Role of Nuclear Factor kappa Beta in Activity of BITC against Pancreatic Cancer

描述（由申请人提供）：胰腺癌是美国癌症相关死亡的第四大原因。它是最具侵袭性的人类恶性肿瘤之一，预后差。来自不同地理位置的流行病学研究表明，增加十字花科蔬菜的消费可以降低患胰腺癌的风险。几项研究已经证实，十字花科蔬菜的癌症预防作用可归因于切或咀嚼这些蔬菜时产生的异硫氰酸酯（ITCs）。已知ITCs在动物模型中对化学诱导的癌症提供重要的保护。然而，尽管有令人信服的流行病学相关性，十字花科蔬菜成分对人类胰腺癌生长的影响尚未确定。我们的初步研究表明，异硫氰酸苄酯（BITC）是ITC家族中一个典型的、研究最多的成员，它通过引起G2/M阻滞和诱导凋亡来抑制人胰腺癌BxPC-3和Capan-2细胞的增殖，而BITC对正常人腺泡和导管细胞的生长影响最小。我们的研究还表明，在胰腺癌中过表达的关键生存分子NF-kappaB、cyclin D1和Bcl-2被bitc治疗显著抑制。基于这些有趣的发现，我们假设人胰腺癌细胞在体外和体内对BITC的生长抑制高度敏感，因为它能够(a)引起细胞周期阻滞，(b)通过抑制NF-kappaB信号通路诱导细胞凋亡。以下是验证我们假设的具体目的：具体目的1将研究口服BITC对裸鼠BxPC-3和Capan-2异种移植物生长的影响。特异性目的2将研究bitc介导的G21M阻滞在两种细胞系中的分子机制。特异性目的3将通过分析NF-kappaB调控因子蛋白激酶C （PKC）和丝裂原活化蛋白激酶（MAPK）通路上下游信号分子的表达和活性，以及这些信号分子之间的串扰，确定bitc在上述细胞中介导NF-kappaB信号通路衰减的机制。特异性目的4将通过遗传（转染）和药理学（抑制剂）方法研究PI3K/PKB信号通路在bitc介导的胰腺癌细胞NFkB抑制中的作用。本应用的实验将为未来的临床研究奠定临床前基础，旨在通过靶向NF-kappaB途径的膳食药物延缓胰腺癌的发生和/或进展。

DESCRIPTION (provided by applicant): Pancreatic cancer is the fourth leading cause of cancer-related death in the United States. It is one of the most aggressive human malignancies with poor prognosis. Epidemiological studies from different geographical locations have suggested that increased consumption of cruciferous vegetables reduces the risk of pancreatic cancer. Several studies have established that cancer preventive effects of cruciferous vegetables are attributable to isothiocyanates (ITCs), which are generated upon cutting or chewing of these vegetables. ITCs are known to offer significant protection against chemically induced cancer in animal models. Despite compelling epidemiological correlation, however, effect of cruciferous vegetable Iconstituents on growth of human pancreatic cancer has not been determined. Our preliminary studies demonstrate that benzyl isothiocyanate (BITC), a prototypical and best studied member of the ITC family, inhibits proliferation of human pancreatic cancer BxPC-3 and Capan-2 cells by causing G2/M arrest and inducing apoptosis, whereas growth of normal human acinar and ductal cells is minimally affected by BITC. Our studies have also demonstrated that the key survival molecules NF-kappaB, cyclin D1 and Bcl-2 that are overexpressed in pancreatic cancer are significantly inhibited by BITCtreatment. Based on these interesting findings, we hypothesize that human pancreatic cancer cells would be highly sensitive to growth inhibition by BITC in vitro and in vivo due to its ability to (a) cause cell cycle arrest, and (b) induce apoptosis via inhibition of NF-kappaB signaling pathway. Following are the specific aims to test our hypothesis: Specific aim 1 will investigate the effects of orally administered BITC on growth of BxPC-3 and Capan-2 xenografts in nude mice. Specific aim 2 will investigate the molecular mechanism(s) of BITC-mediated G21M arrest in both the cell lines. Specific aim 3 will determine the mechanism(s) of BITC-mediated attenuation of NF-kappaB signaling pathway in above cells through analysis of the expression and activity of upstream and downstream signaling molecules of protein kinase C (PKC) and mitogen activated protein kinases (MAPK) pathways, which are the regulators of NF-kappaB, and the cross-talk between these signaling molecules. Specific aim 4 will investigate the involvement of PI3K/PKB signaling pathway in BITC-mediated inhibition of NFkB in pancreatic cancer cells using genetic (transfection) and pharmacological (inhibitors) approaches. The experiments proposed in this application will lay the pre-clinical foundation for future clinical studies directed at a novel strategy to delay the onset and/or progression of pancreatic cancer by dietary agent targeting NF-kappaB pathway.