• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.671-676
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• 2005

In this study, we investigated the antioxidant effect of extract from Monascus pillosus, on the human wild-type p53 and p21 expressing A549 lung epithelial cell line and MCF-7 mammary adenocarcinoma cell line stimulated by NO. $P21^{waf/cip1}$ was identified as a gene induced in senescent cells. It is a cyclin-dependent kinase inhibitor and has been shown to cause cell cycle arrest and apoptosis. While p53-regulated stimulation of p21 appears to be central for the permanent growth-arrest, the role of p21 in p53-triggered cell death is unclear. Low dose of sodium nitroprusside (SNP) induced the development of senescence associated with increased expression of p53 and p21 in A549 cells. Inhibition of p21 transactivating activity requires high level correlates with the amount of p53 necessary to cause cell death. Association of p21 and p53 results in inhibition of p21-stimulated transcription. This requires a higher p53 level than is necessary for transcriptional activation of endogenous p53-responsive gene but correlates well with the level of p53 necessary to cause cell death. Exposure to W-1 inhibited oxidative stresses-induced senescence-like arrest, resulting in a significant reduction in p53 and p21 steady state levels. These results suggest that p53 and p21 play a central role in the onset of senescence. Thus, it is important to emphasize control of oxidative balance in tumor prevention and aging.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.1-6
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• 2004

$\beta$-Sitosterol is the major phytosterol in higher plants, including fruits and vegetables. The molecule has been shown to have the potential for prevention and therapy for human cancer. We investigated the effects of $\beta$-sitosterol on the cell proliferation of HCT116 human colon cancer cells in order to understand its anti-proliferative mechanism. $\beta$-Sitosterol treatment resulted in the inhibition of cell proliferation in a concentration-dependent manner. The anti-proliferative effect of HCT116 cells by $\beta$-sitosterol was associated with formation of apoptotic bodies and degradation of $\beta$-catenin protein. In addition, $\beta$-sitosterol-treatment induced a marked accumulation of tumor suppressor p53 and a concomitant induction of cyclin-dependent kinase (Cdk) inhibitor p21 without alteration in the levels of cyclins and Cdks. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-cancer activity of $\beta$-sitosterol.

• Molecules and Cells
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• v.21 no.1
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• pp.42-51
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• 2006

We investigated the mechanism of contraction induced by S1P in esophageal smooth muscle cells. Western blot analysis demonstrated that $S1P_1$, $S1P_2$, $S1P_3$, and $S1P_5$ receptors existed in the cat esophagus. Only penetration of EDG-5 ($S1P_2$) antibody into permeabilized cells inhibited S1P-induced contraction. Pertussis toxin (PTX) also inhibited contraction, suggesting that it was mediated by $S1P_2$ receptors coupled to a PTXsensitive $G_i$ protein. Specific antibodies to $G_{i2}$, $G_q$ and $G_{\beta}$ inhibited contraction, implying that the S1P-induced contraction depends on PTX-insensitive $G_q$ and $G_{\beta}$ dimers as well as the PTX-sensitive $G_{i2}$. Contraction was not affected by the phospholipase $A_2$ inhibitor DEDA, or the PLD inhibitor ${\rho}$-chloromercuribenzoate, but it was abolished by the PLC inhibitor U73122. Incubation of permeabilized cells with $PLC{\beta}3$ antibody also inhibited contraction. Contraction involved the activation of a PKC pathway since it was affected by GF109203X and chelerythrine. Since $PKC{\varepsilon}$ antibody inhibited contraction, $PKC{\varepsilon}$ may be required. Preincubation of the muscle cells with the MEK inhibitor PD98059 blocked S1P-induced contraction, but the p38 MAP kinase inhibitor SB202190 did not. In addition, co-treatment of cells with GF 109203X and PD98059 did not have a synergistic effect, suggesting that these two kinases are involved in the same signaling pathway. Our data suggest that S1P-induced contraction in esophageal smooth muscle cells is mediated by $S1P_2$ receptors coupled to PTX-sensitive $G_{i2}$ proteins, and PTX-insensitive $G_q$ and $G_{\beta}$ proteins, and that the resulting activation of the $PLC{\beta}3$ and $PKC{\varepsilon}$ pathway leads to activation of a p44/p42 MAPK pathway.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.2
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• pp.161-168
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• 2016

