• Journal of Life Science
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• v.23 no.4
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• pp.518-528
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• 2013

Scutellaria baicalensis, belonging to the family Labiatae, is widely distributed in Korea, China, Mongolia, and eastern Siberia. It has been used in traditional medicine for various diseases, such as dysentery, pyrexia, jaundice, and carbuncles. In addition, S. baicalensis is reported to possess various beneficial pharmacological activities, including anti-inflammatory, antidiabetic, antiviral, antihypertension, antioxidant, and anticancer effects. However, the molecular mechanisms of its anticancer activity have not been clearly elucidated. In the present study, we investigated the proapoptotic effects of ethanol extract of S. baicalensis (EESB) on human renal cell carcinoma Caki-1 cells. The anti-proliferative activity of EESB was associated with apoptosis induction, which was associated with the up-regulation of death receptor 4, the Fas ligand, and Bax and the down-regulation of Bid, XIAP, and cIAP-1 proteins. EESB treatment also induced mitochondrial dysfunction, proteolytic activation of caspase-3, -8, and -9 and degradation of caspase-3 substrate proteins, such as poly (ADP-ribose) polymerase, ${\beta}$-catenin, and phospholipase C-${\gamma}1$. However, pretreatment of a pan-caspase inhibitor, z-VAD-fmk, significantly attenuated the EESB-induced apoptosis. Taken together, these findings suggest that EESB may be a potential chemotherapeutic agent. Further studies will be needed to identify the active compounds that confer the anticancer activity of S. baicalensis.

• Journal of Ginseng Research
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• v.45 no.1
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• pp.126-133
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• 2021

Background: 20(S)-protopanaxadiol (20(S)-PPD), one of the aglycone derivatives of major ginsenosides, has been shown to have an anticancer activity toward a variety of cancers. This study was initiated with an attempt to evaluate its anti-cancer activity toward human endometrial cancer by cell and xenograft mouse models. Methods: Human endometrial cancer (HEC)-1A cells were incubated with different 20(S)-PPD concentrations. 20(S)-PPD cytotoxicity was evaluated using MTT assay. Apoptosis was detected using the annexin V binding assay and cell cycle analysis. Cleaved poly (ADP-ribose) polymerase (PARP) and activated caspase-9 were assessed using western blotting. HEC-1A cell tumor xenografts in athymic mice were generated by inoculating HEC-1A cells into the flank of BALB/c female mice and explored to validate 20(S)-PPD anti-endometrial cancer toxicity. Results: 20(S)-PPD inhibited HEC-1A cell proliferation in a dose-dependent manner with an IC50 value of 3.5 μM at 24 h. HEC-1A cells morphologically changed after 20(S)-PPD treatment, bearing resemblance to Taxol-treated cells. Annexin V-positive cell percentages were 0%, 10.8%, and 58.1% in HEC-1A cells when treated with 0, 2.5, and 5 μM of 20(S)-PPD, respectively, for 24 h. 20(S)-PPD subcutaneously injected into the HEC-1A cell xenograft-bearing mice three times a week for 17 days manifested tumor growth inhibition by as much as 18% at a dose of 80 mg/kg, which sharply contrasted to controls that showed an approximately 2.4-fold tumor volume increase. These events paralleled caspase-9 activation and PARP cleavage. Conclusion: 20(S)-PPD inhibits endometrial cancer cell proliferation by inducing cell death via a caspase-mediated apoptosis pathway. Therefore, the 20(S)-PPD-like ginsenosides are endowed with ample structural information that could be utilized to develop other ginsenoside-based anticancer agents.

• Biomolecules & Therapeutics
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• v.31 no.1
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• pp.73-81
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• 2023

