Targeting phosphoinositide 3-kinase: moving towards therapy

Epigenetic activation of PTEN by valproic acid inhibits PI3K/AKT signaling and Burkitt lymphoma cell growth

Histone deacetylase (HDAC) inhibitors show promise in treating Burkitt lymphoma (BL), although the precise mechanisms remain unclear. We investigated the effects of valproic acid (VPA), a specific HDAC inhibitor, on BL cell lines RAJI and CA46, focusing on the PTEN/PI3K/AKT pathway. Cell viability, cell cycle progression, and apoptosis were evaluated using the Cell Counting Kit-8 assay and the Annexin V-fluorescein isothiocyanate assay. Chromatin immunoprecipitation sequencing (ChIP-seq) assessed acetylation at the PTEN promoter, while gene expression and protein levels were measured via reverse transcription quantitative polymerase chain reaction and Western blotting, respectively. VPA treatment significantly reduced BL cell viability and induced apoptosis and cell cycle arrest in a dose-dependent manner. Compared to peripheral blood mononuclear cells, BL cells exhibited significantly higher HDAC mRNA and protein levels. ChIP-seq analysis revealed increased acetylation of the PTEN promoter following exposure to VPA. After treatment with 4 mM VPA, PTEN protein levels in BL cells increased significantly, while levels of HDAC, p-AKT, and p-p70S6K proteins decreased markedly. Furthermore, compared to VPA treatment alone, the combination of VPA and the PI3K inhibitor BEZ235 led to even greater PTEN protein expression, further decreased p-AKT and p-p70S6K protein levels, and further reduced cell viability in BL cells. VPA exerts its antitumor effects in BL cells by modulating the PTEN/PI3K/AKT pathway through the inhibition of HDAC1.

Interleukin-7 promotes porcine early embryogenesis in vitro and inner cell mass development through PI3K/AKT pathway after parthenogenetic activation

Interleukin-7 (IL-7) plays a crucial role in cell survival and proliferation through the phosphatidylinositol-3-kinase (PI3K)/AKT signaling. While we previously demonstrated the beneficial role of IL-7 in early porcine embryonic development, the underlying molecular mechanisms remained unclear. We hypothesized that IL-7 would enhance early embryogenesis and promote inner cell mass (ICM) formation via PI3K/AKT pathway activation. To test this, embryos were cultured with wortmannin (Wort), a PI3K inhibitor, with or without IL-7 after parthenogenetic activation. IL-7 supplementation significantly increased cleavage and blastocyst formation rates compared to the control (p < 0.05), while mitigating Wort-induced developmental impairment. Moreover, IL-7 significantly reduced blastocyst apoptosis and increased total cell numbers compared to the control (p < 0.05), thereby counteracting pro-apoptotic effects of Wort. Furthermore, IL-7 treatment significantly promoted ICM formation through the PI3K/AKT pathway, as demonstrated by increased SOX2 + cell numbers and ICM-specific gene expression, with elevated phosphorylated AKT levels compared to the control (p < 0.05). Notably, IL-7 significantly improved mitochondrial function and biogenesis-related gene expression compared to the control (p < 0.05) through a PI3K/AKT-independent pathway. These findings suggest that IL-7-mediated PI3K/AKT signaling enhances porcine early embryonic development in vitro, providing insights into mechanisms that regulate early embryonic development in mammals.

Exploring the antiproliferative and proapoptotic activities of new pyridopyrimidine derivatives and their analogs

This study investigates a series of newly synthesized compounds, including pyridopyrimidine derivatives (9a-g), tricyclic pyridotriazolopyrimidine analogs (18a-d), and dihydropyrimidinones (22a-i), as apoptotic inducers and inhibitors of phosphatidylinositol-3-kinase α (PI3Kα), with potential anticancer activity. An initial in vitro screening of 60 cancer cell lines identified pyridopyrimidine derivatives 9a-g as promising broad-spectrum anticancer agents, with compound 9e demonstrating the strongest inhibitory activity, particularly against T-47D breast cancer cells. Notably, the antitumor potency of compound 9e surpassed that of Pictilisib, inducing G2-M phase cell cycle arrest and initiating apoptosis through the intrinsic apoptotic pathway. Molecular docking studies further indicated that compound 9e binds to PI3Kα in a similar fashion to the co-crystallized ligand. Moreover, compound 9e exhibited favorable drug-like properties, including compliance with Lipinski's rule and Veber's rule, good solubility, acceptable TPSA, and high gastrointestinal absorption reinforcing its potential as a highly effective anticancer agent.

KIRA6 is an Effective and Versatile Mast Cell Inhibitor of IgE-mediated Activation

Mast cell (MC)-driven allergic diseases are constantly expanding and require the development of novel pharmacological MC stabilizers. Allergen/antigen (Ag)-triggered activation via crosslinking of the high-affinity receptor for IgE (FcεRI) is fundamentally regulated by SRC family kinases, for example, LYN and FYN, exhibiting positive and negative functions. We report that KIRA6, an inhibitor for the endoplasmic reticulum stress sensor IRE1α, suppresses IgE-mediated MC activation by inhibiting both LYN and FYN. KIRA6 attenuates Ag-stimulated early signaling and effector functions such as degranulation and proinflammatory cytokine production/secretion in murine bone marrow-derived MCs. Moreover, Ag-triggered bronchoconstriction in an ex vivo model and IgE-mediated stimulation of human MCs were repressed by KIRA6. The interaction of KIRA6 with three MC-relevant tyrosine kinases, LYN, FYN, and KIT, and the potential of KIRA6 structure as a pharmacophore for the development of respective single-, dual-, or triple-specificity inhibitors, was evaluated by homology modeling and molecular dynamics simulations. We found that KIRA6 particularly strongly binds the inactive state of LYN, FYN, and KIT with comparable affinities. In conclusion, our data suggest that the chemical structure of KIRA6 as a pharmacophore can be further developed to obtain an effective MC stabilizer.

S, Pai KSR, Kini SG. Design of PI3K-mTOR Dual Inhibitors for Ovarian Cancer: Are we on the Right Track?

Ovarian cancer is one of the most familiar kinds of gynecological cancer seen in women. Though it is not as familiar as breast cancer, the survival rate for ovarian cancer is very low when compared with breast cancer. Even after being one among the familiar types, to date, there are no proper treatments available for ovarian cancer. All the treatments that are present currently show a high rate of recurrence after the treatment. Therefore, treating this silent killer from the roots is the need of the hour. PI3K/AKT/m-TOR pathway is one of the pathways that get altered during ovarian cancer. Studies are already going on for the inhibition of PI3K and mTOR separately. Efforts have been made to inhibit either PI3K or mTOR separately earlier. However, due to its side effects and resistance to the treatments available, current studies are based on the inhibition of PI3K and mTOR together. Inhibition of PI3K and mTOR simultaneously reduces the chances of negative feedback, thus decreasing the toxicity. This review contains the evolution of PI3K and mTOR drugs that are approved by the FDA and are in the trials for different cancer types, including ovarian cancer. In this article, how a molecular targeted therapy can be made successful and free from toxicity for treating ovarian cancer is discussed. Therefore, this review paves the way for finding an effective scaffold rather than the clinical part. The scaffold thus selected can be further modified and synthesized in the future as dual PI3K/mTOR inhibitors specifically for OC.

