Molecular mechanism of Antrodia cinnamomea sulfated polysaccharide on the suppression of lung cancer cell growth and migration via induction of transforming growth factor β receptor degradation

A sulfated polysaccharide of edible mushroom Antrodia cinnamomea (SPS) has been identified as a novel immunomodulatory agent. We examined the anti-cancer effects of SPS by conducting a series of in vitro studies. We found that SPS inhibits the growth of A549 and LLC1 lung cancer cells via the induction of cell cycle arrest and activation of caspase 3 and PARP. By contrast, we found that a non-sulfated polysaccharide of A. cinnamomea (NSPS) does not inhibit lung cancer cell viability. Moreover, NSPS does not induce changes in cell cycle distribution or activate apoptosis-related molecules in both A549 and LLC1 cells. High expression of transforming growth factor beta (TGF beta) and TGF beta receptors (TGFRs) is correlated with lung tumorigenesis. SPS suppresses TGF beta-induced intracellular signaling events, including phosphorylation of Smad2/3, FAK, Akt, and cell migration. By contrast, non-sulfated polysaccharide (NSPS) does not exhibit the similar biological functions in both A549 and LLC1 cells. Mechanistically, we demonstrated SPS effectively reduces TGFR protein levels via induction of proteasome-dependent degradation pathway. Our study is the first to identify the pivotal role of SPS in the induction of TGFR degradation and activation of Caspase 3 and PARP, which leads to suppress viability and migration of lung cancer cells. (C) 2016 Elsevier B.V. All rights reserved.