Antitumor activity of ZSTK474, a new phosphatidylinositol 3-kinase inhibitor

1,3,5-Triazine as a promising scaffold in the development of therapeutic agents against breast cancer

1,3,5-Triazine scaffold has garnered considerable interest due to its wide-ranging pharmacological properties, particularly in the field of cancer research. Breast cancer is the most commonly diagnosed cancer among women. Approximately one in eight women will receive a diagnosis of invasive breast cancer during their lifetime. The five-year survival rate for invasive breast cancer is less than 30 %, indicating a need to develop a more effective therapeutic agent targeting breast cancer. This review discusses bioactive 1,3,5-triazines targeting breast cancer cells by the inhibition of different enzymes, which include PI3K, mTOR, EGFR, VEGFR, FAK, CDK, DHFR, DNA topoisomerase, ubiquitin-conjugating enzyme, carbonic anhydrase, and matrix metalloproteinase. The anticancer agent search in some drug discovery programs is based on compound screening for antiproliferative activity. Often, multiple targets contribute to the anticancer effect of 1,3,5-triazines and this approach allows identification of active molecules prior to identification of their targets.

Dissecting the Interaction Fingerprints and Binding Affinity of BYL719 Analogs Targeting PI3Kα

Phosphatidylinositol-3-kinase Alpha (PI3Kα) is a lipid kinase which regulates signaling pathways involved in cell proliferation. Dysregulation of these pathways promotes several human cancers, pushing for the development of anticancer drugs to target PI3Kα. One such medicinal chemistry campaign at Novartis led to the discovery of BYL719 (Piqray, Alpelicib), a PI3Kα inhibitor approved by the FDA in 2019 for treatment of HR+/HER2-advanced breast cancer with a PIK3CA mutation. Structure-based drug design played a key role in compound design and optimization throughout the discovery process. However, further characterization of potency drivers via structural dynamics and energetic analyses can be advantageous for ensuing PI3Kα programs. Here, our goal is to employ various in-silico techniques, including molecular simulations and machine learning, to characterize 14 ligands from the BYL719 analogs and predict their binding affinities. The structural insights from molecular simulations suggest that although the ligand-hinge interaction is the primary driver of ligand stability at the pocket, the R group positioning at C2 or C6 of pyridine/pyrimidine also plays a major role. Binding affinities predicted via thermodynamic integration (TI) are in good agreement with previously reported IC50s. Yet, computationally demanding techniques such as TI might not always be the most efficient approach for affinity prediction, as in our case study, fast high-throughput techniques were capable of classifying compounds as active or inactive, and one docking approach showed accuracy comparable to TI.

Advancements in dual-target inhibitors of PI3K for tumor therapy: Clinical progress, development strategies, prospects

Phosphoinositide 3-kinases (PI3Ks) modify lipids by the phosphorylation of inositol phospholipids at the 3'-OH position, thereby participating in signal transduction and exerting effects on various physiological processes such as cell growth, metabolism, and organism development. PI3K activation also drives cancer cell growth, survival, and metabolism, with genetic dysregulation of this pathway observed in diverse human cancers. Therefore, this target is considered a promising potential therapeutic target for various types of cancer. Currently, several selective PI3K inhibitors and one dual-target PI3K inhibitor have been approved and launched on the market. However, the majority of these inhibitors have faced revocation or voluntary withdrawal of indications due to concerns regarding their adverse effects. This article provides a comprehensive review of the structure and biological functions, and clinical status of PI3K inhibitors, with a specific emphasis on the development strategies and structure-activity relationships of dual-target PI3K inhibitors. The findings offer valuable insights and future directions for the development of highly promising dual-target drugs targeting PI3K.

β-carboline derivative Z86 attenuates colorectal cancer cell proliferation and migration by directly targeting PI3K

Phosphoinositide 3-kinase (PI3Ks) are lipid kinases widely involved in cell proliferation, metastasis and differentiation. Constitutive activation of the PI3K/Akt/mTOR signaling are well confirmed in colorectal cancers (CRCs). In this study, we identified isopropyl 9-ethyl-1-(naphthalen-1-yl)-9 H-pyrido[3,4-b] indole-3-carboxylate (Z86), as a novel PI3Kα inhibitor with the IC50 value of 4.28 µM. The binding of Z86 to PI3Kα was further confirmed with DARTS and CETSA assay. Immunofluorescence analysis and western blotting data demonstrated that Z86 effectively attenuated PI3K/AKT pathway. Z86 caused dramatic proliferation inhibition of CRCs through G0/G1 cycle arrest rather than apoptosis induction. Besides, the migration of CRCs was also relieved by Z86. The present study not only identified Z86 as a novel PI3Kα inhibitor with potent inhibitory efficiency on PI3K-mediated CRCs growth and migration, but also elucidated a reasonable molecular mechanism of Z86 in the Wnt signaling pathway inhibition.

Molecular medicinal insights into scaffold hopping-based drug discovery success

In both academia and the pharmaceutical industry, innovative hypotheses, methodologies and technologies that can shorten the drug research and development, leading to higher success rates, are vital. In this review, we demonstrate how innovative variations of the scaffold-hopping strategy have been used to create new druggable molecular spaces, drugs, clinical candidates, preclinical candidates, and bioactive agents. We also analyze molecular modulations that enabled improvements of the pharmacodynamic (PD), physiochemical, and pharmacokinetic (PK) properties (P3 properties) of the drugs resulting from these scaffold-hopping strategies.

