• Journal of Life Science
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• v.25 no.11
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• pp.1331-1337
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• 2015

S-allylcysteine (SAC) is an aged garlic derived water soluble organosulfur compound and has been suggested to have anticarcinogenic activity against diverse types of cancer cells. This review summarizes the cellular signaling pathways and molecular mechanisms whereby SAC exerts its effects on cellular proliferation, apoptosis, cell cycle progression and metastasis based on the results from both in vitro and in vivo studies. SAC activates proapoptotic proteins including Bax and caspase-3, but suppresses antiapoptotic Bcl-2 family proteins to bring about cancer cell death through mitochondria-mediated intrinsic pathway. SAC also inhibits cellular proliferation by inducing cell cycle arrest in which SAC reduces expression and activation of NF-κB, cyclins, Cdks, PCNA and c-Jun, but elevates expression of cell cycle inhibitor proteins p16 and p21 through suppression of both PI3K/Akt/mTOR and MAPK/ERK signaling pathways. And, SAC inhibits invasion and metastasis of cancer cells by inducing suppression of both angiogenesis and epithelial-mesenchymal transition (EMT) through decreased cyclooxygenase (COX)-2 expression and increased E-cadherin expression which were then caused by suppression of inhibitory transcription factors Id-1 and SLUG from SAC-mediated inactivation of both MAPK/ERK and PI3K/Akt/mTOR/NF-κB signaling pathways. Furthermore, SAC prevents toxic compound-induced carcinogenesis by inducing antioxidant enzymes such as glutathione-s-transferase (GST). Thus, SAC can be considered as a potential chemotherapeutic agent for the prevention and treatment of cancer.

• BMB Reports
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• v.51 no.12
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• pp.630-635
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• 2018

C-X-C motif chemokine ligand 2 (CXCL2) is a small secreted protein that exhibits a structure similar to the proangiogenic subgroup of the CXC chemokine family. Recently, accumulating evidence suggests that chemokines play a pivotal role in cancer progression and carcinogenesis. We examined the expression levels of 7 types of $ELR^+$ CXCLs messenger RNA (mRNA) in 264 clinical samples. We found that CXCL2 expression was stably down-regulated in 94% of hepatocellular carcinoma (HCC) specimens compared with paired adjacent normal liver tissues and some HCC cell lines. Moreover, CXCL2 overexpression profoundly attenuated HCC cell proliferation and growth and induced apoptosis in vitro. In animal studies, we found that overexpressing CXCL2 by lentivirus also apparently inhibited the size and weight of subcutaneous tumours in nude mice. Furthermore, we demonstrated that CXCL2 induced HCC cell apoptosis via both nuclear and mitochondrial apoptosis pathways. Our results indicate that CXCL2 negatively regulates the cell cycle in HCC cells via the ERK1/2 signalling pathway. These results provide new insights into HCC and may ultimately lead to the discovery of innovative therapeutic approaches of HCC.

• Molecules and Cells
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• v.27 no.4
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• pp.443-447
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• 2009

This paper reports on the structural rearrangement of satellite DNA type I repeats and heterochromatin during the dedifferentiation and cell cycling of mesophyll protoplasts of cucumber (Cucumis sativus). These repeats were localized in the telomeric heterochromatin of cucumber chromosomes and in the chromocenters of interphase nuclei. The dramatic reduction of heterochromatin involves decondensation of subtelomeric repeats in freshly isolated protoplasts; however, there are not a great many remarkable changes in the expression profile. In spite of that, reformation of the chromocenters, occurring 48 h after protoplast isolation, is accompanied by recondensation of satellite DNA type I; however, only partial reassembly of these repeats was revealed. In this study, FISH and a flow cytometry assay show a correlation between the partial chromocenter and the repeats reassembly, and with the reentry of cultivated protoplasts into the cell cycle and first cell division. After that, divided cells displayed a higher variability in the expression profile than did leaves' mesophyll cells and protoplasts.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.1
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• pp.55-60
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• 2010

Caesalpinia sappan L. (C. sappan) has long been used in traditional medicine as an emmenagogue, hemostatic and anti-inflammatory agent. The present study investigated the effects of water extract of C. sappan in human lymphoma U937 cells. The proliferation of U937 cells was decreased by C. sappan in a dose-dependently manner. Anti-proliferative effect of C. sappan on U937 cells was associated with G2/M phase arrest, which was mediated by regulating the expression of p21 protein. Moreover, phosphorylation of JNK and p38 was increased by C. sappan. Blockade of JNK and p38 was significantly inhibited C. sappan-induced G2/M phase arrest. Taken together, these results suggest that Anti-proliferative effect of C. sappan on U937 is assocated with G2/M phase cell cycle arrest by expression of p21 protein and, JNK and p38 activation.

