Licochalcone A induces endoplasmic reticulum stress-mediated apoptosis of endometrial cancer cells via upregulation of GRP78 expression.

Licochalcone A (LicA), a natural compound extracted from licorice root, has been shown to exert a variety of anticancer activities. Whether LicA has such effects on endometrial cancer (EMC) is unclear. This study aims to investigate the antitumor effects of LicA on EMC. Our results show that LicA significantly reduced the viability and induced apoptosis of EMC cells and EMC-7 cells from EMC patients. LicA was also found to induce endoplasmic reticulum (ER) stress, leading to increased expression of ER-related proteins (GRP78/PERK/IRE1α/CHOP) in EMC cell lines. Suppression of GRP78 expression in human EMC cells treated with LicA significantly attenuated the effects of LicA, resulting in reduced ER-stress mediated cell apoptosis and decreased expression of ER- and apoptosis-related proteins. Our findings demonstrate that LicA induces apoptosis in EMC cells through the GRP78-mediated ER-stress pathway, emphasizing the potential of LicA as an anticancer therapy for EMC.

Induction of immunogenic cell death effect of licoricidin in cervical cancer cells by enhancing endoplasmic reticulum stress-mediated high mobility group box 1 expression.

Licoricidin (LCD) is an activity compound of the roots of Glycyrrhiza uralensis, which has therapeutic efficacy, including anti-virus, anti-cancer, and enhanced immunity in Traditional Chinese Medicine. Herein, this study aimed to clarify the effect of LCD on cervical cancer cells. In the present study, we found that LCD significantly inhibited cell viability via inducing cell apoptosis and companies with cleaved-PARP protein expression and caspase-3/-9 activity. Cell viability was markedly reversed these effects by pan-caspase inhibitor Z-VAD-FMK treatment. Furthermore, we showed that LCD-induced ER (endoplasmic reticulum) stress triggers upregulating the protein level of GRP78 (Bip), CHOP, and IRE1α, and subsequently confirmed the mRNA level by quantitative real-time polymerase chain reaction. In addition, LCD exhibited the release of danger-associated molecular patterns from cervical cancer cells, such as the release of high-mobility group box 1 (HMGB1), secretion of ATP, and exposure of calreticulin (CRT) on the cell surface, which led to immunogenic cell death (ICD). These results provide a novel foundation that LCD induces ICD via triggering ER stress in human cervical cancer cells. LCD might be an ICD inducer of immunotherapy in progressive cervical cancer.

Adversarial Patch Attacks on Deep-Learning-Based Face Recognition Systems Using Generative Adversarial Networks.

Deep learning technology has developed rapidly in recent years and has been successfully applied in many fields, including face recognition. Face recognition is used in many scenarios nowadays, including security control systems, access control management, health and safety management, employee attendance monitoring, automatic border control, and face scan payment. However, deep learning models are vulnerable to adversarial attacks conducted by perturbing probe images to generate adversarial examples, or using adversarial patches to generate well-designed perturbations in specific regions of the image. Most previous studies on adversarial attacks assume that the attacker hacks into the system and knows the architecture and parameters behind the deep learning model. In other words, the attacked model is a white box. However, this scenario is unrepresentative of most real-world adversarial attacks. Consequently, the present study assumes the face recognition system to be a black box, over which the attacker has no control. A Generative Adversarial Network method is proposed for generating adversarial patches to carry out dodging and impersonation attacks on the targeted face recognition system. The experimental results show that the proposed method yields a higher attack success rate than previous works.

Praeruptorin A reduces metastasis of human hepatocellular carcinoma cells by targeting ERK/MMP1 signaling pathway.

