Tricetin suppresses the migration/invasion of human glioblastoma multiforme cells by inhibiting matrix metalloproteinase-2 through modulation of the expression and transcriptional activity of specificity protein 1

Tricetin protects against liver fibrosis through promoting autophagy and Nrf2 signaling in hepatic stellate cells

AIMS

The study aims to investigate the role and underlying mechanisms of tricetin in regulating hepatic stellate cells (HSCs) activation.

MAIN METHODS

We treated human hepatic stellate cells line LX-2 and freshly isolated primary mouse hepatic stellate cells (mHSCs) with tricetin, pharmacological inhibitors and siRNAs, western blot, immunofluorescence, quantitative PCR were used to evaluate the expression of fibrotic markers, autophagy levels and Nrf2 (nuclear factor E2-related factor 2) signaling.

KEY FINDINGS

Herein, we demonstrated that tricetin strongly attenuated the proliferation, migration, lipid droplets (LDs) loss and fibrotic markers Col 1a1 (type I α 1 collagen) and α-SMA (α-smooth muscle actin) expression in LX-2 cells. Moreover, tricetin time- and dose-dependently provoked autophagic formation in LX-2 cells. Autophagy inhibition by pharmacological intervention or genetic ATG5 (autophagy related 5) silencing facilitated tricetin-induced downregulation of profibrotic markers in LX-2 cells. Additionally, tricetin treatment reduced reactive oxygen species (ROS) accumulation, promoted Nrf2 signaling in LX-2 cells and pretreatment with ROS scavenger NAC partially reversed tricetin-induced autophagy and enhanced tricetin-mediated HSCs inactivation. Nrf2 silencing partially reversed tricetin-mediated inhibition of α-SMA expression. Finally, utilizing primary mouse hepatic stellate cells (mHSCs), we demonstrated that tricetin also induced autophagy activation, repressed TGF-β1-induced LDs loss and fibrotic marker expression and pretreatment with CQ further sensitized these effects.

SIGNIFICANCE

Our study indicates that tricetin's actions may represent an effective strategy to treat liver fibrosis and help identify novel therapeutic targets, especially in combination with autophagy inhibitors.

Tricetin suppresses the cell migration and BMP-6 expression through p38 signaling pathways in human retinal pigment epithelium cells

Proliferative vitreoretinopathy (PVR) is a visual-threatening disease, which cause from the migration of retinal pigment epithelium (RPE). Tricetin, a family of flavonoids, can inhibit the metastasis of several cancers. Herein, we aim to evaluate the possible effect of tricetin on inhibiting ARPE-19 cells migration. The Boyden chamber assay, wound healing assay, RNA sequencing, and Western blot analysis were applied in our experiment. The results revealed that tricetin inhibited the cell migration abilities of ARPE-19 cells. Moreover, using RNA sequencing technology, we revealed that tricetin repressed bone morphogenetic protein-6 (BMP-6) gene expressions in ARPE-19 cells. Overexpression of BMP-6 resulted in significant restoration of cell migration capabilities of tricetin-treated ARPE-19 cells. Furthermore, tricetin suppressed the phosphorylation of the p38 signaling pathway. Moreover, blocking the p38 pathway also inhibits BMP-6 expression and migration in the ARPE-19 cells. In conclusion, this study revealed that tricetin inhibits the ARPE-19 cell migration mainly via the suppression of BMP-6 expression and p38 signaling pathway.

Targeting extracellular matrix through phytochemicals: a promising approach of multi-step actions on the treatment and prevention of cancer

Extracellular matrix (ECM) plays a pivotal and dynamic role in the construction of tumor microenvironment (TME), becoming the focus in cancer research and treatment. Multiple cell signaling in ECM remodeling contribute to uncontrolled proliferation, metastasis, immune evasion and drug resistance of cancer. Targeting trilogy of ECM remodeling could be a new strategy during the early-, middle-, advanced-stages of cancer and overcoming drug resistance. Currently nearly 60% of the alternative anticancer drugs are derived from natural products or active ingredients or structural analogs isolated from plants. According to the characteristics of ECM, this manuscript proposes three phases of whole-process management of cancer, including prevention of cancer development in the early stage of cancer (Phase I); prevent the metastasis of tumor in the middle stage of cancer (Phase II); provide a novel method in the use of immunotherapy for advanced cancer (Phase III), and present novel insights on the contribution of natural products use as innovative strategies to exert anticancer effects by targeting components in ECM. Herein, we focus on trilogy of ECM remodeling and the interaction among ECM, cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs), and sort out the intervention effects of natural products on the ECM and related targets in the tumor progression, provide a reference for the development of new drugs against tumor metastasis and recurrence.

