Cellular function of phosphoinositide 3-kinases: implications for development, homeostasis, and cancer

Characterization of Cutaneous Adverse Events Associated With PI3K Inhibitors in 11 Patients

Introduction

Phosphoinositide 3-kinase (PI3K) inhibitors are a new class of cancer therapeutics that inhibits one or more enzymes in the PI3K/AKT/mTOR tumor growth pathway. As compared to other tyrosine kinase inhibitors, there is evidence that PI3K inhibitors have a higher incidence of severe cutaneous adverse events (CAEs) ranging from 2-21%. There is a lack of further characterization of clinical trials and management options for these CAEs.

Methods

A retrospective chart review of our institution's records between January 2015 and May 2019 was conducted; electronic medical records were queried by using a pharmacy database and ICD-10 codes for patients receiving PI3K inhibitor who experienced CAEs during therapy. These CAEs were characterized by two board-certified dermatologists at a major cancer center.

Results

Eleven patients were identified as having 12 cumulative CAEs. Average time to rash onset was 4 weeks, and the most common identified rashes were eczematous (25%) and morbilliform (17%). Four patients experienced a dose delay, and one patient immediately discontinued their PI3K inhibitor.

Conclusion

Although most CAEs caused by PI3K inhibitors in this study were limited to grade 1-2 and were controlled with topical corticosteroids and oral antihistamines, a number of patients experienced dose impact. This highlights the dermatologist's role in managing and minimizing interruption of therapy while maintaining quality of life.

IBL-202 is synergistic with venetoclax in CLL under in vitro conditions that mimic the tumor microenvironment

The B-cell receptor signaling pathway and dysregulation of the Bcl-2 family of proteins play crucial roles in the pathogenesis of chronic lymphocytic leukemia (CLL). Despite significant advances in the treatment of the disease, relapse and drug resistance are not uncommon. In the current study, we investigated the dual PI3/PIM kinase inhibitor IBL-202 in combination with venetoclax as a treatment option for CLL using both primary CLL cells and TP53-deficient OSU-CLL cells generated using the CRISPR-Cas9 system. IBL-202 and venetoclax were highly synergistic against primary CLL cells cocultured with CD40L fibroblasts (combination index [CI], 0.4, at a fractional effect of 0.9) and TP53-knockout (KO) OSU-CLL cells (CI, 0.5, at a fractional effect of 0.9). Synergy between the drugs was consistent, with a significant (P < .05) reduction in the 50% inhibitory concentration for both drugs. IBL-202 and venetoclax in combination induced cell-cycle arrest and slowed the proliferation of both wild-type and TP53-KO cell lines. The drug combination inhibited AKT phosphorylation, reduced expression of Bcl-xL and NF-κB, and increased the Noxa/Mcl-1 ratio. Downregulation of CXCR4 was consistent with inhibition of the SDF-1α-induced migratory capacity of CLL cells. Synergy between IBL-202 and venetoclax against primary CLL cells cultured under conditions that mimic the tumor microenvironment suggests this drug combination may be effective against CLL cells within the lymph nodes and bone marrow. Furthermore, the efficacy of the combination against the TP53-KO OSU-CLL cell line suggests the combination may be a highly effective treatment strategy for high-risk CLL.

Activated Phosphoinositide 3-Kinase Delta Syndrome 1: Clinical and Immunological Data from an Italian Cohort of Patients

Activated phosphoinositide 3-kinase delta syndrome 1 (APDS-1) is a recently described inborn error of immunity caused by monoallelic gain-of-function mutations in the PIK3CD gene. We reviewed for the first time medical records and laboratory data of eight Italian APDS-1 patients. Recurrent sinopulmonary infections were the most common clinical feature at onset of disease. Seven patients presented lymphoproliferative disease, at onset or during follow-up, one of which resembled hemophagocytic lymphohistiocytosis (HLH). Genetic analysis of the PIK3CD gene revealed three novel mutations: functional testing confirmed their activating nature. In the remaining patients, the previously reported variants p.E1021K (n = 4) and p.E525A (n = 1) were identified. Six patients were started on immunoglobulin replacement treatment (IgRT). One patient successfully underwent hematopoietic stem cell transplantation (HSCT), with good chimerism and no GVHD at 21 months post-HSCT. APDS-1 is a combined immune deficiency with a wide variety of clinical manifestations and a complex immunological presentation. Besides IgRT, specific therapies targeting the PI3Kδ pathway will most likely become a valid aid for the amelioration of patients’ clinical management and their quality of life.

Identification of Novel Thiazolo[5,4-b]Pyridine Derivatives as Potent Phosphoinositide 3-Kinase Inhibitors

A series of novel 2-pyridyl, 4-morpholinyl substituted thiazolo[5,4-b]pyridine analogues have been designed and synthesized in this paper. These thiazolo[5,4-b]pyridines were efficiently prepared in seven steps from commercially available substances in moderate to good yields. All of these N-heterocyclic compounds were characterized by nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS) analysis and tested for phosphoinositide 3-kinase (PI3K) enzymatic assay. The results indicated that these N-heterocyclic compounds showed potent PI3K inhibitory activity, and the IC₅₀ of a representative compound (19a) could reach to 3.6 nm. The structure−activity relationships (SAR) study showed that sulfonamide functionality was important for PI3Kα inhibitory activity, and 2-chloro-4-florophenyl sulfonamide (19b), or 5-chlorothiophene-2-sulfonamide (19c) showed potent inhibitory activity with a nanomolar IC₅₀ value. The pyridyl attached to thiazolo[5,4-b]pyridine was another key structural unit for PI3Kα inhibitory potency, and replacement by phenyl lead to a significant decrease in activity. Enzymatic Inhibition results showed that compound 19a inhibited PI3Kα, PI3Kγ, or PI3Kδ with a nanomolar IC₅₀ value, but its inhibitory activity on PI3Kβ was approximately 10-fold reduced. Further docking analysis revealed that the N-heterocyclic core of compound 19a was directly involved in the binding to the kinase through the key hydrogen bonds interaction.

Metabolic labeling of glycerophospholipids via clickable analogs derivatized at the lipid headgroup

Metabolic labeling, in which substrate analogs containing diminutive tags can infiltrate biosynthetic pathways and generate labeled products in cells, has led to dramatic advancements in the means by which complex biomolecules can be detected and biological processes can be elucidated. Within this realm, metabolic labeling of lipid products, particularly in a manner that is headgroup-specific, brings about a number of technical challenges including the complexity of lipid metabolic pathways as well as the simplicity of biosynthetic precursors to headgroup functionality. As such, only a handful of strategies for metabolic labeling of lipids have thus far been reported. However, these approaches provide enticing examples of how strategic modifications to substrate structures, particularly by introducing clickable moieties, can enable the hijacking of lipid biosynthesis. Furthermore, early work in this field has led to an explosion in diverse applications by which these techniques have been exploited to answer key biological questions or detect and track various lipid-containing biological entities. In this article, we review these efforts and emphasize recent advancements in the development and application of lipid metabolic labeling strategies.

