• Journal of Life Science
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• v.28 no.9
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• pp.1016-1021
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• 2018

Clostridium difficile toxin A causes pseudomembranous colitis. The pathogenesis of toxin A-induced colonic inflammation includes toxin A-dependent epithelial cell apoptosis, resulting in the loss of barrier function provided by epithelial cells against luminal pathogens. Toxin A-dependent epithelial cell apoptosis has been linked to toxin A-induced production of reaction oxygen species and subsequent p38MAPK activation; $p21^{CIP1/WAF1}$ upregulation-dependent cell cycle arrest; cytoskeletal disaggregation; and/or the induction of Fas ligand on epithelial cells. However, the molecular mechanisms underlying toxin A-induced apoptosis remain poorly understood. This study tested whether toxin A could block the Wnt signaling pathway, which is involved in gut epithelial cell proliferation, differentiation and antiapoptotic progression. Toxin A treatment of nontransformed human colonocytes (NCM460) rapidly reduced ${\beta}$-catenin protein, an essential component of the Wnt signaling pathway. Exposure of mouse ileum to toxin A also significantly reduced ${\beta}$-catenin protein levels. MG132 inhibition of proteasome-dependent protein degradation resulted in the recovery of toxin A-mediated reduction of ${\beta}$-catenin, indicating that toxin A may activate intracellular processes, such as $GSK3{\beta}$, to promote degradation of ${\beta}$-catenin. Immunoblot analysis showed that toxin A increased active phosphorylation of $GSK3{\beta}$. Because the Wnt signaling pathway is essential for gut epithelial cell proliferation and anti-apoptotic processes, our results suggest that toxin A-mediated inhibition of the Wnt signaling pathway may be required for maximal toxin A-induced apoptosis of gut epithelial cells.

• Biomolecules & Therapeutics
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• v.17 no.4
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• pp.403-411
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• 2009

Thiacremonone, the main component isolated from heated garlic (Allium sativum L.), is interested for using as a cancer preventive or therapeutic agent since garlic has been known to be useful plant in the treatment of cancers. Nuclear factor kappaB (NF-${\kappa}B$) is constitutively activated in the prostate cancer and activation of NF-${\kappa}B$ is implicated in drug resistance in cancer cells. Docetaxel, a semisynthetic analog of paclitaxel, is an antineoplastic drug widely used for advanced various cancer. In previous studies, we found that thiacremonone inhibited activation of NF-${\kappa}B$ in cancer cells and marcrophages. In the present study, we investigated whether thiacremonone could increase susceptibility of prostate cancer cells (PC-3 and DU145) to docetaxel via inactivation of NF-${\kappa}B$. We found that the combination treatment of thiacremonone (50 ${\mu}g$/ml) with docetaxel (5 nM) was more effective in the inhibition of prostate cancer cell growth and induction of apoptosis accompanied with the significant inhibition of NF-${\kappa}B$ activity than those by the treatment of thiacremonone or docetaxel alone. It was also found that NF-${\kappa}B$ target gene expression of Bax, caspase-3 and caspase-9 was much more significantly enhanced, but the expression of Bcl-2 was also much more significantly inhibited by the combination treatment. These results indicate that thiacremonone inhibits NF-${\kappa}B$, and enhances the susceptibility of prostate cancer cells to docetaxel. Thus, thiacremonone could be useful as an adjuvant anti-cancer agent.

• Korean Journal of Head & Neck Oncology
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• v.18 no.2
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• pp.142-149
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• 2002

Objectve : Okadaic acid is a specific inhibitor of serine/threonine protein phosphatase 1 and 2A. In order to know the mechanism of apoptosis induced by okadaic acid, we treated FRTL-5 thyroid cells with okadaic acid and measured the changes of important proteins that are involved in apoptosis. Materials and Methods: We measured caspase 3 activity, $PLC-{\gamma}1$ degradation, the expression of XIAP, cIAP1, cIAP2, and cytochrome c release in okadaic acid-treated FRTL-5 thyroid cells. Results: Okadaic acid-induced caspase 3 activation and $PLC-{\gamma}1$ degradation and apoptosis were dose-dependent with a maximal effect at a concentration of 80 nmol and time-dependent with a maximal effect at 24 hours after treatment. The elevated caspase 3 activity in okadaic acid treated FRTL-5 thyroid cells are correlated with down-regulation of XIAP and cIAP1, but not cIAP2. General and potent inhibitor of caspases, z-VAD-fmk. abolished okadaic acid-induced caspase 3 activity and $PLC-{\gamma}1$ degradation. The release of cytochrome c in okadaic acid-induced FRTL-5 thyroid cells was dose-dependent with a maximal effect at a concentration of 80 nmol. Conclusions: These findings suggest that mechanism of okadaic acid-induced apoptosis is associated with cytochrome c release and increase of caspase 3 activation in FRTL-5 thyroid cells.

