• Development and Reproduction
• /
• v.20 no.2
• /
• pp.141-147
• /
• 2016

Rad51 is a key component of homologous recombination (HR) to repair DNA double-strand breaks and it forms Rad51 recombinase filaments of broken single-stranded DNA to promote HR. In addition to its role in DNA repair and cell cycle progression, Rad51 contributes to the reprogramming process during the generation of induced pluripotent stem cells. In light of this, we performed reprogramming experiments to examine the effect of co-expression of Rad51 and four reprogramming factors, Oct4, Sox2, Klf4, and c-Myc, on the reprogramming efficiency. Co-expression of Rad51 significantly increased the numbers of alkaline phosphatase-positive colonies and embryonic stem cell-like colonies during the process of reprogramming. Co-expression ofRad51 significantly increased the expression of epithelial markers at an early stage of reprogramming compared with control cells. Phosphorylated histone H2AX (${\gamma}H2AX$), which initiates the DNA double-strand break repair system, was highly accumulated in reprogramming intermediates upon co-expression of Rad51. This study identified a novel role of Rad51 in enhancing the reprogramming efficiency, possibly by facilitating mesenchymal-to-epithelial transition and by regulating a DNA damage repair pathway during the early phase of the reprogramming process.

• Journal of Acupuncture Research
• /
• v.20 no.5
• /
• pp.93-106
• /
• 2003

Objective : To investigate the possible molecular mechanism(s) of melittin as a candidate of anti-cancer drug, we examined the effects of the compound on the growth of human lung carcinoma cell line A549. Methods: MTT, morphological changes, DAPI staining, Western blot, RT-PCR and in vitro prostaglandin E2 (PGE2) accumulation assays were performed. Results: The anti-proliferative effect by melittin treatment in A549 cells was associated with morphological changes such as membrane shrinking and cell rounding up. Melittin induced apoptotic cell death in a concentration-dependent manner, which was associated with inhibition or degradation of apoptotic target proteins such as ${\beta}$-catenin, poly(ADP-ribose) polymerase(PARP) and phospholipase $C-{\gamma}1(PLC-{\gamma}1)$. Melittin treatment inhibited the expression of cyclooxygenase-2(COX-2) and accumulation of PGE2 in aconcentration-dependent fashion. In addition, Melittin treatment induced the down-regulation of telomerase reverse transcriptase(hTERT) and proto-oncogene c-myc expression of A549 cells. Conclusions: Taken together, these findings suggest that melittin-induced inhibition of human lung cancer cell proliferation is associated with the induction of apoptotic cell death via regulation of several major growth regulatory gene products, and melittin may have therapeutic potential in human lung cancer.

• Molecules and Cells
• /
• v.27 no.3
• /
• pp.283-289
• /
• 2009

Curcumin, a natural compound extracted from rhizomes of curcuma Curcuma species, has been shown to possess potent anti-inflammatory, anti-tumor and anti-oxidative properties. However, the mechanism of action of the compound remains poorly understood. In this report, we have analyzed the effects of curcumin on the cell proliferation of Burkitt's lymphoma Raji cells. The results demonstrated that curcumin could effectively inhibit the growth of Raji cells in a dose- and time-dependent manner. Further studies indicated that curcumin treatment resulted in apoptosis of cells. Biochemical analysis showed that the expression of Bax, Bid and cytochrome C were up-regulated, while the expression of oncogene c-Myc was down regulated after curcumin treatment. Furthermore, poly (ADP-ribose) polymerase (PARP) cleavage was induced by the compound. Interestingly, the antiapoptotic Bcl-2 expression was not significantly changed in Raji cells after curcumin treatment. These results suggested that the mechanism of action of curcumin was to induce mitochondrial damage and therefore led to Raji cell apoptosis. We further investigated the in vivo effects of curcumin on the growth of xenograft tumors in nude mice. The results showed that curcumin could effectively inhibit tumor growth in the xenograft mouse model. The overall results showed that curcumin could suppress the growth of Burkitt's lymphoma cells in both in vitro and in vivo systems.

