黃芩素對 B16F10 老鼠黑瘤細胞增生的抑制機轉之研究   全文下載

Studies on the Inhibitory Mechanisms of Baicalein in B16F10 Melanoma Cell Proliferation

在我們的早先研究結果顯示黃芩素通過12-脂加氧?（12-lipoxy-genase）導致超氧自由基和羥基自由基在B16F10老鼠黑瘤細胞中形成；同時發現黃芩素導致了細胞存活能力的減少並且導致細胞凋亡（apoptosis）。目前，黃芩素導致的細胞死亡是否介入12-脂加氧?的抑制或是活性氧化物(reactive oxygen species, ROS)的產生還不清楚。我們運用ROS捕捉劑評估ROS的角色在黃芩素導致的細胞死亡，和使用12-脂加氧?下游產物12-hydroxyeicosatetraenoic acid (12-HETE)抵消黃芩素的12-脂加氧?的抑制作用。ROS捕捉劑對細胞成長分化的作用沒有影響，但是在細胞存活檢測(MTT)試驗中，它們可有效地反轉黃芩素導致的細胞存活能力降低。西方墨點分析顯示ROS捕捉劑對細胞凋亡蛋白質活性caspase-3沒有明顯的作用。在12-脂加氧?方面，12-HETE對細胞成長分化無明顯作用，但是它能有效地反轉黃芩素造成的細胞存活能力降低。 12-HETE對黃芩素造成的活性caspase-3增加表現現象也有抑制作用。同時給予ROS捕捉劑與12-HETE使黃芩素造成的損傷減到最小。在B16F10老鼠黑瘤細胞黃芩素誘發ROS形成所造成的細胞死亡多數歸結于細胞壞死。黃芩素對12-脂加氧?的抑制作用造成的細胞凋亡僅佔小部分。"

Baicalein induces the formation of superoxide and hydroxyl radicals via 12-lipoxygenase (12-LOX) in the B16F10 mouse melanoma cell line; baicalein also causes a reduction in cellular viability and induces cell apoptosis. In this study, we utilized ROS scavengers to evaluate the role of ROS in baicalein-induced cell death and used the 12-LOX downstream product, 12-hydroxyeicosatetraenoic acid (12-HETE), to counterbalance the 12-LOX-inhibitory action of baicalein. ROS scavengers had no effect on cell differentiation, but in the cellular viability (MTT) assay, ROS scavengers effectively reversed cell viability reduction induced by baicalein. A Western blot analysis revealed that the ROS scavengers had no effect on the cell apoptosis protein, active caspase-3. From the aspect of 12-LOX, 12-HETE had no effect on cell differentiation, but it effectively reversed the reduction in cellular viability caused by baicalein in B16F10 cells. 12-HETE also possessed an inhibitory effect on the increase in expression of active caspase-3 caused by baicalein. Combined pretreat-ment with ROS scavengers and 12-HETE minimized the damage caused by baicalein. The majority of cell death occurring in response to baicalein-induced ROS formation in B16F10 mouse melanoma was due to cell necrosis. Cell apoptosis due to 12-LOX suppression by baicalein only accounted for a small portion.