Discovery of novel potent PI3K/mTOR dual-target inhibitors based on scaffold hopping: Design, synthesis, and antiproliferative activity

The PI3K/AKT/mTOR pathway is one of the most common dysregulated signaling cascade responses in human cancers, playing a crucial role in cell proliferation and angiogenesis. Therefore, the development of anticancer drugs targeting the PI3K and mTOR pathways has become a research hotspot in cancer treatment. In this study, the PI3K selective inhibitor GDC-0941 was selected as a lead compound, and 28 thiophenyl-triazine derivatives with aromatic urea structures were synthesized based on scaffold hopping, serving as a novel class of PI3K/mTOR dual inhibitors. The most promising compound Y-2 was obtained through antiproliferative activity evaluation, kinase inhibition, and toxicity assays. The results showed that Y-2 demonstrated potential inhibitory effects on both PI3K kinase and mTOR kinase, with IC50 values of 171.4 and 10.2 nM, respectively. The inhibitory effect of Y-2 on mTOR kinase was 52 times greater than that of the positive drug GDC-0941. Subsequently, the antitumor activity of Y-2 was verified through pharmacological experiments such as AO staining, cell apoptosis, scratch assays, and cell colony formation. The antitumor mechanism of Y-2 was further investigated through JC-1 experiments, real-time quantitative PCR, and Western blot analysis. Based on the above experiments, Y-2 can be identified as a potent PI3K/mTOR dual inhibitor for cancer treatment.

Design and Synthesis of 1,3,5-Triazines or Pyrimidines Containing Dithiocarbamate Moiety as PI3Kα Selective Inhibitors

Recent studies have shown that phosphoinositide 3-kinase (PI3K) plays a vital role in cell division, and it has become a therapeutic target for many cancers. In this paper, some new 1,3,5-triazine or pyrimidine skeleton derivatives containing dithiocarbamate were designed and synthesized based on the reasonable drug design strategy from the previously effective compound 2-(difluoromethyl)-1-[4,6-di(4-morpholinyl)-1,3,5-triazin-2-yl]-1H-benzimidazole (ZSTK-474), in order to get effective selective PI3Kα inhibitors that have not been reported in the literature. In addition, the inhibitory activities of these compounds on PI3Kα and two tumor cell lines in vitro (HCT-116, U87-MG) were evaluated. The representative compound 13 showed a half-maximal inhibitory concentration (IC50) value of 1.2 nM for PI3Kα and an exciting kinase selectivity. Compound 13 displayed strong efficacy in HCT-116 and U87-MG cell lines with IC50 values of 0.83 and 1.25 μM, respectively. In addition, compound 13 induced obvious tumor regression in the U87-MG cell line xenografts mouse model, with no obvious signs of toxicity after intraperitoneal injection at a dose of 40 mg/kg. Compound 13 can be an effective selective inhibitor of PI3Kα, and it provides patients with an opportunity to avoid the side effects related to the wider inhibition of the class I PI3K family.

Deciphering the Biology of Circulating Tumor Cells through Single-Cell RNA Sequencing: Implications for Precision Medicine in Cancer

Circulating tumor cells (CTCs) hold unique biological characteristics that directly involve them in hematogenous dissemination. Studying CTCs systematically is technically challenging due to their extreme rarity and heterogeneity and the lack of specific markers to specify metastasis-initiating CTCs. With cutting-edge technology, single-cell RNA sequencing (scRNA-seq) provides insights into the biology of metastatic processes driven by CTCs. Transcriptomics analysis of single CTCs can decipher tumor heterogeneity and phenotypic plasticity for exploring promising novel therapeutic targets. The integrated approach provides a perspective on the mechanisms underlying tumor development and interrogates CTCs interactions with other blood cell types, particularly those of the immune system. This review aims to comprehensively describe the current study on CTC transcriptomic analysis through scRNA-seq technology. We emphasize the workflow for scRNA-seq analysis of CTCs, including enrichment, single cell isolation, and bioinformatic tools applied for this purpose. Furthermore, we elucidated the translational knowledge from the transcriptomic profile of individual CTCs and the biology of cancer metastasis for developing effective therapeutics through targeting key pathways in CTCs.

The regulation of PTEN: Novel insights into functions as cancer biomarkers and therapeutic targets

This review summarizes the implications of the primary tumor suppressor protein phosphatase and tensin homolog (PTEN) in aggressive cancer development. PTEN interacts with other cellular proteins or factors suggesting the existence of an intricate molecular network that regulates their oncogenic function. Accumulating evidence has shown that PTEN exists and plays a role in the cytoplasmic organelles and in the nucleus. PTEN blocks phosphoinositide 3-kinases (PI3K)-protein kinase B-mammalian target of rapamycin signaling pathway by dephosphorylating phosphatidylinositol (PI)-3,4,5-triphosphate to PI-4,5-bisphosphate thus counteracting PI3K function. Studies have shown that PTEN expression is tightly regulated at transcriptional, posttranscriptional, and posttranslational levels (including protein-protein interactions and posttranslational modifications). Despite recent advances in PTEN research, the regulation and function of the PTEN gene remain largely unknown. How mutation or loss of specific exons in the PTEN gene occurs and involves in cancer development is not clear. This review illustrates the regulatory mechanisms of PTEN expression and discusses how PTEN participates in tumor development and/or suppression. Future prospects for the clinical applications are also highlighted.

Membrane-active substituted triazines as antibacterial agents against Staphylococcus aureus with potential for low drug resistance and broad activity

A library of new naphthalimide-triazine analogues was synthesized as broad-spectrum antibacterial agents to overcome drug resistance. Bioactivity assay reveals that derivative 8e, with benzylamine in its structure, exhibits strong antibacterial properties against multi-drug resistance Staphylococcus aureus at a concentration of 1.56 μg/ml. It was also found to be better than chloromycin and amoxicillin. The active compound 8e efficiently inhibits the development of drug resistance within 11 passages. In addition, compound 8e inhibits the formation of biofilms in S. aureus and acts rapidly in bactericidal efficacy. Furthermore, mechanistic studies reveal that compound 8e effectively destroys the cytoplasmic membrane of bacteria, leading to leakage of intercellular protein content and loss in metabolic activity. Compound 8e binds to HSA readily with a binding constant of 1.32 × 10⁵ M^-1, indicating that the compound could be delivered to the target site effectively. Compound 8e can also form a supramolecular complex with DNA to obstruct DNA replications. These results suggest that analogue 8e could be further developed as a potential antibacterial agent. Furthermore, the cytotoxicity of all the synthesized compounds was evaluated against 60 human cancer cell lines to test their potential for anticancer agents.

