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Breast cancer is a heterogeneous disease that represents the most common cancer around the world; it comprises 12% of new cases according to the World Health Organization. Despite new approaches in early diagnosis and current treatment, breast cancer is still the leading cause of death for cancer mortality. New targeted therapies against key signalling transduction molecules are required. Phosphoinositide 3-kinase (PI3K) regulates multiple biological functions such as proliferation, survival, migration, and growth. It is well established that PI3K isoform-selective inhibitors show fewer toxic side effects compared to broad spectrum inhibition of PI3K (pan-PI3K inhibitors). Therefore, we tested the PI3K p110δ-selective inhibitor, IC87114, and Vps34-selective inhibitor, Vps34-IN1, on the breast cancer cell lines MCF-7 and MDA-MB-231, representing hormone-responsive and triple-negative breast cancer cells, respectively. Our data show that both inhibitors decreased migration of MCF-7 and MDA-MB-231 cells, and Vps34 also significantly impacted MCF-7 cell proliferation. Three-dimensional (3D) in vitro culture models show that IC87114 and Vps34-IN1 treatment reduced the growth of MCF-7 and MDA-MB-231 cells in 3D tumour spheroid cultures. This study identifies IC87114 and Vps34-IN1 as potential therapeutic approaches in breast cancer. [ABSTRACT FROM AUTHOR]

Activated phosphoinositide 3‐kinase delta syndrome (APDS) is a recently described form of inborn error of immunity (IEI) caused by heterozygous mutations in PIK3CD or PIK3R1 genes, respectively, encoding leukocyte‐restricted catalytic p110δ subunit and the ubiquitously expressed regulatory p85 α subunit of the phosphoinositide 3‐kinase δ (PI3Kδ). The first described patients with respiratory infections, hypogammaglobulinemia with normal to elevated IgM serum levels, lymphopenia, and lymphoproliferation. Since the original description, it is becoming evident that the onset of disease may be somewhat variable over time, both in terms of age at presentation and in terms of clinical and immunological complications. In many cases, patients are referred to various specialists such as hematologists, rheumatologists, gastroenterologists, and others, before an immunological evaluation is performed, leading to delay in diagnosis, which negatively affects their prognosis. The significant heterogeneity in the clinical and immunological features affecting APDS patients requires awareness among clinicians since good results with p110δ inhibitors have been reported, certainly ameliorating these patients' quality of life and prognosis. [ABSTRACT FROM AUTHOR]

Activated phosphoinositide 3‐kinase delta syndrome (APDS) is a recently described form of inborn error of immunity (IEI) caused by heterozygous mutations in PIK3CD or PIK3R1 genes, respectively, encoding leukocyte‐restricted catalytic p110δ subunit and the ubiquitously expressed regulatory p85 α subunit of the phosphoinositide 3‐kinase δ (PI3Kδ). The first described patients with respiratory infections, hypogammaglobulinemia with normal to elevated IgM serum levels, lymphopenia, and lymphoproliferation. Since the original description, it is becoming evident that the onset of disease may be somewhat variable over time, both in terms of age at presentation and in terms of clinical and immunological complications. In many cases, patients are referred to various specialists such as hematologists, rheumatologists, gastroenterologists, and others, before an immunological evaluation is performed, leading to delay in diagnosis, which negatively affects their prognosis. The significant heterogeneity in the clinical and immunological features affecting APDS patients requires awareness among clinicians since good results with p110δ inhibitors have been reported, certainly ameliorating these patients' quality of life and prognosis. [ABSTRACT FROM AUTHOR]

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

Abstract This study reports on a novel activating p110δ mutation causing adult-onset hypogammaglobulinemia with lymphopenia without the classical presentation of atypical Activated phosphoinositide 3-kinase δ syndrome (ADPS-1), underlining thus the heterogeneous clinical and immunological presentation of p110δ mutated individuals and offers additional data on the role of p110δ in early and late B cell development in humans. Highlights • We report on a novel activating p110δ mutation causing atypical APDS-1. • Activating mutations in p110δ may not be associated with lymphoproliferation and gastrointestinal or lung involvement. • Activating mutations in p110δ influence early and late B cell development. [ABSTRACT FROM AUTHOR]

