College of Pharmacy and Medical Research Center, Chungbuk National University, Cheongju, South Korea.
Cell Prolif. 2011 Aug;44(4):320-9. doi: 10.1111/j.1365-2184.2011.00761.x. Epub 2011 Jun 6.
Melanoma is the most aggressive form of skin cancer, and it resists chemotherapy. Candidate drugs for effective anti-cancer treatment have been sought from natural resources. Here, we have investigated anti-proliferative activity of myriocin, serine palmitoyltransferase inhibitor, in the de novo sphingolipid pathway, and its mechanism in B16F10 melanoma cells.
We assessed cell population growth by measuring cell numbers, DNA synthesis, cell cycle progression, and expression of cell cycle regulatory proteins. Ceramide, sphingomyelin, sphingosine and sphingosine-1-phosphate levels were analysed by HPLC.
Myriocin inhibited proliferation of melanoma cells and induced cell cycle arrest in the G(2) /M phase. Expressions of cdc25C, cyclin B1 and cdc2 were decreased in the cells after exposure to myriocin, while expression of p53 and p21(waf1/cip1) was increased. Levels of ceramide, sphingomyelin, sphingosine and sphingosine-1-phosphate in myriocin-treated cells after 24 h were reduced by approximately 86%, 57%, 75% and 38%, respectively, compared to levels in control cells.
Our results suggest that inhibition of sphingolipid synthesis by myriocin in melanoma cells may inhibit expression of cdc25C or activate expression of p53 and p21(waf1/cip1) , followed by inhibition of cyclin B1 and cdc2, resulting in G(2) /M arrest of the cell cycle and cell population growth inhibition. Thus, modulation of sphingolipid metabolism by myriocin may be a potential target of mechanism-based therapy for this type of skin cancer.
黑色素瘤是最具侵袭性的皮肤癌，且对化疗有抗性。人们一直在从天然资源中寻找有效的抗癌治疗候选药物。在此，我们研究了从头合成的神经酰胺途径中的丝氨酸棕榈酰转移酶抑制剂——麦角甾醇过氧化物（myriocin）的抗增殖活性及其在 B16F10 黑色素瘤细胞中的作用机制。
我们通过测量细胞数量、DNA 合成、细胞周期进程和细胞周期调控蛋白的表达来评估细胞群体的生长情况。采用 HPLC 分析神经酰胺、神经鞘氨醇、鞘氨醇和 1-磷酸鞘氨醇的水平。
麦角甾醇过氧化物抑制黑色素瘤细胞的增殖，并诱导细胞周期在 G2/M 期停滞。麦角甾醇过氧化物处理后的细胞中 cdc25C、cyclin B1 和 cdc2 的表达减少，而 p53 和 p21(waf1/cip1) 的表达增加。与对照组细胞相比，麦角甾醇过氧化物处理 24 小时后，细胞中神经酰胺、神经鞘氨醇、鞘氨醇和 1-磷酸鞘氨醇的水平分别降低了约 86%、57%、75%和 38%。
我们的研究结果表明，麦角甾醇过氧化物在黑色素瘤细胞中抑制神经鞘脂合成可能通过抑制 cdc25C 的表达或激活 p53 和 p21(waf1/cip1) 的表达，进而抑制 cyclin B1 和 cdc2 的表达，导致细胞周期 G2/M 期阻滞和细胞群体生长抑制。因此，麦角甾醇过氧化物对神经鞘脂代谢的调节可能是针对这种皮肤癌的基于机制的治疗的潜在靶点。