Design, synthesis, molecular modelling and biological evaluation of novel 6-amino-5-cyano-2-thiopyrimidine derivatives as potent anticancer agents against leukemia and apoptotic inducers

Herein, a novel series of 6-amino-5-cyano-2-thiopyrimidines and condensed pyrimidines analogues were prepared. All the synthesized compounds (1a-c, 2a-c, 3a-c, 4a-r and 5a-c) were evaluated for in vitro anticancer activity by the National Cancer Institute (NCI; MD, USA) against 60 cell lines. Compound 1c showed promising anticancer activity and was selected for the five-dose testing. Results demonstrated that compound 1c possessed broad spectrum anti-cancer activity against the nine cancerous subpanels tested with selectivity ratio ranging from 0.7 to 39 at the GI50 level with high selectivity towards leukaemia. Mechanistic studies showed that Compound 1c showed comparable activity to Duvelisib against PI3Kδ (IC50 = 0.0034 and 0.0025 μM, respectively) and arrested cell cycle at the S phase and displayed significant increase in the early and late apoptosis in HL60 and leukaemia SR cells. The necrosis percentage showed a significant increase from 1.13% to 3.41% in compound 1c treated HL60 cells as well as from 1.51% to 4.72% in compound 1c treated leukaemia SR cells. Also, compound 1c triggered apoptosis by activating caspase 3, Bax, P53 and suppressing Bcl2. Moreover, 1c revealed a good safety profile against human normal lung fibroblast cell line (WI-38 cells). Molecular analysis of Duvelisib and compound 1c in PI3K was performed. Finally, these results suggest that 2-thiopyrimidine derivative 1c might serve as a model for designing novel anticancer drugs in the future.

Identification of novel inhibitors targeting PI3Kα via ensemble-based virtual screening method, biological evaluation and molecular dynamics simulation

PIK3CA gene encoding PI3K p110α is one of the most frequently mutated and overexpressed in majority of human cancers. Development of potent and selective novel inhibitors targeting PI3Kα was considered as the most promising approaches for cancer treatment. In this investigation, a virtual screening platform for PI3Kα inhibitors was established by employing machine learning methods, pharmacophore modeling, and molecular docking approaches. 28 potential PI3Kα inhibitors with different scaffolds were selected from the databases with 295,024 compounds. Among the 28 hits, hit15 exhibited the best inhibitory effect against PI3Kα with IC50 value less than 1.0 µM. The molecular dynamics simulation indicated that hit15 could stably bind to the active site of PI3Kα, interact with some residues by hydrophobic, electrostatic and hydrogen bonding interactions, and finally induced PI3Kα active pocket substantial conformation changes. Stable H-bond interactions were formed between hit15 and residues of Lys776, Asp810 and Asp933. The binding free energy of PI3Kα-hit15 was - 65.3 kJ/mol. The free energy decomposition indicated that key residues of Asp805, Ile848 and Ile932 contributed stronger energies to the binding free energy. The above results indicated that hit15 with novel scaffold was a potent PI3Kα inhibitor and considered as a promising candidate for further drug development to treat various cancers with PI3Kα over activated.

Unveiling the role of PIK3R1 in cancer: A comprehensive review of regulatory signaling and therapeutic implications

Phosphoinositide 3-kinase (PI3K) is responsible for phosphorylating phosphoinositides to generate secondary signaling molecules crucial for regulating various cellular processes, including cell growth, survival, and metabolism. The PI3K is a heterodimeric enzyme complex comprising of a catalytic subunit (p110α, p110β, or p110δ) and a regulatory subunit (p85). The binding of the regulatory subunit, p85, with the catalytic subunit, p110, forms an integral component of the PI3K enzyme. PIK3R1 (phosphoinositide-3-kinase regulatory subunit 1) belongs to class IA of the PI3K family. PIK3R1 exhibits structural complexity due to alternative splicing, giving rise to distinct isoforms, prominently p85α and p55α. While the primary p85α isoform comprises multiple domains, including Src homology 3 (SH3) domains, a Breakpoint Cluster Region Homology (BH) domain, and Src homology 2 (SH2) domains (iSH2 and nSH2), the shorter isoform, p55α, lacks certain domains present in p85α. In this review, we will highlight the intricate regulatory mechanisms governing PI3K signaling along with the impact of PIK3R1 alterations on cellular processes. We will further delve into the clinical significance of PIK3R1 mutations in various cancer types and their implications for prognosis and treatment outcomes. Additionally, we will discuss the evolving landscape of targeted therapies aimed at modulating PI3K-associated pathways. Overall, this review will provide insights into the dynamic interplay of PIK3R1 in cancer, fostering advancements in precision medicine and the development of targeted interventions.

Targeting the RAS upstream and downstream signaling pathway for cancer treatment

Cancer often involves the overactivation of RAS/RAF/MEK/ERK (MAPK) and PI3K-Akt-mTOR pathways due to mutations in genes like RAS, RAF, PTEN, and PIK3CA. Various strategies are employed to address the overactivation of these pathways, among which targeted therapy emerges as a promising approach. Directly targeting specific proteins, leads to encouraging results in cancer treatment. For instance, RTK inhibitors such as imatinib and afatinib selectively target these receptors, hindering ligand binding and reducing signaling initiation. These inhibitors have shown potent efficacy against Non-Small Cell Lung Cancer. Other inhibitors, like lonafarnib targeting Farnesyltransferase and GGTI 2418 targeting geranylgeranyl Transferase, disrupt post-translational modifications of proteins. Additionally, inhibition of proteins like SOS, SH2 domain, and Ras demonstrate promising anti-tumor activity both in vivo and in vitro. Targeting downstream components with RAF inhibitors such as vemurafenib, dabrafenib, and sorafenib, along with MEK inhibitors like trametinib and binimetinib, has shown promising outcomes in treating cancers with BRAF-V600E mutations, including myeloma, colorectal, and thyroid cancers. Furthermore, inhibitors of PI3K (e.g., apitolisib, copanlisib), AKT (e.g., ipatasertib, perifosine), and mTOR (e.g., sirolimus, temsirolimus) exhibit promising efficacy against various cancers such as Invasive Breast Cancer, Lymphoma, Neoplasms, and Hematological malignancies. This review offers an overview of small molecule inhibitors targeting specific proteins within the RAS upstream and downstream signaling pathways in cancer.

Tumor antigen presentation and the associated signal transduction during carcinogenesis

Numerous developments have been achieved in the study and treatment of cancer throughout the decades that it has been common. After decades of research, about 100 different kinds of cancer have been found, each with unique subgroups within certain organs. This has significantly expanded our understanding of the illness. A mix of genetic, environmental, and behavioral variables contribute to the complicated and diverse process of cancer formation. Mutations, or changes in the DNA sequence, are crucial to the development of cancer. These mutations have the ability to downregulate the expression and function of Major Histocompatibility Complex class I (MHC I) and MHCII receptors, as well as activate oncogenes and inactivate tumor suppressor genes. Cancer cells use this tactic to avoid being recognized by cytotoxic CD8+T lymphocytes, which causes issues with antigen presentation and processing. This review goes into great length into the PI3K pathway, changes to MHC I, and positive impacts of tsMHC-II on disease-free survival and overall survival and the involvement of dendritic cells (DCs) in different tumor microenvironments. The vital functions that the PI3K pathway and its link to the mTOR pathway are highlighted and difficulties in developing effective cancer targeted therapies and feedback systems has also been mentioned, where resistance mechanisms include RAS-mediated oncogenic changes and active PI3K signalling.

Enzyme Is the Name-Adapter Is the Game

Signaling proteins in eukaryotes usually comprise a catalytic domain coupled to one or several interaction domains, such as SH2 and SH3 domains. An additional class of proteins critically involved in cellular communication are adapter or scaffold proteins, which fulfill their purely non-enzymatic functions by organizing protein-protein interactions. Intriguingly, certain signaling enzymes, e.g., kinases and phosphatases, have been demonstrated to promote particular cellular functions by means of their interaction domains only. In this review, we will refer to such a function as "the adapter function of an enzyme". Though many stories can be told, we will concentrate on several proteins executing critical adapter functions in cells of the immune system, such as Bruton´s tyrosine kinase (BTK), phosphatidylinositol 3-kinase (PI3K), and SH2-containing inositol phosphatase 1 (SHIP1), as well as in cancer cells, such as proteins of the rat sarcoma/extracellular signal-regulated kinase (RAS/ERK) mitogen-activated protein kinase (MAPK) pathway. We will also discuss how these adaptor functions of enzymes determine or even undermine the efficacy of targeted therapy compounds, such as ATP-competitive kinase inhibitors. Thereby, we are highlighting the need to develop pharmacological approaches, such as proteolysis-targeting chimeras (PROTACs), that eliminate the entire protein, and thus both enzymatic and adapter functions of the signaling protein. We also review how genetic knock-out and knock-in approaches can be leveraged to identify adaptor functions of signaling proteins.

