Novel benzylidene-thiazolidine-2,4-diones inhibit Pim protein kinase activity and induce cell cycle arrest in leukemia and prostate cancer cells

Structure-Activity Relationship Study and Design Strategies of Hydantoin, Thiazolidinedione, and Rhodanine-Based Kinase Inhibitors: A Two-Decade Review

Cancer is one of the most prominent causes of the rapidly growing mortality numbers worldwide. Cancer originates from normal cells that have acquired the capability to alter their molecular, biochemical, and cellular traits. The alteration of cell signaling enzymes, such as kinases, can initiate and amplify cancer progression. As a curative method, the targeted therapy utilized small molecules' capability to inhibit kinase's cellular function. This review provides a brief history (1999-2023) of Small Molecule Kinase Inhibitors (SMKIs) discovery with their molecular perspective. Furthermore, this current review also addresses the application and the development of hydantoin, thiazolidinedione, and rhodanine-based derivatives as kinase inhibitors toward several subclasses (EGFR, PI3K, VEGFR, Pim, c-Met, CDK, IGFR, and ERK) accompanied by their structure-activity relationship study and their molecular interactions. The present work summarizes and compiles all the important structural information essential for developing hydantoin, thiazolidinedione, and rhodanine-based kinase inhibitors to improve their potency in the future.

Rhodanine-Based Chromophores: Fast Access to Capable Photoswitches and Application in Light-Induced Apoptosis

Molecular photoswitches are highly desirable in all chemistry-related areas of research. They provide effective outside control over geometric and electronic changes at the nanoscale using an easy to apply, waste-free stimulus. However, simple and effective access to such molecular tools is typically not granted, and elaborate syntheses and substitution schemes are needed in order to obtain efficient photoswitching properties. Here we present a series of rhodanine-based photoswitches that can be prepared in one simple synthetic step without requiring elaborate purification. Photoswitching is induced by UV and visible light in both switching directions, and thermal stabilities of the metastable states as well as quantum yields are very high. An additional benefit is the hydrogen-bonding capacity of the rhodanine fragment, which enables applications in supramolecular or medicinal chemistry. We further show that the known rhodanine-based inhibitor SMI-16a is a photoswitchable apoptosis inducer. The biological activity of SMI-16a can effectively be switched ON or OFF by reversible photoisomerization between the inactive E and the active Z isomer. Rhodanine-based photoswitches therefore represent an easy to access and highly valuable molecular toolbox for implementing light responsiveness to the breadth of functional molecular systems.

Recent Research Advances in Small-Molecule Pan-PIM Inhibitors

PIM kinase is consequently emerging as a promising target for cancer therapeutics and immunomodulation. PIM kinases are overexpressed in a variety of hematological malignancies and solid tumors, and their inhibition has become a strong therapeutic interest. Currently, some pan-PIM kinase inhibitors are being developed under different phases of clinical trials. Based on the different scaffold structures, they can be classified into various subclasses. The X-ray structure of the kinase complex outlines the rationale of hit compound confirmation in the early stage. Structure–activity relationships allow us to rationally explore chemical space and further optimize multiple physicochemical and biological properties. This review focuses on the discovery and development of small-molecule pan-PIM kinase inhibitors in the current research, and hopes to provide guidance for future exploration of the inhibitors.

Pim-1 kinase is a positive feedback regulator of the senescent lung fibroblast inflammatory secretome

Cellular senescence is emerging as a driver of idiopathic pulmonary fibrosis (IPF), a progressive and fatal disease with limited effective therapies. The senescence-associated secretory phenotype (SASP), involving the release of inflammatory cytokines and profibrotic growth factors by senescent cells, is thought to be a product of multiple cell types in IPF, including lung fibroblasts. NF-κB is a master regulator of the SASP, and its activity depends on the phosphorylation of p65/RelA. The purpose of this study was to assess the role of Pim-1 kinase as a driver of NF-κB-induced production of inflammatory cytokines from low-passage IPF fibroblast cultures displaying markers of senescence. Our results demonstrate that Pim-1 kinase phosphorylates p65/RelA, activating NF-κB activity and enhancing IL-6 production, which in turn amplifies the expression of PIM1, generating a positive feedback loop. In addition, targeting Pim-1 kinase with a small molecule inhibitor dramatically inhibited the expression of a broad array of cytokines and chemokines in IPF-derived fibroblasts. Furthermore, we provide evidence that Pim-1 overexpression in low-passage human lung fibroblasts is sufficient to drive premature senescence, in vitro. These findings highlight the therapeutic potential of targeting Pim-1 kinase to reprogram the secretome of senescent fibroblasts and halt IPF progression.