PTEN in Regulating Hematopoiesis and Leukemogenesis

PTEN is one of the most frequently mutated tumor suppressor genes in human cancers. By counteracting the PI3K/AKT/mTOR pathway, PTEN plays an essential role in regulating hematopoietic stem cells (HSCs) self-renewal, migration, lineage commitment, and differentiation. PTEN also plays important roles in suppressing leukemogenesis, especially T-cell acute lymphoblastic leukemia (T-ALL). Herein, we will review the function of PTEN in regulating hematopoiesis and leukemogenesis and discuss potential therapeutic approaches against leukemia with PTEN mutations.

PI3K/AKT/mTOR signaling in gastric cancer: Epigenetics and beyond

PI3K/AKT/mTOR pathway is one of the most important signaling pathways involved in normal cellular processes. Its aberrant activation modulates autophagy, epithelial-mesenchymal transition, apoptosis, chemoresistance, and metastasis in many human cancers. Emerging evidence demonstrates that some infections as well as epigenetic regulatory mechanisms can control PI3K/AKT/mTOR signaling pathway. In this review, we focused on the role of this pathway in gastric cancer development, prognosis, and metastasis, with an emphasis on epigenetic alterations including DNA methylation, histone modifications, and post-transcriptional modulations through non-coding RNAs fluctuations as well as H. pylori and Epstein-Barr virus infections. Finally, we reviewed different molecular targets and therapeutic agents in clinical trials as a potential strategy for gastric cancer treatment through the PI3K/AKT/mTOR pathway.

Alpelisib: A Novel Therapy for Patients With PIK3CA-Mutated Metastatic Breast Cancer

In the United States, 1 in 8 women will be diagnosed with invasive breast cancer in her lifetime. Breast cancer death rates are higher for women in the United States than any other cancer, followed by lung cancer (National Cancer Institute, 2019). More than 70% of breast cancers are hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative, and of those patients, 40% have driver mutations in the gene phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) resulting in damaged phosphatidylinositol 3-kinase (PI3K) and uncontrolled cell growth (Mollon et al., 2018; Setiawan et al., 2009). These patients are initially treated with endocrine therapy, but resistance remains an issue. Inhibition of PI3K is a promising new approach to overcome resistance to endocrine therapy in breast cancer. Previous trials of PI3K inhibitors (pictilisib [GDC-0941], buparlisib [BMK120], and taselisib [GDC-0032]) in breast cancer have shown little efficacy secondary to toxicities due to their nonselectivity to PI3K subunits. Alpelisib is a selective inhibitor of PI3K for patients with HR-positive, HER2-negative, PIK3CA-mutated breast cancer who have progressed on endocrine therapy. This drug review will discuss the pharmacology of alpelisib, current data supporting its place in therapy, management of adverse events, and the clinical implications for advanced practitioners treating patients with HR-positive, HER2-negative breast cancer.

Prevalence of Phosphatidylinositol-3-Kinase (PI3K) Pathway Alterations and Co-alteration of Other Molecular Markers in Breast Cancer

Background: PI3K/AKT signaling pathway is activated in breast cancer and associated with cell survival. We explored the prevalence of PI3K pathway alterations and co-expression with other markers in breast cancer subtypes. Methods: Samples of non-matched primary and metastatic breast cancer submitted to a CLIA-certified genomics laboratory were molecularly profiled to identify pathogenic or presumed pathogenic mutations in the PIK3CA-AKT1-PTEN pathway using next generation sequencing. Cases with loss of PTEN by IHC were also included. The frequency of co-alterations was examined, including DNA damage response pathways and markers of response to immuno-oncology agents. Results: Of 4,895 tumors profiled, 3,558 (72.7%) had at least one alteration in the PIK3CA-AKT1-PTEN pathway: 1,472 (30.1%) harbored a PIK3CA mutation, 174 (3.6%) an AKT1 mutation, 2,682 (54.8%) had PTEN alterations (PTEN mutation in 7.0% and/or PTEN loss by IHC in 51.4% of cases), 81 (1.7%) harbored a PIK3R1 mutation, and 4 (0.08%) a PIK3R2 mutation. Most of the cohort consisted of metastatic sites (n = 2974, 60.8%), with PIK3CA mutation frequency increased in metastatic (32.1%) compared to primary sites (26.9%), p < 0.001. Other PIK3CA mutations were identified in 388 (7.9%) specimens, classified as "off-label," as they were not included in the FDA-approved companion test for PIK3CA mutations. Notable co-alterations included increased PD-L1 expression and high tumor mutational burden in PIK3CA-AKT1-PTEN mutated cohorts. Novel concurrent mutations were identified including CDH1 mutations. Conclusions: Findings from this cohort support further exploration of the clinical benefit of PI3K inhibitors for "off-label" PIK3CA mutations and combination strategies with potential clinical benefit for patients with breast cancer.

Targeted therapies in gynecological cancers: a comprehensive review of clinical evidence

Advanced and recurrent gynecological cancers are associated with poor prognosis and lack of effective treatment. The developments of the molecular mechanisms on cancer progression provide insight into novel targeted therapies, which are emerging as groundbreaking and promising cancer treatment strategies. In gynecologic malignancies, potential therapeutic targeted agents include antiangiogenic agents, poly (ADP-ribose) polymerase (PARP) inhibitors, tumor-intrinsic signaling pathway inhibitors, selective estrogen receptor downregulators, and immune checkpoint inhibitors. In this article, we provide a comprehensive review of the clinical evidence of targeted agents in gynecological cancers and discuss the future implication.

Targeting the PI3K/Akt/mTOR pathway in estrogen-receptor positive HER2 negative advanced breast cancer

Recently many therapeutic classes have emerged in advanced hormone receptor-positive breast cancer, which is the leading cause of cancer death in women. In absence of visceral crisis, treatment relies on endocrine therapy combined with cyclin dependent kinase 4 and 6 inhibitor. Many mechanisms lead to resistance to endocrine therapy, including the activation of intracellular signaling pathways critical for cell survival. Approximately 70% of breast tumors harbor an alteration in the phosphoinositide 3 kinase (PI3K)/Akt pathway, leading to its hyper activation. This pathway is involved in the regulation of growth, proliferation and cell survival as well as in angiogenesis and is consequently a major target in the oncogenesis. An aberrant PIK3CA mutation is a common phenomenon in breast cancer and found in approximately 40% of patients with advanced hormone receptor-positive breast cancer. For the moment, the only positive trials showing a progression free survival benefit in this population are BOLERO-2 (2012), SOLAR-1 (2019), which tested everolimus, a mammalian target of rapamycin inhibitor, and alpelisib, a PI3K inhibitor, and led to their marketing authorization. However, many other inhibitors of this pathway are promising; nevertheless their development is actually limited by toxicity, mainly cutaneous (rash), digestive (diarrhea) and endocrine (diabetes).

Molecular Targets, Pathways, and Therapeutic Implications for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) represents one of the leading causes of cancer mortality worldwide. While significant advances have been made for the treatment of advanced hepatocellular carcinoma in the past few years, the prognosis remains poor and effective biomarkers to guide selection of therapies remain noticeably absent. However, several targeted therapies have been approved in the past few years that have improved the outlook for this disease. In this review, we will highlight the recent therapies approved for the treatment of advanced HCC and discuss promising therapeutic options, targets, and pathways for drug development and consideration for future clinical trials.

