• Korean Journal of Plant Resources
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• v.31 no.3
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• pp.218-227
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• 2018

In this study, we investigated the effect of the extracts from Vaccinium oldhamii on cell proliferation and the regulatory mechanisms of cyclin D1 protein level in human cancer cells. The branch extracts from Vaccinium oldhamii (VOB) showed higher inhibitor effect against the cell growth than leave extracts (VOL) and fruit extracts (VOF) in human colorectal cancer, breast cancer, prostate cancer, non-small lung cancer, pancreatic cancer and liver cancer cells. In addition, VOB decreased cyclin D1 level at both protein and mRNA level. MG132 treatment attenuated VOB-mediated cyclin D1 downregulation. A point mutation of threonine-286 to alanine attenuated cyclin D1 degradation by VOB. In addition, the inhibition of nuclear export by leptomycin B (LMB) attenuated cyclin D1 degradation by VOB. But, the treatment of PD98059 (ERK1/2 inhibitor), SB203580 (p38 inhibitor), SP600125 (JNK inhibitor), LiCl ($GSK3{\beta}$ inhibitor), LY294002 (PI3K inhibitor) or BAY 11-7082 ($I{\kappa}K$ inhibitor) did not affect VOB-induced cyclin D1 degradation. In conclusion, VOB induced cyclin D1 degradation through redistribution of cyclin D1 from the nucleus to cytoplasm via T286 phosphorylation of cyclin D1, which resulted in the inhibition of cancer cell proliferation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.62-67
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• 2019

We studied the effect of several sex-related steroid hormones (serotonin, progesterone and ${\beta}$-estradiol) for 6 days on the induction of sexual reproduction for the mass production of resting eggs in the marine rotifer Brachionus rotundiformis. The highest mix rate of 20.6% appeared with the ${\beta}$-estradiol ($E_2$) treatment on the third day. The number of resting eggs was highest with $E_2$ treatment, followed by that of the serotonin treatment group. In addition, we investigated the effect of the hormones on the expression pattern of the genes related to sexual reproduction in the rotifer. NrbP, SRY, Cyclin and MrpmB genes were up-regulated with all the hormone treatments. As a result, ${\beta}$-estradiol was more effective than the other hormone treatments to produce resting eggs in B. rotundiformis. We suggest that the sexual reproduction-related genes in the rotifer are the NrbP, SRY, Cyclin and MrpmB genes. Further study is required to determine the optimum concentration of $E_2$ for the effective production of resting eggs in the rotifer.

• Journal of Life Science
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• v.25 no.10
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• pp.1184-1195
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• 2015

The zebrafish is an emerging vertebrate model organism in reproductive biology. The oocyte maturation of zebrafish is triggered by maturation inducing hormone (MIH, 17α,20β-Dihydroxy-4-pregnen-3-one). In almost all animals, the oocyte maturation is governed by activation of pre-MPF which consists of cyclinB and inactive Cdk1. In the oocyte of Xenopus and mice, the activity of Cdk1 is regulated in two ways, one is the interaction with cyclinB and the other is phosphorylation/dephosphorylation of T14/Y15 residues on the Cdk1 by Wee1 and Cdc25. Unlike Xenopus and mice that have a sufficient amount of pre-MPF, pre-MPF is absent in GV oocyte of most teleost including zebrafish. Therefore, the activation of MPF during zebrafish oocyte maturation might totally depend on de novo synthesis of cyclinB proteins. It is reported that the translation of maternal mRNA is regulated by combination of several RNA binding proteins such as CPEB, Dazl, Pum1/Pum2, and insulin-like growth factor2 mRNA-binding protein 3 in the zebrafish oocytes. However, the definitive mechanism of these proteins to regulate the translation of stored maternal mRNAs remains to be elucidated. Therefore, the investigation of the maturation process of the zebrafish oocyte will provide new information that can help identify the role of translational control in early vertebrate oocyte maturation.

• Journal of Life Science
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• v.16 no.4
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• pp.589-597
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• 2006

Genistein, a natural isoflavonoid phytoestrogen, is a strong inhibitor of protein tyrosine kinase and DNA topoisomerase activities. There are several studies documenting molecular alterations leading to cell cycle arrest and induction of apoptosis by genistein as a chemopreventive agent in a variety of cancer cell lines; however, its mechanism of action and its molecular targets on human bladder carcinoma and leukemic cells remain unclear. In the present study, we have addressed the mechanism of action by which genistein suppressed the proliferation of T24 bladder carcinoma and U937 leukemic cells. Genistein significantly inhibited the cell growth and induced morphological changes, and induced the G2/M arrest of the cell cycle in both T24 and U937 cells with a relatively stronger cytotoxicity in U937. The G2/M arrest in T24 cells was associated with the inhibition of cyclin A, cyclin B1 and Cdc25C protein expression without alteration of tumor suppressor p53 and cyclin-dependent kinase (Cdk) inhibitor p21(WAF1/CIP1). However, the inhibitory effects of genistein on the cell growth of U937 cells were connected with a marked inhibition of cyclin B1 and an induction of Cdk inhibitor p21 proteins by p53-independent manner. These data suggest that genistein may exert a strong anticancer effect and additional studies will be needed to evaluate the different mechanisms between T24 and U937 cells.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.9
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• pp.4101-4107
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• 2014

