title: GMI, an Immunomodulatory Protein from Ganoderma microsporum, Potentiates Cisplatin-Induced Apoptosis via Autophagy in Lung Cancer Cells.
abstract: Cisplatin-based therapy is common in the treatment of several types of cancers, including lung cancers. In our previous study, GMI, an immunomodulatory protein cloned from Ganoderma microsporum, induced a cytotoxic effect in lung cancer cells via autophagy. The aim of this study is to examine the role of GMI in enhancing cisplatin-mediated cell death. On the basis of MTT assay and Combination Index, GMI and cisplatin cotreatment induced a synergistic cytotoxic effect. GMI and cisplatin-induced apoptosis was determined by sub-G1, nuclear condensation, and annexin-V/propidium iodide analyses. On Western blot, expressions of γH2AX and cleaved forms of PARP, caspase-3, and caspase-7 were induced by combined treatment. Akt/mTOR pathway activity, LC3-II expression, and acidic vesicular organelle development demonstrated that cisplatin does not abolish GMI-mediated autophagy. Cyto-ID Green/hoechst 33342 double staining and time-dependent experiment indicated that GMI and cisplatin-treated A549 cells simultaneously express autophagosomes and apoptotic nuclei. To elucidate the role of autophagy in inducing apoptosis by GMI and cisplatin, chemical inhibitors and LC3 shRNA were used to inhibit autophagy. The results showed that 3-methyladenine decreases, while chloroquine increases GMI and cisplatin cotreatment-induced cleavage of caspase-7 and PARP. LC3 silencing abolished activation of apoptosis in A549 cells. Caspase inhibitors and caspase-7 silencing mitigated GMI and cisplatin-elicited cell viability inhibition and apoptosis. This is the first study to reveal the novel function of GMI in potentiating cisplatin-mediated apoptosis. GMI and cisplatin induce apoptosis via autophagy/caspase-7-dependent and survivin- and ERCC1-independent pathway. GMI may be a potential cisplatin adjuvant against lung cancer.
authors: †Institute of Medicine, Chung Shan Medical University, Taichung 40203, Taiwan.
authors: I-Lun
authors: IL
authors: Hsin
authors: ‡School of Nutrition, Chung Shan Medical University, Taichung 40201, Taiwan.
authors: Chu-Chyn
authors: CC
authors: Ou
authors: †Institute of Medicine, Chung Shan Medical University, Taichung 40203, Taiwan.|§School of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan.|⊥Department of Medical Oncology and Chest Medicine, Chung Shan Medical University Hospital, Taichung 402, Taiwan.
authors: Ming-Fang
authors: MF
authors: Wu
authors: ¶Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung 40201, Taiwan.|#Division of Allergy, Immunology, and Rheumatology, Chung Shan Medical University, Taichung 40201, Taiwan.
authors: Ming-Shiou
authors: MS
authors: Jan
authors: ∥Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 40601, Taiwan.
authors: Yi-Min
authors: YM
authors: Hsiao
authors: §School of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan.|□Division of Chest Medicine, Department of Internal Medicine, Changhua Christian Hospital, Changhua 500, Taiwan.|■Department of Respiratory Care, College of Health Sciences, Chang Jung Christian University, Tainan 71101, Taiwan.
authors: Ching-Hsiung
authors: CH
authors: Lin
authors: †Institute of Medicine, Chung Shan Medical University, Taichung 40203, Taiwan.|§School of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan.|⊥Department of Medical Oncology and Chest Medicine, Chung Shan Medical University Hospital, Taichung 402, Taiwan.
authors: Jiunn-Liang
authors: JL
authors: Ko
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D005656:Fungal Proteins / Q000494:pharmacology*; D032902:Ganoderma / Q000737:chemistry*; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D053148:Caspase 3; D053179:Caspase 7; D002945:Cisplatin
keywords: GMI; apoptosis; autophagy; caspase-7; cisplatin