• BMB Reports
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• 제47권4호
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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.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3759-3765
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• 2015

Background: Approaches in disruption of MDM2-p53 interactions have now emerged as an important therapeutic strategy in resurrecting wild type p53 functional status. The present study highlights virtual screening strategies in identification of high affinity small molecule non-peptidic inhibitors. Nutlin3A and RG7112 belonging to compound class of Cis-imidazoline, MI219 of Spiro-oxindole class and Benzodiazepine derived TDP 665759 served as query small molecules for similarity search with a threshold of 95%. The query molecules and the similar molecules corresponding to each query were docked at the transactivation binding cleft of MDM2 protein. Aided by MolDock algorithm, high affinity compound against MDM2 was retrieved. Patch Dock supervised Protein-Protein interactions were established between MDM2 and ligand (query and similar) bound and free states of p53. Compounds with PubCid 68870345, 77819398, 71132874, and 11952782 respectively structurally similar to Nutlin3A, RG7112, Mi219 and TDP 665759 demonstrated higher affinity to MDM2 in comparison to their parent compounds. Evident from the protein-protein interaction studies, all the similar compounds except for 77819398 (similar to RG 7112) showed appreciable inhibitory potential. Of particular relevance, compound 68870345 akin to Nutlin 3A had highest inhibitory potential that respectively showed 1.3, 1.2, 1.16 and 1.26 folds higher inhibitory potential than Nutilin 3A, MI 219, RG 7112 and TDP 1665759. Compound 68870345 was further mapped for structure based pharamacophoric features. In the study, we report Cis-imidazoline derivative compound; Pubcid: 68870345 to have highest inhibitory potential in blocking MDM2-p53 interactions hitherto discovered.

• BMB Reports
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• 제51권10호
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• pp.526-531
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• 2018

Protein-Protein Interactions (PPIs) play essential roles in diverse biological processes and their misregulations are associated with a wide range of diseases. Especially, the growing attention to PPIs as a new class of therapeutic target is increasing the need for an efficient method of cell-based PPI analysis. Thus, we newly developed a robust PPI assay (SeePPI) based on the co-translocation of interacting proteins to the discrete subcellular compartment 'processing body' (p-body) inside living cells, enabling a facile analysis of PPI by the enriched fluorescent signal. The feasibility and strength of SeePPI (${\underline{S}}ignal$ ${\underline{e}}nhancement$ ${\underline{e}}xclusively$ on ${\underline{P}}-body$ for ${\underline{P}}rotein-protein$ ${\underline{I}}nteraction$) assay was firmly demonstrated with FKBP12/FRB interaction induced by rapamycin within seconds in real-time analysis of living cells, indicating its recapitulation of physiological PPI dynamics. In addition, we applied p53/MDM2 interaction and its dissociation by Nutlin-3 to SeePPI assay and further confirmed that SeePPI was quantitative and well reflected the endogenous PPI. Our SeePPI assay will provide another useful tool to achieve an efficient analysis of PPIs and their modulators in cells.

• Molecules and Cells
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• 제43권1호
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• pp.23-33
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• 2020

NF-κB signaling through both canonical and non-canonical pathways plays a central role in immune responses and inflammation. NF-κB-inducing kinase (NIK) stabilization is a key step in activation of the non-canonical pathway and its dysregulation implicated in various hematologic malignancies. The tumor suppressor, p53, is an established cellular gatekeeper of proliferation. Abnormalities of the TP53 gene have been detected in more than half of all human cancers. While the non-canonical NF-κB and p53 pathways have been explored for several decades, no studies to date have documented potential cross-talk between these two cancer-related mechanisms. Here, we demonstrate that p53 negatively regulates NIK in an miRNA-dependent manner. Overexpression of p53 decreased the levels of NIK, leading to inhibition of the non-canonical NF-κB pathway. Conversely, its knockdown led to increased levels of NIK, IKKα phosphorylation, and p100 processing. Additionally, miR-34b induced by nutlin-3 directly targeted the coding sequences (CDS) of NIK. Treatment with anti-miR-34b-5p augmented NIK levels and subsequent non-canonical NF-κB signaling. Our collective findings support a novel cross-talk mechanism between non-canonical NF-κB and p53.