Design, Synthesis, and Development of Pyrazolo[1,5-a]pyrimidine Derivatives as a Novel Series of Selective PI3Kδ Inhibitors: Part II-Benzimidazole Derivatives.

Phosphoinositide 3-kinase (PI3K) is the family of lipid kinases participating in vital cellular processes such as cell proliferation, growth, migration, or cytokines production. Due to the high expression of these proteins in many human cells and their involvement in metabolism regulation, normal embryogenesis, or maintaining glucose homeostasis, the inhibition of PI3K (especially the first class which contains four subunits: α, ß, γ, δ) is considered to be a promising therapeutic strategy for the treatment of inflammatory and autoimmune diseases such as systemic lupus erythematosus (SLE) or multiple sclerosis. In this work, we synthesized a library of benzimidazole derivatives of pyrazolo[1,5-a]pyrimidine representing a collection of new, potent, active, and selective inhibitors of PI3Kδ, displaying IC50 values ranging from 1.892 to 0.018 µM. Among all compounds obtained, CPL302415 (6) showed the highest activity (IC50 value of 18 nM for PI3Kδ), good selectivity (for PI3Kδ relative to other PI3K isoforms: PI3Kα/δ = 79; PI3Kß/δ = 1415; PI3Kγ/δ = 939), and promising physicochemical properties. As a lead compound synthesized on a relatively large scale, this structure is considered a potential future candidate for clinical trials in SLE treatment.

Design, Synthesis, and Development of pyrazolo[1,5-a]pyrimidine Derivatives as a Novel Series of Selective PI3Kδ Inhibitors: Part I-Indole Derivatives.

Phosphoinositide 3-kinase δ (PI3Kδ), a member of the class I PI3K family, is an essential signaling biomolecule that regulates the differentiation, proliferation, migration, and survival of immune cells. The overactivity of this protein causes cellular dysfunctions in many human disorders, for example, inflammatory and autoimmune diseases, including asthma or chronic obstructive pulmonary disease (COPD). In this work, we designed and synthesized a new library of small-molecule inhibitors based on indol-4-yl-pyrazolo[1,5-a]pyrimidine with IC50 values in the low nanomolar range and high selectivity against the PI3Kδ isoform. CPL302253 (54), the most potent compound of all the structures obtained, with IC50 = 2.8 nM, is a potential future candidate for clinical development as an inhaled drug to prevent asthma.

A novel JAK/ROCK inhibitor, CPL409116, demonstrates potent efficacy in the mouse model of systemic lupus erythematosus.

Systemic lupus erythematosus is a chronic inflammatory disease, in which treatment is still limited due to suboptimal efficacy and toxicities associated with the available therapies. JAK kinases are well known to play an important role in systemic lupus erythematous. There is growing evidence that ROCK kinases are also important in disease development. In this paper, we present the results of the development of CPL409116, a dual JAK and ROCK inhibitor. The studies we performed demonstrate that this molecule is an effective JAK and ROCK inhibitor which efficiently blocks disease progression in NZBWF1/J mouse models of systemic lupus erythematous.

Preclinical characterization of CPL302-253, a selective inhibitor of PI3Kδ, as the candidate for the inhalatory treatment and prevention of Asthma.

Asthma is a common chronic inflammatory disease. Although effective asthma therapies are available, part of asthmatic population do not respond to these treatment options. In this work we present the result of development of CPL302-253 molecule, a selective PI3Kδ inhibitor. This molecule is intended to be a preclinical candidate for dry powder inhalation in asthma treatment. Studies we performed showed that this molecule is safe and effective PI3Kδ inhibitor that can impact many immune functions. We developed a short, 15-day HDM induced asthma mouse model, in which we showed that CPL302-253 is able to block inflammatory processes leading to asthma development in vivo.

Activation of phosphoinositide 3-kinase delta by antipsychotic drugs: Preliminary results.

