• Biomolecules & Therapeutics
• /
• v.20 no.3
• /
• pp.313-319
• /
• 2012

In recent years, inhibition of HDACs has emerged as a potential strategy to reverse aberrant epigenetic changes associated with cancer, and several classes of HDAC inhibitors have been found to have potent and specific anticancer activities in preclinical studies. But their precise mechanism of action has not been elucidated. In this study, a novel synthetic inhibitor of HDAC, 3-(4-dimethylamino phenyl)-N-hydroxy-2-propenamide [IN-2001] was examined for its antitumor activity and the underlying molecular mechanisms of any such activity on human breast cancer cell lines. IN-2001 effectively inhibited cellular HDAC activity ($IC_{50}$ = 0.585 nM) inMDA-MB-231 human breast cancer cells. IN-2001 caused a significant dose-dependent inhibition of cell proliferation in estrogen receptor (ER) negative MDA-MB-231human breast cancer cells. Cell cycle analysis revealed that the growth inhibitory effects of IN-2001 might be attributed to cell cycle arrest at $G_0/G_1$ and/or $G_2$/Mphase and subsequent apoptosis in human breast cancer cells. These events are accompanied by modulating several cell cycle and apoptosis regulatory genes such as CDK inhibitors $p21^{WAF1}$ and $p27^{KIP1}$ cyclin D1, and other tumor suppressor genes such as cyclin D2. Collectively, IN-2001 inhibited cell proliferation and induced apoptosis in human breast cancer cells and these findings may provide new therapeutic approaches, combination of antiestrogen together with a HDAC inhibitor, in the hormonal therapy-resistant ER-negative breast cancers. In summary, our data suggest that this histone deacetylase inhibitor, IN-2001, is a novel promising therapeutic agent with potent antitumor effects against human breast cancers.

• Journal of the Korean Magnetic Resonance Society
• /
• v.23 no.1
• /
• pp.20-25
• /
• 2019

The transcription factor CP2c has been recently validated as an oncogenic protein that can serve as a promising target for anticancer therapy. We have recently documented that a recombinant protein corresponding to the putative DNA-binding region (residues 63-244) of CP2c adopted two different conformers, one of which is dominated by zinc binding. However, in the present study, a longer construct encompassing residues 63-302 appeared to form a single structural domain. This domain could be considered to adopt a functionally relevant fold, as the known specific binding of a dodecapeptide to this protein was evident. Hence, the residues 63-302 region rather than 63-244 can be regarded as a natively folded structural domain of CP2c. In addition, it was confirmed that zinc ions can bind to this putative DNA-binding domain of CP2c, which resulted in reduced stability of the protein. In this context, it is suggested that the mode of action of CP2c would resemble that of tumor suppressor p53.

• Animal Bioscience
• /
• v.34 no.1
• /
• pp.143-153
• /
• 2021

Objective: To explore the molecular mechanisms of fatty liver hemorrhagic syndrome (FLHS) in laying hens, an experiment was conducted to reveal the differences in histopathological observation and gene expression between FLHS group and normal group. Methods: We compared the histopathological difference using hematoxylin and eosin staining and proceeded with RNA sequencing of adipose tissue to search differentially expressed genes and enriched biological processes and pathways. Then we validated the mRNA expression levels by real-time polymerase chain reaction and quantified protein levels in the circulation by enzyme-linked immunosorbent assay. Results: We identified 100 differentially expressed transcripts corresponding to 66 genes (DEGs) were identified between FLHS-affected group and normal group. Seven DEGs were significantly enriched in the immune response process and lipid metabolic process, including phospholipase A2 group V, WAP kunitz and netrin domain containing 2, delta 4-desaturase sphingolipid 2, perilipin 3, interleukin-6 (IL-6), ciliary neurotrophic factor (CNTF), and suppressor of cytokine signaling 3 (SOCS3). And these genes could be the targets of immune response and be involved in metabolic homeostasis during the process of FLHS in laying hens. Based on functional categories of the DEGs, we further proposed a model to explain the etiology and pathogenesis of FLHS. IL-6 and SOCS3 mediate inflammatory responses and the satiety hormone of leptin, induce dysfunction of Jak-STAT signaling pathway, leading to insulin resistance and lipid metabolic disorders. Conversely, CNTF may reduce tissue destruction during inflammatory attacks and confer protection from inflammation-induced insulin resistance in FLHS chickens. Conclusion: These findings highlight the therapeutic implications of targeting the JAK-STAT pathway. Inhibition of IL6 and SOCS3 and facilitation of CNTF could serve as a favorable strategy to enhance insulin action and improve glucose homoeostasis, which are of importance for treating obesity-related disorders for chickens.

