Lichen secondary metabolites in Flavocetraria cucullata exhibit anti-cancer effects on human cancer cells through the induction of apoptosis and suppression of tumorigenic potentials
Authors: Kyung Keun Kim
Soonok Oh
Min-Hye Jeong
Jae-Seoun Hur
Sung-Tae Yee
Florin Cri≈üan
Cheol Moon
Ho-Bin Lee
Thanh Thi Nguyen
Hangun Kim
Yi Yang
Jong-Jin Kim
Kwang Youl Lee
Somy Yoon
Journal: PLoS ONE (2014)
Discipline: Multidisciplinary
Keywords: Lichens; cytotoxic activity; cancer cells; molecular mechanisms; F. cucullata
Affiliations: Korean Lichen Research Institute, Sunchon National University, Sunchon, Republic of Korea; Faculty of Natural Science and Technology, Tay Nguyen University, Buon Ma Thuot, Vietnam., Medical Research Center for Gene Regulation, Chonnam National University Medical School, Gwangju, Republic of Korea., Korean Lichen Research Institute, Sunchon National University, Sunchon, Republic of Korea., College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Sunchon, Republic of Korea., Department of Taxonomy and Ecology, Faculty of Biology and Geology, Babes'-Bolyai University, Cluj-Napoca, Romania., College of Pharmacy, Chonnam National University, Gwangju, Korea.

Abstract:  Lichens are symbiotic organisms which produce distinct secondary metabolic products. In the present study, we tested the cytotoxic activity of 17 lichen species against several human cancer cells and further investigated the molecular mechanisms underlying their anti-cancer activity. We found that among 17 lichens species, F. cucullata exhibited the most potent cytotoxicity in several human cancer cells. High performance liquid chromatography analysis revealed that the acetone extract of F. cucullata contains usnic acid, salazinic acid, Squamatic acid, Baeomycesic acid, d-protolichesterinic acid, and lichesterinic acid as subcomponents. MTT assay showed that cancer cell lines were more vulnerable to the cytotoxic effects of the extract than non-cancer cell lines. Furthermore, among the identified subcomponents, usnic acid treatment had a similar cytotoxic effect on cancer cell lines but with lower potency than the extract. At a lethal dose, treatment with the extract or with usnic acid greatly increased the apoptotic cell population and specifically activated the apoptotic signaling pathway; however, using sub-lethal doses, extract and usnic acid treatment decreased cancer cell motility and inhibited in vitro and in vivo tumorigenic potentials. In these cells, we observed significantly reduced levels of epithelial-mesenchymal transition (EMT) markers and phosphor-Akt, while phosphor-c-Jun and phosphor-ERK1/2 levels were only marginally affected. Overall, the anti-cancer activity of the extract is more potent than that of usnic acid alone. Taken together, F. cucullata and its subcomponent, usnic acid together with additional component, exert anti-cancer effects on human cancer cells through the induction of apoptosis and the inhibition of EMT. 

Retracted: No

PubPeer comments:
 Two images in Figure 6D appear to overlap. ***  , 
 Thank you for let me informed about the problem in this publication. Now, the first author has been returned to their home country, and I tried to contact for this issue. I will make response as soon as possible. ,