• Journal of Life Science
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• v.31 no.4
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• pp.400-409
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• 2021

Sanguinarine, a natural benzophenanthridine alkaloid, has been considered a potential therapeutic target for the treatment of cancer because it can induce apoptosis in human cancer cells; however, the underlying mechanisms of action still remain unclear. Tumor suppressor p53 deletion or mutation is an important reason for the resistance of colorectal cancer cells to anticancer agents. Therefore, in the present study, the role of p53 during apoptosis induced by sanguinarine was investigated in p53wild type (WT, p53+/+) and p53null (p53+/+) HCT116 colon carcinoma cells. Sanguinarine significantly caused greater reductions in cell viability in HCT116 (p53+/+) cells than in HCT116 (p53-/-) cells. Consistently, sanguinarine promoted more DNA damage and apoptosis in HCT116 (p53+/+) cells than in HCT116 (p53-/-) cells while increasing the expression of p53 and cyclin-dependent kinase inhibitor p21^WAF1/CIP1. Sanguinarine increased the activity of caspase-8 and caspase-9, which are involved in the initiation of extrinsic and intrinsic apoptosis pathways, respectively, and it activated caspase-3, a typical effect caspase, in HCT116 (p53+/+) cells. Sanguinarine also increased the generation of reactive oxygen species (ROS), and the Bax/Bcl-2 ratio, while destroying the integrity of mitochondria in HCT116 (p53+/+) cells, but not in HCT116 (p53-/-) cells. Overall, the results indicate that sanguinarine induced p53-dependent apoptosis through ROS-mediated activation of extrinsic and intrinsic apoptotic pathways in HCT116 colorectal cancer cells.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.418-422
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• 2015

In the course of screening for novel cell cycle inhibitors and apoptotic inducers, CR389, elucidated as 5-(1H-benzoimidazol-2-yl)-1H-pyridin-2-one, was generated as a new hit compound. Flow cytometric analysis and western blots of PA-1 cells treated with $60{\mu}M$ CR389 revealed an appreciable cell cycle arrest at the G2/M phase through direct inhibition of the CDK1 complex. In addition, activation of p53 via phosphorylation at Ser15 and subsequent up-regulation of p21^CIP1 showed that CR389 also induces p53-dependent-p21^CIP1-mediated cell cycle arrest. Furthermore, apoptotic induction in $60{\mu}M$ CR389-treated PA-1 cells is associated with the release of cytochrome c from mitochondria through up-regulation of the proapoptotic Bax protein, which results in the activation of procaspase-9 and -3, and the cleavage of poly(ADP-ribose) polymerase (PARP). Accordingly, CR389 seems to have multiple mechanisms of antiproliferative activity through p53-mediated pathways against human ovarian cancer cells. Therefore, we conclude that CR389 is a candidate therapeutic agent for the treatment of human ovarian cancer via the activation of p53.

• BMB Reports
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• v.53 no.4
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• pp.229-233
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• 2020

The anti-colorectal cancer monoclonal antibody CO17-1A (mAb CO), which recognizes the tumor-associated antigen EpCAM, was expressed in transgenic Arabidopsis plants. PCR and western blot analyses showed the insertion and expression of heavy chain (HC)/HC fused to the KDEL ER retention modif (HCK) and light chain (LC) of mAb CO and mAb CO with HCK (mAb COK) in Arabidopsis transformants. Both plant-derived mAb^P CO and mAb^P COK were purified from a biomass of approximately 1,000 seedlings grown in a greenhouse. In sandwich ELISA, both mAb^P CO showed a slightly higher binding affinity for the target, EpCAM, compared to mAb^M CO. In cell ELISA, both mAbs^P COs showed binding affinity to the human colorectal cancer cell line SW480. Furthermore, mAb^M CO, mAb^P CO, and mAb^P COK exhibited dose and timedependent regression effects on SW480 cells in vitro. In summation, both mAb^P CO and mAb^P COK, expressed in Arabidopsis, recognized the target antigen EpCAM and showed anti-proliferative activity against human colorectal cancer cells.

• BMB Reports
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• v.47 no.4
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• pp.221-226
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• 2014

Drug-resistance and imbalance of apoptotic regulation limit chemotherapy clinical application for the human hepatocellular carcinoma (HCC) treatment. The reactivation of p53 is an attractive therapeutic strategy in cancer with disrupted-p53 function. Nutlin-3, a MDM2 antagonist, has antitumor activity in various cancers. The post-translational modifications of p53 are a hot topic, but there are some controversy ideas about the function of phospho-$Ser^{392}$-p53 protein in cancer cell lines in response to Nutlin-3. Therefore, we investigated the relationship between Nutlin-3 and phospho-$Ser^{392}$-p53 protein expression levels in SMMC-7721 (wild-type TP53) and HuH-7 cells (mutant TP53). We demonstrated that Nutlin-3 induced apoptosis through down-regulation phospho-$Ser^{392}$-p53 in two HCC cells. The result suggests that inhibition of p53 phosphorylation on $Ser^{392}$ presents an alternative for HCC chemotherapy.