Sirtuins (SIRTs) belong to the nicotinamide adenine dinucleotide (NAD+)-dependent class III histone deacetylase family. They are key regulators of cellular and physiological processes, such as cell survival, senescence, differentiation, DNA damage and stress response, cellular metabolism, and aging. SIRTs also influence carcinogenesis, making them potential targets for anticancer therapeutic strategies. In this study, we investigated the anticancer properties and underlying molecular mechanisms of a novel SIRT1 inhibitor, MHY2251, in human colorectal cancer (CRC) cells. MHY2251 reduced the viability of various human CRC cell lines, especially those with wild-type TP53. MHY2251 inhibited SIRT1 activity and SIRT1/2 protein expression, while promoting p53 acetylation, which is a target of SIRT1 in HCT116 cells. MHY2251 treatment triggered apoptosis in HCT116 cells. It increased the percentage of late apoptotic cells and the sub-G1 fraction (as detected by flow cytometric analysis) and induced DNA fragmentation. In addition, MHY2251 upregulated the expression of FasL and Fas, altered the ratio of Bax/Bcl-2, downregulated the levels of pro-caspase-8, -9, and -3 proteins, and induced subsequent poly(ADP-ribose) polymerase cleavage. The induction of apoptosis by MHY2251 was related to the activation of the caspase cascade, which was significantly attenuated by pre-treatment with Z-VAD-FMK, a pan-caspase inhibitor. Furthermore, MHY2251 stimulated the phosphorylation of c-Jun N-terminal kinase (JNK), and MHY2251-triggered apoptosis was blocked by pre-treatment with SP600125, a JNK inhibitor. This finding indicated the specific involvement of JNK in MHY2251-induced apoptosis. MHY2251 shows considerable potential as a therapeutic agent for targeting human CRC via the inhibition of SIRT1 and activation of JNK/p53 pathway.

• Biomolecules & Therapeutics
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• v.28 no.6
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• pp.561-568
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• 2020

We examined the anticancer effects of a novel sirtuin inhibitor, MHY2256, on HCT116 human colorectal cancer cells to investigate its underlying molecular mechanisms. MHY2256 significantly suppressed the activity of sirtuin 1 and expression levels of sirtuin 1/2 and stimulated acetylation of forkhead box O1, which is a target protein of sirtuin 1. Treatment with MHY2256 inhibited the growth of the HCT116 (TP53 wild-type), HT-29 (TP53 mutant), and DLD-1 (TP53 mutant) human colorectal cancer cell lines. In addition, MHY2256 induced G0/G1 phase arrest of the cell cycle progression, which was accompanied by the reduction of cyclin D1 and cyclin E and the decrease of cyclin-dependent kinase 2, cyclin-dependent kinase 4, cyclin-dependent kinase 6, phosphorylated retinoblastoma protein, and E2F transcription factor 1. Apoptosis induction was shown by DNA fragmentation and increase in late apoptosis, which were detected using flow cytometric analysis. MHY2256 downregulated expression levels of procaspase-8, -9, and -3 and led to subsequent poly(ADP-ribose) polymerase cleavage. MHY2256-induced apoptosis was involved in the activation of caspase-8, -9, and -3 and was prevented by pretreatment with Z-VAD-FMK, a pan-caspase inhibitor. Furthermore, the autophagic effects of MHY2256 were observed as cytoplasmic vacuolation, green fluorescent protein-light-chain 3 punctate dots, accumulation of acidic vesicular organelles, and upregulated expression level of light-chain 3-II. Taken together, these results suggest that MHY2256 could be a potential novel sirtuin inhibitor for the chemoprevention or treatment of colorectal cancer or both.

• Molecules and Cells
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• v.24 no.1
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• pp.95-104
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• 2007

The mechanism of acacetin-induced apoptosis of human breast cancer MCF-7 cells was investigated. Acacetin caused 50% growth inhibition ($IC_{50}$) of MCF-7 cells at $26.4{\pm}0.7{\mu}M$ over 24 h in the MTT assay. Apoptosis was characterized by DNA fragmentation and an increase of sub-G1 cells and involved activation of caspase-7 and PARP (poly-ADP-ribose polymerase). Maximum caspase 7 activity was observed with $100{\mu}M$ acacetin for 24 h. Caspase 8 and 9 activation cascades mediated the activation of caspase 7. Acacetin caused a reduction of Bcl-2 expression leading to an increase of the Bax:Bcl-2 ratio. It also caused a loss of mitochondrial membrane potential that induced release of cytochrome c and apoptosis inducing factor (AIF) into the cytoplasm, enhancing ROS generation and subsequently resulting in apoptosis. Pretreatment of cells with N-acetylcysteine (NAC) reduced ROS generation and cell growth inhibition, and pretreatment with NAC or a caspase 8 inhibitor (Z-IETD-FMK) inhibited the acacetin-induced loss of mitochondrial membrane potential and release of cytochrome c and AIF. Stress-activated protein kinase/c-Jun $NH_4$-terminal kinase 1/2 (SAPK/JNK1/2) and c-Jun were activated by acacetin but extracellular-regulated kinase 1/2 (Erk1/2) nor p38 mitogen-activated protein kinase (MAPK) were not. Our results show that acacetin-induced apoptosis of MCF-7 cells is mediated by caspase activation cascades, ROS generation, mitochondria-mediated cell death signaling and the SAPK/JNK1/2-c-Jun signaling pathway, activated by acacetin-induced ROS generation.