PQR309, a dual PI3K/mTOR inhibitor, synergizes with gemcitabine by impairing the GSK-3β and STAT3/HSP60 signaling pathways to treat nasopharyngeal carcinoma

End-stage nasopharyngeal carcinoma (NPC) has unsatisfactory survival. The limited benefit of chemotherapy and the scarcity of targeted drugs are major challenges in NPC. New approaches to treat late-stage NPC are urgently required. In this study, we explored whether the dual PI3K/mTOR inhibitor, PQR309, exerted a favorable antineoplastic effect and sensitized the response to gemcitabine in NPC. We observed that PI3K expression was positive and elevated in 14 NPC cell lines compared with that in normal nasopharygeal cell lines. Patients with NPC with higher PI3K levels displayed poorer prognosis. We subsequently showed that PQR309 alone effectively decreased the viability, invasiveness, and migratory capability of NPC cells and neoplasm development in mice xenograft models, and dose-dependently induced apoptosis. More importantly, PQR309 remarkably strengthened the anti-NPC function of gemcitabine both in vivo and in vitro. Mechanistically, PQR309 sensitized NPC to gemcitabine by increasing caspase pathway-dependent apoptosis, blocking GSK-3β and STAT3/HSP60 signaling, and ablating epithelial-mesenchyme transition. Thus, targeting PI3K/mTOR using PQR309 might represent a treatment option to promote the response to gemcitabine in NPC, and provides a theoretical foundation for the study of targeted drugs combined with chemotherapy for NPC.

Statin-Sensitive Akt1/Src/Caveolin-1 Signaling Enhances Oxidative Stress Resistance in Rhabdomyosarcoma

Identifying the molecular mechanisms underlying radioresistance is a priority for the treatment of RMS, a myogenic tumor accounting for approximately 50% of all pediatric soft tissue sarcomas. We found that irradiation (IR) transiently increased phosphorylation of Akt1, Src, and Cav1 in human RD and RH30 lines. Synthetic inhibition of Akt1 and Src phosphorylation increased ROS levels in all RMS lines, promoting cellular radiosensitization. Accordingly, the elevated activation of the Akt1/Src/Cav1 pathway, as detected in two RD lines characterized by overexpression of a myristoylated Akt1 form (myrAkt1) or Cav1 (RDCav1), was correlated with reduced levels of ROS, higher expression of catalase, and increased radioresistance. We found that treatment with cholesterol-lowering drugs such as lovastatin and simvastatin promoted cell apoptosis in all RMS lines by reducing Akt1 and Cav1 levels and increasing intracellular ROS levels. Combining statins with IR significantly increased DNA damage and cell apoptosis as assessed by γ histone 2AX (γH2AX) staining and FACS analysis. Furthermore, in combination with the chemotherapeutic agent actinomycin D, statins were effective in reducing cell survival through increased apoptosis. Taken together, our findings suggest that the molecularly linked signature formed by Akt1, Src, Cav1, and catalase may represent a prognostic determinant for identifying subgroups of RMS patients with higher probability of recurrence after radiotherapy. Furthermore, statin-induced oxidative stress could represent a treatment option to improve the success of radiotherapy.

K-Ras(V12) differentially affects the three Akt isoforms in lung and pancreatic carcinoma cells and upregulates E-cadherin and NCAM via Akt3

K-Ras is the most frequently mutated Ras variant in pancreatic, colon and non-small cell lung adenocarcinoma. Activating mutations in K-Ras result in increased amounts of active Ras-GTP and subsequently a hyperactivation of effector proteins and downstream signaling pathways. Here, we demonstrate that oncogenic K-Ras(V12) regulates tumor cell migration by activating the phosphatidylinositol 3-kinases (PI3-K)/Akt pathway and induces the expression of E-cadherin and neural cell adhesion molecule (NCAM) by upregulation of Akt3. In vitro interaction and co-precipitation assays identified PI3-Kα as a bona fide effector of active K-Ras4B but not of H-Ras or N-Ras, resulting in enhanced Akt phosphorylation. Moreover, K-Ras(V12)-induced PI3-K/Akt activation enhanced migration in all analyzed cell lines. Interestingly, Western blot analyses with Akt isoform-specific antibodies as well as qPCR studies revealed, that the amount and the activity of Akt3 was markedly increased whereas the amount of Akt1 and Akt2 was downregulated in EGFP-K-Ras(V12)-expressing cell clones. To investigate the functional role of each Akt isoform and a possible crosstalk of the isoforms in more detail, each isoform was stably depleted in PANC-1 pancreatic and H23 lung carcinoma cells. Akt3, the least expressed Akt isoform in most cell lines, is especially upregulated and active in Akt2-depleted cells. Since expression of EGFP-K-Ras(V12) reduced E-cadherin-mediated cell-cell adhesion by induction of polysialylated NCAM, Akt3 was analyzed as regulator of E-cadherin and NCAM. Western blot analyses revealed pronounced reduction of E-cadherin and NCAM in the Akt3-kd cells, whereas Akt1 and Akt2 depletion upregulated E-cadherin, especially in H23 lung carcinoma cells. In summary, we identified oncogenic K-Ras4B as a key regulator of PI3-Kα-Akt signaling and Akt3 as a crucial regulator of K-Ras4B-induced modulation of E-cadherin and NCAM expression and localization.

A combined opposite targeting of p110δ PI3K and RhoA abrogates skin cancer

Malignant melanoma is the most aggressive and deadly skin cancer with an increasing incidence worldwide whereas SCC is the second most common non-melanoma human skin cancer with limited treatment options. Here we show that the development and metastasis of melanoma and SCC cancers can be blocked by a combined opposite targeting of RhoA and p110δ PI3K. We found that a targeted induction of RhoA activity into tumours by deletion of p190RhoGAP-a potent inhibitor of RhoA GTPase-in tumour cells together with adoptive macrophages transfer from δD910A/D910A mice in mice bearing tumours with active RhoA abrogated growth progression of melanoma and SCC tumours. Τhe efficacy of this combined treatment is the same in tumours lacking activating mutations in BRAF and in tumours harbouring the most frequent BRAF(V600E) mutation. Furthermore, the efficiency of this combined treatment is associated with decreased ATX expression in tumour cells and tumour stroma bypassing a positive feedback expression of ATX induced by direct ATX pharmacological inactivation. Together, our findings highlight the importance of targeting cancer cells and macrophages for skin cancer therapy, emerge a reverse link between ATX and RhoA and illustrate the benefit of p110δ PI3K inhibition as a combinatorial regimen for the treatment of skin cancers.

TrkB/BDNF signaling pathway and its small molecular agonists in CNS injury

As one of the most prevalent neurotrophic factors in the central nervous system (CNS), brain-derived neurotrophic factor (BDNF) plays a significant role in CNS injury by binding to its specific receptor Tropomyosin-related kinase receptor B (TrkB). The BDNF/TrkB signaling pathway is crucial for neuronal survival, structural changes, and plasticity. BDNF acts as an axonal growth and extension factor, a pro-survival factor, and a synaptic modulator in the CNS. BDNF also plays an important role in the maintenance and plasticity of neuronal circuits. Several studies have demonstrated the importance of BDNF in the treatment and recovery of neurodegenerative and neurotraumatic disorders. By undertaking in-depth study on the mechanism of BDNF/TrkB function, important novel therapeutic strategies for treating neuropsychiatric disorders have been discovered. In this review, we discuss the expression patterns and mechanisms of the TrkB/BDNF signaling pathway in CNS damage and introduce several intriguing small molecule TrkB receptor agonists produced over the previous several decades.