Tricetin Reduces Inflammation and Acinar Cell Injury in Cerulein-Induced Acute Pancreatitis: The Role of Oxidative Stress-Induced DNA Damage Signaling

Acute pancreatitis (AP) poses a worldwide challenge due to the growing incidence and its potentially life-threatening course and complications. Specific targeted therapies are not available, prompting the identification of new pathways and novel therapeutic approaches. Flavonoids comprise several groups of biologically active compounds with wide-ranging effects. The flavone compound, tricetin (TCT), has not yet been investigated in detail but sporadic reports indicate diverse biological activities. In the current study, we evaluated the potential protective effects of TCT in AP. TCT (30 μM) protected isolated primary murine acinar cells from the cytotoxic effects of cerulein, a cholecystokinin analog peptide. The protective effects of TCT were observed in a general viability assay (calcein ester hydrolysis), in an apoptosis assay (caspase activity), and in necrosis assays (propidium iodide uptake and lactate dehydrogenase release). The effects of TCT were not related to its potential antioxidant effects, as TCT did not protect against H₂O₂-induced acinar cell death despite possessing radical scavenging activity. Cerulein-induced expression of IL1β, IL6, and matrix metalloproteinase 2 and activation of nuclear factor-κB (NFκB) were reduced by 30 μM TCT. In vivo experiments confirmed the protective effect of TCT in a mouse model of cerulein-induced AP. TCT suppressed edema formation and apoptosis in the pancreas and reduced lipase and amylase levels in the serum. Moreover, TCT inhibited interleukin-1β (IL1β), interleukin-6 (IL6), and tumor necrosis factor-α (TNFα) expression in the pancreas and reduced the activation of the oxidative DNA damage sensor enzyme poly(ADP-ribose) polymerase-1 (PARP-1). Our data indicate that TCT can be a potential treatment option for AP.

The Inhibitory Effects of Terminalia catappa L. Extract on the Migration and Invasion of Human Glioblastoma Multiforme Cells

Glioblastoma multiforme (GBM) is one of the most aggressive and common types of brain tumor. Due to its high proliferation ability, a high lethality rate has been observed with this malignant glial tumor. Terminalia catappa L. (T. catappa) is currently known to have anti-inflammatory and anti-carcinogenesis effects. However, few studies have examined the mechanisms of the leaf extracts of T. catappa (TCE) on GBM cells. In the current study, we demonstrated that TCE can significantly inhibit the migration and invasion capabilities of GBM cell lines without showing biotoxic effects. Matrix metalloproteinases-2 (MMP-2) activity and protein expression were attenuated by reducing the p38 phosphorylation involved in the mitogen-activated protein kinase (MAPK) pathway. By treating with TCE and/or p38 inhibitor (SB203580), we confirmed that p38 MAPK is involved in the inhibition of cell migration. In conclusion, our results demonstrated that TCE inhibits human GBM cell migration and MMP-2 expression by regulating the p38 pathway. These results reveal that TCE contains potent therapeutic compounds which could be applied for treating GBM brain tumors.

Modulating the ERK1/2-MMP1 Axis through Corosolic Acid Inhibits Metastasis of Human Oral Squamous Cell Carcinoma Cells