• Journal of Life Science
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• v.14 no.3
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• pp.445-452
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• 2004

We investigated the cytotoxic effects of seven furanoterpenoids 〔sarcotin A, epi-sarcotin A, ircinin-1, epi-sarcotrine B, sarcotin I, (8E, l3Z, 20Z)-strobilinin/(7E,l3Z, 20Z)-felixinin and (7E,12E,18R,20Z)-variabilin〕 isolated from the sponge Sarcotragus sp. (the order Dictyoceratida) on the growth of A549 human lung carcinoma cells. MTT data revealed that sarcotin A and (7E,12E,18R,20Z)-variabilin exhibited higher potencies on the anti-proliferative activities than the other compounds in A549 cells. The growth inhibition by treatment with compounds (especially epi-sarcotin A, ircinin-1 and epi-sarcotrine B) were associated with the induction of apoptotic cell death through the concentration-dependent increase of Bax/Bcl-2 ratio in a p53-dependent or independent pathway Additionally, epi-sarcotin A and ircinin-1 strongly inhibited the levels of cyclooxygenase (COX)-2 expression without alteration of COX-1. Taken together, the results suggest that the furanoterpenoids from the marine sponge have strong potentials as candidates for anti-cancer drugs.

• Journal of Life Science
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• v.15 no.5 s.72
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• pp.726-733
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• 2005

Histone deacetylase (HDAC) inhibitors target key steps of tumor development. They inhibit proliferation, induce differentiation and/or apoptotic cell death, and exhibit potent antimetastatic and antiangiogenic properties in cancer cells in vitro and in vivo. Although they are emerging as a promising new treatment strategy in malignancy, how they exert their effect on human non-small cell lung cancer cells is as yet unclear. The present study was undertaken to investiate the underlying mechanism of a HDAC inhibitor trichostatin A (TSA)-induced growth arrest and its effect on the cell cycle control gene products in a human lung carcinoma cell line A549. TSA treaoent induced the growth inhibition and morphological changes in a concentration-dependent manner. Treatment of A549 cells with TSA resulted in a concentration-dependent increased G1 (under 100 ng/ml) and/or G2/M (200 ng/ml) cell population of the cell cycle as determined by flow cytometry Moreover, 200 ng/ml TSA treatment significantly induced the population of sub-G1 cells (23.0 fold of control). This anti-proliferative effect of TSA was accompanied by a marked inhibition of cyclins, positive regulators of cell cycle progression, and cyclin-dependent kinases (Cdks) expression and concomitant induction of tumor suppressor p53 and Cdk inhibitors such as p21 and p27 Although further studies are needed, these findings provide important insights into the possible molecular mechanisms of the anti-cancer activity of TSA in human lung carcinoma cells.

• Journal of Dental Anesthesia and Pain Medicine
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• v.16 no.4
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• pp.263-271
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• 2016

Background: Bone injury is common in many clinical situations, such as surgery or trauma. During surgery, excessive reactive oxygen species (ROS) production decreases the quality and quantity of osteoblasts. Remifentanil decreases ROS production, reducing oxidative stress and the inflammatory response. We investigated remifentanil's protective effects against $H_2O_2$-induced oxidative stress in osteoblasts. Methods: To investigate the effect of remifentanil on human fetal osteoblast (hFOB) cells, the cells were incubated with 1 ng/ml of remifentanil for 2 h before exposure to $H_2O_2$. For induction of oxidative stress, hFOB cells were then treated with $200{\mu}M$ $H_2O_2$ for 2 h. To evaluate the effect on autophagy, a separate group of cells were incubated with 1 mM 3-methyladenine (3-MA) before treatment with remifentanil and $H_2O_2$. Cell viability and apoptotic cell death were determined via MTT assay and Hoechst staining, respectively. Mineralized matrix formation was visualized using alizarin red S staining. Western blot analysis was used to determine the expression levels of bone-related genes. Results: Cell viability and mineralized matrix formation increased on remifentanil pretreatment before exposure to $H_2O_2$-induced oxidative stress. As determined via western blot analysis, remifentanil pretreatment increased the expression of bone-related genes (Col I, BMP-2, osterix, and $TGF-{\beta}$). However, pretreatment with 3-MA before exposure to remifentanil and $H_2O_2$ inhibited remifentanil's protective effects on hFOB cells during oxidative stress. Conclusions: We showed that remifentanil prevents oxidative damage in hFOB cells via a mechanism that may be highly related to autophagy. Further clinical studies are required to investigate its potential as a therapeutic agent.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.10
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• pp.1422-1429
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• 2016

Kombucha is a slightly sour beverage fermented by symbiotic micro-organisms, including bacteria and yeasts. In this study, we examined the biological activities of citrus Kombucha (CK) produced by addition of citrus extract to original Kombucha (K). After fermentation for 10 days, radical scavenging activity examined by ABTS and DPPH assays increased by approximately 20% compared to that of K. Moreover, content of total phenolic compounds significantly increased by 60% compared to that of K. Cell proliferation assays utilizing MTT showed that CK treatment significantly inhibited growth of bladder cancer cells, T-24 and 5637, in a dose-dependent manner with $IC_{50}$ values of 4 and 7 mg/mL, respectively. Annexin V staining showed that CK treatment led to apoptosis of cells in a dose-dependent manner. T-24 cells were more sensitive to CK treatment than 5637 cells, as 8 mg/mL of CK resulted in 97% apoptosis of T-24 cells. Western blotting showed that CK treatment led to up-regulation of apoptotic proteins, including caspases-3, -8, -9, and PARP, in bladder cells not in K-treated cells. Taken together, these results demonstrate that CK may be developed as a functional beverage.

