Low concentration of formononetin promotes proliferation of estrogen receptor-positive cells through an ERα-miR-375-PTEN-ERK1/2-bcl-2 pathway

Formononetin, a Beer Polyphenol with Catabolic Effects on Chondrocytes

Beer consumption has been identified as a risk factor for osteoarthritis (OA), a rheumatic disease characterised by cartilage degradation, joint inflammation, and eventual joint failure. One of the main isoflavonoids in beer is formononetin (FNT), an estrogenic compound also found in multiple plants and herbs. In this study, we aimed to investigate the effect of FNT on chondrocyte viability, inflammation, and metabolism. Cells were treated with FNT with or without IL-1β for 48 h and during 7 days of differentiation. Cell viability was determined via MTT assay. Nitrite accumulation was determined by Griess reaction. The expression of genes involved in inflammation and metabolism was determined by RT-PCR. The results revealed that a low concentration of FNT had no deleterious effect on cell viability and decreased the expression of inflammation-related genes. However, our results suggest that FNT overexposure negatively impacts on chondrocytes by promoting catabolic responses. Finally, these effects were not mediated by estrogen receptors (ERs) or aryl hydrocarbon receptor (AhR). In conclusion, factors that favour FNT accumulation, such as long exposure times or metabolic disorders, can promote chondrocyte catabolism. These data may partially explain why beer consumption increases the risk of OA.

Estrogenic flavonoids and their molecular mechanisms of action

Flavonoids are a major group of phytoestrogens associated with physiological effects, and ecological and social impacts. Although the estrogenic activity of flavonoids was reported by researchers in the fields of medical, environmental and food studies, their molecular mechanisms of action have not been comprehensively reviewed. The estrogenic activity of the respective classes of flavonoids, anthocyanidins/anthocyanins, 2-arylbenzofurans/3-arylcoumarins/α-methyldeoxybenzoins, aurones/chalcones/dihydrochalcones, coumaronochromones, coumestans, flavans/flavan-3-ols/flavan-4-ols, flavanones/dihydroflavonols, flavones/flavonols, homoisoflavonoids, isoflavans, isoflavanones, isoflavenes, isoflavones, neoflavonoids, oligoflavonoids, pterocarpans/pterocarpenes, and rotenone/rotenoids, was summarized through a comprehensive literature search, and their structure-activity relationship, biological activities, signaling pathways, and applications were discussed. Although the respective classes of flavonoids contained at least one chemical mimicking estrogen, the mechanisms varied, such as those with estrogenic, anti-estrogenic, non-estrogenic, and biphasic activities, and additional activities through crosstalk/bypassing, which exert biological activities through cell signaling pathways. Such mechanistic variations of estrogen action are not limited to flavonoids and are observed among other broad categories of chemicals, thus this group of chemicals can be termed as the "estrogenome". This review article focuses on the connection of estrogen action mainly between the outer and the inner environments, which represent variations of chemicals and biological activities/signaling pathways, respectively, and form the basis to understand their applications. The applications of chemicals will markedly progress due to emerging technologies, such as artificial intelligence for precision medicine, which is also true of the study of the estrogenome including estrogenic flavonoids.

Isoflurane Promotes Cell Proliferation, Invasion, and Migration by Regulating BACH1 and miR-375 in Prostate Cancer Cells In Vitro

The aim of this study was to investigate the mechanism of isoflurane in proliferation, invasion, and migration in prostate cancer (PC) cells in vitro by regulating BACH1 and miR-375. The effect of different concentrations of isoflurane (0%, 0.5%, 1%, and 2%) on PC cell proliferation (PC3 and 22RV1) was measured. After PC cells and normal human prostate stromal immortalized WPMY-1 cells were treated with isoflurane, BACH1 and miR-375 expression was measured. Subsequently, PC3 and 22RV1 cells underwent gain- and loss-of-function assays with or without 4-h 2% isoflurane pretreatment. The levels of miR-375, BACH1, and PTEN were assessed. The binding of BACH1 to miR-375 promoter was detected by ChIP assay. Dual-luciferase reporter assay detected the targeting relationship of miR-375 with BACH1 and PTEN. Isoflurane promoted PC3 and 22RV1 cell proliferation. In addition, isoflurane elevated the levels of BACH1 and miR-375 in a dosage-dependent manner in PC cells. Transfection with miR-375 inhibitor or sh-BACH1 repressed PC cell proliferation, invasion, and migration, while exposure to 2% isoflurane for 4 h before transfection counteracted the inhibitory effects of sh-BACH1 or miR-375 inhibitor on PC cells. PTEN expression was suppressed after 2% isoflurane treatment, but the transfection with miR-375 inhibitor partly abrogated this suppressive effect in PC cells. Moreover, BACH1 bound to miR-375 and miR-375 negatively targeted PTEN. miR-375 mimic could partially reverse the inhibitory effects of sh-BACH1 on the proliferation, invasion, and migration of isoflurane-treated PC cells. Isoflurane facilitated PC cell proliferation, migration, and invasion by activating BACH1 to upregulate miR-375.

Perspectives on the Role of Non-Coding RNAs in the Regulation of Expression and Function of the Estrogen Receptor

Estrogen receptors (ERs) comprise several nuclear and membrane-bound receptors with different tissue-specific functions. ERα and ERβ are two nuclear members of this family, whereas G protein-coupled estrogen receptor (GPER), ER-X, and Gq-coupled membrane estrogen receptor (Gq-mER) are membrane-bound G protein-coupled proteins. ERα participates in the development and function of several body organs such as the reproductive system, brain, heart and musculoskeletal systems. ERβ has a highly tissue-specific expression pattern, particularly in the female reproductive system, and exerts tumor-suppressive roles in some tissues. Recent studies have revealed functional links between both nuclear and membrane-bound ERs and non-coding RNAs. Several oncogenic lncRNAs and miRNAs have been shown to exert their effects through the modulation of the expression of ERs. Moreover, treatment with estradiol has been shown to alter the malignant behavior of cancer cells through functional axes composed of non-coding RNAs and ERs. The interaction between ERs and non-coding RNAs has functional relevance in several human pathologies associated with estrogen regulation, such as cancers, intervertebral disc degeneration, coronary heart disease and diabetes. In the current review, we summarize scientific literature on the role of miRNAs and lncRNAs on ER-associated signaling and related disorders.

