Role of ErbB receptor signaling in regulating normal and leukemic stem cell fate

ErbB 受体信号传导在调节正常和白血病干细胞命运中的作用

• 批准号: 8679049
• 负责人: Phuong Linh Doan
• 金额: $ 12.79万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-09 至 2019-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8679049
• 关键词: Acute Myelocytic Leukemia; Acute leukemia; Adult; Aftercare; Alleles; Apoptosis; Apoptotic; Award; Blood; Bone Marrow; Bone Marrow Aspiration; Bone Marrow Cells; CD34 gene; Cancer Biology; Cancer Patient; Cell Cycle; Cell Death; Cell Maintenance; Cell Proliferation; Cells; Cessation of life; Data; Development; Diagnosis; Disease; Dose; Elements; Endothelial Cells; Epidermal Growth Factor; Epidermal Growth Factor Receptor; Exposure to; Fluorouracil; Genes; Genetic; Growth; Growth Factor; Health; Hematopoietic; Hematopoietic Cell Growth Factors; Hematopoietic System; Hematopoietic stem cells; Human; In Vitro; Incidence; Injury; Internal Ribosome Entry Site; Knockout Mice; Laboratories; Ligands; Malignant Neoplasms; Measures; Mediating; Modeling; Mus; Myelosuppression; Natural regeneration; Oncogenes; Patients; Phosphorylation; Radiation; Radioprotection; Receptor Activation; Receptor Signaling; Recovery; Recurrent disease; Refractory; Refractory Disease; Relapse; Resistance; Retroviridae; Role; Sampling; Serum; Signal Pathway; Signal Transduction; Small Interfering RNA; Stem cell transplant; Stem cells; Structure; Time; Transplantation; Tumor Burden; United States; Whole-Body Irradiation; base; cancer stem cell; cell growth; chemotherapy; cytokine; estrogen-related receptor; gain of function; improved; in vivo; injury and repair; insight; lapatinib; leukemia; leukemic stem cell; leukemogenesis; malignant breast neoplasm; novel; overexpression; phase 1 study; receptor; reconstitution; response; self-renewal; stem; stem cell fate; therapeutic target; therapy resistant

DESCRIPTION (provided by applicant): Limitations in cancer cure are due to both therapy-related complications such as myelosuppression and disease relapse due in part to cancer stem cells. To shorten the duration of myelosuppression, improved understanding of bone marrow injury and repair mechanisms could identify novel stem cell growth factors. Historically, the search for hematopoietic growth factors has focused on intrinsic signaling mechanisms, but we have sought to identify extrinsic signaling mechanisms that regulate hematopoietic stem cell (HSC) regeneration. Based on a cytokine array of secreted factors from the bone marrow of radioprotected mice bearing deletions of pro-apoptotic genes Bak and Bax, we identified elevated levels of epidermal growth factor (EGF). Our preliminary results show for the first time that HSCs express EGF receptor (EGFR), and activation of EGFR accelerates HSC regeneration after radiation. Since HSCs and leukemia stem cells (LSCs) share common signaling pathways, we screened for EGFR (ErbB1) and ErbB2, 3, and 4 in 10 patient samples with acute myeloid leukemia (AML). We detected ErbB2 overexpression, ligand-independent phosphorylation of ErbB2, and truncated forms of ErbB2 in primary AML cells. Extrapolating from ErbB2+ breast cancer biology, we know that alternate, truncated forms of ErbB2 are functional in breast cancer, and targeted therapies to inhibit ErbB2 signaling has successfully decreased tumor burden in ErbB2+ breast cancer. We expect that modulation of ErbB2 signaling will decrease LSC burden as well. To further investigate these findings, we propose two specific aims: 1. Determine the function of EGFR in regulating HSC regeneration after myelosuppression and 2. Determine to what extent ErbB2 signaling governs LSC self-renewal and sensitivity to chemotherapy. Our approach in Aim 1 is to genetically delete EGFR in Vav+ hematopoietic cells. Following exposure to radiation or chemotherapy with 5-fluorouracil, we will measure hematopoietic stem/progenitor cell content and cellular responses (i.e., cell death, cell cycle, and cell proliferation) in EGFR-deficient mice compared to control mice. We expect that deficiency of EGFR will result in substantial delays of hematopoietic recovery and will determine whether the deletion of PUMA in EGFR-deficient mice is sufficient to rescue HSCs from radiation-induced death. Therefore, EGFR signaling could be a therapeutic target to accelerate stem cell regeneration in cancer patients or those undergoing stem cell transplantation. In Aim 2, our approach is to pharmacologically and genetically modulate ErbB2 signaling and determine how ErbB2 inhibition decreases LSC burden in combination with chemotherapy. Since ErbB2 is a well-established oncogene in breast cancer, we will determine whether ErbB2 enforced activation in HSCs is sufficient to accelerate the onset of AML in a genetically-defined model of AML. In summary, we have strong preliminary evidence that EGFR/ErbB2 signaling is crucial in HSC and LSC maintenance and regeneration. Completion of these aims will further elucidate the mechanisms by which EGFR signaling accelerates HSC regeneration and provide insights into the role of ErbB2 in promoting leukemogenesis.