BACKGROUND: Catalytic subunit delta of phosphoinositide 3-kinase, p110δ, encoded by the PIK3CD gene, was recently proposed as a target for pharmacological treatment of schizophrenia. Current antipsychotic drugs were found to decrease the mRNA expression of PIK3CD, but the mechanism of this process is not known. The aim of the study was to elucidate the mechanism by which antipsychotic drugs affect the mRNA expression of PIK3CD. METHODS: The direct effect of haloperidol, clozapine, olanzapine, quetiapine and amisulpride on p110δ enzymatic activity was tested with a kinase assay, and the results were referenced against data on the mRNA expression of PIK3CD. RESULTS: Haloperidol, clozapine, olanzapine and quetiapine, but not amisulpride, at the concentration of 20-80 µM, were found to significantly increase enzymatic activity of p110δ by up to two times in a dose-dependent manner. Linear regression analysis revealed that more than 40% of the variance in antipsychotic drugs-induced changes in the expression of PIK3CD mRNA was explained only by changes in antipsychotic drug-regulated p110δ enzymatic activity (p = 0.011). CONCLUSIONS: Antipsychotic drugs differentially increase the enzymatic activity of p110δ. This effect is associated with that of mRNA expression of the PIK3CD gene. Drug-enzyme interaction may explain the effect of antipsychotic drugs on the expression of PIK3CD mRNA, however, further studies are needed to investigate this hypothesis.

Epithelial-mesenchymal transition confers resistance to selective FGFR inhibitors in SNU-16 gastric cancer cells.

BACKGROUND: Up to 10 % of primary gastric cancers are characterized by FGFR2 amplification, and fibroblast growth factor receptor (FGFR) inhibitors may represent therapeutic agents for patients with these malignancies. However, long-term benefits of the treatment might be limited owing to the occurrence of drug resistance. METHODS: To investigate the mechanisms of resistance to selective FGFR inhibitors, we established three FGFR2-amplified SNU-16 gastric cancer cell lines resistant to AZD4547, BGJ398, and PD173074, respectively. RESULTS: The resistant cell lines (SNU-16R) demonstrated changes characteristic of epithelial-to-mesenchymal transition (EMT). In addition, they displayed loss of expression of FGFR2 and other tyrosine kinase receptors concurrent with activation of downstream signaling proteins and upregulation of the transforming growth factor ß (TGF-ß) level. However, treatment of parental SNU-16 cells with TGF-ß1 did not evoke EMT, and pharmacological inhibition of TGF-ß receptor I was not sufficient to reverse EMT changes in the resistant cells. Finally, we showed that the SNU-16R cell lines were sensitive to the human epidermal growth factor receptor 2 inhibitor mubritinib and the heat shock protein 90 inhibitor AUY922. CONCLUSION: In conclusion, we provide experimental evidence that EMT-mediated resistance might emerge in gastric cancer patients following treatment with FGFR inhibitors, and mubritinib or AUY922 treatment may be an alternative therapeutic strategy for these patients.

Differences in gene expression and alterations in cell cycle of acute myeloid leukemia cell lines after treatment with JAK inhibitors.

Janus kinase (JAK) inhibitors are a promising treatment strategy in several hematological malignancies and autoimmune diseases. A number of inhibitors are in clinical development, and two have already reached the market. Unfortunately, all of them are burdened with different toxicity profiles. To check if the JAK inhibitors of different selectivity evoke different responses on JAK2-dependent and independent cells, we have used three acute myeloid leukemia cell lines with confirmed JAK2 mutation status. We have found that JAK inhibitors exert distinct effect on the expression of BCLXL, CCND1 and c-MYC genes, regulated by JAK pathway, in JAK2 wild type cells in comparison to JAK2 V617F-positive cell lines. Moreover, cell cycle analysis showed that inhibitors alter the cycle by arresting cells in different phases. Our results suggest that observed effect of JAK2 inhibitors on transcription and cell cycle level in different cell lines are associated not with activity within JAK family, but presumably with other off-target activities.

