5-7-dihydroxy-6-methoxy-2-phenylchromen-4-one and Liver-Neoplasms

Although oroxylin A, a natural flavonoid compound, suppressed progression of hepatocellular carcinoma, whether the tumor microenvironment especially the communication between cancer cells and immune cells was under its modulation remained obscure. Here we investigated the effect of extracellular vesicles from cancer cells elicited by oroxylin A on macrophages in vitro. The data shows oroxylin A elicits apoptosis-related extracellular vesicles through caspase-3-mediated activation of ROCK1in HCC cells, which regulates M1-like polarization of macrophage. Moreover, oroxylin A downregulates the population of M2-like macrophage and promotes T cells infiltration in tumor microenvironment, accompanied by suppression of HCC development and enhancement of immune checkpoint inhibitor treatment in mice model. Mechanistically, glycolytic proteins enriched in oroxylin A-elicited extracellular vesicles from HCC cells are transferred to macrophages where ROS-dependent NLRP3 inflammasome is activated, therefore contributing to anti-tumor phenotype of macrophage. Taken together, this study highlights that oroxylin A promotes metabolic shifts between tumor cells and immune cells, facilitates to inhibit tumor development, and improves immunotherapy response in HCC model.

Topics: Animals; Carcinoma, Hepatocellular; Extracellular Vesicles; Flavonoids; Liver Neoplasms; Mice; Tumor Microenvironment

Transketolase (TKT), a key rate-limiting enzyme in the non-oxidative branch of the pentose phosphate pathway (PPP), provides more than 85% of the ribose required for de novo nucleotide biosynthesis and promotes the development of hepatocellular carcinoma (HCC). Pharmacologic inhibition of TKT could impede HCC development and enhance treatment efficacy. However, no safe and effective TKT inhibitor has been approved.. An online two-dimensional TKT protein immobilised biochromatographic system was established for high-throughput screening of TKT ligands. Oroxylin A was found to specifically bind TKT. Drug affinity responsive target stability, cellular thermal shift assay, surface plasmon resonance, molecular docking, competitive displacement assay, and site mutation were performed to identify the binding of oroxylin A with TKT. Antitumour effects of oroxylin A were evaluated in vitro, in human xenograft mice, diethylnitrosamine (DEN)-induced HCC mice, and patient-derived organoids (PDOs). Metabolomic analysis was applied to detect the enzyme activity. Transcriptome profiling was conducted to illustrate the anti-HCC mechanism of oroxylin A. TKT knocking-down HCC cell lines and PDOs were established to evaluate the role of TKT in oroxylin A-induced HCC suppression.. By targeting TKT, oroxylin A stabilised the protein to proteases and temperature extremes, decreased its activity and expression, resulted in accumulation of non-oxidative PPP substrates, and activated p53 signalling. In addition, oroxylin A suppressed cell proliferation, induced apoptosis and cell-cycle arrest, and inhibited the growth of human xenograft tumours and DEN-induced HCC in mice. Crucially, TKT depletion exerted identical effects to oroxylin A, and the promising inhibitor also exhibited excellent therapeutic efficacy against clinically relevant HCC PDOs.. These results uncover a unique role for oroxylin A in TKT inhibition, which directly targets TKT and suppresses the non-oxidative PPP. Our findings will facilitate the development of small-molecule inhibitors of TKT and novel therapeutics for HCC.

Topics: Animals; Carcinoma, Hepatocellular; Humans; Liver Neoplasms; Mice; Molecular Docking Simulation; Organoids; Pentose Phosphate Pathway; Transketolase