• BMB Reports
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• v.31 no.4
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• pp.333-338
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• 1998

The sphingomyelin cycle and ceramide generation have been recognized as potential growth suppression signals in mammalian cells. Ceramide has been shown to induce differentiation, cell growth arrest, senescence, and apoptosis. Although the intracelluar target for the action of ceramide remains unknown, recent studies have demonstrated the role of cytosolic ceramideactivated protein phosphatase(CAPP). In this study, the cytotoxic effect of C2-ceramide, a synthetic cellpermeable ceramide analog, on HEp-2 cells and the mechanism by which ceramide induces cell death were investigated. The addition of exogenous C2-ceramide resulted in a concentration dependent cell death. Okadaic acid, a potent inhibitor of CAPP, enhanced ceramide-mediated cell death, which suggests that CAPP is not involved in this process. To understand the mechanism of action of ceramide, we studied the relationship between ceramide and c-Myc and pRb which are defined components of cell growth regulation. Western blot analyses revealed that C2-ceramide (10${\mu}M$) induced c-Myc down-regulation, but there were no significant changes in pRb. However, treatment of okadaic acid (10 nM) enhanced c-Myc and pRb down-regulation. Reduction of the amount of c-Myc and pRb occurred during HEp-2 cell death. These results suggest that the cytotoxic effect of ceramide in HEp-2 cells may not be mediated through the action of CAPP and that the downstream target for ceramide is c-Myc and pRb.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2525-2528
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• 2013

The Homer protein family, also known as the family of cytoplasmic scaffolding proteins, which include three subtypes (Homer1, Homer2, Homer3). Homer3 can regulate transcription and play a very important role in the differentiation and development for some tissues (e.g. muscle and nervous systems). The current studies showed that Homer3 abnormal expression changes in acute myeloid leukemia (AML). Forced expression of Homer3 in transfected K562 cells inhibited proliferation, influenced the cell cycle profile, affected apoptosis induced by $As_2O_3$ through inhibition of Bcl2 expression, and also promoted cell differentiation induced by 12-O-tetra decanoylphorbol-acetate (TPA). These results showed that Homer3 is a novel gene which plays a certain role in the occurrence and development of AML.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1640-1647
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• 2015

We recently reported that the antimicrobial peptide Lumbricusin (NH₂-RNRRWCIDQQA), isolated from the earthworm, increases cell proliferation in neuroblastoma SH-SY5Y cells. Here, we investigated whether Lumbricusin has neurotropic activity in mouse neural stem cells (MNSCs) and a protective effect in a mouse model of Parkinson's disease (PD). In MNSCs isolated from mouse brains, Lumbricusin treatment significantly increased cell proliferation (up to 12%) and reduced the protein expression of p27^Kip1 through proteasomal protein degradation but not transcriptional regulation. Lumbricusin inhibited the 6-OHDA-induced apoptosis of MNSCs, and also showed neuroprotective effects in a mouse PD model, ameliorating the motor impairments seen in the pole, elevated body swing, and rotation tests. These results suggest that the Lumbricusin-induced promotion of neural cell proliferation via p27^Kip1 degradation has a protective effect in an experimental PD model. Thus, the antimicrobial peptide Lumbricusin could possibly be developed as a potential therapeutic agent for the treatment of PD.

• The Journal of Korean Society of Virology
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• v.30 no.3
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• pp.161-170
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• 2000

Continuous efforts are being made to find effective therapeutic agents against HIV-1, the causative agents of AIDS. In this study, we developed a cell-based assay system employing a trans-complementation for production of recombinant viruses which are capable of undergoing one round of replication in CD4+ T cells. This assay system was tested for ability to screen the agents that act at late stage of HIV-1 life cycle. The effect of a protease inhibitor on the trans-complementation assay was assessed. Recombinant HIV-1 viruses were prepared from a trans-complementation in the presence of various concentrations of protease inhibitor. Inhibition of single round infection of these recombinant viruses by protease inhibitor was observed to be a dose-dependent manner. Inhibitory effects of a protease inhibitor on HIV-1 Gag polyprotein processing by HIV-1 protease was detected at concentrations of the protease inhibitor compatible with inhibition of virus infection, confirming that the corresponding step was involved in the inhibitory mechanism of this compound. Together, these results provide evidence that a cell-based assay system established in this study can be used to screen the agents that target the late stage of HIV-1 life cycle.

• BMB Reports
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• v.51 no.11
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• pp.547-548
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• 2018

Phloem network integrates cellular energy status into post-embryonic growth, and development by tight regulation of carbon allocation. Phloem development involves complicated coordination of cell fate determination, cell division, and terminal differentiation into sieve elements (SEs), functional conduit. All of these processes must be tightly coordinated, for optimization of systemic connection between source supplies and sink demands throughout plant life cycle, that has substantial impact on crop productivity. Despite its pivotal role, surprisingly, regulatory mechanisms underlying phloem development have just begun to be explored, and we recently identified a novel translational regulatory network involving RNA G-quadruplex and a zinc-finger protein, JULGI, for phloem development. From this perspective, we further discuss the role of RNA G-quadruplex on post-transcriptional control of phloem regulators, as a potential interface integrating spatial information for asymmetric cell division, and phloem development.

• Proceedings of the Korean Society of Life Science Conference
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• 2005.04a
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• pp.229-229
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• 2005