PMID: 

Oncol Rep. 2014 Feb ;31(2):755-62. Epub 2013 Dec 16. PMID: 24337492

Abstract Title: 

Licochalcone A induces apoptosis in KB human oral cancer cells via a caspase-dependent FasL signaling pathway.

Abstract: 

Licochalcone A (Lico-A) is a natural phenol licorice compound with multiple bioactivities, including anti-inflammatory, anti-microbial, anti-fungal and osteogenesis-inducing properties. In the present study, we investigated the Lico-A-induced apoptotic effects and examined the associated apoptosis pathway in KB human oral cancer cells. Lico-A decreased the number of viable KB oral cancer cells. However, Lico-A did not have an effect on primary normal human oral keratinocytes. In addition, the IC50 value of Lico-A was determined to be ~50µM following dose-dependent stimulation. KB oral cancer cells stimulated with Lico-A for 24 h showed chromatin condensation by DAPI staining, genomic DNA fragmentation by agarose gel electrophoresis and a gradually increased apoptotic cell population by FACS analysis. These data suggest that Lico-Ainduces apoptosis in KB oral cancer cells. Additionally, Lico‑A‑induced apoptosis in KB oral cancer cells was mediated by the expression of factor associated suicide ligand (FasL) and activated caspase-8 and -3 and poly(ADP-ribose) polymerase (PARP). Furthermore, in the KB oral cancer cells co-stimulation with a caspase inhibitor (Z-VAD-fmk) and Lico-A significantly abolished the apoptotic phenomena. Our findings demonstrated that Lico‑A-induced apoptosis in KB oral cancer cells involves the extrinsic apoptotic signaling pathway, which involves a caspase-dependent FasL-mediated death receptor pathway. Our data suggest that Lico-A be developed as a chemotherapeutic agent for the management of oral cancer.

read more

PMID: 

PLoS One. 2014 ;9(1):e86537. Epub 2014 Jan 22. PMID: 24466137

Abstract Title: 

Licochalcone A suppresses migration and invasion of human hepatocellular carcinoma cells through downregulation of MKK4/JNK via NF-κB mediated urokinase plasminogen activator expression.

Abstract: 

Hepatocellular cell carcinoma (HCC) is one of the most commonly diagnosed cancers worldwide and in Taiwan. Chemoprevention of cancer with dietary bioactive compounds could potentially reverse, suppress, or prevent cancer progression. Licochalcone A (LicA) is a characteristic chalcone of licorice, which is the root of Glycyrrhiza inflate. It had been reported that LicA has anti-inflammatory, anti-microbial, and anti-tumor properties. However, the effects of LicA on the migration and invasion of human HCC cells have not yet been reported. In the present study, it was found that LicA inhibits the migratory and invasion ability of SK-Hep-1 and HA22T/VGH cells in a dose-dependent manner, as assessed by the cell migration and Matrigel cell invasion assay. Using casein zymography, Western blotting, reverse transcriptase polymerase chain reaction, and an immunofluorescence assay, it was found that LicA induces a dose-dependent inhibition of uPA activity and expression, as well as reduces mRNA levels in SK-Hep-1 and HA22T/VGH cells. LicA was also found to inhibit the expression of phosphor-JNK and phosphor-MKK4 in SK-Hep-1 cells. Furthermore, LicA significantly decreased uPA levels in SP600125-treated or si-MKK4-transfected cells alongside a marked reduction in cell migration and invasion, which supports the notion that an inhibition of MKK4/JNK results in anti-metastatic effects. Moreover, LicA inhibited the expression of nuclear NF-κB, as well as the binding ability of NF-κB to the uPA promoter. These findings further our understanding of the role of LicA in suppressing tumor metastasis and its underlying molecular mechanisms, as well as suggest that LicA may be a promising anti-metastatic agent.

read more

PMID: 

Tumour Biol. 2014 Jul ;35(7):6549-55. Epub 2014 Apr 2. PMID: 24691971

Abstract Title: 

Licochalcone A as a potent antitumor agent suppresses growth of human oral cancer SCC-25 cells in vitro via caspase-3 dependent pathways.

