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）：癌症治疗的局限性归因于治疗相关并发症，例如骨髓抑制和疾病复发，部分原因是癌症干细胞。为了缩短骨髓抑制的持续时间，对骨髓损伤和修复机制的理解有所提高，可以鉴定出新型的干细胞生长因子。从历史上看，人们对造血生长因子的搜索集中在固有的信号传导机制上，但我们试图确定调节造血干细胞（HSC）再生的外部信号传导机制。基于来自促凋亡基因的缺失的放射性保护小鼠的骨髓的细胞因子阵列，我们确定了表皮生长因子（EGF）的升高水平。我们的初步结果首次表明HSC表达EGF受体（EGFR），EGFR的激活会加速放射后HSC再生。由于HSC和白血病干细胞（LSC）共享共同的信号通路，因此我们筛选了EGFR（ERBB1）和ERBB2、3和4的10位患者样品中的ERBB2、3和4，患有急性髓样白血病（AML）。我们检测到ERBB2的过表达，ERBB2的非配体无依赖性磷酸化以及原代AML细胞中ERBB2的截断形式。从ERBB2+乳腺癌生物学中推断出来，我们知道ERBB2的交替，截断形式在乳腺癌中起作用，并且抑制ERBB2信号传导的靶向疗法成功地减轻了ERBB2+乳腺癌的肿瘤负担。我们预计ERBB2信号的调制也会减轻LSC负担。为了进一步研究这些发现，我们提出了两个具体的目的：1。确定EGFR在骨髓抑制后调节HSC再生的功能和2。确定ERBB2信号在多大程度上控制LSC自我更新和对化学疗法的敏感性。我们在目标1中的方法是在VAV+造血细胞中遗传删除EGFR。与对照小鼠相比，在接触5-氟尿嘧啶的放射或化学疗法后，我们将测量EGFR缺陷型小鼠中的造血干/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的缺乏将导致造血恢复的大量延迟，并确定EGFR缺陷小鼠中PUMA的缺失是否足以使HSC免于辐射诱导的死亡。因此，EGFR信号传导可能是癌症患者或接受干细胞移植患者加速干细胞再生的治疗靶标。在AIM 2中，我们的方法是在药理和遗传上调节ERBB2信号传导，并确定ERBB2抑制如何与化学疗法结合使用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中的ERBB2强化是否足以加速AML遗传定义模型中AML的发作。总而言之，我们有强有力的初步证据，表明EGFR/ERBB2信号在HSC和LSC的维持和再生中至关重要。这些目标的完成将进一步阐明EGFR信号加速HSC再生的机制，并提供有关ERBB2在促进白血病发生中作用的见解。