• Asian Pacific Journal of Cancer Prevention
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• 제14권6호
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• pp.3449-3453
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• 2013

Background: Telomerase has been considered as an attractive molecular target for breast cancer therapy. The main objective of this work is to assess the inhibitory effects of silibinin and curcumin, two herbal substances, on telomerase gene expression in breast cancer cells. Materials and Methods: For determination of cell viability tetrazolium-based assays were conducted after 24, 48, and 72 h exposure times and expression of human telomerase reverse transcriptase gene was measured with real-time PCR. Results: Each compound exerted cytotoxic effects on T47D cells and inhibited telomerase gene expression, both in a time-and dose-dependent manner. The mixture of curcumin and silibinin showed relatively more inhibitory effect on growth of T47D cells and hTERT gene expression as compared with either agent alone. Conclusions: These findings suggest that cell viability along with hTERT gene expression in breast cancer cells could be reduced by curcumin and silibinin.

• 한방안이비인후피부과학회지
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• 제19권2호
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• pp.26-39
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• 2006

Objective : The effect of water extract of Chungjogupae-tang (CJGPT) was investigated on the growth of human lung carcinoma A549 cells. Methods : MTT assay and fluorescent microscope performed to compare and examine the efficacy of CJGPT treatment on the cytostaticity of lung cancer cells in proportion to time and doses, and DAPI staining and Western blot analysis were used to examine their effect on apoptosis. In addition the quantitative RT-PCR was used to examine to lung cancer cells growth and Progtaglandin E2 and Telomerase activity were measured Results : Exposure of A549 cells to CJGPT resulted in the growth inhibition and apoptosis in a dose-dependent manner as measured by MTT assay and fluorescent microscope. The antiuoliferative effect by CJGPT treatment in A549 cells was associated with morphological changes such as membrane shrinking and cell rounding up. CJGPT treatment resulted in an up-regulation of cyclin-dependent kinase inhibitor p21(WAF1/CIPl) in a p53-independent fashion. We found that CJGPT treatment decreased the levels of cyclooxygenase (COX)-2 and inducible nitric oxide synthease (iNOS) expression without significant changes in the expression of COX-1, which was correlated with a decrease in protaglandin E2 (PGE2) synthesis. CJGPT treatment also inhibited the levels of human telomerase reverse transcriptase (hTERT) and telomerase-associated protein (TEP)-1 mRNA expression, however the activity of telomerase was slightly increased by CJGPT treatment. Conclusion : These findings suggested that CJGPT-induced inhibition of human lung carcinoma A549 cell growth was connected with the induction of apoptotic cell death and the results provided important new insights into the possible molecular mechanisms of the anti-cancer activity of CJGPT.

• 한국해양바이오학회지
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• 제1권4호
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• pp.243-251
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• 2006

Dideoxypetrosynol A, a polyacetylene from the marine sponge Petrosia sp., is known to exhibit significant selective cytotoxic activity against a small panel of human tumor cell lines, however, the mechanisms of which are poorly understood. In the present study, it was investigated the further possible mechanisms by which dideoxytetrosynol A exerts its anti-proliferative action in cultured human leukemia cell line U937. We observed that the proliferation-inhibitory effect of dideoxypetrosynol A was due to the induction of G1 arrest of the cell cycle and apoptosis, which effects were associated with up-regulation of cyclin D1 and down-regulation of cyclin E without any change in cyclin-dependent-kinases (Cdks) expression. Dideoxypetrosynol A markedly induced the levels of Cdk inhibitor p16/INK4a expression. Furthermore, down-regulation of phosphorylation of retinoblastoma protein (pRB) by this compound was associated with enhanced binding of pRB and the transcription factor E2F-1. The increase in apoptosis was associated with a dose-dependent up-regulation in pro-apoptotic Bax expression and activation of caspase-3 and caspase-9. Dideoxytetrosynol A decreased the levels of cyclooxygenase (COX)-2 mRNA and protein expression without significant changes in the levels of COX-1, which was correlated with a decrease in prostaglandin E2 (PGE2) synthesis. Furthermore, dideoxytetrosynol A treatment markedly inhibited the activity of telomerase, and the expression of human telomerase reverse transcriptase (hTERT), a main determinant of the telomerase enzymatic activity, was progressively down-regulated by dideoxytetrosynol A treatment in a dose-dependent fashion. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-cancer activity of dideoxytetrosynol A.

