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

PI3K p85α Subunit-deficient Macrophages Protect Mice from Acute Colitis due to the Enhancement of IL-10 Production

We investigated the role of the PI3K p85α subunit in the development of acute colitis with a focus on intestinal macrophages. Experimental acute colitis was induced using 3% dextran sulfate sodium (DSS) in drinking water for 7 days. The severity of DSS-induced acute colitis was significantly attenuated in p85α hetero-deficient (p85α+/−) mice compared with WT mice. The expression of proinflammatory mediators in intestinal macrophages isolated from the inflamed colonic mucosa was significantly suppressed in p85α+/− colitis mice compared with WT colitis mice. Interestingly, we found that bone marrow-derived macrophages (BMDMs) from p85α+/− mice produced a significantly higher amount of IL-10 than BMDMs from WT mice. The adoptive transfer of p85α+/− BMDMs, but not WT BMDMs, significantly improved the severity in WT colitis mice, and this effect was reversed by anti-IL-10 antibody. Furthermore, the expression of IL-10 in the intestinal macrophages of p85α+/− normal colonic mucosa was significantly higher than that in the intestinal macrophages of WT normal colonic mucosa. The present results demonstrate that p85α+/− mice exhibit a reduced susceptibility to DSS-induced acute colitis. Our study suggests that a deficiency of PI3K p85α enhances the production of IL-10 in intestinal macrophages, thereby suppressing the development of DSS-induced acute colitis.

Clinical use of lenvatinib in combination with everolimus for the treatment of advanced renal cell carcinoma

INTRODUCTION

Renal cell carcinoma (RCC) represents 2%-3% of all cancers in adults, and its pathogenesis is mainly related to altered cellular response to hypoxia. Lenvatinib, a novel multitarget tyrosine kinase inhibitor (TKI), represents a therapeutic option, in combination with mammalian target of rapamycin (mTOR) inhibitor everolimus, for the treatment of metastatic RCC (mRCC).

AIM

The objective of this article is to review the evidence about the treatment of mRCC with combination of lenvatinib plus everolimus.

EVIDENCE REVIEW

Phase I studies supported clinical activity of lenvatinib in mRCC. A randomized, Phase II, open-label, multicenter trial demonstrated the clinical efficacy of combination treatment with lenvatinib plus everolimus in patients with progressive mRCC after prior therapy with TKI. Median progression-free survival was improved by 9 months with the combination therapy compared to the single-agent everolimus, with an overall response rate of 43% for the experimental regimen. Lenvatinib plus everolimus appeared to be slightly less toxic than single-agent lenvatinib and more toxic than single-agent everolimus; grade 3-4 adverse events occurred in 71% of patients. Currently, lenvatinib plus everolimus has US Food and Drug Administration approval for its use in mRCC after failure of previous treatment with TKI.

CONCLUSION

The combination therapy with lenvatinib plus everolimus might be a promising choice for second-line treatment of mRCC patients. Based on the results of the Phase II trial, it is possible to speculate that the combination therapy could be appropriate for patients with high disease burden or strongly symptomatic patients.

Combining properties of different classes of PI3Kα inhibitors to understand the molecular features that confer selectivity

Phosphoinositide 3-kinases (PI3Ks) are major regulators of many cellular functions, and hyperactivation of PI3K cell signalling pathways is a major target for anticancer drug discovery. PI3Kα is the isoform most implicated in cancer, and our aim is to selectively inhibit this isoform, which may be more beneficial than concurrent inhibition of all Class I PI3Ks. We have used structure-guided design to merge high-selectivity and high-affinity characteristics found in existing compounds. Molecular docking, including the prediction of water-mediated interactions, was used to model interactions between the ligands and the PI3Kα affinity pocket. Inhibition was tested using lipid kinase assays, and active compounds were tested for effects on PI3K cell signalling. The first-generation compounds synthesized had IC₅₀ (half maximal inhibitory concentration) values >4 μM for PI3Kα yet were selective for PI3Kα over the other Class I isoforms (β, δ and γ). The second-generation compounds explored were predicted to better engage the affinity pocket through direct and water-mediated interactions with the enzyme, and the IC₅₀ values decreased by ∼30-fold. Cell signalling analysis showed that some of the new PI3Kα inhibitors were more active in the H1047R mutant bearing cell lines SK-OV-3 and T47D, compared with the E545K mutant harbouring MCF-7 cell line. In conclusion, we have used a structure-based design approach to combine features from two different compound classes to create new PI3Kα-selective inhibitors. This provides new insights into the contribution of different chemical units and interactions with different parts of the active site to the selectivity and potency of PI3Kα inhibitors.

