• The Korean Journal of Physiology and Pharmacology
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• v.20 no.2
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• pp.161-168
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• 2016

Abnormal localization of tumor suppressor proteins is a common feature of renal cancer. Nuclear export of these tumor suppressor proteins is mediated by chromosome region maintenance-1 (CRM1). Here, we investigated the antitumor effects of a novel reversible inhibitor of CRM1 on renal cancer cells. We found that S109 inhibits the CRM1-mediated nuclear export of RanBP1 and reduces protein levels of CRM1. Furthermore, the inhibitory effects of S109 on CRM1 is reversible. Our data demonstrated that S109 significantly inhibits proliferation and colony formation of renal cancer cells. Cell cycle assay showed that S109 induced G1-phase arrest, followed by the reduction of Cyclin D1 and increased expression of p53 and p21. We also found that S109 induces nuclear accumulation of tumor suppressor proteins, Foxo1 and p27. Most importantly, mutation of CRM1 at Cys528 position abolished the effects of S109. Taken together, our results indicate that CRM1 is a therapeutic target in renal cancer and the novel reversible CRM1 inhibitor S109 can act as a promising candidate for renal cancer therapy.

• Laboraroty Animal Research
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• v.34 no.4
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• pp.264-269
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• 2018

Cell cycle dysfunction can cause severe diseases, including neurodegenerative disease and cancer. Mutations in cyclin-dependent kinase inhibitors controlling the G1 phase of the cell cycle are prevalent in various cancers. Mice lacking the tumor suppressors $p16^{Ink4a}$ (Cdkn2a, cyclin-dependent kinase inhibitor 2a), $p19^{Arf}$ (an alternative reading frame product of Cdkn2a,), and $p27^{Kip1}$ (Cdkn1b, cyclin-dependent kinase inhibitor 1b) result in malignant progression of epithelial cancers, sarcomas, and melanomas, respectively. Here, we generated knockout mouse models for each of these three cyclin-dependent kinase inhibitors using engineered nucleases. The $p16^{Ink4a}$ and $p19^{Arf}$ knockout mice were generated via transcription activator-like effector nucleases (TALENs), and $p27^{Kip1}$ knockout mice via clustered regularly interspaced short palindromic repeats/CRISPR-associated nuclease 9 (CRISPR/Cas9). These gene editing technologies were targeted to the first exon of each gene, to induce frameshifts producing premature termination codons. Unlike preexisting embryonic stem cell-based knockout mice, our mouse models are free from selectable markers or other external gene insertions, permitting more precise study of cell cycle-related diseases without confounding influences of foreign DNA.

• Molecular & Cellular Toxicology
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• v.2 no.3
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• pp.159-165
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• 2006

To determine the anticancer effect of D-amygdalin (D-mandelinitrole-${\beta}$-D-gentiobioside) in human chronic myeloid leukemia cells K562, we profiled the gene expression between amygdalin treatment and control groups. Through 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, the cytotoxicity of D-amygdalin was $57.79{\pm}1.83%$ at the concentration of 5 mg/mL for 24 h. We performed cDNA microarray analysis and compared the gene expression profiles between D-amygdalin (5 mg/mL, 24 h) treatment and control groups. Among the genes changed by D-amygdalin, we paid attention to cell cycle-related genes, and particularly cell cycle regulator genes; because arrest of cell cycle processing was ideal tactic in remedy for cancer. In our data, expressions of cyclin-dependent kinase inhibitor 1B (p27, Kip1) (CDKN1B), ataxia telangiectasia mutated (includes complementation groups A, C, and D) (ATM), cyclin-dependent kinase inhibitor 1C (p57, Kip2) (CDKN1C), and CHK1 checkpoint homolog (CHEK1, formally known as CHK1) were increased, while expressions of cyclin-dependent kinase 2 (CDK2), cell division cycle 25A (CDC25A), and cyclin E1 (CCNE1) were decreased. The pattern of these gene expressions were confirmed through RT-PCR. Our results showed that D-amygdalin might control cell cycle regulator genes and arrest S phase of cell cycle in K562 cells as the useful anticancer drug.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.91.2-91.2
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• 2003

