Molecular docking, 3D-QASR and molecular dynamics simulations of thiazoles Pin1 inhibitors

Pin1 (protein interacting with never-in-mitosis akinase-1) is a member of the PPIase (peptidylprolyl cis-trans isomerase) family. It can interact with a variety of carcinogenic or tumor suppressive phosphorylated proteins. The interaction results in the conformational changes of target proteins, and ultimately regulates the activity of these proteins. These activity changes play a key role in tumorigenesis. Pin1 is an attractive target for cancer therapy due to its over-expression and/or activation in various types of cancer and the disorder of Proline directed phosphorylation. In this study, molecular docking, three-dimensional quantitative structure-activity relationship (3D-QSAR) and molecular dynamics (MD) simulations were performed to investigate the structure-activity relationship and binding mechanism of 45 thiazole-class Pin1 inhibitors. Molecular docking studies predict the binding mode and the interactions between the ligand and the receptor protein. The results of the 3 D-QSAR model show that electrostatic field, hydrophobic field and hydrogen bond play important roles in the binding process of inhibitors to protein. Molecular dynamics simulation results reveal that the complex of the ligand and the receptor protein are stable at 300 K. The binding free energy calculation and energy decomposition results show that His59, Cys113, Ser114, Ser115, Leu122, Met130, Gln131, Phe134, Ser154 and His157 may be the key to the inhibitor binding to Pin1 protein. This study provides an important theoretical basis for further development of the new Pin1 inhibitor design. These results can provide more useful information for our further drug design. Communicated by Ramaswamy H. Sarma.

Imazamethabenz inhibits human breast cancer cell proliferation, migration and invasion via combination with Pin1

Overexpression of peptidyl-prolyl cis/trans isomerase, NIMA interacting‑1 (Pin1) is a significant marker of the occurrence and development of tumors. In the present study, the imidazoline ketone herbicide imazamethabenz was investigated as a potential antitumor drug by inhibiting Pin1. Molecular docking and enzyme activity tests verified, for the first time, that the imidazoline ketone compound imazamethabenz effectively inhibited Pin1 in vitro. MTT assays, western blotting, wound healing assay and Matrigel invasion assays revealed that imazamethabenz induced apoptosis and inhibited migration and invasion of the breast cancer cell line MCF‑7, which overexpresses Pin1, by inhibiting the Pin1‑mediated signaling pathway involving vascular endothelial growth factor and matrix metalloproteinase 9. These findings indicated that imazamethabenz offers potential applications for the treatment of tumors as a Pin1 inhibitor.

[Parasites and cancer: is there a causal link?]

Over 20 % of cancers have infectious origins, including well-known examples of microbes such as viruses (HPV, EBV) and bacteria (H. pylori). The contribution of intracellular eukaryotic parasites to cancer etiology is largely unexplored. Epidemiological and clinical reports indicate that eukaryotic protozoan, such as intracellular apicomplexan that cause diseases of medical or economic importance, can be linked to various cancers: Theileria and Cryptosporidium induce host cell transformation while Plasmodium was linked epidemiologically to the "African lymphoma belt" over fifty years ago. These intracellular eukaryotic parasites hijack cellular pathways to manipulate the host cell epigenome, cellular machinery, signaling pathways and epigenetic programs and marks, such as methylation and acetylation, for their own benefit. In doing so, they tinker with the same pathways as those deregulated during cancer onset. Here we discuss how epidemiological evidence linking eukaryotic intracellular parasites to cancer onset are further strengthened by recent mechanistic studies in three apicomplexan parasites.

Pin1 is related with clinical stage of papillary thyroid carcinoma

Background

The context and aim of this article was to investigate whether the expression level of Pin1 was in association with the clinical stage of papillary thyroid carcinomas.

Methods

Seventy-two patients who had been treated at the Affiliated Hospital of Qingdao University – Yantai YuHuangDing Hospital during January 2013 to December 2014 were rolled in. The expression levels of Pin1 using immunohistochemistry were tested and were divided into four groups according to the different clinical stages and final scores based on multiplying intensity and percentage value of IHC results. Data was analyzed with SPSS 20.0, and P value <0.05 had been chosen as significant.

Results

Considered from analysis result, the Pin1 expression status statistically significantly correlated with the PTC clinical stages (χ² = 8.128, P = 0.043); as the clinical stage proceeded, the intensity of Pin1 in PTC cells had been increased. But we did not find any relationships between immunohistochemical staining results and other clinicopathological characteristics.

Conclusions

The PTC cells’ intensity of Pin1 was in association with the clinical stage. The role played by Pin1 in PTC has been studied, and we need to further investigate the application of Pin1 in the treatment of PTC.

Targeting Pin1 Protects Mouse Cardiomyocytes from High-Dose Alcohol-Induced Apoptosis

Long-term heavy alcohol consumption is considered to be one of the main causes of left ventricular dysfunction in alcoholic cardiomyopathy (ACM). As previously suggested, high-dose alcohol induces oxidation stress and apoptosis of cardiomyocytes. However, the underlying mechanisms are yet to be elucidated. In this study, we found that high-dose alcohol treatment stimulated expression and activity of Pin1 in mouse primary cardiomyocytes. While siRNA-mediated knockdown of Pin1 suppressed alcohol-induced mouse cardiomyocyte apoptosis, overexpression of Pin1 further upregulated the numbers of apoptotic mouse cardiomyocytes. We further demonstrated that Pin1 promotes mitochondria oxidative stress and loss of mitochondrial membrane potential but suppresses endothelial nitric oxide synthase (eNOS) expression in the presence of alcohol. Taken together, our results revealed a pivotal role of Pin1 in regulation of alcohol-induced mouse cardiomyocytes apoptosis by promoting reactive oxygen species (ROS) accumulation and repressing eNOS expression, which could be potential therapeutic targets for ACM.

[NADPH oxidases, Nox: new isoenzymes family]

NADPH oxidases, Nox, are a family of isoenzymes, composed of seven members, whose sole function is to produce reactive oxygen species (ROS). Although Nox catalyze the same enzymatic reaction, they acquired from a common ancestor during evolution, specificities related to their tissue expression, subcellular localization, activation mechanisms and regulation. Their functions could vary depending on the pathophysiological state of the tissues. Indeed, ROS are not only bactericidal weapons in phagocytes but also essential cellular signaling molecules and their overproduction is involved in chronic diseases and diseases of aging. The understanding of the mechanisms involved in the function of Nox and the emergence of Nox inhibitors, require a thorough knowledge of their nature and structure. The objectives of this review are to highlight, in a structure/function approach, the main similar and differentiated properties shared by the human Nox isoenzymes.

[Implication of PML nuclear bodies in intrinsic and innate immunity]

PML/TRIM19 is the organizer of PML nuclear bodies (NB), large multiprotein structures associated to the nuclear matrix, which recruit a great number of proteins and which are implicated in various cellular processes including antiviral defense. The conjugation of PML to SUMO is required for the formation and function of PML NB. Alternative splicing from a single PML gene generates several PML isoforms (PMLI to PMLVIIb), each harboring a specific carboxy-terminal region. This variability allows each isoform to recruit different partners and thus confers them specific functions. PML gene is directly induced by interferon and certain PML isoforms are implicated in its antiviral properties, as they display intrinsic antiviral activities against RNA or DNA viruses. One isoform, PMLIV, is also implicated in innate immunity by enhancing IFN-β production during a viral infection. Here we review recent findings on PML/TRIM19 implication in interferon response and antiviral defense, at the interface between intrinsic and innate immunity.