Green Synthesis of Thiazolidine-2,4-dione Derivatives and Their Lipoxygenase Inhibition Activity With QSAR and Molecular Docking Studies

Thiazolidinediones are five-membered, heterocyclic compounds that possess a number of pharmacological activities such as antihyperglycemic, antitumor, antiarthritic, anti-inflammatory, and antimicrobial. Conventional methods for their synthesis are often environmentally unacceptable due to the utilization of various catalysts and organic solvents. In this study, deep eutectic solvents were used in the synthesis of thiazolidinedione derivatives that acted as both solvents and catalysts. Initially, a screening of 20 choline chloride-based deep eutectic solvents for thiazolidinedione synthesis, via Knoevenagel condensation, was performed in order to find the most suitable solvent. Deep eutectic solvent, choline chloride, N-methylurea, was proven to be the best for further synthesis of 19 thiazolidinedione derivatives. Synthesized thiazolidinediones are obtained in yields from 21.49% to 90.90%. The synthesized compounds were tested for the inhibition of lipid peroxidation as well as for the inhibition of soy lipoxygenase enzyme activity. The antioxidant activity of the compounds was also determined by the ABTS and DPPH methods. Compounds showed lipoxygenase inhibition in the range from 7.7% to 76.3%. Quantitative structure–activity relationship model (R2 = 0.88; Q2loo = 0.77; F = 33.69) for the inhibition of soybean lipoxygenase was obtained with descriptors Mor29m, G2u, and MAXDP. The molecular docking confirms experimentally obtained results, finding the binding affinity and interactions with the active sites of soybean LOX-3.

2-Thioxothiazolidin-4-one Analogs as Pan-PIM Kinase Inhibitors

Proviral integration site for Moloney murine leukemia virus (PIM) kinases are proto-oncogenic kinases involved in the regulation of several cellular processes. PIM kinases are promising targets for new drug development because they play a major role in many cancer-specific pathways, such as survival, apoptosis, proliferation, cell cycle regulation, and migration. Here, 2-thioxothiazolidin-4-one derivatives were synthesized and evaluated as potent pan-PIM kinase inhibitors. Optimized compounds showed single-digit nanomolar IC₅₀ values against all three PIM kinases with high selectivity over 14 other kinases. Compound 17 inhibited the growth of Molm-16 cell lines (EC₅₀ = 14 nM) and modulated the expression of pBAD and p4EBP1 in a dose-dependent manner.

Dual Inhibition of AKT and MEK Pathways Potentiates the Anti-Cancer Effect of Gefitinib in Triple-Negative Breast Cancer Cells

There is an unmet medical need for the development of new targeted therapeutic strategies for triple-negative breast cancer (TNBC). With drug combination screenings, we found that the triple combination of the protein kinase inhibitors (PKIs) of the epidermal growth factor receptor (EGFR), v-akt murine thymoma viral oncogene homolog (AKT), and MAPK/ERK kinase (MEK) is effective in inducing apoptosis in TNBC cells. A set of PKIs were first screened in combination with gefitinib in the TNBC cell line, MDA-MB-231. The AKT inhibitor, AT7867, was identified and further analyzed in two mesenchymal stem-like (MSL) subtype TNBC cells, MDA-MB-231 and HS578T. A combination of gefitinib and AT7867 reduced the proliferation and long-term survival of MSL TNBC cells. However, gefitinib and AT7867 induced the activation of the rat sarcoma (RAS)/ v-raf-1 murine leukemia viral oncogene homolog (RAF)/MEK/ extracellular signal-regulated kinase (ERK) pathway. To inhibit this pathway, MEK/ERK inhibitors were further screened in MDA-MB-231 cells in the presence of gefitinib and AT7867. As a result, we identified that the MEK inhibitor, PD-0325901, further enhanced the anti-proliferative and anti-clonogenic effects of gefitinib and AT7867 by inducing apoptosis. Our results suggest that the dual inhibition of the AKT and MEK pathways is a novel potential therapeutic strategy for targeting EGFR in TNBC cells.

A serine/threonine protein PIM kinase as a biomarker of cancer and a target for anti-tumor therapy

The PIM Kinases belong to the family of a proto-oncogene that essentially phosphorylates the serine/threonine residues of the target proteins. They are primarily categorized into three types PIM-1, PIM-2, PIM-3 which plays an indispensable regulatory role in signal transduction cascades, by promoting cell survival, proliferation, and drug resistance. These kinases are overexpressed in several solid as well as hematopoietic tumors which supports in vitro and in vivo malignant cell growth along with survival by regulating cell cycle and inhibiting apoptosis. They lack regulatory domain which makes them constitutively active once transcribed. PIM kinases usually appear to be important downstream effectors of oncoproteins which overexpresses and helps in mediating drug resistance to available agents, such as rapamycin. Structural studies of PIM kinases revealed that they have unique hinge regions where two Proline resides and makes ATP binding unique, by offering a target for an increasing number of potent PIM kinase inhibitors. Preclinical studies of those inhibitory compounds in various cancers indicate that these novel agents show promising activity and some of them currently being under examination. In this review, we have outlined PIM kinases molecular mechanism and signaling pathways along with matriculation in various cancer and list of inhibitors often used.

s-Proline Covalented Silicapropyl Modified Magnetic Nanoparticles: Synthesis, Characterization, Biological and Catalytic Activity for the Synthesis of thiazolidin-4- ones

BACKGROUND

Thiazolidinoneones are important pharmaceutical compounds because of their biological activities. Several methods for the synthesis of 4-thiazolidinones are widely reported in the literature. The main synthetic routes to synthesize 1,3-thiazolidin-4-ones involve three components reaction between amine, a carbonyl compound and thioglycolic acid.

