Lin Kai-Wei, Huang A-Mei, Lin Chi-Chen, Chang Chia-Che, Hsu Wei-Chi, Hour Tzyh-Chyuan, Pu Yeong-Shiau, Lin Chun-Nan
Faculty of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
Department of Medicine, Graduate Institute of Biochemistry, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
Eur J Pharmacol. 2014 Oct 5;740:742-51. doi: 10.1016/j.ejphar.2014.05.051. Epub 2014 Jun 14.
Ursolic acid and most of its derivatives are cytotoxic to bladder cancer cells. An ursolic acid derivative, isopropyl 3β-hydroxyurs-12-en-28-oat (UA17), previously reported that it exhibited potent cytotoxicity against bladder cancer cells, NTUB1 cells. In this study, we further investigated the underlying mechanism of UA17 and evaluated its potential clinical use. UA17 may exert the onset of a p53-mediated p38 MAPK activation to up-regulate GADD153. GADD153, in turn, down-regulated Bcl-2 protein to cause mitochondrial membrane potential loss and apoptosis through intracellular ROS generation. In addition, UA17 markedly decreased the levels of cyclins (D1 and E), cyclin-dependent kinases (CDK2 and CDK4), and caused increase of p21 and p27 levels. To assess the suitability of UA17 as a chemotherapeutic agent against NTUB1 cells, its cytotoxic effects have been further evaluated in the combination with cisplatin. The addition of UA17 to cisplatin induces possibly additive cell growth inhibition which correlated to the accumulation of S phase cells and a corresponding decrease in accumulation of G1 phase cells, accompanied an increased accumulation of sub-G1 phase cells. Furthermore, UA17/cisplatin combination exhibited increase of p21, cyclin E, and p-p53 level, and decrease of p27 and cyclin D1 proteins, and slightly diminishing the level of CDK2. P-p38 up-regulation induced by UA17/cisplatin combination through generation of ROS and Bcl-2 down-regulation induced by UA17/cisplatin combination increased cell death. Finally, the antitumorigenic effects of UA17 or UA17/cisplatin combination were further supported by their inhibition on growth of bladder tumor cells in a therapeutic murine MBT-2 bladder tumor model.
熊果酸及其大多数衍生物对膀胱癌细胞具有细胞毒性。一种熊果酸衍生物，3β - 羟基乌苏 - 12 - 烯 - 28 - 酸异丙酯（UA17），先前报道其对膀胱癌细胞NTUB1细胞表现出强大的细胞毒性。在本研究中，我们进一步研究了UA17的潜在机制，并评估了其潜在的临床应用价值。UA17可能通过p53介导的p38丝裂原活化蛋白激酶（MAPK）激活来上调生长停滞和DNA损伤诱导蛋白153（GADD153）。反过来，GADD153下调Bcl - 2蛋白，通过细胞内活性氧（ROS）生成导致线粒体膜电位丧失和细胞凋亡。此外，UA17显著降低细胞周期蛋白（D1和E）、细胞周期蛋白依赖性激酶（CDK2和CDK4）的水平，并导致p21和p27水平升高。为了评估UA17作为针对NTUB1细胞的化疗药物的适用性，其细胞毒性作用已与顺铂联合进行了进一步评估。将UA17添加到顺铂中可能诱导相加性细胞生长抑制，这与S期细胞的积累以及G1期细胞积累的相应减少相关，同时伴有亚G1期细胞积累增加。此外，UA17/顺铂联合用药表现出p21、细胞周期蛋白E和磷酸化p53水平升高，p27和细胞周期蛋白D1蛋白水平降低，以及CDK2水平略有下降。UA17/顺铂联合用药通过ROS生成诱导的磷酸化p38上调以及UA17/顺铂联合用药诱导的Bcl - 2下调增加了细胞死亡。最后，在治疗性小鼠MBT - 2膀胱肿瘤模型中，UA17或UA17/顺铂联合用药对膀胱肿瘤细胞生长的抑制进一步支持了它们的抗肿瘤作用。
