• Molecules and Cells
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• 제37권8호
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• pp.620-627
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• 2014

We have previously shown that microRNAs (miRNAs) miR-760, miR-186, miR-337-3p, and miR-216b stimulate premature senescence through protein kinase CK2 (CK2) downregulation in human colon cancer cells. Here, we examined whether these four miRNAs are involved in the replicative senescence of human lung fibroblast IMR-90 cells. miR-760 and miR-186 were significantly upregulated in replicatively senescent IMR-90 cells, and their joint action with both miR-337-3p and miR-216b was necessary for efficient downregulation of the ${\alpha}$ subunit of CK2 ($CK2{\alpha}$) in IMR-90 cells. A mutation in any of the four miRNA-binding sequences within the $CK2{\alpha}3^{\prime}$-untranslated region (UTR) indicated that all four miRNAs should simultaneously bind to the target sites for $CK2{\alpha}$ downregulation. The four miRNAs increased senescence-associated ${\beta}$-galactosidase (SA-${\beta}$-gal) staining, p53 and $p21^{Cip1/WAF1}$ expression, and reactive oxygen species (ROS) production in proliferating IMR-90 cells. $CK2{\alpha}$ overexpression almost abolished this event. Taken together, the present results suggest that the upregulation of miR-760 and miR-186 is associated with replicative senescence in human lung fibroblast cells, and their cooperative action with miR-337-3p and miR-216b may induce replicative senescence through $CK2{\alpha}$ downregulation-dependent ROS generation.

• 대한의생명과학회지
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• 제20권2호
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• pp.85-95
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• 2014

Activation of the epidermal growth factor receptor (EGFR) and downstream signaling pathways have been implicated in causing resistance to EGFR-targeted therapy in solid tumors, including the head and neck tumors. To investigate the mechanism of antiproliferation to EGFR inhibition in oral cancer, we compared EGFR tyrosine kinase inhibitor (Gefitinib, Iressa, ZD1839) with respect to its inhibitory effects on three kinases situated downstream of EGFR: MAPK, Akt, and glycogen synthase kinase-$3{\beta}$ (GSK-$3{\beta}$). We have demonstrated that ZD1839 induces growth arrest and apotosis in oral cancer cell lines by independent of EGFR-mediated signaling. An exposure of oral cancer cells to ZD1839 resulted in a dose dependent up-regulation of the cyclin-dependent kinase inhibitor p21 and p27, down regulation of cyclin D1, inactivation of GSK-$3{\beta}$ and of active MAPK. In resistant cells, GSK-$3{\beta}$ is constitutively active and its activity is negatively regulated primarily through Ser 9 phosphorylation and further enhanced by Tyr216 phosphorylation. These results showed that the resistance to the antiproliferative effects of ZD1839, in vitro was associated with uncoupling between EGFR and MAPK inhibition, and that GSK-$3{\beta}$ activation and degradation of its target cyclin D1 were indicators of high cell sensitivity to ZD1839. In conclusion, our data show that the uncoupling of EGFR with mitogenic pathways can cause resistance to EGFR inhibition in oral cancer.

• 생명과학회지
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• 제15권2호
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• pp.169-175
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• 2005

