Cell-type specific targeting of curcumin

描述(由申请人提供) 非传统和替代药物正在成为治疗各种疾病的越来越有吸引力的方法。在非传统方法中，使用食品衍生品具有无毒的优势。其中一种饮食成分是姜黄素，它构成了姜黄的黄色色素，姜黄是赋予咖喱黄色的香料。最近的研究表明，姜黄素具有抗炎和抗癌的双重作用。癌胚抗原(CEA)是一种由肿瘤细胞分泌的糖基化蛋白，与人类结直肠癌的肝转移密切相关。CEA与肝脏中的巨噬细胞库普弗细胞结合，诱导细胞因子的表达，如肿瘤坏死因子α(TNF-α)和白介素1β(IL-1β)。这些反过来诱导内皮细胞上黏附分子的表达。据报道，表达糖类配体和黏附分子的肿瘤细胞与肝内皮细胞结合，导致肝转移。由于姜黄素是巨噬细胞中细胞因子合成的有效抑制因子，因此将姜黄素靶向Kupffer细胞以抑制促转移细胞因子的合成将是理想的。然而，姜黄素很难从肠道吸收，因此，口服给药是将姜黄素靶向特定细胞类型的一种低效方式。因此，这项建议的目标是开发一种高效的脂质体给药系统，将姜黄素特异性靶向Kupffer细胞/巨噬细胞。与全身分布相比，脂质体递送系统在靶向Kupffer细胞方面将提供200倍的改进。因此，在第一个目标中，姜黄素脂质体制剂将被设计用于实验动物的体内给药。姜黄素将使用对pH敏感的脂质体输送，这种脂质体旨在破坏内膜的稳定性，因此，在库普弗细胞/巨噬细胞隔离之后，脂质体内容物将被释放到胞浆中。预计脂质体制剂将比口服给药更有效地将姜黄素输送到库普弗细胞至少两个数量级。 在第二个目标中，在成功传递脂质体-姜黄素之后，将测试姜黄素抑制脂多糖(LPS)诱导的细胞因子和前列腺素类物质产生的体内效果。此外，还将确定姜黄素抑制内皮细胞黏附分子、ICAM-1和E-选择素表达(MRNA)的效果。在另一系列实验中，预先注射姜黄素的大鼠肝脏切片和Kupffer细胞将分别暴露于CEA和LPS，以评估姜黄素对TNF-α和IL-1β产生的抑制程度。脂质体-姜黄素成功抑制细胞因子和前列腺素类物质的分泌将极大地增强我们发现治疗癌症和其他炎症性疾病的新的无毒方法的能力。这些研究将为脂质体-姜黄素制剂消除结直肠癌肝转移的体内潜力提供有价值的临床前信息。

DESCRIPTION (provided by applicant) Non-traditional and alternative medicines are becoming increasingly attractive approaches for the treatment of various diseases. Among the non-traditional approaches is the use of food derivatives, which have the advantage of being non-toxic. One such dietary ingredient is curcumin, which constitutes the yellow pigment of turmeric, the spice that gives yellow color to curry. Recent studies show that curcumin has both anti-inflammatory and anti-cancer properties. Carcinoembryonic antigen (CEA), a glycosylated protein secreted by tumor cells, has been implicated in the development of hepatic metastasis of human colorectal cancers. CEA binds to Kupffer cells, the resident macrophages in the liver, inducing the expression of cytokines, such as tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta). These, in turn, induce the expression of adhesion molecules on endothelial cells. Tumor cells expressing carbohydrate ligands to adhesion molecules have been reported to bind to hepatic endothelial cells, resulting in liver metastasis. Since curcumin is a potent inhibitor of cytokine synthesis in macrophages, it would be ideal to target curcumin to Kupffer cells to suppress the synthesis of pro-metastatic cytokines. However, curcumin is poorly absorbed from the gut, and hence, oral delivery is an inefficient way of targeting curcumin to specific cell types. Therefore, it is the objective of this proposal to develop a highly efficient liposome-based delivery system to specifically target curcumin to Kupffer cells/macrophages. A liposomal delivery system would provide a 200-fold improvement in targeting Kupffer cells compared to whole body distribution. Accordingly, in the first objective, curcumin-encapsulated liposomal formulations will be designed for in vivo delivery in experimental animals. Curcumin will be delivered using pH-sensitive liposomes, which are designed to destabilize the endosomal membrane, such that, following sequestration by Kupffer cells/macrophages, the liposomal contents will be released into the cytosol. It is expected that the liposomal formulation will deliver curcumin at least two orders of magnitude more efficiently to Kupffer cells than by oral administration. In the second objective, following a successful delivery of liposomal-curcumin, the in vivo efficacy of curcumin to suppress lipopolysaccharide (LPS)-induced production of cytokines and prostanoids will be tested. Further, the efficacy of curcumin to inhibit LPS-induced expression (mRNA) of adhesion molecules, ICAM-1 and E-selectin in endothelial cells will also be determined. In another series of experiments, liver slices and Kupffer cells from rats pre-injected with curcumin will be exposed to CEA and LPS separately, to assess the extent of inhibition of TNF-alpha and IL-1beta production by curcumin administration. A successful inhibition of cytokine and prostanoid secretions by liposomal-curcumin will greatly enhance our ability to discover new and non-toxic ways to treat cancer and other inflammatory diseases. These studies will provide valuable pre-clinical information on the in vivo potential of the liposomal-curcumin formulation to abrogate liver metastasis of colorectal cancer.