Tanshinones for prevention of bladder cancer progression

描述(申请人提供)：这项探索性的建议是评估一种新的生物活性成分丹参酮I(T1)在预防膀胱癌进展方面的有效性，并为了解T1的作用机制提供必要的初步证据。膀胱癌是美国第五种最常见的恶性肿瘤。随着膀胱癌发生的病因不明，以及膀胱癌患者在治疗后面临转移和局部复发的威胁，迫切需要更多的努力来确定有效的干预或化学预防策略来防止膀胱癌的进展。因此，寻找预防或延缓膀胱癌进展和转移的有效、安全的策略仍然是膀胱癌研究的重中之重。为了鉴定丹参中的生物活性成分，我们发现丹参中的丹参酮，特别是丹参酮I(T1)，在体外通过下调Aurora A的表达而部分通过诱导细胞凋亡来抑制膀胱癌细胞的生长。T1在体外和体内均显示出明显的抑制血管生成的活性。此外，T1在体外和体内的毒副作用都要小得多。基因功能分析显示，siRNA敲除Aurora A显著抑制肿瘤细胞的生长和诱导细胞凋亡，Aurora A功能的丧失使T1诱导细胞凋亡和抑制细胞生长的活性基本消失。这些有希望的初步结果支持这样的假设，即T1可能通过诱导膀胱癌细胞凋亡和抑制血管生成而作为一种有效而安全的化学预防药物来阻止膀胱癌的进展，而Aurora A可能是T1作用的功能靶点。由于一定水平的T1及其代谢产物通过尿路排泄并与膀胱粘膜直接接触，T1在体内的膀胱癌干预中可能比通过血液循环和尿路暴露发挥抗膀胱癌活性的体外系统具有更强的活性，应用原位膀胱癌模型是进行T1对膀胱癌进展的相关评价的前提。为了验证这一假说，特定目的1是确定T1在高分化/低转移和低分化/高转移膀胱肿瘤模型中对进展的影响；特定目的2是确定与T1在体内的疗效相关的细胞和分子生物标志物；特定目的3是进一步确定Aurora A下调是否在功能上与T1在诱导膀胱癌细胞凋亡和抑制血管生成方面的活性有关。这项建议将确定一种高效、安全的预防膀胱癌进展的化学预防药物，其结果可能导致未来的临床研究将T1开发为膀胱癌的化学预防和/或治疗药物。本研究的结果也将为RO1的应用提供支持证据。 公共卫生相关性：本项目的目标是获得实验证据，证明新型药物丹参酮I(T1)在原位膀胱癌动物模型中抑制膀胱癌生长和进展的有效效果，并确定T1诱导细胞凋亡和抑制血管生成的机制之一是否通过下调Aurora A来实现。本研究的结果将为未来使用这种新型化学预防药物有效预防膀胱癌进展的临床研究提供必要的临床前证据和机制见解，因此拟议的研究将对公众健康产生重大影响。

DESCRIPTION (provided by applicant): This exploratory proposal is to evaluate the efficacy of a novel bioactive component tanshinone I (T1) on preventing bladder cancer progression and to generate essential preliminary evidence to understand the mechanisms of T1 actions. Bladder cancer is the fifth most commonly diagnosed malignancy in the United States. With the unknown etiological factors for bladder carcinogenesis and the fact that bladder cancer patients are facing both threat of metastases and uncontrolled local recurrence after treatment, additional efforts to define effective intervention or chemoprevention strategies against bladder cancer progression are urgently needed. Therefore, the searching for efficacious and safe strategies to prevent or delay the progression and metastasis of bladder cancer remains the top priority in bladder cancer research. In an effort to identify the bioactive components, we found that tanshinones from a Chinese herb Danshen, especially tanshinone I (T1), had potent activities in inhibiting the growth of bladder cancer cells in part via induction of apoptosis in vitro associated with downregulation of Aurora A expression. T1 also showed potent activities in inhibiting angiogenesis in both in vitro and in vivo. Furthermore, T1 showed much less toxicity and side effect in vitro and in vivo. Gene function assays showed that knockdown of Aurora A by siRNA significantly reduced the growth and induced apoptosis of cancer cells, and the T1 activities in inducing apoptosis and inhibiting cell growth were largely eliminated by the loss of Aurora A function. These promising preliminary results support the hypotheses that T1 may serve as an efficacious and safe chemopreventive agent against bladder cancer progression by both inducing bladder cancer cell apoptosis and inhibiting angiogenesis, and that Aurora A may be a functional target for T1 action. Since certain levels of T1 and its metabolites are excreted through the urinary tract and are in direct contact with mucosa of the bladder, T1 may have more potent activity in bladder cancer intervention in the in vivo system than that evaluated in vitro by exerting its anti-bladder cancer activities via both blood circulation and urinary exposure, and application of orthotopic bladder tumor model is a prerequisite for relevant evaluation of T1 on bladder cancer progression. To test the hypothesis, specific aim 1 is to determine the effect of T1 on progression of both well-differentiated/low metastatic and poorly differentiated/highly metastatic human bladder tumors in orthotopic bladder tumor models; Specific aim 2 is determine the cellular and molecular biomarkers that are associated with the efficacy of T1 in vivo; Specific aim 3 is to proposed to further determine if downregulation of Aurora A is functionally responsible for the T1 activities in inducing apoptosis of bladder cancer cells and inhibiting angiogenesis. This proposal will define a highly efficacious and safe chemopreventive agent against bladder cancer progression, and the results may result in future clinical investigations to develop T1 as a chemopreventive and/or therapeutic agent for bladder cancer. The results derived from this research will also provide supporting evidence for the RO1 application. PUBLIC HEALTH RELEVANCE: The goals of this proposed project are to gain experimental evidence to demonstrate the potent efficacy of a novel agent, tanshinones I (T1) in inhibiting the growth and progression of bladder cancer in orthotopic bladder tumor animal models, and to determine if one of the mechanisms by which T1 induces apoptosis and inhibits angiogenesis is by downregulation of Aurora A. The results derived from the proposed studies will provide essential preclinical evidence and mechanistic insights to support the future clinical investigation using this novel chemopreventive agent for effective prevention of bladder cancer progression, thus the proposed research will have significant impacts on public health.