PMID: 

Chemotherapy. 2018 ;63(3):155-161. Epub 2018 Jun 22. PMID: 29936511

Abstract Title: 

Isoliquiritigenin Suppresses Osteosarcoma U2OS Cell Proliferation and Invasion by Regulating the PI3K/Akt Signalling Pathway.

Abstract: 

AIMS: Isoliquiritigenin (ISL) is a flavonoid, that has been shown to have antioxidant, vasorelaxant, anti-inflammatory, and antitumor activities. This study aimed to explore the antitumor effect of ISL on human osteosarcoma U2OS cells and investigate the mechanism of this effect.METHODS: The effect of ISL on osteosarcoma U2OS cell proliferation, invasion, migration, and apoptosis were determined by a CCK8 assay, a transwell invasion assay, a transwell migration assay, and fluorescence-activated cell sorting, respectively. In addition, the protein expression levels of Bcl2, Bax, active Caspase-3, Akt, mTOR, p70, and Cyclin D1 were detected by western blotting.RESULTS: ISL suppressed cell proliferation, inhibited invasion and migration, and promoted apoptosis in U2OS cells. After treatment with ISL, the protein expression levels of Bax and active Caspase-3 increased, while the level of Bcl-2 declined significantly. Furthermore, the phosphorylation levels of Akt and mTOR declined significantly compared with that of the control.CONCLUSION: ISL could retard proliferation and promote apoptosis of U2OS cells possibly by suppressing the PI3K/Akt signalling pathway, indicating that it might be a potential therapeutic agent for osteosarcoma treatment.

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PMID: 

Inflammopharmacology. 2019 Aug ;27(4):809-816. Epub 2018 Jun 26. PMID: 29943151

Abstract Title: 

Protective effect of isoliquiritigenin against cerebral injury in septic mice via attenuation of NF-κB.

Abstract: 

BACKGROUND: The study was conducted to scrutinize the outcome of isoliquiritigenin (ISL) against cerebral injury in septic mice.METHODS: The sepsis was introduced using cecal ligation and puncture (CLP) method in experimental mice. The effect of ISL was quantified using the content of brain water and blood brain barrier (BBB) permeability. The effect on the levels of myeloperoxidase (MPO), superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) in brain homogenates was also determined. The effect of ISL on the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 in serum was also estimated. The levels of various inflammatory biomarkers (COX-2 and PGE2) were also studied. The expression of NF-κB signalling cascade and inducible nitric oxide synthase (iNOS) was estimated by Western blot.RESULTS: Compared with CLP group, the brain water content was found to be reduced significantly together with the enhanced BBB integrity in ISL treated group. The level of MDA was reduced together with enhanced level of SOD and GSH in the ISL treated group. The levels of TNF-α, IL-1β, and IL-6 were also found to be modulated in ISL group. The level of COX-2 and PGE2 was reduced to near normal after ISL administration together with increase in the IκBα expression and reduction of p65 and p-p65 expression in a concentration-dependent manner. The expression of iNOS wasalso found to be reduced in ISL group.CONCLUSION: These results demonstrate that ISL causes protection of CLP-induced sepsis in experimental mice via multiple pathways.

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PMID: 

Mol Med Rep. 2018 Sep ;18(3):3429-3436. Epub 2018 Jul 25. PMID: 30066879

Abstract Title: 

Isoliquiritigenin inhibits proliferation and metastasis of MKN28 gastric cancer cells by suppressing the PI3K/AKT/mTOR signaling pathway.

Abstract: 

Isoliquiritigenin (ISL) is aflavonoid extracted from licorice root, which is known to serve important antitumor roles in numerous types of cancers; however, its effect on gastric cancer remains to be elucidated. The present study aimed to explore the roles and underlying mechanisms of ISL in MKN28 gastric cancer cells. MKN28cell proliferation was measured using the Cell Counting Kit‑8 (CCK8) assay. A Transwell assay was used to determine the effects of ISL on the migration and invasion of MKN28 cells. Apoptosis was assessed by flow cytometry, and the expression levels of apoptosis‑, autophagy‑ and signaling pathway‑related proteins were detected by western blot analysis. The results of the CCK8 assay demonstrated that ISL significantly inhibited the proliferation of MKN28 cells (P

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PMID: 

J Exp Clin Cancer Res. 2018 Aug 6 ;37(1):184. Epub 2018 Aug 6. PMID: 30081934

Abstract Title: 

Isoliquiritigenin suppresses human melanoma growth by targeting miR-301b/LRIG1 signaling.