Cyclin-dependent kinases (CDKs) regulate the cell division cycle, apoptosis, transcription and differentiation. Inhibition of CDK is a promising target in development of anti-cancer agents. An indirubin analog (AGM01l), a CDK inhibitor, is a synthetic compound that inhibits human cancer cell growth in vitro. AGM01l showed a potent cytotoxicity in cultured human cancer cell lines (IC$\sub$50/ = 5.43 ${\mu}$M for A549, human colon cancer cell; IC$\sub$50/ = 1.21 ${\mu}$M for SNU-638, human stomach cancer cell; IC$\sub$50/ 9.23 ${\mu}$M for HL-60, human leukemia cell). (omitted)

• Molecules and Cells
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• v.37 no.2
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• pp.126-132
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• 2014

As a tumor suppressor homologue during mitosis, Chk2 is involved in replication checkpoints, DNA repair, and cell cycle arrest, although its functions during mouse oocyte meiosis and early embryo development remain uncertain. We investigated the functions of Chk2 during mouse oocyte maturation and early embryo development. Chk2 exhibited a dynamic localization pattern; Chk2 expression was restricted to germinal vesicles at the germinal vesicle (GV) stage, was associated with centromeres at pro-metaphase I (Pro-MI), and localized to spindle poles at metaphase I (MI). Disrupting Chk2 activity resulted in cell cycle progression defects. First, inhibitor-treated oocytes were arrested at the GV stage and failed to undergo germinal vesicle breakdown (GVBD); this could be rescued after Chk2 inhibition release. Second, Chk2 inhibition after oocyte GVBD caused MI arrest. Third, the first cleavage of early embryo development was disrupted by Chk2 inhibition. Additionally, in inhibitor-treated oocytes, checkpoint protein Bub3 expression was consistently localized at centromeres at the MI stage, which indicated that the spindle assembly checkpoint (SAC) was activated. Moreover, disrupting Chk2 activity in oocytes caused severe chromosome misalignments and spindle disruption. In inhibitor-treated oocytes, centrosome protein ${\gamma}$-tubulin and Polo-like kinase 1 (Plk1) were dissociated from spindle poles. These results indicated that Chk2 regulated cell cycle progression and spindle assembly during mouse oocyte maturation and early embryo development.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7095-7100
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• 2013

Histone deacetylase (HDAC) inhibitors of cyclic peptide have been proved to be the most complex but the most stable and relative efficient inhibitors because of their large cap region. In this paper, a series of studies were carried out to evaluate the efficacy of synthetic bicyclic tetrapeptide inhibitors 1-5 containing hydroxamic acid referring molecular docking, anti-proliferation, morphology and apoptosis. Docking analysis, together with enzyme inhibitory results, verified the selective capability of inhibitor 4 to HDAC4, which might closely related to haematological tumorigenesis, with Phe227, Asp115, Pro32, His198 and Ser114 participating into hydrophobic interactions and Van der Waals force which was familiar with former study. Moreover, inhibitor 4 inhibited K562 cell line at the $IC_{50}$ value of 1.22 ${\mu}M$ which was 51-67 times more efficient than that for U937 and HL60 cell lines. Inhibitor 4 exhibited the cell cycle-arrested capability to leukemia at S phase or G2/M phase as well as apoptosis-induced ability in different degrees. Finally, we considered that bicyclic tetrapeptide inhibitors were promising inhibitors used in cancer treatment and inhibitor 4 could prevent K562 cell line well from proliferation, arrest cell cycle and induce K562 towards apoptosis to achieve the goals of reversing cancer cells which could become a potential leukemia therapeutic agent in the future.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.607-612
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• 2003

To elucidate the action mechanism of MCS-C2, a novel analogue of toyocamycin and sangivamycin, its effect on the expression of cell cycle-related proteins in the human myelocytic leukemia cell line HL-60 was examined using Western blotting and a flow cytometric analysis. MCS-C2, a selective inhibitor of cyclin-dependent kinases, was found to inhibit cell growth in a time- and dose-dependent manner, and inhibits cell cycle progression by inducing the arrest at G1 and G2/M phases, in HL-60 cells. The flow cytometric analysis revealed an appreciable arrest of cells in the G2/M phase of the cell cycle after treatment with MCS-C2. The HL-60 cell population increased gradually from 13% at 0 h, to 28% at 12 h in the G2/M phase, after exposure to $2{\;}\mu\textrm{M}$ MCS-C2. Furthermore, Western blot analysis demonstrated that MCS-C2 induced the cell cycle arrest at G1 phase through the inhibition of pRb phosphorylation. Hypophosphorylated pRb accumulated after treatment with $5{\;}\mu\textrm{M}$ MCS-C2 for 12 h, whereas, the level of hyperphosphorylated pRb was reduced. Thus, treatment of the cell with MCS-C2 suppressed the hyperphosphorylated form of pRb with a commensurate increase in the hypophosphorylated form.

