Development of a combination therapy for the treatment of prostate cancer

描述(申请人提供)：前列腺癌(PC)是美国男性第二常见的癌症，仅次于皮肤癌。此外，它仅次于肺癌，成为癌症致死的原因之一。美国癌症协会估计，2006年美国将诊断出234,460例新的PC病例，27,350名男性将死于PC。大多数前列腺癌的死亡仍然是由癌细胞扩散到远程组织或器官造成的，最常见的是扩散到骨骼，这些组织或器官对传统疗法具有抵抗力。因此，必须为这一毁灭性疾病开发新的治疗方式。这项第一阶段的申请提出的研究将有助于开发和临床翻译一种新的治疗方案，该方案将传统化疗药物与具有强大抗前列腺癌抗肿瘤活性的抗血管生成剂VMicro statin(VN)相结合。我们最近的研究表明，我们可以生产出一种重组版本的CN(由于重组蛋白包含CN以及其他去整合素中的特征，我们产生的重组蛋白被命名为VMicro statin，VN，由毒蛇和鳄鱼去整合素序列组合而成)，在体外和体内都具有与天然蛋白一样的活性。在这个第一阶段的提案中，我们将证明VN(LVN)的脂质体制剂可以制备成适合临床使用的形式。此外，我们将证明，在前列腺癌小鼠模型中静脉(IV)注射该制剂可有效控制肿瘤生长、血管生成和转移。我们假设：(I)VN可以在细菌表达系统中生产出适合临床试验的水平；(Ii)LVN可以通过一种技术制备，该技术将为临床使用提供足够的材料；以及(Iii)LVN将显示出令人印象深刻的抗癌效果以及适合临床翻译的药理学和毒理学特性。为成功完成这些第一阶段研究确立了以下具体目标和里程碑：具体目标#1：制备足够量的临床应用(里程碑1，0-6个月)的VN(具有完全生物活性并增强对整合素？5？1的亲和力)的改良版本，以及制备具有适当稳定性特征和适合临床应用的量的VN(LVN)的脂质体制剂(里程碑2，0-12个月)。具体目标#2：检查LVN的初始毒理学特性(里程碑3，6-12个月)。具体目的#3：检测VN联合化疗在人前列腺癌(PCa)啮齿动物模型中的疗效。鉴于临床上抗血管生成药物将需要与不同作用机制的化疗药物或抗血管生成药物联合使用，我们将研究VN与用于治疗前列腺癌的化疗药物如多西紫杉醇的联合疗效。在这些研究中，我们将使用活体内的人PCA皮下和原位异种移植模型。作为啮齿动物模型研究的一部分，我们将测试LVN+/-雄激素消融+/-化疗对抗雄激素依赖性前列腺癌的活性。我们将确定联合治疗(里程碑4，9-12个月)是否有增强的抗肿瘤/抗血管生成效果。具体目标#4：在啮齿动物模型中确定LVN是否具有抗PCA骨转移的活性。PCA的一个主要生命终结问题是骨转移的破坏性影响。我们将用发光的PC细胞系建立前列腺癌骨转移的啮齿类动物模型，这将使我们能够确定LVN联合雄激素消融+/-化疗在治疗现有骨转移和预防新的骨损害方面的疗效(里程碑5，6-12个月)。前列腺癌的治疗需要新的方法。血管生成是肿瘤生长和转移的关键步骤。本申请中描述的里程碑将展示LVN单独以及与其他化疗药物联合使用在人前列腺癌异种移植和骨转移啮齿动物模型中的治疗效果。我们期望拟议的研究将确定VN作为一种抗癌药物，可能适合于前列腺癌的进一步临床研究。俗语：前列腺癌是美国男性癌症死亡的第二大原因。我们已经鉴定出一种具有强大抗癌活性的天然蛋白质。在开发更有效的前列腺癌治疗方法的过程中，我们已经产生了一种天然蛋白质的重组变体。在这项提案中，我们将展示重组蛋白具有相当于天然蛋白的活性，并可用于前列腺癌的治疗。我们将检测该蛋白单独以及与当前前列腺癌治疗方法联合使用的抗肿瘤效果，并评估该蛋白的毒理学特性。这些研究将推进这种新型抗癌蛋白的临床潜力。

DESCRIPTION (provided by applicant): Prostate cancer (PC) is the second most common form of cancer in American males, second only to skin cancer. In addition, it trails only lung cancer as a cause of death from cancer. The American Cancer Society estimated that 234,460 new cases of PC would be diagnosed in the United States and 27,350 men would die from PC in 2006. Most deaths from prostate cancer are still caused by spread of the cancer cells to remote tissue or organs, most frequently to the skeleton, which are resistant to conventional therapies. It is imperative, therefore, that new treatment modalities be developed for this devastating disease. This Phase I application proposes studies that will aid in the development of and clinical translation of a novel therapeutic regimen which combines conventional chemotherapeutics with the antiangiogenic agent, vicrostatin (VN), which possesses potent antitumor activity against prostate cancer. Our recent studies have shown that we can produce a recombinant version of CN (since the recombinant protein contains features found both in CN as well as other disintegrins, the recombinant protein we produce has been given the name vicrostatin, VN, a combination of viper and croatalid disintegrin sequences) that is as active as the native protein both in vitro and in vivo. In this Phase I proposal we will demonstrate that a liposomal formulation of VN (LVN) can be prepared in a form suitable for clinical use. Further, we will show that intravenous (IV) delivery of this formulation in a mouse model of prostate cancer produces effective control of tumor growth, angiogenesis and metastasis. We hypothesize that: (i) VN can be produced in a bacterial expression system at levels that will be suitable for clinical trials; (ii) LVN