Pim-1 Kinase Research Articles

Endothelial Pim3 kinase protects the vascular barrier during lung metastasis

Endothelial cells (ECs) form a tissue-specific barrier for disseminating cancer cells in distant organs. However, the molecular regulation of the ECs in the metastatic niche remains unclear. Here, we analyze using scRNA-Seq, the transcriptional reprogramming of lung ECs six hours after the arrival of melanoma cells in mouse lungs. We discover a reactive capillary EC cluster (rCap) that increases from general capillary ECs in response to infiltrating cancer cells. rCap is enriched for angiogenic and inflammatory pathways and is also found in human lung datasets. The JAK-STAT activated oncogenic Pim3 kinase is a marker of rCap, being upregulated in spontaneous metastasis models. Notably, PIM inhibition increases vascular leakage and metastatic colonization and impairs the EC barrier by decreasing the junctional cadherin-5 and catenins α, β and δ. These results highlight the pulmonary endothelium’s plasticity and its protection by PIM3, which may impair the efficacy of PIM inhibitors in cancer therapies.

PIM Kinase Inhibitors as Novel Promising Therapeutic Scaffolds in Cancer Therapy.

Cancer involves the uncontrolled, abnormal growth of cells and affects other tissues. Kinase has an impact on proliferating the cells and causing cancer. For the purpose of treating cancer, PIM kinase is a potential target. The pro-viral Integration site for moloney murine leukaemia virus (PIM) kinases is responsible for the tumorigenesis, by phosphorylating the proteins that control the cell cycle and cell proliferation. PIM-1, PIM-2, and PIM-3 are the three distinct isoforms of PIM kinases. The JAK/STAT pathway is essential for controlling how PIM genes are expressed. PIM kinase is also linked withPI3K/AKT/mTOR pathway in various types of cancers. The overexpression of PIM kinase will cause cancer. Currently, there are significant efforts being made in medication design and development to target its inhibition. A few small chemical inhibitors (E.g., SGI-1776, AZD1208, LGH447) that specifically target the PIM proteins' adenosine triphosphate (ATP)-binding domain have been identified. PIM kinase antagonists have a remarkable effect on different types of cancer. Despite conducting clinical trials on SGI-1776, the first PIM inhibitory agent, was prematurely withdrawn, making it unable to generate concept evidence. On the other hand, in recent years, it has aided in hastening the identification of multiple new PIM inhibitors. Cyanopyridines and Pyrazolo[1,5-a]pyrimidinecan act as potent PIM kinase inhibitors for cancer therapy. We explore the involvement of oncogenic transcription factor c-Mycandmi-RNA in relation to PIM kinase. In this article, we highlight the oncogenic effects, and structural insights into PIM kinase inhibitors for the treatment of cancer.

Design, synthesis, and anti-breast cancer activity evaluation of novel 3-cyanopyridine derivatives as PIM-1 inhibitors.

A novel series of cyanopyridines 7a-j were synthesized via a one-pot multicomponent reaction of arylidene 4 with ammonium acetate 5 and respective methylaryl/heterylketones 6a-j in ethanol using vanillin as a natural starting material. Moreover, the regioselective alkylation reaction was studied by the treatment of cyanopyridines 7a-f and 7j with CH3I in the presence of K2CO3 in DMF to afford O-methylcyanopyridines 8a-g (major) and N-methylcyanopyridines 9a-g (minor), whereas bipyridine 7h gave bipyridinium iodide salt 10. All of the designed cyanopyridines were evaluated as anti-breast cancer (MCF-7) cell lines via PIM Kinase inhibitory activity, and the results displayed that some of them showed high activities, especially compounds 7h and 8f, which showed excellent activities against MCF-7 with IC50 values of 1.89 and 1.69 μM, respectively, more potent than the reference drug doxorubicin. Mechanistically, compounds 7h and 8f exhibited strong in vitro PIM-1 kinase inhibitory activity with an IC50 of 0.281 and 0.58 μM, respectively, compared to the reference staurosporine. Moreover, compound 7h arrested the tumor cells at the S phase and caused cell death mainly by inducing early and late apoptosis. Molecular docking studies against PIM-1 revealed good binding modes of the synthesized compound and showed agreement with the biological results.