Hepatocellular carcinoma (HCC), the most prevalent liver cancer, is considered one of the most lethal malignancies with a dismal outcome mainly due to frequent intrahepatic and distant metastasis. In the present study, we demonstrated that oroxylin A, a natural product extracted from Scutellaria radix, significantly inhibits transforming growth factor-beta1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) and metastasis in HCC. Oroxylin A blocked the TGF-β1/Smad signaling via upregulating the non-steroidal anti-inflammatory drug-activated gene-1 (NAG-1) expression. Oroxylin A promoted NAG-1 transcription by regulating the acetylation of CCAAT/enhancer binding protein β (C/EBPβ), a transcription factor that binds to the NAG-1 promoter. In terms of the underlying mechanism, oroxylin A may interact with histone deacetylase 1 (HDAC1) by forming hydrogen bonds with GLY149 residue and induce proteasome-mediated degradation of HDAC1 subsequently impairing HDAC1-mediated deacetylation of C/EBPβ and promoting the expression of NAG-1. Taken together, our findings revealed a previously unknown tumor-suppressive mechanism of oroxylin A. Oroxylin A should be further investigated as a potential clinical candidate for inhibiting HCC metastasis.

Topics: Carcinoma, Hepatocellular; CCAAT-Binding Factor; Cell Line, Tumor; Cell Movement; Epithelial-Mesenchymal Transition; Flavonoids; Growth Differentiation Factor 15; Histone Deacetylase 1; Humans; Liver Neoplasms; Smad Proteins; Transforming Growth Factor beta1

Hepatocellular carcinoma (HCC) is one of the most lethal tumours worldwide. However, the effects of first-line sorafenib treatment in advanced HCC fail to prolong patients' survival due to the highly heterogeneous characteristics of HCC etiology. Cyclin-dependent kinase 9 (CDK9) is an important target in the continuous development of cancer therapy. Here, we demonstrate that CDK9 is closely associated with the progression of HCC and can serve as an HCC therapeutic target by modulating the recovery of wild-type p53 (wt-p53) function. We prove that mouse double minute 2 homologue (MDM2) and Sirtuin 1 (SIRT1) are phosphorylated by CDK9 at Ser166 and Ser47, respectively. Inhibition of CDK9 not only reduces the MDM2-mediated ubiquitination and degradation of wt-p53 but also increases wt-p53 stability by suppressing deacetylase activity of SIRT1. Thus, inhibition of CDK9 promotes the wt-p53 stabilization and prevents HCC progression. However, excessive inhibition by high concentrations of specific CDK9 inhibitors counteracts the promotion of p53 stability and reduces their anti-HCC activity because of extreme general transcription repression. The effects of a novel CDK9 inhibitor named oroxylin A (OA) from Scutellaria baicalensis are explored, with the results indicating that OA shows moderate and controlled inhibition of CDK9 activity and expression, and stabilizes wt-p53 by inhibiting CDK9-regulated MDM2 and SIRT1 signaling. These outcomes indicate the high therapeutic potential of OA against HCC and its low toxicity in normal tissue. This study demonstrates a novel mechanism for the regulation of wt-p53 by CDK9 and indicates that OA is a potential candidate for HCC therapy.

Topics: Animals; Apoptosis; Carcinoma, Hepatocellular; Cyclin-Dependent Kinase 9; Flavonoids; Humans; Liver Neoplasms; Mice; Proto-Oncogene Proteins c-mdm2; Sirtuin 1; Tumor Suppressor Protein p53

Screening active components from Chinese traditional medicine is an effective approach to discover new drugs or active structures. Cell membrane chromatography (CMC), developed rapidly because of its high sensitivity and effectiveness, has achieved a wide application in screening active components on pathological cells or tissues. However, it is hard to clarify the selectivity between pathological and normal tissues through simply using pathological cells. In this study, a novel comparative two-dimensional (2D) cell membrane chromatography system was established. Briefly, hepatic carcinoma HepG2 CMC columns and normal hepatic L02 CMC columns were simultaneously loaded to screen potential selective antitumor components from Scutellariae Radix by comparing the retention behaviors on two kinds of cells. Totally 13 components in Scutellariae Radix retained on both HepG2/ CMC and L02/ CMC columns. Among them, three components, oroxylin A, wogonin and chrysin, were screened out to perform stronger affinity on HepG2 columns, and in further cell proliferation assay, IC