Abstract: 

The majority of anticancer drugs are of natural origin. However, it is unknown whether licochalcone A is cytotoxic towards oral squamous cell carcinoma (OSCC) cells. The goal of this study was to investigate the cytotoxic effects of licochalcone A on the human OSCC SCC-25 cells and to identify the underlying molecular mechanism. Exposure of SCC-25 cells to licochalcone A dose- and time-dependently decreased cell viability by arresting cell cycle at the S and G2/M phase as well as inducing apoptosis. Furthermore, the proapoptotic activity of licochalcone A was revealed by DNA fragmentation. Concomitantly, we observed activation of the effector caspases-3, induced by activation of the initiator caspases -8 and -9, which subsequent trigger both death receptor pathway and the mitochondrial apoptotic pathway in licochalcone A-mediated SCC-25 cell apoptosis. Besides, treatment with 50μg/mL of licochalcone A for 36 h led to the cleavage of PARP, an indicator of apoptosis induction. Therefore licochalcone A may be a good candidate for development as a possible chemopreventive agent against OSCC.

read more

PMID: 

Tumour Biol. 2014 Aug ;35(8):7467-74. Epub 2014 May 1. PMID: 24789273

Abstract Title: 

Antimetastatic effects of licochalcone A on oral cancer via regulating metastasis-associated proteases.

Abstract: 

Licochalcone A, a major phenolic constituent of the licorice species Glycyrrhiza inflata, has been proven to possess various biological benefits including anti-cancer activity. However, the detailed effects and molecular mechanisms of licochalcone A on the invasiveness and metastasis of oral cancer cells have not been fully understood. Thus, SCC-25 oral cancer cells were subjected to a treatment with licochalcone A at indicated concentrations (25, 50, and 100μg/mL) for 36 h and then analyzed for the effect of licochalcone A on the cell migration and invasion. In vitro assays, including wound healing, cell adhesion, and cell invasion/migration assays, revealed that licochalcone A treatment significantly inhibited the cell migration/invasion capacities of SCC-25 cells. Also, results of zymography and Western blotting showed that activity and protein level of matrix metalloproteinase-2 (MMP-2) was suppressed, but TIMP-2 level was increased, indicating the important role of MMP-2 and TIPM-2 in anti-metastatic regulation of SCC-25 cells. Furthermore,licochalcone A was shown to suppress the nuclear factor-kappa B (NF-κB) signal, as evidenced by the decreased expression of phosphorylated p65 (p-65) protein in licochalcone A-treated SCC-25 cells. Notably, we also found that licochalcone A treatment increased the expression of the epithelial marker E-cadherin and decreased the expression of mesenchymal markers N-cadherin in SCC-25 cells. This is the first report describing the effects and possible mechanisms of licochalcone A on tumor invasion and metastasis of SCC-25 cells. Taken together, our findings support that licochalcone A can be developed to a potent anti-metastatic candidate for oral cancer therapy.

read more

PMID: 

Nutr Res Pract. 2014 Jun ;8(3):257-66. Epub 2014 May 15. PMID: 24944769

Abstract Title: 

Anti-carcinogenic effects of non-polar components containing licochalcone A in roasted licorice root.

Abstract: 

BACKGROUND/OBJECTIVE: Licorice has been shown to possess cancer chemopreventive effects. However, glycyrrhizin, a major component in licorice, was found to interfere with steroid metabolism and cause edema and hypertension. The roasting process of licorice modifies the chemical composition and converts glycyrrhizin to glycyrrhetinic acid. The purpose of this study was to examine the anti-carcinogenic effects of the ethanol extract of roasted licorice (EERL) and to identify the active compound in EERL.MATERIALS/METHODS: Ethanol and aqueous extracts of roasted and un-roasted licorice were prepared. The active fraction was separated from the methylene chloride (MC)-soluble fraction of EERL and the structure of the purified compound was determined by nuclear magnetic resonance spectroscopy. The anti-carcinogenic effects of licorice extracts and licochalcone A was evaluated using a MTT assay, Western blot, flow cytometry, and two-stage skin carcinogenesis model.RESULTS: EERL was determined to be more potent and efficacious than the ethanol extract of un-roasted licorice in inhibiting the growth of DU145 and MLL prostate cancer cells, as well as HT-29 colon cancer cells. The aqueous extracts of un-roasted and roasted licorice showed minimal effects on cell growth. EERL potently inhibited growth of MCF-7 and MDA-MB-231 breast, B16-F10 melanoma, and A375 and A2058 skin cancer cells, whereas EERL slightly stimulated the growth of normal IEC-6 intestinal epithelial cells and CCD118SK fibroblasts. The MC-soluble fraction was more efficacious than EERL in inhibiting DU145 cell growth. Licochalcone A was isolated from the MC fraction and identified as the active compound of EERL. Both EERL and licochalcone A induced apoptosis of DU145 cells. EERL potently inhibited chemically-induced skin papilloma formation in mice.CONCLUSIONS: Non-polar compounds in EERL exert potent anti-carcinogenic effects, and that roasted rather than un-roasted licorice should be favored as a cancer preventive agent, whether being used as an additive to food or medicine preparations.