OBJECTIVE

s-Proline covalented silicapropyl modified magnetic nanoparticles (Fe3O4@SiO2-Pr @s-proline) were prepared. The antibacterial activity of synthesized nanoparticles against four bacterias was investigated that showed that 30 Mg/L of synthesized nanoparticles is a suitable concentration for bacterial inhibitory. Finally, the catalytic application of the synthesized s-Proline covalented silicapropyl modified magnetic nanoparticles for the synthesis of thiazolidinones and pyrazolyl thiazolidinones under stirring in aqueous media was evaluated. All of the synthesized organic compounds were characterized by mp, FT IR, 1H NMR, 13C NMR and elemental analysis.

MATERIALS AND METHODS

A combination of aldehyde (1.0 mmol), thioglycolic acid (1.0 mmol), various amines (1mmol) and 0.05 g Fe3O4@SiO2propyl@L-proline, were reacted at room temperature under stirring in 10 mL water. After completion of the reaction, as indicated by TLC (4:1 hexane: ethylacetate), the reaction mixture was filtered in the presence of an effective magnetic bar to separate the nanocatalyst. The nanocatalyst was washed with a mixture of hot EtOH: H2O two times. The crude products were collected and recrystallized from ethanol, if necessary.

RESULTS AND DISCUSSION

We present a novel avenue for the synthesis of thiazolidinones in the presence of Fe3O4@SiO2-Pr @s-proline under solvent-free conditions.

CONCLUSION

In conclusion, we have synthesized Fe3O4@SiO2-Pr@s-proline nanoparticles. Their biological activity against 4 bacterias was investigated. It released that 30Mg/L is the suitable concentration of synthesized nanoparticle for bacterial inhibitory. The catalytic efficiency of the catalyst was checked in the multicomponent reaction of various aldehyde, thioglycolic acid and various amines under stirring. This nanoparticle is a new organic-inorganic hybrid nanoparticle. The operational simplicity, the excellent yields of products, ease of separation and recyclability of the magnetic catalyst, waste reduction and high selectivity are the main advantages of this catalytic method. Furthermore, this new avenue is inexpensive and environmentally benign.

Urazolium diacetate as a new, efficient and reusable Brønsted acid ionic liquid for the synthesis of novel derivatives of thiazolidine-4-ones

Urazolium diacetate catalyzed synthesis of new derivatives of 1,3-thiazolidine-4-ones (azo dispersive dyes family)viamulticomponent reaction of various aldehydes, thioglycolic acid and 4-aminoazobenzene under solvent-free reaction was reported.

Current perspectives on targeting PIM kinases to overcome mechanisms of drug resistance and immune evasion in cancer

PIM kinases are a class of serine/threonine kinases that play a role in several of the hallmarks of cancer including cell cycle progression, metabolism, inflammation and immune evasion. Their constitutively active nature and unique catalytic structure has led them to be an attractive anticancer target through the use of small molecule inhibitors. This review highlights the enhanced activity of PIM kinases in cancer that can be driven by hypoxia in the tumour microenvironment and the important role that aberrant PIM kinase activity plays in resistance mechanisms to chemotherapy, radiotherapy, anti-angiogenic therapies and targeted therapies. We highlight an interaction of PIM kinases with numerous major oncogenic players, including but not limited to, stabilisation of p53, synergism with c-Myc, and notable parallel signalling with PI3K/Akt. We provide a comprehensive overview of PIM kinase's role as an escape mechanism to targeted therapies including PI3K/mTOR inhibitors, MET inhibitors, anti-HER2/EGFR treatments and the immunosuppressant rapamycin, providing a rationale for co-targeting treatment strategies for a more durable patient response. The current status of PIM kinase inhibitors and their use as a combination therapy with other targeted agents, in addition to the development of novel multi-molecularly targeted single therapeutic agents containing a PIM kinase targeting moiety are discussed.

Interaction of thiourea and urea with maleimide: comparative theoretical DFT study

A gas-phase mechanism reaction of maleimide with urea or thiourea was studied by DFT method. A comparison between atomic charges, Fukui index evaluation and Frontier orbitals theory was carried out. The involvement of pre- and post-reactive complexes was examined as the reaction profiles are modelled. For each mechanism, two approaches have been proposed through nitrogen and sulfur (for thiourea), or oxygen and nitrogen (for urea) attack. The results indicate that the carbon double bonded of maleimide is the electophilic site and chalcogen atom of chalcogenourea is the nucleophilic one. The obtained activation free energies predict suitable specie that could be generated after an opening-cycle and new bonds formation. Consequently, the sulfur attack of thiourea was promoted on oxygen (urea) which is in accordance with the experiments.

