Design, Synthesis, and Mechanistic Investigations of Bile Acid-Tamoxifen Conjugates for Breast Cancer Therapy
Design, Synthesis, and Mechanistic Investigations of Bile Acid-Tamoxifen Conjugates for Breast Cancer Therapy
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DOI：
10.1021/bc300664k
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发表时间：
2013-09-01
影响因子：
4.7
通讯作者：
Bajaj, Avinash
中科院分区：
文献类型：
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作者：
Sreekanth, Vedagopuram;Bansal, Sandhya;Bajaj, Avinash
我们使用三种胆汁酸石胆酸（LCA）、脱氧胆酸（DCA）和胆酸（CA）合成了两个系列的胆汁酸他莫昔芬缀合物。这些胆汁酸-他莫昔芬缀合物具有1、2和3个他莫昔芬分子，其连接至胆汁酸的羟基，在胆汁酸的尾部区域具有游离酸和胺官能团。这些胆汁酸-他莫昔芬缀合物的体外抗癌活性表明，与母体药物他莫昔芬和其他基于酸和胺头基的胆汁酸-他莫昔芬缀合物相比，基于游离胺头基的胆酸-他莫昔芬缀合物(CA-Tam(3)-Am)是最有效的抗癌缀合物。带有三个他莫昔芬分子的胆酸-他莫昔芬缀合物 (CA-Tam(3)-Am) 在雌激素受体 +ve 和雌激素受体 -ve 乳腺癌细胞系中显示出增强的抗癌活性。 CA-Tam(3)-Am 增强的抗癌活性是由于更有利的不可逆静电相互作用，随后这些缀合物插入膜脂的疏水核心，导致膜流动性增加。基于膜联蛋白-FITC 的 FACS 分析显示细胞发生凋亡，细胞周期分析显示细胞停滞在亚 G(0) 期。 ROS 测定显示，无论细胞系的 ER 状态如何，都会产生大量 ROS，表明摄取缀合物后线粒体膜流动性发生变化，进一步导致细胞色素 c 的释放，细胞色素 c 是 ROS 的直接和间接调节剂。使用PCR和Western分析进行的细胞凋亡机制研究表明，ER +ve MCF-7细胞中通过内在和外在途径发生细胞凋亡，而ER -ve细胞中仅通过内在途径发生细胞凋亡。 4T1 肿瘤模型的体内研究表明 CA-Tam(3)-Am 比他莫昔芬更有效。这些研究表明，胆汁酸为高载药量提供了新的支架，并且其抗癌活性强烈依赖于脂质-药物缀合物的电荷和疏水性。
We have synthesized two series of bile acid tamoxifen conjugates using three bile acids lithocholic acid (LCA), deoxycholic acid (DCA), and cholic acid (CA). These bile acid-tamoxifen conjugates possess 1, 2, and 3 tamoxifen molecules attached to hydroxyl groups of bile acids having free acid and amine functionalities at the tail region of bile acids. The in vitro anticancer activities of these bile acid-tamoxifen conjugates show that the free amine headgroup based cholic acid-tamoxifen conjugate (CA-Tam(3)-Am) is the most potent anticancer conjugate as compared to the parent drug tamoxifen and other acid and amine headgroup based bile acid-tamoxifen conjugates. The cholic acid-tamoxifen conjugate (CA-Tam(3)-Am) bearing three tamoxifen molecules shows enhanced anticancer activities in both estrogen receptor +ve and estrogen receptor -ve breast cancer cell lines. The enhanced anticancer activity of CA-Tam(3)-Am is due to more favorable irreversible electrostatic interactions followed by intercalation of these conjugates in hydrophobic core of membrane lipids causing increase in membrane fluidity. Annexin-FITC based FACS analysis showed that cells undergo apoptosis, and cell cycle analysis showed the arrest of cells in sub G(0) phase. ROS assays showed a high amount of generation of ROS independent of ER status of the cell line indicating changes in mitochondrial membrane fluidity upon the uptake of the conjugate that further leads to the release of cytochrome c, a direct and indirect regulator of ROS. The mechanistic studies for apoptosis using PCR and western analysis showed apoptotsis by intrinsic and extrinsic pathways in ER +ve MCF-7 cells and by only an intrinsic pathway in ER -ve cells. In vivo studies in the 4T1 tumor model showed that CA-Tam(3)-Am is more potent than tamoxifen. These studies showed that bile acids provide a new scaffold for high drug loading and that their anticancer activities strongly depend on charge and hydrophobicity of lipid-drug conjugates.