紫鉚花素誘發乳癌細胞走向細胞凋亡透過活性氧分子及有絲分裂因數活化蛋白質激酶路徑

紫鉚花素是一種從Rhus verniciflua Stokes抽取的多酚類物質，目前研究發現紫鉚花素可以藉由產生過氧化壓力進而促使許多癌細胞死亡，但是紫鉚花素對於乳癌細胞的作用機制尚未完全厘清。在此研究，我們發現紫鉚花素可以抑制乳癌細胞生長為濃度以及時間依賴性。我們亦利用DNA濃縮以及細胞在sub-G1時期的百分比來偵測紫鉚花素促使細胞走向凋亡現象。紫鉚花素可以產生活性氧化物質並且抑制活化態ERK活性以及活化態AKT活性和增加活化態p-38。利用流式細胞儀的分析，可觀察到紫鉚花素同樣可使乳癌細胞產生大量ROS，之後再處理抗氧化劑N-acetyl-cysteine (NAC)不但能降低紫鉚花素所造成ROS的產生並且能減少紫鉚花素對乳癌細胞的毒殺效果。綜合我們的研究顯示紫鉚花素可以抑制乳癌細胞生長並透過活性氧化物質和經由MAPKs路徑和AKT 路徑，促使Bcl-2蛋白的下降，讓Caspase 3切割,接著引發PARP的斷裂，進而引發細胞凋亡。

Butein (3,4,2_,4_-tetrahydroxychalcone), a component of Rhus verniciflua Stokes,is known to induce several cancer cell death through oxidative stress, however, the direct involvement of oxidants in butein-induced breast cancer cell death remain unknown. In this study, we show that butein inhibited the proliferation of human breast cancer cell (MDA-MB-231) in a dose- and time-dependent manner. Treatment with butein also induced apoptosis as evidence by increasing DNA condensation and sub-G1 phase DNA content. Butein induced generation of reactive oxygen species (ROS) and accompanied with decreased the phosphorylation states of ERK and AKt and increased the phosphorylation states of p-38, decreased B-cell lymphoma-2 (Bcl2) expression, and was accompanied by poly(ADP-ribose) polymerase (PARP) cleavage Pretreated with N-acetyl cysteine (NAC) which is a strong antioxidant agent abrogated butein-induced apoptotic effect, decreased ROS level, and recovered the phosaphorylation status of ERK , and reduced Bcl2, which consequently caused the cells to undergo apoptosis. Collectedly, our results revealed that butein induced apoptosis in breast cancer cells via generation of ROS and inhibited the activities of ERK and AKT, which can be reversed by pre-treated with antioxidant agent such as NAC.