read more

PMID: 

Tumour Biol. 2014 Dec ;35(12):12139-49. Epub 2014 Aug 23. PMID: 25149157

Abstract Title: 

Licochalcone A inhibits the migration and invasion of human lung cancer cells via inactivation of the Akt signaling pathway with downregulation of MMP-1/-3 expression.

Abstract: 

Licochalcone A (LicA), a major phenolic constituent of Glycyrrhiza inflata, has been reported to exhibit anti-tumor, anti-inflammatory, and anti-metastatic properties in various cancer cells and animal models. The aim of this study was to determine the anti-tumor effects of LicA on lung cancer cells. The results indicated that LicA exhibited effective inhibition of cell migration and invasion of A549 and H460 cells under non-cytotoxic concentrations. Furthermore, LicA was also found to significantly inhibit the proteins and messenger RNA (mRNA) expression of MMP-1 and MMP-3 in A549 cells. Moreover, treatment of A549 cells with LicA-inhibited activation of the phosphorylation of Akt and inhibition of Akt by LY294002 (PI3K inhibitor) or transfection with the constitutive active-Akt (CA-Akt) expression vector significantly abolished the LicA-inhibited migration and invasion through activation of the Akt pathway. Further mechanistic studies revealed that LicA inhibits Akt signaling pathways and downstream transcription factors Sp1 expression. These findings imply a critical role for Akt inhibition in the LicA-inhibited migration and invasion of lung cancer cells. Thus, LicA might be used as an anti-invasive agent in the treatment of lung cancer.

read more

PMID: 

Exp Dermatol. 2015 Jan ;24(1):42-7. Epub 2014 Dec 8. PMID: 25381913

Abstract Title: 

Licochalcone A activates Nrf2 in vitro and contributes to licorice extract-induced lowered cutaneous oxidative stress in vivo.

Abstract: 

The retrochalcone licochalcone A (LicA) has previously been shown to possess antimicrobial and anti-inflammatory properties. In this study, we focused on pathways responsible for the antioxidative properties of LicA. In vitro, LicA protected from oxidative stress mediated by reactive oxygen species (ROS) by activating the expression of cytoprotective phase II enzymes. LicA induced nuclear translocation of NF-E2-related factor 2 (Nrf2) in primary human fibroblasts and elevated the expression of the cytoprotective and anti-inflammatory enzymes heme oxygenase 1 and glutamate-cysteine ligase modifier subunit. LicA-treated cells displayed a higher ratio of reduced to oxidized glutathione and decreased concentrations of ROS in UVA-irradiated human dermal fibroblasts, as well as in activated neutrophils. In vivo, ultraweak photon emission analysis of skin treated with LicA-rich licorice extract revealed a significantly lowered UVA-induced luminescence, indicative for a decrease in oxidative processes. We conclude from these data that topical application of licorice extract is a promising approach to induce Nrf2-dependent cytoprotection in human skin.

read more

PMID: 

Hepatogastroenterology. 2014 Jul-Aug;61(133):1229-34. PMID: 25436288

Abstract Title: 

Licochalcone-A sensitizes human esophageal carcinoma cells to TRAIL-mediated apoptosis by proteasomal degradation of XIAP.

