The GABA-B receptor is a novel drug target for pancreatic cancer

GABA-B受体是胰腺癌的新型药物靶点

• 批准号: 7872882
• 负责人: Hildegard M. Schuller
• 金额: $ 27.27万
• 依托单位: UNIVERSITY OF TENNESSEE KNOXVILLE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7872882
• 关键词: Adenocarcinoma; Adenocarcinoma Cell; Adenylate Cyclase; Adrenergic Agents; Adrenergic beta-Antagonists; Agonist; Aminobutyric Acids; Angiogenic Factor; Apoptotic; Area; Biological; Breast; Butanones; Cancer Etiology; Cancer Prognosis; Cancerous; Cell Line; Cell Proliferation; Cells; Cessation of life; Cleaved cell; Clinical Trials; Colon; Complex; Country; Cyclic AMP; Data; Development; Diabetes Mellitus; Diagnosis; Disease; Drug Delivery Systems; EGF gene; Effectiveness; Enzymes; Epidermal Growth Factor Receptor; Epinephrine; Epithelial Cells; G-Protein-Coupled Receptors; Gefitinib; Gene Silencing; Genes; Glutamate Decarboxylase; Goals; Growth; Growth Factor; Guide prevention; Hamsters; Hand; Human; Human Cell Line; Hypermethylation; Immunohistochemistry; In Vitro; Laboratories; Lead; Malignant Neoplasms; Malignant neoplasm of pancreas; Mus; National Cancer Institute; Neoplasm Metastasis; Neurotransmitters; Nicotine; Nicotinic Receptors; Nitrosamines; Norepinephrine; Nude Mice; Ovary; PTGS2 gene; Pancreas; Pancreatic Ductal Adenocarcinoma; Pancreatic duct; Pancreatitis; Pathway interactions; Prevention; Prevention therapy; Production; Propranolol; Prostate; Publishing; Receptor Activation; Regulation; Research; Resistance; Risk Factors; Role; Signal Transduction; Smoke; Smoking; Staging; Starvation; Stomach; Stress; Testing; Time; Tissues; Transactivation; Translating; Woman; Xenograft procedure; adrenergic; base; celecoxib; cell motility; combat; effective therapy; gamma-Aminobutyric Acid; gemcitabine; improved; in vivo; inhibitor/antagonist; men; migration; mortality; novel; overexpression; pre-clinical; promoter; public health relevance; receptor; response; treatment strategy; tumorigenic

DESCRIPTION (provided by applicant): Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer mortality in Western countries and smoking, diabetes, and pancreatitis are risk factors. The prognosis of this cancer is extremely poor due to its resistance to available therapies and extensive metastasis. New strategies to combat this deadly disease are thus urgently needed and are among priority areas of research identified by the National Cancer Institute. The long-term goal of this project is to develop novel and effective strategies for the treatment and prevention of PDAC. The current project takes advantage of our discovery that beta-adrenoreceptors regulate the growth of human PDAC cell lines and their cells of origin, pancreatic duct epithelial cells. Stimulation of these G- protein coupled receptors by agonists induced signaling via adenylyl cyclase=>cAMP=>PKA=>CREB and transactivated the EGF pathway in a PKA-dependent manner. Isoroterenol additionally stimulated cell migration and had strong anti-apoptotic effects as evidenced by suppression of starvation-induced cleaved casapse 3. GABA and baclophen had strong inhibiting effects on all these responses and additionally reduced proliferation, migration of untreated cells. In support of these in vitro findings, nicotine-induced increase in systemic stress neurotransmitters adrenaline and noradrenaline strongly stimulated the growth of PDAC xenografts, induced p-CREB and p-ERK1/2 in xenograft cells while suppressing the GABA synthesizing enzyme GAD65 and GABA. Treatment of the mice with GABA completely blocked xenograft growth while returning levels of p-CREB, p-ERK1/2, GAD and GABA to normal levels. These data suggest the GABAB receptor as a novel drug target for the treatment and prevention of PDAC. To test this hypothesis we propose four specific aims: Specific aim 1: To evaluate the anti-tumorigenic effects of GABA and the GABAB receptor agonist baclophen on early and advanced stages of PDAC xenograft development in nude mice in the presence and absence of stress neurotransmitter stimulation in response to nicotine and NNK. Specific aim 2: To test the hypothesis that the observed suppression of GAD65 and GABA in nicotine and NNK-treated PDAC xenografts is caused by gene promoter hypermethylation of GAD65, that GABA reverses these effects and to verify these mechanism of gene silencing and reversal in vitro in pancreatic duct epithelial cells. Specific aim 3: To test the hypothesis that the antitumorigenic effects of gefitinib and gemcitabine on PDAC cells are reduced in the presence of stress neurotransmitter stimulation in vitro and in PDAC xenografts and that combination treatments with either agent plus GABA or baclophen improves their effectiveness. Specific aim 4: To assess the effects of the beta-blocker propranolol or the COX-2 inhibitor celecoxib in vitro and in PDAC xenografts with and without stimulation by stress neurotransmitters, and to compare their effectiveness to that of GABA and baclophen. Data to be generated by this project may lead to the successful prevention and treatment of smoking- associated PDAC in a marker-guided fashion with GABA-ergic agents and generate a better understanding of the complex mechanisms of action of stimulating and inhibiting neurotransmitters in the regulation of PDAC. Since GABA and baclophen are already approved for the treatment of non-cancerous conditions in humans, results of this research can be rapidly translated into clinical trials. PUBLIC HEALTH RELEVANCE: Pancreatic cancer is the fourth leading cause of cancer death with mortality near 100% within one year of diagnosis because it does not respond to existing therapies and metastasizes extensively. New strategies to combat this deadly disease are thus urgently needed. Data presented in this project along with known biological effects of risk factors for pancreatic cancer (smoking, diabetes, pancreatitis) suggest that hyperactive cAMP-dependent signaling caused by an increase in the stress neurotransmitters adrenaline and noradrenaline stimulates pancreatic cancer development and progression while at the same time the pancreatic production of gamma-aminobutyric acid (GABA), which normally controls the activity of these receptors via activation of the inhibitory GABAB receptor, is reduced. Based on this novel concept, we propose the GABAB receptor as a novel drug target for the therapy and prevention of pancreatic cancer. In vitro and in vivo studies proposed under this project will provide a preclinical basis for the use of GABA-ergic agents for the effective therapy and prevention of pancreatic cancer.