Anticancer fungal natural products: Mechanisms of action and biosynthesis

Many fungal metabolites show promising anticancer properties both in vitro and in animal models, and some synthetic analogs of those metabolites have progressed into clinical trials. However, currently, there are still no fungi-derived agents approved as anticancer drugs. Two potential reasons could be envisioned: 1) lacking a clear understanding of their anticancer mechanism of action, 2) unable to supply enough materials to support the preclinical and clinic developments. In this review, we will summarize recent efforts on elucidating the anticancer mechanisms and biosynthetic pathways of several promising anticancer fungal natural products.

P55PIK Regulates P53-Dependent Apoptosis in Cancer Cells by Interacting with P53 DNA-Specific Domain

Purpose

Phosphatidylinositol 3-kinase (PI3K) plays an important role in tumorigenesis by cross-talking with several signaling pathways. p55PIK is a unique regulatory subunit of PI3K and contains an extra 24-residue N-terminal domain (N24). This study aimed to explore the interaction of p55PIK with p53 and the role of p55PIK in regulating p53-dependent apoptosis in cancer cells.

Materials and Methods

The expression of p55PIK was detected in cancer cells, and the interaction of p55PIK with p53 was examined by immunoprecipitation and pull-down assay. The expression of p53-dependent apoptosis-related genes was detected by PCR.

Results

N24 domain of p55PIK interacted with DNA-specific binding domain (DBD) of p53. The increase or decrease of p55PIK expression led to the change of the expression of p53 and p53-regulated genes in cancer cells. Moreover, N24 peptide led to the change of the expression of p53-regulated genes. Moreover, a membrane-permeable N24 peptide enhanced p53-dependent apoptosis induced by methyl methanesulfonate.

Conclusion

Our results reveal a novel mechanism that regulates p53-dependent apoptosis in cancer cells via p55PIK-p53 interaction.

Demonstration of Binding Induced Structural Plasticity in a SH2 Domain

SH2 domains are common protein interaction domains able to recognize short aminoacidic sequences presenting a phosphorylated tyrosine (pY). In spite of their fundamental importance for cell physiology there is a lack of information about the mechanism by which these domains recognize and bind their natural ligands. The N-terminal SH2 (N-SH2) domain of PI3K mediates the interaction with different scaffolding proteins and is known to recognize a specific pY-X-X-M consensus sequence. These interactions are at the cross roads of different molecular pathways and play a key role for cell development and division. By combining mutagenesis, chemical kinetics and NMR, here we provide a complete characterization of the interaction between N-SH2 and a peptide mimicking the scaffolding protein Gab2. Our results highlight that N-SH2 is characterized by a remarkable structural plasticity, with the binding reaction being mediated by a diffused structural region and not solely by the residues located in the binding pocket. Furthermore, the analysis of kinetic data allow us to pinpoint an allosteric network involving residues far from the binding pocket involved in specificity. Results are discussed on the light of previous works on the binding properties of SH2 domains.

A multiscale biophysical model for the recruitment of actin nucleating proteins at the membrane interface

The dynamics and organization of the actin cytoskeleton are crucial to many cellular events such as motility, polarization, cell shaping, and cell division. The intracellular and extracellular signaling associated with this cytoskeletal network is communicated through cell membranes. Hence the organization of membrane macromolecules and actin filament assembly are highly interdependent. Although the actin-membrane linkage is known to happen through many routes, the major class of interactions is through the direct interaction of actin-binding proteins with the lipid class containing poly-phosphatidylinositols (PPIs). Among the PPIs, phosphatidylinositol bisphosphate (PI(4,5)P₂) acts as a significant factor controlling actin polymerization in the proximity of the membrane by binding to actin-associated proteins. The molecular interactions between these actin-binding proteins and the membrane lipids remain elusive. Here, using molecular modeling, analytical theory, and experimental methods, we investigate the binding of three different actin-binding proteins, mDia2, NWASP, and gelsolin, to membranes containing PI(4,5)P₂ lipids. We perform molecular dynamics simulations on the protein-bilayer system and analyze the membrane binding in the form of hydrogen bonds and salt bridges at various PI(4,5)P₂ and cholesterol concentrations. Our experimental study with PI(4,5)P₂-containing large unilamellar vesicles mimics the computational experiments. Using the multivalencies of the proteins obtained in molecular simulations and the cooperative binding mechanisms of the proteins, we also propose a multivalent binding model that predicts the actin filament distributions at various PI(4,5)P₂ and protein concentrations.

PBT-6, a Novel PI3KC2γ Inhibitor in Rheumatoid Arthritis

Phosphoinositide 3-kinase (PI3K) is considered as a promising therapeutic target for rheumatoid arthritis (RA) because of its involvement in inflammatory processes. However, limited studies have reported the involvement of PI3KC2γ in RA, and the underlying mechanism remains largely unknown. Therefore, we investigated the role of PI3KC2γ as a novel therapeutic target for RA and the effect of its selective inhibitor, PBT-6. In this study, we observed that PI3KC2γ was markedly increased in the synovial fluid and tissue as well as the PBMCs of patients with RA. PBT-6, a novel PI3KC2γ inhibitor, decreased the cell growth of TNF-mediated synovial fibroblasts and LPS-mediated macrophages. Furthermore, PBT-6 inhibited the PI3KC2γ expression and PI3K/ AKT signaling pathway in both synovial fibroblasts and macrophages. In addition, PBT-6 suppressed macrophage migration via CCL2 and osteoclastogenesis. In CIA mice, it significantly inhibited the progression and development of RA by decreasing arthritis scores and paw swelling. Three-dimensional micro-computed tomography confirmed that PBT-6 enhanced the joint structures in CIA mice. Taken together, our findings suggest that PI3KC2γ is a therapeutic target for RA, and PBT-6 could be developed as a novel PI3KC2γ inhibitor to target inflammatory diseases including RA.

Structural and functional characterization of Solanum lycopersicum phosphatidylinositol 3-kinase C2 domain

Phosphatidylinositol 3-kinases (PI3Ks) are characterized by the presence of a C2 domain at the N-terminal end (class I, III); or at both the N-terminal and C-terminal ends (class II), sometimes including a Plextrin homology domain and/or a Ras domain. Plant PI3Ks are analogous to the class III mammalian PI3K. An N-terminal fragment (~170 aa) of the tomato PI3K regulatory domain including the C2 domain, was cloned and expressed in a bacterial system. This protein was purified to homogeneity and its physicochemical properties analyzed. The purified protein showed strong binding with monophosphorylated phosphatidylinositols, and the binding was dependent on calcium ion concentration and pH. In the overall tertiary structure of PI3K, C2 domain showed unique characteristics, having three antiparallel beta-sheets, hydrophobic regions, acidic as well as alkaline motifs, that can enable its membrane binding upon activation. To elucidate the functional significance of C2 domain, transgenic tobacco plants expressing the C2 domain of PI3K were generated. Transgenic plants showed defective pollen development and disrupted seed set. Flowers from the PI3K-C2 transgenic plants showed delayed wilting, and a decrease in ethylene production. It is likely that introduction of the PI3K-C2 segment may have interfered with the normal binding of PI3K to the membrane, delaying the onset of membrane lipid catabolism that lead to senescence.