Abstract: 

BACKGROUND: Isoliquiritigenin (ISL), a natural flavonoid isolated from the root of licorice (Glycyrrhiza uralensis), has shown various pharmacological properties including anti-oxidant, anti-inflammatory and anti-cancer activities. MicroRNAs (miRNAs), a class of small non-coding RNAs, have been reported as post-transcriptional regulators with altered expression levels in melanoma. This study aims to investigate the anti-melanoma effect of ISL and its potential mechanism.METHODS: We investigated the effect of ISL on the proliferation and apoptosis of melanoma cell lines with functional assays, such as CCK-8 assay, colony formation assay and flow cytometry. The protein level of apoptosis related genes were measured by western blotting. High-throughput genome sequencing was used for screening differentially expressed miRNAs of melanoma cell lines after the treatment of ISL. We performed functional assays to determine the oncogenic role of miR-301b, the most differentially expressed miRNA, and its target gene leucine rich repeats and immunoglobulin like domains 1 (LRIG1), confirmed by bioinformatic analysis, luciferase reporter assay, western blotting and immunohistochemical assay in melanoma. Immunocompromised mouse models were used to determine the role of miR-301b and its target gene in melanoma tumorigenesis in vivo. The relationship between miR-301b and LRIG1 was further verified in GEO data set and tissue specimens.RESULTS: Functional assays indicated that ISL exerted significant growth inhibition and apoptosis induction on melanoma cells. MiR-301b is the most differentially expressed miRNA after the treatment of ISL and significantly downregulated. The suppressive effect of ISL on cell growth is reversed by ectopic expression of miR-301b. Intratumorally administration of miR-301b angomir enhances the inhibitory effect of ISL on tumor growth in vivo. Bioinformatic analysis showed that miR-301b may target LRIG1, miR-301b suppresses the luciferase activity of reporter constructs containing 3'UTR of LRIG1 as well as the expression level of LRIG1. And the anti-cancer effect of ISL is mitigated when LRIG1 is silenced in vivo and in vitro. Analysis of the melanoma samples obtained from patients shows that LRIG1 is negatively correlated with miR-301b.CONCLUSIONS: ISL may inhibit the proliferation of melanoma cells by suppressing miR-301b and inducing its target LRIG1.

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PMID: 

Front Pharmacol. 2018 ;9:936. Epub 2018 Aug 17. PMID: 30174606

Abstract Title: 

Isoliquiritigenin Protects Against Pancreatic Injury and Intestinal Dysfunction After Severe Acute Pancreatitis via Nrf2 Signaling.

Abstract: 

Severe acute pancreatitis (SAP) is a digestive system disease that is associated with a range of complications including intestinal dysfunction. In this study, we determined that the chalcone compound, isoliquiritigenin (ISL), reduces pancreatic and intestinal injury in a mouse model of SAP. These effects were achieved by suppressing oxidative stress and the inflammatory responses to SAP. This was evidenced by a reduction in histological score, and malondialdehyde (MDA), interleukin (IL)-6, tumor necrosis factor (TNF)-α and cleaved-caspase-3 (c-caspase-3) protein along with an increase in Nrf2, hemeoxygenase-1 (HO-1), quinone oxidoreductase 1 (NQO1), and superoxide dismutase (SOD). We then used Nrf2mice to test the protective effect of Nrf2 during ISL treatment of SAP. Our results indicated that Nrf2mice had greater pancreatic injury and intestinal dysfunction than wild-type mice. They also had reduced adherens junctions (P120-catenin) and tight junctions (occludin), and increased activated nuclear factor-κB (NF-κB) protein. In Nrf2mice, ISL was less effective at these functions than in the WT mice. In conclusion, this study demonstrated that ISL exerts its protective effects against oxidative stress and inflammatory injury after SAP via regulation of the Nrf2/NF-κB pathway. It also showed that the efficacy of ISL in repairing the intestinal barrier damage caused by SAP is closely related to the Nrf2 protein. Our findings demonstrated that Nrf2 is an important protective factor against SAP-induced injuries in the pancreas and intestines.

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PMID: 

Zhejiang Da Xue Xue Bao Yi Xue Ban. 2018 May 25 ;47(2):181-186. PMID: 30226314

Abstract Title: 

[Isoliquiritigenin can inhibit migration and invasion of human glioma stem cells by down-regulating matrix metalloproteinases].