描述（由申请人提供）：胰腺导管腺癌（PDAC）是西方国家第四大癌症死亡原因，吸烟、糖尿病和胰腺炎是危险因素。由于对现有疗法的抵抗力和广泛的转移，这种癌症的预后极差。因此，迫切需要对抗这种致命疾病的新策略，并且是国家癌症研究所确定的优先研究领域之一。该项目的长期目标是开发治疗和预防 PDAC 的新颖有效的策略。当前的项目利用了我们的发现，即 β-肾上腺素受体调节人 PDAC 细胞系及其来源细胞——胰管上皮细胞的生长。激动剂对这些G蛋白偶联受体的刺激通过腺苷酸环化酶=>cAMP=>PKA=>CREB诱导信号传导，并以PKA依赖性方式反式激活EGF途径。异甾烯醇还刺激细胞迁移，并具有强烈​​的抗凋亡作用，这通过抑制饥饿诱导的裂解的casapse 3来证明。GABA和巴氯芬对所有这些反应具有强烈的抑制作用，并且还减少了未处理细胞的增殖和迁移。为了支持这些体外研究结果，尼古丁诱导的全身应激神经递质肾上腺素和去甲肾上腺素的增加强烈刺激了PDAC异种移植物的生长，诱导异种移植细胞中的p-CREB和p-ERK1/2，同时抑制GABA合成酶GAD65和GABA。用 GABA 治疗小鼠完全阻断了异种移植物的生长，同时使 p-CREB、p-ERK1/2、GAD 和 GABA 的水平恢复到正常水平。这些数据表明 GABAB 受体作为治疗和预防 PDAC 的新药物靶点。为了检验这一假设，我们提出了四个具体目标： 具体目标 1：评估 GABA 和 GABAB 受体激动剂巴氯芬对存在和不存在应激神经递质刺激的裸鼠 PDAC 异种移植物发育的早期和晚期阶段的抗肿瘤作用对尼古丁和 NNK 的反应。具体目标 2：检验尼古丁和 NNK 处理的 PDAC 异种移植物中观察到的 GAD65 和 GABA 抑制是由 GAD65 基因启动子高甲基化引起的假设，GABA 逆转这些效应，并在体外验证这些基因沉默和逆转机制存在于胰管上皮细胞中。具体目标 3：检验以下假设：在体外和 PDAC 异种移植物中存在应激神经递质刺激的情况下，吉非替尼和吉西他滨对 PDAC 细胞的抗肿瘤作用会降低，并且与任一药物加 GABA 或巴氯芬的联合治疗可提高其有效性。具体目标 4：评估 β 受体阻滞剂普萘洛尔或 COX-2 抑制剂塞来昔布在体外以及在有或没有应激神经递质刺激的 PDAC 异种移植物中的作用，并将其与 GABA 和巴氯芬的有效性进行比较。该项目生成的数据可能会导致使用 GABA 能药物以标记引导方式成功预防和治疗与吸烟相关的 PDAC，并更好地了解调节中刺激和抑制神经递质的复杂作用机制的 PDAC。由于 GABA 和巴氯芬已被批准用于治疗人类非癌症疾病，因此这项研究的结果可以迅速转化为临床试验。公共健康相关性：胰腺癌是癌症死亡的第四大原因，诊断后一年内死亡率接近 100%，因为它对现有疗法没有反应并且广泛转移。因此，迫切需要对抗这种致命疾病的新策略。该项目中提供的数据以及胰腺癌危险因素（吸烟、糖尿病、胰腺炎）的已知生物效应表明，应激神经递质肾上腺素和去甲肾上腺素增加引起的过度活跃的 cAMP 依赖性信号传导会刺激胰腺癌的发生和进展。同时，胰腺产生的 γ-氨基丁酸 (GABA) 减少，而 GABA 通常通过激活抑制性 GABAB 受体来控制这些受体的活性。基于这个新概念，我们提出GABAB受体作为治疗和预防胰腺癌的新药物靶点。该项目提出的体外和体内研究将为使用 GABA 能药物有效治疗和预防胰腺癌提供临床前基础。