Discovery of novel triazolo[4,3-b]pyridazin-3-yl-quinoline derivatives as PIM inhibitors

Dual Targeting of Pim and PI3 Kinases in Mature T-Cell Lymphoma

Provirus Integration site for Moloney leukemia virus (Pim) family members are well-known oncogenes, with an expression that is restricted to few cell types including hematopoietic cells in adult organisms, making it a promising target for lymphoma treatment. Indeed, previous studies in mature T-cell lymphoma (mTCL) cells revealed frequent upregulation of Pim expression. Nevertheless, inhibition of Pim kinases showed only minor effects on the viability of mTCL cells so far. Thus, we here addressed cellular responses to therapeutic inhibition of Pim kinases and identified a PI3K/Akt-driven activation of mTOR as a significant escape mechanism mitigating the anti-lymphoma effects of Pim inhibition. Indeed, dual inhibition of Pim and PI3 kinases showed synergistic anti-lymphoma effects in vitro through downregulation of mTOR-induced protein translation and mitigation of BCL-xL-mediated anti-apoptotic mechanisms. Based on this finding, we next explored the therapeutic potential of the dual Pim/PI3K inhibitor IBL-202 in mTCL cell lines. Strikingly, IBL-202 strongly induced cell-cycle-dependent cell death in cell lines of different mTCL subtypes. Together, our study provides mechanistic evidence supporting a therapeutic strategy of dual Pim- and PI3-kinase inhibition in mature T-cell lymphoma.

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 R2 train = 0.91 and R2 test = 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 R2 train = 0.98 and R2 test = 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.

Novel Triazole-Containing "Dipeptides": Synthesis, Molecular Docking and Analgesic Activity Studies

Dipeptides of a new structure based on β-triazolalanines and (L)-α-amino acids were synthesized and optimal conditions were developed that ensure both chemical and optical purity of the final products. Molecular docking was carried out and possible intermolecular interactions of dipeptides with potential targets were established. Based on these studies, the analgesic property of chosen dipeptides was studied and it was found that some compounds possess revealed antinociceptive activity in the tail-flick test.

Assessment of structural and activity-related contributions of various PIM-1 kinase inhibitors in the treatment of leukemia and prostate cancer

One of the most perilous illnesses in the world is cancer. The cancer may be associated with the mutation of different genes inside the body. The PIM kinase, also known as the serine/threonine kinase, plays a critical role in the biology of different kinds of cancer. They are widely distributed and associated with several biological processes, including cell division, proliferation, and death. Aberration of PIM-1 kinase is found in varieties of cancer. Prostate cancer and leukemia can both be effectively treated with PIM-1 kinase inhibitors. There are several potent compounds that have been explored in this review based on heterocyclic compounds for the treatment of prostate cancer and leukemia that have strong effects on the suppression of PIM-1 kinase. The present review summarizes the PIM-1 kinase pathway, their inhibitors under clinical trial, related patents, and SAR studies of several monocyclic, bicyclic, and polycyclic compounds. The study related to their molecular interactions with receptors is also included in the present manuscript. The study may be beneficial to scientists for the development of novel compounds as PIM-1 inhibitors in the treatment of prostate cancer and leukemia.

Targeting PIM kinases in cancer therapy: An update on pharmacological small-molecule inhibitors

PIM kinases, a serine/threonine kinase family with three isoforms, has been well-known to participate in multiple physiological processes by phosphorylating various downstream targets. Accumulating evidence has recently unveiled that aberrant upregulation of PIM kinases (PIM1, PIM2, and PIM3) are closely associated with tumor cell proliferation, migration, survival, and even resistance. Inhibiting or silencing of PIM kinases has been reported have remarkable antitumor effects, such as anti-proliferation, pro-apoptosis and resensitivity, indicating the therapeutic potential of PIM kinases as potential druggable targets in many types of human cancers. More recently, several pharmacological small-molecule inhibitors have been preclinically and clinically evaluated and showed their therapeutic potential; however, none of them has been approved for clinical application so far. Thus, in this perspective, we focus on summarizing the oncogenic roles of PIM kinases, key signaling network, and pharmacological small-molecule inhibitors, which will provide a new clue on discovering more candidate antitumor drugs targeting PIM kinases in the future.

Deaminative Cyclization of Tertiary Amines for the Synthesis of 2-Arylquinoline Derivatives with a Nonsubstituted Vinylene Fragment

With triethylamine as a vinylene source, a convenient protocol for the regioselective synthesis of β,γ-nonsubstituted 2-arylquinolines from aldehydes and arylamines has been accomplished. The deaminative cyclization is also extended to long-chain tertiary alkylamines, enabling diverse alkyl groups to be concurrently installed into the pyridine rings. This process demonstrates a new conversion pathway for the simultaneous dual C(sp³)-H bond functionalization of tertiary amines, wherein the transient acyclic enamines generated in situ undergo the Povarov reaction.

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.