• Journal of Life Science
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• v.18 no.3
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• pp.336-343
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• 2008

Histone deacetylases (HDACs) inhibitors have emerged as the accessory therapeutic agents for various human cancers, since they can block the activity of specific HDACs, restore the expression of some tumor suppressor genes and induce cell differentiation, cell cycle arrest and apoptosis in vitro and in vivo. In the present study, we investigated that the effect of trichostatin A (TSA), an HDAC inhibitor, on the cell growth and apoptosis, and its effect on the nuclear factor-kappaB $(NF-{\kappa}B)$ activity in 267B1 human prostate epithelial cells. Exposure of 267B1 cells to TSA resulted in growth inhibition and apoptosis induction in and dose-dependent manners as measured by fluorescence microscopy, agarose gel electrophoresis and flow cytometry analysis. TSA treatment inhibited the levels of IAP family members such as c-IAP-1 and c-IAP-2 and induced the proteolytic activation of caspase-3, -8 and -9, which were associated with concomitant degradation of poly (ADP-ribose)-polymerase, ${\beta}-catenin$ and laminin B proteins. The increase in apoptosis by TSA was connected with the translocation of $NF-{\kappa}B$ from cytosol to nucleus, increase of the DNA binding as well as promoter activity of $NF-{\kappa}B$, and degradation of cytosolic inhibitor of KappaB $(I{\kappa}B)-{\alpha}$ protein. We therefore concluded that TSA demonstrated anti-proliferative and apoptosis-inducing effects on 267B1 cells in vitro, and that the activation of caspases and $NF-{\kappa}B$ may play important roles in its mechanism of action. Although further studies are needed, these findings provided important insights into the possible molecular mechanisms of the anti-cancer activity of TSA.

• Journal of Life Science
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• v.29 no.9
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• pp.977-985
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• 2019

Aster yomena (Kitam.) Honda is an edible vegetable and perennial herb belonging to the Asteraceae family, and has been used for a long time for the prevention and treatment of various diseases. Although leaf extracts of A. yomena are known to have antioxidant and anti-inflammatory effects, accurate efficacy assessments are still inadequate. In this study, we investigated whether the antioxidant efficacy of ethanol extract of A. yomena leaf (EEAY) is correlated with the anti-inflammatory effect in RAW 264.7 macrophages. The results showed that EEAY significantly inhibited the hydrogen peroxide ($H_2O_2$)-induced growth inhibition in RAW 264.7 cells, which was associated with increased expression of nuclear factor erythroid 2-related factor-2 (Nrf2) and heme oxygenase-1 (HO-1). EEAY pretreatment also effectively prevented $H_2O_2$-induced reactive oxygen species generation and apoptosis through inhibition of caspase-3 activation and poly (ADP-ribose) polymerase degradation. Additionally, EEAY significantly increased the expression and production of interleukin-10, a representative anti-inflammatory cytokine, which was associated with increased expression of toll-like receptor 4 and myeloid differentiation factor 88 at transcriptional and translational levels. Furthermore, the increased production of nitric oxide (NO) by lipopolysaccharide was markedly abolished under the condition of EEAY pretreatment, and the inhibitory effect of NO production by EEAY was further increased by hemin, an HO-1 inducer. Overall, our results suggest that EEAY is able to activate the Nrf2/HO-1 signaling pathway to protect RAW 264.7 macrophages from oxidative and inflammatory stress.