Abstract: 

OBJECTIVE: To investigate the effects of isoliquiritigenin on the migration and invasion of human glioma stem cells and the underlying mechanism.METHODS: The stem cell markers CD133 and Nestin in SHG44 human glioma stem cells were examined with immunofluorescence microscopy. The migration and invasion ability of glioma stem cells was determined by transwell method. The mRNA and protein expression of matrix metalloproteinase (MMP)-2 and MMP-9 were detected by real-time RT-PCR and Western blot, respectively.RESULTS: CD133 and Nestin were positive in SHG44 cells. The number of migrated cells in SHG44 cells treated with 20 and 80μmol/L isoliquiritigenin for 48 h were significantly lower than that in control group (76±5 and 42±4 vs. 85±6, all

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PMID: 

J Exp Clin Cancer Res. 2018 Oct 3 ;37(1):243. Epub 2018 Oct 3. PMID: 30285892

Abstract Title: 

Suppression of lung cancer progression by isoliquiritigenin through its metabolite 2, 4, 2', 4'-Tetrahydroxychalcone.

Abstract: 

BACKGROUND: Licorice is an herb extensively used for both culinary and medicinal purposes. Various constituents of licorice have been shown to exhibit anti-tumorigenic effect in diverse cancer types. However, majority of these studies focus on the aspect of their growth-suppressive role. In this study, we systematically analyzed known licorice's constituents on the goal of identifying component(s) that can effectively suppress both cell migration and growth.METHODS: Effect of licorice's constituents on cell growth was evaluated by MTT assay while cell migration was assessed by both wound-healing and Transwell assays. Cytoskeleton reorganization and focal adhesion assembly were visualized by immunofluorescence staining with labeled phalloidin and anti-paxillin antibody. Activity of Src in cells was judged by western blot using phosphor-Src416 antibody while Src kinase activity was measured using Promega Src kinase assay system. Anti-tumorigenic capabilities of isoliquiritigenin (ISL) and 2, 4, 2', 4'-Tetrahydroxychalcone (THC) were investigated using lung cancer xenograft model.RESULTS: Using a panel of lung cancer cell lines, ISL was identified as the only licorice's constituent capable of inhibiting both cell migration and growth. ISL-led inhibition in cell migration resulted from impaired cytoskeleton reorganization and focal adhesion assembly. Assessing the phosphorylation of 141 cytoskeleton dynamics-associated proteins revealed that ISL reduced the abundance of Tyr421-phosphorylation of cortactin, Tyr925- and Tyr861-phosphorylation of FAK, indicating the involvement of Src because these sites are known to be phosphorylated by Src. Enigmatically, ISL inhibited Src in cells while displayed no effect on Src activity in cell-free system. The discrepancy was explained by the observation that THC, one of the major ISL metabolite identified in lung cancer cells abrogated Src activity both in cells and cell-free system. Similar to ISL, THC deterred cell migration and abolished cytoskeleton reorganization/focal adhesion assembly. Furthermore, we showed both ISL and THC suppressed in vitro lung cancer cell invasion and in vivo tumor progression.CONCLUSION: Our study suggests that ISL inhibits lung cancer cell migration and tumorigenesis by interfering with Src through its metabolite THC. As licorice is safely used for culinary purposes, our study suggests that ISL or THC may be safely used as a Src inhibitor.

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PMID: 

Int Immunopharmacol. 2018 Dec ;65:64-75. Epub 2018 Oct 2. PMID: 30290368

Abstract Title: 

Isoliquiritigenin protects against blood‑brain barrier damage and inhibits the secretion of pro-inflammatory cytokines in mice after traumatic brain injury.

Abstract: 