Corosolic acid (CA; 2α-hydroxyursolic acid) is a natural pentacyclic triterpenoid with antioxidant, antitumour and antimetastatic activities against various tumour cells during tumourigenesis. However, CA’s antitumour effect and functional roles on human oral squamous cell carcinoma (OSCC) cells are utterly unknown. In this study, our results demonstrated that CA significantly exerted an inhibitory effect on matrix metalloproteinase (MMP)1 expression, cell migration and invasion without influencing cell growth or the cell cycle of human OSCC cells. The critical role of MMP1 was confirmed using the GEPIA database and showed that patients have a high expression of MMP1 and have a shorter overall survival rate, confirmed on the Kaplan–Meier curve assay. In the synergistic inhibitory analysis, CA and siMMP1 co-treatment showed a synergically inhibitory influence on MMP1 expression and invasion of human OSCC cells. The ERK1/2 pathway plays an essential role in mediating tumour progression. We found that CA significantly inhibits the phosphorylation of ERK1/2 dose-dependently. The ERK1/2 pathway played an essential role in the CA-mediated downregulation of MMP1 expression and in invasive motility in human OSCC cells. These findings first demonstrated the inhibitory effects of CA on OSCC cells’ progression through inhibition of the ERK1/2–MMP1 axis. Therefore, CA might represent a novel strategy for treating OSCC.

Dynein Light Chain Protein Tctex1: A Novel Prognostic Marker and Molecular Mediator in Glioblastoma

Simple Summary

Glioblastoma (GBM) remains one of the deadliest solid cancers, with only a dismal proportion of GBM patients achieving 5-year survival. Thus, it is critical to identify molecular mechanisms that could be targeted by novel therapeutic approaches in this tumor type. Our study identified Tctex1/DYNLT1 as an independent prognostic marker for the overall survival of GBM patients. Importantly, Tctex1 promoted the aggressiveness of GBM cells by enhancing tumor proliferation and invasion. These effects of Tctex1 appeared to be modulated via phosphorylation of retinoblastoma protein (RB) and the release of matrix metalloprotease 2 (MMP2), respectively. As Tctex1 can potentially be inhibited in vivo, our study provides a rationale for novel, individualized therapeutic strategies in GBM patients.

Abstract

The purpose of this study was to determine the role of Tctex1 (DYNLT1, dynein light chain-1) in the pathophysiology of glioblastoma (GBM). To this end, we performed immunohistochemical analyses on tissues from GBM patients (n = 202). Tctex1 was additionally overexpressed in two different GBM cell lines, which were then evaluated in regard to their proliferative and invasive properties. We found that Tctex1 levels were significantly higher in GBM compared to healthy adjacent brain tissues. Furthermore, high Tctex1 expression was significantly associated with the short overall- (p = 0.002, log-rank) and progression-free (p = 0.028, log-rank) survival of GBM patients and was an independent predictor of poor overall survival in multivariate Cox-regression models. In vitro, Tctex1 promoted the metabolic activity, anchorage-independent growth and proliferation of GBM cells. This phenomenon was previously shown to occur via the phosphorylation of retinoblastoma protein (phospho-RB). Here, we found a direct and significant correlation between the levels of Tctex1 and phospho-RB (Ser807/801) in tissues from GBM patients (p = 0.007, Rho = 0.284, Spearman’s rank). Finally, Tctex1 enhanced the invasiveness of GBM cells and the release of pro-invasive matrix metalloprotease 2 (MMP2). These findings indicate that Tctex1 promotes GBM progression and therefore might be a useful therapeutic target in this type of cancer.

Propolis Extract Regulate microRNA Expression in Glioblastoma and Brain Cancer Stem Cells

BACKGROUND

Grade IV gliomas are classified as glioblastoma (GBM), which is the most malignant brain cancer type. Various genetic and epigenetic mechanisms play a role in the initiation and progression of GBM. MicroRNAs (miRNAs) are small, non-coding RNA molecules that are the main epigenetic regulatory RNA class. They play variable roles in both physiological and pathological conditions, including GBM pathogenesis, by regulating expression levels of the target genes. Brain cancer stem cells (BCSCs) are subpopulations of brain cancer mass that are responsible for poor prognosis, including therapy resistance and relapse. Epigenetic regulation mediated by miRNAs is also a critical component of BCSC self-renewal and differentiation properties. Propolis is a resinous substance that is collected by honey bees from various plant sources. The flavonoids content of propolis varies, depending on the region collected andthe extraction method. Although the effects of propolis that have been collected from different sources on the miRNA expression levels in the glioblastoma cells have been shown, the effects on the BCSCs are not known yet.

OBJECTIVE

The aim of this study is to evaluate the effects of Aydın, a city in western Turkey, propolis, on miRNA expression levels of BCSCs and GBM cells.

