MAP kinase-interacting kinases (MNK1 and MNK2) are often activated downstream of ERK and p38 MAPK in the MAP kinase family. The role of MNKs in the development and progression of solid tumors and ...hematological malignancies has been widely discussed, particularly in the context of cap dependent translation, regulated by phosphorylation of eIF4E. MNK/eIF4E axis is involved in the expression of pro angiogenic, antiapoptotic, cell cycle, and motility proteins, such as MCL1, VEGF, MMP3, SNAIL, SMAD2, β-catenin or cyclin D1, and is essential during Ras and c Myc-induced transformation. MNK1/2 emerged as eligible targets for drug discovery in oncology, based on the antitumor effects observed in genetic knockout and RNA interference experiments and at the same time lack of adverse effects in dual knockout animals. There is a high interest in the development of pharmacological inhibitors of MNK1/2 as not only tools for further basic research studies but also potential drugs in diseases characterized by deregulated translation. Unfortunately, the role of MNK1/2 in cancer still remains elusive due to the absence of potent and selective probes. Moreover, in many instances, hypotheses have been built reliant upon unspecific MNK1/2 inhibitors such as CGP57380 or cercosporamide. Lately, the first two clinical programs targeting MNKs in oncology have been revealed (eFT508 and BAY 1143269), although several other MNK programs are currently running at the preclinical stage. This review aims to provide an overview of recent progress in the development of MNK inhibitors.
Cyclin-dependent kinase (CDK) inhibitors have been developed as potential anticancer therapeutics and several nonselective compounds are currently in advanced clinical trials. This review is focused ...on the key biological roles of CDK8 kinase, which provide a proof-of-principle for continued efforts toward effective cancer treatment, targeting activity of this CDK family member. Among currently identified kinase inhibitors, several displayed significant selectivity for CDK8 and notably the effectiveness in targeting cancer specific gene expression programs. Structural features of CDK8 and available ligands were discussed from a perspective of the rational drug design process. Current state of the art confirms that further development of CDK8 inhibitors will translate into targeted therapies in oncology. This article is part of a Special Issue entitled:Inhibitors of Protein Kinases.
•Impeded mRNA synthesis contributes to the effectiveness of pan-CDK inhibitors.•Numerous studies indicate that CDK8/cyclin C can function as a bona fide oncogene.•Oncogenic functions of CDK8 are related to the modulation of transcription programs.•Unique structure of CDK8/CycC among other CDKs enables SBDD of selective inhibitors.•First selective CDK8/cyclin C inhibitors are currently in preclinical development.
The ATPase RIG-I senses viral RNAs that contain 5′-triphosphates in the cytoplasm. It initiates a signaling cascade that activates innate immune response by interferon and cytokine production, ...providing essential antiviral protection for the host. The mode of RNA 5′-triphosphate sensing by RIG-I remains elusive. We show that the C-terminal regulatory domain RD of RIG-I binds viral RNA in a 5′-triphosphate-dependent manner and activates the RIG-I ATPase by RNA-dependent dimerization. The crystal structure of RD reveals a zinc-binding domain that is structurally related to GDP/GTP exchange factors of Rab-like GTPases. The zinc coordination site is essential for RIG-I signaling and is also conserved in MDA5 and LGP2, suggesting related RD domains in all three enzymes. Structure-guided mutagenesis identifies a positively charged groove as likely 5′-triphosphate-binding site of RIG-I. This groove is distinct in MDA5 and LGP2, raising the possibility that RD confers ligand specificity.
Background and Objective
The prediction of pharmacokinetic parameters for drugs metabolised by cytochrome P450 enzymes has been the subject of active research for many years, while the application of ...in vitro–in vivo extrapolation (IVIVE) techniques for non-cytochrome P450 enzymes has not been thoroughly evaluated. There is still no established quantitative method for predicting hepatic clearance of drugs metabolised by uridine 5′-diphospho-glucuronosyltransferases (UGTs), not to mention those which undergo hepatic uptake. The objective of the study was to predict the human hepatic clearance for telmisartan based on in vitro metabolic stability and hepatic uptake results.
