Carnosic acid modulates Akt/IKK/NF-κB signaling by PP2A and induces intrinsic and extrinsic pathway mediated apoptosis in human prostate carcinoma PC-3 cells
Carnosic acid modulates Akt/IKK/NF-κB signaling by PP2A and induces intrinsic and extrinsic pathway mediated apoptosis in human prostate carcinoma PC-3 cells
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DOI：
10.1007/s10495-012-0715-4
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发表时间：
2012-07-01
期刊：
影响因子：
7.2
通讯作者：
Das, Pijush K.
中科院分区：
文献类型：
--
作者：
Kar, Susanta;Palit, Shreyasi;Das, Pijush K.
本研究探讨了从植物迷迭香（Rosemarinus officinalis）中分离的多酚二萜鼠尾草酸（CA）对雄激素非依赖性人前列腺癌PC-3细胞的作用。CA对PC-3细胞的抗增殖作用呈浓度依赖性和时间依赖性，这是由于流式细胞术、DNA阶梯和TUNEL实验显示的凋亡诱导所致。凋亡与caspase-8、-9、-3和-7的激活、Bax:Bcl-2比值的升高、细胞色素c的释放和凋亡抑制剂（IAP）家族蛋白的表达降低有关。用特定的caspase-8 （Z-IETD-fmk）和caspase-9 （Z-LEHD-fmk）抑制剂预处理后，细胞凋亡减弱，表明参与了内源性和外源性凋亡级联反应。此外，IKK/NF-kappa B通路的抑制导致细胞凋亡，这可以从DNA结合活性降低、p50和p65的核易位以及I kappa B α磷酸化中得到证明。IKK/NF-kappa B的下调与Akt磷酸化及其激酶活性的抑制有关，并伴随丝氨酸/苏氨酸蛋白磷酸酶2A （PP2A）活性的增加。冈田酸和calyculin A对PP2A的药理学抑制可显著逆转CA介导的PC-3细胞凋亡事件，表明CA通过调节Akt/IKK/NF-kappa B通路激活PP2A诱导细胞凋亡。此外，CA通过激活caspase 3、切割PARP、增加Bax:Bcl-2比值和细胞色素c释放等内在途径诱导另一雄激素难愈性前列腺癌DU145细胞凋亡。因此，鼠尾草酸可能具有用于预防和/或治疗前列腺癌的潜力。
This study investigates the efficacy of carnosic acid (CA), a polyphenolic diterpene, isolated from the plant rosemary (Rosemarinus officinalis), on androgen-independent human prostate cancer PC-3 cells. CA induced anti-proliferative effects in PC-3 cells in a concentration- and time-dependent manner, which was due to apoptotic induction as evident from flow-cytometry, DNA laddering and TUNEL assay. Apoptosis was associated with the activation of caspase-8, -9, -3 and -7, increase in Bax:Bcl-2 ratio, release of cytochrome-c and decrease in expression of inhibitor of apoptosis (IAP) family of proteins. Apoptosis was attenuated upon pretreatment with specific inhibitors of caspase-8 (Z-IETD-fmk) and caspase-9 (Z-LEHD-fmk) suggesting the involvement of both intrinsic and extrinsic apoptotic cascades. Further, apoptosis resulted from the inhibition of IKK/NF-kappa B pathway as evident from decreased DNA binding activity, nuclear translocation of p50 and p65 and I kappa B alpha phosphorylation. The down-regulation of IKK/NF-kappa B was associated with inhibition of Akt phosphorylation and its kinase activity with a concomitant increase in the serine/threonine protein phosphatase 2A (PP2A) activity. Pharmacologic inhibition of PP2A by okadaic acid and calyculin A, significantly reversed CA-mediated apoptotic events in PC-3 cells indicating that CA induced apoptosis by activation of PP2A through modulation of Akt/IKK/NF-kappa B pathway. In addition, CA induced apoptosis in another androgen refractory prostate cancer DU145 cells via intrinsic pathway as evidenced from the activation of caspase 3, cleavage of PARP, increase in Bax:Bcl-2 ratio and cytochrome-c release. Carnosic acid, therefore, may have the potential for use in the prevention and/or treatment of prostate cancer.