METHODS

Aydin propolis was dissolved in 60% ethanol, and after evaporation, distilled water was added to prepare the propolis stock solution. The flavonoids content of the Aydin propolis was determined by MS Q-TOF analysis. Commercially obtained U87MG, GBM cell line, and BCSCs were used as in vitro brain cancer models. The cytotoxic and apoptotic effects of Aydın propolis were determined via WST-1 assay and Annexin V test, respectively. The miRNA expression profile was investigated via the real-time qRT-PCR method, and fold changes were calculated by using the 2-^∆∆Ct method compared to untreated control cells. The miRNA-mRNA-pathway interactions, including significantly altered miRNAs, were determined using different bioinformatics tools and databases.

RESULTS

Quercetin 3-methyl ether was determined as the major component of the Aydin propolis. Aydin propolis did not show significant cytotoxic and apoptotic effects on both GBM and BCSCs up to 2mg/ml concentration. Aydin propolis treatment decreased the expression of nine and five miRNAs in the U87MG 2.13 to 5.65 folds and BCSCs 2.02 to 12.29 folds, respectively. Moreover, 10 miRNAs 2.22 to 10.56 folds were upregulated in propolis treated GBM cells compared to the control group, significantly (p<0.05). In the study, the potential roles of two new miRNAs, whose regulations in glioma were not previously defined, were identified. One of these miR-30d-5p, a novel potential oncomiR in GBM was 2.46 folds downregulated in Aydin propolis treated GBM cells. The other one is miR-335-5p which is a potential tumor suppressor miR in GBM, was 5.66 folds upregulated in Aydin propolis treated GBM cells. FOXO pathway and its upstream and downstream regulators and critically neuronal developmental regulators NOTCH and WNT pathways were determined as the most deregulated pathways in Aydin propolis treated cells.

CONCLUSION

The determination of the anti-cancer effect of Aydın propolis on the miRNA expression of GBM, especially on cancer stem cells, may contribute to the elucidation of brain cancer genetics by supporting further analyses.

Tricetin Suppresses Migration and Presenilin-1 Expression of Nasopharyngeal Carcinoma through Akt/GSK-3β Pathway

Lymph node migration results in poor prognoses for nasopharyngeal carcinoma (NPC) patients. Tricetin, a flavonoid derivative, regulates tumorigenesis activity through its antiproliferative and antimetastatic properties. However, the molecular mechanism of tricetin affecting the migration and invasion of NPC cells remains poorly understood. In this paper, we examined the antimetastatic properties of tricetin in human NPC cells. Our results demonstrated that tricetin at noncytotoxic concentrations (0-80 3M) noticeably reduced the migration and invasion of NPC cells (HONE-1, NPC-39, and NPC-BM). Moreover, tricetin suppressed the indicative protease, presenilin-1 (PS-1), as indicated by protease array. PS-1 was transcriptionally inhibited via the Akt signaling pathway but not mitogen-activated protein kinase pathways, such as the JNK, p38, and ERK1/2 pathways. In addition to upregulating GSK-3[Formula: see text] phosphorylation through Akt suppression, tricetin may downregulate the activity of PS-1. Overall, our study provides new insight into the role of tricetin-induced molecular regulation in the suppression of NPC metastasis and suggests that tricetin has prospective therapeutic applications for patients with NPC.

Antimetastatic Effects of Sesamin on Human Head and Neck Squamous Cell Carcinoma through Regulation of Matrix Metalloproteinase-2

Background: Sesamin is a lignin present in sesame oil from the bark of Zanthoxylum spp. Sesamin reportedly has anticarcinogenic potential and exerts anti-inflammatory effects on several tumors. Hypothesis/Purpose: However, the effect of sesamin on metastatic progression in human head and neck squamous carcinoma (HNSCC) remains unknown in vitro and in vivo; hence, we investigated the effect of sesamin on HNSCC cells in vitro. Methods and Results: Sesamin-treated human oral cancer cell lines FaDu, HSC-3, and Ca9-22 were subjected to a wound-healing assay. Furthermore, Western blotting was performed to assess the effect of sesamin on the expression levels of matrix metalloproteinase (MMP)-2 and proteins of the MAPK signaling pathway, including p-ERK1/2, P-p38, and p-JNK1/2. In addition, we investigated the association between MMP-2 expression and the MAPK pathway in sesamin-treated oral cancer cells. Sesamin inhibited cell migration and invasion in FaDu, Ca9-22, and HSC-3 cells and suppressed MMP-2 at noncytotoxic concentrations (0 to 40 μM). Furthermore, sesamin significantly reduced p38 MAPK and JNK phosphorylation in a dose-dependent manner in FaDu and HSC-3 cells. Conclusions: These results indicate that sesamin suppresses the migration and invasion of HNSCC cells by regulating MMP-2 and is thus a potential antimetastatic agent for treating HNSCC.