Hybrids of Imatinib with Quinoline: Synthesis, Antimyeloproliferative Activity Evaluation, and Molecular Docking

Imatinib (IMT) is the first-in-class BCR-ABL commercial tyrosine kinase inhibitor (TKI). However, the resistance and toxicity associated with the use of IMT highlight the importance of the search for new TKIs. In this context, heterocyclic systems, such as quinoline, which is present as a pharmacophore in the structure of the TKI inhibitor bosutinib (BST), have been widely applied. Thus, this work aimed to obtain new hybrids of imatinib containing quinoline moieties and evaluate them against K562 cells. The compounds were synthesized with a high purity degree. Among the produced molecules, the inhibitor 4-methyl-N3-(4-(pyridin-3-yl)pyrimidin-2-yl)-N1-(quinolin-4-yl)benzene-1,3-diamine (2g) showed a suitable reduction in cell viability, with a CC₅₀ value of 0.9 µM (IMT, CC₅₀ = 0.08 µM). Molecular docking results suggest that the interaction between the most active inhibitor 2g and the BCR-ABL1 enzyme occurs at the bosutinib binding site through a competitive inhibition mechanism. Despite being less potent and selective than IMT, 2g is a suitable prototype for use in the search for new drugs against chronic myeloid leukemia (CML), especially in patients with acquired resistance to IMT.

Recent contributions of quinolines to antimalarial and anticancer drug discovery research

Quinoline, a privileged scaffold in medicinal chemistry, has always been associated with a multitude of biological activities. Especially in antimalarial and anticancer research, quinoline played (and still plays) a central role, giving rise to the development of an array of quinoline-containing pharmaceuticals in these therapeutic areas. However, both diseases still affect millions of people every year, pointing to the necessity of new therapies. Quinolines have a long-standing history as antimalarial agents, but established quinoline-containing antimalarial drugs are now facing widespread resistance of the Plasmodium parasite. Nevertheless, as evidenced by a massive number of recent literature contributions, they are still of great value for future developments in this field. On the other hand, the number of currently approved anticancer drugs containing a quinoline scaffold are limited, but a strong increase and interest in quinoline compounds as potential anticancer agents can be seen in the last few years. In this review, a literature overview of recent contributions made by quinoline-containing compounds as potent antimalarial or anticancer agents is provided, covering publications between 2018 and 2020.

Design and synthesis of a novel mitochondria-targeted osteosarcoma theranostic agent based on a PIM1 kinase inhibitor

Osteosarcoma (OS) is the most common malignancy of the skeletal system, with a poor prognosis and high rate of recurrence. Adequate surgical margin and adjuvant chemotherapy improve the overall survival and limb salvage rate of osteosarcoma patients. Previous studies have showed that OS exhibits an increase in the expression of proviral integration site for Moloney murine leukemia virus 1 (PIM1) kinase, and high levels of PIM1 are also associated with poor OS prognosis and metastasis. We exploited the overexpression of proto-oncogenic PIM1 in OS towards the development of a novel near-infrared imaging and targeted therapeutic agent, namely QCAi-Cy7d by conjugating a PIM1 small molecule inhibitor and heptamethine cyanine dye, for simultaneous guiding surgery and chemotherapy. QCAi-Cy7d showed targeted imaging and anticancer activities against OS in vitro and vivo without any obvious toxicity, and its antitumoral activity was much greater than the parent PIMI inhibitor. These results demonstrated the potential of new conjugate of PIM1 inhibitor and near-infrared imaging, supporting structure-based design and development of theranostic agents for precise tumor imaging and targeted treatment.

An insight on medicinal attributes of 1,2,4-triazoles

The present review aims to summarize the pharmacological profile of 1,2,4-triazole, one of the emerging privileged scaffold, as antifungal, antibacterial, anticancer, anticonvulsant, antituberculosis, antiviral, antiparasitic, analgesic and anti-inflammatory agents, etc. along with structure-activity relationship. The comprehensive compilation of work carried out in the last decade on 1,2,4-triazole nucleus will provide inevitable scope for researchers for the advancement of novel potential drug candidates having better efficacy and selectivity.

Pyridazine as a privileged structure: An updated review on anticancer activity of pyridazine containing bioactive molecules

Identification of potent anticancer agents with high selectivity and low toxicity remains on the way to human health. Pyridazine featuring advantageous physicochemical properties and antitumor potential usually is regarded as a central core in numerous anticancer derivatives. There are several approved pyridazine-based drugs in the market and analogues currently going through different clinical phases or registration statuses, suggesting pyridazine as a promising drug-like scaffold. The current review is intended to provide a comprehensive and updated overview of pyridazine derivatives as potential anticancer agents. In particular, we focused on their structure-activity relationship (SAR) studies, design strategies, binding modes and biological activities in the hope of offering novel insights for further rational design of more active and less toxic anticancer drugs.

