Akt/CREB signaling: Target for prostate cancer

描述(由申请人提供)： 项目摘要尽管手术和治疗方法取得了进步，但退伍军人患前列腺癌的风险是非退伍军人的4倍。因此，在这一人群中预防或延缓临床重大疾病的发展和进展的新策略对于前列腺癌的成功治疗至关重要。这项VA-MERIT提案的目标是开发一种安全有效的策略，使用一种名为NexrutineR的新型树皮提取物来治疗具有临床意义的前列腺癌。这是基于我们实验室已发表和初步未发表的研究证明：(I)NexrutineR干预可抑制类似于人类的前列腺癌的临床前动物模型的早期肿瘤发展；(Ii)NexrutineR治疗可降低前列腺癌细胞中Akt的激活、CREB和NF：B的转录活性以及抗凋亡蛋白Flip的表达；(Iii)Myristoylated Akt的过表达可保护前列腺癌细胞免受NexrutineR诱导的生长抑制。初步结果还表明，在NexrutineR作用2小时内，pmTOR(2448)和pakt(473)的蛋白水平降低；这表明Akt/mTOR信号在Nexrutine R诱导的生物学活性中发挥了作用。尽管有这些有希望的结果，但mTORC2/Akt信号和Akt下游的信号通路，包括CREB在NexrutineR诱导的抑制细胞增殖/存活和诱导细胞凋亡中的确切作用仍有待确定。此外，目前尚不清楚NexrutineR是仅在预防早期前列腺癌方面有效，还是对其他阶段的前列腺癌有效。此外，我们实验室和其他研究人员发表的研究表明，在前列腺癌患者中，FLIP、CREB、Akt、NF：B的表达与肿瘤分级之间存在良好的相关性。这些数据支持这样一个概念，即相当数量的患有高级别前列腺癌的VA患者可能受益于针对FLIP、CREB、Akt、NF：B信号或激活这些分子的通路的策略。到目前为止，还没有研究检验这些关键信号通路联合靶向治疗前列腺癌的可能性。我们设计了实验来填补这些关键的空白，使用了最先进的方法，包括用于监测动物肿瘤发展的磁共振成像(MRI)、siRNA方法、芯片分析以及标准的分子和生化方法。尽管多组分方法已成功地应用于结核病、艾滋病和白血病等疾病的治疗，但此类策略尚未被充分利用于前列腺癌的治疗。因此，我们的方法同时针对在前列腺癌进展中起关键作用的mTORC2/Akt/mTORC1和Akt/NF：B介导的信号通路，同时使用安全和经济有效的草药补充剂是新颖和创新的。这些研究的结果可能会提供机制数据和详细的临床前评估，为NexrutineR治疗VA患者前列腺癌的临床评估奠定基础。 公共卫生相关性： 项目简介：对于老年退伍军人来说，一个关键的医疗保健问题是转移性激素难治性前列腺癌，它是前列腺癌相关死亡的主要原因。尽管没有详细探讨，但有人认为，退伍军人更容易受到战争期间各种有毒化学品和油井火灾产生的烟雾的影响。此外，随着退伍军人预期寿命的延长，前列腺癌仍将是一个主要的健康问题。因此，开发新的无毒治疗方式对于保护现有和未来的武装部队人员至关重要。考虑到前列腺癌的这些问题和已知的异质性，同时靶向在前列腺癌发生过程中起关键/主要作用的多个关键信号通路将在控制发病率和死亡率方面具有巨大的优势和影响。此外，这些数据将为更好地为患有前列腺癌的退伍军人群体设计未来的临床试验提供关键的见解。

DESCRIPTION (provided by applicant): Project Summary Despite advances in surgical and therapeutic approaches, veterans have a 4-times higher risk for developing prostate cancer compared with non-veterans. Therefore novel strategies to prevent or delay development and progression of clinically significant disease in this population are critical for successful management of prostate cancer. The goal of this VA-Merit proposal is to develop a safe and effective strategy for management of clinically significant prostate cancer using a novel bark extract namely NexrutineR. This is based on strong published and preliminary unpublished studies from our laboratory demonstrating (i) NexrutineR intervention inhibits early stage tumor development in a preclinical animal model that develops prostate cancer akin to humans; (ii) NexrutineR treatment reduces Akt activation, transcriptional activity of CREB and NF:B and expression of antiapoptotic protein FLIP in prostate cancer cells and (iii) overexpression of myristoylated Akt protects prostate cancer cells from NexrutineR - induced growth inhibition. Preliminary results also show that reduction in the protein levels of pmTOR (2448) and pAkt (473) within 2h of NexrutineR; implicating a role for Akt/mTOR signaling in NexrutineR-induced biological activities. Despite such promising results, the precise role of mTORC2/Akt signaling and signaling pathways downstream of Akt, including CREB in NexrutineR-induced inhibition of cell proliferation/survival and induction of apoptosis remains to be established. Further it is not known whether NexrutineR is effective only in preventing early stage prostate tumors or it will be effective in other stages of prostate cancer. In addition, published studies from our laboratory and other investigators demonstrate a good correlation between expression of FLIP, CREB, Akt, NF:B and tumor grade in human prostate cancer patients. This data supports the concept that a substantial number of VA patients with high grade prostate cancer may benefit from strategies targeting FLIP, CREB, Akt, NF:B signaling or pathways that activate these molecules. To date no studies have examined the potential for combined targeting of these critical signaling pathways for prostate cancer management. We have designed experiments to fill these critical gaps using state-of-the-art methodologies including magnetic resonance imaging (MRI) for monitoring tumor development in animals, siRNA approaches, ChIP analysis in addition to standard molecular and biochemical approaches. Although multicomponent approach has been successfully applied in the treatment of diseases such as tuberculosis, AIDS and leukemia, such strategies have not been exploited fully for prostate cancer management. Therefore our approach targeting mTORC2/Akt/mTORC1 and Akt/NF:B- mediated signaling pathways simultaneously that play a critical role in prostate cancer progression while using a safe and cost-effective herbal supplement is novel and innovative. Results from these studies will likely provide mechanistic data and a detailed preclinical evaluation, setting the stage for the clinical assessment of NexrutineR against prostate cancer in VA patients. PUBLIC HEALTH RELEVANCE: Project Narrative: A critical health care issue for the aging Veteran population is metastatic hormone refractory prostate cancer which accounts for most of the prostate cancer associated fatality. Although not explored in detail, it has been suggested that Veterans are more susceptible due to extended exposure to various toxic chemicals and smoke from oil well fires during war. In addition with increasing life expectancy of the Veteran population, prostate cancer will continue to be a major health problem. Therefore developing new non toxic treatment modalities are critical for protecting current and future armed forces personnel. Considering these problems and the known heterogeneity of prostate cancer, simultaneously targeting multiple critical signaling pathways that play a critical/major role during prostate carcinogenesis will have tremendous advantage and impact in keeping morbidity and mortality at bay. In addition these data will provide key insights for better design of future clinical trials for Veterans population who has developed prostate cancer.