The lysosomal LAMTOR / Ragulator complex is essential for nutrient homeostasis in brown adipose tissue

OBJECTIVE

In brown adipose tissue (iBAT), the balance between lipid/glucose uptake and lipolysis is tightly regulated by insulin signaling. Downstream of the insulin receptor, PDK1 and mTORC2 phosphorylate AKT, which activates glucose uptake and lysosomal mTORC1 signaling. The latter requires the late endosomal/lysosomal adaptor and MAPK and mTOR activator (LAMTOR/Ragulator) complex, which serves to translate the nutrient status of the cell to the respective kinase. However, the role of LAMTOR in metabolically active iBAT has been elusive.

METHODS

Using an AdipoqCRE-transgenic mouse line, we deleted LAMTOR2 (and thereby the entire LAMTOR complex) in adipose tissue (LT2 AKO). To examine the metabolic consequences, we performed metabolic and biochemical studies in iBAT isolated from mice housed at different temperatures (30 °C, room temperature and 5 °C), after insulin treatment, or in fasted and refed condition. For mechanistic studies, mouse embryonic fibroblasts (MEFs) lacking LAMTOR 2 were analyzed.

RESULTS

Deletion of the LAMTOR complex in mouse adipocytes resulted in insulin-independent AKT hyperphosphorylation in iBAT, causing increased glucose and fatty acid uptake, which led to massively enlarged lipid droplets. As LAMTOR2 was essential for the upregulation of de novo lipogenesis, LAMTOR2 deficiency triggered exogenous glucose storage as glycogen in iBAT. These effects are cell autonomous, since AKT hyperphosphorylation was abrogated by PI3K inhibition or by deletion of the mTORC2 component Rictor in LAMTOR2-deficient MEFs.

CONCLUSIONS

We identified a homeostatic circuit for the maintenance of iBAT metabolism that links the LAMTOR-mTORC1 pathway to PI3K-mTORC2-AKT signaling downstream of the insulin receptor.

Subtype-selective induction of apoptosis in translocation-related sarcoma cells induced by PUMA and BIM upon treatment with pan-PI3K inhibitors

Translocation-related sarcomas (TRSs) harbor an oncogenic fusion gene generated by chromosome translocation and account for approximately one-third of all sarcomas; however, effective targeted therapies have yet to be established. We previously reported that a pan-phosphatidylinositol 3-kinase (PI3K) inhibitor, ZSTK474, was effective for the treatment of sarcomas in a phase I clinical trial. We also demonstrated the efficacy of ZSTK474 in a preclinical model, particularly in cell lines from synovial sarcoma (SS), Ewing's sarcoma (ES) and alveolar rhabdomyosarcoma (ARMS), all of which harbor chromosomal translocations. ZSTK474 selectively induced apoptosis in all these sarcoma cell lines, although the precise mechanism underlying the induction of apoptosis remained unclear. In the present study, we aimed to determine the antitumor effect of PI3K inhibitors, particularly with regards to the induction of apoptosis, against various TRS subtypes using cell lines and patient-derived cells (PDCs). All of the cell lines derived from SS (six), ES (two) and ARMS (one) underwent apoptosis accompanied by the cleavage of poly-(ADP-ribose) polymerase (PARP) and the loss of mitochondrial membrane potential. We also observed apoptotic progression in PDCs from SS, ES and clear cell sarcoma (CCS). Transcriptional analyses revealed that PI3K inhibitors triggered the induction of PUMA and BIM and the knockdown of these genes by RNA interference efficiently suppressed apoptosis, suggesting their functional involvement in the progression of apoptosis. In contrast, TRS-derived cell lines/PDCs from alveolar soft part sarcoma (ASPS), CIC-DUX4 sarcoma and dermatofibrosarcoma protuberans failed to undergo apoptosis nor induce PUMA and BIM expression, as well as cell lines derived from non-TRSs and carcinomas. Thus, we conclude that PI3K inhibitors induce apoptosis in selective TRSs such as ES and SS via the induction of PUMA and BIM and the subsequent loss of mitochondrial membrane potential. This represents proof of concept for PI3K-targeted therapy, particularly such TRS patients.

Discovery of Novel PI3Kδ Inhibitors Based on the p110δ Crystal Structure

PI3Kδ is a key mediator of B-cell receptor signaling and plays an important role in the pathogenesis of certain hematological malignancies, such as chronic lymphocytic leukemia. Idelalisib, which targets PI3Kδ specifically, is the first approved PI3K inhibitor for cancer therapy. Recently, we carried out virtual screening, cell-based assays, adapta kinase assays, and molecular dynamic analysis to discover novel PI3Kδ inhibitors and identified NSC348884 as a lead PI3Kδ inhibitor. NSC348884 had an excellent docking score, potent PI3Kδ-inhibitory activity, antitumor effects on various cancer cell lines, and a favorable binding mode with the active site of PI3Kδ. Moreover, through the structural modification of NSC348884, we further discovered comp#1, which forms H-bonds with both Val828 and Lys779 in the ATP binding pocket of PI3Kδ, with a more favorable conformation binding to PI3Kδ. In addition, we found that N¹, N¹, N²-trimethyl-N²-((6-methyl-1H-benzo[d]imidazol-2-yl) methyl) ethane-1,2-diamine might be a potential scaffold structure. Thus, the result of this study provides a far more efficient approach for discovering novel inhibitors targeting PI3Kδ.