Regulation of Eukaryotic Translation Initiation Factor 4E as a Potential Anticancer Strategy

Eukaryotic translation initiation factors (eIFs) are highly expressed in cancer cells, especially eIF4E, the central regulatory node driving cancer cell growth and a potential target for anticancer drugs. eIF4E-targeting strategies primarily focus on inhibiting eIF4E synthesis, interfering with eIF4E/eIF4G interactions, and targeting eIF4E phosphorylation and peptide inhibitors. Although some small-molecule inhibitors are in clinical trials, no eIF4E inhibitors are available for clinical use. We provide an overview of the regulatory mechanisms of eIF4E and summarize the progress in developing and discovering eIF4E inhibitor strategies. We propose that interference with eIF4E/eIF4G interactions will provide a new perspective for the design of eIF4E inhibitors and may be a preferred strategy.

The Importance of the Pyrazole Scaffold in the Design of Protein Kinases Inhibitors as Targeted Anticancer Therapies

The altered activation or overexpression of protein kinases (PKs) is a major subject of research in oncology and their inhibition using small molecules, protein kinases inhibitors (PKI) is the best available option for the cure of cancer. The pyrazole ring is extensively employed in the field of medicinal chemistry and drug development strategies, playing a vital role as a fundamental framework in the structure of various PKIs. This scaffold holds major importance and is considered a privileged structure based on its synthetic accessibility, drug-like properties, and its versatile bioisosteric replacement function. It has proven to play a key role in many PKI, such as the inhibitors of Akt, Aurora kinases, MAPK, B-raf, JAK, Bcr-Abl, c-Met, PDGFR, FGFRT, and RET. Of the 74 small molecule PKI approved by the US FDA, 8 contain a pyrazole ring: Avapritinib, Asciminib, Crizotinib, Encorafenib, Erdafitinib, Pralsetinib, Pirtobrutinib, and Ruxolitinib. The focus of this review is on the importance of the unfused pyrazole ring within the clinically tested PKI and on the additional required elements of their chemical structures. Related important pyrazole fused scaffolds like indazole, pyrrolo[1,2-b]pyrazole, pyrazolo[4,3-b]pyridine, pyrazolo[1,5-a]pyrimidine, or pyrazolo[3,4-d]pyrimidine are beyond the subject of this work.

Medicinal Chemistry of Quinazolines as Anticancer Agents Targeting Tyrosine Kinases

Cancer is a large group of diseases that can affect any organ or body tissue due to the abnormal cellular growth with the unknown reasons. Many of the existing chemotherapeutic agents are highly toxic with a low level of selectivity. Additionally, they lead to development of therapeutic resistance. Hence, the development of targeted chemotherapeutic agents with low side effects and high selectivity is required for cancer treatment. Quinazoline is a vital scaffold well-known to be linked with several biological activities. The anticancer activity is one of the prominent biological activities of this scaffold. Several established anticancer quinazolines work by different mechanisms on the various molecular targets. The aim of this review is to present different features of medicinal chemistry as drug design, structure activity relationship, and mode of action of some targeted anticancer quinazoline derivatives. It gives comprehensive attention on the chemotherapeutic activity of quinazolines in the viewpoint of drug discovery and its development. This review provides panoramic view to the medicinal chemists for supporting their efforts to design and synthesize novel quinazolines as targeted chemotherapeutic agents.

Inhibition of the PI3K/AKT/mTOR signaling promotes an M1 macrophage switch by repressing the ATF3-CXCL8 axis in Ewing sarcoma

Ewing sarcomas are aggressive pediatric tumors of bone and soft tissues driven by in frame chromosomal translocations that yield fusion proteins guiding the oncogenic program. Promising alternative strategies to ameliorate current treatments involve inhibition of the PI3K/AKT/mTOR pathway. In this study, we identified the activating transcription factor 3 (ATF3) as an important mediator of the PI3K/AKT/mTOR pathway in Ewing sarcoma cells. ATF3 exerted its pro-tumoral activity through modulation of several chemokine-encoding genes, including CXCL8. The product of CXCL8, IL-8, acts as a pro-inflammatory chemokine critical for cancer progression and metastasis. We found that ATF3/IL-8 axis impacts macrophages populating the surrounding tumor microenvironment by promoting the M2 phenotype. Our study reveals valuable information on the PI3K/AKT/mTOR derived chemokine signaling in Ewing sarcoma cells: by promoting ATF3 and CXCL8 downregulation, inhibition of the PI3K/AKT/mTOR signaling promotes a proinflammatory response leading to upregulation of the protective anti-tumoral M1 macrophages.

Therapeutic Importance of Kaempferol in the Treatment of Cancer through the Modulation of Cell Signalling Pathways

Plant-derived flavonoids are considered natural nontoxic chemo-preventers and have been widely studied for cancer treatment in recent decades. Mostly all flavonoid compounds show significant anti-inflammatory, anticancer and antioxidant properties. Kaempferol (Kmp) is a well-studied compound and exhibits remarkable anticancer and antioxidant potential. Kmp can regulate various cancer-related processes and activities such as cell cycle, oxidative stress, apoptosis, proliferation, metastasis, and angiogenesis. The anti-cancer properties of Kmp primarily occur via modulation of apoptosis, MAPK/ERK1/2, P13K/Akt/mTOR, vascular endothelial growth factor (VEGF) signalling pathways. The anti-cancer property of Kmp has been recognized in several in-vivo and in-vitro studies which also includes numerous cell lines and animal models. This flavonoid possesses toxic activities against only cancer cells and have restricted toxicity on healthy cells. In this review, we present extensive research investigations about the therapeutic potential of Kmp in the management of different types of cancers. The anti-cancer properties of Kmp are discussed by concentration on its capability to target molecular-signalling pathway such as VEGF, STAT, p53, NF-κB and PI3K-AKT signalling pathways. The anti-cancer property of Kmf has gained a lot of attention, but the accurate action mechanism remains unclear. However, this natural compound has a great pharmacological capability and is now considered to be an alternative cancer treatment.

N1-Benzyl Tryptamine Pan-SHIP1/2 Inhibitors: Synthesis and Preliminary Biological Evaluation as Anti-Tumor Agents

Inhibition of phosphatidylinositol 3,4,5-trisphosphate 5-phosphatase (SHIP) with small molecule inhibitors leads to apoptosis in tumor cells. Inhibitors that target both SHIP1 and SHIP2 (pan-SHIP1/2 inhibitors) may have benefits in these areas since paralog compensation is not possible when both SHIP paralogs are being inhibited. A series of tryptamine-based pan-SHIP1/2 inhibitors have been synthesized and evaluated for their ability to inhibit the SHIP paralogs. The most active compounds were also evaluated for their effects on cancer cell lines.

The role of PI3Kγ in the immune system: new insights and translational implications

Over the past two decades, new insights have positioned phosphoinositide 3-kinase-γ (PI3Kγ) as a context-dependent modulator of immunity and inflammation. Recent advances in protein structure determination and drug development have allowed for generation of highly specific PI3Kγ inhibitors, with the first now in clinical trials for several oncology indications. Recently, a monogenic immune disorder caused by PI3Kγ deficiency was discovered in humans and modelled in mice. Human inactivated PI3Kγ syndrome confirms the immunomodulatory roles of PI3Kγ and strengthens newly defined roles of this molecule in modulating inflammatory cytokine release in macrophages. Here, we review the functions of PI3Kγ in the immune system and discuss how our understanding of its potential as a therapeutic target has evolved.

