Planta Med 2014; 80 - P1L33
DOI: 10.1055/s-0034-1394691

A cold methanolic extract of Ganoderma lucidum (Curtis) P. Karst induces autophagy in a gastric cancer cell line

FS Reis 1, 2, 3, RT Lima 1, 4, P Morales 3, ICFR Ferreira 2, MH Vasconcelos 1, 5
  • 1Cancer Drug Resistance Group, IPATIMUP – Institute of Molecular Pathology and Immunology of the University of Porto, Rua Dr. Roberto Frias s/n, 4200 – 465 Porto, Portugal
  • 2Mountain Research Center (CIMO), ESA, Polytechnic Institute of Bragança, Campus de Santa Apolónia, Ap. 1172, 5301 – 855 Bragança, Portugal
  • 3Dpto. Nutrición y Bromatología II, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), Pza Ramón y Cajal, s/n, E-28040 Madrid, Spain
  • 4CEQUIMED-UP- Centre of Medicinal Chemistry of the University of Porto, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira n.° 228, 4050 – 313 Porto, Portugal
  • 5Laboratory of Microbiology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira n.° 228, 4050 – 313 Porto, Portugal

Beneficial effects have been attributed to Ganoderma lucidum including antioxidant, antitumor and antibacterial properties [1 – 3]. Previous work from our group has identified a methanolic extract (prepared at 25 °C) of this mushroom as being a potent modulator of autophagy in a gastric cancer cell line (AGS) [4]. In the present work, the antitumor potential and autophagy modulatory activity of a methanolic extract of G. lucidum, obtained under cold extraction (-20 °C), was further investigated. The chemical characterization of the extract was previously published by some of the present authors [1]. Tumour cell growth screening was carried out in four human tumor cell lines: AGS (gastric adenocarcinoma), MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and HCT-15 (colorectal adenocarcinoma). The effect of the extract was further studied in the most sensitive cells (AGS), particularly regarding effect in autophagy. The presence of autophagossomes was observed following transfection of cells with a mCherry-LC3 expression vector and the levels of some autophagic proteins was analysed by Western Blot. To confirm if the increase in LC3-II levels was a result from autophagy induction or from a decrease in autophagic flux, cells were treated with the extract and with lysossomal protease inhibitors (E-64 d/pepstatin, to prevent formation of the autophagolysosome), and the expression levels of autophagic proteins was analysed. We verified that this extract provided a GI50 of 66.59 µg/mL in the AGS cell line. In addition, treatment with this extract (GI50 concentration) caused an increase in the expression of LC3-II. Additionally, the extract increased the formation of autophagossomes and when cells were treated with the extract together with E-64 d/pepstatin a further increase in the LC3-II levels was verified, indicating that the extract caused an induction of autophagy.

Acknowledgements: FCT (Portugal) and COMPETE/QREN/EU for financial support to CIMO (PEst-OE/AGR/UI0690/2011) and grant to R.T.L. (SFRH/BPD/68787/2010). QREN for the grant to F. S. Reis (NORTE-07 – 0124-FEDER-000023).

Keywords: Ganoderma lucidum, methanolic extract, AGS, growth inhibition, autophagy

References:

[1] Heleno, S.A. et al. (2012) Food Res Int 46: 135 – 140.

[2] Lin, Z.B., Zhang, H.N. (2004) Acta Pharmacol Sin 25: 1387 – 1395.

[3] Heleno, S.A. et al. (2013) Food Chem Toxicol 58: 95 – 100.

[4] Oliveira, M. et al. Food Funct 5: 1389 – 1394.