Cell-based assay for low- and high-scale screening of the Wnt/ß-catenin signaling modulators.

Deregulation of the Wnt/ß-catenin signaling pathway is associated with many serious disorders, including cancer and Alzheimer's disease. The pivotal player is ß-catenin, which avoids degradation after activation of the pathway and is translocated to the nucleus, where it interacts with TCF/LEF transcription factors and induces expression of genes involved in cell cycle and apoptosis regulation. The identification of small molecules that may affect Wnt/ß-catenin signaling remains an important target during the development of novel therapies. We used the TCF/LEF lentiviral vector and the Wnt-independent H1703 cell line to develop a luciferase reporter-based cell assay for screening of the Wnt/ß-catenin pathway modulators. Following the optimization of cell density, concentration of activator, and stimulation time, the reporter system was validated by demonstrating its specific and dose-dependent response to several established modulators of Wnt/ß-catenin signaling such as Wnt3a, small interfering RNA (siRNA) against ß-catenin, glycogen synthase kinase 3 (GSK-3), and ß-catenin/TCF transcription complex inhibitors. Two pilot screens of inhibitors and activators of Wnt/ß-catenin signaling identified potential novel modulators of this pathway. Our findings suggest that the H1703-7TFP assay constitutes a suitable model of low background and high sensitivity for the low- and high-scale screening of the Wnt/ß-catenin pathway modulators.

Lmo0171, a novel internalin-like protein, determines cell morphology of Listeria monocytogenes and its ability to invade human cell lines.

Internalins comprise a class of Listeria monocytogenes proteins responsible for activation of signalling pathways leading to phagocytic uptake of the bacterium by the host cell. In this paper, a possible role of Lmo0171-a new member of the internalin family was investigated. Disruption of the lmo0171 gene resulted in important cell morphology alterations along with a decrease in the ability to invade three eukaryotic cell lines, that is Int407, Hep-2 and HeLa and diminished adhesion efficiency to int407, thereby suggesting bifunctionality of the newly characterised Lmo0171 internalin.

Activating mutations in ALK kinase domain confer resistance to structurally unrelated ALK inhibitors in NPM-ALK-positive anaplastic large-cell lymphoma.

PURPOSE: Crizotinib, the first FDA-approved ALK inhibitor, showed significant antitumor activity in young patients with anaplastic large-cell lymphoma (ALCL) frequently displaying ALK rearrangement. However, long-term therapeutic benefits of crizotinib are limited due to development of drug resistance. CH5424802--more potent and selective ALK inhibitor--comprises a good candidate for second-line treatment in crizotinib-relapsed patients. The aim of this study was to determine possible mechanisms of resistance to ALK inhibitors that can appear in ALCL patients. METHODS: ALK+ ALCL cell lines resistant to crizotinib (Karpas299CR) and to CH5424802 (Karpas299CHR) were established by long-term exposure of Karpas299 cells to these inhibitors. Next, alterations in their sensitivity to ALK, HSP90 and mTOR inhibitors were investigated by cell viability and BrdU incorporation assays and immunoblot analysis. RESULTS: cDNA sequencing of ALK kinase domain revealed activating mutations-I1171T in Karpas299CR and F1174C in Karpas299CHR. The resistant cells displayed diminished sensitivity to structurally unrelated ALK inhibitors-crizotinib, CH5424802 and TAE684. Nevertheless, CH5424802 and TAE684 were still more potent against the resistant cells than crizotinib. Moreover, Karpas299CR and Karpas299CHR cells remained sensitive to HSP90 or mTOR inhibitors. CONCLUSIONS: Resistance mediated by activating mutations in ALK kinase domain may emerge in ALCL patients during ALK inhibitors treatment. However, more potent second-generation ALK inhibitors, HSP90 or mTOR inhibitors may represent an effective therapy for relapsed ALK+ ALCL patients.