Gold nanoparticles synthesised by flavonoid tricetin as a potential antibacterial nanomedicine to treat respiratory infections causing opportunistic bacterial pathogens

In this study, flavonoid tricetin was used as a reducing and capping agent for the synthesis of gold nanoparticles (AuNPs). Further, the antibacterial efficacy of the synthesised AuNPs was evaluated against the opportunistic bacterial pathogens that cause respiratory infections. The optimum levels for the synthesis of AuNPs were found to be pH 8, temperature 30 °C, tricetin 125 μM and chloroauric acid 250 μM. The tricetin synthesised AuNPs exhibited in spherical shape with an average size of 12 nm. FT-IR results confirmed that the hydroxyl (OH) and carbonyl (CO) groups of tricetin were mainly participated in the synthesis of AuNPs. The opportunistic bacterial pathogens isolated from immunocompromised patients suffering with different respiratory infections were identified as Staphylococcus aureus, Enterobacter xiangfangensis, Bacillus licheniformis, Escherichia fergusonii, Acinetobacter pittii, Pseudomonas aeruginosa, Aeromonas enteropelogenes and Proteus mirabilis. The antibacterial studies confirmed the broad-spectrum antibacterial activity of AuNPs against the tested Gram-positive and Gram-negative bacteria. The synthesised AuNPs showed high biocompatibility on primary normal human dermal fibroblast (NHDF-c) cells up to 50 μM mL^-1. Best of our knowledge, this is the first report on the synthesis of AuNPs using tricetin, which may be a potential antibacterial nanomedicine to treat bacterial infections.

Geraniin inhibits oral cancer cell migration by suppressing matrix metalloproteinase-2 activation through the FAK/Src and ERK pathways

Geraniin has been reported to have numerous biological activities, including antiviral, antihypertensive, antihyperglycaemic, liver protective, antidiabetic, and apoptotic activities. However, the anti-migration effects of geraniin on oral cancer remain elusive. In this study, we revealed the potential antitumor mechanisms of geraniin through the inhibition of the migration and invasion of human oral cancer cell lines SCC-9 and SCC-14. The results of gelatin zymography and Western blot assays revealed that geraniin significantly reduced the activity and expression of matrix metalloproteinase-2 (MMP-2) of oral cancer cells in a concentration-dependent manner. Furthermore, geraniin potently suppressed the phosphorylation of focal adhesion kinase (FAK), Src, and extracellular signal-regulated kinase (ERK)1/2 but did not affect the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase 1/2. Moreover, blocking the MAPK/ERK1/2 pathway significantly enhanced the anti-migration ability of geraniin in oral cancer cells. In conclusion, we demonstrated that geraniin inhibits the motility of SCC-9 and SCC-14 cells in vitro through a molecular mechanism that involves the attenuation of MMP-2 expression and activity mediated by decreased FAK/Src and ERK1/2 pathways.

Tricetin Protects Rat Chondrocytes against IL-1β-Induced Inflammation and Apoptosis

