GMI, an immunomodulatory protein fromGanoderma microsporum, induces autophagy in non-small cell lung cancer cells

Abstract

Autophagy is a self-digestive process that degrades the cytoplasmic constituents. Immunomodulatory protein, one major bioactive component of Ganoderma, has antitumor activity. In this study, recombinant fungal immunomodulatory protein, GMI, was cloned from Ganoderma microsporum and purified. We demonstrated that GMI induces lung cancer cell death by activating autophagy, but does not induce apoptotic cell death. On western blot, GMI increased LC3 conversion and decreased p53 expression in a time- and concentration-dependent manner. Cytoplasmic calcium chelator BAPTA-AM was used to prove that GMI promotes autophagy via a calcium-mediated signaling pathway. 3-methyladenine (3-MA), an autophagy inhibitor, enhanced the cytotoxicity of GMI on cell viability assay. Using VZV-G pseudotyped lentivirus-shRNA system for autophagy-related genes silencing, the capabilities of GMI to reduce cell viability and colony formation were abolished in autophagy-defective cells. Furthermore, GMI did not stimulate apoptosis after blocking of autophagy by 3-MA or shRNA knockdown system. In xenograft studies, oral administration of GMI inhibited the tumor growth and induced autophagy significantly in nude mice that had received a subcutaneous injection of A549 cells. This is the first study to reveal the novel function of GMI in activating autophagy. GMI may be a potential chemopreventive agent against non-small cell lung cancer.

Proteome Exploration to Provide a Resource for the Investigation of Ganoderma lucidum

“…The examples include Fip-vvo from Volvariella volvacea [43], GMI from Ganoderma microsporum [44, 45], IPAF from Anoectochilus formosanus [46], AAL and AAL-2 from Agrocybe aegerita [47, 48], and immunomodulatory protein LZ-8 from G . lucidum [49, 50].…”

Thymoquinone Induces Cell Death in Human Squamous Carcinoma Cells via Caspase Activation-Dependent Apoptosis and LC3-II Activation-Dependent Autophagy

“…The cells were seeded onto 35 mm µ-Dish (ibidi, Germany). After overnight culture, cells were transfection with 3 µg GFP-LC3 expressing plasmid in each plate using PolyJet™ reagent (SignaGen Laboratories, Gaithersburg, MD) and incubated for 24 h. The medium was removed and fresh medium containing TQ with either with or without bafilomycin-A1 (Baf A1) was added to the plate for 24 h. At the end of treatment, cells were investigated by the EVOS FL (AMG Micro, Bothell, WA) microscope at 40× magnification [21].…”

“…RNAi reagents were obtained from the National RNAi Core Facility located at the Institute of Molecular Biology/Genomic Research Center in Academia Sinica; this study was supported by the National Research Program for Genomic Medicine Grants of the National Science Council [21].…”

Antitumor effects and mechanisms of Ganoderma extracts and spores oil

“…By detecting the immunity indexes of mice bearing S180 or H22 cells, Ganoderma extracts were concluded to have a certain effect on improving immune function, while Ganoderma spores oil had no significant effect on the spleen or thymus indexes of mice. One of the main components of Ganoderma extract is a polysaccharide that has been reported as immune function enhancer (12)(13)(14)(15). As there were few polysaccharides (water-soluble substances) in the Ganoderma spores oil, the spores oil exhibited no evident effect on immunity.…”

“…Numerous previous studies examined the immunomodulatory activities of Ganoderma (12,13). By detecting the immunity indexes of mice bearing S180 or H22 cells, Ganoderma extracts were concluded to have a certain effect on improving immune function, while Ganoderma spores oil had no significant effect on the spleen or thymus indexes of mice.…”