Praeruptorin A (PA) is one of the active ingredients found in the dried root of Peucedanum praeruptorum Dunn, has been reported to possess anticancer effects against various types of cancer. However, the effect of PA on human hepatocellular carcinoma (HCC) remains uncleared. In this study, our results indicated that PA did not induce cytotoxicity or alter cell cycle distribution in human HCC cells (Huh-7, SK-Hep-1, and PLC/PRF/5 cells). Instead, PA inhibited the migration and invasion of human HCC cells while downregulating the expression of matrix metalloproteinase-1 (MMP1) and activating the extracellular signal-regulated kinase (ERK) signaling pathways. Furthermore, blocking the ERK signaling pathway through siERK restored the expression of MMP1 and the invasive ability of PA-treated HCC cells. In conclusion, our results demonstrate the antimetastatic activity of PA against human HCC cells, supporting its potential as a therapeutic agent of HCC treatments.

α-Mangostin attenuates stemness and enhances cisplatin-induced cell death in cervical cancer stem-like cells through induction of mitochondrial-mediated apoptosis.

Cancer stem cells (CSCs) exhibit specific characteristics including decontrolled self-renewal, tumor-initiating, promoting, and metastatic potential, abnormal stemness signaling, and chemotherapy resistance. Thus, targeting CSC is becoming an emerging cancer treatment. α-Mangostin has been shown to have potent and multiple anticancer activities. Accordingly, we hypothesized that α-mangostin may diminish the stemness and proliferation of CSC-like cervical cancer cells. In our results, comparing to the parent cells, CSC-like SiHa and HeLa cells highly expressed CSC marker Sox2, Oct4, Nanog, CK-17, and CD49f. α-Mangostin significantly reduced the cell viability, sphere-forming ability, and expression of the CSC stemness makers of CSC-like cervical cancer cells. Further investigation showed that α-mangostin induced mitochondrial depolarization and mitochondrial apoptosis signaling, including upregulation of Bax, downregulation of Mcl-1 and Bcl-2, and activation of caspase-9/3. Moreover, α-mangostin synergically enhanced the cytotoxicity of cisplatin on CSC-like SiHa cells by promoting mitochondrial apoptosis and inhibiting the expression of CSC markers. Consistent with in vitro findings, in vivo tumor growth assay revealed that α-mangostin administration significantly inhibited the growth of inoculated CSC-like SiHa cells and synergically enhanced the antitumor effect of cisplatin. Our findings indicate that α-mangostin can reduce the stemness and proliferation of CSC-like SiHa and HeLa cells and promote the cytotoxicity of cisplatin, which may attribute to the mitochondrial apoptosis activation. Thus, it suggests that α-mangostin may have clinical potential to improve chemotherapy for cervical cancer by targeting cervical CSC.

ß-Mangostin inhibits the metastatic power of cervical cancer cells attributing to suppression of JNK2/AP-1/Snail cascade.

ß-Mangostin is a natural mangostin with potent anticancer activity against various cancers. In this study, we further explored the anticancer activity of ß-mangostin on cervical cancer cells. ß-Mangostin did not affect cell viability and cell cycle distribution in HeLa and SiHa cells; however, it dose-dependently inhibited the migration and invasion of both the human cervical cancer cell lines. In addition, we observed that ß-mangostin suppressed the expression of integrin αV and ß3 and the downstream focal adhesion kinase/Src signaling. We also found that Snail was involved in the ß-mangostin inhibited cell migration and invasion of HeLa cell. Then, our findings showed that ß-mangostin reduced both nuclear translocation and messenger RNA expression of AP-1 and demonstrated that AP-1 could target to the Snail promoter and induce Snail expression. Kinase cascade analysis and reporter assay showed that JNK2 was involved in the inhibition of AP-1/Snail axis by ß-mangostin in HeLa cells. These results indicate that ß-mangostin can inhibit the mobility and invasiveness of cervical cancer cells, which may attribute to the suppression of both integrin/Src signaling and JNK2-mediated AP-1/Snail axis. This suggests that ß-mangostin has potential antimetastatic potential against cervical cancer cells.

Melatonin attenuates epidermal growth factor-induced cathepsin S expression in ARPE-19 cells: Implications for proliferative vitreoretinopathy.

