• Journal of the Korean Chemical Society
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• v.45 no.3
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• pp.264-267
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• 2001

• Genomics & Informatics
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• v.5 no.1
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• pp.32-35
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• 2007

Telomerase reverse transcriptase (TERT) is an enzymatic ribonucleoprotein that prolongs the replicative life span of cells by maintaining protective structures at the ends of eukaryotic chromosomes. Telomerase activity is highly up-regulated in 85-90% of human cancers, and is predominately regulated by hTERT expression. In contrast, most normal somatic tissues in humans express low or undetectable levels of telomerase activity. This expression profile identifies TERT as a potential anticancer target. By using an RNA mapping strategy based on a trans-splicing ribozyme library, we identified the regions of mouse TERT (mTERT) RNA that were accessible to ribozymes. We found that particularly accessible sites were present downstream of the AUG start codon. This mTERTspecific ribozyme will be useful for validation of the RNA replacement as cancer gene therapy approach in mouse model with syngeneic tumors.

• Molecules and Cells
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• v.24 no.3
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• pp.358-363
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• 2007

Swine endothelial cells are commonly used as an in vitro model for studying features of the blood-brain barrier and some hemorrhagic diseases. However, primary cultures of swine cells have finite lifespans. To establish immortalized swine umbilical vein endothelial cells (SUVECs) using human telomerase reverse transcriptase (hTERT), the plasmid pCI-neo-hTERT was transfected into SUVECs by lipofection. Clones were selected for G418 resistance, and positive clones were amplified. One of the clones was cultured for up to 50 passages. Factor VIII-related antigen and CD34 were detected. The immortalized cells shared the properties of normal cells, such as contact inhibition, serum requirement and anchorage dependence. Karyotype analysis revealed that the immortalized cells were in the diploid range. In addition, both in vivo and in vitro assays of tumorigenicity showed no neoplastic transformation. Furthermore, NO, $PGI_2$, and ET-1 concentrations in the transfected cells were normal. These results suggest that the SUVECs immortalized by hTERT retain their original characteristics.

• Journal of the Korean Applied Science and Technology
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• v.15 no.2
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• pp.1-9
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• 1998

The rate constants of hydrolysis of N-tert-butyl-${\alpha}$-phenylnitrone and its derivatives have been determined by UV spectrophotometry at $25^{\circ}C$ and a rate equation which can be applied over a wide pH range was obtained. On the basis of rate equations derived and judging from the hydrolysis products obtained and general base and substituent effects, plausible mechanism of hydrolysis in various pH range have been proposed. Below pH 4.5, the hydrolysis was initiated by the protonation and followed by the addition of water to ${\alpha}-carbon$. Above pH 10.0, the hydrolysis was proceeded by the addition of hydroxides ion to ${\alpha}-carbon$. In the range of 4.5${\sim}$10.0 the addition of water to nitrone was rate controlling step.

• YAKHAK HOEJI
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• v.46 no.5
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• pp.313-319
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• 2002

Synthesis of 7$\beta$-[(Z)-2-(2-aminothiazol-4-yl)-2-(1-carboxy-1-methylethoxyimino)acetamido]-3-[[(3S, 5S)-5-[4-phenyl-5-(4-methylphenyl or 2-thiophenyl)-4H-l, 2, 4- triazol-3-yl]thiomethylpyrrolidin-3-yl]]thiomethyl-3-cephem-4-carboxylic acids (7a, 7b) were described. (2S, 4S)-4-acethylthio-2-[4-phenyl-5-(4-methylphenyl or 2-thiophenyl)-4 H-1, 2, 4-triazol-3-yl]thiomethyl-1-tert-butoxycarbonylpyrrolidines (4a, 4b) were prepared from trans-4-hydroxy-L-proline with (2S, 4R)-absolute configuration as starting material. 4-Phenyl-5-(4-methylphenyl or 2-thiophenyl)-4 H-l, 2, 4-triazol-3-thiols (2a, 2b) were prepared from p-toluic anhydride and 2-thiophene carboxylic acid hydrazide, respectively. p-Methoxybenzyl 7$\beta$-(Z)-2-(2-for-mamidothiazol-4-yl)-2-(1-tert-butoxycarbonylisopropylimino]acetamido-3-[[ (3S, 5S)-5-[4-phenyl-5-(4-methylphenyl or 2-thio phenyl)-4H-1, 2, 3-triazol-3-yl]thiomethyl-1- tert-butoxycarbonylpyrrolidin-3-yl]]thiomethyl-3-cephem-4-carboxylates (6a, 6b) were achieved by using p-methoxybenzyl ]7P-(Z)-2-(2-formamidothiazol-4-yl)-2-(tert-butoxycarbonylisopropylimino] acetamido-3-chloromethyl-3-cephem-4-carboxylate (5) and (2S, 4S)-4-acethylthio-2-[4-phenyl-5-(4-methyl phenyl or 2-thiophenyl)-4H-1, 2, 4-triazol-3-yl]thiomethyl-1-tert-butoxycarbonyl pyrrolidines (4a, 4b). Removal of formyl, Boc, and p-methoxybenzyl protecting groups were carried out by triflu oroacetic acid and anisole to give the target compounds.

• Applied Chemistry for Engineering
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• v.19 no.4
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• pp.402-406
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• 2008

A series of random copolymers, composed of 1H,1H,2H,2H-perfluoro decyl methacrylate (FDMA) as a $CO_2$-philic monomer and tert-butyl methacrylate (TBMA) as an acid labile monomer, were synthesized by free radical polymerization. The solubility of copolymers in carbon dioxide, light sensitivity at 365 nm exposure, and photoresist pattern formation properties were investigated. Furthermore, sub micron-sized poly(styrenesulfonate) : poly(3,4-ethylenedioxythiophene) (PSS : PEDOT) conducting polymer patterns were successfully prepared by pattern transfer.

