PTHrP Modulation of TRPV1 in Pain Associated with Breast Cancer Bone Metastasis

PTHrP 对 TRPV1 的调节在乳腺癌骨转移相关疼痛中的作用

• 批准号: 8397858
• 负责人: Aaron David Mickle
• 金额: $ 2.82万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8397858
• 关键词: Afferent Neurons; Analgesics; Behavior assessment; Biochemical; Body Temperature; Bone Pain; Bone neoplasms; Breast; Breast Cancer Cell; Case Study; Chronic; Coculture Techniques; Cytolysis; Development; Diagnosis; Dose-Limiting; Drops; Electrophysiology (science); Event; Fiber; Frequencies; Gait; Goals; Human; Image; Inflammation Mediators; Inflammatory; Injection of therapeutic agent; Intervention; Ions; Lead; Limb structure; MDA MB 231; Malignant Bone Neoplasm; Malignant Neoplasms; Mammary Neoplasms; Mediating; Membrane Proteins; Metastatic Neoplasm to the Bone; Modification; Molecular; Morbidity - disease rate; Morphine; Morphine Derivatives Including Cocaine; Mus; Neoplasm Metastasis; Nerve Fibers; Neurons; Nociceptors; Nutrient; Osteoblasts; Osteoclasts; Pain; Palliative Care; Parathyroid Hormone Receptor; Patients; Pelvis; Pharmacotherapy; Phosphorylation; Physiological; Protein Biochemistry; Protein Kinase C; Proteins; Quality of life; Regimen; Role; Sensory; Series; Side; Signal Transduction; Signaling Molecule; Spinal Ganglia; Temperature; Testing; Therapeutic; Time; United States; Up-Regulation; Vanilloid; Vertebral column; Weight-Bearing state; Woman; Xenograft procedure; afferent nerve; base; bisphosphonate; bone; cancer diagnosis; cancer pain; chronic pain; grasp; in vivo; in vivo Model; inflammatory pain; insight; limb bone; long bone; malignant breast neoplasm; neurobiological mechanism; novel; pain behavior; parathyroid hormone-related protein; patch clamp; receptor; spontaneous pain; tumor; tumor growth

DESCRIPTION (provided by applicant): Breast cancer is the most frequently diagnosed cancer among women in the United States with >200,000 new cases reported every year. Aggressive forms of breast cancers most commonly metastasize to bones, which constitutes the key factor for high morbidity rate and associated suffering. Metastatic breast tumor growth in bones leads to chronic pain in the limbs, pelvis and spines, which is undermanaged with existing pain medications, mainly morphine derivatives. As palliative care is the major therapeutic goal for patients with breast cancer bone metastasis, a better understanding of signaling crosstalk between metastatic bone tumor microenvironment and the adjacent sensory nerve fibers is necessary for the development of highly efficacious analgesics for chronic bone cancer pain. Metastatic breast cancer cells secrete high levels of parathyroid hormone-related peptide (PTHrP), which act on osteoblasts and osteoclasts to induce bone lysis/destruction and subsequent release of nutrients and cell signaling molecules that stimulate tumor growth. Here I propose a novel hypothesis that PTHrP, by acting through its receptor PTH1 on sensory afferents, induce constitutive nociceptor sensitization via upregulation of activity/expression of the transient receptor potential vanilloid-1 (TRPV1) channel, which might underlie a mechanism for chronic pain associated with metastatic breast/bone cancers. The TRPV1 channel is normally activated only at noxious temperatures (e43oC). However, PTHrP acting through the PTH1 receptor could induce phosphorylation of TRPV1 protein and lead to constitutive channel activation at body temperatures (d37oC), a mechanism that could underlie chronic pain in the absence of any overt stimulation. Aim 1 of my study will determine the specific cellular signaling events that underlie PTHrP-modulation of TRPV1 channel activity/expression in sensory neurons, and nociceptor sensitization. I will utilize patch-clamp electrophysiology, Ca2+ imaging, and membrane protein biochemistry to determine the molecular mechanisms underlying TRPV1 modulation by PTHrP. Aim 2 of my study will determine the role of PTHrP-modulation of TRPV1 in sensory afferents on chronic bone pain in vivo using scid mice xenografts of human breast cancer cells, MDA-MB231-BoM-1833, that metastasize to bones when injected intracardialy. I will use a series of un-evoked/spontaneous bone-related pain behavioral assessments in these mice with metastatic breast/bone tumors. I will also utilize pharmacological inhibition of PTHrP and TRPV1 in these mice, to further confirm the contribution of PTHrP-modulation of TRPV1 in chronic bone pain associated with metastatic breast/bone tumor growth. My proposed studies will advance our understanding of how the interplay between metastatic breast/bone tumors and sensory neurons mediate chronic pain. Findings from this study will significantly contribute to the development of effective pharmacotherapies for chronic pain associated with metastatic bone cancers. PUBLIC HEALTH RELEVANCE: Chronic pain associated with bone-metastasized breast cancers significantly diminishes the quality of life for women with this metastatic form of breast cancers. Breast cancers frequently metastasize to bones and cause chronic debilitating pain, which is undermanaged with the currently available analgesic regimen. Understanding the precise neurobiological mechanisms underlying this form of chronic pain is paramount for the development of novel and effective analgesic therapeutics. Specific modulation of the activity/expression of the key pain-transducing channel TRPV1 in sensory neurons that innervate bones, by PTHrP, which is secreted at elevated levels in bone-metastasized breast tumor microenvironment, is a potential neurobiological mechanism for chronic pain, and can be targeted for the development of pharmacotherapeutics for treating such pain.)

