• Asian Pacific Journal of Cancer Prevention
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• v.15 no.16
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• pp.6791-6798
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• 2014

Background: To investigate the effect of silibinin on proliferation and apoptosis in human gastric cancer cell line MGC803 and its possible mechanisms. Materials and Methods: Human gastric cancer cell line MGC803 cells were treated with various concentration of silibinin. Cellular viability was assessed by CCK-8 assay andapoptosis and cell cycle distribution by flow cytometry. Protein expression and mRNA of STAT3, and cell cycle and apoptosis regulated genes were detected by Western blotting and real-time polymerase chain reaction, respectively. Results: Silibinin inhibits growth of MGC803 cells in a dose- and time-dependent manner. Silibinin effectively induces apoptosis of MGC803 cells and arrests MGC803 cells in the G2/M phase of the cell cycle, while decreasing the protein expression of p-STAT3, and of STAT3 downstream target genes including Mcl-1, Bcl-xL, survivin at both protein and mRNA levels. In addition, silibinin caused an increase in caspase 3 and caspase 9 protein as well as mRNA levels. Silibinin caused G2/M phage arrest accompanied by a decrease in CDK1 and Cyclin B1 at protein and mRNA levels.. Conclusions: These results suggest that silibinin inhibits the proliferation of MGC803 cells, and it induces apoptosis and causes cell cycle arrest by down-regulating CDK1, cyclinB1, survivin, Bcl-xl, Mcl-1 and activating caspase 3 and caspase 9, potentially via the STAT3 pathway.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.329-332
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• 2002

We investigated the effect of Sarcodon aspratus extract on expression of cell cycle regulators. Methanol extract of Sarcodon aspratus showed a growth suppression on HepG2. As shown by western blot analysis, the expressions of cyclin A and Dl known as cell cycle regulators were decreased after treatment of Sarcodon aspratus extract. On the other hand, the expression of cyclin Bl was increased in the presence of Sarcodon aspratus extract. Furthermore, the expression of p53, a tumor supressor gene, and p27, a cell cycle dependent protein kinase inhibitor, were increased, whereas the expression of PCNA was decreased. In conclusion, our study suggests that growth inhibitory effect of Sardodon aspratus methanol extract on HepG2 is induced by cell cycle arrest in the Gl phase caused by decrease in cyclin A, Dl expressions and increases in p53, p27 expression.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.135-148
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• 2001

Gingival fibroblasts are major cellular component of gingiva. However, the molecular mechanisms of senescence of human gingival fibroblasts are unknown. Human fibroblasts undergo replicative senescence in vitro after a limited number of population doublings. A reduced rate of proliferation is a prominent phenomenon observed in senescent fibroblasts. This phenomenon is controled by cell cycle regulatory proteins. The purpose of present study was to investigate the effect of replicative senescence on cell cycle progression and to find out its molecular mechanisms in human gingival fibroblasts. Replicative senescence of gingival fibroblasts were induced by subsequent cultures that were repeated up to 18 passage. In the present study, I examined change of cell proliferation, cell activity, cell viability and cell cycle progression during the replicative process. Also, I examined expression of cell cycle regulatory proteins which was estimated by western blot analysis. Cell proliferation, cell activity and cell viability of gingival fibroblasts were notably decreased with increase of population doubling level(PDL). S phase was decreased and G1 phase was increased with increase of PDL. Western blot analysis showed that levels of P16, p21 and p53 of senescent gingival fibroblasts(PDL41, PDL58) were higher than young fibroblasts(PDL27) and cdk4 were lower than young fibroblasts(PDL27). In conclusion, these results suggest that proliferative function of human gingival fibroblasts may be decreased by replicative senescence and its molecular mechanisms may be activatied with p16, p21, p53 and pRB, and repressed wtih cdk4.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.3
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• pp.1043-1048
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• 2012