• Journal of dental hygiene science
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• v.21 no.4
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• pp.227-232
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• 2021

Background: Cancer-associated fibroblasts (CAFs) are abundant in tumor microenvironments and interact with cancer cells to promote tumor proliferation in oral squamous cell carcinoma (OSCC). Cathepsin D (CTSD) is a soluble lysosomal aspartic endopeptidase involved in tumor proliferation and angiogenesis. In this preliminary study, we observed CTSD expression in OSCC and CAFs, postulating that CTSD might act as a bridge between OSCC and CAFs. Methods: Human epidermal keratinocytes (HEKs), OSCC, and immortalized human normal oral fibroblasts (hTERT-hNOFs) were used in this study. Additionally, we used hTERT-hNOFs transfected with an empty vector, WT (wild-type)-YAP (Yes-associated protein), and YAPS127A (YAP serine 127 to alanine). YAP127A hTERT-hNOFs activated fibroblasts similar to CAFs. To identify CTSD expression between OSCC and CAFs, conditioned medium (CM) was collected from each cell. Protein expression of CTSD was identified by western blotting. Results: To identify the expression of CTSD in fibroblasts stimulated by OSCC, we treated fibroblasts with CM from HEK and OSCC. Results indicated that hTERT-hNOFs with OSCC CM showed a weakly increased expression of CTSD compared to stimulation by HEK CM. This indicates that CAFs, YAPS127 hTRET-hNOFs, overexpress CTSD protein. HEK cells showed no CTSD expression, regardless of treatment with fibroblast CM, whereas OSCC highly expressed CTSD proteins compared with the CTSD expression in HEK cells. We also found that CTSD expression was unaffected by changes in transforming growth factor-β levels. Conclusion: This study proposes that CTSD might have potential as an interacting executor between OSCC and CAFs. Further studies are needed to investigate the role of CTSD in tumor and stromal cells.

• Journal of Integrative Natural Science
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• v.6 no.2
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• pp.65-70
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• 2013

1,1-Bis(n-butyl)-2,3,4,5-tetraphenyl-1-silacyclopentadiene (3) and 1,1-bis(t-butyl)-2,3,4,5-tetraphenyl-1-silacyclopentadiene (4) are synthesized from the reaction of the versatile silole dianion (2) with n-butyl bromide and t-butyl bromide. Reduction of (3) and (4) with an excess of lithium to give 1,1-bis(n-butyl)-2,5-dilithio-2,3,4,5-tetraphenyl-1-silacyclopenta-3-enide (6) and 1,1-bis(t-butyl)-2,5-dilithio-2,3,4,5-tetraphenyl-1-silacyclopenta-3-enide (7). $^{13}C$-NMR study of two 2,5-carbodianions (6 and 7) shows tert-carbanion at 73.18 and 78.12 ppm respectively. Two bulky tert-butyl groups in (7) increase the inversion barrier at the tert-carbanion, line broadenings of tert-butyl groups in $^1H$ and $^{13}C$-NMR spectrum are observed.

• Molecules and Cells
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• v.26 no.5
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• pp.454-458
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• 2008

Sex steroid hormone receptors play a central role in modulating telomerase activity, especially in cancer cells. However, information on the regulation of steroid hormone receptors and their distinct functions on telomerase activity within the mesenchymal stem cell are largely unavailable due to low telomerase activity in the cell. In this study, the effects of estrogen ($E_2$) treatment and function of estrogen receptor alpha ($ER{\alpha}$) and estrogen receptor beta ($ER{\beta}$) on telomerase activity were investigated in human mesenchymal stem cells (hMSCs). Telomerase activity and mRNA expression of the catalytic subunit of telomerase (hTERT) were upregulated by treatment of the cells with $E_2$. The protein concentration of $ER{\alpha}$ was also increased by $E_2$ treatment, and enhancement of $ER{\alpha}$ accumulation in the nucleus was clearly detected with immunocytochemistry. When $ER{\alpha}$ expression was reduced by siRNA transfection into hMSCs, the effect of $E_2$ on the induction of hTERT expression and telomerase activity was diminished. In contrast, the transient overexpression of $ER{\alpha}$ increased the effect of $E_2$ on the expression of hTERT mRNA. These findings indicate that the activation of hTERT expression and telomerase activity by $E_2$ in hMSCs depends on $ER{\alpha}$, but not on $ER{\beta}$.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.4919-4923
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• 2014

Background: To investigate the effect of celecoxib on telomerase activity and apoptosis in a human laryngeal squamous carcinoma cell line (Hep-2 cells). Materials and Methods: The growth inhibition rate of Hep-2 cells in vitro was measured by MTT assay, and apoptosis by TUNEL assay and flow cytometry (FCM). The TRAP-ELISA method was used to determine telomerase activity in Hep-2 cells. The mRNA expression of human telomerase RNA component(hTR), human telomerase reverse transcriptase (hTERT) and human telomerase-associated protein(hTEP1) was determined by RT-PCR assay. Expression of Bax and Bcl-2 proteins was assessed by Western blotting. Results: Celecoxib can inhibit proliferation and induce apoptosis in a dose- and time-dependent manner, repress telomerase activity, decrease hTERT mRNA and Bcl-2 protein expression and increase Bax protein expression, PGE2 had no effect on telomerase. Conclusions: Celecoxib had the antiproliferative and pro-apoptotic effect in Hep-2 cells. Apoptosis was accompanied by a decrease in telomerase activity which was directly correlated with hTERT mRNA and up-regulation of Bax/Bcl-2. Bcl-2 may thus play an important role in telomerase activity as well as apoptosis.