Multiple myeloma (MM) is a uniformly fatal disorder of B cells characterized by the accumulation of abnormal plasma cells. Phosphoinositide 3-kinase (PI3K) signaling pathways play a critical regulatory role in MM pathology. Copanlisib, also known as BAY80-6946, is a potent PI3Kα and δ inhibitor. In this study, we investigated the efficacy of copanlisib and a proteasome inhibitor using MM cell lines and primary samples. The p110α and δ catalytic subunits of the class PI3K increased, and carfilzomib activity reduced in the presence of a supernatant from the feeder cell line, HS-5. Phosphorylation of Akt and activation of caspase 3 and poly (ADP-ribose) polymerase (PARP) partially reduced upon carfilzomib treatment in the presence of HS-5. Apoptosis also decreased. Copanlisib treatment for 72 h inhibited growth in MM cell lines and induced apoptosis. Combination treatment of MM cells with carfilzomib and copanlisib caused greater cytotoxicity than that caused by either drug alone and increased apoptosis. Caspase 3 activity increased while that of Akt decreased after combination treatment with copanlisib and carfilzomib. Further, copanlisib inhibited vascular endothelial growth factor (VEGF)-mediated angiogenesis in vitro and in vivo. It also inhibited C-X-C motif chemokine 12 (CXCL12)-mediated chemotaxis. The data suggest that administration of the PI3K inhibitor, copanlisib, may be a powerful strategy against stroma-associated drug resistance of MM cells and can enhance the cytotoxic effects of proteasome inhibitors in such residual MM cells. [ABSTRACT FROM AUTHOR]

Background: Dysfunctions in the PI3K/mTOR pathway have gained a lot of attention in autism research. This was initially based on the discovery of several monogenic autism spectrum disorders with mutations or defects in PI3K/ mTOR signaling components. Recent genetic studies corroborate that defective PI3K/mTOR signaling might be a shared pathomechanism in autism disorders of so far unknown etiology, but functional molecular analyses in human cells are rare. The goals of this study were to perform a functional screen of cell lines from patients with idiopathic autism for defects in PI3K/mTOR signaling, to test if further functional analyses are suitable to detect underlying molecular mechanisms, and to evaluate this approach as a biomarker tool to identify therapeutic targets. Methods: We performed phospho-S6- and S6-specific ELISA experiments on 21 lymphoblastoid cell lines from the AGRE collection and on 37 lymphoblastoid cell lines from the Simons Simplex Collection and their healthy siblings. Cell lines from one individual with increased S6 phosphorylation and his multiplex family were analyzed in further detail to identify upstream defects in PI3K signaling associated with autism diagnosis. Results: We detected significantly increased S6 phosphorylation in 3 of the 21 lymphoblastoid cell lines from AGRE compared to a healthy control and in 1 of the 37 lymphoblastoid cell lines from the Simons Simplex Collection compared to the healthy sibling. Further analysis of cells from one individual with elevated S6 phosphorylation showed increased expression of the PI3K catalytic subunit p110δ, which was also observed in lymphoblastoid cells from other autistic siblings but not unaffected members in his multiplex family. The p110δ-selective inhibitor IC87114 reduced elevated S6 phosphorylation and protein synthesis in this cell line. Conclusions: Our results suggest that functional analysis of PI3K/mTOR signaling is a biomarker tool to identify disease-associated molecular defects that could serve as therapeutic targets in autism. Using this approach, we discovered impaired signaling and protein synthesis through the PI3K catalytic subunit p110δ as an underlying molecular defect and potential treatment target in select autism spectrum disorders. Increased p110δ activity was recently associated with schizophrenia, and our results suggest that p110δ may also be implicated in autism. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) is an autoimmune disease accompanying excessive inflammatory responses. Phosphoinositide 3-kinase p110δ (PI3Kδ) is reported to associate with autoimmune conditions. We here aimed to determine whether selective inhibition of PI3Kδ is effective in a lupus model of BXSB mice, using the selective PI3Kδ inhibitor IC87114, which was intraperitoneally administrated to BXSB mice aged from 14 to 22 weeks. We showed that IC87114 improved renal function by decreasing the levels of proteinuria and serum creatinine, ameliorating the pathologic changes of kidneys and IgG and C3 deposition. Serum anti-autoantibody to nuclear antigen, anti-dsDNA, IL-1β, and IL-17 were markedly reduced by IC87114 therapy. Hepatic damage was also inhibited by administration of IC87114. Expression of phosphorylated AKT (p-AKT) and monocyte chemoattractant protein-1 was inhibited and mouse survival improved. In sum, PI3Kδ activation may be a critical factor for escalating autoimmune renal and hepatic damage, and its inhibition may alleviate the autoimmune damage. Our study reveals that the selective blockade of PI3Kδ is effective for mouse SLE. [ABSTRACT FROM AUTHOR]