Topics: Antineoplastic Agents, Phytogenic; Carcinoma, Hepatocellular; Cell Membrane; Cell Proliferation; Chromatography, High Pressure Liquid; Drug Screening Assays, Antitumor; Drugs, Chinese Herbal; Flavanones; Flavonoids; Hep G2 Cells; Humans; Inhibitory Concentration 50; Liver Neoplasms; Mass Spectrometry; Scutellaria baicalensis

Topics: Andrographis; Antineoplastic Agents, Phytogenic; Apigenin; Apocynaceae; Asia, Southeastern; Biflavonoids; Bignoniaceae; Catechin; Diterpenes; Ethnopharmacology; Flavanones; Flavonoids; Hep G2 Cells; Humans; Lamiaceae; Liver Neoplasms; Metabolomics; Plants, Medicinal; Proanthocyanidins

Liver cancer is the second cause of death from cancer worldwide, without effective treatment. Traditional chemotherapy for liver cancer has big side effects for patients, whereas targeted drugs, such as sorafenib, commonly have drug resistance. Oroxylin A (OA) is the main bioactive flavonoids of Scutellariae radix, which has strong anti-hepatoma effect but low toxicity to normal tissue. To date, no differentiation-inducing agents have been reported to exert a curative effect on solid tumors. Here our results demonstrated that OA restrained the proliferation and induced differentiation of hepatoma both in vitro and in vivo, via inducing a high PKM1 (pyruvate kinase M1)/PKM2 (pyruvate kinase M2) ratio. In addition, inhibited expression of polypyrimidine tract-binding protein by OA was in charge of the decrease of PKM2 and increase of PKM1. Further studies demonstrated that increased PKM1 translocated into the nucleus and bound with HNF-4α (hepatocyte nuclear factor 4 alpha) directly, promoting the transcription of HNF-4α-targeted genes. This work suggested that OA increased PKM1/PKM2 ratio, resulting in HNF-4α activation and hepatoma differentiation. Especially, OA showed reliable anticancer effect on both human primary hepatocellular carcinoma cells and patient-derived tumor xenograft model for hepatoma, and slowed down the development of primary hepatoma, suggesting that OA could be developed into a novel differentiation inducer agent for hepatoma.

Topics: Carcinoma, Hepatocellular; Carrier Proteins; Cell Differentiation; Flavonoids; Hep G2 Cells; Hepatocyte Nuclear Factor 4; Humans; Liver Neoplasms; Membrane Proteins; Neoplasm Proteins; Thyroid Hormone-Binding Proteins; Thyroid Hormones

Metabolic alteration in cancer cells is one of the most conspicuous characteristics that distinguish cancer cells from normal cells. In this study, we investigated the influence and signaling ways of oroxylin A affecting cancer cell energy metabolism under hypoxia. The data showed that oroxylin A remarkably reduced the generation of lactate and glucose uptake under hypoxia in HepG2 cells. Moreover, oroxylin A inhibited HIF-1α expression and its stability. The downstream targets (PDK1, LDHA, and HK II), as well as their mRNA levels were also suppressed by oroxylin A under hypoxia. The silencing or the overexpression of HIF-1α assays suggested that HIF-1α is required for metabolic effect of oroxylin A in HepG2 cells during hypoxia. Furthermore, oroxylin A could reduce the expression of complex III in mitochondrial respiratory chain, and then decrease the accumulation of ROS at moderate concentrations (0-50 µM) under hypoxia, which was benefit for its inhibition on glycolytic activity by decreasing ROS-mediated HIF-1 expression. Besides, oroxylin A didn't cause the loss of MMP under hypoxia and had no obvious effects on the expression of OXPHOS complexes, suggesting that oroxylin A did not affect mitochondrial mass at the moderate stress of oroxylin A. The suppressive effect of oroxylin A on glycolysis led to a significantly repress of ATP generation, for ATP generation mostly depends on glycolysis in HepG2 cells. This study revealed a new aspect of glucose metabolism regulation of oroxylin A under hypoxia, which may contribute to its new anticancer mechanism. © 2015 Wiley Periodicals, Inc.