Pharmacotherapy of relapsed/refractory chronic lymphocytic leukemia

INTRODUCTION

The treatment of relapsed/refractory (RR) CLL has been revolutionized by the advent of the new oral inhibitors of B-cell receptor (BCR) signaling and the pro-survival protein, B-cell lymphoma 2 (BCL2). Additionally, new and more potent monoclonal antibodies against CD20 have replaced/may replace rituximab in many settings. Areas covered: Herein, we review the entire therapeutic landscape of RR CLL, with particular attention to the new small-molecule kinase inhibitors and BH3-mimetics. We discuss preclinical data with these agents in CLL, cover available efficacy and safety information, and examine potential resistance mechanisms and possible rational combinations to circumvent them. Expert opinion: The availability of potent and selective inhibitors of BCR signaling and of the anti-apoptotic functions of BCL2 has enormously enhanced our therapeutic armamentarium, with unprecedented efficacy now observed in patients who historically had poor outcomes with chemoimmunotherapy (CIT), e.g., those with deletion 17p/11q and/or IGHV-unmutated disease. The next challenge is to optimally sequence these agents and develop rational combinations that will hopefully lead to deeper and more durable remissions than ever seen before. Indeed, long term relapse free survival, already achievable with CIT in patients with genetically favorable-risk disease, now appears to be a realistic possibility for most patients with CLL.

Bmal1 interference impairs hormone synthesis and promotes apoptosis in porcine granulosa cells

In mammals, granulosa cell proliferation, differentiation, luteinization, apoptosis, and hormone synthesis are tightly related to oocyte maturation, follicular development and ovarian function. In current study, we investigated the role of the key circadian clock gene, brain and muscle arnt-like protein-1 (Bmal1), on porcine granulosa cell hormone secretion and apoptosis. The transcription levels of circadian clock genes, including Bmal1 and period circadian clock 2 (Per2), were detected by RT-qPCR. We found that the circadian clock genes exhibited rhythmic change and were further enhanced by dexamethasone synchronization in granulosa cells. Bmal1 knockdown reduced transcriptional levels of hormone receptor genes, including follicle stimulating hormone receptor (Fshr), luteinizing hormone/choriogonadotropin receptor (Lhcgr) and estrogen receptor 2 (Esr2), and decreased the mRNA and protein levels of cytochrome P450 family 11 subfamily A member 1 (Cyp11a1), cytochrome P450 family 19 subfamily A member 1 (Cyp19a1) and steroidogenic acute regulatory protein (Star), which are the key enzymes involved in hormone synthesis. Synthesis of progesterone and estradiol were also inhibited by Bmal1 siRNA treatment in granulosa cells. Moreover, flow cytometry analysis demonstrated suppressing Bmal1 promoted granulosa cells apoptosis. Western blot analysis showed that Bmal1 interference inactivated the PI3K/Akt/mTOR signaling pathway. In conclusion, Bmal1 plays a critical role in secretion of hormone and apoptosis of porcine granulosa cells via the PI3K/Akt/mTOR signaling pathway.