• Journal of Life Science
• /
• v.16 no.4
• /
• pp.589-597
• /
• 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
• /
• v.15 no.19
• /
• pp.8377-8382
• /
• 2014

Background: Oral squamous cell carcinoma (OSCC) is the sixth most common malignancy worldwide. Cancer development and progression require inactivation of tumor suppressor genes and activation of proto-oncogenes. The well recognized mechanism of action demonstrated for chemotherapeutic agents is induction of apoptosis via reactivation of p53. In this context, we evaluate the efficacy of IV and oral routes of our novel PH and temperature sensitive doxorubicin-methotrexate-loaded nanoparticles (DOX-MTX NP) in affecting p53 profile in an OSCC rat model. Methods: In this study, 120 male rats were divided into 8 groups of 15 animals each. The new formulated DOX-MTX NP and free doxorubicin were IV and orally given to rats with 4-nitroquinoline-1-oxide induced OSCC. Results: Results showed that both DOX and DOX-MTX-NP caused significant increase in mRNA levels of P53 compared to the untreated group (p<0.000). With both DOX and DOX-MTX NP, the IV mode was more effective than the oral (gavage) route (p<0.000). Surprisingly, in oral mode, p53 mRNA was not affected in DOX treated groups (p>0.05), Nonetheless, both IV and oral administration of MTX-DOX NP showed superior activity (~3 fold) over free DOX in reactivation of p53 in OSCC (p<0.000). The effectiveness of oral route in group treated with nanodrug accounts for the enhanced bioavailability of nanoparticulated DOX-MTX compared to free DOX. Moreover, in treated groups, tumor stage was markedly related to the amount of p53 mRNA (p<0.05). Conclusion: Both oral and IV application of our novel nanodrug possesses superior activity over free DOX-in up-regulation of p53 in a OSCC model and this increase in p53 level associated with less aggressive tumors in our study. Although, impressive results obtained with IV form of nanodrug (-21 fold increase in p53 mRNA level) but both forms of nanodrug are effective in OSCC, with less toxicity normal cells.

• Korean Journal of Head & Neck Oncology
• /
• v.17 no.2
• /
• pp.169-173
• /
• 2001

Objectives: The p53 tumor suppressor gene encodes a nuclear transcription factor that is critical regulator of cell growth and proliferation through its action in cell-cycle checkpoint control. The wide variety of stressful stmuli which include DNA damage, hypoxia, heat shock, metabolic changes activate the p53 protein, which in turn drives a series of events that culminate either in cell cycle arrest or apoptosis. Mutations of the p53 gene is the most common genetic alteration in human cancer. This gene is altered in approximately 40-60% of head and neck cancers. Whereas the wild-type form of the p53 protein plays a central role in cell-cycle control in response to DNA damage, most of the mutant forms are unable to do so. The high levels of p53 protein expression in tissues are related to the increased cellular proliferative activity and may be associated with the poor clinical outcome. To determine whether the expression of the p53 protein has prognostic significance and is associated with patterns of treatment failure in head and neck squamous cell carcinoma (HNSCC), We analyzed p53 overexpression in 40 cases of HNSCC. Materials and Methods: Immunohistochemical analysis with a monoclonal antibody (DO7) specific for p53 protein was used to detect expression of the protein in formalin-fixed, paraffin-embedded tumor samples from 40 HNSCC. We evaluated p53 protein expression and analyzed the relationship between the p53 overexpression and age, sex, primary tumor site, stage, survival rate, recurrence. All reported P values resulted from two-sided statistical tests. Results: Overexpression of p53 was detected in 20 cases(50%) among 40 cases of HNSCC. The p53 overexpression was not associated with age, sex, primary tumor site, stage, recurrence and survival rate. Conclusions: In our results, p53 was not significant prognostic factor in HNSCC. Based on many previous studies, It is evident that p53 has a certain role in tumorigenesis of HNSCC. So, the further study is needed to evaluate the prognostic significance of p53 in HNSCC.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.12
• /
• pp.4809-4813
• /
• 2014