Abnormal proliferation and motility of retinal pigment epithelial cells leads to proliferative vitreoretinopathy (PVR). Melatonin is a known effective antitumour and anti-invasive agent, but whether it affects the formation and underlying mechanisms of PVR remains unclear. In this study, the results of the MTT assay, colony formation and propidium iodide (PI) staining with flow cytometry revealed that melatonin dose dependently inhibited epidermal growth factor (EGF)-induced proliferation of human ARPE-19 cells. Furthermore, melatonin reduced EGF-induced motility by suppressing cathepsin S (CTSS) expression. Pretreatment with ZFL (a CTSS inhibitor) or overexpression of CTSS (pCMV-CTSS) significantly inhibited EGF-induced cell motility when combined with melatonin. Epidermal growth factor induced the phosphorylation of AKT(S473)/mTOR (S2448) and transcription factor (c-Jun/Sp1) signaling pathways. Pretreatment of LY294002 (a PI3K inhibitor) or rapamycin (an mTOR inhibitor) markedly reduced EGF-induced motility and p-AKT/p-mTOR/c-Jun/Sp1 expression when combined with melatonin. Taken together, these data indicate that melatonin inhibited EGF-induced proliferation and motility of human ARPE-19 cells by activating the AKT/mTOR pathway, which is dependent on CTSS modulation of c-Jun/Sp1 signalling. Melatonin may be a promising therapeutic drug against PVR.

Crystal structure of dimeric human PNPase reveals why disease-linked mutants suffer from low RNA import and degradation activities.

Human polynucleotide phosphorylase (PNPase) is an evolutionarily conserved 3'-to-5' exoribonuclease principally located in mitochondria where it is responsible for RNA turnover and import. Mutations in PNPase impair structured RNA transport into mitochondria, resulting in mitochondrial dysfunction and disease. PNPase is a trimeric protein with a doughnut-shaped structure hosting a central channel for single-stranded RNA binding and degradation. Here, we show that the disease-linked human PNPase mutants, Q387R and E475G, form dimers, not trimers, and have significantly lower RNA binding and degradation activities compared to wild-type trimeric PNPase. Moreover, S1 domain-truncated PNPase binds single-stranded RNA but not the stem-loop signature motif of imported structured RNA, suggesting that the S1 domain is responsible for binding structured RNAs. We further determined the crystal structure of dimeric PNPase at a resolution of 2.8 Å and, combined with small-angle X-ray scattering, show that the RNA-binding K homology and S1 domains are relatively inaccessible in the dimeric assembly. Taken together, these results show that mutations at the interface of the trimeric PNPase tend to produce a dimeric protein with destructive RNA-binding surfaces, thus impairing both of its RNA import and degradation activities and leading to mitochondria disorders.

Praeruptorin B Mitigates the Metastatic Ability of Human Renal Carcinoma Cells through Targeting CTSC and CTSV Expression.

Renal cell carcinoma (RCC) is the most common adult kidney cancer, and accounts for 85% of all cases of kidney cancers worldwide. Praeruptorin B (Pra-B) is a bioactive constituent of Peucedanum praeruptorum Dunn and exhibits several pharmacological activities, including potent antitumor effects. However, the anti-RCC effects of Pra-B and their underlying mechanisms are unclear; therefore, we explored the effects of Pra-B on RCC cells in this study. We found that Pra-B nonsignificantly influenced the cell viability of human RCC cell lines 786-O and ACHN at a dose of less than 30 µM for 24 h treatment. Further study revealed that Pra-B potently inhibited the migration and invasion of 786-O and ACHN cells, as well as downregulated the mRNA and protein expression of cathepsin C (CTSC) and cathepsin V (CTSV) of 786-O and ACHN cells. Mechanistically, Pra-B also reduced the protein levels of phospho (p)-epidermal growth factor receptor (EGFR), p-mitogen-activated protein kinase kinase (MEK), and p-extracellular signal-regulated kinases (ERK) in RCC cells. In addition, Pra-B treatment inhibited the effect of EGF on the upregulation of EGFR-MEK-ERK, CTSC and CTSV expression, cellular migration, and invasion of 786-O cells. Our findings are the first to demonstrate that Pra-B can reduce the migration and invasion ability of human RCC cells through suppressing the EGFR-MEK-ERK signaling pathway and subsequently downregulating CTSC and CTSV. This evidence suggests that Pra-B can be developed as an effective antimetastatic agent for the treatment of RCC.

