Connexin hemichannels in suppression of breast cancer bone metastasis

连接蛋白半通道抑制乳腺癌骨转移

• 批准号: 9030104
• 负责人: Jean X Jiang
• 金额: $ 35.59万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-01 至 2021-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9030104
• 关键词: ATP Receptors; Adverse effects; Anchorage-Independent Growth; Attenuated; Biochemical; Biological Assay; Biology; Blocking Antibodies; Bone Diseases; Breast Cancer Cell; Breast Cancer Treatment; Cancer Etiology; Cell physiology; Cells; Clinical; Collaborations; Complication; Connexin 43; Connexins; Data; Defense Mechanisms; Development; Disseminated Malignant Neoplasm; Down-Regulation; Drug Targeting; Genes; Goals; Growth; Housing; Human; Imaging Techniques; In Vitro; Intervention; Knockout Mice; Laboratories; Malignant Neoplasms; Mechanical Stimulation; Mechanics; Mediator of activation protein; Metastatic Neoplasm to the Bone; Metastatic breast cancer; Microtubule Stabilization; Microtubules; Modality; Modeling; Mus; Neoplasm Metastasis; Osteoblasts; Osteoclasts; Osteocytes; Outcome; Patients; Pharmaceutical Preparations; Physical Exercise; Physical activity; Play; Purinoceptor; Receptor Signaling; Research; Research Activity; Role; Sampling; Site; Specimen; Structure; Testing; The Sun; Time; Tissues; base; bisphosphonate; bone; bone cell; bone strength; calmodulin-dependent protein kinase II; cancer cell; cell type; experience; in vivo; knock-down; malignant breast neoplasm; migration; mouse model; new therapeutic target; novel; optical imaging; paracrine; public health relevance; receptor; receptor-mediated signaling; release factor; shear stress; stathmin; targeted biomarker; tibia; tumor

 DESCRIPTION (provided by applicant): Bone is a major site for the preferential metastasis by advanced breast cancers. Bone metastases by breast cancers cause deadly complications and there is an unmet need for efficacious intervention with minimal side effect. The majority of previous studies have primarily focused on metastasized cancer cells or tumor supporting bone microenvironments. Here we propose to investigate the intrinsic anti-cancer metastatic potentials of the osteocytes, the most abundant bone cell type in the bone. Connexin (Cx) 43 hemichannels are richly present in osteocytes. Our preliminary study showed that the opening of Cx43 hemichannels by either bisphosphonate drugs or mechanical stimulation inhibited migration and anchorage-independent growth of breast cancer cells. Moreover, breast cancer bone metastasis appears to be augmented in osteocyte-specific Cx43 knockout mice when compared to wild-type controls. As such, we hypothesize that active Cx43 hemichannels in osteocytes release ATP and ATP acting in a paracrine manner activates purinergic receptor signaling in breast cancer cells, leading to the suppression of breast cancer bone metastasis. The goal is to establish the importance of osteocytic Cx43 hemichannels as a potential, novel drug target for the treatment. In this proposal, first, we will test the hypothesis that active osteocytic Cx43 hemichannels inhibit breast cancer cell metastasis. The effect of Cx43 hemichannel inhibition on breast cancer bone metastasis will be examined in vivo using in-house developed Cx43-deficient mouse models and hemichannel-specific blocking antibodies. The cell-based studies will be used to dissect the effect of osteocytic Cx43 hemichannels on various subtypes of breast cancer cells. Second, we will test the hypothesis that osteocytic Cx43 hemichannels activated by mechanical loading, associated with physical exercise, plays a critical role in the inhibition of breast cancer bone metastasis. We will apply mechanical loading through flow shear stress in vitro and tibial loading in vivo to assess the functional involvement of osteocytic Cx43-hemichannels in breast cancer migration and bone metastasis, and on bone cell function and bone strength, as the latter could serve as a complementary defense mechanism against bone metastasis. Third, we will test the hypothesis that P2X7 receptor in breast cancer cells activated by ATP released by osteocytic Cx43 hemichannels is responsible for the suppression of bone metastasis by first investigating the roles of ATP and P2X7 purinergic receptor, and followed by studying the underlying mechanism concerning how the activation of P2X7 receptor-mediated signaling inhibits breast cancer cell function and if down-regulation of this mechanism is more prevalent in clinical samples associated with bone metastases. Through a unique collaboration with the laboratories of the two PIs with their strong, complementary expertise, the proposed studies are expected to reveal a novel, inhibitory mechanism in the suppression of breast cancer bone metastasis, and should make significant contributions to the discovery of new therapeutic targets for the treatment of breast cancer-induced bone metastases.

 描述（由适用提供）：骨是晚期乳腺癌首选转移的主要部位。乳腺癌的骨转移引起致命的并发症，并且对有效干预的需求很小，副作用最少。以前的大多数研究主要集中于转移性癌细胞或支持骨微环境的肿瘤。在这里，我们建议研究骨细胞的内在抗癌转移电位，骨细胞是骨骼中最丰富的骨细胞类型。连接蛋白（CX）43个半通道在骨细胞中丰富存在。我们的初步研究表明，双膦酸盐药物或机械刺激抑制乳腺癌细胞的迁移和锚固非依赖性生长的CX43半通道开放。此外，与野生型对照相比，在骨细胞特异性CX43敲除小鼠中，乳腺癌骨转移似乎增加了。因此，我们假设骨细胞中的活性CX43半通道以旁分泌方式释放ATP和ATP会激活乳腺癌细胞中的嘌呤能受体信号传导，从而抑制乳腺癌骨转移。目的是确定骨细胞CX43半通道的重要性，作为该治疗的潜在新型药物靶标。在此提案中，首先，我们将测试活性骨细胞CX43半通道抑制乳腺癌细胞转移的假设。 CX43半通道抑制对乳腺癌骨转移的影响将在体内使用内部开发的CX43缺陷小鼠模型和半通道特异性阻断抗体进行检查。基于细胞的研究将用于剖析骨细胞CX43半通道对乳腺癌细胞各种亚型的影响。其次，我们将检验以下假设：骨细胞CX43半通道通过与体育锻炼相关的机械载荷激活，在抑制乳腺癌骨转移中起着至关重要的作用。我们将通过体外的体外和胫骨负荷进行机械载荷来评估骨细胞CX43-光通道在乳腺癌迁移和骨转移以及骨细胞功能和骨骼强度上的功能参与，因为后者可以用作抗骨转移的完整防御机制。第三，我们将检验以下假说：骨细胞Cx43释放的ATP激活的p2x7受体通过首先研究ATP和P2X7嘌呤能受体的作用，从而抑制骨转移，并通过研究P2X7的乳腺癌癌症，并在P2X7的乳腺癌中进行癌症，并抑制P2X7的乳腺疾病，并抑制了P2X7受体机制。这种机制在与骨转移相关的临床样本中更为普遍。通过与两个PI的实验室的独特合作，其强大，完整的专业知识，预计拟议的研究将揭示一种新型的抑制性机制，以抑制乳腺癌骨转移，并应为发现新的治疗靶标做出重大贡献，以治疗乳腺癌诱导的骨转移酶。