• Journal of Life Science
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• v.24 no.11
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• pp.1244-1251
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• 2014

Platycodon grandiflorum (PG) has been known to possess many biological effects, including anti-inflammatory and anti-allergy activity and anti-obesity and hyperlipidemia effects. However, little research has been conducted regarding its anticancer effects, with the exception of its ability to stimulate apoptosis in skin cells. There has also been no study regarding PG-induced autophagy. The modulation of autophagy is recognized as one of the hallmarks of cancer cells. Depending on the type of cancer and the context, autophagy can suppress or help cancer cells to overcome metabolic stress and the cytotoxicity of chemotherapy. Therefore, the present study was designed to investigate whether or not extracts from PG-induced cell death were connected with autophagy and apoptosis in HCT-116 human colon cancer cells. PG stimulation decreased cell proliferation in a dose- and time-dependent manner and induced apoptosis, which was partially dependent on the activation of caspases. PG treatment also resulted in the formation of autophagic vacuoles simultaneously with regulation of autophagy-related genes. Interestingly, a PG-mediated apoptotic effect was further triggered by pretreatment with the autophagy inhibitors 3-methyladenin and bafilomycin A1. However, cell viability recovered quite well with bafilomycin A1 treatment. These findings show that PG treatment promotes both autophagy and apoptosis and that PG-induced autophagic response might play a role in the autophagic cell death of HCT-116 cells.

• Journal of Life Science
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• v.27 no.1
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• pp.1-7
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• 2017

Abnormal actin remodeling is a typical characteristic of tumor cells. Thymosin ${\beta}_{10}$ (TB10) and profilin-1 (PFN-1) are actin-binding proteins and essential regulators of actin polymerization. We previously showed that TB10 induced death in ovarian cancer cells by sequestering F-actin, but the underlying mechanisms of this induction have not been explored. In this study, we identified TB10 as a novel regulator of PFN-1 and demonstrated its novel function as a tumor suppressor in ovarian cancer cell lines. The present study investigated protein expression profiles through polyacrylamide gel electrophoresis (PAGE) and liquid chromatography-mass spectroscopy (LC-MS/MS) in SKOV3 cells, an ovarian cancer cell line, that were transiently transfected with TB10. PFN-1 was highly overexpressed in response to TB10, and overexpression of PFN-1 resulted in inhibition of cell proliferation and migration and promotion of cellular apoptosis in ovarian cancer cells. Furthermore, transiently transfected PFN-1 appeared to deactivate the Erk signaling pathway, followed by decreased expression of Elk-1 and Egr-1 in human ovarian cancer cells. Interestingly, PFN-1 did not affect the activation of Akt. The results demonstrated that PFN-1 induced apoptotic cell death and inhibited proliferation and migration in ovarian cancer cells, suggesting that PFN-1 may be valuable in anti-cancer therapy.

• Biomolecules & Therapeutics
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• v.28 no.2
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• pp.202-210
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• 2020

Fluoxetine is used widely as an antidepressant for the treatment of cancer-related depression, but has been reported to also have anti-cancer activity. In this study, we investigated the cytotoxicity of fluoxetine to human gastric adenocarcinoma cells; as shown by the MTT assay, fluoxetine induced cell death. Subsequently, cells were treated with 10 or 20 µM fluoxetine for 24 h and analyzed. Apoptosis was confirmed by the increased number of early apoptotic cells, shown by Annexin V- propidium iodide staining. Nuclear condensation was visualized by DAPI staining. A significant increase in the expression of cleaved PARP was observed by western blotting. The pan-caspase inhibitor Z-VAD-FMK was used to detect the extent of caspase-dependent cell death. The induction of autophagy was determined by the formation of acidic vesicular organelles (AVOs), which was visualized by acridine orange staining, and the increased expression of autophagy markers, such as LC3B, Beclin 1, and p62/SQSTM 1, observed by western blotting. The expression of upstream proteins, such as p-Akt and p-mTOR, were decreased. Autophagic degradation was evaluated by using bafilomycin, an inhibitor of late-stage autophagy. Bafilomycin did not significantly enhance LC3B expression induced by fluoxetine, which suggested autophagic degradation was impaired. In addition, the co-administration of the autophagy inhibitor 3-methyladenine and fluoxetine significantly increased fluoxetine-induced apoptosis, with decreased p-Akt and markedly increased death receptor 4 and 5 expression. Our results suggested that fluoxetine simultaneously induced both protective autophagy and apoptosis and that the inhibition of autophagy enhanced fluoxetine-induced apoptosis through increased death receptor expression.