• Archives of Pharmacal Research
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• 제28권3호
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• pp.351-357
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• 2005

Endosulfan is one of the organochlorine pesticides, which are well-known endocrine disruptors (EDs), and it acts as an estrogen agonist. Estrogen is a group of hormones that play an important role in mammary gland function and are implicated in mammary carcinogenesis. In the present study, we studied the effects of endosulfan on nodule like alveolar lesion (NLAL) formation in mouse mammary gland development using a mouse mammary gland organ culture (MMOC) system. Although endosulfan-treated mammary glands did not form NLALs, more alveolar buds were formed in this group than in the negative control (vehicle-treated) group. In addition, telomerase reverse transcriptase (TERT) mRNA expression levels were increased in endosulfan-treated mammary glands in a dose-dependent manner. Telomerase can be activated by estrogen, therefore, we examined the effects of endosulfan on telomerase activity, and found that the telomerase activity in estrogen receptor-positive MCF-7 cells was up-regulated by endosulfan treatment. Moreover, this activation was accompanied by the up­regulation of the TERT mRNA expression. Also, transient expression assays using CAT reporter plasm ids containing various fragments of the TERT promoter showed that this imperfect palindromic estrogen-responsive element is almost certainly responsible for the transcriptional activation by endosulfan. These results may help elucidate the endocrine disrupting mechanism of endosulfan.

• 생명과학회지
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• 제19권4호
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• pp.502-507
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• 2009

본 연구에서는 봉독의 처리에 따른 A549 폐암세포의 증식억제에서 $PGE_2$ 생성 및 telomerase 활성의 변화 관련성을 조사하였다. A549 세포의 증식은 봉독 처리에 의하여 유의적으로 감소되었으며, 이는 apoptosis 유발과 연관성이 있음을 알 수 있었다. 봉독 처리 농도의 증가에 따라 COX-2의 발현이 전사 및 번역 수준에서 모두 감소되었으며 이에 따른 $PGE_2$의 생성이 현저하게 감소되었으나, COX-1의 발현에는 큰 변화가 없었다. 또한 봉독 처리에 따라 telomere 조절인자들 중, hTERT, hTR 및 c-myc의 발현이 억제되었으며, telomerase의 활성도 매우 감소되었다. 본 연구의 결과는 $PGE_2$ 생성과 telomerase 활성 저하가 봉독의 항암 작용 표적인자로서 작용될 수 있음을 보여준다.

• 생명과학회지
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• 제18권6호
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• pp.884-890
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• 2008

본 연구에서는 대두의 대표적인 생리활성 물질인 genistein의 처리에 따른 암세포의 증식억제에서 telomerase 및 COX-2 활성의 변화 연관성을 조사하였다. 이를 위하여 4가지 종류의 암세포주를 사용하였으며, genistein 처리에 의하여 암세포들의 증식억제에서 백혈병 세포인 U937 세포의 감수성이 감장 높게 나타났으며, genistein 처리에 따라 telomere 조절인자들의 발현이 대부분 억제되었으며, telomerase의 활성도 매우 유의적으로 감소되었다. 또한 genistein처리 농도가 증가함에 따라 COX-2의 발현이 전사 및 번역 수준에서 모두 감소되었으며 이에 따른 $PGE_2$의 생성 역시 현저하게 감소되었으나, COX-1의 발현에는 큰 변화가 없었다. 이러한 결과들은 genistein의 항암 활성을 이해하는 귀중한 자료로서 활용될 것으로 생각된다.

• 동의생리병리학회지
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• 제19권1호
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• pp.167-173
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• 2005

To investigate the possible molecular mechanism (s) of bee venom as a candidate of anti-cancer drug, we examined the effects of the compound on the growth of human lung carcinoma cell line A549. Bee venom treatment declined the cell growth and viability of A549 cells in a concentration-dependent manner, which was associated with induction of apoptotic cell death. Bee venom down-regulated the levels of anti-apoptotic genes such as Bcl-2 and Bcl-XS/L, however, the levels of Bax, a pro-apoptotic gene, were up-regulated. Bee venom treatment induced not only tumor suppressor p53 but also cyclin-dependent kinase inhibitor p21WAF1/CIP1 expression in a dose-dependent manner. Furthermore, bee venom treatment induced the down-regulation of telomerase reverse transcriptase mRNA and telomeric repeat binding factor expression of A549 cells, however, the levels of telomerase-associated protein-1 and c-myc were not affected. Taken together, these findings suggest that bee venom-induced inhibition of human lung cancer cell growth is associated with the induction of apoptotic cell death via regulation of several major growth regulatory gene products, and bee venom may have therapeutic potential in human lung cancer.