Development of a Novel Series of Anticancer and Antidiabetic: Spirothiazolidines Analogs

4-(4-Aminophenyl)-1-thia-4-azaspiro[4.5]decan-3-one 1 was prepared and allowed to react with nitrogen nucleophiles to give the corresponding hydrazones 2–4. Further, compound 1 underwent diazotization and afforded the parallel hydrazono derivative 5; moreover, compound 1 refluxed with active methylene derivatives yielded the corresponding aminospirothiazolo pyridine–carbonitrile derivative 6 and spirothiazolopyridinone–carbonitrile derivative 7. Condensation of spirothiazolidine 1 with 4-chlorobenzaldehyde gave the corresponding spiro arylidiene derivative 8, which was utilized as a component of Micheal addition to react with excess of nitrogen nucleophiles to yield novel ring frameworks 4-(3′-(4-chlorophenyl)–spiro [cyclohexane-1,5′-pyrazolo[3,4-d]thiazol]-6′(1′H)-yl)aniline (9) and 4-(3′-(4-chlorophenyl)-6′H- spiro[cyclohexane-1,5′-thiazolo[5,4-d]isoxazol]-6′-yl)aniline (10). Finally, when spirothiazolo pyridinone–carbonitrile derivative 7 sodium salt generated in situ was reacted with different alkyl halides, it produced the corresponding N-derivatives 12–16. Three compounds, 6, 14, and 16, showed high significantly anticancer activities compared with Doxorubicin® (positive control) against human breast carcinoma (MCF-7) and human liver carcinoma (HepG-2) cell lines. On the other hand, compounds 6 and 9 showed higher therapeutic indices for both of alpha-amylase inhibitor and alpha-glucosidase inhibitor than the other tested compounds compared with the antidiabetic Acarbose (positive control).

PIM kinase inhibitor, AZD1208, inhibits protein translation and induces autophagy in primary chronic lymphocytic leukemia cells

The PIM1, PIM2, and PIM3 serine/threonine kinases play a role in the proliferation and survival of cancer cells. Mice lacking these three kinases were viable. Further, in human hematological malignancies, these proteins are overexpressed making them suitable targets. Several small molecule inhibitors against this enzyme were synthesized and tested. AZD1208, an orally available small-molecule drug, inhibits all three PIM kinases at a low nanomolar range. AZD1208 has been tested in clinical trials for patients with solid tumors and hematological malignancies, especially acute myelogenous leukemia. The present study evaluated the efficacy and biological actions of AZD1208 in chronic lymphocytic leukemia (CLL) cells. CLL cells had higher levels of PIM2 protein and mRNAs than did normal lymphocytes from healthy donors. Treatment of CLL lymphocytes with AZD1208 resulted in modest cell death, whereas practically no cytotoxicity was observed in healthy lymphocytes. To determine the mechanism by which AZD1208 inhibits PIM kinase function, we evaluated PIM kinase pathway and downstream substrates. Because peripheral blood CLL cells are replicationally quiescent, we analyzed substrates involved in apoptosis, transcription, and translation but not cell cycle targets. AZD1208 inhibited protein translation by decreasing phosphorylation levels of 4E-binding protein 1 (4E-BP1). AZD1208 induced autophagy in replicationally-quiescent CLL cells, which is consistent with protein translation inhibition. These data suggest that AZD1208 may elicit cytotoxicity in CLL cells through inhibiting translation and autophagy induction.

PIM-2 protein kinase negatively regulates T cell responses in transplantation and tumor immunity

PIM kinase family members play a crucial role in promoting cell survival and proliferation via phosphorylation of their target substrates. In this study, we investigated the role of the PIM kinases with respect to T cell responses in transplantation and tumor immunity. We found that the PIM-2 isoform negatively regulated T cell responses to alloantigen, in contrast to the PIM-1 and PIM-3 isoforms, which acted as positive regulators. T cells deficient in PIM-2 demonstrated increased T cell differentiation toward Th1 subset, proliferation, and migration to target organs after allogeneic bone marrow transplantation, resulting in dramatically accelerated graft-versus-host disease (GVHD) severity. Restoration of PIM-2 expression markedly attenuated the pathogenicity of PIM-2-deficient T cells to induce GVHD. On the other hand, mice deficient in PIM-2 readily rejected syngeneic tumor, which was primarily dependent on CD8+ T cells. Furthermore, silencing PIM-2 in polyclonal or antigen-specific CD8+ T cells substantially enhanced their antitumor response in adoptive T cell immunotherapy. We conclude that PIM-2 kinase plays a prominent role in suppressing T cell responses, and provide a strong rationale to target PIM-2 for cancer immunotherapy.