描述（由申请人提供）：乳腺癌是美国女性中最常诊断出的癌症，每年报告的新病例超过 200,000 例。侵袭性乳腺癌最常转移至骨骼，这是高发病率和相关痛苦的关键因素。骨中转移性乳腺肿瘤的生长会导致四肢、骨盆和脊柱的慢性疼痛，而现有的止痛药物（主要是吗啡衍生物）对此治疗效果不佳。由于姑息治疗是乳腺癌骨转移患者的主要治疗目标，因此更好地了解转移性骨肿瘤微环境与邻近感觉神经纤维之间的信号串扰对于开发治疗慢性骨癌疼痛的高效镇痛药是必要的。转移性乳腺癌细胞分泌高水平的甲状旁腺激素相关肽（PTHrP），作用于成骨细胞和破骨细胞，诱导骨质溶解/破坏，随后释放营养物质和细胞信号分子，刺激肿瘤生长。在这里，我提出了一个新的假设，即 PTHrP 通过其受体 PTH1 作用于感觉传入，通过上调瞬时受体电位 vanilloid-1 (TRPV1) 通道的活性/表达来诱导伤害性感受器敏化，这可能是慢性疼痛的机制基础与转移性乳腺癌/骨癌相关。 TRPV1 通道通常仅在有害温度 (e43oC) 下激活。然而，PTHrP 通过 PTH1 受体起作用，可以诱导 TRPV1 蛋白磷酸化，并导致体温 (d37oC) 下的组成型通道激活，这种机制可能是在没有任何明显刺激的情况下产生慢性疼痛的机制。我的研究目标 1 将确定感觉神经元中 TRPV1 通道活性/表达的 PTHrP 调节和伤害感受器敏化背后的特定细胞信号转导事件。我将利用膜片钳电生理学、Ca2+ 成像和膜蛋白生物化学来确定 PTHrP 调节 TRPV1 的分子机制。我的研究的目标 2 将使用人类乳腺癌细胞 MDA-MB231-BoM-1833 的 scid 小鼠异种移植物来确定 TRPV1 的 PTHrP 调节在感觉传入中对体内慢性骨痛的作用，该细胞在心内注射时会转移到骨骼。我将对这些患有转移性乳腺/骨肿瘤的小鼠进行一系列非诱发/自发的骨相关疼痛行为评估。我还将在这些小鼠中利用 PTHrP 和 TRPV1 的药理学抑制作用，以进一步确认 PTHrP 调节 TRPV1 在与转移性乳腺/骨肿瘤生长相关的慢性骨痛中的作用。我提出的研究将增进我们对转移性乳腺/骨肿瘤和感觉神经元之间如何相互作用介导慢性疼痛的理解。这项研究的结果将极大地有助于开发治疗与转移性骨癌相关的慢性疼痛的有效药物疗法。 公共卫生相关性：与骨转移性乳腺癌相关的慢性疼痛显着降低患有这种转移性乳腺癌的女性的生活质量。乳腺癌经常转移到骨骼并引起慢性衰弱性疼痛，而目前可用的镇痛疗法对此治疗效果不佳。了解这种慢性疼痛背后的精确神经生物学机制对于开发新型有效的镇痛疗法至关重要。 PTHrP 在骨转移乳腺肿瘤微环境中以升高的水平分泌，对支配骨骼的感觉神经元中关键疼痛传导通道 TRPV1 的活性/表达进行特异性调节，是慢性疼痛的潜在神经生物学机制，并且可以通过 PTHrP 进行特异性调节。成为开发治疗此类疼痛的药物疗法的目标。）