Pim1 inactivating induces RUNX3 upregulation that improves/alleviates airway inflammation and mucus hypersecretion in vitro and in vivo

PurposeOur research aimed to evaluate whether proto-oncogene serine/threonine-protein kinase Pim-1 (Pim1) inactivation could attenuate asthma by promoting runt-related transcription factor 3 (Runx3) expression and explore the underlying molecular mechanism.MethodPhorbol 12-myristate...

Computational Docking studies of Phenyl Acetic Acid Derivatives with Biological Targets, DNA, Protein and Enzyme

Phenyl acetic acid (PAA) is a well-known biomolecule used in antibiotics and drugs. To elucidate the binding modes of PAA and its derivatives with DNA, Pim kinase protein, and urease enzymes, molecular docking studies were conducted. The results revealed that PAA and its derivatives intercalate with DNA, disrupting its structure and potentially affecting replication, transcription, and repair processes. The 3-chloro-PAA showed the highest docking score (-7.809) and significant polar interactions with DNA residues. For Pim kinase, the compounds exhibited polar interactions with key residues, with 2-propyl PAA demonstrating notable inhibitory effects. Similarly, PAA derivatives interacted effectively with urease enzymes, with the 4-propyl-PAA showing a strong docking score (-8.5250). Overall, the meta-substituted PAAs exhibited superior binding interactions compared to ortho and para-substituted derivatives, suggesting their potential as effective inhibitors for these biological targets.

Synthesis of New Xanthene and Acridine Derivatives from Cyclohexan-1,3-dione and the Study of their Antiproliferative Activities

Background: Ionic immobilized liquids and multi-component reactions are integral to green chemistry, facilitating the synthesis of biologically active compounds, such as xanthene and acridine derivatives. These approaches have garnered significant attention in recent years. Objective: The aim of this study was to synthesize novel xanthene and acridine derivatives with diverse substituents and heterocyclic rings. Furthermore, the research sought to evaluate their anticancer activity against various cancer cell lines and analyze their structure-activity relationships (SAR) to determine how structural modifications impact their biological effectiveness. Method: The core compounds in this study were synthesized from cyclohexane-1,3-dione and triethoxymethane under two distinct reaction conditions. The first involved the use of a solvent with either Et₃N or NH₄OAc as a catalyst, while the second employed a solvent-free approach using an ionic liquid catalyst (ILs). Results: The anti-proliferative activity of all synthesized compounds was evaluated against six selected cancer cell lines, revealing that many compounds exhibited significant inhibitory effects. Furthermore, their inhibitory potential against tyrosine kinases and Pim-1 kinases was assessed, along with an investigation of their mechanism of action on tyrosine kinases. Conclusion: The anti-proliferative activity of the newly synthesized compounds was evaluated against six cancer cell lines. Many of the compounds exhibited strong inhibitory effects not only against the tested cancer cell lines but also against tyrosine kinases and Pim-1 kinases.

PIM-1L Kinase Binds to and Inactivates SRPK1: A Biochemical and Molecular Dynamics Study.

SR/RS dipeptide repeats vary in both length and position, and are phosphorylated by SR protein kinases (SRPKs). PIM-1L, the long isoform of PIM-1 kinase, the splicing of which has been implicated in acute myeloid leukemia, contains a domain that consists largely of repeating SR/RS and SH/HS dipeptides (SR/SH-rich). In order to extend our knowledge on the specificity and cellular functions of SRPK1, here we investigate whether PIM-1L could act as substrate of SRPK1 by a combination of biochemical and computational approaches. Our biochemical data showed that the SR/SH-rich domain of PIM-1L was able to associate with SRPK1, yet it could not act as a substrate but, instead, inactivated the kinase. In line with our biochemical data, molecular modeling followed by a microsecond-scale all-atom molecular dynamics (MD) simulation suggests that the SR/SH-rich domain acts as a pseudo-docking peptide that binds to the same acidic docking-groove used in other SRPK1 interactions and induces inactive SRPK1 conformations. Comparative community network analysis of the MD trajectories, unraveled the dynamic architecture of apo SRPK1 and notable alterations of allosteric communications upon PIM-1L peptide binding. This analysis also allowed us to identify key SRPK1 residues, including unique ones, with a pivotal role in mediating allosteric signal propagation within the kinase core. Interestingly, most of the identified amino acids correspond to cancer-associated amino acid changes, validating our results. In total, this work provides insights not only on the details of SRPK1 inhibition by the PIM-1L SR/SH-domain, but also contributes to an in-depth understanding of SRPK1 regulation.