Silencing PROK2 Inhibits Invasion of Human Cervical Cancer Cells by Targeting MMP15 Expression.

Cervical cancer is the second most frequent type of gynecologic cancer worldwide. Prokineticin 2 (PROK2) is reported to be involved in tumor progression in some malignant tumors. However, the role of PROK2 in the development of cervical cancer remains unknown. Our results indicate that PROK2 is overexpressed in the human cervical cancer. Cervical cancer patients with high PROK2 expression have a shorter overall survival rate (OS) and disease-free survival rate (DFS). PROK2 acts as a potential biomarker for predicting OS and DFS of cervical cancer patients. We further show that PROK2 is important factor for oncogenic migration and invasion in human cervical cancer cells. Knockdown PROK2 significantly inhibited cell migration, invasion, and MMP15 protein expression in HeLa cells. High expression of MMP15 is confirmed in the human cervical cancer, is significantly associated with the shorter overall survival rate (OS) and is correlated with PROK2 expression. Overexpression of PROK2 using PROK2 plasmid significantly reverses the function of knockdown PROK2, and further upregulates MMP15 expression, migration and invasion of human cervical cancer cells. In conclusion, our findings are the first to demonstrate the role of PROK2 as a novel and potential biomarker for clinical use, and reveal the oncogenic functions of PROK2 as therapeutic target for cervical cancer.

Timosaponin AIII inhibits metastasis of renal carcinoma cells through suppressing cathepsin C expression by AKT/miR-129-5p axis.

Timosaponin AIII (TSAIII) is a steroidal saponin that exerts anticancer activity on various cancer cells. In this study, we explore the effects of TSAIII on renal cell carcinoma (RCC) cells. Our findings show that TSAIII treatment (<8 µM) insignificantly influenced cell viability and cell cycle distribution of human RCC cell lines 786-O, A-498, and ACHN. Further observations revealed that TSAIII inhibited migration and invasion of 786-O and A-498 cells, as well as significantly decreased the production and expression of cathepsin C (CTSC) in both the cell types. Kinase cascade analysis exhibited that PI3K/AKT activation was inhibited, but PTEN expression was increased, in response to TSAIII treatments. Combining TSAIII and PI3K inhibitors, LY294002 synergically reduced the migration and invasion of 786-O and A-498 cells, as well as decreased the CTSC expression in both the cell types. We also observed that miR-129-5p bound to CTSC gene and suppressed the expression of CTSC and demonstrated that the miR-129-5p expression was synergically enhanced by TSAIII and LY294002. In addition, pretreatment with antago-miR-129-5p significantly restored the CTSC expression and the migration and invasion of TSAIII-treated 786-O cells. In conclusion, our findings reveal that TSAIII inhibits the metastatic properties of RCC cells, contributing to the inhibition of PI3K/AKT and the increase of miR-129-5p and the subsequent downregulation of CTSC. This suggests that TSAIII has significant antimetastatic activity against RCC cells and may be beneficial to RCC treatments.

Praeruptorin-B Inhibits 12-O-Tetradecanoylphorbol-13-Acetate-Induced Cell Invasion by Targeting AKT/NF-κB via Matrix Metalloproteinase-2/-9 Expression in Human Cervical Cancer Cells.