Gentiopicroside targets PAQR3 to activate the PI3K/AKT signaling pathway and ameliorate disordered glucose and lipid metabolism

The obstruction of post-insulin receptor signaling is the main mechanism of insulin-resistant diabetes. Progestin and adipoQ receptor 3 (PAQR3), a key regulator of inflammation and metabolism, can negatively regulate the PI3K/AKT signaling pathway. Here, we report that gentiopicroside (GPS), the main bioactive secoiridoid glycoside of Gentiana manshurica Kitagawa, decreased lipid synthesis and increased glucose utilization in palmitic acid (PA) treated HepG2 cells. Additionally, GPS improved glycolipid metabolism in streptozotocin (STZ) treated high-fat diet (HFD)-induced diabetic mice. Our findings revealed that GPS promoted the activation of the PI3K/AKT axis by facilitating DNA-binding protein 2 (DDB2)-mediated PAQR3 ubiquitinated degradation. Moreover, results of surface plasmon resonance (SPR), microscale thermophoresis (MST) and thermal shift assay (TSA) indicated that GPS directly binds to PAQR3. Results of molecular docking and cellular thermal shift assay (CETSA) revealed that GPS directly bound to the amino acids of the PAQR3 NH₂-terminus including Leu40, Asp42, Glu69, Tyr125 and Ser129, and spatially inhibited the interaction between PAQR3 and the PI3K catalytic subunit (P110α) to restore the PI3K/AKT signaling pathway. In summary, our study identified GPS, which inhibits PAQR3 expression and directly targets PAQR3 to restore insulin signaling pathway, as a potential drug candidate for the treatment of diabetes.

Cell Signaling Pathways That Promote Radioresistance of Cancer Cells

Radiation therapy (RT) is a standard treatment for solid tumors and about 50% of patients with cancer, including pediatric cancer, receive RT. While RT has significantly improved the overall survival and quality of life of cancer patients, its efficacy has still been markedly limited by radioresistance in a significant number of cancer patients (intrinsic or acquired), resulting in failure of the RT control of the disease. Radiation eradicates cancer cells mainly by causing DNA damage. However, radiation also concomitantly activates multiple prosurvival signaling pathways, which include those mediated by ATM, ATR, AKT, ERK, and NF-κB that promote DNA damage checkpoint activation/DNA repair, autophagy induction, and/or inhibition of apoptosis. Furthermore, emerging data support the role of YAP signaling in promoting the intrinsic radioresistance of cancer cells, which occurs through its activation of the transcription of many essential genes that support cell survival, DNA repair, proliferation, and the stemness of cancer stem cells. Together, these signaling pathways protect cancer cells by reducing the magnitude of radiation-induced cytotoxicity and promoting radioresistance. Thus, targeting these prosurvival signaling pathways could potentially improve the radiosensitivity of cancer cells. In this review, we summarize the contribution of these pathways to the radioresistance of cancer cells.

Ursolic Acid Decreases the Proliferation of MCF-7 Cell-Derived Breast Cancer Stem-Like Cells by Modulating the ERK and PI3K/AKT Signaling Pathways

Cancer stem cells are strong drivers of metastasis and cancer relapse, which makes them important therapeutic targets. Ursolic acid (UA), a pentacyclic triterpenoid, has anticancer effects in various types of cancer; however, little is known about its effect on the growth of MCF-7 cell-derived breast cancer stem (BCS)-like cells in estrogen receptor positive breast cancer. In this study, the anticancer activity of UA in MCF-7 cell-derived BCS-like cells and its mechanism of action were evaluated. Furthermore, its inhibitory effects on the proliferation of MCF-7 cell-derived BCS-like cells were compared with that on MCF-7 cells. In MCF-7 cells, UA increased p53 and p21 expression but decreased cyclin D, cyclin E, CDK4, and CDK2 expression to induce cell cycle arrest in the G0/G1 phase. Moreover, UA significantly suppressed migration, invasion, and colony formation in MCF-7 cells, and suppressed mammosphere formation in a concentration- dependent manner. In MCF-7 cell-derived BCS-like cells, UA significantly decreased migration, suppressed p-PI3K, p-AKT, and p-ERK expression, and enhanced p-FoxO1/FoxO3a expression. Accordingly, in MCF-7 cell-derived BCS-like cells, UA suppressed proliferation in part by downregulating ERK and PI3K/AKT signaling pathways. These findings provide the first evidence for the selective effects of UA in BCSs.

Design, synthesis, and biological evaluation of new thieno[2,3-d] pyrimidine derivatives as targeted therapy for PI3K with molecular modelling study

Cancer is one of the most aggressive diseases characterised by abnormal growth and uncontrolled cell division. PI3K is a lipid kinase involved in cancer progression which makes it fruitful target for cancer control. 28 new morpholine based thieno[2,3-d] pyrimidine derivatives were designed and synthesised as anti-PI3K agents maintaining the common pharmacophoric features of several potent PI3K inhibitors. Their antiproliferative activity on NCI 60 cell lines as well as their enzymatic activity against PI3K isoforms were evaluated. Three compounds revealed good cytotoxic activities against breast cancer cell lines, especially T-47D. Compound VIb exhibited the best enzymatic inhibitory activity (72% & 84% on PI3Kβ & PI3Kγ), respectively and good activity on most NCI cell lines especially those with over expressed PI3K. Docking was carried out into PI3K active site which showed comparable binding mode to that of the PI-103 inhibitor. Compound VIb could be optimised to serve as a new chemical entity for discovering new anticancer agents.

A Review of Phosphocreatine 3 Kinase δ Subtype (PI3Kδ) and Its Inhibitors in Malignancy

Most cancer deaths are caused by metastasis. The phosphocreatine 3-kinase (PI3K) family includes the I–III classes, with class I divided into 4 subtypes (α, β, γ, δ); and PI3K signaling participates in the regulatory processes of cell proliferation, differentiation, apoptosis, and glucose transport. Moreover, PI3Ks are modulators of cellular membrane lipids involved in signaling and trafficking events. The PI3Kdelta isoform (PI3Kδ), which is not only specifically expressed in hematopoietic cells, but also in different tumor cell lines, is expressed extensively. The increase in PI3Kδ activity is often associated with a variety of cancers. Currently, the strategy of tumor therapy based on PI3Kδ and its related signaling pathway is developing. Besides its established role in controlling functions in autoimmunity and inflammation, the role of PI3Kδ in tumor and metastasis is not clearly elucidated, with the effects of inhibiting PI3Kδ in several types of tumors also remaining unexplored. In addition, the specific inhibitor of PI3Kδ in tumor progression and metastasis and its underlying mechanism need to be further studied. The purpose of this review is to rationalize the existing functions and mechanisms of PI3Kδ in tumor metastasis and the relationship with hematopoietic cells in cancers as well cross-talking with miRNA, which provides a new theoretical basis and potential therapeutic target for the drug therapy of tumor metastasis.

PI3Kγ Mediates Microglial Proliferation and Cell Viability via ROS

(1) Background: Rapid microglial proliferation contributes to the complex responses of the innate immune system in the brain to various neuroinflammatory stimuli. Here, we investigated the regulatory function of phosphoinositide 3-kinase γ (PI3Kγ) and reactive oxygen species (ROS) for rapid proliferation of murine microglia induced by LPS and ATP. (2) Methods: PI3Kγ knockout mice (PI3Kγ KO), mice expressing catalytically inactive PI3Kγ (PI3Kγ KD) and wild-type mice were assessed for microglial proliferation using an in vivo wound healing assay. Additionally, primary microglia derived from newborn wild-type, PI3Kγ KO and PI3Kγ KD mice were used to analyze PI3Kγ effects on proliferation and cell viability, senescence and cellular and mitochondrial ROS production; the consequences of ROS production for proliferation and cell viability after LPS or ATP stimulation were studied using genetic and pharmacologic approaches. (3) Results: Mice with a loss of lipid kinase activity showed impaired proliferation of microglia. The prerequisite of induced microglial proliferation and cell viability appeared to be PI3Kγ-mediated induction of ROS production. (4) Conclusions: The lipid kinase activity of PI3Kγ plays a crucial role for microglial proliferation and cell viability after acute inflammatory activation.