Abstract: 

BACKGROUND/AIMS: Esophageal carcinoma is one of the most aggressive human cancers, and novel treatment modality is required. Although expressing adequate levels of functional tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptors DR4/DR5, significant proportion of esophageal cancer cells exhibit resistance to the cytotoxic effect of this ligand. Licochalcone-A (LA), a flavonoid present in a variety of edible plants, exhibits a wide spectrum of pharmacologic properties such as anticancer, antioxidant, and anti-inflammatory activities.METHODOLOGY: Eca109 and TE1 cells were cultured and transfected, then their viability was detected using MTT assay. Immunoprecipitation and immunoblotting analysis and RT-PCR analysis were also performed.RESULTS: In this study, we found that LA synergistically caused the TRAIL-induced apoptosis in Eca109 and TE1 cells. Such potentiation was achieved through inhibiting Akt activation and promoting proteasomal degradation of X-linked Inhibitor of Apoptosis Protein (XIAP) which mediated the survival signals and allow the cells to escape from apoptosis in various human cancers.CONCLUSIONS: The combination of TRAIL and LA might be a novel therapeutic strategy for esophageal carcinoma patients who fail to respond to standard chemotherapy.

read more

PMID: 

Food Chem Toxicol. 2015 Mar ;77:34-43. Epub 2015 Jan 5. PMID: 25572524

Abstract Title: 

Licochalcone-A induces intrinsic and extrinsic apoptosis via ERK1/2 and p38 phosphorylation-mediated TRAIL expression in head and neck squamous carcinoma FaDu cells.

Abstract: 

We investigated Licochalcone-A (Lico-A)-induced apoptosis and the pathway underlying its activity in a pharyngeal squamous carcinoma FaDu cell line. Lico-A purified from root of Glycyrrhiza inflata had cytotoxic effects, significantly increasing cell death in FaDu cells. Using a cell viability assay, we determined that the IC50 value of Lico-A in FaDu cells was approximately 100 µM. Chromatin condensation was observed in FaDu cells treated with Lico-A for 24 h. Consistent with this finding, the number of apoptotic cells increased in a time-dependent manner when FaDu cells were treated with Lico-A. TRAIL was significantly up-regulated in Lico-A-treated FaDu cells in adose-dependent manner. Apoptotic factors such as caspases and PARP were subsequently activated in a caspase-dependent manner. In addition, levels of pro-apoptotic factors increased significantly in response to Lico-A treatment, while levels of anti-apoptotic factors decreased. Lico-A-induced TRAIL expression was mediated in part by a MAPK signaling pathway involving ERK1/2 and p38. In xenograft mouse model, Lico-A treatment effectively suppressed the growth of FaDu cell xenografts by activating caspase-3, without affecting the body weight of mice. Taken together, these data suggest that Lico-Ahas potential chemopreventive effects and should therefore be developed as a chemotherapeutic agent for pharyngeal squamous carcinoma.

read more

PMID: 

Int J Oncol. 2015 Mar ;46(3):1385-92. Epub 2015 Jan 13. PMID: 25586190

Abstract Title: 

Licochalcone A induces apoptosis in malignant pleural mesothelioma through downregulation of Sp1 and subsequent activation of mitochondria-related apoptotic pathway.

Abstract: 

Licochalcone A (LCA) is a natural product derived from the roots of Glycyrrhiza inflata exhibiting a wide range of bioactivities such as antitumor, anti-oxidant and anti-bacterial effects. Malignant pleural mesothelioma (MPM) is an extremely aggressive type of cancer with a poor prognosis because of its rapid progression. However, LCA has not been investigated concerning its effects on MPM. Preliminarily, we observed that LCA negatively modulated not only cell growth, but also specificity protein 1 (Sp1) expression in MSTO-211H and H28 cell lines. It was found that IC50 values of LCA for growth inhibition of MSTO-211H and H28 cells were approximately 26 and 30µM, respectively. Consistent with downregulation of Sp1, expression of Sp1 regulatory proteins such as Cyclin D1, Mcl-1 and Survivin was substantially diminished. Mechanistically, LCA triggered the mitochondrial apoptotic pathway by affecting the ratio of mitochondrial proapoptotic Bax to anti-apoptotic Bcl-xL. Bid induced loss of mitochondrial membrane potential, eventually leading to multi-caspase activation and increased sub-G1 population. Moreover, nuclear staining with DAPI highlighted nuclear condensation and fragmentation of apoptotic features. Flow cytometry analyses after staining cells with Annexin V and propiodium iodide corroborated LCA-mediated apoptotic cell death of MPM cells. In conclusion, these results present that LCA may be a potential bioactive material to control human MPM cells by apoptosis via the downregulation of Sp1.

read more