• Journal of Life Science
• /
• v.19 no.4
• /
• pp.502-507
• /
• 2009

In modern oriental medicine, bee venom therapy is being used for aqua-acupuncture to relieve pain and to cure inflammatory diseases such as rheumatoid arthritis, osteoarthritis, and gout. Bee venom therapy has been processed and reported in many experimental studies, with regard to its effects on pain alleviation, anti-inflammation, removal of fever, anti-convulsion, suppression of tumor and immunity strengthening, etc., however, its mechanism of action, molecular targeting on prostaglandin $E_2$ ($PGE_2$) production and telomere length regulation in human cancer remains unclear. In this study, we investigated the effect of bee venom on the levels of cyclooxygenases (COXs) and telomere regulatory components of A549 human lung cancer cells. Bee venom-induced anti-proliferative effects of A549 cells were associated with the inhibition of human telomerase reverse transcriptase (hTERT) as well as human telomerase RNA (hTR), transcription factor c-myc and the activity of telomerase. In addition, bee venom treatment markedly decreased the levels of COX-2 mRNA and protein expression without significant changes in the expression of COX-1, which was correlated with a decrease in $PGE_2$ synthesis. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-cancer activity of bee venom.

• The Journal of Korean Medicine
• /
• v.23 no.1
• /
• pp.24-36
• /
• 2002

Objectives: The chemotherapeutic potential of Gagamgilgyung-tang for the treatment of human lung cancer, the antitumorigenic effects of Gagamgilgyung-tang on the proliferation and apoptosis of human lung cancer cell line A427 were investigated using molecular biological approaches, Methods: To determine Gagamgilgyung-tang concentrations which do not evoke cytotoxic damage to the cell line, cell viability was examined by MTT assay. To prove Gagamgilgyung-tang's antitumorigenic potential to human lung cancer, [3H]thymidine incorporation assay, trypan blue exclusion and Cpp32 protease activity assays and quantitative RT-PCR analysis were examined. Results: While A427 cells treated with $0.1-2.0{\mu\textrm{g}}/ml$ of Gagamgilgyung-tang showed no recognizable effect, marked reductions of cell viability were detected at concentrations over $5.0{\;}\mu\textrm{g}/ml$. DNA replication of A427 cells was inhibited by Gagamgilgyung-tang in a dose-dependent manner and Gagamgilgyung-tang induced the G1 cell cycle arrest through inhibition of DNA replication. Gagamgilgyung-tang triggered apoptotic cell death of A427 and enhanced the apoptotic sensitivity of the cells that were injured by a DNA damage-inducing chemotherapeutic drug etoposide. Gagamgilgyung-tang induces expression of growth-inhibiting genes such as p53 and p21/Wafl whereas it inhibited expression of growth-promoting genes such as c-Myc and Cyclin D1. Expression of a representative apoptosis-inducing gene Bax was also found to be induced by Gagamgilgyung-tang while apoptosis-suppressing Bcl-2 expression was not changed. Conclusions: Gagamgilgyung-tang could suppress the abnormal growth of tumor cells by suppressing the survival of genetically altered cells via induction of apoptosis. This study suggests that Gagamgilgyung-tang might have an antitumorigenic potential to human lung cancer cells, which might be associated with its growth-inhibiting and apoptosis-inducing properties.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.1
• /
• pp.84-91
• /
• 2006

A Saccharomyces cerevisiae pgs1 nulI mutant, which is deficient with phosphatidyl glycerol (PG) and cardiolipin (CL) biosynthesis, grows well on most fermentable carbon sources, but fails to grow on non-fermentable carbon sources such as glycerol, ethanol, and lactate. This mutant also cannot grow on galactose medium as the sole carbon source. We found that the incorporation of $[^{14}C]-galactose$, which is the first step of the galactose metabolic pathway (Leloir pathway), into the pgs 1 null mutant cell was extremely repressed. Exogenously expressed PGS1 (YCpPGS1) under indigenous promoter could completely restore the pgs1 growth defect on non-fermentable carbon sources, and dramatically recovered $[^{14}C]-galactose$ incorporation into the pgs1 mutant cell. However, PGS1 expression under the GALl promoter $(YEpP_{GAL1}-PGS1myc)$ could not complement pgs1 mutation, and the GAL2-lacZ fusion gene $(YEpP_{GAL2}-lacZ)$ also did not exhibit its $\beta-galactosidase$ activity in the pgs1 mutant. In wild-type yeast, antimycin $A(1\;{\mu}g/ml)$, which inhibits mitochondrial complex III, severely repressed not only the expression of the GAL2-lacZ fusion gene, but also uptake of $[^{14}C]-galactose$. However, exogenously expressed PGS1 partially relieved these inhibitory effects of antimycin A in both the pgs1 mutant and wild-type yeast, although it could not basically restore the growth defect on galactose by antimycin A. These results suggest that the PGSI gene product has an important role in utilization of galactose by Gal genes, and that intact mitochondrial function with PGS1 should be required for galactose incorporation into the Leloir pathway. The PGS1 gene might provide a clue to resolve the historic issue about the incapability of galactose with deteriorated mitochondrial function.