BACKGROUND/AIMS: Praeruptorins, a seselin-type coumarin, possess anti-inflammatory and antitumor promoting properties. However, molecular mechanisms through which Praeruptorin-B (Pra-B) exerts an antimetastatic effect on cervical cancer cells remain unclear. METHODS: Cell viability was examined using the MTT assay, whereas cell migration and invasion were examined using the Boyden chamber assay. Western blotting and RT-PCR were performed to investigate the inhibitory effect of Pra-B on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced matrix metalloproteinase-2/-9 (MMP-2/-9) expression in HeLa cells. The findings of the luciferase assay confirmed the inhibitory effect of Pra-B on TPA-induced transcriptional activity of MMP2/-9 in HeLa cells. RESULTS: Pra-B inhibited TPA-induced metastatic ability of human cervical cancer cells without any significant toxicity. Pra-B suppressed TPA-induced mRNA and protein expression and transcriptional activity of MMP-2/-9 in HeLa cells. Furthermore, Pra-B inhibited AKT phosphorylation but did not affect the MAPK pathway. Cotreatment of HeLa cells with TPA plus Pra-B or LY294002 (a PI3K inhibitor) reduced cell invasion and MMP-2/-9 expression and transcriptional activity. In addition, Pra-B attenuated TPA-induced nuclear translocation of NF-κB-p65/-p50, which reduced Ikk-α phosphorylation in HeLa cells. Cotreatment of HeLa cells with TPA plus Pra-B or LY294002 reduced NF-κB nuclear translocation. CONCLUSION: These results suggested that Pra-B-mediated inhibition of TPA-induced cell metastasis involved the suppression of p-AKT/NF-κB via MMP-2/-9 expression in HeLa cells. Pra-B can be a potential antimetastatic agent against cervical cancer.

Functional characterization and architecture of recombinant yeast SWR1 histone exchange complex.

We have prepared recombinant fourteen subunit yeast SWR1 complex from insect cells using a modified MultiBac system. The 1.07 MDa recombinant protein complex has histone-exchange activity. Full exchange activity is realized with a single SWR1 complex bound to a nucleosome. We also prepared mutant complexes that lack a variety of subunits or combinations of subunits and these start to reveal roles for some of these subunits as well as indicating interactions between them in the full complex. Complexes containing a series of N-terminally and C-terminally truncated Swr1 subunits reveal further details about interactions between subunits as well as their binding sites on the Swr1 subunit. Finally, we present electron microscopy studies revealing the dynamic nature of the complex and a 21 Å resolution reconstruction of the intact complex provides details not apparent in previously reported structures, including a large central cavity of sufficient size to accommodate a nucleosome.

The structure and function of an RNA polymerase interaction domain in the PcrA/UvrD helicase.

The PcrA/UvrD helicase functions in multiple pathways that promote bacterial genome stability including the suppression of conflicts between replication and transcription and facilitating the repair of transcribed DNA. The reported ability of PcrA/UvrD to bind and backtrack RNA polymerase (1,2) might be relevant to these functions, but the structural basis for this activity is poorly understood. In this work, we define a minimal RNA polymerase interaction domain in PcrA, and report its crystal structure at 1.5 Å resolution. The domain adopts a Tudor-like fold that is similar to other RNA polymerase interaction domains, including that of the prototype transcription-repair coupling factor Mfd. Removal or mutation of the interaction domain reduces the ability of PcrA/UvrD to interact with and to remodel RNA polymerase complexes in vitro. The implications of this work for our understanding of the role of PcrA/UvrD at the interface of DNA replication, transcription and repair are discussed.

Norcantharidin induces mitochondrial-dependent apoptosis through Mcl-1 inhibition in human prostate cancer cells.

Norcantharidin (NCTD) is the demethylated form of cantharidin that exhibits anticancer potential in many cancer cell types. Recent reports suggest that NCTD targeting ROS/AMPK and DNA replication signaling pathway could be an effective strategy for the treatment of PCa cells. However, supportive evidence is limited to the effect of NCTD that induction of apoptosis through suppression of the Mcl-1. Here, we show that NCTD induced PCa cell apoptosis and triggered caspase activation, which was associated with mitochondria dysfunction. Mechanistic investigations suggested that NCTD modulated the Akt signaling via increased nuclear translocation and interaction with the myeloid cell leukemia-1 (Mcl-1) promoter by FOXO4, resulting in an apoptotic effect. Moreover, miR-320d, which targets Mcl-1, was significantly upregulated after NCTD treatment. Overexpression of miR-320d by NCTD induced mitochondria dysfunction and apoptosis, which was notably attenuated with a miR-320d inhibitor. In vivo xenograft analysis revealed that NCTD significantly reduced tumor growth in mice with PC3 tumor xenografts. Taken together, our results provide new insights into the critical role of NCTD in suppressing Mcl-1 via epigenetic upregulation of miR-320d, resulting in PCa cell apoptosis.

