先前文獻指出松杉靈芝菌絲體裡免疫調節蛋白[Ganoderma microsporum immunoregulatory protein (GMI)],它具有抑制腫瘤細胞轉移的功能。過去有關GMI的研究顯示,GMI的效用與腫瘤細胞的侵襲與轉移相關。然而GMI對乳癌抑制其增生或是細胞凋亡啟動的機制尚未明確。因此,本研究目的將探討靈芝免疫調節蛋白對乳癌細胞之機轉。從細胞存活試驗證實GMI可降低乳癌細胞株存活率。以GMI處理乳癌細胞株Hs578T,藉由細胞流式儀(Flow cytometry)分析其細胞週期停留在sub-G1期的情況。再利用西方墨點法(Western blotting assay)及定量反轉錄聚合酶鏈鎖反應(RT-PCR)分析,實驗結果顯示GMI在4小時中,能上調細胞Fas外在的凋亡路徑之相關蛋白表現,並會誘發其內生性的免疫發炎白細胞介素IL-1β與IL-6基因表現,反之Fas基因表現量下降。進一步我們轉殖入IL-6 短片段干擾核糖核酸(Small interfering RNA)後,再同時處理GMI,發現對乳癌細胞經由 Fas所誘導凋亡路徑相關蛋白則有明顯的增加且延長GMI的作用時間。總結,當在抑制IL-6活性時,則會增強GMI對乳癌細胞株Hs578T的凋亡作用。
It has been reported that Ganoderma microsporum immunoregulatory protein (GMI) has an inhibiting effect on tumer cell worsen, inducing invasiveness and migration, in a variety of cancers. However, the effect of GMI on apoptotic induction in breast cancer cells remains unclear. To this aim, we investigated the apoptotic mechanisms of GMI in breast cancer cells, Hs578T and MDA-MB-231 cells lines. We found GMI can reduce cells viability by using MTT assay, showing that after treated with GMI for 4hrs can induce programmed cell death in breast cancer cells. Moreover, GMI induced cell endogenous cytokines IL-1β and IL-6 expression in Hs578T cells, that was associated with inversely expressed of Fas in GMI-treated Hs578T cell line by quantitated using qRT-PCR technique. We identify that the expression of Fas and subseguent apoptotic induced by GMI, could be extended to 8hrs by inhibiting IL-6 production. In conclusion, GMI enhance of Fas apoptotic signaling pathway blocks the activity of IL-6 in Hs578T.