Tricetin is a well-studied flavonoid with a wide range of pharmacological activities in cancer and inflammation. However, the ability of tricetin to ameliorate the inflammation that occurs in osteoarthritis (OA) has not been determined. This study explored the effects of tricetin on interleukin- (IL-) 1β-induced rat chondrocytes. Chondrocytes harvested from rat cartilage were incubated in vitro with tricetin in the presence of IL-1β. The expression of matrix metalloproteinase- (MMP-) 1, MMP-3, MMP-13, nitric oxide (NO), prostaglandin E2 (PGE2), Bax, and Bcl-2 was evaluated by real-time-PCR, ELISA, Griess reaction, and western blotting. Caspase-3 activity in chondrocytes was determined using a caspase-3 activity assay and MAPK pathway activity by western blotting. Tricetin decreased the expression of MMP-1, MMP-3, and MMP-13 at both the gene and protein level in IL-1β-induced rat chondrocytes. It also inhibited IL-1β-induced NO and PGE2 production, by modulating inducible NO synthase and cyclooxygenase 2 gene expression. An antiapoptotic role of tricetin involving the Bax/Bcl-2/caspase-3 pathway was also determined. The chondroprotective effect of tricetin was shown to be partly related to the suppression of the MAPK signaling pathway. The results of this study demonstrate the chondroprotective role of tricetin, based on its anticatabolic, anti-inflammatory, and antiapoptotic effects in chondrocytes. The therapeutic potential of tricetin in OA patients should be explored in future studies.

Licochalcone A inhibits the invasive potential of human glioma cells by targeting the MEK/ERK and ADAM9 signaling pathways

Licochalcone A (LicA) has been reported to possess antitumor properties. However, its effect on human glioma cells remains unknown. In this study, we observed that LicA significantly suppressed the ADAM9 expression and the migration and invasion activities of human glioma cells (M059K, U-251 MG, and GBM8901) and exhibited no cell cytotoxicity. The human proteinase antibody array and immunoblot analysis indicated that the LicA treatment inhibited the expression of ADAM9 protein in human glioma cells. Recombinant human ADAM-9 (Rh-ADAM9) treatment significantly reversed the LicA-induced reduction in the ADAM9 level and the migration and invasion activities of human glioma cells. Additionally, the phosphorylation/activation of the mitogen-activated protein kinase kinase (MEK)-extracellularly responsive kinases (ERK) signaling pathway was significantly suppressed in LicA-treated human glioma cells. Cotreatment with LicA and PD98059 synergistically inhibited the ADAM9 expression, cell migration, and cell invasion, which suggested that the MEK-ERK signaling pathway was involved in the LicA-induced inhibition of the ADAM9 expression and the invasion activity of human glioma cells. These findings are the first evidence of LicA's anti-invasive properties against human glioma cells.

Effects of dihydromyricetin on ARPE-19 cell migration through regulating matrix metalloproteinase-2 expression

Dihydromyricetin (DHM), a flavanonol compound in Ampelopsis grossedentata, possesses several biological activities. However, the molecular mechanism underlying the effects of DHM on human proliferative vitreoretinopathy (PVR) remains unclear. We explored the effects of DHM on cell migration and the metastasis-promoting proteins in human retinal pigment epithelial (RPE) cells (ARPE-19 cells). Our results revealed that DHM attenuated ARPE-19 cell invasion and migration by reducing matrix metalloproteinase-2 (MMP-2) expression. Furthermore, a Western blot analysis revealed that DHM significantly reduced levels of phosphorylated c-Jun N-terminal kinase 1/2, but not those of extracellular signal-regulated kinase 1/2 and p38. In conclusion, our findings shown that DHM inhibits human RPE cell migration through the inhibition of MMP-2 expression; therefore, DHM may have potential therapeutic value in treating PVR as adjuvant therapy.

Antimetastatic effects of Eclipta prostrata extract on oral cancer cells

Eclipta prostrata, a traditional Chinese medication, has been used for the treatment of several diseases. However, the molecular mechanism underlying the effects of Eclipta prostrata extracts (EPE) on human oral cancer cell metastasis remains unclear. We thus examined the effects of EPE on metastasis promoting proteins in oral cancer. Our results revealed that the EPE attenuated SCC-9, HSC-3, and TW2.6 cell migration and invasiveness by reducing matrix metalloproteinase (MMP)-2 enzyme activities. In addition, Western blot analysis revealed that EPE significantly reduced the levels of phosphorylated extracellular signal-regulated kinase 1/2 (ERK 1/2) but not those of c-Jun N-terminal kinase (JNK) 1/2 and p38. In conclusion, we found that EPE could inhibit oral cancer metastasis through the inhibition of MMP-2 expression. Therefore, EPE may be used to prevent the metastasis of oral cancer, and has the potential to be applied to cancer treatment.