Endocrine-disrupting chemicals (EDCs) have been reported to interfere with estrogen signaling. Exposure to these chemicals decreases the immune response and causes a wide range of diseases in animals and humans. Recently, many studies showed that licorice (Glycyrrhiza glabra) root extract (LRE) commonly called "gamcho" in Korea exhibits antioxidative, chemoprotective, and detoxifying properties. This study aimed to investigate the mechanism of action of LRE and to determine if and how LRE can alleviate the toxicity of EDCs. LRE was prepared by vacuum evaporation and freeze-drying after homogenization of licorice root powder that was soaked in 80% ethanol for 72 h. We used 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as a representative EDC, which is known to induce tumors or cancers; MCF-7 breast cancer cells, used as a tumor model, were treated with TCDD and various concentrations of LRE (0, 50, 100, 200, $400{\mu}g/mL$) for 24, 48, and 72 h. As a result, TCDD stimulated MCF-7 cell proliferation, but LRE significantly inhibited TCDD-induced MCF-7 cell proliferation in a dose- and time-dependent manner. The expression of TCDD toxicity-related genes, i.e., aryl hydrocarbon receptor (AhR), AhR nuclear translocator, and cytochrome P450 1A1, was also down-regulated by LRE in a dose-dependent manner. Analysis of cell cycle distribution after treatment of MCF-7 cells with TCDD showed that LRE inhibited the proliferation of MCF-7 cells via G2/M phase arrest. Reverse transcription-polymerase chain reaction and Western blot analysis also revealed that LRE dose-dependently increased the expression of the tumor suppressor genes p53 and p27 and down-regulated the expression of cell cycle-related genes. These data suggest that LRE can mitigate the tumorigenic effects of TCDD in breast cancer cells by suppression of AhR expression and cell cycle arrest. Thus, LRE can be used as a potential toxicity-alleviating agent against EDC-mediated diseases.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.12
• /
• pp.4969-4976
• /
• 2014

Background: miR-152 is involved in the genesis and development of several malignancies. However, its role in HCC has not been fully clarified. The aim of this study was to investigate the clinicopathological significance of miR-152 and its effect on the malignant phenotype of HCC cells. Methods: miR-152 expression was detected using real-time quantitative RT-PCR in 89 pairs of HCC formalin-fixed paraffin-embedded and their adjacent tissues. Functionally, in vitro effects and mechanisms of action of miR-152 on proliferation, viability, caspase activity, apoptosis and motility were explored in HepG2, HepB3 and SNU449 cells, as assessed by spectrophotometry, fluorimetry, fluorescence microscopy, wound-healing and Western blotting, respectively. Results: miR-152 expression in HCC was downregulated remarkably compared to that in adjacent hepatic tissues. miR-152 levels in groups of advanced clinical stage, larger tumor size and positive HBV infection, were significantly lower than in other groups. A miR-152 mimic could suppress cell growth, inhibit cell motility and increase caspase activity and apoptosis in HCC cell lines. Furthermore, Western blotting showed that the miR-152 mimic downregulated Wnt-1, DNMT1, ERK1/2, AKT and TNFRS6B signaling. Intriguingly, inverse correlation of TNFRF6B and miR-152 expression was found in HCC and bioinformatics confirmed that TNFRF6B might be a target of miR-152. Conclusions: Underexpression of miR-152 plays a vital role in hepatocarcinogenesis and lack of miR-152 is related to the progression of HCC through deregulation of cell proliferation, motility and apoptosis. miR-152 may act as a tumor suppressor miRNA by also targeting TNFRSF6B and is therefore a potential candidate biomarker for HCC diagnosis, prognosis and molecular therapy.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.13
• /
• pp.5117-5121
• /
• 2014

