Flavonoids kaempferol and quercetin are nuclear receptor 4A1 (NR4A1, Nur77) ligands and inhibit rhabdomyosarcoma cell and tumor growth

Abstract

Background Flavonoids exhibit both chemopreventive and chemotherapeutic activity for multiple tumor types, however, their mechanisms of action are not well defined. Based on some of their functional and gene modifying activities as anticancer agents, we hypothesized that kaempferol and quercetin were nuclear receptor 4A1 (NR4A1, Nur77) ligands and confirmed that both compounds directly bound NR4A1 with KD values of 3.1 and 0.93 μM, respectively. Methods The activities of kaempferol and quercetin were determined in direct binding to NR4A1 protein and in NR4A1-dependent transactivation assays in Rh30 and Rh41 rhabdomyosarcoma (RMS) cells. Flavonoid-dependent effects as inhibitors of cell growth, survival and invasion were determined in XTT and Boyden chamber assays respectively and changes in protein levels were determined by western blots. Tumor growth inhibition studies were carried out in athymic nude mice bearing Rh30 cells as xenografts. Results Kaempferol and quercetin bind NR4A1 protein and inhibit NR4A1-dependent transactivation in RMS cells. NR4A1 also regulates RMS cell growth, survival, mTOR signaling and invasion. The pro-oncogenic PAX3-FOXO1 and G9a genes are also regulated by NR4A1 and, these pathways and genes are all inhibited by kaempferol and quercetin. Moreover, at a dose of 50 mg/kg/d kaempferol and quercetin inhibited tumor growth in an athymic nude mouse xenograft model bearing Rh30 cells. Conclusion These results demonstrate the clinical potential for repurposing kaempferol and quercetin for clinical applications as precision medicine for treating RMS patients that express NR4A1 in order to increase the efficacy and decrease dosages of currently used cytotoxic drugs.

In Vitro Evaluation of Kaempferol-Loaded Hydrogel as pH-Sensitive Drug Delivery Systems

“…Dongmei Pan et al [ 45 ] studied that KAE inhibits migration and invasion of fibroblast-like synovial cells in rheumatoid arthritis by blocking MAPK pathway activation. KAE has chemopreventive and chemotherapeutic activity against a variety of tumors, and a recent study reported that KAE is a nuclear receptor 4A1 (NR4A1, Nur77) ligand that inhibits rhabdomyosarcoma cells and tumor growth [ 46 ]. Tawoo Kim et al found that KAE induced autophagy death of gastric cancer cells through IRE1-JNK-CHOP signaling pathway [ 47 ].…”

Soluble Free, Esterified and Insoluble-Bound Phenolic Antioxidants from Chickpeas Prevent Cytotoxicity in Human Hepatoma HuH-7 Cells Induced by Peroxyl Radicals

“…It has been associated with the improvement in different conditions or diseases such as post-menopausal bone loss [ 45 ], obesity [ 46 ], diabetes [ 47 ], and cancer [ 48 ]. Rutin is another antioxidant compound with various functions at the system levels such as nervous, gastrointestinal, cardiovascular, respiratory, and immune [ 49 ], and is thus considered a potential pharmacological substance. According to Gong et al [ 50 ], the mechanisms of action of isorhamnetin are explained by their anti-inflammation, and antioxidation properties.…”

A Chalcone Synthase-Like Bacterial Protein Catalyzes Heterocyclic C-Ring Cleavage of Naringenin to Alter Bioactivity Against Nuclear Receptors in Colonic Epithelial Cells

“…Binding affinities of naringenin and 34HPPA for NR4A1 and NR4A2 were assayed based on quenching of tryptophan fluorescence as previously described (Shrestha et al ., 2021). The ligand binding domains (LBD) of NR4A1 and NR4A2 were incubated at a fixed concentration (0.5 μM) in PBS with different concentrations of naringenin and 34HPPA.…”

“…There is increasing evidence that the nuclear receptor 4A subfamily, in addition to the AhR, could also play a role in mediating the biological activities of flavonoids. Recent in vitro studies have demonstrated that kaempferol and quercetin can bind the ligand binding domain (LBD) of NR4A1 to inhibit pro-oncogenic NR4A1-regulated pathways (Shrestha et al, 2021). We investigated if naringenin or its gut bacterial metabolites can also bind nuclear receptor 4A LBDs.…”