Abnormal localization of tumor suppressor proteins is a common feature of renal cancer. Nuclear export of these tumor suppressor proteins is mediated by chromosome region maintenance-1 (CRM1). Here, we investigated the antitumor effects of a novel reversible inhibitor of CRM1 on renal cancer cells. We found that S109 inhibits the CRM1-mediated nuclear export of RanBP1 and reduces protein levels of CRM1. Furthermore, the inhibitory effects of S109 on CRM1 is reversible. Our data demonstrated that S109 significantly inhibits proliferation and colony formation of renal cancer cells. Cell cycle assay showed that S109 induced G1-phase arrest, followed by the reduction of Cyclin D1 and increased expression of p53 and p21. We also found that S109 induces nuclear accumulation of tumor suppressor proteins, Foxo1 and p27. Most importantly, mutation of CRM1 at Cys528 position abolished the effects of S109. Taken together, our results indicate that CRM1 is a therapeutic target in renal cancer and the novel reversible CRM1 inhibitor S109 can act as a promising candidate for renal cancer therapy.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.6
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• pp.1177-1183
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• 2002

We investigated the effects of Sabaek-san (SBS) water extract on the cell proliferation of human lung carcinoma A549 cells. SBS treatment resulted in the inhibition of cell proliferation in a concentration-dependent manner. This anti-proliferative effect of A549 cells by SBS treatment was associated with morphological changes such as membrane shrinking and cell rounding up. DNA flow cytometric histograms showed that population of G1 phase of the cell cycle was increased by SBS treatment in a concentration-dependent manner. SBS treatment induced a marked accumulation of tumor suppressor p53 and a concomitant induction of cyclin-dependent kinase (Cdk) inhibitor p21WAF1/CIP, which appears to be transcriptionally upregulated and is p53 dependent. In addition, SBS treatment resulted in down-regulation of cyclooxygenase-2 (COX-2) as determined by RT-PCR analysis. The present results indicated that SBS-induced inhibition of lung cancer cell proliferation is associated with the blockage of G1/S progression the induction of apoptosis.

• Molecules and Cells
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• v.26 no.4
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• pp.396-403
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• 2008

The first ORF of the ARV S1133 S1 segment encodes the nonstructural protein p10, which is responsible for the induction of cell syncytium formation. However, p10-dependent signaling during syncytium formation is fully unknown. Here, we show that dominant negative RhoA, Rho inhibitor C3 exoenzyme, ROCK/Rho-kinase inhibitor Y-27632 and Rac1 inhibitor NSC23766 inhibit p10-mediated cell fusion. p10 over-expression is concomitant with activation and membrane translocation of RhoA and Rac1, but not cdc42. RhoA and Rac1 downstream events, including JNK phosphorylation and transcription factor AP-1 and $NF-{\kappa}B$ activation, as well as MLC expression and phosphorylation are simultaneously activated by p10. p10 point mutant T13M possessed 20% fusion-inducing ability and four p10 fusion-deficient mutants V15M, V19M, C21S and L32A reduced or lost their ability to activate RhoA and Rac1 signaling. We conclude that p10-mediated syncytium formation proceeds by utilizing RhoA and Rac1-dependent signaling.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.2
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• pp.553-560
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• 2004

