Su Hyun Hong

Anti-invasive activity of sanguinarine through modulation of tight junctions and matrix metalloproteinase activities in MDA-MB-231 human breast carcinoma cells.

Tight junctions (TJs) are critical structures for the maintenance of cellular polarity, acting as paracellular permeability barriers and playing an essential role in regulation of the diffusion of fluid, electrolytes and macromolecules through the paracellular pathway. Matrix metalloproteinases (MMPs) have been implicated as possible mediators of invasiveness and metastasis in some cancers. In this study, it was investigated the effect of sanguinarine, a benzophenanthridine alkaloid, on the correlation between the tightening of TJs and the anti-invasive activity in human breast carcinoma MDA-MB-231 cells. The inhibitory effects of sanguinarine on cell proliferation, motility and invasiveness were found to be associated with the increased tightness of the TJ, which was demonstrated by an increase in transepithelial electrical resistance (TER). Additionally, immunoblotting results indicated that sanguinarine repressed the levels of the claudin proteins, major components of TJs that play a key role in the control and selectivity of paracellular transport. Furthermore, the activities of MMP-2 and -9 in MDA-MB-231 cells were dose-dependently inhibited by treatment with sanguinarine, and this was also correlated with a decrease in the expression of their mRNA and proteins.

The flavonoid morin from Moraceae induces apoptosis by modulation of Bcl-2 family members and Fas receptor in HCT 116 cells

It is evident based on literature that flavonoids from fruit can safely modulate cancer cell biology and induce apoptosis. Therefore, we investigated the anticancer activity of morin, a flavonoid which is plentiful in twigs of mulberry focusing on apoptosis, and its mechanisms. Morin upregulated the Fas receptor, and activates caspase-8, -9 and -3 in HCT-116 cells. Morin also activates Bid, and induced the loss of mitochondrial membrane potential (MMP, ∆Ψm) with Bax protein activation and cytochrome c release. In addition, morin induced ROS generation which was not blocked by N-acetylcysteine. Morin also suppressed Bcl-2 and cIAP-1, anti-apoptotic proteins, which may contribute to augmentation of morin-triggered apoptosis. As an upstream signaling pathway, suppressed Akt activity by morin was associated to apoptosis. This study suggests that morin induces caspase-dependent apoptosis through extrinsic pathway by upregulating Fas receptor as well as through the intrinsic pathway by modulating Bcl-2 and IAP family members, and ROS generation, and that Akt is the critical upstream signaling that regulates the apoptotic effect of morin in human colon cancer HCT-116 cells.

Morin, a Flavonoid from Moraceae, Induces Apoptosis by Induction of BAD Protein in Human Leukemic Cells

Evidence suggests that phytochemicals can safely modulate cancer cell biology and induce apoptosis. Here, we investigated the anti-cancer activity of morin, a flavone originally isolated from members of the Moraceae family in human leukemic cells, focusing on apoptosis. An anti-cancer effect of morin was screened with several human leukemic cell lines. U937 cells were most sensitive to morin, where it induced caspase-dependent apoptosis in a dose-dependent manner. It also induced loss of MMP (ΔΨm) along with cytochrome c release, down-regulated Bcl-2 protein, and up-regulated BAX proteins. The apoptotic activity of morin was significantly attenuated by Bcl-2 augmentation. In conclusion, morin induced caspase-dependent apoptosis through an intrinsic pathway by upregulating BAD proteins. In addition, Bcl-2 protein expression is also important in morin-induced apoptosis of U937 cells. This study provides evidence that morin might have anticancer properties in human leukemic cells.

Bufalin prevents the migration and invasion of T24 bladder carcinoma cells through the inactivation of matrix metalloproteinases and modulation of tight junctions.