Spautin-1 inhibits mitochondrial complex I and leads to suppression of the unfolded protein response and cell survival during glucose starvation

The unfolded protein response (UPR) is an adaptive stress response pathway that is essential for cancer cell survival under endoplasmic reticulum stress such as during glucose starvation. In this study, we identified spautin-1, an autophagy inhibitor that suppresses ubiquitin-specific peptidase 10 (USP10) and USP13, as a novel UPR inhibitor under glucose starvation conditions. Spautin-1 prevented the induction of UPR-associated proteins, including glucose-regulated protein 78, activating transcription factor 4, and a splicing variant of x-box-binding protein-1, and showed preferential cytotoxicity in glucose-starved cancer cells. However, USP10 and USP13 silencing and treatment with other autophagy inhibitors failed to result in UPR inhibition and preferential cytotoxicity during glucose starvation. Using transcriptome and chemosensitivity-based COMPARE analyses, we identified a similarity between spautin-1 and mitochondrial complex I inhibitors and found that spautin-1 suppressed the activity of complex I extracted from isolated mitochondria. Our results indicated that spautin-1 may represent an attractive mitochondria-targeted seed compound that inhibits the UPR and cancer cell survival during glucose starvation.

Structure-antitumor activity relationship of hybrid acetogenins focusing on connecting groups between heterocycles and the linker moiety

We studied hybrid molecules of annonaceous acetogenins and mitochondrial complex I-inhibiting insecticides to develop a novel anticancer agent. A structure–antitumor activity relationship study focusing on the connecting groups between the heterocycles and the linker moiety bearing the tetrahydrofuran moiety was conducted. Eleven hybrid acetogenins with 1-methylpyrazole instead of γ-lactone were synthesized and their growth inhibitory activities against 39 human cancer cell lines were evaluated. The nitrogen atom at the 2′-position of the linker moiety was essential for inhibiting cancer growth. The 1-methylpyrazole-5-sulfonamide analog showed potent growth inhibition of NCI-H23, a human lung cancer cell line, in a xenograft mouse assay without critical toxicity. Hence, the results of this study may pave the way for the development of novel anticancer agents, with both selective and broad anticancer activities.

The in vivo active 1-methylpyrazole-5-sulfonamide analog of acetogenins was obtained by the structure–antitumor activity relationship, focusing on the connecting groups between the heterocycle and the linker.

Identification of NVP-CLR457 as an Orally Bioavailable Non-CNS-Penetrant pan-Class IA Phosphoinositol-3-Kinase Inhibitor

Balanced pan-class I phosphoinositide 3-kinase inhibition as an approach to cancer treatment offers the prospect of treating a broad range of tumor types and/or a way to achieve greater efficacy with a single inhibitor. Taking buparlisib as the starting point, the balanced pan-class I PI3K inhibitor 40 (NVP-CLR457) was identified with what was considered to be a best-in-class profile. Key to the optimization to achieve this profile was eliminating a microtubule stabilizing off-target activity, balancing the pan-class I PI3K inhibition profile, minimizing CNS penetration, and developing an amorphous solid dispersion formulation. A rationale for the poor tolerability profile of 40 in a clinical study is discussed.

Gramicidin A accumulates in mitochondria, reduces ATP levels, induces mitophagy, and inhibits cancer cell growth

Here we revealed the spatiotemporal behavior of gramicidin A in cancer cells. Gramicidin A depolarizes both the plasma and mitochondrial membranes, inhibits ATP synthesis, and induces mitophagy, thereby causing potent inhibition of cell growth.

Targeting Phosphoinositide 3-Kinase - Five Decades of Chemical Space Exploration

Phosphoinositide 3-kinase (PI3K) plays a key role in a plethora of physiologic processes and controls cell growth, metabolism, immunity, cardiovascular and neurological function, and more. The discovery of wort-mannin as the first potent PI3K inhibitor (PI3Ki) in the 1990s provided rapid identification of PI3K-dependent processes, which drove the discovery of the PI3K/protein kinase B (PKB/Akt)/target of rapamycin (mTOR) pathway. Genetic mouse models and first PI3K isoform-specific inhibitors pinpointed putative therapeutic applications. The recognition of PI3K as target for cancer therapy drove subsequently drug development. Here we provide a brief journey through the emerging roles of PI3K to the development of preclinical and clinical PI3Ki candidates.

Identification of Dihydroorotate Dehydrogenase Inhibitors─Indoluidins─That Inhibit Cancer Cell Growth

Dihydroorotate dehydrogenase (DHODH) catalyzes the rate-limiting step in de novo pyrimidine biosynthesis and is a promising cancer treatment target. This study reports the identification of indoluidin D and its derivatives as inhibitors of DHODH. Cell-based phenotypic screening revealed that indoluidin D promoted myeloid differentiation and inhibited the proliferation of acute promyelocytic leukemia HL-60 cells. Indoluidin D also suppressed cell growth in various other types of cancer cells. Cancer cell sensitivity profiling with JFCR39 and proteomic profiling with ChemProteoBase revealed that indoluidin D is a DHODH inhibitor. Indoluidin D inhibited human DHODH activity in vitro; the DHODH reaction product orotic acid rescued indoluidin D-induced cell differentiation. We synthesized several indoluidin D diastereomer derivatives and demonstrated that stereochemistry was vital to their molecular activity. The indoluidin D derivative indoluidin E showed similar activity to its parent compound and suppressed tumor growth in a murine lung cancer xenograft model. Hence, indoluidin D and its derivatives selectively inhibit DHODH and suppress cancer cell growth.

Structure-Activity Relationships of Thiophene Carboxamide Annonaceous Acetogenin Analogs: Shortening the Alkyl Chain in the Tail Part Significantly Affects Their Growth Inhibitory Activity against Human Cancer Cell Lines

In a previous study, we found that the thiophene carboxamide solamin analog, which is a mono-tetrahydrofuran annonaceous acetogenin, showed potent antitumor activity through the inhibition of mitochondrial complex I. In this study, we synthesized analogs with short alkyl chains instead of the n-dodecyl group in the tail part. We evaluated their growth inhibitory activities against human cancer cell lines. We found that the alkyl chain in the tail part plays an essential role in their activity.