Response of metastatic mouse invasive lobular carcinoma to mTOR inhibition is partly mediated by the adaptive immune system

Effective treatment of invasive lobular carcinoma (ILC) of the breast is hampered by late detection, invasive growth, distant metastasis, and poor response to chemotherapy. Phosphoinositide 3-kinase (PI3K) signaling, one of the major druggable oncogenic signaling networks, is frequently activated in ILC. We investigated treatment response and resistance to AZD8055, an inhibitor of mammalian target of rapamycin (mTOR), in the K14-cre;Cdh1^Flox/Flox;Trp53^Flox/Flox (KEP) mouse model of metastatic ILC. Inhibition of mTOR signaling blocked the growth of primary KEP tumors as well as the progression of metastatic disease. However, primary tumors and distant metastases eventually acquired resistance after long-term AZD8055 treatment, despite continued effective suppression of mTOR signaling in cancer cells. Interestingly, therapeutic responses were associated with increased expression of genes related to antigen presentation. Consistent with this observation, increased numbers of tumor-infiltrating major histocompatibility complex class II-positive (MHCII+) immune cells were observed in treatment-responsive KEP tumors. Acquisition of treatment resistance was associated with loss of MHCII+ cells and reduced expression of genes related to the adaptive immune system. The therapeutic efficacy of mTOR inhibition was reduced in Rag1^−/- mice lacking mature T and B lymphocytes, compared to immunocompetent mice. Furthermore, therapy responsiveness could be partially rescued by transplanting AZD8055-resistant KEP tumors into treatment-naïve immunocompetent hosts. Collectively, these data indicate that the PI3K signaling pathway is an attractive therapeutic target in invasive lobular carcinoma, and that part of the therapeutic effect of mTOR inhibition is mediated by the adaptive immune system.

Microglia Mediated Neuroinflammation: Focus on PI3K Modulation

Immune activation in the central nervous system involves mostly microglia in response to pathogen invasion or tissue damage, which react, promoting a self-limiting inflammatory response aimed to restore homeostasis. However, prolonged, uncontrolled inflammation may result in the production by microglia of neurotoxic factors that lead to the amplification of the disease state and tissue damage. In particular, specific inducers of inflammation associated with neurodegenerative diseases activate inflammatory processes that result in the production of a number of mediators and cytokines that enhance neurodegenerative processes. Phosphoinositide 3-kinases (PI3Ks) constitute a family of enzymes regulating a wide range of activity, including signal transduction. Recent studies have focused attention on the intracellular role of PI3K and its contribution to neurodegenerative processes. This review illustrates and discusses recent findings about the role of this signaling pathway in the modulation of microglia neuroinflammatory responses linked to neurodegeneration. Finally, we discuss the modulation of PI3K as a potential therapeutic approach helpful for developing innovative therapeutic strategies in neurodegenerative diseases.

Targeting PI3K/AKT/mTOR-mediated autophagy for tumor therapy

Autophagy is a highly conserved catabolic process and participates in a variety of cellular biological activities. The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway, as a critical regulator of autophagy, is involved in the initiation and promotion of a series of pathological disorders including various tumors. Autophagy also participates in regulating the balance between the tumor and the tumor microenvironment. Natural products have been considered a treasure of new drug discoveries and are of great value to medicine. Mounting evidence has suggested that numerous natural products are targeting PI3K/AKT/mTOR-mediated autophagy, thereby suppressing tumor growth. Furthermore, autophagy plays a "double-edged sword" role in different tumors. Targeting PI3K/AKT/mTOR-mediated autophagy is an important therapeutic strategy for a variety of tumors, and plays important roles in enhancing the chemosensitivity of tumor cells and avoiding drug resistance. Therefore, we summarized the roles of PI3K/AKT/mTOR-mediated autophagy in tumorigenesis, progression, and drug resistance of tumors, which may be utilized to design preferably therapeutic strategies for various tumors.

Macelignan inhibits the inflammatory response of microglia and regulates neuronal survival

Neuroinflammation is an important pathological process of neurodegenerative diseases, and microglial contributes to chronic inflammation and neuronal loss in progressive neurodegenerative. Therefore, regulating the inflammatory response of microglia could lead to the discovery of promising treatments for neurodegenerative diseases. In this study, we investigated the effects of the nutmeg plant seed extract, macelignan, on the inflammatory response of microglia and neuronal cell survival. We detected NO and iNOS using the Griess test and Western blotting. We measured phosphoinositide 3 kinase (PI3K)/Akt expression by Western blotting. The release of NO and inflammatory cytokines and the expression of iNOS decreased in a concentration-dependent manner, with an increase in macelignan concentration. PI3K/Akt phosphorylation levels decreased in a dose-dependent manner in lipopolysaccharide (LPS)-activated microglial cells after exposure to macelignan. We also demonstrated that macelignan improved HT22 cell viability, following exposure to a microglial-conditioned medium. Furthermore, macelignan inhibited microglial cell near neurons treated with a hypoxic conditioned medium. Finally, macelignan treatment reduced the expression of p27 and cyclin D1 in neurons cultured in an LPS-activated microglia-conditioned medium. Therefore, these results imply that macelignan can inhibit the inflammatory response of microglia and regulate neuronal survival through the PI3K/Akt pathway.

Influence of follicle size on bovine oocyte lipid composition, follicular metabolic and stress markers, embryo development and blastocyst lipid content

This study assessed the lipid composition of oocytes from different follicle sizes and compared the expression of lipid-related genes and follicular fluid (FF) molecules between groups. We also investigated the functional consequences of differences on embryo development and blastocyst lipid deposits. Oocytes and FF were recovered from different follicle sizes. Oocytes from small (≤5mm) and large (≥6mm) bovine follicles were used to produce Day 7 expanded blastocysts (Day7Ex) and blastocysts that only became expanded at Day 8 (Day8Ex) after insemination. Oocytes from >8mm follicles had the highest lipid content. Few oocyte phospholipid variations were identified between groups. Very long chain fatty acid elongase 6 (ELOVL6) mRNA abundance was reduced in larger follicle-derived oocytes compared with the ≤2mm group. Increased levels of glucose, reactive oxygen species, glutathione and superoxide dismutase activity were also identified in FF from larger follicles. Large follicle-derived embryo development and lipid content of Day7Ex were greater than those derived from small follicles. Day8Ex had greater lipid deposition than Day7Ex. Oocytes and blastocysts exhibited follicle size-specific lipids. Large-follicle oocytes had increased lipid content and became Day7Ex with greater lipid deposition whereas delayed blastocoel expansion associated with a prolonged period of culture determined the lipid accumulation of Day8Ex. The FF microenvironment of large follicles seems to favour embryo development.

