae; Systemic Therapy; Testing; Time; Toxicology; Translating; Transplantation; Tumorigenicity; Woman; Xenograft Model; Xenograft procedure; base; cancer cell; cancer stem cell; cancer therapy; chemotherapy; conventional therapy; daughter cell; design; docetaxel; functional genomics; high throughput screening; improved; inhibitor/antagonist; malignant breast neoplasm; notch protein; novel; pre-clinical; preclinical study; prevent; prominin; response; self-renewal; small hairpin RNA; small molecule; therapy resistant; tumor; tumor growth; tumor initiation; tumor xenograft; tumorigenic

DESCRIPTION (provided by applicant): Many patients relapse over time despite initial response to systemic therapy. One explanation is that a rare sub-population of cancer stem cells with tumorigenic potential is intrinsically resistant to therapy. Consistent with this, we have shown for the first time clinically in human breast cancer patients that residual tumors after chemotherapy are 1) enriched for the tumorigenic CD44+/CD24-/low population, 2) show enhanced mammosphere-forming efficiency (MSFE), and 3) display an increase in outgrowths in xenograft transplants in immunocompromised SCID/Beige mice, thus suggesting their increased tumorigenicity. Our recent data from paired human breast cancer samples indicates that standard therapy eliminates dividing daughter cells, so that samples obtained after therapy are enriched for CD44+/CD24-/low putative "breast cancer stem cells" that have the ability to self-renew in mammosphere cultures, and to give rise to tumors upon xenograft transplantation. We have identified a cancer stem cell signature of CD44+/CD24-/low mammosphere-forming cells derived from human breast cancer biopsies. The top canonical pathways identified include Notch and PI3-AKT, and other signaling pathways. We now propose a series of preclinical and clinical studies to directly test the hypothesis that breast cancer stem cells can be specifically targeted by inhibitors of the Notch, PI3-AKT and other pathways. A unique component of our studies is the availability of human biopsy samples obtained before and after targeted therapy in breast cancer patients with residual disease after preoperative (neoadjuvant) therapy. Specific Aims and Study Design 1. To determine whether suppression of identified self-renewal and treatment resistance pathways can improve existing cancer therapies in preclinical models. Beginning with Notch and PI3-AKT inhibitors, we will determine if these will improve efficacy of conventional therapy, using MSFE and human breast cancer xenograft models. Next, we will target the top ~300 genes differentially expressed in our stem cell signature by ordered lentivirus-based shRNA libraries designed to allow genetic "knockdown" of every gene in the human genome, as well as the development of high-throughput functional genomic assays of stem cell self-renewal. 2. To conduct novel clinical trials to determine whether suppressing stem cell self-renewal and treatment resistance pathways can improve existing cancer therapies in breast cancer patients. Clinical trials with novel inhibitors of stem cell self-renewal (Notch and PI3) have been planned. We propose to include patients with advanced breast cancers refractory to conventional therapy, as these women have a poor expected clinical outcome, and who are most likely to benefit from therapies targeting self-renewal pathways. 3. To perform correlative studies using breast cancer biopsy specimens from these clinical trials. Correlative studies using human cancer biopsies from these trials will be conducted, e.g. a decrease in stem cell markers and tumorigenic potential, as well as downstream effects of inhibition of the relevant pathways.

描述（由申请人提供）：尽管对全身治疗有初步反应，但许多患者随着时间的推移会复发。一种解释是，具有致瘤潜力的罕见癌症干细胞亚群本质上对治疗具有抵抗力。与此相一致的是，我们首次在人类乳腺癌患者临床上证明，化疗后残留肿瘤1）富含致瘤性CD44+/CD24-/低群体，2）显示出增强的乳腺球形成效率（MSFE），并且3) 在免疫功能低下的 SCID/Beige 小鼠中显示异种移植物的生长增加，从而表明它们的致瘤性增加。我们最近从配对的人类乳腺癌样本中获得的数据表明，标准疗法消除了分裂的子细胞，因此治疗后获得的样本中富含 CD44+/CD24-/low 假定的“乳腺癌干细胞”，这些细胞具有在乳腺球中自我更新的能力培养物，并在异种移植时产生肿瘤。我们已经鉴定出源自人类乳腺癌活检的 CD44+/CD24-/低乳腺球形成细胞的癌症干细胞特征。已确定的最重要的经典通路包括 Notch 和 PI3-AKT 以及其他信号通路。我们现在提出一系列临床前和临床研究来直接检验这样的假设：Notch、PI3-AKT 和其他途径的抑制剂可以特异性靶向乳腺癌干细胞。我们研究的一个独特组成部分是在术前（新辅助）治疗后有残留疾病的乳腺癌患者的靶向治疗前后获得的人体活检样本。具体目标和研究设计 1. 确定抑制已识别的自我更新和治疗抵抗途径是否可以改善临床前模型中现有的癌症疗法。从 Notch 和 PI3-AKT 抑制剂开始，我们将使用 MSFE 和人类乳腺癌异种移植模型来确定这些抑制剂是否会提高常规疗法的疗效。接下来，我们将通过基于慢病毒的有序 shRNA 文库来靶向干细胞特征中差异表达的前 300 个基因，该文库旨在允许对人类基因组中的每个基因进行遗传“敲除”，以及开发高通量功能基因组干细胞自我更新的测定。 2. 进行新的临床试验，以确定抑制干细胞自我更新和治疗抵抗途径是否可以改善乳腺癌患者现有的癌症治疗。新型干细胞自我更新抑制剂（Notch 和 PI3）的临床试验已计划进行。我们建议将常规治疗难治的晚期乳腺癌患者纳入其中，因为这些女性的预期临床结果较差，但她们最有可能从针对自我更新途径的治疗中受益。 3. 使用这些临床试验中的乳腺癌活检标本进行相关研究。将使用这些试验中的人类癌症活检进行相关研究，例如干细胞标记物和致瘤潜力的减少，以及相关途径抑制的下游影响。