Inhibition of PIM kinase in tumor associated macrophages suppresses inflammasome activation and sensitizes prostate cancer to immunotherapy.

Immunotherapy has changed the treatment paradigm for many types of cancer, but immune checkpoint inhibitors (ICIs) have not shown benefit in prostate cancer (PCa). Chronic inflammation contributes to the immunosuppressive prostate tumor microenvironment (TME) and is associated with poor response to ICIs. The primary source of inflammatory cytokine production is the inflammasome. Here, we identify PIM kinases as important regulators of inflammasome activation in tumor associated macrophages (TAMs). Analysis of clinical data from a cohort of treatment naïve, hormone responsive PCa patients revealed that tumors from patients with high PIM1/2/3 display an immunosuppressive TME characterized by high inflammation (IL-1β and TNFα) and a high density of repressive immune cells, most notably TAMs. Strikingly, macrophage-specific knockout of PIM reduced tumor growth in syngeneic models of prostate cancer. Transcriptional analyses indicate that eliminating PIM from macrophages enhanced the adaptive immune response and increased cytotoxic immune cells. Combined treatment with PIM inhibitors and ICIs synergistically reduced tumor growth. Immune profiling revealed that PIM inhibitors sensitized PCa tumors to ICIs by increasing tumor suppressive TAMs and increasing the activation of cytotoxic T cells. Collectively, our data implicate macrophage PIM as a driver of inflammation that limits the potency of ICIs and provides preclinical evidence that PIM inhibitors are an effective strategy to improve the efficacy of immunotherapy in prostate cancer.

Targeting STAT3, FOXO3a, and Pim-1 kinase by FDA-approved tyrosine kinase inhibitor-Radotinib: An in silico and in vitro approach.

Cancer, a multifactorial pathological condition, is primarily caused due to mutations in multiple genes. Hepatocellular carcinoma (HCC) is a form of primary liver cancer that is often diagnosed at the advanced stage. Current treatment strategies for advanced HCC involve systemic therapies which are often hindered due to the emergence of resistance and toxicity. Therefore, a multitarget approach might prove more effective in HCC treatment. The present study focuses on targeting signal transducer and activator of transcription 3 (STAT3), forkhead box class O3a (FOXO3a), and proviral integration site for Moloney murine leukemia virus-1 (Pim-1) kinase, using a Food and Drug Administration (FDA)-approved anticancer drug library. Two compounds, namely, radotinib and capmatinib, were identified as top compounds using molecular docking. Among the two compounds, radotinib exhibited significant binding values towards the targeted proteins and their heterodimers. Furthermore, in vitro experiments involving 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), live/dead, 4',6-diamidino-2-phenylindole, and clonogenic assays were performed to evaluate the effect of radotinib in human hepatoblastoma cell line/hepatocellular carcinoma cells. The gene expression data indicated reduced expression of FOXO3a and Pim-1, but no basal-level alteration of STAT3. The Western blot analysis assay showed that the phosphorylation level of STAT3 was significantly decreased upon radotinib treatment. Taken together, our findings suggest that radotinib, which is currently used in the treatment of chronic myeloid leukemia (CML), could be considered as a potential candidate for repurposing in the treatment of HCC.