PI3Kδ inhibitors for the treatment of cancer: a patent review (2015-present)

Introduction: PI3Kδ is an important subtype of PI3K kinases, which is mainly expressed in leukocytes and plays an important role in the proliferation, differentiation, maturation and self-reaction of B cells. It is an effective target in the treatment of hematological malignancies and autoimmune diseases such as rheumatoid arthritis. Therefore, many pharmaceutical companies and research institutions have focused on the PI3Kδ subtype in an attempt to develop potent and selective PI3Kδ inhibitors.Areas covered: This review aims to provide an overview of the patented selective PI3Kδ inhibitors in treating cancer from 2015 to present.Expert opinion: Due to the importance of PI3Kδ, the development of selective PI3Kδ inhibitors for the treatment of hematoma and autoimmune diseases is expected. On 23 July 2014, the world's first selective PI3Kδ inhibitor, idelalisib, was approved by the FDA for the treatment of CLL, FL and SLL. Moreover, there are still many small molecule selective PI3Kδ inhibitors at different stages of development. The future research effort for development of PI3Kδ inhibitors is to manage the toxicity and lower the side-effects.

Design, Synthesis and Preliminary Biological Evaluation of Benzylsulfone Coumarin Derivatives as Anti-Cancer Agents

In this work, a series of benzylsulfone coumarin derivatives 5a–5o were synthesized and characterized. Kinase inhibitory activity assay indicated that most of the compounds showed considerable activity against PI3K. Anti-tumor activity studies of the active compounds were also carried out in vitro on the Hela, HepG2, H1299, HCT-116, and MCF-7 tumor cell lines by MTS assay. The structure–activity relationships (SARs) of these compounds were analyzed in detail. Compound 5h exhibited the most potent activities against the mentioned cell lines with IC₅₀ values ranging from 18.12 to 32.60 μM, followed by 5m with IC₅₀ values of 29.30–42.14 μM. Furthermore, 5h and 5m clearly retarded the migration of Hela cells in vitro. Next, an in silico molecular docking study was conducted to evaluate the binding models of 5h and 5m towards PI3Kα and PI3Kβ. Collectively, the above findings suggested that compounds 5h and 5m might be promising PI3K inhibitors deserving further investigation for cancer treatment.

Efficacy and safety of buparlisib, a PI3K inhibitor, in patients with malignancies harboring a PI3K pathway activation: a phase 2, open-label, single-arm study

Background: Phosphatidylinositol 3-kinase (PI3K) pathway activation plays a key role in tumorigenesis and has been associated with poor prognosis and resistance to multiple therapies in various cancers. Results: There were 146 patients enrolled; common tumor types were colorectal, sarcoma, and ovarian. Tumors had PI3K pathway alterations and a median of four mutations with tissue-specific patterns of mutation burden (lowest: sarcoma [2.5]; highest: esophagus, germ cell tumor, skin non-melanoma, vaginal [7]). The number of prior therapies did not correlate with the number of genetic alterations (Pearson r = -0.037). The clinical benefit rate was 15.1% (n = 22). An additional patient had an unconfirmed complete response. The most common adverse events were fatigue, nausea, hyperglycemia, decreased appetite, and diarrhea. Patient and Methods: In this phase 2, open-label, single-arm study, patients with solid or hematologic malignancies with PI3K pathway activation and progression on or after standard treatment received buparlisib (100 mg once daily). The primary endpoint was clinical benefit rate per local investigator assessment (response or stable disease at ≥16 weeks). Conclusions: Buparlisib was well tolerated, however efficacy was limited despite selection of PI3K pathway aberrations. Future studies may provide insight into buparlisib efficacy by refining the molecular selection of different tumor types.

Elevated expression of G3BP1 associates with YB1 and p-AKT and predicts poor prognosis in nonsmall cell lung cancer patients after surgical resection

Purpose

G3BP1 is an RNA‐binding protein and plays roles in regulating signaling pathway. YB‐1 is a DNA/RNA binding protein encoded by YBX1 gene. Phosphorylated AKT (p‐AKT) acts as a pivotal molecule in PI3K/AKT pathway. YB‐1 drives stress granules (SGs) formation by activating G3BP1 translation under diverse conditions. SGs are involved in many different metabolic and signaling pathways which may include PI3K/AKT/mTOR. So far, there has been no report on the relationship between expression of G3BP1, p‐AKT, and YB1 and clinicopathological features/prognosis in surgically resected nonsmall cell lung cancer (NSCLC) patients.

Methods

In this study, data from TCGA (The Cancer Genome Atlas) were downloaded to investigate the mRNA expression of G3BP1 and YB1 (YBX1) and their correlation in NSCLC. Also, expression of G3BP1, YB1, and p‐AKT proteins was studied using immunohistochemistry in tissue microarrays of NSCLC and in noncancerous lung tissues.

Results

We found that the mRNA expression of G3BP1 and YB1 was higher in NSCLC tissues (both P < .05), and G3BP1 was positively correlated with YB1 in mRNA level (r = .399, P < .001). Also, expression of G3BP1, YB1, and p‐AKT proteins was higher in NSCLC tissues (all P < .05). And higher expression of G3BP1 and YB1 proteins was seen in patients with clinical stage II and III compared with stage I (both P < .05). Besides, expression of G3BP1 protein had a positive correlation with YB1 and p‐AKT (both P < .05). Moreover, overall survival was shorter in patients with overexpression of G3BP1, YB1, and p‐AKT proteins (all P < .05). Multivariate analysis confirmed that overexpression of G3BP1 protein was an independent poorer prognostic factor for NSCLC patients (P = .039).

Conclusion

G3BP1 may play a crucial role in activating PI3K/AKT/mTOR pathway. G3BP1 might be served as a novel prognostic biomarker for surgically resected NSCLC patients, which afforded new insights into the study on the mechanism and therapy of NSCLC.

Advances in Targeted Therapies for Triple-Negative Breast Cancer

While the outcomes for patients diagnosed with hormone receptor positive (HR+) and/or human epidermal growth factor receptor 2-positive (HER2+) breast cancers have continued to improve with the development of targeted therapies, the same cannot be said yet for those affected with triple-negative breast cancer (TNBC). Currently, the mainstay of treatment for the 10-15% of patients diagnosed with TNBC remains cytotoxic chemotherapy, but it is hoped that through an enhanced characterization of TNBC biology, this disease will be molecularly delineated into subgroups with targetable oncogenic drivers. This review will focus on recent therapeutic innovations for TNBC, including poly-ADP-ribosyl polymerase (PARP) inhibitors, phosphoinositide 3-kinase (PI3K) pathway inhibitors, immune checkpoint inhibitors, and cyclin-dependent kinase (CDK) inhibitors.

For Better or Worse: The Potential for Dose Limiting the On-Target Toxicity of PI 3-Kinase Inhibitors

The hyper-activation of the phosphoinositide (PI) 3-kinase signaling pathway is a hallmark of many cancers and overgrowth syndromes, and as a result, there has been intense interest in the development of drugs that target the various isoforms of PI 3-kinase. Given the key role PI 3-kinases play in many normal cell functions, there is significant potential for the disruption of essential cellular functions by PI 3-kinase inhibitors in normal tissues; so-called on-target drug toxicity. It is, therefore, no surprise that progress within the clinical development of PI 3-kinase inhibitors as single-agent anti-cancer therapies has been slowed by the difficulty of identifying a therapeutic window. The aim of this review is to place the cellular, tissue and whole-body effects of PI 3-kinase inhibition in the context of understanding the potential for dose limiting on-target toxicities and to introduce possible strategies to overcome these.