In the present study, we investigated the anti-proliferative effects of aqueous extract of Wikyung-tang(WKT) on the growth of human lung carcinoma cell line A549. WKT treatment declined the cell viability and proliferation of A549 cells in a concentration-dependent manner. The anti-proliferative effects by WKT treatment in A549 cells was associated with morphological changes such as membrane shrinking and cell rounding up. WKT treatment induced an inhibition and/or degradation of apoptotic target proteins such poly(ADP-ribose) polymerase (PARP) and phospholipase C-γ1 (PLC-γ1). WKT treatment did not affect the levels of other Bcl-2 family gene products, such as Bcl-2, Bax and Bad. Western blot analysis and RT-PCT data revealed that the levels of tumor suppressor p53 and cyclin-dependent kinase inhibitor p21 were induced by WKT treatment in A549 cells. Additionally, WKT treatment induced the down-regulation of telomerase reverse transcriptase mRNA (hTERT) expression of A549 cells, however, the levels of other telomere-regulatory gene products were not affected. Taken together, these findings suggest that WKT-induced inhibition of human lung cancer cell proliferation is associated with the induction of apoptotic cell death via regulation of several major growth regulatory gene products and WKT may have therapeutic potential in human lung cancer.

• International Journal of Molecular Medicine
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• v.46 no.5
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• pp.1923-1937
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• 2020

It has been suggested that oxidative stress involving reactive oxygen species (ROS) induces granulosa cell apoptosis, leading to follicular atresia, and that T-lymphokine-activated killer cell-originated protein kinase (TOPK) suppresses cancer cell apoptosis induced by several stimuli. However, it remains to be determined whether TOPK affects oxidative stress-induced granulosa cell apoptosis. The present study demonstrates that TOPK inhibition increases human granulosa COV434 cell apoptosis induced by hydrogen peroxide (H₂O₂). Co-treatment with the TOPK inhibitor, OTS514, in combination with H₂O₂ increased p53 acetylation and its expression, whereas it decreased Sirtuin 1 (SIRT1) expression, contributing to the promotion of apoptosis. In addition, the SIRT1 activator, resveratrol, or the SIRT1 inhibitor, Ex527, reduced or elevated H₂O₂-induced COV434 cell apoptosis, respectively. Furthermore, the p53 inhibitor, Pifithrin-μ, diminished the augmentation in poly(ADP-ribose) polymerase (PARP) cleavage induced by OTS514 plus H₂O₂, while the Mdm2 antagonist, Nutlin 3, increased PARP cleavage. Moreover, OTS514 further decreased the SIRT1 transcriptional activity decreased by H₂O₂, but promoted the H₂O₂-induced p53 or p21 transcriptional activity. Notably, the expression of exogenous p53 reduced SIRT1 transcriptional activity. Taken together, the findings of the present study demonstrate that TOPK inhibition promotes p53-mediated granulosa cell apoptosis through SIRT1 downregulation in response to H₂O₂. Therefore, it can be concluded that TOPK suppresses H₂O₂-induced apoptosis through the modulation of the p53/SIRT1 axis, suggesting a potential role of TOPK in the regulation of human granulosa cell apoptosis, leading to the promotion of abnormal follicular development.

• BMB Reports
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• v.29 no.4
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• pp.380-385
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• 1996

Ovomucoid third domain is a serine proteinase inhibitor protein which consists of 56 amino acid residues. A fifty picosecond molecular dynamics (MD) simulation was carried out for ovomucoid third domain protein with 5 $\AA$ layer of water molecules. A comparison of main chain atoms in the MD averaged structure with the crystal structure showed that most of the backbone structures are maintained during the simulation. Investigation of the intramolecular hydrogen bondings indicated that most of the interactions between main chain atoms were conserved, whereas those between side chains were reorganized for the period of the simulation. Especially, the side chain interactions around the scissile bond of reactive site P1 (Met18) were found to be more extensive for the MD structures. During the simulation, hydrogen bonds were maintained between the side chains of Glu19 and Arg21 as well as those of Thr17 and Glu19. Extensive side chain interactions observed in the MD structures may shed light on the question of why protein proteinase inhibitors are strong inhibitors for proteinases rather than good substrates.

• 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.