Targeting the PIM protein kinases for the treatment of a T-cell acute lymphoblastic leukemia subset

New approaches are needed for the treatment of patients with T-cell acute lymphoblastic leukemia (T-ALL) who fail to achieve remission with chemotherapy. Analysis of the effects of pan-PIM protein kinase inhibitors on human T-ALL cell lines demonstrated that the sensitive cell lines expressed higher PIM1 protein kinase levels, whereas T-ALL cell lines with NOTCH mutations tended to have lower levels of PIM1 kinase and were insensitive to these inhibitors. NOTCH-mutant cells selected for resistance to gamma secretase inhibitors developed elevated PIM1 kinase levels and increased sensitivity to PIM inhibitors. Gene profiling using a publically available T-ALL dataset demonstrated overexpression of PIM1 in the majority of early T-cell precursor (ETP)-ALLs and a small subset of non-ETP ALL. While the PIM inhibitors blocked growth, they also stimulated ERK and STAT5 phosphorylation, demonstrating that activation of additional signaling pathways occurs with PIM inhibitor treatment. To block these pathways, Ponatinib, a broadly active tyrosine kinase inhibitor (TKI) used to treat chronic myelogenous leukemia, was added to this PIM-inhibitor regimen. The combination of Ponatinib with a PIM inhibitor resulted in synergistic T-ALL growth inhibition and marked apoptotic cell death. Treatment of mice engrafted with human T-ALL with these two agents significantly decreased the tumor burden and improved the survival of treated mice. This dual therapy has the potential to be developed as a novel approach to treat T-ALL with high PIM expression.

Highly Selective Red-Emitting Fluorescent Probe for Imaging Cancer Cells in Situ by Targeting Pim-1 Kinase

Based on the fact that enzyme-targeting probes are highly sensitive and selective, a novel red-emitting probe (NB-BF) for Pim-1 kinase including three parts, fluorophore (NB), linker, and inhibitor (BF), has been designed for cancer optical imaging. In its free state, NB-BF is folded and the fluorescence quenched by PET between fluorophore and inhibitor both in PBS buffer and in normal cells. Significantly, it emitted strong red fluorescence in Pim-1 overexpressed cancer cells. The specificity of NB-BF for Pim-1 kinase was directly demonstrated by gene silencing analysis. Furthermore, it is the first time to know where Pim-1 kinase mainly distributes at mitochondria with Pearson's correlation factor (R_r) of 0.965 and to provide a fluorescent tool to verify the function of the Pim-1 kinase. More importantly, NB-BF was applied in tissue imaging and preferentially labeled tumors in vivo.

High glucose promotes vascular smooth muscle cell proliferation by upregulating proto-oncogene serine/threonine-protein kinase Pim-1 expression

Serine/threonine kinase proviral integration site for Moloney murine leukemia virus 1 (Pim-1) plays an essential role in arterial wall cell proliferation and associated vascular diseases, including pulmonary arterial hypertension and aortic wall neointima formation. Here we tested a role of Pim-1 in high-glucose (HG)-mediated vascular smooth muscle cell (VSMC) proliferation. Pim-1 and proliferating cell nuclear antigen (PCNA) expression levels in arterial samples from streptozotocin-induced hyperglycemia rats were increased, compared with their weak expression in normoglycemic groups. In cultured rat VSMCs, HG led to transient Pim-1 expression decline, followed by sustained expression increase at both transcriptional and translational levels. Immunoblot analysis demonstrated that HG increased the expression of the 33-kDa isoform of Pim-1, but at much less extent to its 44-kDa plasma membrane isoform. D-glucose at a concentration of 25 mmol/L showed highest activity in stimulating Pim-1 expression. Both Pim-1 inhibitor quercetagetin and STAT3 inhibitor stattic significantly attenuated HG-induced VSMC proliferation and arrested cell cycle progression at the G1 phase. Quercetagetin showed no effect on Pim-1 expression but decreased the phosphorylated-Bad (T112)/Bad ratio in HG-treated VSMCs. However, stattic decreased phosphorylated-STAT3 (Y705) levels and caused transcriptional and translational down-regulation of Pim-1 in HG-treated VSMCs. Our findings suggest HG-mediated Pim-1 expression contributes to VSMC proliferation, which may be partly due to the activation of STAT3/Pim-1 signaling.

Design, synthesis and biological evaluation of some novel sulfonamide derivatives as apoptosis inducers

Several novel thiazolidinone and fused thiazolidinone derivatives bearing benzenesulfonamide moiety were synthesized and confirmed via spectral and elemental analyses. The newly synthesized compounds were evaluated for their cytotoxic activity on colorectal cancer cell line (Caco-2). All the synthesized compounds showed better activity than the reference standards (Doxorubicin and 5-FU). Investigation of the apoptotic activity of the most active compounds revealed that compounds 3a, 5a, 5c and 6c activate both caspase-3 and Fas-ligand in Caco-2 cell line. Compound 3a was the most active compound with caspase-3 concentration of 0.43 nmol/mL and Fas-ligand concentration of 775.2 pg/mL in treated Caco-2 cells. Compound 3a was radiolabeled with ^99mTc and its biodistribution pattern was evaluated in vivo using normal Swiss Albino mice. ^99mTc-compound 3a complex didn't exhibit any accumulation in any body organs except for its accumulation in the colon; target organ; where it showed 8.97 ± 1.35 %ID/g at 15min p. i. that elevated till 16.02 ± 2.43 %ID/g at 120min p. i.