Sustainability of coral reefs are affected by ecological light pollution in the Gulf of Aqaba/Eilat

As human populations grow and lighting technologies improve, artificial light gradually alters natural cycles of light and dark that have been consistent over long periods of geological and evolutionary time. While considerable ecological implications of artificial light have been identified in both terrestrial and aquatic habitats, knowledge about the physiological and molecular effects of light pollution is vague. To determine if ecological light pollution (ELP) impacts coral biological processes, we characterized the transcriptome of the coral Acropora eurystoma under two different light regimes: control conditions and treatment with light at night. Here we show that corals exposed to ELP have approximately 25 times more differentially expressed genes that regulate cell cycle, cell proliferation, cell growth, protein synthesis and display changes in photo physiology. The finding of this work confirms that ELP acts as a chronic disturbance that may impact the future of coral reefs.

Predictive factors for the development of diabetes in cancer patients treated with phosphatidylinositol 3-kinase inhibitors

PURPOSE

Targeted therapy using phosphatidylinositol 3-kinase (PI3K) inhibitors is used to treat cancer such as lymphoma. In animal studies, its use raised concern about alteration of glucose metabolism. To date, clinical data are inconclusive; therefore, we investigated the incidence and clinical manifestations of diabetes in cancer patients treated with PI3K inhibitors.

METHODS

In a retrospective review of diabetes-free patients with advanced solid tumors treated with PI3K inhibitor, we performed Cox regression to identify independent predictors for the development of diabetes.

RESULTS

Of 38 patients (mean age: 54.5 years, 23.7% female) having a mean duration of follow-up of 238.5 days who initiated PI3K inhibitors, 55.3% developed diabetes during treatment (mean 29.1 days); among these, 28.6% experienced remission of diabetes after discontinuing PI3K inhibitors (mean 72.1 days). Patients with incident diabetes had higher anti-hypertensive medication use, higher HbA1c levels and fasting glucose at baseline, and longer duration of PI3K inhibitor use (P = 0.024, P = 0.005, P = 0.008, and P = 0.023, respectively). Previous steroid use and lower baseline HbA1c level were significantly associated with development of diabetes (HR = 8.41, 95% CI 1.89-37.33; HR = 2.16, 95% CI 1.09-4.25, respectively). Patients whose diabetes remitted after discontinuing PI3K inhibitors were younger (P = 0.035) and had lower fasting glucose levels during PI3K inhibitor treatment (P = 0.001) compared to those non-remitters.

CONCLUSIONS

Previous steroid use and lower baseline HbA1c level may be important predictors for developing diabetes in patients with advanced solid tumors treated with PI3K inhibitors, warranting close observation and careful intervention.

Anticancer compound XL765 as PI3K/mTOR dual inhibitor: A structural insight into the inhibitory mechanism using computational approaches

The PI3K-AKT-mTOR pathway is often a commonly disrupted pathway in human cancer and, therefore, it is widely exploited for cancer therapy. The inhibitors for the important proteins of the pathway including PI3K and mTOR have been increasingly designed. The dual inhibitors targeting PI3K and mTOR both have proven to be more effective than those targeting single protein only. An orally-active compound XL765 is well established as PI3K/mTOR dual inhibitor and have shown in vitro and in vivo anticancer activity against a variety of cancer types and is undergoing clinical trials. The present study explored the exact binding pose and the the interactive forces holding XL765 within the active sites of PI3Kγ and mTOR using molecular docking analyses. The XL765 interacting residues of both the proteins were delineated and the degree of participation in binding was estimated by various methods. In the process, among the interacting residues of PI3Kγ, the Lys-890 and the Met-953 were recognized as the key residues involved in XL765 binding. While, in mTOR case, the Trp-2239 was recognized as the key residue playing role in the XL765 binding. In order to explore the better inhibitors, the study also generated combinatorial chemical library by modifying the scaffold considered from XL765. The virtual screening of the generated compound library led to identification of six novel promising compounds proposed as PI3K/mTOR dual inhibitors. Thus, the present work will through light on the drug inhibitory mechanism of XL765 for PI3K and mTOR, and will also assist in designing novel efficacious drug candidates.

Phase I study of BGT226, a pan-PI3K and mTOR inhibitor, in Japanese patients with advanced solid cancers

The phosphatidylinositol 3-kinase (PI3K) pathway is a promising therapeutic target for various cancers. BGT226 is a pan-PI3K and mammalian target of rapamycin (mTOR) inhibitor. The tolerability and pharmacokinetics/pharmacodynamics of BGT226 were investigated in a phase I study in Japanese patients with advanced solid cancers. BGT226 was orally administered on days 1, 3, and 5 of each week. The initial dose of 10 mg was subsequently escalated to 20, 40, 80, and 100 mg in a cohort of three patients. Pharmacokinetics and pharmacodynamics were investigated using plasma, normal skin, and tumor samples. A total of 18 patients were enrolled and evaluated. The most frequently reported toxicities were diarrhea, nausea, decreased appetite, vomiting, and fatigue. They were all grade 1 or 2, and no dose-limiting toxicity was observed. However, all six patients treated at 100 mg experienced diarrhea and nausea, while two experienced a dose reduction and/or interruptions during the study. Two of five patients who exhibited stable disease continued the study treatment for ≥ 16 weeks. The absorption of BGT226 was rapid, and systemic exposure increased in a dose-dependent manner. Treatment with BGT226 did not change any of the biomarkers in neither normal skin nor tumor tissues. BGT226 was tolerated up to 100 mg three times a week in Japanese patients with solid cancers, without difference in toxicity profiles and pharmacokinetics compared to Western patients.

Potent Antineoplastic Effects of Combined PI3Kα-MNK Inhibition in Medulloblastoma

Medulloblastoma is a highly malignant pediatric brain tumor associated with poor outcome. Developing treatments that target the cancer stem cell (CSC) population in medulloblastoma are important to prevent tumor relapse and induce long-lasting clinical responses. We utilized medulloblastoma neurospheres that display CSC characteristics and found activation of the PI3K/AKT pathway in sphere-forming cells. Of all class IA PI3Ks, only the PI3Kα isoform was required for sphere formation by medulloblastoma cells. Knockdown of p110α, but not p110β or p110δ, significantly disrupted cancer stem cell frequencies as determined by extreme limiting dilution analysis (ELDA), indicating an essential role for the PI3Kα catalytic isoform in medulloblastoma CSCs. Importantly, pharmacologic inhibition of the MAPK-interacting kinase (MNK) enhanced the antineoplastic effects of targeted PI3Kα inhibition in medulloblastoma. This indicates that MNK signaling promotes survival in medulloblastoma, suggesting dual PI3Kα and MNK inhibition may provide a novel approach to target and eliminate medulloblastoma CSCs. We also observed a significant reduction in tumor formation in subcutaneous and intracranial mouse xenograft models, which further suggests that this combinatorial approach may represent an efficient therapeutic strategy for medulloblastoma. IMPLICATIONS: These findings raise the possibility of a unique therapeutic approach for medulloblastoma, involving MNK targeting to sensitize medulloblastoma CSCs to PI3Kα inhibition.