Methods
Telmisartan was examined in liver systems, allowing to estimate intrinsic clearance (CL
int, in vitro
) based on the substrate disappearance rate with the use of liquid chromatography tandem mass spectrometry (LC-MS/MS) technique. Obtained CL
int, in vitro
values were corrected for corresponding unbound fractions. Prediction of human hepatic clearance was made from scaled unbound CL
int, in vitro
data with the use of the well-stirred model, and finally referenced to the literature value of observed clearance in humans, allowing determination of the essential scaling factors.
Results
The in vitro scaled CL
int, in vitro
by UGT1A3 was assessed using three systems, human hepatocytes, liver microsomes, and recombinant enzymes. Obtained values were scaled and hepatic metabolism clearance was predicted, resulting in significant clearance underprediction. Utilization of the extended clearance concept (ECC) and hepatic uptake improved prediction of hepatic metabolism clearance. The scaling factors for hepatocytes, assessing the in vitro–in vivo difference, changed from sixfold difference to only twofold difference with the application of the ECC.
Conclusions
The study showed that taking into consideration hepatic uptake of a drug allows us to obtain satisfactory scaling factors, hence enabling the prediction of in vivo hepatic glucuronidation from in vitro data.
Reed-Sternberg (RS) cells of classical Hodgkin lymphoma (cHL) express multiple immunoregulatory proteins that shape the cHL microenvironment and allow tumor cells to evade immune surveillance. ...Expression of certain immunoregulatory proteins is modulated by prosurvival transcription factors, such as NFκB and STATs. Because these factors also induce expression of the oncogenic PIM1/2/3 serine/threonine kinases, and as PIMs modulate transcriptional activity of NFκB and STATs, we hypothesized that these kinases support RS cell survival and foster their immune privilege. Here, we investigated PIM1/2/3 expression in cHL and assessed their role in developing RS cell immune privilege and survival. PIM1/2/3 were ubiquitously expressed in primary and cultured RS cells, and their expression was driven by JAK-STAT and NFκB activity. Genetic or chemical PIM inhibition with a newly developed pan-PIM inhibitor, SEL24-B489, induced RS cell apoptosis. PIM inhibition decreased cap-dependent protein translation, blocked JAK-STAT signaling, and markedly attenuated NFκB-dependent gene expression. In a cHL xenograft model, SEL24-B489 delayed tumor growth by 95.8% (P = .0002). Furthermore, SEL24-B489 decreased the expression of multiple molecules engaged in developing the immunosuppressive microenvironment, including galectin-1 and PD-L1/2. In coculture experiments, T cells incubated with SEL24-B489-treated RS cells exhibited higher expression of activation markers than T cells coincubated with control RS cells. Taken together, our data indicate that PIM kinases in cHL exhibit pleiotropic effects, orchestrating tumor immune escape and supporting RS cell survival. Inhibition of PIM kinases decreases RS cell viability and disrupts signaling circuits that link these cells with their niches. Thus, PIM kinases are promising therapeutic targets in cHL.
•PIM kinases are ubiquitously expressed in RS cells of cHL.•PIM inhibition decreases NFκB and STAT3/5 activity, cell viability, and expression of immunoregulatory proteins PD-L1/2 and galectin-1.
FASD Prevalence among Schoolchildren in Poland Okulicz‐Kozaryn, Katarzyna; Borkowska, Magdalena; Brzózka, Krzysztof
Journal of applied research in intellectual disabilities,
January 2017, Letnik:
30, Številka:
1
Journal Article
Recenzirano
Background
Prenatal Alcohol Exposure is a major cause of brain damage and developmental delay, known as Fetal Alcohol Spectrum Disorders (FASD) but in Poland is rarely diagnosed and the scale of ...problem is not known.
Methods
An active case ascertainment approach was applied to estimate the prevalence of FASD among 7–9 years olds. Pre‐screening was conducted in 113 randomly selected regular and special schools. In the screening phase participated 280 children (54% from the risk group, 60% boys). The entire number of eligible students (N = 2500) was taken as a denominator.
Results
The prevalence of FASD is not lower than 2%, including 0.4% of Fetal Alcohol Syndrome.
Conclusions
Neurodevelopmental disorders associated with PAE are a serious challenge for the public health system. Development of procedures and services to diagnose and to support individuals affected by PAE and their families is an urgent need in Poland.