Acetylation of the Catalytic Lysine Inhibits Kinase Activity in PI3Kδ

Covalent inhibition is a powerful strategy to develop potent and selective small molecule kinase inhibitors. Targeting the conserved catalytic lysine is an attractive method for selective kinase inactivation. We have developed novel, selective inhibitors of phosphoinositide 3-kinase δ (PI3Kδ) which acylate the catalytic lysine, Lys779, using activated esters as the reactive electrophiles. The acylating agents were prepared by adding the activated ester motif to a known selective dihydroisobenzofuran PI3Kδ inhibitor. Three esters were designed, including an acetate ester which was the smallest lysine modification evaluated in this work. Covalent binding to the enzyme was characterized by intact protein mass spectrometry of the PI3Kδ-ester adducts. An enzymatic digest coupled with tandem mass spectrometry identified Lys779 as the covalent binding site, and a biochemical activity assay confirmed that PI3Kδ inhibition was a direct result of covalent lysine acylation. These results indicate that a simple chemical modification such as lysine acetylation is sufficient to inhibit kinase activity. The selectivity of the compounds was evaluated against lipid kinases in cell lysates using a chemoproteomic binding assay. Due to the conserved nature of the catalytic lysine across the kinome, we believe the covalent inhibition strategy presented here could be applicable to a broad range of clinically relevant targets.

Molecular Mechanism Exploration of Potent Fluorinated PI3K Inhibitors with a Triazine Scaffold: Unveiling the Unusual Synergistic Effect of Pyridine-to-Pyrimidine Ring Interconversion and CF3 Defluorination

The phosphatidylinostitol-3-kinase (PI3K)/AKT/mammalian target of rapamycin signaling pathway is a vital regulator of cell proliferation, growth, and survival, which is frequently overactivated in many human cancers. To this effect, PI3K, which is an important mediator of this pathway, has been pinpointed as a crucial target in cancer therapy and hence the importance of PI3K inhibitors. It was recently reported that defluorination and pyridine-to-pyrimidine ring interconversion increase the potency of specific small-molecule inhibitors of PI3K. Compound 4, an inhibitor with the difluorinated pyrimidine motif, was found to be eight times more potent against PI3K than compound 1, an inhibitor with the trifluorinated pyridine motif. This observation presents the need to rationally resolve the differential inhibitory mechanisms exhibited by both compounds. In this present work, we employed multiple computational approaches to investigate and distinguish the binding modes of 1 and 4 in addition to the effects they mediate on the secondary structure of PI3K. Likewise, we evaluated two other derivatives, compounds 2 with the difluorinated pyridine motif and 3 with the trifluorinated pyrimidine motif, to investigate the cooperativity effect between the defluorination of CF₃ and pyridine-to-pyrimidine ring interconversion. Findings revealed that PI3K, upon interaction with 4, exhibited a series of structural changes that favored the binding of the inhibitor at the active-site region. Furthermore, a positive (synergistic) cooperativity effect was observed between CF₃ defluorination and pyridine-to-pyrimidine ring interconversion. Moreover, there was a good correlation between the binding free energy estimated and the biological activity reported experimentally. Energy decomposition analysis revealed that the major contributing force to binding affinity variations between 1 and 4 is the electrostatic energy. Per-residue energy-based hierarchical clustering analysis further identified four hot-spot residues ASP841, TYR867, ASP964, and LYS833 and four warm-spot residues ASP836, SER806, ASP837, and LYS808, which essentially mediate the optimal and higher-affinity binding of compound 4 to PI3K relative to 1. This study therefore provides rational insights into the mechanisms by which 4 exhibited superior PI3K-inhibitory activities over 1, which is vital for future structure-based drug discovery efforts in PI3K targeting.

In vitro reconstitution of Sgk3 activation by phosphatidylinositol 3-phosphate

Serum- and glucocorticoid-regulated kinase 3 (Sgk3) is a serine/threonine protein kinase activated by the phospholipid phosphatidylinositol 3-phosphate (PI3P) downstream of growth factor signaling via class I phosphatidylinositol 3-kinase (PI3K) signaling and by class III PI3K/Vps34-mediated PI3P production on endosomes. Upregulation of Sgk3 activity has recently been linked to a number of human cancers; however, the precise mechanism of activation of Sgk3 is unknown. Here, we use a wide range of cell biological, biochemical, and biophysical techniques, including hydrogen-deuterium exchange mass spectrometry, to investigate the mechanism of activation of Sgk3 by PI3P. We show that Sgk3 is regulated by a combination of phosphorylation and allosteric activation. We demonstrate that binding of Sgk3 to PI3P via its regulatory phox homology (PX) domain induces large conformational changes in Sgk3 associated with its activation and that the PI3P-binding pocket of the PX domain of Sgk3 is sequestered in its inactive conformation. Finally, we reconstitute Sgk3 activation via Vps34-mediated PI3P synthesis on phosphatidylinositol liposomes in vitro. In addition to identifying the mechanism of Sgk3 activation by PI3P, our findings open up potential therapeutic avenues in allosteric inhibitor development to target Sgk3 in cancer.

PIK3R3, part of the regulatory domain of PI3K, is upregulated in sarcoma stem-like cells and promotes invasion, migration, and chemotherapy resistance

To identify drivers of sarcoma cancer stem-like cells (CSCs), we compared gene expression using RNA sequencing between HT1080 fibrosarcoma and SK-LMS-1 leiomyosarcoma spheroids (which are enriched for CSCs) compared with the parent populations. The most overexpressed survival signaling-related gene in spheroids was phosphoinositide-3-kinase regulatory subunit 3 (PIK3R3), a regulatory subunit of PI3K, which functions in tumorigenesis and metastasis. In a human sarcoma microarray, PIK3R3 was also overexpressed by 4.1-fold compared with normal tissues. PIK3R3 inhibition using shRNA in the HT1080, SK-LMS-1, and DDLS8817 dedifferentiated liposarcoma in spheroids and in CD133+ cells (a CSC marker) reduced expression of CD133 and the stem cell factor Nanog and blocked spheroid formation by 61-71%. Mechanistic studies showed that in spheroid cells, PIK3R3 activated AKT and ERK signaling. Inhibition of PIK3R3, AKT, or ERK using shRNA or inhibitors decreased expression of Nanog, spheroid formation by 68-73%, and anchorage-independent growth by 76-91%. PIK3R3 or ERK1/2 inhibition similarly blocked sarcoma spheroid cell migration, invasion, secretion of MMP-2, xenograft invasion into adjacent normal tissue, and chemotherapy resistance. Together, these results show that signaling through the PIK3R3/ERK/Nanog axis promotes sarcoma CSC phenotypes such as migration, invasion, and chemotherapy resistance, and identify PIK3R3 as a potential therapeutic target in sarcoma.

Identification of Potential Kinase Inhibitors within the PI3K/AKT Pathway of Leishmania Species

Leishmaniasis is a public health disease that requires the development of more effective treatments and the identification of novel molecular targets. Since blocking the PI3K/AKT pathway has been successfully studied as an effective anticancer strategy for decades, we examined whether the same approach would also be feasible in Leishmania due to their high amount and diverse set of annotated proteins. Here, we used a best reciprocal hits protocol to identify potential protein kinase homologues in an annotated human PI3K/AKT pathway. We calculated their ligandibility based on available bioactivity data of the reported homologues and modelled their 3D structures to estimate the druggability of their binding pockets. The models were used to run a virtual screening method with molecular docking. We found and studied five protein kinases in five different Leishmania species, which are AKT, CDK, AMPK, mTOR and GSK3 homologues from the studied pathways. The compounds found for different enzymes and species were analysed and suggested as starting point scaffolds for the design of inhibitors. We studied the kinases’ participation in protein–protein interaction networks, and the potential deleterious effects, if inhibited, were supported with the literature. In the case of Leishmania GSK3, an inhibitor of its human counterpart, prioritized by our method, was validated in vitro to test its anti-Leishmania activity and indirectly infer the presence of the enzyme in the parasite. The analysis contributes to improving the knowledge about the presence of similar signalling pathways in Leishmania, as well as the discovery of compounds acting against any of these kinases as potential molecular targets in the parasite.

