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: 9129450
• 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/9129450
• 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; 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; TP53 gene; 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; radioprotected; radiosensitive; receptor; reconstitution; response; self-renewal; stem; stem cell fate; targeted treatment; 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治疗相关的并发症，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，提高对骨髓损伤和修复机制的理解可以识别新的干细胞生长因子。从历史上看，造血生长因子的研究集中在内在的信号传导机制，但我们试图确定调控造血干细胞（HSC）再生的外在信号传导机制。基于一个细胞因子阵列的分泌因子从骨髓的放射保护小鼠轴承缺失的促凋亡基因巴克和Bax，我们确定了表皮生长因子（EGF）的水平升高。我们的初步研究结果首次表明，HSC表达EGF受体（EGFR），EGFR的激活加速了辐射后HSC的再生。由于HSC和白血病干细胞（LSC）共享共同的信号传导途径，我们在10例急性髓性白血病（AML）患者样本中筛选EGFR（ErbB 1）和ErbB 2、3和4。我们在原代AML细胞中检测到ErbB 2过表达、ErbB 2的配体非依赖性磷酸化和ErbB 2的截短形式。从ErbB 2+乳腺癌生物学推断，我们知道ErbB 2的替代、截短形式在乳腺癌中起作用，抑制ErbB 2信号传导的靶向治疗已成功降低ErbB 2+乳腺癌的肿瘤负荷。我们预期ErbB 2信号的调制也将降低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在骨髓抑制后调控HSC再生中的作用;确定ErbB 2信号在多大程度上控制LSC的自我更新和对化疗的敏感性。我们在目标1中的方法是在Vav+造血细胞中遗传缺失EGFR。在暴露于放射或5-氟尿嘧啶化疗后，我们将测量造血干/祖细胞含量和细胞反应（即，细胞死亡、细胞周期和细胞增殖）。我们预期EGFR的缺乏将导致造血恢复的实质性延迟，并将确定EGFR缺陷小鼠中HSCs A的缺失是否足以拯救HSC免于辐射诱导的死亡。因此，EGFR信号传导可能是加速癌症患者或接受干细胞移植的患者的干细胞再生的治疗靶点。在目标2中，我们的方法是研究和遗传调节ErbB 2信号传导，并确定ErbB 2抑制如何与化疗联合降低LSC负荷。由于ErbB 2是乳腺癌中公认的癌基因，因此我们将确定ErbB 2在HSC中的强制激活是否足以加速遗传定义的AML模型中的AML发病。总之，我们有强有力的初步证据表明EGFR/ErbB 2信号传导在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信号传导加速HSC再生的机制，并为ErbB 2在促进白血病发生中的作用提供见解。