In predictions about hepatic clearance (CL
), a number of studies explored the role of albumin and transporters in drug uptake by liver cells, challenging the traditional free-drug theory. It was ...proposed that liver uptake can occur for transporter substrate compounds not only from the drug's unbound form but also directly from the drug-albumin complex, a phenomenon known as uptake facilitated by albumin. In contrast to albumin, dextran does not exhibit binding properties for compounds. However, as a result of its inherent capacity for stabilization, it is widely used to mimic conditions within cells.
The uptake of eight known substrates of the organic anion-transporting polypeptide 1B3 (OATP1B3) was assessed using a human embryonic kidney cell line (HEK293), which stably overexpresses this transporter. An inert polymer, dextran, was used to simulate cellular conditions, and the results were compared with experiments involving human plasma and human serum albumin (HSA).
This study is the first to demonstrate that dextran increases compound uptake in cells with overexpression of the OATP1B3 transporter. Contrary to the common theory that highly protein-bound ligands interact with hepatocytes to increase drug uptake, the results indicate that dextran's interaction with test compounds does not significantly increase concentrations near the cell membrane surface.
We evaluated the effect of dextran on the uptake of known substrates using OATP1B3 overexpressed in the HEK293 cell line, and we suggest that its impact on drug concentrations in liver cells may differ from the traditional role of plasma proteins and albumin.
Inhibition of oncogenic transcriptional programs is a promising therapeutic strategy. A substituted tricyclic benzimidazole, SEL120-34A, is a novel inhibitor of Cyclin-dependent kinase 8 (CDK8), ...which regulates transcription by associating with the Mediator complex. X-ray crystallography has shown SEL120-34A to be a type I inhibitor forming halogen bonds with the protein's hinge region and hydrophobic complementarities within its front pocket. SEL120-34A inhibits phosphorylation of STAT1 S727 and STAT5 S726 in cancer cells in vitro. Consistently, regulation of STATs- and NUP98-HOXA9- dependent transcription has been observed as a dominant mechanism of action in vivo. Treatment with the compound resulted in a differential efficacy on AML cells with elevated STAT5 S726 levels and stem cell characteristics. In contrast, resistant cells were negative for activated STAT5 and revealed lineage commitment. In vivo efficacy in xenotransplanted AML models correlated with significant repression of STAT5 S726. Favorable pharmacokinetics, confirmed safety and in vivo efficacy provide a rationale for the further clinical development of SEL120-34A as a personalized therapeutic approach in AML.
Heme oxygenase-1 (HO-1, HMOX1) degrades pro-oxidant heme into carbon monoxide (CO), ferrous ions (Fe2+) and biliverdin. The enzyme exerts multiple cytoprotective functions associated with the ...promotion of angiogenesis and counteraction of the detrimental effects of cellular stress which are crucial for the survival of both normal and tumor cells. Accordingly, in many tumor types, high expression of HO-1 correlates with poor prognosis and resistance to treatment, i.e. chemotherapy, suggesting inhibition of HO-1 as a possible antitumor approach. At the same time, the lack of selective and well-profiled inhibitors of HO-1 determines the unmet need for new modulators of this enzyme, with the potential to be used in either adjuvant therapy or as the stand-alone targeted therapeutics.
In the current study, we provided novel inhibitors of HO-1 and validated the effect of pharmacological inhibition of HO activity by the imidazole-based inhibitor (SLV-11199) in human pancreatic (PANC-1) and prostate (DU-145) cancer cell lines. We demonstrated potent inhibition of HO activity in vitro and showed associated anticancer effectiveness of SLV-11199. Treatment with the tested compound led to decreased cancer cell viability and clonogenic potential. It has also sensitized the cancer cells to chemotherapy. In PANC-1 cells, diminished HO activity resulted in down-regulation of pro-angiogenic factors like IL-8. Mechanistic investigations revealed that the treatment with SLV-11199 decreased cell migration and inhibited MMP-1 and MMP-9 expression. Moreover, it affected mesenchymal phenotype by regulating key modulators of the epithelial to mesenchymal transition (EMT) signalling axis. Finally, F-actin cytoskeleton and focal contacts were destabilized by the reported compound.
Overall, the current study suggests a possible relevance of the tested novel inhibitor of HO activity as a potential anticancer compound. To support such utility, further investigation is still needed, especially in in vivo conditions.
•New small-molecules targeting the active site of HO-1 were designed and synthesized.•SLV-11199 is a potent inhibitor of HO activity.•Inhibition of HO activity can have anti-tumor effects.
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