Pim kinase inhibitors in cancer: medicinal chemistry insights into their activity and selectivity

The oncogenic Pim kinase proteins (Pim-1/2/3) regulate tumorigenesis through phosphorylating essential proteins that control cell cycle and proliferation. Pim kinase is a potential chemotherapeutic target in cancer and its inhibition is currently the focus of intensive drug design and development efforts. The distinctive presence of proline amino acids in the hinge region provides an opportunity to inhibit Pim kinase while conserving the physiological functions of other kinases and reducing the toxicity profiles of the inhibitors. Various Pim kinase inhibitors have been clinically evaluated for the treatment of hematological cancers, yet none has reached the clinic. In this review, we discuss the design and development of selective and potent Pim inhibitors with novel chemotypes focusing on structural features essential for high potency and selectivity.

The different modes of chiral [1,2,3]triazolo[5,1-b][1,3,4]thiadiazines: crystal packing, conformation investigation and cellular activity

The crystal structures of four new chiral [1,2,3]triazolo[5,1-b][1,3,4]thiadiazines are described, namely, ethyl 5'-benzoyl-5'H,7'H-spiro[cyclohexane-1,6'-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine]-3'-carboxylate, C₁₉H₂₂N₄O₃S, ethyl 5'-(4-methoxybenzoyl)-5'H,7'H-spiro[cyclohexane-1,6'-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine]-3'-carboxylate, C₂₀H₂₄N₄O₄S, ethyl 6,6-dimethyl-5-(4-methylbenzoyl)-6,7-dihydro-5H-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine-3-carboxylate, C₁₇H₂₀N₄O₃S, and ethyl 5-benzoyl-6-(4-methoxyphenyl)-6,7-dihydro-5H-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine-3-carboxylate, C₂₁H₂₀N₄O₄S. The crystallographic data and cell activities of these four compounds and of the structures of three previously reported similar compounds, namely, ethyl 5'-(4-methylbenzoyl)-5'H,7'H-spiro[cyclopentane-1,6'-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine]-3'-carboxylate, C₁₉H₂₂N₄O₃S, ethyl 5'-(4-methoxybenzoyl)-5'H,7'H-spiro[cyclopentane-1,6'-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine]-3'-carboxylate, C₁₉H₂₂N₄O₄S, and ethyl 6-methyl-5-(4-methylbenzoyl)-6-phenyl-6,7-dihydro-5H-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine-3-carboxylate, C₂₂H₂₂N₄O₃S, are contrasted and compared. For both crystallization and an MTT assay, racemic mixtures of the corresponding [1,2,3]triazolo[5,1-b][1,3,4]thiadiazines were used. The main manner of molecular packing in these compounds is the organization of either enantiomeric pairs or dimers. In both cases, the formation of two three-centre hydrogen bonds can be detected resulting from intramolecular N-H...O and intermolecular N-H...O or N-H...N interactions. Molecules of different enantiomeric forms can also form chains through N-H...O hydrogen bonds or form layers between which only weak hydrophobic contacts exist. Unlike other [1,2,3]triazolo[5,1-b][1,3,4]thiadiazines, ethyl 5'-benzoyl-5'H,7'H-spiro[cyclohexane-1,6'-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazine]-3'-carboxylate contains molecules of only the (R)-enantiomer; moreover, the N-H group does not participate in any significant intermolecular interactions. Molecular mechanics methods (force field OPLS3e) and the DFT B3LYP/6-31G+(d,p) method show that the compound forming enantiomeric pairs via weak N-H...N hydrogen bonds is subject to greater distortion of the geometry under the influence of the intermolecular interactions in the crystal. For intramolecular N-H...O and S...O interactions, an analysis of the noncovalent interactions (NCIs) was carried out. The cellular activities of the compounds were tested by evaluating their antiproliferative effect against two normal human cell lines and two cancer cell lines in terms of half-maximum inhibitory concentration (IC₅₀). Some derivatives have been found to be very effective in inhibiting the growth of Hela cells at nanomolar and submicromolar concentrations with minimal cytotoxicity in relation to normal cells.

Induction of Lysosome Membrane Permeabilization as a Therapeutic Strategy to Target Pancreatic Cancer Stem Cells

Despite significant efforts to improve pancreatic ductal adenocarcinoma (PDAC) clinical outcomes, overall survival remains dismal. The poor response to current therapies is partly due to the existence of pancreatic cancer stem cells (PaCSCs), which are efficient drivers of PDAC tumorigenesis, metastasis and relapse. To find new therapeutic agents that could efficiently kill PaCSCs, we screened a chemical library of 680 compounds for candidate small molecules with anti-CSC activity, and identified two compounds of a specific chemical series with potent activity in vitro and in vivo against patient-derived xenograft (PDX) cultures. The anti-CSC mechanism of action of this specific chemical series was found to rely on induction of lysosomal membrane permeabilization (LMP), which is likely associated with the increased lysosomal mass observed in PaCSCs. Using the well characterized LMP-inducer siramesine as a tool molecule, we show elimination of the PaCSC population in mice implanted with tumors from two PDX models. Collectively, our approach identified lysosomal disruption as a promising anti-CSC therapeutic strategy for PDAC.