Endocrine-disrupting chemicals (EDCs) have been reported to interfere with estrogen signaling. Exposure to these chemicals decreases the immune response and causes a wide range of diseases in animals and humans. Recently, many studies showed that licorice (Glycyrrhiza glabra) root extract (LRE) commonly called "gamcho" in Korea exhibits antioxidative, chemoprotective, and detoxifying properties. This study aimed to investigate the mechanism of action of LRE and to determine if and how LRE can alleviate the toxicity of EDCs. LRE was prepared by vacuum evaporation and freeze-drying after homogenization of licorice root powder that was soaked in 80% ethanol for 72 h. We used 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as an EDC, which is known to induce tumors or cancers; MCF-7 breast cancer cells were used as a tumorigenic model. These were treated with TCDD and various concentrations of LRE (0, 50, 100, 200, $400{\mu}g/mL$) for 24, 48, and 72 h. As a result, TCDD stimulated MCF-7 cell proliferation, but LRE significantly inhibited TCDD-induced MCF-7 cell proliferation in a dose- and time-dependent manner. Expression of TCDD toxicity-related genes, i.e., aryl hydrocarbon receptor (AhR), AhR nuclear translocator, and cytochrome P450 1A1, were subsequently down-regulated by LRE in a dose-dependent manner. Analysis of cell cycle distribution after treatment of MCF-7 cells with TCDD and various concentrations of LRE showed that LRE inhibited the proliferation of MCF-7 cells via G2/M phase arrest. Reverse transcription-polymerase chain reaction and Western blot analyses also revealed that LRE dose-dependently increased the expression of the tumor suppressor genes p53 and p27 and down-regulated the expression of cell cycle-related genes. These data suggest that LRE can mitigate the tumorigenic effects of TCDD in breast cancer cells by suppression of AhR expression and cell cycle arrest. Thus, LRE can be used as a potential toxicity-alleviating agent against EDC-mediated disease.

• Journal of Life Science
• /
• v.18 no.3
• /
• pp.336-343
• /
• 2008

Histone deacetylases (HDACs) inhibitors have emerged as the accessory therapeutic agents for various human cancers, since they can block the activity of specific HDACs, restore the expression of some tumor suppressor genes and induce cell differentiation, cell cycle arrest and apoptosis in vitro and in vivo. In the present study, we investigated that the effect of trichostatin A (TSA), an HDAC inhibitor, on the cell growth and apoptosis, and its effect on the nuclear factor-kappaB $(NF-{\kappa}B)$ activity in 267B1 human prostate epithelial cells. Exposure of 267B1 cells to TSA resulted in growth inhibition and apoptosis induction in and dose-dependent manners as measured by fluorescence microscopy, agarose gel electrophoresis and flow cytometry analysis. TSA treatment inhibited the levels of IAP family members such as c-IAP-1 and c-IAP-2 and induced the proteolytic activation of caspase-3, -8 and -9, which were associated with concomitant degradation of poly (ADP-ribose)-polymerase, ${\beta}-catenin$ and laminin B proteins. The increase in apoptosis by TSA was connected with the translocation of $NF-{\kappa}B$ from cytosol to nucleus, increase of the DNA binding as well as promoter activity of $NF-{\kappa}B$, and degradation of cytosolic inhibitor of KappaB $(I{\kappa}B)-{\alpha}$ protein. We therefore concluded that TSA demonstrated anti-proliferative and apoptosis-inducing effects on 267B1 cells in vitro, and that the activation of caspases and $NF-{\kappa}B$ may play important roles in its mechanism of action. Although further studies are needed, these findings provided important insights into the possible molecular mechanisms of the anti-cancer activity of TSA.