Naringenin inhibits the growth of Dictyostelium and MDCK‐derived cysts in a TRPP2 (polycystin‐2)‐dependent manner

Abstract

BACKGROUND AND PURPOSE Identifying and characterizing potential new therapeutic agents to target cell proliferation may provide improved treatments for neoplastic disorders such as cancer and polycystic diseases. EXPERIMENTAL APPROACH We used the simple, tractable biomedical model Dictyostelium to investigate the molecular mechanism of naringenin, a dietary flavonoid with antiproliferative and chemopreventive actions in vitro and in animal models of carcinogenesis. We then translated these results to a mammalian kidney model, Madin-Darby canine kidney (MDCK) tubule cells, grown in culture and as cysts in a collagen matrix. KEY RESULTS Naringenin inhibited Dictyostelium growth, but not development. Screening of a library of random gene knockout mutants identified a mutant lacking TRPP2 (polycystin-2) that was resistant to the effect of naringenin on growth and random cell movement. TRPP2 is a divalent transient receptor potential cation channel, where mutations in the protein give rise to type 2 autosomal dominant polycystic kidney disease (ADPKD). Naringenin inhibited MDCK cell growth and inhibited cyst growth. Knockdown of TRPP2 levels by siRNA in this model conferred partial resistance to naringenin such that cysts treated with 3 and 10 μM naringenin were larger following TRPP2 knockdown compared with controls. Naringenin did not affect chloride secretion. CONCLUSIONS AND IMPLICATIONS The action of naringenin on cell growth in the phylogenetically diverse systems of Dictyostelium and mammalian kidney cells, suggests a conserved effect mediated by TRPP2 (polycystin-2). Further studies will investigate naringenin as a potential new therapeutic agent in ADPKD.

Bitter tastant responses in the amoeba Dictyostelium correlate with rat and human taste assays

“…There are many potential mechanisms behind this effect. Dictyostelium is a well-studied model for cell movement (Dang et al, 2013;Artemenko et al, 2014) and has been explored in a range of pharmacological studies for identifying chemical targets (Robery et al, 2013;Waheed et al, 2014;Lockley et al, 2015). Indeed, a large number of studies have identified changes in cell behavior (particularly in movement) caused by deletion of individual proteins (Chattwood et al, 2014;Fets et al, 2014;Wessels et al, 2014).…”

“…An example of this is provided by a recent study investigating novel targets of a standard strong bitter tastant, phenylthiourea (PTU), in Dictyostelium, where the bitter tastant inhibited cell movement (Robery et al, 2013), and a genetic screen identified a PTU-sensitive receptor with homology to a poorly characterized human GABAB protein, where the human protein restored the sensitivity to PTU in Dictyostelium (Robery et al, 2013). Another study, again in Dictyostelium, identified an ion channel (PDK2) to be targeted by a bitter taste-related compound, naringenin (Glendinning, 1994), a flavonoid found in high levels in citrus fruit (Waheed et al, 2014). This study also confirmed the conserved flavonoid-PDK2 interaction in mammalian (kidney) cells and proposed a therapeutic treatment for genetic mutations in the target through naringenin treatment.…”

“…It is at this stage, that Dictyostelium has been extensively utilized to investigate a range of fundamental biological processes such as cell migration and signal transduction, as well as a range of pharmacological studies. These include identifying the molecular targets of flavonoids (Waheed et al, 2014), bipolar disorder treatments (Williams et al, 2002;Williams, 2005) and epilepsy treatments including the MCT ketogenic diet (Xu et al, 2007;Chang et al, 2012). In all these cases, discoveries in Dictyostelium have been successfully translated to humans or other mammals (Xu et al, 2007;Chang et al, 2013Chang et al, , 2014.…”

A Method for Visualizing Fluorescence of Flavonoid Therapeutics in Vivo in the Model Eukaryote Dictyostelium Discoideum

“…For example, such compound specificity was described previously for the activities of plant polyphenols: only a subset of flavonoids affects the transport of the plant hormone auxin, and thus plant development [6,8,9]. The biomedical literature has recently begun to follow suit, with reports of particular polyphenolic secondary metabolites acting via individual protein targets and reaching distinct subcellular compartments [10,11]. There is also limited evidence for some pathways of flavonoid metabolism in humans, namely glucuronidation, o -methylation, and addition of glutathione, depending on where the compounds are absorbed [12].…”

“…Naringenin (4,5,7-trihydroxyflavanone) reduced cyst formation in both animal and in vitro studies of polycystic kidney disease (PKD): indeed, its action via the PKD2 protein was first demonstrated in the model microbe Dictyostelium [11]. Furthermore, naringenin, kaempferol and quercetin (3,3,4,5,7-pentahydroxyflavone) have been reported to inhibit phosphoinositide 3-kinase, nuclear factor B pathway and kinases involved in pro-apoptic signaling in cancer cells [17,18].…”