Chemical and Structural Strategies to Selectively Target mTOR Kinase

Dysregulation of the mechanistic target of rapamycin (mTOR) pathway is implicated in cancer and neurological disorder, which identifies mTOR inhibition as promising strategy for the treatment of a variety of human disorders. First-generation mTOR inhibitors include rapamycin and its analogues (rapalogs) which act as allosteric inhibitors of TORC1. Structurally unrelated, ATP-competitive inhibitors that directly target the mTOR catalytic site inhibit both TORC1 and TORC2. Here, we review investigations of chemical scaffolds explored for the development of highly selective ATP-competitive mTOR kinase inhibitors (TORKi). Extensive medicinal chemistry campaigns allowed to overcome challenges related to structural similarity between mTOR and the phosphoinositide 3-kinase (PI3K) family. A broad region of chemical space is covered by TORKi. Here, the investigation of chemical substitutions and physicochemical properties has shed light on the compounds' ability to cross the blood brain barrier (BBB). This work provides insights supporting the optimization of TORKi for the treatment of cancer and central nervous system disorders.

Cancer immunotherapy with PI3K and PD-1 dual-blockade via optimal modulation of T cell activation signal

Background

Immune checkpoint blockade (ICB) induces durable clinical responses in patients with various types of cancer. However, its limited clinical efficacy requires the development of better approaches. In addition to immune checkpoint molecules, tumor-infiltrating immunosuppressive cells including regulatory T cells (Tregs) play crucial roles in the immune suppressive tumor microenvironment. While phosphatidylinositol 3-kinase (PI3K) inhibition as a Treg-targeted treatment has been implicated in animal models, its effects on human Tregs and on the potential impairment of effector T cells are required to be clarified for successful cancer immunotherapy.

Methods

The impact of a selective-PI3K inhibitor ZSTK474 with or without anti-programmed cell death 1 (PD-1) monoclonal antibody on Tregs and CD8⁺ T cells were examined with in vivo animal models and in vitro experiments with antigen specific and non-specific fashions using peripheral blood from healthy individuals and cancer patients. Phenotypes and functions of Tregs and effector T cells were examined with comprehensive gene and protein expression assays.

Results

Improved antitumor effects by the PI3K inhibitor in combination with ICB, particularly PD-1 blockade, were observed in mice and humans. Although administration of the PI3K inhibitor at higher doses impaired activation of CD8⁺ T cells as well as Tregs, the optimization (doses and timing) of this combination treatment selectively decreased intratumoral Tregs, resulting in increased tumor antigen-specific CD8⁺ T cells in the treated mice. Moreover, on the administration of the PI3K inhibitor with the optimal dose for selectively deleting Tregs, PI3K signaling was inhibited not only in Tregs but also in activated CD8⁺ T cells, leading to the enhanced generation of tumor antigen-specific memory CD8⁺ T cells which contributed to durable antitumor immunity. These opposing outcomes between Tregs and CD8⁺ T cells were attributed to the high degree of dependence on T cell signaling in the former but not in the latter.

Conclusions

PI3K inhibitor in the combination with ICB with the optimized protocol fine-tuned T cell activation signaling for antitumor immunity via decreasing Tregs and optimizing memory CD8⁺ T cell responses, illustrating a promising combination therapy.

Small molecules in targeted cancer therapy: advances, challenges, and future perspectives

Due to the advantages in efficacy and safety compared with traditional chemotherapy drugs, targeted therapeutic drugs have become mainstream cancer treatments. Since the first tyrosine kinase inhibitor imatinib was approved to enter the market by the US Food and Drug Administration (FDA) in 2001, an increasing number of small-molecule targeted drugs have been developed for the treatment of malignancies. By December 2020, 89 small-molecule targeted antitumor drugs have been approved by the US FDA and the National Medical Products Administration (NMPA) of China. Despite great progress, small-molecule targeted anti-cancer drugs still face many challenges, such as a low response rate and drug resistance. To better promote the development of targeted anti-cancer drugs, we conducted a comprehensive review of small-molecule targeted anti-cancer drugs according to the target classification. We present all the approved drugs as well as important drug candidates in clinical trials for each target, discuss the current challenges, and provide insights and perspectives for the research and development of anti-cancer drugs.

The PI3K/Akt/mTOR signaling pathway in gastric cancer; from oncogenic variations to the possibilities for pharmacologic interventions

Genetic and epigenetic alterations have been under concentrated investigations for many years in order to unearth the molecules regulating human cancer pathogenesis. However, the identification of a wide range of dysregulated genes and their protein products has raised a question regarding how the results of this large collection of alterations could converge into a formation of one malignancy. The answer may be found in the signaling cascades that regulate the survival and metabolism of the cells. Aberrancies of each participant molecule of such cascades may well result in augmented viability and unlimited proliferation of cancer cells. Among various signaling pathways, the phosphatidylinositol-3-kinase (PI3K) axis has been shown to be activated in about one-third of human cancers. One of the malignancies that is mostly affected by this axis is gastric cancer (GC), one of the most fatal cancers worldwide. In the present review, we aimed to illustrate the significance of the PI3K/Akt/mTOR axis in the pathogenesis of GC and also provided a wide perspective about the application of the inhibitors of this axis in the therapeutic strategies of this malignancy.

