• The Journal of Korean Medicine
• /
• v.20 no.1 s.37
• /
• pp.91-105
• /
• 1999

The effects of Yinjin and Yinjinsaryongsangagambang on a DNA damaging agent, etoposide-induced apoptosis, cell viability, cell cycle progression, and mRNA expression of apoptosis-related genes of human hepatocyte cell line HepG2 were investigated using tryphan blue exclusion assay, MTT assay, flow cytometry, immunocytometric analysis of PCNA, and quantitative RT-PCR analysis. MTT assay showed that Yinjin and Yinjinsaryongsangagambang increases cellular viability of HepG2 cells in a dosage-dependent manner. Stimulation of cell cycle progression by Yinjin or Yinjinsaryongsangagambang was detected by flow cytometric analysis of the DNA content and immunocytometric analysis of PCNA expression. A significant reduction of a DNA-damaging agent, etoposide-induced apoptosis were found in both Yinjin and Yinjinsaryongsangagambang-treated cells in dosage-dependent manner. In overall, 3-fold reduction of apoptosis was recognized in $10.0\;{\mu}g/ml$ of Yinjin or Yinjinsaryongsangagambang-treated cells compared to untreated cells. Although the difference is not significant, Yinjinsaryongsangagambang showed slightly higher effect on the inhibition of apoptosis than Yinjin. From flow cytometric analysis of apoptosis, while 39.9% of untreated cells showed etoposide-induced apoptotic cell death, only 19.6% or 17.4% of Yinjin or Yinjinsaryongsangagambang-treated cells were fond at apoptotic sub G1 phase, respectively. Interestingly, strong induction of Gadd45-mRNA was observed from Yinjin or Yinjinsaryongsangagambang-treated cells. However, no changes in expression levels of p53 and Waf1 were detected, demonstrating that induction of Gadd45 mRNA expression by Yinjin or Yinjinsaryongsangagambang occurs by p53-independent mechanism. Marked mRNA inductions of two apoptosis-inhibiting genes, Bcl-2 and Bcl- XL, were found in both Yinjin or Yinjinsaryongsangagambang-treated HepG2 cells while no changes was detected in expression levels of an apoptosis-promoting gene, Bax.

• BMB Reports
• /
• v.46 no.6
• /
• pp.289-294
• /
• 2013

To maintain cellular homeostasis against the demands of the extracellular environment, a precise regulation of kinases and phosphatases is essential. In cell cycle regulation mechanisms, activation of the cyclin-dependent kinase (CDK1) and cyclin B complex (CDK1:cyclin B) causes a remarkable change in protein phosphorylation. Activation of CDK1:cyclin B is regulated by two auto-amplification loops-CDK1:cyclin B activates Cdc25, its own activating phosphatase, and inhibits Wee1, its own inhibiting kinase. Recent biological evidence has revealed that the inhibition of its counteracting phosphatase activity also occurs, and it is parallel to CDK1:cyclin B activation during mitosis. Phosphatase regulation of mitotic kinases and their substrates is essential to ensure that the progression of the cell cycle is ordered. Outlining how the mutual control of kinases and phosphatases governs the localization and timing of cell division will give us a new understanding about cell cycle regulation.

• Journal of Ginseng Research
• /
• v.25 no.4
• /
• pp.156-161
• /
• 2001

We investigated the effects of polyacetylenes of ginseng on farnesyl protein transferase (FPTase) and carboxyl methyl transferase (CMTase) activities related to post-translational modification of Ras protein. We also investigated the effect of petroleum ether extract (PEE) of ginseng on progression of cell cycle. FPTase activity was respectively inhibited 16.2% by 10mM panaxynol and 21.3% by 10mM panaxydol, whereas CMTase activity was not inhibited by panaxynol or panaxydol. Treatment of PEE significantly reduced the numbers and size of human colon cancer cell (HT-29) and human liver cancer cell(HepG2) cultured, respectively. To investigate the mechanism of growth inhibition by PEE of ginseng, we analyzed the cell cycle progressions of PT-29 and HepG2 cells, respectively. We found that PEE significantly inhibited progression of cell cycle from G1 to S phase. These results suggest that anticancer effects of PEE were derived from the arrest of G1 phase in cell cycle progression.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.17 no.6
• /
• pp.1383-1392
• /
• 2003

