AICAR and compound C negatively modulate HCC-induced primary human hepatic stellate cell activation in vitro

Tumour stroma and microenvironment have been shown to affect hepatocellular carcinoma (HCC) growth, with activated hepatic stellate cells (HSC) as a major contributor in this process. Recent evidence suggests that the energy sensor adenosine monophosphate-activated kinase (AMPK) may mediate a series of essential processes during carcinogenesis and HCC progression. Here, we investigated the effect of different HCC cell lines with known TP53 or CTNBB1 mutations on primary human HSC activation, proliferation and AMPK activation. We show that conditioned media obtained from multiple HCC cell lines differently modulate human hHSC proliferation and hHSC AMPK activity in a paracrine manner. Pharmacological treatment of hHSC with AICAR and Compound C inhibited the HCC-induced proliferation/activation of hHSC through AMPK-dependent and AMPK-independent mechanisms, which was further confirmed using mouse embryonic fibroblasts (MEFs) deficient of both catalytic AMPKα isoforms (AMPKα1/α2-/-) and wild type (wt) MEF. Both compounds induced S-phase cell-cycle arrest and, in addition, AICAR inhibited the mTORC1 pathway by inhibiting phosphorylation of 4E-BP1 and S6 in hHSC and wt MEF. Datamining of the Cancer Genome Atlas (TCGA) and the Liver Cancer (LICA-FR) showed that AMPKα1 (PRKAA1) and AMPKα2 (PRKAA2) expression differed depending on the mutation (TP53 or CTNNB1), tumour grading and G1-G6 classification, reflecting the heterogeneity in human HCC. Overall, we provide evidence that AMPK modulating pharmacological agents negatively modulate HCC-induced hHSC activation and may therefore provide a novel approach to target the mutual, tumour-promoting interactions between hHSC and HCC

Tamoxifen mechanically deactivates hepatic stellate cells via the G protein-coupled estrogen receptor

Tamoxifen has been used for many years to target estrogen receptor signalling in breast cancer cells. Tamoxifen is also an agonist of the G protein-coupled estrogen receptor (GPER), a GPCR ubiquitously expressed in tissues that mediates the acute response to estrogens. Here we report that tamoxifen promotes mechanical quiescence in hepatic stellate cells (HSCs), stromal fibroblast-like cells whose activation triggers and perpetuates liver fibrosis in hepatocellular carcinomas. This mechanical deactivation is mediated by the GPER/RhoA/myosin axis and induces YAP deactivation. We report that tamoxifen decreases the levels of hypoxia-inducible factor-1 alpha (HIF-1α) and the synthesis of extracellular matrix proteins through a mechanical mechanism that involves actomyosin-dependent contractility and mechanosensing of tissue stiffness. Our results implicate GPER-mediated estrogen signalling in the mechanosensory-driven activation of HSCs and put forward estrogenic signalling as an option for mechanical reprogramming of myofibroblast-like cells in the tumour microenvironment. Tamoxifen, with half a century of safe clinical use, might lead this strategy of drug repositioning.Peer reviewe

HIV-PDI: A protein drug interaction resource for structural analyses of HIV drug resistance: 2. Examples of use and proof-of-concept

The HIV-PDI resource was designed and implemented to address the problems of drug resistance with a central focus on the 3D structure of the target-drug interaction. Clinical and biological data, structural and physico-chemical information and 3D interaction data concerning the targets (HIV protease) and the drugs (ARVs) were meticulously integrated and combined with tools dedicated to study HIV mutations and their consequences on the efficacy of drugs. Here, the capabilities of the HIV-PDI resource are demonstrated for several different scenarios ranging from retrieving information associated with patients to analyzing structural data relating cognate proteins and ligands. HIV-PDI allows such diverse data to be correlated, especially data linking antiretroviral drug (ARV) resistance to a given treatment with changes in three-dimensional interactions between a drug molecule and the mutated protease. Our work is based on the assumption that ARV resistance results from a loss of affinity between the mutated HIV protease and a drug molecule due to subtle changes in the nature of the protein-ligand interaction. Therefore, a set of patients whose resistance to first line treatment was corrected by a second line treatment was selected from the HIV-PDI database for detailed study, and several queries regarding these patients are processed via its graphical user interface. Considering the protease mutations found in the selected set of patients, our retrospective analysis was able to establish in most cases that the first line treatment was not suitable, and it predicted a second line treatment which agreed perfectly with the clincian’s prescription. The present study demonstrates the capabilities of HIV-PDI. We anticipate that this decision support tool will help clinicians and researchers find suitable HIV treatments for individual patients. The HIVPDI database is thereby useful as a system of data collection allowing interpretation on the basis of all available information, thus helping in possible decision-makings

HIV-PDI: A protein-drug interaction resource for structural analyses of HIV drug resistance: 1. Concepts and associated database

Overcoming the problem of resistance to antiretroviral drugs (ARVs) in HIV-infected patients is a major issue in AIDS research today. Advances in genome sequencing have facilitated the identification of a growing number of individual genotypes. Hence, it is now possible to understand HIV drug resistance at the molecular level by considering the three-dimensional (3D) structural interactions between ARVs and the mutated viral proteins of patients. Therefore, identification of the critical interactions lost further to one or several HIV mutations, and consequently the modifications of other molecular factors, could be indicators to propose appropriate ARVs escaping the resistance. This paper introduces the HIV-PDI (Protein-Drug Interactions) resource designed to be a decision making tool to propose alternative ARVs against a particular mutated viral protein, and thus to provide a personalized antiretroviral treatment. The HIV-PDI was conceived to serve as an integrated resource for studying HIV drug resistance at the structural level of the protein-drug interaction, with a special emphasis on the active site of the HIV drug target. As a first step, we focus on the well documented protease and related drugs. The HIV-PDI includes clinical information on patients, resistance to given ARVs treatments, HIV proteins structures and mutations, HIV protein/ARV drugs and their 3D interactions. The HIV-PDI may be queried using multiple combinations of fields including protein, drug and treatment conditions and coupled to visualization/analysis tools of 3D Protein-Drug interactions. The HIV-PDI resource can be used in order to help understand the appearance of resistance and to promote further novel drug and treatment developments based on analyses of 3D pattern of protein-drug interactions. A web-based version of HIV-PDI is available at http://hiv-pdi.loria.fr

Adenosine analogs bearing phosphate isosteres as human MDO1 ligands

Abstract The human O-acetyl-ADP-ribose deacetylase MDO1 is a mono-ADP-ribosylhydrolase involved in the reversal of post-translational modifications. Until now MDO1 has been poorly characterized, partly since no ligand is known besides adenosine nucleotides. Here, we synthesized thirteen compounds retaining the adenosine moiety and bearing bioisosteric replacements of the phosphate at the ribose 5′-oxygen. These compounds are composed of either a squaryldiamide or an amide group as the bioisosteric replacement and/or as a linker. To these groups a variety of substituents were attached such as phenyl, benzyl, pyridyl, carboxyl, hydroxy and tetrazolyl. Biochemical evaluation showed that two compounds, one from both series, inhibited ADP-ribosyl hydrolysis mediated by MDO1 in high concentrations