Bufalin, a cardiotonic steroid extracted from toad venom, has generally been known to possess a range of biological activities; however, only a few studies have reported the anti-metastatic activity of bufalin. In the present study, we investigated the inhibitory effects of bufalin on cell migration and invasion, two critical cellular processes that are often deregulated during metastasis, using the human bladder cancer cell line, T24. Within the concentration range that was not cytotoxic, bufalin markedly inhibited the cell motility and invasiveness of T24 cells. The inhibitory effects of bufalin on cell invasiveness were associated with the tightening of tight junctions (TJs), which was demonstrated by an increase in transepithelial electrical resistance (TER). Bufalin treatment also repressed the levels of claudin proteins (claudin-2, -3 and -4) and the major components of TJs that play key roles in the control and selectivity of paracellular transport. Furthermore, the activities of matrix metalloproteinase (MMP)‑2 and -9 in T24 cells were dose‑dependently inhibited by treatment with bufalin and this also correlated with a decrease in their mRNA and protein expression levels; however, the mRNA and protein levels of the tissue inhibitor of metalloproteinase (TIMP)‑1 and -2 were increased. In addition, these effects were related to the increased phosphorylation of the extracellular signal-regulated protein kinase (ERK) pathway. The inhibition of ERK (PD98059) significantly prevented the bufalin‑induced suppression of T24 cell migration. These findings suggest that bufalin inhibits the migration and invasion of T24 cells by modulating the activity of TJs and MMPs, possibly in association with the activation of ERK.

Spermidine Protects against Oxidative Stress in Inflammation Models Using Macrophages and Zebrafish

Spermidine is a naturally occurring polyamine compound that has recently emerged with anti-aging properties and suppresses inflammation and oxidation. However, its mechanisms of action on anti-inflammatory and antioxidant effects have not been fully elucidated. In this study, the potential of spermidine for reducing pro-inflammatory and oxidative effects in lipopolysaccharide (LPS)-stimulated macrophages and zebrafish was explored. Our data indicate that spermidine significantly inhibited the production of pro-inflammatory mediators such as nitric oxide (NO) and prostaglandin E2 (PGE2), and cytokines including tumor necrosis factor-α and interleukin-1β in RAW 264.7 macrophages without any significant cytotoxicity. The protective effects of spermidine accompanied by a marked suppression in their regulatory gene expression at the transcription levels. Spermidine also attenuated the nuclear translocation of NF-κB p65 subunit and reduced LPS-induced intracellular accumulation of reactive oxygen species (ROS) in RAW 264.7 macrophages. Moreover, spermidine prevented the LPS-induced NO production and ROS accumulation in zebrafish larvae and was found to be associated with a diminished recruitment of neutrophils and macrophages. Although more work is needed to fully understand the critical role of spermidine on the inhibition of inflammation-associated migration of immune cells, our findings clearly demonstrate that spermidine may be a potential therapeutic intervention for the treatment of inflammatory and oxidative disorders.

Mori folium inhibits interleukin-1β-induced expression of matrix metalloproteinases and inflammatory mediators by suppressing the activation of NF-κB and p38 MAPK in SW1353 human chondrocytes

The pro-inflammatory cytokine interleukin-1β (IL-1β) is known to play a crucial role in the pathogenesis of osteoarthritis (OA) by stimulating several mediators that contribute to cartilage degradation. Mori folium, the leaves of Morus alba L., has long been used in traditional medicine to treat diabetes, protect the liver, and lower blood pressure; however, the role of Mori folium in OA is not yet fully understood. Therefore, in the present study, we investigated whether Mori folium water extract (MF) inhibited the catabolic effects of IL-1β in vitro, and also whether it inhibited the matrix metalloproteinases (MMPs), inducible nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2) through the attenuation of nuclear factor-κB (NF-κB) and mitogen activated protein kinase (MAPK) pathways in SW1353 human chondrocytes. MMP proteins in culture medium were determined using a cytokine‑specific enzyme-linked immunosorbent assay (ELISA). The production of NO and prostaglandin E2 (PGE2) were evaluated using Griess reagent and ELISA. Subsequently, the mRNA and protein levels of MMPs, iNOS, COX-2, NF-κB and MAPKs were examined by RT-qPCR and/or western blot analysis. The results indicate that MF significantly reduced the IL-1β‑induced release of MMP-1 and -13 in SW1353 cells, which was associated with the inhibition of MMP-1 and -13 mRNA and protein expression in a concentration‑dependent manner at concentrations with no cytotoxicity. MF also attenuated the IL-1β-induced production of NO and PGE2, and reduced iNOS and COX-2 expression. Furthermore, we noted that MF markedly suppressed the IL-1β‑induced nuclear translocation of NF-κB, which correlated with the inhibitory effects of MF on inhibitor-κB (IκB) degradation, and the phosphorylation of p38 MAPK was selectively restored by MF upon IL-1β stimulation. These results indicate that MF inhibited the production and expression of MMP-1 and -13 and inflammatory mediators, at least in part, through suppressing the activation of either NF-κB or p38 MAPK in IL-1β-treated SW1353 chondrocytes. Therefore, the novel findings of the present study suggest that MF is a potential therapeutic choice for chondroprotection against the collagen matrix breakdown in the cartilage of diseased tissues, such as those found in patients with arthritic disorders.