The COPS3 gene has stimulating effect on cell proliferation and progression of osteosarcomas and related cells. However, the features of COPS3 and its potential application as a therapeutic target in other cancers has not yet been studied. In this study, therefore, the effect of COPS3 silencing via COPS3 siRNA on lung cancer cell proliferation was examined. Expression levels of COPS3 gene in COPS3 siRNA infected cells and control siRNA infected cells were compared with real time PCR and Western blot analysis. Cell proliferation levels were comprehensively analyzed by MTT, BrdU incorporationy, and colony formation assays. For mechanistic assessment the effects of COPS3 silencing on cell cycle and apoptosis were analyzed using flow cytometry. Results showed that successful silencing of the COPS3 gene at both translational and transcriptional levels significantly reduced the proliferation and colony formation by lung cancer cells (p<0.01). Flow cytometry showed cell cycle arrest in the G0/G1 phase after COPS3 silencing, and more importantly, apoptosis was induced as a result of COPS3 knockdown, which negatively affected cell survival. Therefore, these results provide another piece of important evidence that the COPS3 gene expressed in lung cancer cells may play a critical role in stimulating proliferation. Down-regulation of COPS3 could significantly inhibit lung cancer cell growth, which was most likely mediated via induction of cell cycle arrest in G0/G1 phase and apoptosis.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.631-637
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• 2013

Luteolin is a naturally occurring flavonoid present in many plants with diverse applications in pharmacology. Despite several studies elucidating its significant anti-cancer activity against various cancer cells, the mechanism of action in skin cancer is not well addressed. Hence, we investigated the effects of luteolin in HaCaT (human immortalized keratinocytes) and A375 (human melanoma) cells. The radical scavenging abilities of luteolin were determined spectrophotometrically, prior to a cytotoxic study (XTT assay). Inhibitory effects were assessed by colony formation assay. Further, the capability of luteolin to induce cell cycle arrest and apoptosis were demonstrated by flow cytometry and cellular DNA fragmentation ELISA, respectively. The results revealed that luteolin possesses considerable cytotoxicity against both HaCaT and A375 cells with $IC_{50}$ values of 37.1 ${\mu}M$ and 115.1 ${\mu}M$, respectively. Luteolin also inhibited colony formation and induced apoptosis in a dose and time-dependent manner by disturbing cellular integrity as evident from morphological evaluation by Wright-Giemsa staining. Accumulation of cells in G2/M (0.83-8.14%) phase for HaCaT cells and G0/G1 (60.4-72.6%) phase for A375 cells after 24 h treatment indicated cell cycle arresting potential of this flavonoid. These data suggest that luteolin inhibits cell proliferation and promotes cell cycle arrest and apoptosis in skin cancer cells with possible involvement of programmed cell death, providing a substantial basis for it to be developed into a potent chemopreventive template for skin cancer.

• Journal of Periodontal and Implant Science
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• v.35 no.1
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• pp.87-98
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• 2005

The purpose of present study was to investigate the effects of physiologically active compound (SD62-122) from Phlomidis Radix on the cell cycle progression and its molecular mechanism in human gingival fibroblasts(HGFs). For this purpose, fibroblasts were isolated and cultured from excisioned gingiva during crown lengthening procedure in healthy adult. The following parameter were evaluated that there are cell number counting, MIT assay, cell cycle progression, western blot analysis. The cell number and MIT assay of primary cultured fibroblast was not increased at 2 days but significant increased compare to negative control at 3days(p<0.05). S phase was increased and G1 phase decreased in both $10^{-8}M$ and $10^{-9}M$ of SD62-122 in cell cycle analysis. The cell cycle regulation protein levels of Cyclin $D_1$, Cyclin E, cdk 2, cdk 4 and cdk 6 were increased compare to control in both $10^{-8}M$ and $10^{-9}M$ of SD62-122. The protein levels of p21 and p53 were decreased compare to control, but the level of pRb was not changed compare to control in $10^{-9}M$ of SD2-122. These results suggested that physiologically active compound (SD62-122) isolated from Phlomidis Radix increases the cell proliferation and cell cycle progression in HGFs, which is linked to increased cell cycle regulation protein levels of Cyclin $D_1$, Cyclin E, cdk 2, cdk 4 and cdk 6, and decreased the levels of p21, p53.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.913-918
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• 2005