• Journal of Life Science
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• v.15 no.5 s.72
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• pp.726-733
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• 2005

Histone deacetylase (HDAC) inhibitors target key steps of tumor development. They inhibit proliferation, induce differentiation and/or apoptotic cell death, and exhibit potent antimetastatic and antiangiogenic properties in cancer cells in vitro and in vivo. Although they are emerging as a promising new treatment strategy in malignancy, how they exert their effect on human non-small cell lung cancer cells is as yet unclear. The present study was undertaken to investiate the underlying mechanism of a HDAC inhibitor trichostatin A (TSA)-induced growth arrest and its effect on the cell cycle control gene products in a human lung carcinoma cell line A549. TSA treaoent induced the growth inhibition and morphological changes in a concentration-dependent manner. Treatment of A549 cells with TSA resulted in a concentration-dependent increased G1 (under 100 ng/ml) and/or G2/M (200 ng/ml) cell population of the cell cycle as determined by flow cytometry Moreover, 200 ng/ml TSA treatment significantly induced the population of sub-G1 cells (23.0 fold of control). This anti-proliferative effect of TSA was accompanied by a marked inhibition of cyclins, positive regulators of cell cycle progression, and cyclin-dependent kinases (Cdks) expression and concomitant induction of tumor suppressor p53 and Cdk inhibitors such as p21 and p27 Although further studies are needed, these findings provide important insights into the possible molecular mechanisms of the anti-cancer activity of TSA in human lung carcinoma cells.

• Molecules and Cells
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• v.24 no.3
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• pp.424-430
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• 2007

The biological effects of low-dose radiation have been investigated and debated for more than a century, but its cellular effects and regulatory mechanisms remain poorly understood. This study shows the human cellular responses to low-dose radiation in CCD-18 Lu cells, which are derived from normal human lung fibroblasts. We examined a colony-forming assay for cell survival by ionizing radiation. Live cell counting and cell cycle analysis were measured for cell proliferation and cell cycle progression following low-dose irradiation. We examined Raf and Akt phosphorylation to determine the proliferation mechanism resulting from low-dose radiation. We also observed that p53 and p21 were related to cell cycle response. We found that 0.05 Gy of ionizing radiation enhanced cell proliferation and did not change the progression of the cell cycle. In addition, 0.05 Gy of ionizing radiation transiently activated Raf and Akt, but did not change phospho-p53, p53 and p21 in CCD-18 Lu cells. However, 2 Gy of ionizing radiation induced cell cycle arrest, phosphorylation of p53, and expression of p53 and p21. The phosphorylation of Raf and Akt proteins induced by 0.05 Gy of ionizing radiation was abolished by pre-treatment with an EGFR inhibitor, AG1478, or a PI3k inhibitor, LY294002. Cell proliferation stimulated by 0.05 Gy of ionizing radiation was blocked by the suppression of Raf and Akt phosphorylation with these inhibitors. These results suggest that 0.05 Gy of ionizing radiation stimulates cell proliferation through the transient activation of Raf and Akt in CCD-18 Lu cells.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.965-970
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• 2015

Colorectal cancer is one of the most severe subtypes of cancer, and has the highest propensity to manifest as metastatic disease. Because of the lack of knowledge of events that correlate with tumor cell migration and invasion, few therapeutic options are available. The current study aimed to explore the mechanism of colorectal cancer in hope of identifying the ideal target for future treatment. We first discovered the pro-tumor effect of a controversial cell cycle regulator, cylin-dependent kinase inhibitor 3 (CDKN3), which is highly expressed in colorectal cancer, and the possible related signaling pathways, by bioinformatics tools. We found that CDKN3 had remarkable effects in suppressing colorectal cancer cell proliferation and migration, inducing cell cycle arrest and apoptosis in a colorectal cancer cell line, SW480 cells. Our study, for the first time, provided consistent evidence showing overexpression of cell cycle regulator CDKN3, in colorectal cancer. The in vitro studies in SW480 cells revealed a unique role of CDKN3 in regulating cellular behavior of colorectal cancer cells, and implied the possibility of targeting CDKN3 as a novel treatment for colorectal cancer.