Topics: Carcinoma, Hepatocellular; Cell Hypoxia; Energy Metabolism; Flavonoids; Gene Expression Regulation, Neoplastic; Glucose; Glycolysis; Hep G2 Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Lactic Acid; Liver Neoplasms; Reactive Oxygen Species; Signal Transduction

Metabolic alteration in cancer cells is one of the most conspicuous characteristics that distinguish cancer cells from normal cells. Many studies suggest that several underlying mechanisms lead to the Warburg effect (increased aerobic glycolysis) during cancer development. Here, we explored how oroxylin A affected the glycolytic metabolism in cancer cells and the underlying mechanism involved in this process. Our data revealed that both oroxylin A and adriamycin could inhibit lactate generation and glucose uptake in HepG2 cells at mild concentrations, without causing robust cell apoptosis. Oroxylin A has exerted little influence on the oxygen consumption, whereas adriamycin decreased oxygen consumption in a concentration-dependent manner. Moreover, oroxylin A could increase protein and mRNA expression of TP53-induced glycolysis and apoptosis regulator (TIGAR) and synthesis of cytochrome c oxidase 2 (SCO2), which are the key metabolic modulators regulated by p53. Meanwhile adriamycin could increase protein and mRNA expression of TIGAR and SCO2, but decrease that of phosphoglycerate mutase (PGM). Oroxylin A and adriamycin also modulated the stability and activity of p53 through inducing phosphorylation of p53 at Ser15 and suppressing the expression of MDM2. Furthermore, p53 siRNA and p53 inhibitor assay in wild-type p53 HepG2 cells both revealed the key role of p53 in oroxylin A and adriamycin-mediated glycolytic metabolism regulation. Transfecting wt p53 plasmid to p53-deficient H1299 cells could inverse some of the metabolic characteristics regulated by oroxylin A. This study revealed a new aspect of glucose metabolism regulation of oroxylin A, which may contribute to its new anticancer mechanism.

Topics: Apoptosis; Apoptosis Regulatory Proteins; Biological Transport; Carcinoma, Hepatocellular; Carrier Proteins; Cell Line, Tumor; Cell Proliferation; Doxorubicin; Energy Metabolism; Flavonoids; Glucose; Glycolysis; Hep G2 Cells; Humans; Intracellular Signaling Peptides and Proteins; Lactic Acid; Liver Neoplasms; Mitochondrial Proteins; Molecular Chaperones; Oxidative Phosphorylation; Oxygen Consumption; Phosphoglycerate Mutase; Phosphoric Monoester Hydrolases; Phosphorylation; Proto-Oncogene Proteins c-mdm2; RNA Interference; RNA, Messenger; RNA, Small Interfering; Tumor Suppressor Protein p53

Oroxylin A, a naturally occurring monoflavonoid extracted from Scutellariae radix, shows effective anticancer activities and low toxicities both in vivo and in vitro in previous studies. In this study, we investigated whether the CAM-DR model of HepG2 cells showed resistance to cytotoxic agents compared with normally cultured HepG2 cells. Furthermore, after the treatment of Paclitaxel, less inhibitory effects and decreased apoptosis rate were detected in the model. Data also revealed increased expression of Integrinβ1 might be responsible for the resistance ability. Moreover, Integrinβ1-siRNA-transfected CAM-DR HepG2 cells exhibited more inhibitory effects and higher levels of apoptosis than the non-transfected CAM-DR cells. The data corroborated that Integrinβ1 played a significant role in CAM-DR. After the treatment of weakly-toxic concentrations of Oroxylin A, the apoptosis induced by Paclitaxel in the CAM-DR model increased dramatically. Western blot assay revealed Oroxylin A markedly down-regulated the expression of Integrinβ1 and the activity of related pathway. As a conclusion, Oroxylin A can reverse the resistance of CAM-DR via inhibition of Integrinβ1 and its related pathway. Oroxylin A may be a potential candidate of a CAM-DR reversal agent.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Blotting, Western; Carcinoma, Hepatocellular; Cell Adhesion; Dose-Response Relationship, Drug; Down-Regulation; Drug Resistance, Neoplasm; Flavonoids; Hep G2 Cells; Humans; Integrin beta1; Liver Neoplasms; Paclitaxel; Scutellaria baicalensis