Medical findings of nasopharyngeal carcinoma patients and anti-tumor benefits of formononetin

Epidemiologically, a malignancy of nasopharyngeal carcinoma (NPC) is endemic in worldwide, characterized with high invasiveness and lethality. Formononetin (FN), an anti-tumor bioactive component, is found to exert anti-proliferative activity against NPC cells. However, the invasive pharmacological activities of FN against NPC have not yet been investigated. In this study, the human NPC data and samples were used for further assays. In addition, a human cell line of CNE2 was used to evaluate the anti-invasive effects of formononetin and the underlying mechanism. As results, advanced NPC patients were diagnosed through validation of blood tumor markers and medical images, and the results showed increased Lamin A/C and cytokeratin 19 (CK19) expressions in carcinomatous sections. In experimental study in vitro, FN-treated CNE2 cells exhibited inhibited cellular proliferation, promoted cell apoptosis, and decreased would healing process, reduced cellular migratory capability, respectively. Furthermore, FN-treated CNE2 cells resulted in down-regulated expressions of b-cell lymphoma-2 (Bcl-2), extracellular regulated protein kinases1/2 (ERK1/2), Lamin A/C and CK19 in a dose-dependent manner, while intracellular Bax expression was elevated. Taken together, these clinical findings elucidate invasive characteristics of human NPC samples. Further, the anti-proliferative and invasive benefits of FN were achieved through suppression of cellular ERK1/2 pathway and inactivation of intracellular Lamin A/C signaling in NPC cells.

Formononetin: A Review of Its Anticancer Potentials and Mechanisms

Cancer, a complex yet common disease, is caused by uncontrolled cell division and abnormal cell growth due to a variety of gene mutations. Seeking effective treatments for cancer is a major research focus, as the incidence of cancer is on the rise and drug resistance to existing anti-cancer drugs is major concern. Natural products have the potential to yield unique molecules and combinations of substances that may be effective against cancer with relatively low toxicity/better side effect profile compared to standard anticancer therapy. Drug discovery work with natural products has demonstrated that natural compounds display a wide range of biological activities correlating to anticancer effects. In this review, we discuss formononetin (C₁₆H₁₂O₄), which originates mainly from red clovers and the Chinese herb Astragalus membranaceus. The compound comes from a class of 7-hydroisoflavones with a substitution of methoxy group at position 4. Formononetin elicits antitumorigenic properties in vitro and in vivo by modulating numerous signaling pathways to induce cell apoptosis (by intrinsic pathway involving Bax, Bcl-2, and caspase-3 proteins) and cell cycle arrest (by regulating mediators like cyclin A, cyclin B1, and cyclin D1), suppress cell proliferation [by signal transducer and activator of transcription (STAT) activation, phosphatidylinositol 3-kinase/protein kinase-B (PI3K/AKT), and mitogen-activated protein kinase (MAPK) signaling pathway], and inhibit cell invasion [by regulating growth factors vascular endothelial growth factor (VEGF) and Fibroblast growth factor 2 (FGF2), and matrix metalloproteinase (MMP)-2 and MMP-9 proteins]. Co-treatment with other chemotherapy drugs such as bortezomib, LY2940002, U0126, sunitinib, epirubicin, doxorubicin, temozolomide, and metformin enhances the anticancer potential of both formononetin and the respective drugs through synergistic effect. Compiling the evidence thus far highlights the potential of formononetin to be a promising candidate for chemoprevention and chemotherapy.

Formononetin and metformin act synergistically to inhibit growth of MCF-7 breast cancer cells in vitro

Many breast cancer patients suffer from obvious side effects induced by chemotherapy. Formononetin (FM), one kind ingredient of Chinese herbal medicine, has been suggested to inhibit MCF-7 breast cancer cells. And recently metformin (MET) has gained more attention as a potential anti-cancer drug. The aim of this study was to investigate the synergistic effects of FM and MET on the proliferation of MCF-7 cells and to clarify the possible molecular mechanism involved. MCF-7 cells were treated with various concentrations of FM (40 and 80 μM) or FM (40 and 80 μM) combined with MET (150 μM) for 48 h. Cell proliferation was tested by an methyl tetrazolium (MTT) (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) assay. The percentage of apoptotic cells was measured by flow cytometry. The expression level of b-cell lymphoma/leukemia-2 (bcl-2) mRNA was examined by RT-PCR, while the expression levels of phosphorylated extracellular signal-regulated kinases (p-ERK1/2) and bcl-2 protein were detected by Western blotting. Compared with untreated cells, 40 μM and 80 μM FM efficiently inhibited proliferation and increased apoptosis in MCF-7 cells. Additionally, 40 μM and 80 μM FM greatly downregulated bcl-2 mRNA expression when compared with untreated cells. Furthermore, the protein expression of bcl-2 and p-ERK1/2 was significantly reduced by 40 μM and 80 μM FM. The cytotoxic effect of FM was more remarkable when 150 μM MET was added. Taken together, the combinational use of FM and MET enhanced cell growth inhibition, and the induction of apoptosis in MCF-7 cells mediated by the ERK1/2 signaling pathway.