Apoptosis is a morphologically and biochemically district form of cell death that occurs in many different cell types in a wide variety of organisms. Albizzia julibrissin belonging the family Leguminosae has been used for the treatment of contusion, sore throat, amnesia, and insomnia in oriental traditional medicine. This study investigates whether the water extract of A. julibrissin induce apoptotic cell death in Jurkat T-acute lymphoblastic leukemia (ALL) cells. Jurkat cells were increased inhibitions of cell viability in a concentration-dependent manner by A. julibrissin. This herbal medicine also caused apoptosis as measured by cell morphology and DNA fragmentation. The capability of A. julibrissin to induce apoptosis was associated with proteolytic cleavage of specific target proteins such as poly (ADP-ribose)polymerase (PARP) and beta-catenin proteins suggesting the possible involvement of caspases. Our result showed that Bcl-2 and Bax protein levels were not changed in all A. julibrissin-treated groups compared to control group. These results suggest that A. julibrissin-mediated apoptosis is independent with Bcl-2 related signaling pathway in this cells. The purpose of the present study is also to investigate the Effect of A. julibrissin on cell cycle progression. Our results showed that G1 checkpoint related gene products (cyclin D1, cyclin dependent kinase 4, retinoblastoma, E2F1) were decreased in their protein levels in a dose-dependent manners after treatment of the extract. These results indicate that the increase of apoptotic cell death by A. julibrissin may be due to the inhibition of cell cycle progression in wild type p53-lacking Jurkat cells.

• Environmental Mutagens and Carcinogens
• /
• v.24 no.1
• /
• pp.1-9
• /
• 2004

Three D-type cyelins (D1, D2, and D3) are expressed in G1 phase of the cell cyele and have been implicated in cell transformation and neoplasia in human and mouse. Cyclin D1 overexpression or amplification was described in various human cancers. However, there is controversy about the role of cyclin D2 in cell cyele progression and human carcinogenesis. Specially, loss of cyelin D2 is involved in a vital tumor suppressor function in normal breast tissue, and that its loss may be related to tumorigenesis. The author examined to effect over-expression of cyclin D2 on the cell proliferation, apoptosis, and cell cycle using cyclin D2 transfected stable T47D breast cancer cells to investigate whether cyclinD2 functions as a positive regulator or negative regulator in cell proliferation. Overexpression of cyclin D2 led to the suppression of cell growth in cyclin D2 transfected T47D in both in its expression level and a time dependent manner with up to 50% reduction of cell growth at 72 hours. Therefore, the authors performed the cell cycle phase analysis using the flow cytometry to investigate the effect of cyclin D2 on the cell cycle phase in cyclin D2 transfected stable T47D cells. The flow cytometry analysis revealed increased sub G0 phase in cyclin D2 transfeted cells up to 23% at 72 hours. To confirm these results induced by overexpression of cyclinD2, the apoptotic bodies were counted in control and cyclin D2 transfected T47 cells. There are markedly increases of apoptotic bodies in cyclin D2-transfected cells up to 18%. These results suggested that Cyclin D2 suppresses the cell proliferation in breast cancers cells via the induction of apotosis.

• The Journal of Korean Medicine
• /
• v.21 no.3
• /
• pp.174-185
• /
• 2000

Objectives : This study was carried out to evaluate the effects of five fractions on cell viability, cell cycle progression and apoptosis. Methods : This study employed MTT assay, Cell cycle analysis, Cpp32 protease assay, DNA fragmentation assay and Quantitative RT-PCR analysis. Results : In MTT assay, the butanol fraction of Injinsaryung-San has showed magnificent viability, while the $H_2O$ fraction and ethylacetate fraction also showed higher viability than the control group. The $H_2O$ fraction of Injinsaryung-San has showed magnificent viability, and butanol fraction and ethylacetate fraction of Injinsaryung-San with etoposide have also showed higher viability than the only etoposide group. Cell cycle analysis showed that each fraction of Injinsaryung-San had no significant effect on the cell cycle. DNA fragmentation assay showed that the butanol fraction, $H_2O$ fraction and ethylacetate fraction carried inhibitory effects on apoptosis induction. Cpp32 protease activity assay showed that the butanol fraction, $H_2O$ fraction and ethylacetate fraction decreased Cpp32 protease activity, with the butanol fraction displaying greater effects. Quantitative RT-PCR showed that the butanol fraction, $H_2O$ fraction and ethylacetate fraction suppressed Fas and Bax genes, the butanol fraction increased BcI-2 gene, however no effect on Cpp32. Conclusions : The data shows that the butanol fraction of Injinsaryung-San increases the hepatocyte viability and has the heptocelluar protective effect by the suppression of apoptosis through gene regulation.