Autophagy is a tightly-regulated catabolic process that involves the degradation of intracellular components via lysosomes. Although the pivotal role of autophagy in cell growth, development, and homeostasis has been well understood, its function in cancer prevention and intervention remains to be delineated. The aim of this study was to investigate the function and mechanism of autophagy induced by oroxylin A, a natural mono-flavonoid extracted from Scutellariae radix. We found for the first time that oroxylin A induced Beclin 1-mediated autophagy in human hepatocellular carcinoma HepG2 cells. Time-lapse video microscopy and western blotting studies showed that treatment of cells with 80 μM oroxylin A resulted in the conversion of water soluble MAP-LC3 (LC3-I) to the lipidated and autophagosome-associated form (LC3-II) after 12hours; then autophagosome-lysosome fusion and lysosome degradation after 24 hours was required in oroxylin A-mediated cell death. This induction was associated with the suppressing of PI3K-PTEN-Akt-mTOR signaling pathway by oroxylin A. Our results also showed that autophagy took place before noticeable apoptosis can be observed. It was further demonstrated that oroxylin A-triggered autophagy contributed to cell death using over-expression of autophagy-related gene (Atg5 and Atg7) and inhibition of autophagy by siBeclin 1 and 3-methyladenine (3-MA). In vivo study, oroxylin A inhibited xenograft tumor growth and induced obvious autophagy in tumors. Taken together, we conclude that oroxylin A exhibits autophagy-mediated antitumor activity in a dose and time-dependent manner in vivo and in vitro. These findings define and support a novel function of autophagy in promoting death of hepatocellular carcinoma cells.

Topics: Antineoplastic Agents; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Carcinoma, Hepatocellular; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Flavonoids; Hep G2 Cells; Humans; Liver Neoplasms; Membrane Proteins; Signal Transduction; Structure-Activity Relationship; TOR Serine-Threonine Kinases; Tumor Cells, Cultured

Oroxylin A is a flavonoid isolated from the root of Scutellaria baicalensis Georgi. Our previous work demonstrated that the anti-tumor activity of oroxylin A was mainly attributed to its apoptosis inducing effect in cells. The present study explores the exact molecular mechanism of oroxylin A-induced apoptosis in tumor cells. We showed that oroxylin A-induced apoptosis in HepG2 cells was achieved through mitochondrial pathway. We also investigated which mitochondrial channels, PTP or MAC or both, were involved in the permeabilization of the mitochondrial outer membrane after treatment with oroxylin A. The results showed that oroxylin A-induced apoptosis in a PTP-independent manner; therefore, we focused our attention on MAC. As Bax is an essential constituent of MAC in certain systems, we examined the activation, subcellular location, oligomeric structure of Bax in HepG2 cells treated with oroxylin A. Moreover, our results showed that overexpression of Bcl-2 inhibited oroxylin A-induced apoptosis. In summary, we have demonstrated that opening of MAC, but not PTP, played a key role in oroxylin A-induced activation of mitochondrial apoptotic pathway in HepG2 cells.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; bcl-2-Associated X Protein; Carcinoma, Hepatocellular; Cell Line, Tumor; Cyclosporine; Dimerization; Flavonoids; Humans; Ion Channels; Liver Neoplasms; Membrane Potential, Mitochondrial; Mitochondria, Liver; Mitochondrial Membrane Transport Proteins; Mitochondrial Membranes; Mitochondrial Permeability Transition Pore; Neoplasm Proteins; Protein Transport; Proto-Oncogene Proteins c-bcl-2; Recombinant Fusion Proteins; RNA Interference; RNA, Small Interfering