Puquitinib, a novel orally available PI3Kδ inhibitor, exhibits potent antitumor efficacy against acute myeloid leukemia

The PI3Kδ isoform (PIK3CD), also known as P110δ, is predominately expressed in leukocytes and has been implicated as a potential target in the treatment of hematological malignancies. In this report, we detailed the pharmacologic properties of puquitinib, a novel, orally available PI3Kδ inhibitor. Puquitinib, which binds to the ATP‐binding pocket of PI3Kδ, was highly selective and potent for PI3Kδ relative to other PI3K isoforms and a panel of protein kinases, exhibiting low‐nanomolar biochemical and cellular inhibitory potencies. Additional cellular profiling demonstrated that puquitinib inhibited proliferation, induced G₁‐phase cell‐cycle arrest and apoptosis in acute myeloid leukemia (AML) cell lines, through downregulation of PI3K signaling. In in vivo AML xenografts, puquitinib alone showed stronger efficacy than the well‐known p110δ inhibitor, CAL‐101, in association with a reduction in AKT and ERK phosphorylation in tumor tissues, without causing noticeable toxicity. Furthermore, the combination of puquitinib with cytotoxic drugs, especially daunorubicin, yielded significantly stronger antitumor efficacy compared with each agent alone. Thus, puquitinib is a promising agent with pharmacologic properties that are favorable for the treatment of AML.

ΔNp63α is a common inhibitory target in oncogenic PI3K/Ras/Her2-induced cell motility and tumor metastasis

Activation of phosphatidylinositol 3 kinase (PI3K), Ras, and Her2 signaling plays a critical role in cancer development. Hotspot constitutive activating mutations in oncogenes, such as PIK3CA encoding the p110α catalytic subunit or RAS, as well as overexpression of Her2, are frequently found in human tumors and cancers. It has been well established that activation of these oncogenes profoundly promotes tumor metastasis, whereas decreased expression of ΔNp63α, the major protein isoform of the p53-related p63 expressed in epithelial cells, has been associated with cancer metastasis. In this study, we demonstrate that hotspot oncogenic mutations on PIK3CA and RAS, including p110α^H1047R, K-Ras^G12V, and H-Ras^G12V, as well as activation of Her2, all led to suppression of ΔNp63α expression via Akt-fork-head transcription factor 3a (Akt-FOXO3a) signaling, resulting in increased cell motility and tumor metastasis. Expression of ΔNp63α effectively reversed p110α^H1047R-, K-Ras^G12V-, H-Ras^G12V-, or Her2-induced cell motility in vitro and tumor metastasis in mouse models. We show that ΔNp63α was a direct FOXO3a transcriptional target and that expression of FOXO3a and ΔNp63α was correlated in human cancer biopsy samples. Together, these results demonstrate that ΔNp63α is a common inhibitory target of oncogenic PI3K, Ras, and Her2, and that ΔNp63α may function as a critical integrator of oncogenic signaling in cancer metastasis.

Duvelisib: a phosphoinositide-3 kinase δ/γ inhibitor for chronic lymphocytic leukemia

INTRODUCTION

Frontline chemotherapy is successful against chronic lymphocytic leukemia (CLL), but results in untoward toxicity. Further, prognostic factors, cytogenetic anomalies, and compensatory cellular signaling lead to therapy resistance or disease relapse. Therefore, for the past few years, development of targeted therapies is on the rise. PI3K is a major player in the B-cell receptor (BCR) signaling axis, which is critical for the survival and maintenance of B cells. Duvelisib, a PI3K δ/γ dual isoform specific inhibitor that induces apoptosis and reduces cytokine and chemokine levels in vitro, holds promise for CLL. Areas covered: Herein, we review PI3K isoforms and their inhibitors in general, and duvelisib in particular; examine literature on preclinical investigations, pharmacokinetics and clinical studies of duvelisib either as single agent or in combination, for patients with CLL and other lymphoid malignancies. Expert opinion: Duvelisib targets the PI3K δ isoform, which is necessary for cell proliferation and survival, and γ isoform, which is critical for cytokine signaling and pro-inflammatory responses from the microenvironment. In phase I clinical trials, duvelisib as a single agent showed promise for CLL and other lymphoid malignancies. Phase II and III trials of duvelisib alone or in combination with other agents are ongoing.