Protein phosphatase 1 (PP1) is a major serine/threonine phosphatase that controls gene expression and cell cycle progression. The active mutant IPP5 ($8-60hIPP5^m$), the latest member of the inhibitory molecules for PP1, has been shown to inhibit the growth of human cervix carcinoma cells (HeLa). In order to elucidate the underlying mechanisms, the present study assessed overexpression of $8-60hIPP5^m$ in HeLa cells. Flow cytometric and biochemical analyses showed that overexpression of $8-60hIPP5^m$ induced G2/M-phase arrest, which was accompanied by the upregulation of cyclin B1 and phosphorylation of G2/M-phase proteins ATM, p53, $p21^{cip1/waf1}$ and Cdc2, suggesting that $8-60hIPP5^m$ induces G2/M arrest through activation of the ATM/p53/$p21^{cip1/waf1}$/Cdc2/cyclin B1 pathways. We further showed that overexpression of $8-60hIPP5^m$ led to delayed nuclear translocation of cyclin B1. $8-60hIPP5^m$ also could translocate to the nucleus in G2/M phase and interact with $pp1{\alpha}$ and Cdc2 as demonstrated by co-precipitation assay. Taken together, our data demonstrate a novel role for $8-60hIPP5^m$ in regulation of cell cycle in HeLa cells, possibly contributing to the development of new therapeutic strategies for cervix carcinoma.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6437-6441
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• 2014

Background: Oridonin isolated from Rabdosia rubescens, a plant used to treat cancer in Chinese folk medicine, is one of the most important antitumor active ingredients. Previous studies have shown that oridonin has antitumor activities in vivo and in vitro, but little is known about cell cycle effects of oridonin in gastric cancer. Materials and Methods: MTT assay was adopted to detect the proliferation inhibition of SGC-7901 cells, the cell cycle was assessed by flow cytometry and protein expression by Western blotting. Results: Oridonin could inhibit SGC-7901 cell proliferation, the $IC_{50}$ being $15.6{\mu}M$, and blocked SGC-7901 cell cycling in the $G_2/M$ phase. The agent also decreased the protein expression of cyclinB1 and CDK1. Conclusions: Oridonin may inhibit SGC-7901 growth and block the cells in the $G_2/M$ phase by decreasing Cdk1 and cyclinB1 proteins.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.02a
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• pp.21-23
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• 2003

Mechanisms regulate the arrest and growth of the resting primordial follicles are very poorly understood. To elucidate genes involved in the early folliculogenesis, we conducted suppression subtractive hybridization using mRNA from day1 and day5 ovaries and selected weel for further analysis, since it was most frequent gene in the day1-subtracted cDNA library (1). Expression of weel and correlated components of the cell cycle machinery, such as cdc2, cyclin B1, cdc25C, and phosphorylated cdc2 was evaluated by immunohistochemistry. In primordial follicles, expression of weel, cdcw, and cyclin B1 was cytoplasmic in oocytes, but phosphorylated cdc2 was weakly expressed in oocytes. While cdc25C expression was in ovarian somatic and in some theca cells. None of components was expressed in the pre-granulosa cells of the primordial follicles, while weel weakly, and cdc2 and cyclin B1 was strongly expressed in the granulosa cells of the growing follicles. Results from the present study suggest that 1) the mejotic arrest of the oocytes may not due to of cell cycle machinery, and 2) the weel may arrest meiosis by sequestering cdc2 and cyclin B1 in the cytoplasm by protein-protein interactions and/or by inhibitory phosphorylation.

• Journal of Life Science
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• v.11 no.4
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• pp.362-370
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• 2001

Regulation of cell proliferation is a complex process involving the regulated expression and /or modification of discrete gene products. which control transition between different stages of the cycle. The purpose of this short review is to provide an overview of somatic cell cycle events and their controls. Cycline have appeared as major positive regulators in this network, because their association to the cyclin-dependent kinases(Cdks) allows the subsequent activation on the Cdk/cyclin complexes and their catalatic activity. In mammalian cells, early to mid G1 progression and late G1 progression leading to S phase entry are directed by D-type cyclins-Cdk4, 6 and cyclin E-Cdk 2 both of which can phosphorylate the retinoblastoma protein (pRB). pRB is a transcriptional repressor which, in its unphosphorylated state, binds to members of the E2F transcription factor family and blocks E2F-dependent transcription of genes controlling the G1 to S phase transition an subsequent DNA synthesis. Cyclin A is produced in late G1 and expressed during S and G2 phae, and expression of B-type cyclins is typically maximal during the G2 to M phase transition and it controls the passage through M phase. They primarily associate with the activate Cdk2, and Cdc2, respectively. On the other hand, the Cdk inhibitors negatively control the activity of C아/cyclin complex by coordinating internal and/or external signals and impending proliferation at several key checkpoints. These current and further findings will provide novel approaches to understanding and treating major diseases.

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

• BMB Reports
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• v.56 no.10
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• pp.557-562
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• 2023

Dysregulation of the E3 ubiquitin ligase Parkin has been linked to various human cancers, indicating that Parkin is a tumor suppressor protein. However, the mechanisms of action of Parkin remain unclear to date. Thus, we aimed to elucidate the mechanisms of action of Parkin as a tumor suppressor in human lung and colorectal cancer cells. Results showed that Parkin overexpression reduced the viability of A549 human lung cancer cells by inducing G2/M cell cycle arrest. In addition, Parkin caused DNA damage and ATM (Ataxia telangiectasia mutated) activation, which subsequently led to p53 activation. It also induced the p53-mediated upregulation of p21 and downregulation of cyclin B1. Moreover, Parkin suppressed the proliferation of HCT-15 human colorectal cancer cells by a mechanism similar to that in A549 lung cancer cells. Taken together, our results suggest that the tumor-suppressive effects of Parkin on lung and colorectal cancer cells are mediated by DNA damage/p53 activation/cyclin B1 reduction/cell cycle arrest.