Protodioscin Induces Apoptosis Through ROS-Mediated Endoplasmic Reticulum Stress via the JNK/p38 Activation Pathways in Human Cervical Cancer Cells.

BACKGROUND/AIMS: Protodioscin (PD) is a steroidal saponin with anti-cancer effects on a number of cancer cells, but the anti-tumor effects and mechanism of action of PD on human cervical cancer cells is unclear. METHODS: We determined cell viability using the MTT assay. Cell death, mitochondrial membrane potential (MMP), intracellular reactive oxygen species (ROS) generation, and endoplasmic reticulum (ER) stress were measured on a flow cytometry. Caspase activation, ER stress, and MMP-dependent apoptosis proteins in cervical cancer cells in response to PD were determined by Western blot analysis. The ability of ATF4 binding to ChIP promoter was measured using the ChIP assay. RESULTS: We demonstrated that PD inhibits cell viability, causes a loss of mitochondrial function, and induces apoptosis, as evidenced by up-regulation of caspase-8, -3, -9, -PARP, and Bax activation, and down-regulation of Bcl-2 expression. PD was shown to induce ROS and the ER stress pathway, including GRP78, p-eIF-2α, ATF4, and CHOP. Pre-treatment with NAC, a ROS production inhibitor, significantly reduced ER stress and apoptosis-related proteins induced by PD. Transfection of GRP78/CHOP-siRNA effectively inhibited PD-induced ER stress-dependent apoptosis. Moreover, treatment with PD significantly increased p38 and JNK activation. Co-administration of a JNK inhibitor (SP600125) or p38 inhibitor (SB203580) abolished cell death and ER stress effects during PD treatment. In addition, PD induced the expression of nuclear ATF4 and CHOP, as well as the binding ability of ATF4 to the CHOP promoter. CONCLUSION: Our results suggest that PD is a promising therapeutic agent for the treatment of human cervical cancer.

Nimbolide induced apoptosis by activating ERK-mediated inhibition of c-IAP1 expression in human hepatocellular carcinoma cells.

Nimbolide is one of the major compounds from the leaves and flowers of the neem tree and exhibits antitumor properties on various cancer cells. However, no report has shown that nimbolide induces apoptosis in vitro and in vivo in human hepatocellular carcinoma cells. Our results indicated that it inhibited cell growth in Huh-7 and PLC/PRF/5 cells. We also found that nimbolide induced cell death through the induction of G2/M phase arrest and mitochondrial dysfunction, accompanied by the increased expression of cleaved caspase-7, caspase-9, caspase-3, caspase-PARP, and Bax and decreased expression of Mcl-1 and Bcl-2. A human apoptosis antibody array analysis demonstrated that inhibition of the apoptosis family proteins (XIAP, c-IAP1, and c-IAP2) was one of the major targets of nimbolide. Additionally, nimbolide sustained activation of ERK expression. Moreover, pretreatment with U0126 (MEK inhibitor) markedly abolished nimbolide-inhibited cell viability, induced cell apoptosis, ERK phosphorylation, cleaved caspase-9, caspase-3, cleaved-PARP activation, and increased c-IAP1 expression in Huh-7 cells. An in vivo study showed that nimbolide significantly reduced Huh-7 tumor growth and weight in a xenograft mouse model. This study indicated the antitumor potential of nimbolide in human hepatocellular carcinoma cells.

Synergistic antimetastatic effect of cotreatment with licochalcone A and sorafenib on human hepatocellular carcinoma cells through the inactivation of MKK4/JNK and uPA expression.