Chloramphenicol is a broad-spectrum antimicrobial agent against Gram (+) and Gram (-) bacteria. Its clinical application has recently been limited, due to severe side effects such as bone marrow suppression and aplastic anemia. In the present study, the cytotoxic effects of chloramphenicol were investigated in vitro using chronic myelogenous leukemia K562 cells. Chloramphenicol inhibited the growth of K562 cells in a dose-dependent manner, but their growth was restored after the cessation of chloramphenicol, indicating reversible cytotoxic effects. The expression of cell cycle regulatory molecules, including E2F-1 and cyclin D1, was decreased at the translational and/or transcriptional level after being treated with a therapeutic blood level ($20{\mu}g/ml$) of chloramphenicol. Chloramphenicol also induced apoptotic cell death through a caspase-dependent pathway, which was verified by Western blot analysis and the enzymatic activity of caspase-3. These results demonstrated that chloramphenicol inhibited the cell growth through arresting the transition of the cell cycle, and induced apoptotic cell death through a caspase-dependent pathway at therapeutic concentrations.

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.279-285
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• 1994

The objective of the present study was to characterize the cell cycles of granulosa cell populations during follicular maturation in cattle by using flow cytometer. Granulosa cells were isolated from bovine preovulatory antral follicles of F1(>10mm), F2(5~20mm), F3(3~4mm) and F4(1~2mm) diameter and fixed and stained with fluorochromes that selectively bine to DNA. Flow cytometer equipped with a laser excitation system was used to analyze the intensity of fluorescence from stained cells. Forward angle light-scatter(FSC) and 90$^{\circ}$light-scatter(SSC) signals were adopted to measure the size and the granularity of granulosa cells. As a results of FSC/SSC analysis, granulosa cell populations(G1 phase of cell cycle) from each follicle were relatively regular in size and granularity, regardless of follicular size. However, their distribution in granularity was greater than that in size. Most of granulosa cell populations collected from each follicle were distributed in G0/G1, S and G2/M phases. As the follicles approached to ovulation the percentage of cells in the proliferative phases of cell cycle (S and G2/M) decreased significantly, but there was a concomitant increase in the percentage of granulosa cells in G1 phase. Therefore, these data indicate the proportion of main populations to cell cycle of granulosa cells may be changed from proliferative phase to G1 phase during follicular maturation in cattle.

• Biomolecules & Therapeutics
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• v.30 no.6
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• pp.576-584
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• 2022

Colorectal cancer is diagnosed as the third most prevalent cancer; thus, effective therapeutic agents are urgently required. In this study, we synthesized six homoisoflavane derivatives of cremastranone and investigated their cytotoxic effects on the human colorectal cancer cell lines HCT116 and LoVo. We further examined the related mechanisms of action using two of the potent compounds, SH-19027 and SHA-035. They substantially reduced the cell viability and proliferation in a dose-dependent manner. Treatment with SH-19027 and SHA-035 induced cell cycle arrest at the G2/M phase and increased expression of p21 both of which are implicated in cell cycle control. In addition, the apoptotic cell population and apoptosis-associated marker expression were accordingly increased. These results suggest that the synthesized cremastranone derivatives have anticancer effects through the suppression of cell proliferation and induction of apoptosis. Therefore, the synthesized cremastranone derivatives could be applied as novel therapeutic agents against colorectal cancer.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1312-1314
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• 1998

SOFC system is often subject to thermal cycle condition during normal start/stop, shutdown, and emergence state. Under the thermal cycle condition of heating and cooling, the SOFC components expand or shrink, which produces thermal stress and thermal shock. The SOFC performance is degraded by the thermal factors. To protect SOFC system from the thermal degradation, the optimum thermal condition must be clarified. In this study, to examine the thermal cycle characteristics, we fabricated single cells of planar SOFC with an area of $5{\times}5cm$. The electrolyte and PEN were tested under thermal cycle conditions in the range of$ 2-8^{\circ}C/min$. After thermal cycle test. crack creation of the components were examined using ultraviolet apparatus. No crack in the electrolyte and PEN were observed. The single cell system with alumina frame were also tested under thermal cycle conditions of 2, 3, $4^{\circ}C/min$. The single cell was fractured at the thermal cycle of 3 and $4^{\circ}C/min$ and the optimum condition of the thermal cycle to be found below $2^{\circ}C/min$.