First Bispecific Inhibitors of the Epidermal Growth Factor Receptor Kinase and the NF-κB Activity As Novel Anticancer Agents

The activation of the NF-κB transcription factor is a major adaptive response induced upon treatment with EGFR kinase inhibitors, leading to the emergence of resistance in nonsmall cell lung cancer and other tumor types. To suppress this survival mechanism, we developed new thiourea quinazoline derivatives that are dual inhibitors of both EGFR kinase and the NF-κB activity. Optimization of the hit compound, identified in a NF-κB reporter gene assay, led to compound 9b, exhibiting a cellular IC₅₀ for NF-κB inhibition of 0.3 μM while retaining a potent EGFR kinase inhibition (IC₅₀ = 60 nM). The dual inhibitors showed a higher potency than gefitinib to inhibit cell growth of EGFR-overexpressing tumor cell lines in vitro and in a xenograft model in vivo, while no signs of toxicity were observed. An investigation of the molecular mechanism of NF-κB suppression revealed that the dual inhibitors depleted the transcriptional coactivator CREB-binding protein from the NF-κB complex in the nucleus.

Upregulation of PIM2 by Underexpression of MicroRNA-135-5p Improves Survival Rates of Skin Allografts by Suppressing Apoptosis of Fibroblast Cells

BACKGROUND It has been reported that miR-135-5p is involved with many diseases. In this study, we aimed at define the relationship between miR-135-5p level and burn patient survival after skin transplantation. MATERIAL AND METHODS Expression of miR-135-5p and PIM2 was measured using real-time PCR and Western blot analysis in the skin samples collected from burn patients who received skin graft or in the fibroblast cells transfected with miR-135-5p mimics or inhibitors. The regulatory association between miR-135-5p and PIM2 was verified using bioinformatics analysis and luciferase assay. RESULTS The expression level of miR-135-5p was determined in 60 tissue samples divided into 2 groups based on the presence of rejection (long survival n=30, and short survival n=30). We found that miR-135-5p was substantially downregulated in the long survival group. We then searched the miRNA database online with the "seed sequence" located within the 3'-UTR of the target gene, and then validated PIM2 to be the direct gene via luciferase reporter assay system. We also established the negative regulatory relationship between miR-135-5p and PIM2 via studying the relative luciferase activity. We also conducted real-time PCR and Western blot analysis to study the mRNA and protein expression level of PIM2 among different groups (long survival n=30, short survival n=30) or cells treated with scramble control, miR-135-5p mimics, PIM2 siRNA, and miR-135-5p inhibitors, indicating the negative regulatory relationship between MiR-135-5p and PIM2. We also conducted experiments to investigate the influence of miR-135-5p and PIM2 on viability and apoptosis of cells. The results showed miR-135-5p reduced the viability of cells, while PIM2 negatively interfered with the viability of cells, and miR-135-5p inhibited apoptosis and PIM2 suppressed apoptosis. CONCLUSIONS MiR-135-5p is involved with the prognosis of burn patients after skin transplantation. PIM2 is a virtual target of miR-135-5p, and there is a negative regulatory relationship between miR-135-5p and PIM2. MiR-135-5p and PIM2 interfered with the viability and apoptosis in cells.

Protein profiling identifies mTOR pathway modulation and cytostatic effects of Pim kinase inhibitor, AZD1208, in acute myeloid leukemia

Pim kinases phosphorylate and regulate a number of key acute myeloid leukemia (AML) cell survival proteins, and Pim inhibitors have recently entered clinical trial for hematological malignancies. AZD1208 is a small molecule pan-Pim kinase inhibitor and AZD1208 treatment resulted in growth inhibition and cell size reduction in AML cell lines including FLT3-WT (OCI-AML-3, KG-1a, and MOLM-16) and FLT3-ITD mutated (MOLM-13 and MV-4-11). There was limited apoptosis induction (<10% increase) in the AML cell lines evaluated with up to 3 μM AZD1208 for 24 h, suggesting that growth inhibition is not through apoptosis induction. Using reverse phase protein array (RPPA) and immunoblot analysis, we identified that AZD1208 resulted in suppression of mTOR signaling, including inhibition of protein phosphorylation of mTOR (Ser2448), p70S6K (Thr389), S6 (Ser235/236), and 4E-BP1 (Ser65). Consistent with mTOR inhibition, there was also a reduction in protein synthesis that correlated with cell size reduction and growth inhibition with AZD1208; our study provides insights into the mechanism of AZD1208.