The Role of mTOR Signaling as a Therapeutic Target in Cancer

The aim of this review was to summarize current available information about the role of phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling in cancer as a potential target for new therapy options. The mTOR and PI3K/AKT/mTORC1 (mTOR complex 1) signaling are critical for the regulation of many fundamental cell processes including protein synthesis, cell growth, metabolism, survival, catabolism, and autophagy, and deregulated mTOR signaling is implicated in cancer, metabolic dysregulation, and the aging process. In this review, we summarize the information about the structure and function of the mTOR pathway and discuss the mechanisms of its deregulation in human cancers including genetic alterations of PI3K/AKT/mTOR pathway components. We also present recent data regarding the PI3K/AKT/mTOR inhibitors in clinical studies and the treatment of cancer, as well the attendant problems of resistance and adverse effects.

Discovery of novel 1,3,5-triazine derivatives as potent inhibitor of cervical cancer via dual inhibition of PI3K/mTOR

This study describes the synthesis of novel 1,3,5-triazine derivatives as potent inhibitors of cervical cancer. The compounds were initially tested for inhibition of PI3K/mTOR, where they showed significant inhibitory activity. The top-ranking molecule (compound 6 h) was further tested against class I PI3K isoforms, such as PI3Kα, PI3Kβ, PI3Kγ and PI3Kδ, where it showed the most significant activity against PI3Kα. Compound 6 h was then tested for anti-cancer activity against triple-negative breast cancer cells (MDA-MB321), human breast cancer cells (MCF-7), human cervical cancer cells (HeLa) and human liver cancer cells (HepG2), and it showed the greatest potency against HeLa cells. The effects of compound 6 h were further evaluated against the HeLa cells, where it showed significant attenuation of cell viability by inducing cell cycle arrest in the G1 phase. Compound 6 h induced apoptosis and reduced migration and invasion of HeLa cells. Western blotting analysis showed that 6 h inhibited PI3K and mTOR with positive modulation of Bcl-2 and Bax levels in HeLa cells. The effects of compound 6 h were also investigated in a tumour xenograft mouse model, where it showed reduction of tumour volume and weight. It also inhibited the PI3K/Akt/mTOR signalling cascade in xenograft tumour tissues, as evidenced by western blotting analysis. The results of the present study suggest the possible utility of the designed 1,3,5-triazine derivative as a potent inhibitor of cervical cancer.

Diorganyl Diselenides and Iron(III) Chloride Drive the Regio- and Stereoselectivity in the Selenation of Ynamides

We report here our results on the application of ynamides as substrates in the reactions with diorganyl dichalcogenides and iron(III) chloride to give selectively three different types of compounds: E-α-chloro-β-(organoselenyl)enamides, 4-(organochalcogenyl)oxazolones, and vinyl tosylates. The results reveal that the selectivity in the formation of products was obtained by controlling the functional groups directly bonded to the nitrogen atom of the ynamides. Thus, α-chloro-β-(organoselenyl) enamide derivatives were exclusively obtained when the TsN- and MsN-ynamides were treated with a mixture of diorganyl diselenides (1.0 equiv) and FeCl₃ (3.0 equiv) in dichloroethane (DCE, 3 mL), at room temperature. The 4-(organochalcogenyl)oxazolones were selectively obtained with ynamides having an ester group, directly bonded to the nitrogen atom, upon treatment with a solution of FeCl₃ (1.5 equiv) and diorganyl dichalcogenides (1.0 equiv) in dichloromethane (3 mL) at room temperature. Finally, vinyl tosylates were obtained from ynamides having an ester group, directly bonded to the nitrogen atom, by reaction with p-toluenesulfonic acid. We also studied the application of the prepared compounds as substrates for Suzuki and Sonogashira cross-coupling reactions.

Screening of a Panel of Low Molecular Weight Compounds That Inhibit Synovial Fibroblast Invasion in Rheumatoid Arthritis

Increased invasion of synovial fibroblasts and their involvement in cartilage damage are characteristic phenotypes of rheumatoid arthritis (RA). To identify low molecular weight compounds that suppress synovial fibroblast invasion, a panel of inhibitors (n = 330) was initially screened using a real-time cell analysis system for human synovial fibroblasts that were enzymatically isolated from surgical samples of RA patients. To evaluate the effects of the inhibitors identified in the screen, synovial fibroblast migration was measured using a wound-healing assay, and phosphorylation of intracellular signaling molecules was determined by immunoblots. Several candidate inhibitors were identified in the screen, including inhibitors against platelet-derived growth factor receptor (PDGFR), Akt, PI3K, and glycogen kinase synthetase 3 (GSK-3). These inhibitors strongly suppressed synovial fibroblast migration after 72 h and downregulated phosphorylation of Akt (Ser⁴⁷³) at 48 h. When the inhibitors were removed from the culture conditions, both migration and phosphorylated Akt (Ser⁴⁷³) levels were restored. Furthermore, all the categories of inhibitors except for PDGFR inhibitor IV decreased cell proliferation as well as IL-6 production in synovial fibroblasts. Interestingly, GSK-3 inhibitors increased anti-inflammatory cytokine IL-10 production but suppressed IL-23 production from LPS-primed macrophages obtained from healthy donors. In conclusion, blocking PDGFR, PI3K, or GSK-3 could have therapeutic value as an RA treatment that targets the invasion/migration of synovial fibroblasts.

Discovery and Development of SPR519 as a Potent, Selective, and Orally Bioavailable Inhibitor of PI3Kα and mTOR Kinases for the Treatment of Solid Tumors

Herein, we report the identification and preclinical profile of a lead compound 10, (SPR519) as an equally potent dual inhibitor of PI3Kα and mTOR kinases. SPR519 exhibits an EC₅₀ of low sub-micromolar range among various tested cancer cell lines such as A2780 (0.23 μM), PC3 (0.48 μM), and SKOV3 (0.50 μM). When administrated orally, it shows a considerably high plasma exposure (area under curve: 26,858 nM/h at 1 mg/kg) in mice. Moreover, it is found to be safe in animals with a dose of 30 mg/kg BID for 12 days in the dose tolerance study. SPR519 did not show any CYP or hERG liability. The identified lead compound demonstrates significant efficacy and bioavailability in ovarian and colon cancer xenograft models when evaluated for dose-ranging efficacy studies, at a dose as low as 2.5 mg/kg.