• Journal of Microbiology and Biotechnology
• /
• v.13 no.6
• /
• pp.912-918
• /
• 2003

Mitotic centromere-associated kinesin (MCAK), which is a novel kinesin with a central motor domain, is believed to playa role in mitotic segregation of chromosome during the M phase of the cell cycle. In the present study, it is shown that a rabbit polyclonal antibody has been produced using the N-terminal region (187 aa) of human MCAK expressed in E. coli as the antigen. To express the N-terminal region in E. coli, the MCAK cDNA fragment encoding N-terminal 187 aa was obtained by PCR and was then inserted into the pET 3d expression vector. Molecular mass of the N-terminal region overexpressed in the presence of IPTG was 23.2 kDa on SDS-PAGE, and the protein was insoluble and mainly localized in the inclusion body that could be easily purified from the other cellular proteins. The N-terminal region was purified by electro-elution from the gel after the inclusion body was resolved on the SDS-PAGE. The antiserum obtained after tertiary immunization with the purified protein specifically recognized HsMCAK when subjected to Western blot analysis, and showed a fluctuation of the protein level during the cell cycle of human Jurkat T cells. Synchronization of the cell-cycle progression required for recovery of cells at a specific stage of the cell cycle was performed by either hydroxyurea or nocadazole, and subsequent release from each blocking at 2, 4, and 7 h. Northern and Western analyses revealed that both mRNA and protein of HsMCAK reached a maximum level in the S phase and declined to a basal level in the G1 phase. These results indicate that a polyclonal antibody raised against the N-terminal region (187 aa) of HsMCAK, overexpressed in E. coli, specifically detects HsMCAK (81 kDa), and it can analyze the differential expression of HsMCAK protein during the cell cycle.

• Molecules and Cells
• /
• v.39 no.9
• /
• pp.699-704
• /
• 2016

Developmentally regulated GTP-binding protein 2 (DRG2) plays an important role in cell growth. Here we explored the linkage between DRG2 and G2/M phase checkpoint function in cell cycle progression. We observed that knockdown of DRG2 in HeLa cells affected growth in a wound-healing assay, and tumorigenicity in nude mice xenografts. Flow cytometry assays and [$^3H$] incorporation assays indicated that G2/M phase arrest was responsible for the decreased proliferation of these cells. Knockdown of DRG2 elicited down-regulation of the major mitotic promoting factor, the cyclin B1/Cdk1 complex, but upregulation of the cell cycle arresting proteins, Wee1, Myt1, and p21. These findings identify a novel role of DRG2 in G2/M progression.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.244.1-244.1
• /
• 2002

Cyclooxygenase-2 ( COX-2 ) is an inducible enzyme which produces prostanoids by various stimuli. Overexpression of COX-2 in many tumor types indicates its association with tumor progression, which has been a promising target for chemoprevention and chemomodulation. We studied conc- and time-dependency of COX-2 inhibition, growth inhibition, and cell cycle arrest induced by celecoxib, a selective COX-2 inhibitor, in human non-small cell lung cancer (NSCLC) A549 cells. (omitted)

• The Journal of Internal Korean Medicine
• /
• v.26 no.1
• /
• pp.60-73
• /
• 2005

Objectives : The aim of this study was to evaluate the effects of Loranthus parasiticus Merr. on cell cycle and expression of related genes in HepG2 cells. Methods : The MTT assay, cell counting assay, $[^3H]-Thymidine$ incorporation assay, flow cytometric analysis, quantitative RT-PCR and western blot assay were studied. Results : In the water extract of Loranthus parasiticus Merr., inhibition of cell proliferation and DNA synthesis in HepG2 cells was seen. These inhibitory effects were due to inhibition of G l-S transition in cell cycle. After treatment with the extract, expression of cyclin D1(G1 check point related gene) was inhibited particularly in dose-dependent and time-dependent manners. Conclusion : These results suggest that the inhibition of cell cycle progression by Loranthus parasiticus Merr. in HepG2 cell is due to suppression of cyclin D1(G1 check point related gene) mRNA expression and protein synthesis.