Melatonin inhibits TPA-induced oral cancer cell migration by suppressing matrix metalloproteinase-9 activation through the histone acetylation

Melatonin exerts antimetastatic effects on liver and breast cancer and also inhibits matrix metalloproteinase (MMP) activity. However, the detailed impacts and underlying mechanisms of melatonin on oral cancer cell metastasis are still unclear. This study showed that melatonin attenuated the 12-O-tetradecanoylphorbol-13-acetate-induced migration of oral cancer cell lines, HSC-3 and OECM-1. Zymography, quantitative real-time PCR, and Western blotting analyses revealed that melatonin lessened MMP-9 enzyme activity as well as the expression of MMP-9 mRNA and protein. Furthermore, melatonin suppressed the phosphorylation of the ERK1/2 signalling pathway, which dampened MMP-9 gene transcription by affecting the expression of transcriptional coactivators, such as CREB-binding protein (CREBBP) and E1A binding protein p300 (EP300), and decreasing histone acetylation in HSC-3 and OECM-1 cells. Examinations on clinical samples exhibited that MMP-9, CREBBP, and EP300 were significantly increased in oral cancer tissues. Moreover, the relative level of CREBBP was positively correlated with the expression of MMP-9 and EP300. In conclusion, we demonstrated that melatonin inhibits the motility of HSC-3 and OECM-1 cells in vitro through a molecular mechanism that involves attenuation of MMP-9 expression and activity mediated by decreased histone acetylation.

Andrographolide suppresses the migratory ability of human glioblastoma multiforme cells by targeting ERK1/2-mediated matrix metalloproteinase-2 expression

Glioblastoma multiforme (GBM) can be a fatal tumor because of difficulties in treating the related metastasis. Andrographolide is the bioactive component of the Andrographis paniculata. Andrographolide possesses the anti-inflammatory activity and inhibits the growth of various cancers; however, its effect on GBM cancer motility remains largely unknown. In this study, we examined the antimetastatic properties of andrographolide in human GBM cells. Our results revealed that andrographolide inhibited the invasion and migration abilities of GBM8401 and U251 cells. Furthermore, andrographolide inhibited matrix metalloproteinase (MMP)-2 activity and expression. Real-time PCR and promoter activity assays indicated that andrographolide inhibited MMP-2 expression at the transcriptional level. Such inhibitory effects were associated with the suppression of CREB DNA-binding activity and CREB expression. Mechanistically, andrographolide inhibited the cell motility of GBM8401 cells through the extracellular-regulated kinase (ERK) 1/2 pathway, and the blocking of the ERK 1/2 pathway could reverse MMP-2-mediated cell motility. In conclusion, CREB is a crucial target of andrographolide for suppressing MMP-2-mediated cell motility in GBM cells. Therefore, a combination of andrographolide and an ERK inhibitor might be a good strategy for preventing GBM metastasis.

Tricetin suppresses human oral cancer cell migration by reducing matrix metalloproteinase-9 expression through the mitogen-activated protein kinase signaling pathway

Tricetin is a flavonoid derivative and a potent anti-inflammatory and anticancer agent. However, the molecular mechanism underlying the effects of tricetin on human oral cancer cell migration remains unclear. The cell migration and invasion abilities of three oral cancer cell lines (SCC-9, HSC-3, and OECM-1) were analyzed using Boyden chamber migration assays. Our results demonstrated that tricetin attenuates 12-O-tetradecanoylphorbol-13-acetate-induced SCC-9, HSC-3, and OECM-1 cell invasiveness and migration by reducing matrix metalloproteinase (MMP)-9 enzyme activity. The reverse transcription polymerase chain reaction and luciferase reporter assay revealed that tricetin downregulates the mRNA expression and promoter activity of MMP-9. In addition, Western blot analysis revealed that tricetin significantly reduced the levels of phosphorylated c-Jun N-terminal kinase (JNK) 1/2 and p38 levels but not those of extracellular signal-regulated kinase 1/2. In conclusion, this study demonstrated that tricetin suppresses MMP-9 enzymatic activity by downregulating the p38/JNK1/2 pathway and might be a beneficial chemopreventive agent.

