細胞凋亡、細胞壞死與細胞自體吞噬是三種主要的程序性細胞死亡方式。細胞自體吞噬是一種細胞自我消化細胞質內物質的過程。免疫調節蛋白是靈芝的有效成分之一，已知具有抗癌的功效。重組靈芝免疫調節蛋白GMI是由小孢子靈芝中所選殖並純化而得。於先前研究中，我們發現GMI誘發細胞自噬型死亡毒殺肺癌細胞。在本研究中，我們將觀察結合GMI與Cisplatin共同處理在毒殺肺癌細胞上的作用。適用流式細胞儀分析，GMI與Cisplatin共同處理誘發A549與 CaLu-1細胞發生sub-G1期累積。GMI與Cisplatin共同處理刺激具核濃縮現象的肺癌細胞比例上升。GMI與Cisplatin共同處理顯著增加γH2AX表現與切割態的Caspase-3，Caspase-7與PARP。透過分析Akt/Mtor訊息路徑，LC3-II與酸性囊狀胞器表現量，證實Cisplatin並不破壞GMI誘發細胞自噬的能力。這些結果證實，GMI增強cisplatin觸發細胞凋亡的能力。本研究提供靈芝免疫調節蛋白抗癌的新機制，證實GMI有潛力成為對抗非小細胞肺癌的cisplatin佐劑。
Apoptosis, necrosis, and autophagy are three major types of programmed cel death. Autophagy is a self-digestive process that degrades the cytoplasmic constituents. Immunomodulatory protein, one major bioactive component of Ganoderma, has anti-tumor activity. Recombinant fungal immunomodulatory protein, GMI, was cloned from Ganoderma microsporum and purified. In our previous study, GMI induced autophagic cell death in lung cancer cells. In this study, we investigate the effect of combination treatment with GMI and cisplatin on cytotoxicity in lung cancer cells. Using flow cytometry, GMI and cisplatin cotreatment induced sub-G1 phase accumulation in A549 and CaLu-1 cells. GMI and cisplatin enhanced frequency of apoptotic nuclei in both lung cancer cell lines. Combined treatment markedly enhanced the expressions of γH2AX and the cleaved forms of caspase-3, caspase-7 and PARP. Akt/mTOR pathway activity, LC3-II expression, and acidic vesicular organelle development demonstrated that cisplatin does not abolish GMI-mediated autophagy. These results suggested that GMI enhanced cisplatin-induced apoptosis. GMI may be a potential cisplatin adjuvant against lung cancer.