Oleifolioside B-mediated autophagy promotes apoptosis in A549 human non-small cell lung cancer cells

The biochemical mechanisms of cell death by oleifolioside B (OB), a cycloartane-type triterpene glycoside isolated from Dendropanax morbifera Leveille, were investigated in A549 human lung carcinoma cells. Our data indicated that exposure to OB led to caspase activation and typical features of apoptosis; however, apoptotic cell death was not prevented by z-VAD-fmk, a pan-caspase inhibitor, demonstrating that OB-induced apoptosis was independent of caspase activation. Subsequently, we found that OB increased autophagy, as indicated by an increase in monodansylcadaverine fluorescent dye-labeled autophagosome formation and in the levels of the autophagic form of microtubule-associated protein 1 light chain 3 and Atg3, an autophagy-specific gene, which is associated with inhibiting phospho-nuclear factor erythroid 2-related factor 2 (Nrf2) expression. However, pretreatment with bafilomycin A1, an autophagy inhibitor, attenuated OB-induced apoptosis and dephosphorylation of Nrf2. The data suggest that OB-induced autophagy functions as a death mechanism in A549 cells and OB has potential as a novel anticancer agent capable of targeting apoptotic and autophagic cell death and the Nrf2 signaling pathway.

Baicalein induces apoptosis via ROS-dependent activation of caspases in human bladder cancer 5637 cells

Baicalein is a flavonoid derived originally from the root of Scutellaria baicalensis Georgi, which has been used in Oriental medicines for treating various diseases. Although this compound has been reported to have anticancer activities in several human cancer cell lines, the therapeutic effects of baicalein on human bladder cancer and its mechanisms of action have not been extensively studied. This study investigated the proapoptotic effects of baicalein in human bladder cancer 5637 cells. For this study, cell viability and apoptosis were evaluated using the 3-(4,5-dimethylthia-zol-2-yl)-2,5-diphenyltetrazolium bromide assay, trypan blue dye exclusion assay 4,6-diamidino-2-phenylindole staining, and flow cytometry. Measurements of the mitochondrial membrane potential (MMP), caspase activity assays and western blots were conducted to determine whether 5637 cell death occurred by apoptosis. Treatment with baicalein resulted in a concentration-dependent growth inhibition coupled with apoptosis induction, as indicated by the results of nuclei morphology examination and flow cytometry analyses. The induction of the apoptotic cell death of 5637 cells by baicalein exhibited a correlation with the downregulation of members of the inhibitor of apoptosis protein (IAP) family, including cIAP-1 and cIAP-2, and the activation of caspase-9 and -3 accompanied by proteolytic degradation of poly(ADP-ribose)-polymerase. The study also showed that baicalein decreases the expression of the proapoptotic protein Bax, increases antiapoptotic Bcl-2 expression, and noticeably aggravates the loss of MMP. Concomitantly, the data showed that baicalein increases the levels of death receptors and their associated ligands and enhances the activation of caspase-8 and truncation of Bid. However, the pan-caspase inhibitor can reverse baicalein-induced apoptosis, demonstrating that it is a caspase-dependent pathway. Moreover, it was found that baicalein can induce the production of reactive oxygen species (ROS) and that pretreatment with the antioxidant N-acetyl-L-cysteine significantly attenuates the baicalein effects on the loss of MMP and activation of caspase. In addition, the blocking of ROS generation decreases the apoptotic activity and antiproliferative effect of baicalein, indicating that baicalein induces apoptosis of 5637 cells through the ROS-dependent activation of caspases.