A facile synthesis and antimicrobial activity evaluation of sydnonyl-substituted thiazolidine derivatives

Some new sydnonyl-substituted thiazolidine derivatives were synthesized in high yields by the modified Knoevenagel condensation of 3-aryl-4-formylsydnones with thiazolidine-2,4-dione and 2-thioxo-thiazolidine-4-one, respectively. All the synthesized thiazolidine derivatives were screened by paper-disc method to identify their antimicrobial activities against three bacteria viz. Staphylococcus aureus, Proteus vulgaris and Escherichia coli, and two fungal cultures viz. Aspergillus niger and Penicillium citrinum. The reference drugs were Norfloxacin and Griseofulvin, respectively. The screening data indicated that the tested sydnonyl-substituted thiazolidine derivatives exhibited no obvious antibacterial activity compared with the standard drug Norfloxacin. However, thiazolidine derivatives displayed significant antifungal activities against Penicillium citrinum and Aspergillus niger. Notably, all of the tested compounds showed growth inhibitory activity 1.5-4.4 times higher than that of the standard drug Griseofulvin against the two fungi.

Pim kinases in hematological malignancies: where are we now and where are we going?

The proviral insertion in murine (PIM) lymphoma proteins are a serine/threonine kinase family composed of three isoformes: Pim-1, Pim-2 and Pim-3. They play a critical role in the control of cell proliferation, survival, homing and migration. Recently, overexpression of Pim kinases has been reported in human tumors, mainly in hematologic malignancies. In vitro and in vivo studies have confirmed their oncogenic potential. Indeed, PIM kinases have shown to be involved in tumorgenesis, to enhance tumor growth and to induce chemo-resistance, which is why they have become an attractive therapeutic target for cancer therapy. Novel molecules inhibiting Pim kinases have been evaluated in preclinical studies, demonstrating to be effective and with a favorable toxicity profile. Given the promising results, some of these compounds are currently under investigation in clinical trials. Herein, we provide an overview of the biological activity of PIM-kinases, their role in hematologic malignancies and future therapeutic opportunities.

A small-molecule inhibitor of PIM kinases as a potential treatment for urothelial carcinomas

The proto-oncogene proviral integration site for moloney murine leukemia virus (PIM) kinases (PIM-1, PIM-2, and PIM-3) are serine/threonine kinases that are involved in a number of signaling pathways important to cancer cells. PIM kinases act in downstream effector functions as inhibitors of apoptosis and as positive regulators of G₁-S phase progression through the cell cycle. PIM kinases are upregulated in multiple cancer indications, including lymphoma, leukemia, multiple myeloma, and prostate, gastric, and head and neck cancers. Overexpression of one or more PIM family members in patient tumors frequently correlates with poor prognosis. The aim of this investigation was to evaluate PIM expression in low- and high-grade urothelial carcinoma and to assess the role PIM function in disease progression and their potential to serve as molecular targets for therapy. One hundred thirty-seven cases of urothelial carcinoma were included in this study of surgical biopsy and resection specimens. High levels of expression of all three PIM family members were observed in both noninvasive and invasive urothelial carcinomas. The second-generation PIM inhibitor, TP-3654, displays submicromolar activity in pharmacodynamic biomarker modulation, cell proliferation studies, and colony formation assays using the UM-UC-3 bladder cancer cell line. TP-3654 displays favorable human ether-à-go-go-related gene and cytochrome P450 inhibition profiles compared with the first-generation PIM inhibitor, SGI-1776, and exhibits oral bioavailability. In vivo xenograft studies using a bladder cancer cell line show that PIM kinase inhibition can reduce tumor growth, suggesting that PIM kinase inhibitors may be active in human urothelial carcinomas.

The Pim-1 protein kinase is an important regulator of MET receptor tyrosine kinase levels and signaling

MET, the receptor for hepatocyte growth factor (HGF), plays an important role in signaling normal and tumor cell migration and invasion. Here, we describe a previously unrecognized mechanism that promotes MET expression in multiple tumor cell types. The levels of the Pim-1 protein kinase show a positive correlation with the levels of MET protein in human tumor cell lines and patient-derived tumor materials. Using small interfering RNA (siRNA), Pim knockout mice, small-molecule inhibitors, and overexpression of Pim-1, we confirmed this correlation and found that Pim-1 kinase activity regulates HGF-induced tumor cell migration, invasion, and cell scattering. The novel biochemical mechanism for these effects involves the ability of Pim-1 to control the translation of MET by regulating the phosphorylation of eukaryotic initiation factor 4B (eIF4B) on S406. This targeted phosphorylation is required for the binding of eIF4B to the eIF3 translation initiation complex. Importantly, Pim-1 action was validated by the evaluation of patient blood and bone marrow from a phase I clinical trial of a Pim kinase inhibitor, AZD1208. These results suggest that Pim inhibitors may have an important role in the treatment of patients where MET is driving tumor biology.

