Design, synthesis and biological evaluation of novel quercetin derivatives as PPAR-γ partial agonists by modulating Epithelial-mesenchymal transition in lung cancer metastasis

Abstract

ABSTRACTEpithelial-to-mesenchymal transition (EMT) is responsible for driving metastasis of multiple cancer types including lung cancer. Peroxisome proliferator-activated receptor (PPAR)-γ, a ligand-activated transcription factor, controls expression of variety of genes involved in EMT, cellular differentiation, fatty acid metabolism, insulin sensitivity and adipogenesis. Several synthetic compounds act as potent full agonist for PPAR-γ. However, owing to their serious adverse effects, restricts their long-term application. Therefore, partial agonist has been greatly in demand which involves reduced and balanced PPAR-γ activity. Our previous study discerned the efficacy of quercetin and its derivatives to attain favourable stabilization with PPAR-γ. Here we extended this work by synthesizing five novel quercetin derivatives (QDs) namely thiosemicarbazone (QUETSC) and hydrazones (QUEINH, QUENH, QUE2FH and QUESH) and analysed their effects in modulating EMT of lung cancer cell lines via PPAR-γ partial activation. QDs-treated A549 cells exhibited cell death strongly in a dose and time dependent manner at nanomolar concentration along with anti-migratory effects compared to NCI-H460 cells. Of the five derivatives we screened, QUETSC, QUE2FH and QUESH exhibited the property of partial activation as compared to the over-expressive level of rosiglitazone (RSG). Consistently, with PPAR-γ partial activation, these QDs also suppressed EMT process by markedly down-regulating the levels of mesenchymal markers (Snail, Slug and Zeb-1) and concomitant up-regulation of epithelial marker (E-cadherin). In the light of these evidences; QUETSC, QUE2FH and QUESH could be used as a novel selective partial PPAR-γ modulators whose pharmacological properties is distinct from RSG and may be exploited as potential therapeutic anti-metastatic agent.