Baicalein protects C6 glial cells against hydrogen peroxide-induced oxidative stress and apoptosis through regulation of the Nrf2 signaling pathway

Baicalein, a flavonoid originally obtained from the roots of Scutellaria baicalensis Georgi, has been reported to possess various biological properties. Although several studies have demonstrated the anti-oxidative activity of baicalein, its neuroprotective mechanisms have not been clearly established. The present study aimed to detect the effects of baicalein against hydrogen peroxide (H2O2)-induced neuronal damage in C6 glial cells and to investigate the molecular mechanisms involved in this process. The results demonstrated that baicalein effectively inhibited H2O2-induced growth and reactive oxygen species (ROS) generation. We noted that Baicalein also attenuated the H2O2‑induced formation of comet tail, phosphorylation of p-γH2A.X, loss of mitochondrial membrane potential (MMP or ΔΨm), and changes to apoptosis‑related protein expression, which suggests that it can prevent H2O2‑induced cellular DNA damage and apoptotic cell death. Furthermore, treatment with baicalein effectively induced the expression of nuclear factor-erythroid 2-related factor 2 (Nrf2) as well as heme oxygenase-1 (HO-1) and thioredoxin reductase 1 (TrxR1) in a concentration and time-dependent manner. Moreover, the protective effects of baicalein against H2O2‑induced DNA damage and apoptosis were abolished by zinc protoporphyrin (ZnPP) IX, a HO-1 inhibitor, and auranofin, a TrxR inhibitor. In addition, we noted that the cytoprotective effects of baicalein were attenuated by transient transfection with Nrf2-specific small interfering RNA (siRNA). The findings of our present study suggest that baicalein enhances cellular antioxidant defense capacity through the inhibition of ROS generation and the activation of the Nrf2 signaling pathway, thus protecting C6 cells from H2O2-induced neuronal damage.

Induction of apoptosis in MDA-MB-231 human breast carcinoma cells with an ethanol extract of Cyperus rotundus L. by activating caspases

Cyperus rotundus L. belongs to the Cyperaceae family and is a well documented traditional medicinal herb. Its rhizome has been reported to possess wide spectrum pharmacological activities including anti-inflammatory and antioxidant activity. However, the cellular and molecular mechanisms of the anticancer activity have not been elucidated. In the present study, we investigated the pro-apoptotic effects of C. rotundu rhizomes in a human breast carcinoma MDA-MB-231 cell model. Treatment of MDA-MB-231 cells with an ethanol extract of C. rotundu rhizomes (EECR) and a methanol extract of C. rotundu rhizomes (MECR), but not a water extract of C. rotundu rhizomes, resulted in potent antiproliferative activity. The activity of the EECR was higher than that of the MECR and was associated with the induction of apoptosis. The induction of apoptosis by the EECR was associated with upregulation of death receptor 4 (DR4), DR5 and pro-apoptotic Bax, as well as downregulation of anti-apoptotic survivin and Bcl-2. EECR treatment also downregulated Bid expression and activated caspase-8 and -9, the respective initiator caspases of the extrinsic and intrinsic apoptotic pathways. The increase in mitochondrial membrane depolarization was correlated with activation of effector caspase-3 and cleavage of poly(ADP-ribose) polymerase, a vital substrate of activated caspase-3. Blockage of caspase activation by pretreatment with a pan-caspase inhibitor consistently inhibited apoptosis and abrogated growth inhibition in EECR-treated MDA-MB-231 cells. Although reactive oxygen species (ROS) increased following treatment with the EECR, inhibiting ROS with a ROS scavenger did not attenuate EECR-induced apoptosis. Furthermore, inhibitors of phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinase (MAPK) signaling pathways failed to reverse EECR-induced apoptosis and growth inhibition. These results suggest that the pro-apoptotic activity of the EECR may be regulated by a caspase-dependent cascade through activation of both intrinsic and extrinsic signaling pathways that is not associated with ROS generation or the PI3K/Akt and MAPK pathways.