Antimetastatic effects of Rheum palmatum L. extract on oral cancer cells

Rheum palmatum L., a traditional Chinese medication, has been used for the treatment of various disorders. However, the detailed impacts and underlying mechanisms of R. palmatum L. extracts (RLEs) on human oral cancer cell metastasis are still unclear. Here, we tested the hypothesis that an RLE has antimetastatic effects on SCC-9 and SAS human oral cancer cells. Gelatin zymography, Western blot, real-time polymerase chain reaction, and luciferase assay were used to explore the underlying mechanisms involved in the antimetastatic effects on oral cancer cells. Our results revealed that the RLE (up to 20 μg/mL, without cytotoxicity) attenuated SCC-9 and SAS cell motility, invasiveness, and migration by reducing matrix metalloproteinase (MMP)-2 enzyme activities. Western blot analysis of the MAPK signaling pathway indicated that the RLE significantly decreased phosphorylated ERK1/2 levels but not p38 and JNK levels. In conclusion, RLEs exhibit antimetastatic activity against oral cancer cells through the transcriptional repression of MMP-2 via the Erk1/2 signaling pathways. Thus, RLEs may be potentially useful as antimetastatic agents for oral cancer chemotherapy.

Tricetin inhibits human osteosarcoma cells metastasis by transcriptionally repressing MMP-9 via p38 and Akt pathways

Tricetin, a dietary flavonoid, has cytostatic properties and anti-metastasis activities in various cancer cells. However, the detailed impacts and underlying mechanisms of tricetin on human osteosarcoma cell metastasis are still unclear. Here, the hypothesis that tricetin possesses the anti-metastatic effects on human osteosarcoma cells was tested. The effects of tricetin on cell viability, motility, migration, and invasion in human osteosarcoma U2OS and HOS cells were investigated. Gelatin zymography, western blotting, polymerase chain reaction (PCR), and the luciferase assay were used to further explore the underlying mechanisms involved in anti-metastatic effects in U2OS cells. Their results showed that Tricetin, up to 80 μM without cytotoxicity, attenuated U2OS and HOS cells motility, invasiveness, and migration by reducing matrix metalloproteinase (MMP)-9 enzyme activities. In U2OS cells, tricetin decreased MMP-9 protein and mRNA expressions, which was confirmed by real-time PCR. Next, tricetin reduced phosphorylation of p38 and Akt, but no effect on phosphorylation of ERK1/2 and JNK. In conclusion, tricetin possesses the anti-metastatic activity of osteosarcoma cells by transcriptionally repressing MMP-9 via p38 and Akt signaling pathways. This may be potentially useful as anti-metastatic agents for osteosarcoma chemotherapy.

Tricetin Induces Apoptosis of Human Leukemic HL-60 Cells through a Reactive Oxygen Species-Mediated c-Jun N-Terminal Kinase Activation Pathway

Tricetin is a dietary flavonoid with cytostatic properties and antimetastatic activities in various solid tumors. The anticancer effect of tricetin in nonsolid tumors remains unclear. Herein, the molecular mechanisms by which tricetin exerts its anticancer effects on acute myeloid leukemia (AML) cells were investigated. Results showed that tricetin inhibited cell viability in various types of AML cell lines. Tricetin induced morphological features of apoptosis such as chromatin condensation and phosphatidylserine (PS) externalization, and significantly activated proapoptotic signaling including caspase-8, -9, and -3 activation and poly(ADP-ribose) polymerase (PARP) cleavage in HL-60 AML cells. Of note, tricetin-induced cell growth inhibition was dramatically reversed by a pan caspase and caspase-8- and -9-specific inhibitors, suggesting that this compound mainly acts through a caspase-dependent pathway. Moreover, treatment of HL-60 cells with tricetin induced sustained activation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), and inhibition of ERK and JNK by their specific inhibitors respectively promoted and abolished tricetin-induced cell apoptosis. Dichlorofluorescein (DCF) staining showed that intracellular reactive oxygen species (ROS) levels were higher in tricetin-treated HL-60 cells compared to the control group. Moreover, an ROS scavenger, N-acetylcysteine (NAC), reversed tricetin-induced JNK activation and subsequent cell apoptosis. In conclusion, our results indicated that tricetin induced cell death of leukemic HL-60 cells through induction of intracellular oxidative stress following activation of a JNK-mediated apoptosis pathway. A combination of tricetin and an ERK inhibitor may be a better strategy to enhance the anticancer activities of tricetin in AML.