Comparative in Silico study of apigenin and its dimeric forms on PIM1 kinase in glioblastoma multiform

This study aimed to investigate and compare the binding affinity of apigenin and its dimeric flavonoid forms to PIM1 kinase in glioblastoma multiforme (GBM), an aggressive and lethal brain cancer. Apigenin is a natural herbal product that has demonstrated anti-cancer effects in numerous studies, both in vitro and in vivo, on various cancers. Our in silico analysis showed that PIM1 expression was significantly higher in GBM tumor tissue compared to normal brain tissue, and high PIM1 expression correlated with worse survival rates in patients with GBM. Also, our molecular docking studies showed that apigenin and its dimeric flavonoids, such as amentoflavone and hinokiflavone, can bind to the ATP-binding site of PIM1 with significant binding affinity and form various intermolecular interactions with key amino acid residues. Notably, dimeric flavonoids have a stronger binding affinity than apigenin, indicating their potential as potent PIM1 inhibitors. Our findings demonstrated the therapeutic potential of apigenin and its dimeric flavonoid forms in treating GBM by targeting PIM1 kinase. The observed inhibitory effects of PIM1 can inhibit tumor growth, induce cell cycle arrest, and promote apoptosis. However, further in vitro and in vivo studies are needed to confirm their anticancer potentials and elucidate the underlying molecular mechanisms of these compounds in GBM treatment.

Molecular insights and inhibitory dynamics of flavonoids in targeting Pim-1 kinase for cancer therapy.

Pim-1 kinase, a serine/threonine kinase, is often overexpressed in various cancers, contributing to disease progression and poor prognosis. In this study, we explored the potential of flavonoids as inhibitors of Pim-1 kinase using a combination of molecular docking and steered molecular dynamics (SMD) simulations. Our docking studies revealed two main binding orientations for the flavonoid molecules. The SMD simulations showed that the binding mode with higher pulling forces was linked to stronger inhibitory activity, with a strong positive correlation (R 2 ≈ 0.92) between pulling forces and IC50 values. Quercetin stood out as the most potent inhibitor, showing a pulling force of about 820pN and an IC_(5) 0 of less than 6µM. Further dynamic simulations indicated that quercetin's hydroxyl groups at the C3, C-5 and C-7 positions formed stable hydrogen bonds with key residues GLU-121, Leu-44 and Val-126, respectively enhancing its binding stability and effectiveness. Our results emphasized the critical role of the hydroxyl group at the C-3 position, which plays a pivotal function in effectively anchoring these molecules in the active site of Pim-1 kinase. Principal component analysis (PCA) of Pim-1 kinase's conformational changes revealed that potent inhibitors like quercetin, galangin, and kaempferol significantly restricted the enzyme's flexibility, suggesting potential inhibitory effect. These findings provide insights into the structural interactions between flavonoids and Pim-1 kinase, offering a foundation for future experimental investigations. However, further studies, including in vitro and in vivo validation, are necessary to assess the pharmacological relevance and specificity of flavonoids in cancer therapy.

In silico design and ADMET evaluation of new inhibitors for PIM1 kinase using QSAR studies, molecular docking, and molecular dynamic simulation

The proviral Integration site of Moloney (PIM) kinase is highly expressed in various diseases, including cancer, making the development of selective inhibitors for this protein important. A series of PIM1 inhibitors, triazolo [4, 3-b] pyridazin-3-yl-quinoline derivatives, have been studied to design new inhibitors. The activity and structural features of these derivatives were investigated to understand their interactions with PIM1 using molecular docking, molecular dynamic simulation, and QSAR techniques.In a study of 30 compounds using the structure-activity technique and the MLR method, a linear model with R2train = 0.91 and R2test = 0.96 was obtained. The model utilized descriptors such as RDF080v, RDF105v, RDF135v, Mor03v, and H046 to express the structural characteristics of the inhibitors. To enhance the model, the SVR non-linear method with the RBF function was also used, resulting in an improved model with R2train = 0.98 and R2test = 0.98.Furthermore, the molecular docking technique was employed to investigate the interaction of compounds with high (compound 25) and low (compound 13) inhibitory activity. It was observed that the rings with nitrogen atoms interacted with the protein. The molecular binding results indicate that groups such as OMe and rings with Nitrogen can enhance the inhibitory activity of the compounds. Additionally, oxygen and nitrogen atoms contribute to an increased number of hydrogen bonds, thereby increasing the inhibitory activity of the compounds.Additionally, the stability and bonding modes of active and inactive compounds were studied using molecular dynamic simulation. Based on the results, four new inhibitors were designed, demonstrating better inhibition efficiency with the PIM1 kinase compared to the reference compounds. Moreover, the designed compounds underwent evaluation for ADMET, yielding promising results.