Resveratrol (3,4',5-trihydroxy-trans-stilbene)은 포도와 같은 식물에서 각종 감염균으로부터 자신의 몸을 보호하기 위하여 생성되는 물질인 phytoalexin의 일종으로 강력한 항산화작용, 암예방 효과 및 항암 작용을 포함한 각종 약리작용을 가진 것으로 보고 되어져 오고 있다. Alzheimer 환자의 뇌에 축적되어 뇌 신경세포를 죽이는 amyloid plaque의 주 성분은 $amyloid-\beta$의 축적에 의한 것인데, $amyloid-\beta$는 정상적인 단백질 신진대사 과정의 결과로 체내 모든 세포들로부터 생성되는 물질이다. 본 연구에서는 resveratrol의 세포독성 보호효과에 관한 효능을 검증하기 위하여 C6 신경교세포에서 $amyloid-\beta-peptide$ (fragment 31-35)에 의한 세포독성 및 세포성장 조절관련 주요 유전자들의 발현에 미치는 resveratrol의 영향을 조사하였다. $Amyloid-\beta$가 처리된 C6세포는 처리 농도의존적으로 증식이 억제되었으며, 형태적 변형도 유발 되었으나 resveratrol의 전처리에 의하여 효과적으로 차단되었다. RT-PCR 및 Western blot analysis에 의한 결과에서 $amyloid-\beta$ 처리에 의한 세포증식 억제는 종양억제유전자 p53 및 Cdk 억제제인 p21 (WAF1/CIP1) 발현이 증가되었다. 또한 apoptosis 유발에 매우 중요한 역할을 수행하는 Bax의 발현도 $amyloid-\beta$가 처리된 C6 세포에서 발현이 증가되었으나 apoptosis 유발억제에 관여하는 Bcl-2및 $Bcl-X_{L}$ 발현에는 큰 영향을 미치지 못하였다. 그러나 resveratrol이 전처리된 세포에서는 처리 농도 의존적으로 $amyloid-\beta$에 의해 유도되는 p53, p21 및 Bax의 발현이 정상수준으로 회복되었다.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1998년도 Advances in Ginseng Research - Proceedings of the 7th International Symposium on Ginseng -
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• pp.231-243
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• 1998

In the present study, we provide evidence that ginsenoside $Rh_2$ (G-$Rh_2$) as well as staurosporine induces apoptosis of human hepatoma SK-HEP-1 cells by caspase 3-mediated processing of $p21^{WAFI/CIPI}$ in the early stage of apoptosls. Immunoblottings showed that G-$Rh_2$ as well as statrosporine induced the processing of caspase-3 to an active form, pl7. In stable Bcl-2 transfectants however, G-$Rh_2$ induced DNA fragmentation, while staurosporine did not. In the early stage of apoptosis, $p21^{WAFI/CIPI}$ was detected to undergo proteolytic processing specifically conducted by caspase-3. $p21^{WAFI/CIPI}$ translated in vitro was cleaved into a p14 fragment, when incubated with cell extracts obtained from either G-$Rh_2$- or staurosporine-treated cells. Cleavage was equally inhibited in both cases by adding Ac-DEVD-cho, a specific caspase-3 inhibitor, but not by Ac-YVkD-cho, a specific caspase-l inhibitor. Similarly, $p21^{WAFI/CIPI}$ was efficiently leaved by recombinant caspase-3 overexpressed in E. coli. Moreover, the endogenous $p21^{WAFI/CIPI}$ of untreated-cell extracts was also cleaved by recombinant caspase-3. Mutation analysis allowed identification of two caspase-3 cleavage sites, $DHVD^{112}$/L and $SMTD^{149}$/F, which are located within, or near the interaction domains for cyclins, Cdks, and PCNA. Taken together, these results show that G-$Rh_2$ as well as staurosporine increases caspase-3 activity, which in turn directly cleaves $p21^{WAFI/CIPI}$ resulting in elevation of Cdk kinase activity in the early stages of apoptosis. We propose that proteolytic cleavage of $p21^{WAFI/CIPI}$ is a functionally relevant event that allows unleashing the cyclin/Cdk activity from the inhibitor seen in the earlier stage of apoptosis, the event of which may be associated with the triggering mechanism for the execution of apoptosis.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.150.1-150.1
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• 2003

Gelsolin, a actin binding protein, has been demonstrated to be involved in controlling cell morphology, motility, signaling, and apoptosis. It's expression is frequently downregulated in cervix cancer and several types of different human cancers indicating the role of gesolin in suppression of tumorigenicity. Apicidin, a novel histone deacetylase inhibitor, has been shown to cause growth arrest and morphological change of cancer cells, resulting from the alternation of protein expression, such as p21^${WAF1/Cip1}$ and gelsolin. (omitted)

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.323.1-323.1
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• 2002

Apicidin ［cyclo(N-O-methyl-l -tryptophanyl-L -isoleucinyl-D-pipecolinyl-L-2-amino-8-oxodecano y)］. a histone deacetylase inhibitor. has been shown to cause growth arrest and morphological change of cancer cells. resulting from the alternation of protein expression. such as p21WAF1/Cip1 and gelsolin. However. proteome of altered by apicidin are poorly studied. In this study. we used a functional proteornics approach to identify the proteome altered by apicidin in Hela cells at 24hr post-treatment. (omitted)