Pim kinase inhibitory and antiproliferative activity of a novel series of meridianin C derivatives

A novel series of meridianin C derivatives substituted at C-5 position were prepared. These derivatives were tested for their kinase inhibitory potencies against all three family members of the pim kinases (Pim-1, Pim-2 and Pim-3). In addition, their antiproliferative activity towards three human leukemia cell lines as MV4-11, Jurkat clone E6-1 and K562 has been evaluated. Structure activity relationships at C-3 and C-5 positions of indole were performed to better understand the mechanism behind the enhanced potency. Compound 7f, the most active compound of the series showed a single-digit nanomolar IC50 with selectivity towards Pim-1 kinase.

Small molecule inhibitors of PIM1 kinase: July 2009 to February 2013 patent update

INTRODUCTION

The proviral insertion in murine (PIM) lymphoma proteins for which three isoforms, PIM1, PIM2 and PIM3 have been identified, belonging to the family of serine/threonine kinases has emerged recently as an important therapeutic target for the development of selective inhibitors as the new drugs for treating hematological malignancies and solid tumors. The small molecules developed by academia and the pharmaceutical industry have steadily increased in the last few years. Several drug discovery groups focus on treating disorders, such as cancer mediated by PIM kinase, have provided preclinical evidence suggesting that PIM inhibitor provides anti-apoptotic activity, inhibit cell survival and cell proliferation.

AREAS COVERED

This article discloses recent reviews on research and advances published in the patent literature and scientific publications from July 2009 to February 2013, highlighting discoveries on PIM1 kinase.

EXPERT OPINION

Several PIM1 kinase small molecule inhibitors are now at the pre-clinical research stage, development and testing. Though nearly 40 patents emerged in the last 3 years, greater efforts towards additional designs and medicinal chemistry continues for developing clinically efficacious PIM1 inhibitors, due to the significance of the target for cancer and the potential for novel and diverse inhibitors as drug candidates.

Discovery and optimization of pyrrolo[1,2-a]pyrazinones leads to novel and selective inhibitors of PIM kinases

A novel series of PIM inhibitors was derived from a combined effort in natural product-inspired library generation and screening. The novel pyrrolo[1,2-a]pyrazinones initial hits are inhibitors of PIM isoforms with IC50 values in the low micromolar range. The application of a rational optimization strategy, guided by the determination of the crystal structure of the complex in the kinase domain of PIM1 with compound 1, led to the discovery of compound 15a, which is a potent PIM kinases inhibitor exhibiting excellent selectivity against a large panel of kinases, representative of each family. The synthesis, structure-activity relationship studies, and pharmacokinetic data of compounds from this inhibitor class are presented herein. Furthermore, the cellular activities including inhibition of cell growth and modulation of downstream targets are also described.

Discovery of pyrazolo[1,5-a]pyrimidine-based Pim inhibitors: a template-based approach

The synthesis and hit-to-lead SAR development from a pyrazolo[1,5-a]pyrimidine-derived hit 5 to the identification of a series of potent, pan-Pim inhibitors such as 11j are described.

The PIM family of serine/threonine kinases in cancer

The proviral insertion site in Moloney murine leukemia virus, or PIM proteins, are a family of serine/threonine kinases composed of three different isoforms (PIM1, PIM2, and PIM3) that are highly evolutionarily conserved. These proteins are regulated primarily by transcription and stability through pathways that are controlled by Janus kinase/Signal transducer and activator of transcription, JAK/STAT, transcription factors. The PIM family proteins have been found to be overexpressed in hematological malignancies and solid tumors, and their roles in these tumors were confirmed in mouse tumor models. Furthermore, the PIM family proteins have been implicated in the regulation of apoptosis, metabolism, cell cycle, and homing and migration, which has led to the postulation of these proteins as interesting targets for anticancer drug discovery. In the present work, we review the importance of PIM kinases in tumor growth and as drug targets.

Inhibition of Pim-1 attenuates the proliferation and migration in nasopharyngeal carcinoma cells

OBJECTIVE

To explore the role of proto-oncogene Pim-1 in the proliferation and migration of nasopharyngeal carcinoma (NPC) cells.

METHODS

Pim-1 expressions in NPC cell lines CNE1, CNE1-GL, CNE-2Z and C666-1 were examined by RT-PCR, western blotting and immunoflucesence, respectively. After CNE1, CNE1-GL and C666-1 cells were treated with different concentrations of Pim-1 special inhibitor, quercetagetin, the cell viability, colony formation rate and migration ability were analyzed.

RESULTS

Pim-1 expression was negative in well-differentiated CNE1 cells, whereas expressed weakly positive in poor-differentiated CNE-2Z cells and strongly positive in undifferentiated C666-1 cells. Interestingly, CNE1-GL cells that derived from CNE1 transfected with an Epstein Barr virus latent membrane protein-1 over-expression plasmid displayed stronger expression of Pim-1. Treatment of CNE1-GL and C666-1 cells with quercetagetin significantly decreased the cell viability, colony formation rate and migration ability but not the CNE1 cells.

CONCLUSIONS

These findings suggest that Pim-1 overexpression contributes to NPC proliferation and migration, and targeting Pim-1 may be a potential treatment for anti-Pim-1-expressed NPCs.