• Journal of Life Science
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• v.23 no.8
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• pp.1057-1063
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• 2013

Citri Pericarpium is one of the most commonly used traditional herbal medicines in Korea, China, and Japan. Its extracts have many properties including the treatment of indigestion and inflammatory respiratory syndromes such as bronchitis and asthma. However, the underlying molecular mechanisms of anti-cancer activity and molecular targets are not fully understood. In this work, we investigated the anti-proliferative activity of Citri Pericapium (EMCP) methanol extract on reactive oxygen species (ROS) production and the association of these effects with apoptotic cell death using U937 human leukemia cells in vitro. EMCP treatment decreased cell proliferation in a dose-dependent manner following an increase of the sub-G1 phase, the down-regulation of Bax proteins, the activation of caspases, the degradation of poly (ADP-ribose) polymerase proteins (PARP), and the induction of ROS generation. However, the quenching of ROS generation by N-acetyl-L-cysteine administration, a scavenger of ROS, reversed the EMCP-induced apoptosis effects. In addition, heme oxygenase-1 expression also recovered by inhibiting the nuclear translocation of phosphorylated NF-E2-related factor 2. Taken together, our data indicate that ROS are involved as key mediators in the early molecular events in the EMCP-induced apoptotic pathway.

• Journal of Life Science
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• v.29 no.9
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• pp.941-948
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• 2019

Colorectal cancer is a major health problem in industrialized countries. Ziyuglycoside II ($3{\beta}-3-{\alpha}$-1- arabinopyranosyloxy-19-hydroxyurs-12-en-28-oicacid), a triterpenoid saponin isolated from the roots of Sanguisorba officinalis L., possesses antioxidant, antiangiogenic, and anticancer properties. However, the therapeutic function of ziyuglycoside II in colitis-associated colorectal carcinogenesis is undefined. In the present study, the effect of ziyuglycoside II on colitis-associated colon cancer induced in mice using azoxymethane (AOM)/dextran sulfate sodium (DSS) was explored. The AOM model recapitulates many features of human colon cancer, but it lacks an inflammatory component. DSS induces colitis and promotes AOM-induced colon cancer in mice. BALB/c mice were injected with AOM and administered 2% DSS in drinking water. The mice were given ziyuglycoside II (1 or 5 mg/kg) orally three times per week, and colonic tissue was collected at 64 days. Administration of ziyuglycoside II markedly diminished the formation of colonic tumors. Western blot and immunohistological analyses showed that ziyuglycoside II noticeably decreased nuclear factor kappa-B-positive cells and levels of inflammation-related proteins, such as inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor-${\alpha}$, and interleukin-6 in colon tissue. It also prompted apoptosis. Ziyuglycoside II treatment augmented cleaved forms of caspase-3, caspase-7, and poly (ADP-ribose) polymerase in colonic tissues. In conclusion, ziyuglycoside II could defend against colitis-associated tumorigenesis in mice by inhibiting inflammation and inducing apoptosis. This shows a promising chemopreventive potential for its use in colitis-associated colon cancer.

• Journal of Microbiology and Biotechnology
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• v.33 no.5
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• pp.591-599
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• 2023

Fisetin is a bioactive flavonol molecule and has been shown to have antioxidant potential, but its efficacy has not been fully validated. The aim of the present study was to investigate the protective efficacy of fisetin on C2C12 murine myoblastjdusts under hydrogen peroxide (H₂O₂)-induced oxidative damage. The results revealed that fisetin significantly weakened H₂O₂-induced cell viability inhibition and DNA damage while blocking reactive oxygen species (ROS) generation. Fisetin also significantly alleviated cell cycle arrest by H₂O₂ treatment through by reversing the upregulation of p21WAF1/CIP1 expression and the downregulation of cyclin A and B levels. In addition, fisetin significantly blocked apoptosis induced by H₂O₂ through increasing the Bcl-2/Bax ratio and attenuating mitochondrial damage, which was accompanied by inactivation of caspase-3 and suppression of poly(ADP-ribose) polymerase cleavage. Furthermore, fisetin-induced nuclear translocation and phosphorylation of Nrf2 were related to the increased expression and activation of heme oxygenase-1 (HO-1) in H₂O₂-stimulated C2C12 myoblasts. However, the protective efficacy of fisetin on H₂O₂-mediated cytotoxicity, including cell cycle arrest, apoptosis and mitochondrial dysfunction, were greatly offset when HO-1 activity was artificially inhibited. Therefore, our results indicate that fisetin as an Nrf2 activator effectively abrogated oxidative stress-mediated damage in C2C12 myoblasts.