Target identification, screening and in vivo evaluation of pyrrolone-fused benzosuberene compounds against human epilepsy using Zebrafish model of pentylenetetrazol-induced seizures

Pyrrolone-fused benzosuberene (PBS) compounds were semi-synthesized from α,β,γ-Himachalenes extracted from the essential oil of Cedrus deodara following amino-vinyl-bromide substituted benzosuberenes as intermediates. These PBSs compounds classified as an attractive source of therapeutics. The α-isoform of PI3K which is a pivotal modulator of PI3K/AKT/mTOR signaling pathway, responsible for neurological disorders like epilepsy, found as a potential target molecule against these 17 semi-synthesized PBS compounds using in silico ligand-based pharmacophore mapping and target screening. The compounds screened using binding affinities, ADMET properties, and toxicity that were accessed by in silico docking simulations and pharmacokinetics profiling. Ultimately two compounds viz., PBS-8 and PBS-9 were selected for further in vivo evaluation using a zebrafish (Danio rerio) model of pentylenetetrazol (PTZ)-induced clonic convulsions. Additionally, gene expression studies performed for the genes of the PI3K/AKT/mTOR pathway which further validated our results. In conclusion, these findings suggested that PBS-8 is a promising candidate that could bedeveloped as a potential antiepileptic.

Downregulation of GBAS regulates oral squamous cell carcinoma proliferation and apoptosis via the p53 signaling pathway

Purpose: Oral squamous cell carcinoma (OSCC) is the most common and severe type of head and neck malignancy. The mechanisms by which OSCC arises depend on changes in a number of different factors and genes and the clinicopathological stage of the tumors. Better understanding the possible mechanisms of OSCC would help to identify a new target for molecular targeted therapy. The current study was focused on elucidating the significance of the glioblastoma-amplified sequence (GBAS) on malignant behaviors in OSCC, including proliferation and apoptosis.

Patients and methods: In this study, we measured the levels of mRNA in OSCC and normal oral tissue samples using Affymetrix microarrays. We examined GBAS expression in OSCC tissues and the effect of GBAS knockdown on cell proliferation and apoptosis in vitro and in vivo. The mechanisms underlying GBAS were investigated.

Results: In the present study, GBAS expression was substantially elevated in the majority of tested OSCC tissues. Further, knockdown of GBAS using lentiviral-delivered shRNA in cells had significant effects on cell proliferation, apoptosis and the cell cycle. A xenograft model was also used to assess the tumorigenicity of the GBAS knockdown on OSCC cells in vivo. Mechanistically, GBAS activated p53 signaling by regulating the mRNA and protein expression of CHEK1, AKT1, AKT2 and Bax. Finally, we also investigated the expression of GBAS in patients with OSCC, and the data revealed that GBAS expression was correlated with the rates of relapse and tumor grade.

Conclusion: Our studies provide evidence that GBAS regulates OSCC cell proliferation and apoptosis via p53 signaling, which may be a candidate biomarker for the prognosis and treatment of OSCC.

Mechanism of Apoptosis Induced by Curcumin in Colorectal Cancer

Colorectal cancer (CRC) is among the top three cancer with higher incident and mortality rate worldwide. It is estimated that about over than 1.1 million of death and 2.2 million new cases by the year 2030. The current treatment modalities with the usage of chemo drugs such as FOLFOX and FOLFIRI, surgery and radiotherapy, which are usually accompanied with major side effects, are rarely cured along with poor survival rate and at higher recurrence outcome. This trigger the needs of exploring new natural compounds with anti-cancer properties which possess fewer side effects. Curcumin, a common spice used in ancient medicine was found to induce apoptosis by targeting various molecules and signaling pathways involved in CRC. Disruption of the homeostatic balance between cell proliferation and apoptosis could be one of the promoting factors in colorectal cancer progression. In this review, we describe the current knowledge of apoptosis regulation by curcumin in CRC with regard to molecular targets and associated signaling pathways.

Duvelisib: A 2018 Novel FDA-Approved Small Molecule Inhibiting Phosphoinositide 3-Kinases

Duvelisib (Copiktra^®) is a dual inhibitor of phosphoinositide 3-kinases (PI3Kδ and PI3Kγ). In 2018, duvelisib was first approved by the Food and Drug Administration (FDA) for the treatment of adult patients with relapsed or refractory chronic lymphocytic leukaemia (CLL)/ small lymphocytic lymphoma (SLL) after at least two prior therapies. Duvelisib has also been approved under accelerated track for relapsed or refractory follicular lymphoma (FL) after at least two prior systemic therapies. In this review, we provide a series of information about duvelisib, such as the development of clinical trials for LLC/SLL and FL and the steps used for its synthesis.

Parathyroid hormone-related protein induces fibronectin up-regulation in rat mesangial cells through reactive oxygen species/Src/EGFR signaling

Parathyroid hormone-related protein (PTHrP) is known to be up-regulated in both glomeruli and tubules in patients with diabetic kidney disease (DKD), but its role remains unclear. Previous studies show that PTHrP-induced hypertrophic response in mesangial cells (MCs) and epithelial-mesenchymal transition (EMT) in tubuloepithelial cells can be mediated by TGF-β1. In the present study, although long-term PHTrP (1-34) treatment increased the mRNA and protein level of TGF-β1 in primary rat MCs, fibronectin up-regulation occurred earlier, suggesting that fibronectin induction is independent of TGF-β1/Smad signaling. We thus evaluated the involvement of epidermal growth factor receptor (EGFR) signaling and found that nicotinamide adenine dinucleotide phosphate oxidase-derived reactive oxygen species mediates PTHrP (1-34)-induced Src kinase activation. Src phosphorylates EGFR at tyrosine 845 and then transactive EGFR. Subsequent PI3K activation mediates Akt and ERK1/2 activation. Akt and ERK1/2 discretely lead to excessive protein synthesis of fibronectin. Our study thus demonstrates the new role of PTHrP in fibronectin up-regulation for the first time in glomerular MCs. These data also provided new insights to guide development of therapy for glomerular sclerosis.

Design, synthesis and biological evaluation of novel chromeno[4,3-c]pyrazol-4(2H)-one derivates containing sulfonamido as potential PI3Kα inhibitors

A series of novel chromeno[4,3-c]pyrazol-4(2H)-one derivates contained sulfonamido were designed and synthesized, and their anticancer effects in vitro was evaluated to develop some new PI3Kα inhibitors. Most of desired compounds exhibited the better antiproliferative activities against four cancer cell lines than that of LY294002. Out of them, compound 4o displayed the potent antiproliferative activity and high selectivity against the PI3Kα protein and it can induce apoptosis of HCT116 in a dose-dependent manner. Western blot assay indicated that compound 4o obviously down-regulated expression of p-Akt (S473). Molecular docking was performed to clarify the possible binding mode between compound 4o and PI3Kα. All these results indicated that compound 4o could be a potential inhibitor of PI3Kα.