PIM1 kinase promotes EMT-associated osimertinib resistance via regulating GSK3β signaling pathway in EGFR-mutant non-small cell lung cancer

Acquired resistance is inevitable in the treatment of non-small cell lung cancer (NSCLC) with osimertinib, and one of the primary mechanisms responsible for this resistance is the epithelial-mesenchymal transition (EMT). We identify upregulation of the proviral integration site for Moloney murine leukemia virus 1 (PIM1) and functional inactivation of glycogen synthase kinase 3β (GSK3β) as drivers of EMT-associated osimertinib resistance. Upregulation of PIM1 promotes the growth, invasion, and resistance of osimertinib-resistant cells and is significantly correlated with EMT molecules expression. Functionally, PIM1 suppresses the ubiquitin-proteasome degradation of snail family transcriptional repressor 1 (SNAIL) and snail family transcriptional repressor 2 (SLUG) by deactivating GSK3β through phosphorylation. The stability and accumulation of SNAIL and SLUG facilitate EMT and encourage osimertinib resistance. Furthermore, treatment with PIM1 inhibitors prevents EMT progression and re-sensitizes osimertinib-resistant NSCLC cells to osimertinib. PIM1/GSK3β signaling is activated in clinical samples of osimertinib-resistant NSCLC, and dual epidermal growth factor receptor (EGFR)/PIM1 blockade synergistically reverse osimertinib-resistant NSCLC in vivo. These data identify PIM1 as a driver of EMT-associated osimertinib-resistant NSCLC cells and predict that PIM1 inhibitors and osimertinib combination therapy will provide clinical benefit in patients with EGFR-mutant NSCLC.

Exploring the anticancer potential of new 3-cyanopyridine derivatives bearing N-acylhydrazone motif: Synthesis, DFT calculations, cytotoxic evaluation, molecular modeling, and antioxidant properties.

3-Cyanopyridine derivatives are known for exhibiting excellent anticancer activity due to their strong capability to inhibit various biological targets, including Pim-1 kinase, survivin, and tubulin polymerization. On the other hand, N-acylhydrazones (NAH) are known to be a very versatile motif in medicinal chemistry and drug design. Based on these data, we report in this paper, the synthesis of novel 3-cyanopyridines incorporating N-acyl hydrazine scaffold, the evaluation of their cytotoxicity on the breast (MCF-7) and ovarian (A-2780) cancer cell lines and their antioxidant properties. Excluding 4a and 4d, all tested molecules exhibited high cytotoxicity against A-2780, with IC50 values ranging from 1.14 to 1.76 µM. Conversely, only four molecules 3d, 4b, 4c, and 4d demonstrated cytotoxicity against MCF-7, with IC50 values ranging from 1.14 to 3.38 µM. On the other hand, all the tested molecules exhibited a moderate antioxidant capacity in both the DPPH and metal chelation assays. Docking and molecular dynamics studies revealed that 2d, 3d, and 4d are potential inhibitors of tubulin and the œstrogen receptor, which may explain their high cytotoxicity. These results are promising to study these newly synthesized 3-cyanopyridine-N-acylhydrazones in depth for use as potential anticancer candidates.

PROTACs as Therapeutic Modalities for Drug Discovery in Castration-Resistant Prostate Cancer.

Castration-resistant prostate cancer (CRPC) presents significant challenges in clinical management due to its resistance to conventional androgen receptor (AR)-targeting therapies. The advent of proteolysis targeting chimeras (PROTACs) has revolutionized cancer therapy by enabling the targeted degradation of key molecular players implicated in CRPC progression. In this review we discuss the developments of PROTACs for CRPC treatment, focusing on AR and other CRPC-associated regulators. We provide an overview of the strategic trends in AR PROTAC development from the aspect of targeting site selection and preclinical antitumor evaluation, as well as updates on AR degraders in clinical applications. Additionally, we briefly address the current status of selective AR degrader development. Furthermore, we review new developments in PROTACs as potential CRPC treatment paradigms, highlighting those targeting chromatin modulators BRD4, EZH2, and SWI/SNF; transcription regulator SMAD3; and kinases CDK9 and PIM1. Given the molecular targets shared between CRPC and neuroendocrine prostate cancer (NEPC), we also discuss the potential of PROTACs in addressing NEPC.