IPM712, a vanillin derivative as potential antitumor agents, displays better antitumor activity in colorectal cancers cell lines

Colorectal cancer (CRC), a major health threat in the world, ranks third in incidence and second in mortality among cancers. Chemotherapy, an important treatment for colorectal cancer, have be limited in the clinic due to the resistance and side effect. Studies have shown that PI3K-related regulatory pathways play a colossal role in colorectal cancer. Therefore, it is a good strategy to find a new drug which works by affecting the PI3K signaling pathway. In this paper, we obtained a new vanillin derivative (IPM712) by modifying the structure of IPM711 and tested its anticancer activity in vitro and toxicity in vivo. Results showed that IPM712 has a better anticancer activity than 5-Fu in HCT116 and SW480 cell lines. Furthermore, IPM712 can inhibit cell proliferation, migration and induce the apoptosis by affecting PI3K-related protein expression. Acute toxicity experiments show that IPM712 has no significant toxicity at therapeutic concentrations. Based on these results, IPM712 is a promising anticancer drug candidate for human colorectal cancer therapy.

In Vitro and In Vivo Antimetastatic Effects of ZSTK474 on Prostate Cancer DU145 Cells

BACKGROUND

The lethality of prostate cancer is mainly due to metastasis. Inhibition of metastasis is expected to be a promising approach for prostate cancer therapy. Phosphatidylinositol 3-kinase (PI3K)/Akt pathway is reported to be closely involved in cell growth, migration, etc. Objective: The study investigated the antimetastatic activities of pan-PI3K inhibitor ZSTK474 on DU145 cells.

METHODS

1. The In vitro effect of ZSTK474 on the migration, invasion and adhesion of DU145 cells was determined with Transwell migration assay and wound healing assay, Tranwell invasion assay and adhesion assay, respectively. 2. In vitro effect of ZSTK474 on the signal proteins in DU145 cells was determined with Western blot analysis and ELISA. 3. Moreover, the In vivo antimetastatic effect of ZSTK474 was evaluated with MicroCT and histology analysis.

RESULTS

ZSTK474 potently attenuated the capability of migration, invasion and adhesion of DU145 cells, negatively regulated Girdin, Integrinβ1 and matrix metalloproteinases (MMPs). In addition, the expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF), which are known to be related to angiogenesis and metastasis, was also inhibited. Oral administration of ZSTK474 (200 mg/kg) ameliorated in vivo bone metastasis of DU145 cells, with improved bone structure and bone mineral density (BMD). Tissue staining indicated a reduction in metastatic DU145 cells and osteoclasts in the bones of ZSTK474-treated mice, compared with the non-treated group.

CONCLUSION

Our result demonstrated the antimetastatic activity of ZSTK474 on prostate cancer DU145 cells, suggesting the potential application in prostate cancer patients.

Design, synthesis and bioevaluation of novel substituted triazines as potential dual PI3K/mTOR inhibitors

A series of novel substituted triazines bearing a benzimidazole scaffold were designed and synthesized based on the structures of known anti-cancer agents, namely gedatolisib and alpelisib. All the target compounds were screened for inhibitory activity against PI3Kα and mTOR kinases. Notably, most analogs exhibited IC₅₀ in the nanomolar range. Investigation of the isozyme selectivity indicated that the compounds exhibited remarkable inhibitory activity against PI3Kδ, especially compound 19f showed an IC₅₀ value of 2.3 nM for PI3Kδ and moderate δ-isozyme selectivity over other class I PI3K isoforms and mTOR (with IC₅₀ values of 14.6, 34.0, 849.0 and 15.4 nM for PI3Kα, β, γ and mTOR, respectively). An in vitro MTT assay was conducted to assess the antiproliferative and cytotoxic effects of the prepared analogs. It was revealed that the compounds displayed significant inhibitory activities against the HCT116 human colon cancer cell line. Compound 19i showed 4.7-fold higher potency than the positive control gedatolisib (0.3 vs. 1.4 μM, IC₅₀ values). Phosphoblot studies demonstrated that 19c and 19i could significantly suppress the PI3K/Akt/mTOR signaling pathway at 10 μM. Moreover, analogs 19b, 19c and 19i displayed better stability in artificial gastric fluids than gedatolisib, while 19i was indicated not very stable in rat liver microsomes, and may occur phase I metabolic transformations.

Identification of Phosphoinositide-3 Kinases Delta and Gamma Dual Inhibitors Based on the p110δ/γ Crystal Structure

Background:

Phosphoinositide-3 kinases (PI3Ks) are key signaling molecules that affect a diverse array of biological processes in cells, including proliferation, differentiation, survival, and metabolism. The abnormal activity of PI3K signals is closely related to the occurrence of many diseases, which has become a very promising drug target, especially for the treatment of cancer. PI3Kδ/γ inhibitors can reduce toxicity concerns for chronic indications such as asthma and rheumatoid arthritis compared with pan PI3Ks inhibitors.

Methods:

With the aim of finding more effective PI3Kδ/γ dual inhibitors, virtual screening, ADMET prediction Molecular Dynamics (MD) simulations and MM-GBSA were executed based on the known p110δ/γ crystal structure. Compound ZINC28564067 with high docking score and low toxicity was obtained.

Results:

By MD simulations and MM-GBSA, we could observe that ZINC28564067 had more favorable conformation binding to the PI3Kδ/γ than the original ligands.

Conclusion:

The results provided a rapid approach for the discovery of novel PI3Kδ/γ dual inhibitors which might be a potential anti-tumor lead compound.

