Cell-type specific targting of curcumin

描述（由申请人提供） 非传统药物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。非传统方法之一是使用食物衍生物，其优点是无毒。其中一种膳食成分是姜黄素，它构成了姜黄的黄色色素，姜黄是一种使咖喱呈黄色的香料。最近的研究表明，姜黄素具有抗炎和抗癌特性。癌胚抗原（CEA）是一种由肿瘤细胞分泌的糖基化蛋白，与人类结直肠癌肝转移的发展有关。CEA结合枯否细胞，肝脏中的常驻巨噬细胞，诱导细胞因子的表达，如肿瘤坏死因子α（TNF-α）和白细胞介素-1 β（IL-1 β）。这些反过来又诱导内皮细胞上粘附分子的表达。已经报道了表达粘附分子的碳水化合物配体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剂，理想的是将姜黄素靶向库普弗细胞以抑制促转移细胞因子的合成。然而，姜黄素从肠道吸收很差，因此，口服给药是将姜黄素靶向特定细胞类型的低效方式。因此，本提案的目的是开发一种高效的基于脂质体的递送系统，以特异性地将姜黄素靶向库普弗细胞/巨噬细胞。与全身分布相比，脂质体递送系统在靶向枯否细胞方面将提供200倍的改善。因此，在第一个目标中，将设计姜黄素包封的脂质体制剂用于在实验动物中的体内递送。姜黄素将使用pH敏感性脂质体递送，所述脂质体被设计成使内体膜不稳定，使得在被枯否细胞/巨噬细胞隔离后，脂质体内容物将释放到胞质溶胶中。预期脂质体制剂将比口服给药更有效地将姜黄素递送至枯否细胞至少两个数量级。 在第二个目标中，在成功递送脂质体-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产生的体内功效。此外，还将测定姜黄素抑制内皮细胞中LPS诱导的粘附分子ICAM-1和E-选择素表达（mRNA）的功效。在另一系列实验中，将来自预先注射姜黄素的大鼠的肝切片和枯否细胞分别暴露于CEA和LPS，以评估姜黄素给药对TNF-α和IL-1 β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分泌将大大提高我们发现新的无毒方法治疗癌症和其他炎症性疾病的能力。这些研究将提供关于脂质体-姜黄素制剂消除结肠直肠癌肝转移的体内潜力的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.