B-cell receptor (BCR) signaling is essential for normal B-cell development, selection, survival, proliferation, and differentiation into antibody-secreting cells. Similarly, this pathway plays a key role in the pathogenesis of multiple B-cell malignancies. Genetic and pharmacological approaches have established an important role for the Spleen tyrosine kinase (Syk), Bruton's tyrosine kinase (Btk), and phosphatidylinositol 3-kinase isoform p110delta (PI3Kδ) in coupling the BCR and other BCRs to B-cell survival, migration, and activation. In the past few years, several small-molecule inhibitory drugs that target PI3Kδ, Btk, and Syk have been developed and shown to have efficacy in clinical trials for the treatment of several types of B-cell malignancies. Emerging preclinical data have also shown a critical role of BCR signaling in the activation and function of self-reactive B cells that contribute to autoimmune diseases. Because BCR signaling plays a major role in both B-cell-mediated autoimmune inflammation and B-cell malignancies, inhibition of this pathway may represent a promising new strategy for treating these diseases. This review summarizes recent achievements in the mechanism of action, pharmacological properties, and clinical activity and toxicity of these BCR signaling inhibitors, with a focus on their emerging role in treating lymphoid malignancies and autoimmune disorders. [ABSTRACT FROM AUTHOR]

Abstract: Treatment of 32 acute myeloid leukemia (AML) blast samples showing activation of the PI3K and RAS/RAF/MEK/ERK pathways with the PI3K p110δ isoform and MEKinase selective inhibitors, PCN5603 and U0126 produced dose dependent progenitor kill and inhibition of p-Akt Ser473 and p-Erk Tyr204 expression. Normal marrow or blood progenitors were less sensitive to these inhibitors (median PCN5603 IC50s for AML and normal cells 1.5 and 5.8μM and for U0126 9.6 and 25.8μM, respectively). U0126 synergized with PCN5603 for killing of both AML and normal progenitors. However, the synergy was less for normal than for AML cells and the median IC50 of each drug in the combination 7- to 10-fold higher than for AML cells. [Copyright &y& Elsevier]

Colony stimulating factor-1 (CSF-1) and its receptor (CSF-1R) are key regulators of macrophage biology, and their elevated expression in cancer cells has been linked to poor prognosis. CSF-1Rs are thought to function at the plasma membrane. We show here that functional CSF-1Rs are present at the nuclear envelope of various cell types, including primary macrophages, human cancer cell lines, and primary human carcinomas. In response to CSF-1, added to intact cells or isolated nuclei, nucleus-associated CSF-1R became phosphorylated and triggered the phosphorylation of Akt and p27 inside the nucleus. Extracellularly added CSF-1 was also found to colocalize with nucleus-associated CSF-1Rs. All these activities were found to depend selectively on the activity of the p110δ isoform of phosphoinositide 3-kinase (PI3K). This finding was related to the p110δ-dependent translocation of exogenous CSF-1 to the nucleus-associated CSF-1Rs, correlating with a prominent role of p110δ in activation of the Rab5 GTPase, a key regulator of the endocytic trafficking. siRNA-silencing of Rab5a phenocopied p110δ inactivation and nuclear CSF-1 signaling. Our work demonstrates for the first time the presence of functional nucleus-associated CSF-1Rs, which are activated by extracellular CSF-1 by a mechanism that involves p110δ and Rab5 activity. These findings may have important implications in cancer development. [ABSTRACT FROM AUTHOR]