Traumatic brain injury (TBI) caused by an external mechanical force acting on the brain is a serious neurological condition. Inflammation plays an important role in prolonging secondary tissue injury after TBI, leading to neuronal cell death and dysfunction. Isoliquiritigenin (ILG) is a flavonoid monomer with anti-inflammatory characteristic. Thus, we had investigated the potential protective effects of ILG on TBI-induced injuries and identified the mechanisms underlying it. Here, we have demonstrated that ILG preserves blood brain barrier (BBB) integrity in vivo, suppresses the activation of microglia and inflammatory responses in mice after TBI, consequently leading to neurofunctional deficits, brain oedema, structural damage, and macrophage infiltration. In vitro, ILG exerts anti-inflammatory effect, and upregulates tight junction proteins 120‑β‑catenin and occludin in SH‑SY5Y cells under oxygen glucose deprivation/reoxygenation (OGD/D) condition. Additionally, we found that PI3K/AKT/GSK‑3β signalling pathway is involved in ILG treatment for TBI. To further confirm it, we had used SC79 (ethyl 2‑amino‑6‑chloro‑4‑(1‑cyano‑2‑ethoxy‑2‑oxoethyl)‑4H‑chromene‑3‑carboxylate), an Akt specific activator, to activate Akt, we found that SC79 partially reduces the protective effect of ILG for TBI. Overall, our current study reveals the neuroprotective role of ILG on TBI-induced BBB damage, downregulated tight junction proteins via PI3K/AKT/GSK‑3β signalling pathway. Furthermore, ILG suppresses the secretion of pro-inflammatory cytokines after TBI through inhibiting the PI3K/AKT/GSK‑3β/NF‑κB signalling pathway. Our findings suggest that GSK‑3β is a key regulatory factor during TBI-induced secretion of inflammatory cytokines, neuronal apoptosis and destruction of BBB.

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PMID: 

Front Pharmacol. 2018 ;9:1001. Epub 2018 Sep 20. PMID: 30294270

Abstract Title: 

Isoliquiritigenin Inhibits Cigarette Smoke-Induced COPD by Attenuating Inflammation and Oxidative Stress via the Regulation of the Nrf2 and NF-κB Signaling Pathways.

Abstract: 

Chronic obstructive pulmonary disease (COPD) is the major leading cause of disease with high-mortality worldwide. Cigarette smoke (CS) is a major factor for COPD. CS causes chronic inflammation and oxidative stress, which contributes to lung dysfunction in COPD. Isoliquiritigenin (ILG), a natural flavonoid derived from the root of liquorice, has been reported to possess antiinflammatory and antioxidant activity. In the present study, we tested the mechanism and protective effects of ILG on CS-induced COPD. Mice were exposed to CS for 2 h twice a day for 4 weeks. ILG was given orally 1 h before CS exposure twice a day for 4 weeks. The bronchial alveolar lavage fluid was collected to test the levels of inflammatory cytokines and the number of inflammatory cells. The lung tissues were obtained to evaluate the pathological changes, lung edema, myeloperoxidase (MPO) activity, malondialdehyde (MDA) level, as well as the expression of the nuclear factor-erythroid 2 (Nrf2) and nuclear factorκB (NF-κB) signaling pathways. The results showed that ILG reduced the infiltration of inflammatory cells and the production of inflammatory cytokines. ILG also reversed CS-induced lung pathological injuries, wet/dry ratio, MPO activity, and MDA level. Further research also showed that ILG dose-dependently up-regulated the expression of Nrf2 and down-regulated the expression of NF-κB signaling pathways induced by CS. In conclusion, ILG protected against CS-induced COPD by inhibiting inflammatory and oxidative stress via the regulation of the Nrf2 and NF-κB signaling pathways.

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PMID: 

Eur J Pharmacol. 2018 Dec 15 ;841:90-97. Epub 2018 Oct 16. PMID: 30339814

Abstract Title: 

Isoliquiritigenin-mediated p62/SQSTM1 induction regulates apoptotic potential through attenuation of caspase-8 activation in colorectal cancer cells.

Abstract: 

Isoliquiritigenin (ISL) is a natural flavonoid that exhibits anticancer properties in various carcinoma cell types. However, the precise mechanism responsible for its anticancer activity has not been elucidated fully. In the present study, we examined ISL-mediated apoptotic mechanisms in colorectal cancer (CRC) cells. ISL induced apoptosis in human HCT-116 cells and caused marked induction of p62/SQSTM1 mRNA and protein expression. Similarly, ISL potently inhibited in vivo tumor growth and induced p62/SQSTM1 expression in xenograft tumor tissues. In a p62/SQSTM1 siRNA transfection study, ISL-induced p62/SQSTM1 expression attenuated ISL-mediated apoptosis by reducing caspase-8 activation. ISL potentiated the apoptotic effects of 5-fluorouracil (5-FU) on HCT-116 cells. However, ISL-induced p62/SQSTM1 expression also attenuated the potency of apoptosis induced by the combination of 5-FU and ISL. Our results demonstrate that ISL-induced p62/SQSTM1 upregulation affects ISL-mediated apoptotic potential through attenuation of caspase-8 activation in CRC cells. These findings broaden the understanding of the molecular basis of ISL-mediated apoptosis.

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