Therapeutic progression of quinazolines as targeted chemotherapeutic agents

Presently cancer is a grave health issue with predominance beyond restrictions. It can affect any organ of the body. Most of the available chemotherapeutic drugs are highly toxic, not much selective and eventually lead to the development of resistance. Therefore, a target specific palliative approach for the treatment of cancer is required. Remarkable advancements in science have illuminated various molecular pathways responsible for cancer. This has resulted in abundant opportunities to develop targeted anticancer agents. Quinazoline nucleus is a privileged scaffold with significant diversified pharmacological activities. Numerous established anticancer quinazoline derivatives constitute a new class of chemotherapeutic agents which are found to act by inhibiting various protein kinases as well as other molecular targets. A recent update on various quinazoline derivatives acting on different types of molecular targets for the treatment of cancer has been compiled in this review. Brief SAR studies of quinazoline derivatives acting through different mechanisms of action have been highlighted. The comprehensive medicinal chemistry aspects of these agents in this review provide a panoramic view to the biologists as well as medicinal chemists working in this area and would assist them in their efforts to design and synthesize novel quinazoline based anticancer compounds.

Research progress of mTOR inhibitors

Mammalian target of rapamycin (mTOR) is a highly conserved Serine/Threonine (Ser/Thr) protein kinase, which belongs to phosphatidylinositol-3-kinase-related kinase (PIKK) protein family. mTOR exists as two types of protein complex: mTORC1 and mTORC2, which act as central controller regulating processes of cell metabolism, growth, proliferation, survival and autophagy. The mTOR inhibitors block mTOR signaling pathway, producing anti-inflammatory, anti-proliferative, autophagy and apoptosis induction effects, thus mTOR inhibitors are mainly used in cancer therapy. At present, mTOR inhibitors are divided into four categories: Antibiotic allosteric mTOR inhibitors (first generation), ATP-competitive mTOR inhibitors (second generation), mTOR/PI3K dual inhibitors (second generation) and other new mTOR inhibitors (third generation). In this article, these four categories of mTOR inhibitors and their structures, properties and some clinical researches will be introduced. Among them, we focus on the structure of mTOR inhibitors and try to analyze the structure-activity relationship. mTOR inhibitors are classified according to their chemical structure and their contents are introduced systematically. Moreover, some natural products that have direct or indirect mTOR inhibitory activities are introduced together. In this article, we analyzed the target, binding mode and structure-activity relationship of each generation of mTOR inhibitors and proposed two hypothetic scaffolds (the inverted-Y-shape scaffold and the C-shape scaffold) for the second generation of mTOR inhibitors. These findings may provide some help or reference for drug designing, drug modification or the future development of mTOR inhibitor.

Deletion of P110δ promotes the development of myocarditis in ApoE‑deficient mice by increasing mononuclear cell peritoneal infiltration

Phosphoinositide 3-kinase catalytic subunit δ isoform (P110δ) is mainly expressed in white blood cells. It is involved in T and B lymphocyte differentiation, maturation and the neutrophil chemotaxis process. Apolipoprotein E (ApoE) is an arginine‑rich alkaline protein, which is present in plasma chylomicron, low‑density lipoprotein and very low‑density lipoprotein. The present study aimed to determine the effects of P110δ deletion on myocarditis in ApoE‑/‑ mice. A mouse model of ApoE and P110δ double deletion was initially constructed; hematoxylin and eosin (H&E) staining was performed to detect the histological alterations in the mouse myocardium. Systolic and diastolic alterations, and alterations in the left ventricular fractional shortening (LVFS) and left ventricular ejection fraction (LVEF) were examined by electrocardiogram. Blood cell of ApoE and P110δ double mice was used to detect changes in white blood cells and monocytes. Western blotting was used to detect the expression levels of apoptosis‑associated proteins, whereas flow cytometry was used to detect the percentage of apoptosis. Morphological alterations in myocardial cells were observed under a microscope. The results of polymerase chain reaction demonstrated that double deletion mice were successfully constructed. H&E staining revealed that cells in the ApoE‑/‑ mice were spindle‑shaped; however, the nuclei were smaller in the double deletion mice. There was no change in cardiac contraction in normal mice; however, in double deletion mice, the systolic and diastolic contractions were markedly reduced. LVFS and LVEF were decreased compared with in the control group. Blood cell analysis indicated that the content of white blood cells and monocytes in the experimental group was significantly higher than that in the control group. Western blotting demonstrated that the expression levels of apoptotic proteins in double deletion mice were significantly higher compared with in the control group. Flow cytometry revealed that the apoptotic ratio was increased in double deletion mice compared with in the control group (42 vs. 21%). These findings suggested that deletion of P110δ may induce monocyte peritoneal infiltration and increase apoptosis, thus promoting the development of myocarditis.

Novel antiproliferative agents bearing morpholinopyrimidine scaffold as PI3K inhibitors and apoptosis inducers; design, synthesis and molecular docking

Two series of novel morpholinopyrimidine derivatives were synthesized and screened for their in-vitro cytotoxic activity against 60 tumor cell line by the National Cancer Institute, USA. The in-vitro cytotoxic IC₅₀ values for the most active compounds 6e, 6g, and 6l against the most sensitive cell line leukemia SR were estimated (IC₅₀ = 0.76, 13.59, and 4.37 uM, respectively). To investigate their PI3K enzyme inhibition activity, the assay was done on Class IA (α, β, & δ) isoforms. The IC₅₀ values were very promising: compound [6e = 11.73 (α), 6.09 (β), 11.18 (δ)], compound [6g = 8.43 (α), 15.84 (β), 30.62 (δ)], and compound [6l = 13.98 (α), 7.22 (β), 10.94 (δ)], compared to the reference compound LY294002 = 6.28 (α), 4.51 (β), 4.60 (δ) uM, respectively. Moreover, cell cycle analysis and annexin V-FITC staining were done on Leukemia SR, there was arrest at G2/M phase and apoptosis was induced. Finally, docking study was performed to analyze the interactive mode of these derivatives in PI3Kα ATP-binding site. These outcomes proved that compounds 6e, 6g, and 6l are potential leads for further optimization as antileukemic agents.

Using Phosphatidylinositol Phosphorylation as Markers for Hyperglycemic Related Breast Cancer

Studies have suggested that type 2 diabetes (T2D) is associated with a higher incidence of breast cancer and related mortality rates. T2D postmenopausal women have an ~20% increased chance of developing breast cancer, and women with T2D and breast cancer have a 50% increase in mortality compared to breast cancer patients without diabetes. This correlation has been attributed to the general activation of insulin receptor signaling, glucose metabolism, phosphatidylinositol (PI) kinases, and growth pathways. Furthermore, the presence of breast cancer specific PI kinase and/or phosphatase mutations enhance metastatic breast cancer phenotypes. We hypothesized that each of the breast cancer subtypes may have characteristic PI phosphorylation profiles that are changed in T2D conditions. Therefore, we sought to characterize the PI phosphorylation when equilibrated in normal glycemic versus hyperglycemic serum conditions. Our results suggest that hyperglycemia leads to: 1) A reduction in PI3P and PIP3, with increased PI4P that is later converted to PI(3,4)P2 at the cell surface in hormone receptor positive breast cancer; 2) a reduction in PI3P and PI4P with increased PIP3 surface expression in human epidermal growth factor receptor 2-positive (HER2+) breast cancer; and 3) an increase in di- and tri-phosphorylated PIs due to turnover of PI3P in triple negative breast cancer. This study begins to describe some of the crucial changes in PIs that play a role in T2D related breast cancer incidence and metastasis.