can be prepared by a technology that will provide sufficient material for clinical use; and (iii) LVN will demonstrate impressive anticancer efficacy and pharmacological and toxicological properties suitable for clinical translation. The following specific aims and milestones are established for the successful completion of these Phase I studies: Specific aim #1: Prepare a modified version of VN (that has full biological activity and enhanced affinity for integrin ?5¿1) in sufficient quantity for clinical application (Milestone 1, months 0-6), and prepare a liposomal formulation of VN (LVN) with appropriate stability characteristics and in amounts suitable for clinical application (Milestone 2, months 0-12). Specific Aim #2: Examine initial toxicologic properties of LVN (Milestone 3, months 6-12). Specific Aim #3: Examine efficacy of VN combined with chemotherapy in rodent models of human prostate cancer (PCA). In view of the realization that in the clinic antiangiogenic drugs will need to be used in combination with chemotherapeutic agents or antiangiogenic agents with a different mechanism of action, we will examine effectiveness of the combination of VN with a chemotherapeutic agent used for treatment of PCA, such as docetaxel. For these studies we will employ human PCA subcutaneous and orthotopic xenograft models in vivo. As part of the rodent model studies we will test the activity of LVN +/- androgen ablation +/- chemotherapy against androgen-dependent PCA. We will determine whether there is enhanced antitumor/antiangiogenic efficacy with combination therapy (Milestone 4, months 9-12). Specific Aim #4: Determine if LVN has activity against bone metastases from PCA in rodent models. A major end-of-life issue in PCA is the devastating effect of bone metastases. We will establish rodent models of prostate cancer bone metastases with a luminescent PC cell line which will allow us to determine the efficacy of LVN in combination with androgen ablation+/-chemotherapy in treating existing bone metastases and preventing new bone lesions (Milestone 5, months 6-12). New approaches for the treatment of prostate cancer are needed. Angiogenesis is a critical step for tumor growth and metastasis. The milestones delineated in this application will demonstrate the therapeutic efficacy of LVN alone and in combination with other chemotherapeutic agents in xenograft and bone metastasis rodent models of human prostate cancer. We expect that the proposed studies will identify VN as an anti-cancer agent that may be suitable for further clinical studies in prostate cancer. Lay Language: Prostate cancer is the second leading cause of cancer death of men in the United States. We have identified a natural protein that possesses potent anti- cancer activities. In the development of more effective prostate cancer therapies we have produced a recombinant variant of the natural protein. In this proposal we will show that the recombinant protein has activity equivalent to the natural protein and is amenable to therapeutic use in prostate cancer. We will examine the anti-tumor efficacy of this protein alone and in combination with current prostate cancer therapeutics as well as evaluate the toxicologic properties of the protein. These studies will advance the clinical potential of this novel anticancer protein.