To improve the clinical outcome of tumor chemotherapy, more effective combination treatments against tumor metastasis and recurrence are required. Licochalcone A (LicA) is the root of Glycyrrhiza inflata and has been reported to possess anti-inflammatory, antimicrobial, and antitumor effects. Sorafenib (Sor), a multikinase inhibitor, is used to treat patients with solid tumors such as advanced hepatocellular carcinoma (HCC). However, the synergistic effects of LicA and Sor on the metastasis of human HCC cells have not been reported. We found that LicA and Sor did not have cytotoxic effects or arrest growth in human SK-Hep-1 and Huh-7 cells. In addition, treatment with LicA or Sor alone inhibited migration and invasion in human SK-Hep-1 and Huh-7 HCC cells. Furthermore, cotreatment with LicA and Sor synergistically inhibited the migration and invasion of HCC cells and significantly inhibited uPA protein expression. Notably, cotreatment of LicA and Sor synergistically and significantly downregulated MKK4-JNK expression. Through tail vein injection in nude mice, the aforementioned cotreatment synergistically suppressed SK-Hep-1 cell-mediated lung metastasis. These findings first revealed the synergistic effects of LicA and Sor cotreatment against human HCC cells, further suggesting that beneficial effects on tumor regression could be confirmed through prospective clinical trials.

Alpha-Mangostin Suppresses the Metastasis of Human Renal Carcinoma Cells by Targeting MEK/ERK Expression and MMP-9 Transcription Activity.

BACKGROUND/AIMS: α-mangostin has anti-carcinogenic effects against several cancers. We investigated the molecular mechanism of this compound on the metastasis of human renal carcinoma cells. METHODS: Cell viability was measured using the MTT assay, and cell cycle distribution using flow cytometry. A Matrigel-based assay was used to measure in vitro cell migration and invasion. MAPK-related proteins and matrix metalloproteinase (MMP)-9 and MMP-2 expression were measured by western blotting, and MMP2/-9 activities were determined by gelatin zymography. RT-qPCR and a luciferase assay were used to examine the transcriptional activity of MMP-9. RESULTS: α-mangostin inhibited the migration and invasion of RCC cells in a dose-dependent manner, but had no evident cytotoxic effects. Treatment of 786-O cells with α-mangostin inhibited activation of MEK and ERK. Treatment with a specific MEK inhibitor (U0126) enhanced the inhibitory effects of α-mangostin on cell migration and invasion, and the phosphorylation of ERK and MEK. Moreover, α-mangostin inhibited the expression of the MMP-9 mRNA levels as well as the activity of MMP-9 promoter, and these suppressive effects were further enhanced by U0126. CONCLUSIONS: Our results suggest that α-mangostin suppresses cell migration and invasion via MEK/ERK/MMP9 pathway, and might be a promising anti-metastatic agent against human renal cell carcinoma.

ß-mangostin suppresses human hepatocellular carcinoma cell invasion through inhibition of MMP-2 and MMP-9 expression and activating the ERK and JNK pathways.

ß-mangostin is a dietary xanthone that has been reported to have the anticancer properties in some human cancer cell types. However, the antimetastatic effect and molecular mechanism of ß-mangostin action in human hepatocellular carcinoma (HCC) cells remain unknown. In this study, we found that ß-mangostin did not induce cytotoxicity in human HCC cells (SK-Hep-1, Huh-7 and HA22T/VGH cells). ß-mangostin could inhibit migration and invasion of human HCC cells. Meanwhile, ß-mangostin significantly decreased the protein activities and expression of matrix metalloproteinase (MMP)-2 and MMP-9 via increasing the activation of MEK1/2, ERK1/2, MEK4 and JNK1/2 signaling pathways. Furthermore, using specific inhibitor for ERK1/2 (PD98059) and JNK1/2 (JNKII) significantly restored the expression of MMP-2/-9 and invasion by ß-mangostin treatment in Huh-7 cells. In addition, ß-mangostin effectively restored the protein levels and transcription activity of MMP-2 and MMP-9 in siERK or siJNK-transfected Huh-7 cells, concomitantly with promotion on cell migration and invasion. Taken together, these findings are the first to demonstrate the antimetastatic activity of ß-mangostin against human HCC cells, which may act as a promising therapeutic agent for the treatment of HCC.