Aquaporin 4 Blockade Attenuates Acute Lung Injury Through Inhibition of Th17 Cell Proliferation in Mice

Acute lung injury (ALI) is a syndrome characterized by damage to the alveolar-capillary wall, pulmonary edema and recruitment of inflammatory cells. Previous studies have indicated that aquaporin 4 (AQP4) plays a key role in brain edema formation and resolution. However, the role of AQP4 in the development and progression of ALI is not clear and needs to be resolved. In our current study, mouse ALI was induced by intratracheal instillation of lipopolysaccharide (LPS) at a concentration of 30 mg/kg. For the inhibition of AQP4, 200 mg/kg of TGN-020 (Sigma, USA) was administered intraperitoneally every 6 h starting at 30 min before intratracheal instillation of LPS. The results of the present work indicate, for the first time, that mice treated with the AQP4 inhibitor TGN-020 had attenuated LPS-induced lung injury, reduced proinflammatory cytokine release (including IL-1α, IL-1β, IL-6, TNF-α, IL-23, and IL-17A), and an improved survival rate. Additionally, we found that the attenuated lung injury scores, increased survival rate, and decreased BALF total protein concentration in TGN-020-treated mice were all abrogated by rIL-17A administration. Furthermore, TGN-020 treatment downregulated the phosphorylation of PI3K and Akt, increased the expression of SOCS3, and decreased the expression of p-STAT3 and RORγt. In conclusion, inhibition of AQP4 by TGN-020 has a detectable protective effect against lung tissue injury induced by LPS, and this effect is associated with inhibition of IL-17A through the downregulation of the PI3K/Akt signaling pathway and upregulation of SOCS3 protein.

Downregulation of DLGAP1-Antisense RNA 1 Alleviates Vascular Endothelial Cell Injury Via Activation of the Phosphoinositide 3-kinase/Akt Pathway Results from an Acute Limb Ischemia Rat Model

OBJECTIVE

This study aimed to investigate the effect of long non-coding RNA (lncRNA) DLGAP1 antisense RNA 1 (DLGAP1-AS1) on vascular endothelial cell (VEC) injury via the phosphoinositide 3-kinase (PI3K)/Akt pathway in rat models of acute lower limb ischaemia-reperfusion (I/R).

METHODS

Differentially expressed lncRNAs related to I/R were screened using the gene expression omnibus database. Acute lower limb I/R models were induced in male Wistar rats, in which the regulatory mechanisms of DLGAP1-AS1 silencing were analysed after the treatment of small interfering RNA (siRNA) against DLGAP1-AS1 or an inhibitor of the PI3K/Akt pathway. The relationship between DLGAP1-AS1 and the PI3K/Akt pathway was analysed. The levels of tumour necrosis factor (TNF)-α and vascular cell adhesion molecule-1 (VCAM-1), as well as malondialdehyde (MDA) concentration and creatine kinase (CK) activity, were measured. The number of circulating endothelial cells (CECs) and apoptosis of VECs were identified.

RESULTS

Microarray based analysis indicated that DLGAP1-AS1 was highly expressed in I/R, which was further confirmed by detection of expression in rat models of acute lower limb I/R. Notably, the treatment of siRNA against DLGAP1-AS1 led to the activation of the PI3K/Akt pathway. In response to siRNA against DLGAP1-AS1, the levels of TNF-α and VCAM-1 were decreased, and MDA concentration and CK activity was downregulated. Reduced CEC numbers and suppressed VEC apoptosis were also observed.

CONCLUSION

DLGAP1-AS1 silencing could further suppress the oxidative stress, exert an anti-apoptosis effect, and reduce inflammatory reaction, whereby VEC injury is alleviated by activation of the PI3K/Akt pathway in rats with acute lower limb I/R.

Preclinical Development of PQR514, a Highly Potent PI3K Inhibitor Bearing a Difluoromethyl-Pyrimidine Moiety

The phosphoinositide 3-kinase (PI3K)/mechanistic target of rapamycin (mTOR) pathway is a critical regulator of cell growth and is frequently hyperactivated in cancer. Therefore, PI3K inhibitors represent a valuable asset in cancer therapy. Herein we have developed a novel anticancer agent, the potent pan-PI3K inhibitor PQR514 (4), which is a follow-up compound for the phase-II clinical compound PQR309 (1). Compound 4 has an improved potency both in vitro and in cellular assays with respect to its predecessor compounds. It shows superiority in the suppression of cancer cell proliferation and demonstrates significant antitumor activity in an OVCAR-3 xenograft model at concentrations approximately eight times lower than PQR309 (1). The favorable pharmacokinetic profile and a minimal brain penetration promote PQR514 (4) as an optimized candidate for the treatment of systemic tumors.

Design, Synthesis, and Biological Evaluation of Novel Thienopyrimidine Derivatives as PI3Kα Inhibitors

Three series of novel thienopyrimidine derivatives 9a–l, 15a–l, and 18a–h were designed and synthesized, and their IC₅₀ values against four cancer cell lines HepG-2, A549, PC-3, and MCF-7 were evaluated. Most compounds show moderate cytotoxicity against the tested cancer cell lines. The most promising compound 9a showed moderate activity with IC₅₀ values of 12.32 ± 0.96, 11.30 ± 1.19, 14.69 ± 1.32, and 9.80 ± 0.93 µM, respectively. The inhibitory activities of compounds 9a and 15a against PI3Kα and mTOR kinase were further evaluated. Compound 9a exhibited PI3Kα kinase inhibitory activity with IC₅₀ of 9.47 ± 0.63 µM. In addition, docking studies of compounds 9a and 15a were also investigated.

Expression of Phosphoinositide 3-Kinase p110α and p110β Subunits and PIK3CA Mutation in Patients With Advanced Gastric Carcinoma

Activation of phosphoinositide 3-kinase (PI3K) is pivotal for the activity of the oncogenic PI3K/AKT signaling pathway. This study assessed the expression of 2 PI3K isoform proteins, p110α and p110β, and PIK3CA mutational status in advanced gastric carcinoma (AGC) and their correlation with clinicopathologic factors. Tissue microarray blocks were generated from 99 AGCs and immunohistochemically stained for p110α and p110β. Analysis of mutations in the PIK3CA gene, which encodes p110α, was performed using the PNAClamp PIK3CA Mutation Detection kit. Of the 99 tumors, positivity was seen in 62 (62.6%) for p110α and 97 (98.0%) for p110β with variable intensity and extent of staining. The median H-scores were 40 (range: 0 to 300) for p110α and 180 (range: 0 to 300) for p110β. Isoform p110α was more highly expressed in tumors with a lower pathologic T stage (P=0.035) and TNM stage (P=0.165), while p110β was not significantly associated with clinicopathologic factors. Samples with high p110α expression had a trend toward longer overall survival (OS) although it was not statistically significant (P=0.271), whereas high p110β expression correlated with shorter OS (P=0.016). In addition, p110β was an independent factor for poor prognosis in multivariate analysis for OS. Eight (8.1%) samples had PIK3CA mutations in exon 9. Mutational status at this locus was not significantly correlated with clinicopathologic factors. These results imply that p110β could have a more important role in the progression and aggressiveness of AGC than p110α and has potential as a prognostic biomarker in patients with AGC.

Non-pharmacological management of gestational diabetes: The role of myo-inositol

Gestational diabetes mellitus (GDM) is the most common metabolic disorder occurring in pregnancy. GDM plays an important role in the current diabetes epidemic: exposure to a high glycemic environment during the early stages of development increases the risk of the fetus to develop type two diabetes mellitus (T2DM) in adult life. Various cardiometabolic risk factors are linked to GDM. A thorough knowledge of the risk factors and genes involved in the development of GDM, along with an understanding of the underlying pathophysiological mechanisms are crucial to properly identify patients at risk of developing this condition. There is growing evidence showing that myo-inositol, combined with an appropriate therapeutic regimen for GDM, can provide additional benefits to the patient. The aim of this review is to analyze the role of inositol isomers - especially myo-inositol (MYO-INS) - in the treatment of patients with GDM.