描述（由申请人提供）：癌症治愈的局限性是由于与治疗相关的并发症（例如骨髓抑制）和部分由癌症干细胞引起的疾病复发造成的。为了缩短骨髓抑制的持续时间，提高对骨髓损伤和修复机制的了解可以识别新的干细胞生长因子。从历史上看，对造血生长因子的研究主要集中在内在信号传导机制上，但我们一直试图确定调节造血干细胞（HSC）再生的外在信号传导机制。基于删除促凋亡基因 Bak 和 Bax 的辐射防护小鼠骨髓中分泌因子的细胞因子阵列，我们发现表皮生长因子 (EGF) 水平升高。我们的初步结果首次表明HSC表达EGF受体（EGFR），并且EGFR的激活加速了放射后HSC的再生。由于 HSC 和白血病干细胞 (LSC) 具有共同的信号通路，因此我们在 10 名急性髓系白血病 (AML) 患者样本中筛选了 EGFR (ErbB1) 和 ErbB2、3 和 4。我们在原代 AML 细胞中检测到 ErbB2 过表达、ErbB2 的配体独立磷酸化以及 ErbB2 的截短形式。从 ErbB2+ 乳腺癌生物学推断，我们知道 ErbB2 的替代、截短形式在乳腺癌中发挥作用，抑制 ErbB2 信号传导的靶向治疗已成功降低 ErbB2+ 乳腺癌的肿瘤负担。我们预计 ErbB2 信号传导的调制也将减少 LSC 负担。为了进一步研究这些发现，我们提出了两个具体目标：1. 确定 EGFR 在骨髓抑制后调节 HSC 再生中的功能；2. 确定 ErbB2 信号在多大程度上控制 LSC 自我更新和对化疗的敏感性。我们的目标 1 的方法是从基因上删除 Vav+ 造血细胞中的 EGFR。在接受 5-氟尿嘧啶放疗或化疗后，我们将测量 EGFR 缺陷小鼠与对照小鼠相比的造血干/祖细胞含量和细胞反应（即细胞死亡、细胞周期和细胞增殖）。我们预计EGFR缺陷将导致造血恢复的显着延迟，并将确定EGFR缺陷小鼠中PUMA的缺失是否足以挽救HSC免于辐射诱导的死亡。因此，EGFR 信号传导可能成为加速癌症患者或接受干细胞移植的患者干细胞再生的治疗靶点。在目标 2 中，我们的方法是通过药理学和基因调节 ErbB2 信号传导，并确定 ErbB2 抑制与化疗相结合如何降低 LSC 负担。由于 ErbB2 是乳腺癌中公认的癌基因，因此我们将确定 HSC 中 ErbB2 的强制激活是否足以在 AML 基因定义模型中加速 AML 的发病。总之，我们有强有力的初步证据表明 EGFR/ErbB2 信号传导对于 HSC 和 LSC 的维持和再生至关重要。这些目标的完成将进一步阐明 EGFR 信号传导加速 HSC 再生的机制，并深入了解 ErbB2 在促进白血病发生中的作用。