Oral MEK 1/2 Inhibitor Trametinib in Combination With AKT Inhibitor GSK2141795 in Patients With Acute Myeloid Leukemia With RAS Mutations: A Phase II Study

BACKGROUND

With proven single-agent activity and favorable toxicity profile of MEK-1/2 inhibition in advanced leukemia, investigation into combination strategies to overcome proposed resistance pathways is warranted. Resistance to MEK inhibition is secondary to upstream hyperactivation of RAS/RAF or activation of the PI3K/PTEN/AKT/mTOR pathway. This phase II multi-institution Cancer Therapy Evaluation Program-sponsored study was conducted to determine efficacy and safety of the combination of the ATP-competitive pan-AKT inhibitor GSK2141795, targeting the PI3K/AKT pathway, and the MEK inhibitor trametinib in RAS-mutated relapsed/refractory acute myeloid leukemia (AML).

PATIENTS AND METHODS

The primary objective was to determine the proportion of patients achieving a complete remission. Secondary objectives included assessment of toxicity profile and biologic effects of this combination. Twenty-three patients with RAS-mutated AML received the combination. Two dose levels were explored (dose level 1: 2 mg trametinib, 25 mg GSK2141795 and dose level 2: 1.5 mg trametinib, 50 mg GSK2141795).

RESULTS

Dose level 1 was identified as the recommended phase II dose. No complete remissions were identified in either cohort. Minor responses were recognized in 5 (22%) patients. The most common drug-related toxicities included rash and diarrhea, with dose-limiting toxicities of mucositis and colitis. Longitudinal correlative assessment of the modulation of MEK and AKT pathways using reverse phase protein array and phospho-flow analysis revealed significant and near significant down-modulation of pERK and pS6, respectively. Combined MEK and AKT inhibition had no clinical activity in patients with RAS-mutated AML.

CONCLUSION

Further investigation is required to explore the discrepancy between the activity of this combination on leukemia cells and the lack of clinical efficacy.

Phosphoinositide phosphatases in cancer cell dynamics-Beyond PI3K and PTEN

Phosphoinositides are a group of lipids that regulate intracellular signaling and subcellular biological events. The signaling by phosphatidylinositol-3,4,5-trisphosphate and Akt mediates the action of growth factors that are essential for cell proliferation, gene transcription, cell migration, and polarity. The hyperactivation of this signaling has been identified in different cancer cells; and, it has been implicated in oncogenic transformation and cancer cell malignancy. Recent studies have argued the role of phosphoinositides in cancer cell dynamics, including actin cytoskeletal rearrangement at the plasma membrane and the organization of intracellular compartments. The focus of this review is to summarize the impact of the activities of phosphoinositide phosphatases on intracellular signaling related to cancer cell dynamics and to discuss how the abnormalities in the activities of the enzymes alter the levels of phosphoinositides in cancer cells.

Development of Effective Therapeutics Targeting HER3 for Cancer Treatment

HER3 is the third member of the human epidermal growth factor receptor (HER/EGFR) family, and unlike its other family members, is unique due to its minimal intrinsic kinase activity. As a result, HER3 has to interact with another receptor tyrosine kinase (RTK), such as EGFR or HER2, in order to activate the PI-3 K/Akt, MEK/MAPK, Jak/Stat pathways, as well as Src kinase. Over-expression of HER3 in various human cancers promotes tumor progression by increasing metastatic potential and acting as a major cause of treatment failure. Effective inhibition of HER3, and/or the key downstream mediators of HER3 signaling, is thought to be required to overcome resistance and enhance therapeutic efficacy. To date, there is no known HER3-targeted therapy that is approved for breast cancer, with a number of anti-HER3 antibodies current in various stages of development and clinical testing. Recent data suggests that the epigenetic strategy of using a histone deacetylase (HDAC) inhibitor, or functional cooperative miRNAs, may be an effective way to abrogate HER3 signaling. Here, we summarize the latest advances in our understanding of the mechanism of HER3 signaling in tumor progression, with continuing research towards the identification of therapeutic anti-HER3 antibodies. We will also examine the potential to develop novel epigenetic approaches that specifically target the HER3 receptor, along with important key downstream mediators that are involved in cancer treatment.

Individual differences in EPA and DHA content of Atlantic salmon are associated with gene expression of key metabolic processes

The aim of this study was to explore how individual differences in content of the omega-3 fatty acids EPA and DHA in skeletal muscle of slaughter-sized Atlantic salmon, are associated with expression of genes involved in key metabolic processes. All experimental fish were fed the same diet throughout life and fasted for 14 days prior to slaughter. Still, there were relatively large individual variations in EPA and DHA content of skeletal muscle. Higher DHA content was concurrent with increased expression of genes of the glycolytic pathway and the production of pyruvate and lactate, whereas EPA was associated with increased expression of pentose phosphate pathway and glycogen breakdown genes. Furthermore, EPA, but not DHA, was associated with expression of genes involved in insulin signaling. Expression of genes specific for skeletal muscle function were positively associated with both EPA and DHA. EPA and DHA were also associated with expression of genes related to eicosanoid and resolvin production. EPA was negatively associated with expression of genes involved in lipid catabolism. Thus, a possible reason why some individuals have a higher level of EPA in the skeletal muscle is that they deposit - rather than oxidize - EPA for energy.

Targeting PI3K in cancer: mechanisms and advances in clinical trials

Phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling is one of the most important intracellular pathways, which can be considered as a master regulator for cancer. Enormous efforts have been dedicated to the development of drugs targeting PI3K signaling, many of which are currently employed in clinical trials evaluation, and it is becoming increasingly clear that PI3K inhibitors are effective in inhibiting tumor progression. PI3K inhibitors are subdivided into dual PI3K/mTOR inhibitors, pan-PI3K inhibitors and isoform-specific inhibitors. In this review, we performed a critical review to summarize the role of the PI3K pathway in tumor development, recent PI3K inhibitors development based on clinical trials, and the mechanisms of resistance to PI3K inhibition.

Curcumin-induced autophagy and nucleophagy in Spodoptera frugiperda Sf9 insect cells occur via PI3K/AKT/TOR pathways

Compounds from plants or microbes are important resources for new natural pesticides against a wide variety of pests. The growing attention on the role of autophagy (type II cell death) in regulation of insect toxicology has propelled researchers to investigate autophagic cell death pathways. Our previous study proved that the cytotoxic effect of curcumin in Spodoptera frugiperda cells is regulated by autophagy. However, the signaling pathways and molecular mechanisms had not been determined. The current study elucidates curcumin inhibition of survival signaling by blocking the activation of PI3K/AKT/TOR pathways to induce autophagy in S. frugiperda cells. The result demonstrates that nucleophagy associated with cell death following the curcumin treatment. Following the curcumin treatment, Atg8/LC3 immunostaining in both nucleus and cytoplasm was markedly increased. Further, messenger RNA expression level of Atg8 and Atg1 genes regulation by curcumin was examined using quantitative reverse transcription polymerase chain reaction, and the result exhibited increased level of expression after curcumin treatment in a time-dependent manner. Our current study provides new insights to the autophagy occurring via PI3K/AKT/TOR pathways in S. frugiperda Sf9 insect cells induced by curcumin. Taken together, our results show for the first time that curcumin induced nucleophagy in lepidopteron insect cell line.