Abstract: Glioblastoma multiforme (GBM) is a highly invasive and aggressive primary brain tumour in which loss of phosphatase and tensin homologue deleted on chromosome 10 (PTEN), a negative regulator of PI3K signalling, is a common feature. PTEN/PI3K/Akt signalling is involved in the regulation of proliferation, apoptosis and cell migration. Deregulation of PI3K signalling is considered an essential driver in gliomagenesis. However, the role of different PI3K isoforms in glioma is still largely unclear. Here we show that the catalytic PI3K isoform p110δ is consistently expressed at a high level in various glioma cell lines. We used small interfering RNA to selectively deplete p110δ and to determine its tumourigenic roles in PTEN-deficient cells. Interestingly, knockdown of p110δ decreased the cell migration and invasion ability of all GBM cell lines tested. Mechanistically, p110δ knockdown reduced the protein levels of focal adhesion kinase and cell division cycle 42, key regulators of cellular migration. In contrast, pharmacologic inhibition of p110δ by IC87114 or CAL-101 also clearly impaired glioma cell migration but had no obvious effect on the invasion capacity thus pinpointing to possible kinase-dependent and -independent roles of p110δ in glioma pathology. In summary, our data provide novel evidence that in glioma cells p110δ is a key regulator of cell movement and thus may contribute to the highly invasive phenotype of GBM. Isoform specific targeting of PI3Kδ may be beneficial in the treatment of glioblastoma multiforme by specifically inhibiting tumour cell migration capacity. [Copyright &y& Elsevier]

We have investigated the function of the p110d catalytic subunit of phosphoinositide 3-kinase (PI 3-kinase) in platelets using p110d knock-out (p110d –/– ) mice and p110d knock-in (p110d D910A/D910A ) mice, which express a catalytically inactive form of the enzyme. Aggregation to threshold concentrations of the GPVI-specific agonist, CRP, was partially reduced in p110d –/– and p110d D910A/D910A platelets. This inhibition was overcome by higher concentrations of CRP. The degree of inhibition was considerably weaker than that induced by LY294002 and wortmannin, which inhibit all isoforms of PI 3-kinase. p110d –/– platelets showed decreased spreading on fibrinogen- or von Willebrand factor (VWF)-coated surfaces under static conditions, whereas they spread normally on collagen. LY294002 had a more pronounced inhibitory effect on spreading on all three surfaces. Adhesion and aggregate formation of p110d –/– platelets to collagen or fibrinogen/VWF at intermediate/high rates of shear were normal. This study demonstrates a minor role for the p110d catalytic subunit in mediating platelet activation by the collagen receptor GPVI and integrin aIIbß3. The more pronounced inhibitory effect of LY294002 and wortmannin indicates that other isoforms of PI 3-kinase play a more significant role in signalling by the two platelet glycoprotein receptors. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study provides evidence for the first time for APDS-1 presenting as MAS/HLH, with evident clinical implications in patient's management and prognosis. • APDS-1 may present with MAS/HLH features. • MAS/HLH of undefined aetiology may benefit from additional immunological and functional evaluation. [ABSTRACT FROM AUTHOR]

PI3Ks display integrant significance in T-cell development and differentiation, which is related to host defense against infections. Here, we investigated the role of p110δ isoform of PI3Ks in host defense against chlamydial lung infection in a mouse model. Our data showed that lung infection with Chlamydia muridarum (Cm) activated PI3K/AKT signaling pathway. Compared to WT mice, p110δD910A mice, mice with an inactivating knockin mutation in the p110δ Isoform of PI3Ks, showed more sever disease phenotype and slower recovery, which was associated with reduced Chlamydia- specific Th1 and Th17 immune responses following infection. Further adoptive transfer experiment showed that mice which received CD4+ T cells from infected p110δD910A mice exhibited greater body weight loss and higher bacterial loads in the lung than those which received CD4+ T cells from WT mice following challenge infection. These results provide in vivo evidence that p110δ isoform of PI3Ks plays an important role in host defense against chlamydial infection by promoting CD4+ T-cell immunity. [ABSTRACT FROM AUTHOR]