• Molecules and Cells
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• v.28 no.5
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• pp.489-494
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• 2009

We have previously shown that the down-regulation of protein kinase CKII activity is tightly associated with cellular senescence of human fibroblast IMR-90 cells. Here, we examined the roles of p53 and $p21^{Cip1/WAF1}$ in senescence development induced by CKII inhibition using wild-type, isogenic p53-/- and isogenic p21-/- HCT116 human colon cancer cell lines. A senescent marker appeared after staining for senescence-associated ${\beta}$-galactosidase activity in wild-type HCT116 cells treated with CKII inhibitor or $CKII{\alpha}$ siRNA, but this response was almost abolished in p53- or $p21^{Cip1/WAF1}$-null cells. Increased cellular levels of p53 and $p21^{Cip1/WAF1}$ protein occurred with the inhibition of CKII. CKII inhibition upregulated p53 and $p21^{Cip1/WAF1}$ expression at post-transcriptional level and transcription level, respectively. RB phosphorylation significantly decreased in cells treated with CKII inhibitor. Taken together, this study shows that the activation of the $p53-p21^{Cip1/WAF1}$ pathway acts as a major mediator of cellular senescence induced by CKII inhibition.

• Kyungpook Mathematical Journal
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• v.14 no.1
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• pp.45-53
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• 1974

• Bulletin of the Korean Mathematical Society
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• v.15 no.2
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• pp.53-57
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• 1979

• BMB Reports
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• v.53 no.5
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• pp.272-277
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• 2020

Protein kinase CK2 downregulation induces premature senescence in various human cell types via activation of the reactive oxygen species (ROS)-p53-p21^Cip1/WAF1 pathway. The transcription factor "nuclear factor erythroid 2-related factor 2" (Nrf2) plays an important role in maintaining intracellular redox homeostasis. In this study, Nrf2 overexpression attenuated CK2 downregulation-induced ROS production and senescence markers including SA-β-gal staining and activation of p53-p21^Cip1/WAF1 in human breast (MCF-7) and colon (HCT116) cancer cells. CK2 downregulation reduced the transcription of Nrf2 target genes, such as glutathione S-transferase, glutathione peroxidase 2, and glutathione reductase 1. Furthermore, CK2 downregulation destabilized Nrf2 protein via inhibiting autophagic degradation of Kelch-like ECH-associated protein 1 (Keap1). Finally, CK2 downregulation decreased the nuclear import of Nrf2 by deactivating AMP-activated protein kinase (AMPK). Collectively, our data suggest that both Keap1 stabilization and AMPK inactivation are associated with decreased activity of Nrf2 in CK2 downregulation-induced cellular senescence.

• BMB Reports
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• v.49 no.9
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• pp.497-501
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• 2016

Wide-line ¹H NMR intensity and differential scanning calorimetry measurements were carried out on the intrinsically disordered 73-residue full transactivation domain (TAD) of the p53 tumor suppressor protein and two peptides: one a wild type p53 TAD peptide with a helix pre-structuring property, and a mutant peptide with a disabled helix-forming propensity. Measurements were carried out in order to characterize their water and ion binding characteristics. By quantifying the number of hydrate water molecules, we provide a microscopic description for the interactions of water with a wild-type p53 TAD and two p53 TAD peptides. The results provide direct evidence that intrinsically disordered proteins (IDPs) and a less structured peptide not only have a higher hydration capacity than globular proteins, but are also able to bind a larger amount of charged solute ions.

• BMB Reports
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• v.55 no.2
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• pp.92-97
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• 2022

Lysine methylation is one of the most important histone modifications that modulate chromatin structure. In the present study, the roles of the histone lysine demethylases JMJD2a and LSD1 in CK2 downregulation-mediated senescence were investigated. The ectopic expression of JMJD2a and LSD1 suppressed the induction of senescence-associated β-galactosidase activity and heterochromatin foci formation as well as the reduction of colony-forming and cell migration ability mediated by CK2 knockdown. CK2 downregulation inhibited JMJD2a and LSD1 expression by activating the mammalian target of rapamycin (mTOR)-ribosomal p70 S6 kinase (p70S6K) pathway. In addition, the down-regulation of JMJD2a and LSD1 was involved in activating the p53-p21^Cip1/WAF1-SUV39h1-trimethylation of the histone H3 Lys9 (H3K9me3) pathway in CK2-downregulated cells. Further, CK2 downregulation-mediated JMJD2a and LSD1 reduction was found to stimulate the dimethylation of Lys370 on p53 (p53K370me2) and nuclear import of SUV39h1. Therefore, this study indicated that CK2 downregulation reduces JMJD2a and LSD1 expression by activating mTOR, resulting in H3K9me3 induction by increasing the p53K370me2-dependent nuclear import of SUV39h1. These results suggest that CK2 is a potential therapeutic target for age-related diseases.