• 생명과학회지
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• 제34권6호
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• pp.365-376
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• 2024

이 연구는 여러 종류의 암세포주(A-549, AGS, HCT-116, MDA-MB-231 및 U 87-MG)와 정상세포주(MRC-5 및 MSC)에 RNA를 DNA로 전환시킬 수 있는 역전사 효소의 억제 처리 후 세포의 성장에 미치는 영향을 비교 조사하였다. 각 세포주에 efavirenz (EFA) 역전사 효소 억제제를 1주일 동안 처리하였을 때, 세포 성장의 반억제농도(IC₅₀) 값은 암세포주보다 정상세포주에서 더 높은 값을 나타냈다. 결정된 IC₅₀ 값에 따라 15 µM 농도로 EFA를 1주일 동안 처리하였을 때, 역전사 효소 및 말단소립 복원 효소의 활성은 EFA 처리군에서 비처리군에 비하여 유의적으로(p<0.05) 감소하였다. 그러나, 역전사 효소 및 말단소립 복원효소의 활성은 정상세포주에서는 검출되지 않았다. 15 µM EFA를 처리한 후, 암세포주와 정상세포주에서 세포성장율을 비교하였을 때, EFA 처리는 모든 세포의 성장을 억제하였는데, 정상세포주보다 암세포주에서 세포의 성장율이 현저하게(p<0.05) 감소하였다. 또한, 역전사 효소의 억제가 세포의 노화 및 사멸에 미치는 영향을 분석하기 위해 노화 관련 ß-galactosidase 효소의 활성을 분석하였을 때, EFA 처리가 노화관련 효소 활성이 점점 증가하는 것으로 보아, EFA 역전사 효소의 처리는 세포 노화 및 세포 사멸을 유도하는 것을 알 수 있었다. 이상의 결과를 바탕으로, 역전사 효소의 억제는 정상세포보다는 암세포의 성장을 더 억제하는 것을 알 수 있었지만, 항암치료 등에서 응용되기 위해서는 세포에서 역전사 효소의 기능과 역할에 대해서는 좀 더 심도있는 연구가 필요할 것으로 생각된다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6363-6367
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• 2013

Atractylis lancea (Thunb.) DC. (AL), an important medicinal herb in Asia, has been shown to have anti-tumor effects on cancer cells, but the involved mechanisms are poorly understood. This study focused on potential effects and molecular mechanisms of AL on the proliferation of the Hep-G2 liver cancer cell line in vitro. Cell viability was assessed by MTT test in Hep-G2 cells incubated with an ethanol extract of AL. Then, the effects of AL on apoptosis and cell cycle progression were determined by flow cytometry. Telomeric repeat amplification protocol (TRAP) assays was performed to investigate telomerase activity. The mRNA and protein expression of human telomerase reverse transcriptase (hTERT) and c-myc were determined by real-time RT-PCR and Western blotting. Our results show that AL effectively inhibits proliferation in Hep-G2 cells in a concentrationand time-dependent manner. When Hep-G2 cells were treated with AL after 48h,the $IC_{50}$ was about 72.1 ${\mu}g/mL$. Apoptosis was induced by AL via arresting the cells in the G1 phase. Furthermore, AL effectively reduced telomerase activity through inhibition of mRNA and protein expression of hTERT and c-myc. Hence, these data demonstrate that AL exerts anti-proliferative effects in Hep-G2 cells via down-regulation of the c-myc/hTERT/telomerase pathway.

• 동의생리병리학회지
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• 제18권2호
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• pp.500-506
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• 2004

The objective of the present study was to investigate the effects of aqueous extract from the healthful decoction utilizing Phellinus linteus (HDPL) on the growth of human lung carcinoma A549 cells. HDPL treatment declined the cell viability of A549 cells in a concentration-dependent manner and the anti-proliferative effects by HDPL treatment were associated with morphological changes such as membrane shrinking and cell rounding up. HDPL treatment did not affect the distribution of the cell cycle. Western blot analysis and RT-PCT data revealed that the levels of tumor suppressor p53 and cyclin-dependent kinase inhibitor p21WAF1/CIP1 in HDPL-treated A549 cells were remained unchanged. However, HDPL treatment inhibited the expression of cyclooxygenase-2 (COX-2) mRNA and protein in a concentration-dependent fashion. Additionally, the expression of human telomerase reverse transcriptase (hTERT), a main determinant of the telomerase enzymatic activity, was progressively down-regulated by HDPL treatment. Taken together, these findings suggest that HDPL-induced inhibition of human lung cancer cell proliferation is associated with the inhibition of several major growth regulatory gene products, such as COX-2 and hTERT, and HDPL may have therapeutic potential in human lung cancer.