• Biomedical Science Letters
• /
• v.15 no.4
• /
• pp.301-307
• /
• 2009

Whole-body insulin resistance results largely from impaired insulin-stimulated glucose disposal in skeletal muscle. Our previous studies using differential display and quantitative real-time RT-PCR have shown that a novel cDNA band (DD23) had a higher level of expression in insulin resistant skeletal muscle and it was correlated with whole-body insulin action, independent of age, sex, and percent body fat. In this study, we cloned and characterized DD23. The DD23 sequence is part of the 3'UTR region of the RNA binding motif, single stranded interacting protein (RBMS3). We have cloned the full length cDNA for RBMS3 and identified two splice variants. These variants named DD23-L and DD23-S have 15 and 14 exons respectively and differ from RBMS3 in the 3'UTR significantly. Northern blot analyses showed that an ~8.8 kb mRNA transcript of DD23 was predominantly expressed in skeletal muscle and to a lesser extent in placenta, but not in heart, brain, lung, liver, or kidney, unlike RBMS3. Elevated expression levels of these novel alternatively spliced variants of RBMS3 in skeletal muscle may play a role in whole body insulin resistance.

• Korean Journal of Medicinal Crop Science
• /
• v.12 no.4
• /
• pp.315-320
• /
• 2004

The purpose of this research was to investigate the effect of Orostachys japonicus A. Berger (OJB) on the immune system. Administration of OJB (500 mg/kg) enhanced viability of splenocytes and thymocytes in BALB/c mice, and also OJB increased of splenic T lymphocytes, significantly, increased CD4 positive $T_H$ cells and CD8 positive Tc cells. OJB markedly, enhanced the production of ${\gamma}-interferon$ in mice serum. OJB accelerated the apoptosis of L1210 and U937 leukemia cells and increased the expression of apoptosis-related ICE, c-myc, p53 gene. These results suggest that OJB have an immuno-regulatory and anti-cancer activity.

• Journal of Life Science
• /
• v.19 no.5
• /
• pp.620-624
• /
• 2009

D-Ala2-Leu5-enkephalin (DADLE), a hibernation inducer, can induce hibernation-like state in vivo and in vitro. We treated U937 human leukemia cancer cells with DADLE and investigated its possible effect on transcription and proliferation. Treatment of U937 cells with DADLE resulted in growth inhibition and induction of apoptotic cell death on high-dose as measured by MTT assay and DNA flow cytometer analysis. Bcl-XL, c-IAP-2 and survivin genes especially showed decreases in mRNA levels. DADLE treatment also inhibited the levels of cyclooxygenase (COX)-2 mRNA without alteration of COX-1 expression. DNA flow cytometer analysis revealed that DADLE caused arrest of the cell cycle on low-dose, which was associated with a down-regulation of cyclin E at the transcriptional level. DADLE treatment induced a marked down-regulation of cyclin-dependent kinase (Cdk)-2, -4 and -6. In addition, treatment with DADLE decreased telomere associated genes such as, c-myc and TERT, and increased TEP-1 in U937 cells. These results suggest that DADLE can be an inhibition agent in the cell cycle of the human leukemia cancer U937 cell.

• Journal of Life Science
• /
• v.24 no.9
• /
• pp.995-1000
• /
• 2014

The studies of marine viruses in terms of viral isolation and detection have been limited due to the high mutation rate and genetic diversity of marine viruses. Of the modern methods currently used to detect marine viruses, serological methods based on enzyme-linked immunosorbent assay (ELISA) are the most common. They depend largely on the quality of the antibodies and on highly purified suitable antigens. Recently, a new experimental system for using viral capsid protein as an antigen has been developed using the yeast surface display (YSD) technique. In the present study, the capsid protein gene of the red-spotted grouper nervous necrosis virus (RGNNV) was expressed and purified via YSD and HA-tagging systems, respectively. Two regions of the RGNNV capsid protein gene, RGNNV1 and RGNNV2, were individually synthesized and subcloned into a yeast expression vector, pCTCON. The expressions of each RGNNV capsid protein in the Saccharomyces cerevisiae strain EBY100 were indirectly detected by flow cytometry with fluorescently labeled antibodies, while recognizing the C-terminal c-myc tags encoded by the display vector. The expressed RGNNV capsid proteins were isolated from the yeast surface through the cleavage of the disulfide bond between the Aga1 and Aga2 proteins after ${\beta}$-mercaptoethanol treatment, and they were directly detected by Western blot using anti-HA antibody. These results indicated that YSD and HA-tagging systems could be applicable to the expressions and purification of recombinant RGNNV capsid proteins.