Design, synthesis and antiproliferative activity evaluation of a series of pyrrolo[2,1-f][1,2,4]triazine derivatives

A series of 6-aminocarbonyl pyrrolo[2,1-f][1,2,4]triazine derivatives were designed by scaffold hopping strategy. The IC₅₀ values of compound 14a against PI3Ks were measured, showing selective activity against p110α and p110δ with IC₅₀s of 122 nM and 119 nM respectively. All the synthesized compounds were evaluated for their antiproliferative activity against human cancer cells by SRB assay. Compounds 14a, 14p and 14q exhibited potent antiproliferative activity against five types of human cancer cells and the PK property of 14q was also investigated here.

Design, synthesis and biological evaluation of novel 2,4-bismorpholinothieno[3,2-d]pyrimidine and 2-morpholinothieno[3,2-d]pyrimidinone derivatives as potent antitumor agents

To develop novel therapeutic agents with anticancer activities, two series of novel 2,4-bismorpholinyl-thieno[3,2-d]pyrimidine and 2-morpholinothieno[3,2-d]pyrimidinone derivatives were designed, synthesized and evaluated for their biological activities. Among them, compound A₁₂ showed the most potent antitumor activities against HCT116, PC-3, MCF-7, A549 and MDA-MB-231 cell lines with IC₅₀ values of 3.24 μM, 14.37 μM, 7.39 μM, 7.10 μM, and 16.85 μM, respectively. Further explorations in bioactivity were conducted to clarify the anticancer mechanism of compound A₁₂. The results showed that compound A₁₂ obviously inhibited the proliferation of A549 cell lines and decreased mitochondrial membrane potential, which led to the apoptosis of cancer cells and suppressed the migration of tumor cells.

An update on the implications of cyclin D1 in melanomas

Cyclin D1 is a protein encoded by the CCND1 gene, located on 11q13 chromosome, which is a key component of the physiological regulation of the cell cycle. CCND1/cyclin D1 is upregulated in several types of human tumors including melanoma and is currently classified as an oncogene that promotes uncontrolled cell proliferation. Despite the demonstrated importance of CCND1/cyclin D1 as a central oncogene in several types of human tumors, its knowledge in melanoma is still limited. This review examines data published on upregulation of the CCND1 gene and cyclin D1 protein in the melanoma setting, focusing on the pathways and molecular mechanisms involved in the activation of the gene and on the clinical and therapeutic implications.

Design, synthesis and biological evaluation of substituted 2-(thiophen-2-yl)-1,3,5-triazine derivatives as potential dual PI3Kα/mTOR inhibitors

The phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) have been regarded as promising targets for the treatment of cancer. Herein, we synthesized a new series of substituted 2-(thiophen-2-yl)-1,3,5-triazine derivatives as novel PI3Kα/mTOR dual inhibitors for cancer therapy. All compounds were evaluated for the IC₅₀ values against three cancer cell lines (A549, MCF-7 and Hela). Most of the target compounds exhibited moderate to excellent anti-tumor activities against these three tested cancer cell lines especially against A549 and Hela cancer cell lines. Among them, the most promising compound 13g showed excellent anti-tumor potency for A549, MCF-7 and Hela cell lines with IC₅₀ values of 0.20 ± 0.05 µM, 1.25 ± 0.11 µM and 1.03 ± 0.24 µM, respectively. Notably, according to the result of enzymatic activity assay, compound 13g was identified as a novel PI3Kα/mTOR dual inhibitor, which had an approximately 10-fold improvement in mTOR inhibition, compared to the class I PI3K inhibitor 1 (pictilisib, GDC-0941), with IC₅₀ values of 525 nM to 48 nM. And western blot analysis indicated compound 13g could efficiently suppress the phosphorylation of AKT at the dose of 0.1 µM, which further demonstrated compound 13g had significant inhibitory effect on the PI3K/Akt/mTOR pathway. Furthermore, compound 13g could stimulate A549 cells arrest at G0/G1 phase in a dose-dependent manner, and induced apoptosis at a low concentration.

Structure-activity relationships (SAR) of triazine derivatives: Promising antimicrobial agents

The emergence of drug resistance has created unmet medical need for the development of new classes of antibiotics. Innovation of new antibacterial agents with new mode of action remains a high priority universally. Triazines are six-membered, nitrogen-containing heterocyclic scaffold with a wide range of pharmaceutical properties such as antibacterial, antifungal, anticancer, antioxidants, antitubercular, antimalarial, anti-HIV, anticonvulsant, anti-inflammatory, antiulcer, and analgesic activities. The present review focuses on the recent developments in the area of medicinal chemistry to discover various chemical structures as potential antimicrobial agents and their structure-activity relationships (SAR) studies are also discussed for further rational design of this kind of derivatives.

1,3,5-Triazine Analogs: A Potent Anticancer Scaffold

Background:

This review presents the exhaustive exploration of 1,3,5-triazine scaffold for development of analogs of anticancer drugs, over the last century. In the recent years, striazine moiety has been one of the most studied moiety, showing broad-spectrum pharmacological activities such as antibacterial, antifungal, analgesic, anti-HIV, antileishmanial, antitrypanosomal, antimalarial and antiviral. Nowadays, many boffins are have become interested in novel synthesis of s-triazine derivatives because of low cost and ease of availability.

Methods:

This scaffold has been extensively investigated mainly in the past decade. Many products have been synthesized from different starting materials and these synthetic products possess anticancer potential against various cell lines.

Results:

Many 1,3,5-triazine analogs exhibited significant anticancer activity in various models and cell lines exhibiting different mechanisms. Some analogs have also shown good pharmacokinetic parameters with less IC50 values.

Conclusion:

Various 1,3,5-triazine analogs have shown potent activities and may be regarded as clinical candidates for future anticancer formulations. This review may be helpful to those researchers seeking required information with regard to the drug design and medicinal properties of 1,3,5-triazine derivatives for selected targets. This review may also offer help to find and improve clinically viable anticancer molecules.