• Archives of Pharmacal Research
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• 제26권12호
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• pp.1055-1060
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• 2003

Lysophosphatidic acid (LPA) is a well-known mitogen in various cell types. However, we found that LPA inhibits melanocyte proliferation. Thus, we further investigated the possible signaling pathways involved in melanocyte growth inhibition. We first examined the regulation of the three major subfamilies of mitogen-activated protein (MAP) kinases and of the Akt pathway by LPA. The activations of extracellular signal-regulated protein kinase (ERK) and c-Jun N-terminal kinase (JNK) were observed in concert with the inhibition of melanocyte proliferation by LPA, whereas p38 MAP kinase and Akt were not influenced by LPA. However, the specific inhibition of the ERK or JNK pathways by PD98059 or D-JNKI1, respectively, did not restore the antiproliferative effect. We next examined changes in the expression of cell cycle related proteins. LPA decreased cyclin $D_1 and cyclin D_2$ levels but increased $p21^{WAF1/CIP1}$ (p21) and $p27^{KIP1}$ (p27) levels, which are known inhibitors of cyclin-dependent kinase. Flow cytometric analysis showed the inhibition of DNA synthesis by a reduction in the S phase and an increase in the $G_0/G_1$ phase of the cell cycle. Our results suggest that LPA induces cell cycle arrest by regulating the expressions of cell cycle related proteins.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2001년도 제31회 학술심포지움 및 춘계학술대회
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• pp.77-77
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• 2001

• International Journal of Oral Biology
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• 제41권3호
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• pp.113-118
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• 2016

An FDA approved drug for the treatment of type II diabetes, Troglitazone (TRO), a peroxisome proliferator-activated receptor gamma agonist, is withdrawn due to severe idiosyncratic hepatotoxicity. In the search for new applications of TRO, we investigated the cellular effects of TRO on YD15 tongue carcinoma cells. TRO suppressed the growth of YD15 cells in the MTT assay. The inhibition of cell growth was accompanied by the induction of cell cycle arrest at $G_0/G_1$ and apoptosis, which are confirmed by flow cytometry and western blotting. TRO also suppressed the expression of cell cycle proteins such as cyclin D1, cdk2, cdk4, cyclin B1, cdk1(or cdc2), cyclin E1 and cyclin A. The inhibition of cell cycle proteins was coincident with the up-regulation of $p21^{CIP1/WAF1}$ and $p27^{KIP1}$. In addition, TRO induces the activation of caspase-3 and caspase-7, as well as the cleavage of PARP. Further, TRO suppressed the expressions of Bcl-2 without affecting the expressions of Bad and Bax. Overall, our data supports that TRO induces cell cycle arrest and apoptosis on YD15 cells.

• 대한한의학방제학회지
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• 제21권2호
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• pp.53-62
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• 2013

Objectives : Diabetic nephropathy is associated with morbidity and mortality of diabetes mellitus patients. Mesangial cell proliferation is known as the major pathologic features such as glomerulosclerosis. Oryeong-san, Korean formula, is widely used for the treatment of nephrosis, edema, and uremia. Oryeong-san is composed of five herbs: Alismatis Rhizoma, Polyporus, Atractylodis Rhizoma Alba, Hoelen, and Cinnamomi Cortex. Methods : The present study was performed to investigate potent inhibitory effect of Oryeong-san on high glucose (HG)-induced rat mesangial cells (RMC) proliferation. Results : RMC proliferation under 25 mM glucose was significantly accelerated compared with 5.5 mM glucose, which was inhibited by Oryeong-san in dose dependent manner. Pre-treatment of Oryeong-san induced down-regulation of cyclins/CDKs and up-regulation of CDK inhibitor, p21waf1/cip1 and p27kip1 expression. In addition, Oryeong-san reduced HG-induced RMC proliferation by suppressed the mitogen-activated protein kinase (MAPK) phospholyration such as extracellular signal regulated kinase (ERK), Jun N-terminal Kinase (JNK), and p38. Oryeong-san significantly suppressed HG-induced ROS production. Conclusions : Oryeong-san consequently inhibited HG-induced mesangial cell proliferation through the inhibition of MAPK and ROS signaling pathway. These results suggest that Oryeong-san may be effective in the treatment of renal dysfunction leading to diabetic nephropathy.