Zou Ying, Fan Guobiao, Wang Xuemin
Skin & Cosmetic Research Department, Shanghai Skin Disease Hospital, Shanghai, China.
Skin & Cosmetic Research Department, Shanghai Skin Disease Hospital, Shanghai, China.
Biochem Biophys Res Commun. 2016 Aug 12;477(1):1-8. doi: 10.1016/j.bbrc.2016.03.020. Epub 2016 Mar 10.
The present study aims to investigate the anti-melanoma activity by an Akt1 specific inhibitor A-674563. We showed that A-674563 was anti-proliferative and cytotoxic when added to human melanoma cells (A375, WM-115 and SK-Mel-2 lines). A-674563 induced caspase-dependent apoptotic death of human melanoma cells, and its cytotoxicity was inhibited with pre-treatment of caspase inhibitors. Further, A-674563 treatment blocked Akt and its downstream S6 Kinase 1 (S6K1) activation in A375 melanoma cells. Significantly, restoring Akt-S6K1 activation via introduction of constitutively-active Akt1 (ca-Akt1) only partially attenuated A-674563's cytotoxicity against A375 cells. Further, A-674563 induced pro-apoptotic ceramide production in A375 cells. Significantly, sphingosine-1-phosphate (S1P) inhibited A-674563-induced ceramide production and subsequent A375 cell apoptosis. On the other hand, co-treatment with the glucosylceramide synthase (GCS) inhibitor PDMP or the cell permeable short-chain ceramide (C6) potentiated A-674563's cytotoxicity against A375 cells. In vivo, A-674563 oral gavage inhibited A375 xenograft growth in severe combined immunodeficiency (scid) mice. Akt inactivation, caspase-3 activation and ceramide production were also observed in A-674563-treated A375 xenografts. Together, these results suggest that A-674563 exerts potent anti-melanoma activity, involving Akt-dependent and Akt-independent mechanisms.
本研究旨在探讨Akt1特异性抑制剂A-674563的抗黑色素瘤活性。我们发现，将A-674563添加到人黑色素瘤细胞（A375、WM-115和SK-Mel-2细胞系）中时，它具有抗增殖和细胞毒性作用。A-674563诱导人黑色素瘤细胞发生caspase依赖性凋亡死亡，且其细胞毒性可被caspase抑制剂预处理所抑制。此外，A-674563处理可阻断A375黑色素瘤细胞中Akt及其下游的S6激酶1（S6K1）的激活。值得注意的是，通过引入组成型激活的Akt1（ca-Akt1）恢复Akt-S6K1激活，仅部分减弱了A-674563对A375细胞的细胞毒性。此外，A-674563诱导A375细胞中促凋亡神经酰胺的产生。值得注意的是，鞘氨醇-1-磷酸（S1P）抑制A-674563诱导的神经酰胺产生及随后的A375细胞凋亡。另一方面，与葡萄糖神经酰胺合酶（GCS）抑制剂PDMP或细胞可渗透的短链神经酰胺（C6）共同处理可增强A-674563对A375细胞的细胞毒性。在体内，A-674563口服灌胃可抑制严重联合免疫缺陷（scid）小鼠中A375异种移植物的生长。在A-674563处理的A375异种移植物中也观察到Akt失活、caspase-3激活和神经酰胺产生。总之，这些结果表明A-674563发挥强大的抗黑色素瘤活性，涉及Akt依赖性和Akt非依赖性机制。