Cs2CO3-Promoted Alkylation of 3-Cyano-2(1H)-Pyridones: Anticancer Evaluation and Molecular Docking.

Herein, a Cs2CO3-promoted N-alkylation of 3-cyano-2(1H)-pyridones containing alkyl groups with diverse alkyl halides to synthesize N-alkyl-2-pyridones over O-alkylpyridines is reported. The use of alkyl dihalides resulted in complex mixtures of N- and O-alkylated products. The primary factor influencing regioselectivity in these reactions is the electronic effects of substituents on the 2(1H)-pyridone ring, as evidenced by the preferential formation of O-alkylpyridines upon the introduction of aryl groups. Remarkably, we efficiently employed CuAAC and Ti(Oi-Pr)4-catalyzed amidation reactions to functionalize N-alkyl-2-pyridones containing propargyl and ester groups, leading to the synthesis of 1,2,3-triazoles and amides, respectively. Moreover, O-alkylpyridines 10 b and 10 d displayed remarkable selectivity toward the A-498 renal cancer cell line with growth inhibition percentages (%GI) of 54.75 and 67.64, respectively. The binding modes of compounds 10 b and 10 d to the PIM-1 kinase enzyme were determined through molecular docking studies.

The role of Pim-1 kinases in inflammatory signaling pathways.

This observational study investigated the regulatory mechanism of Pim-1 in inflammatory signaling pathways. THP-1, RAW 264.7, BV2, and Jurkat human T cell lines were used. None. Lipopolysaccharide (LPS) was used to induce inflammation, followed by PIM1 knockdown. Western blot, immunoprecipitation, immunofluorescence, and RT-PCR assays were used to assess the effect of PIM1 knockdown on LPS-induced inflammation. PIM1 knockdown in macrophage-like THP-1 cells suppressed LPS-induced upregulation of pro-inflammatory cytokines, inducible nitric oxide synthase, cyclooxygenase-2, phosphorylated Janus kinase, signal transducer and activator of transcription 3, extracellular signal-regulated kinase, c-Jun N-terminal kinase, p38, and nuclear factor kappa B p65 (NF-κB p65). It also suppressed upregulation of inhibitor of NF-κB kinase α/β and enhanced the nuclear translocation of NF-κB p65. Moreover, it inhibited the upregulation of Nod-like receptor family pyrin domain-containing 3 (NLRP3) and cleavage of caspase-1 induced by co-treatment of LPS with adenosine triphosphate. Additionally, p-transforming growth factor-β-activated kinase 1 (TAK1) interacted with Pim-1. All three members of Pim kinases (Pim-1, Pim-2, and Pim-3) were required for LPS-mediated inflammation in macrophages; however, unlike Pim-1 and Pim-3, Pim-2 functioned as a negative regulator of T cell activity. Pim-1 interacts with TAK1 in LPS-induced inflammatory responses and is involved in MAPK/NF-κB/NLRP3 signaling pathways. Additionally, considering the negative regulatory role of Pim-2 in T cells, further in-depth studies on their respective functions are needed.

Targeting prostate cancer via therapeutic targeting of PIM-1 kinase by Naringenin and Quercetin

PIM-1 kinase belongs to the Ser/Thr kinases family, an attractive therapeutic target for prostate cancer. Here, we screened about 100 natural substances to find potential PIM-1 inhibitors. Two natural compounds, Naringenin and Quercetin, were finally selected based on their PIM-1 inhibitory potential and binding affinities. The docking score of Naringenin and Quercetin with PIM-1 is −8.4 and − 8.1 kcal/mol, respectively. Fluorescence binding studies revealed a strong affinity (Ka values, 3.1 × 104 M−1 and 4.6 × 107 M−1 for Naringenin and Quercetin, respectively) with excellent IC50 values for Naringenin and Quercetin (28.6 μM and 34.9 μM, respectively). Both compounds inhibited the growth of prostate cancer cells (LNCaP) in a dose-dependent manner, with the IC50 value of Naringenin at 17.5 μM and Quercetin at 8.88 μM. To obtain deeper insights into the PIM-1 inhibitory effect of Naringenin and Quercetin, we performed extensive molecular dynamics simulation studies, which provided insights into the binding mechanisms of PIM-1 inhibitors. Finally, Naringenin and Quercetin were suggested to serve as potent PIM-1 inhibitors, offering targeted treatments of prostate cancer. In addition, our findings may help to design novel Naringenin and Quercetin derivatives that could be effective in therapeutic targeting of prostate cancer.

Pim Kinase Inhibition Disrupts CXCR4 Signalling in Megakaryocytes and Platelets by Reducing Receptor Availability at the Surface.

A key step in platelet production is the migration of megakaryocytes to the vascular sinusoids within the bone marrow. This homing is mediated by the chemokine CXCL12 and its receptor CXCR4. CXCR4 is also a positive regulator of platelet activation and thrombosis. Pim-1 kinase has been shown to regulate CXCR4 signalling in other cell types, and we have previously described how Pim kinase inhibitors attenuate platelet aggregation to CXCL12. However, the mechanism by which Pim-1 regulates CXCR4 signalling in platelets and megakaryocytes has yet to be elucidated. Using human platelets, murine bone marrow-derived megakaryocytes, and the megakaryocyte cell line MEG-01, we demonstrate that pharmacological Pim kinase inhibition leads to reduced megakaryocyte and platelet function responses to CXCL12, including reduced megakaryocyte migration and platelet granule secretion. Attenuation of CXCL12 signalling was found to be attributed to the reduced surface expression of CXCR4. The decrease in CXCR4 surface levels was found to be mediated by rapid receptor internalisation, in the absence of agonist stimulation. We demonstrate that pharmacological Pim kinase inhibition disrupts megakaryocyte and platelet function by reducing constitutive CXCR4 surface expression, decreasing the number of receptors available for agonist stimulation and signalling. These findings have implications for the development and use of Pim kinase inhibitors for the treatment of conditions associated with elevated circulating levels of CXCL12/SDF1α and increased thrombotic risk.

Evaluating the Physicochemical Properties-Activity Relationship and Discovering New 1,2-Dihydropyridine Derivatives as Promising Inhibitors for PIM1-Kinase: Evidence from Principal Component Analysis, Molecular Docking, and Molecular Dynamics Studies.

In this study, we evaluated the physicochemical properties related to the previously reported anticancer activity of a dataset comprising thirty 1,2-dihydropyridine derivatives. We utilized Principal Component Analysis (PCA) to identify the most significant influencing factors. The PCA analysis showed that the first two principal components accounted for 59.91% of the total variance, indicating a strong correlation between the molecules and specific descriptors. Among the 239 descriptors analyzed, 18 were positively correlated with anticancer activity, clustering with the 12 most active compounds based on their IC50 values. Six of these variables-LogP, Csp3, b_1rotN, LogS, TPSA, and lip_don-are related to drug-likeness potential. Thus, we then ranked the 12 compounds according to these six variables and excluded those violating the drug-likeness criteria, resulting in a shortlist of nine compounds. Next, we investigated the binding affinity of these nine shortlisted compounds with the use of molecular docking towards the PIM-1 Kinase enzyme (PDB: 2OBJ), which is overexpressed in various cancer cells. Compound 6 exhibited the best docking score among the docked compounds, with a docking score of -11.77 kcal/mol, compared to -12.08 kcal/mol for the reference PIM-1 kinase inhibitor, 6-(5-bromo-2-hydroxyphenyl)-2-oxo-4-phenyl-1,2-dihydropyridine-3-carbonitrile. To discover new PIM-1 kinase inhibitors, we designed nine novel compounds featuring hybrid structures of compound 6 and the reference inhibitor. Among these, compound 31 displayed the best binding affinity, with a docking score of -13.11 kcal/mol. Additionally, we performed PubChem database mining using the structure of compound 6 and the similarity search tool, identifying 16 structurally related compounds with various reported biological properties. Among these, compound 52 exhibited the best binding affinity, with a docking score of -13.03 kcal/mol. Finally, molecular dynamics (MD) studies were conducted to confirm the stability of the protein-ligand complexes obtained from docking the studied compounds to PIM-1 kinase, validating the potential of these compounds as PIM-1 kinase inhibitors.