Aberrant low expression of p85α in stromal fibroblasts promotes breast cancer cell metastasis through exosome-mediated paracrine Wnt10b

P85α, which acts as a tumour suppressor, is frequently found to be downregulated in various human cancers. However, the role of p85α in the tumour microenvironment is unknown. Here, we report that aberrantly low expression of p85α in breast cancer stroma is clinically relevant to breast cancer disease progression. Stromal fibroblasts can acquire the hallmarks of cancer-associated fibroblasts (CAFs) as a result of the loss of p85α expression. Paracrine Wnt10b from p85α-deficient fibroblasts can promote cancer progression via epithelial-to-mesenchymal transition (EMT) induced by the canonical Wnt pathway. Moreover, exosomes have a key role in paracrine Wnt10b transport from fibroblasts to breast cancer epithelial cells. Our results reveal that p85α expression in stromal fibroblasts haves a crucial role in regulating breast cancer tumourigenesis and progression by modifying stromal–epithelial crosstalk and remodelling the tumour microenvironment. Therefore, p85α can function as a tumour suppressor and represent a new candidate for diagnosis, prognosis and targeted therapy.

Progesterone Protects Against Bisphenol A-Induced Arrhythmias in Female Rat Cardiac Myocytes via Rapid Signaling

Bisphenol A (BPA) is an estrogenic endocrine-disrupting chemical (EDC) that has a range of potential adverse health effects. Previously we showed that acute exposure to BPA promoted arrhythmias in female rat hearts through estrogen receptor rapid signaling. Progesterone (P4) and estrogen have antagonistic or complementary actions in a number of tissues and systems. In the current study, we examined the influence and possible protective effect of P4 on the rapid cardiac actions of BPA in female rat cardiac myocytes. Preincubation with physiological concentration (1 nM) of P4 abolished BPA-induced triggered activities in female cardiac myocytes. Further, P4 abrogated BPA-induced alterations in Ca2+ handling, including elevated sarcoplasmic reticulum Ca2+ leak and Ca2+ load. Key to the inhibitory effect of P4 is its blockade of BPA-induced increase in the phosphorylation of phospholamban. At myocyte and protein levels, these inhibitory actions of P4 were blocked by pretreatment with the nuclear P4 receptor (nPR) antagonist RU486. Analysis using membrane-impermeable bovine serum albumin-conjugated P4 suggested that the actions of P4 were mediated by membrane-initiated signaling. Inhibitory G (Gi) protein and phophoinositide-3 kinase (PI3K), but not tyrosine protein kinase activation, were involved in the observed effects of P4. In conclusion, P4 exerts an acute protective effect against BPA-induced arrhythmogenesis in female cardiac myocytes through nPR and the Gi/PI3K signaling pathway. Our findings highlight the importance of considering the impact of EDCs in the context of native hormonals and may provide potential therapeutic strategies for protection against the cardiac toxicities associated with BPA exposure.

Signaling pathways as therapeutic targets in biliary tract cancer

INTRODUCTION

The incidence of biliary tract cancer (BTC) is increasing, and the disease is frequently diagnosed during advanced stages, leading to poor overall survival. Limited treatment options are currently available and novel therapeutic approaches are needed. A number of completed clinical trials have evaluated the role of chemotherapy for BTC, demonstrating a marginal benefit. Thus, there is increased interest in applying targeted therapies for this disease. Areas covered: This review article summarizes the role of chemotherapeutic regimens for the treatment of BTC, and highlights key signal transduction pathways of interest for targeted inhibition. Of particular interest are the MEK or MAP2K (mitogen-activated protein kinase kinase), phosphatidylinositol-3 kinase (PI3K) and signal transducer and activator of transcription-3 (STAT3) pathways. We discuss the available data on several promising inhibitors of these pathways, both in the pre-clinical and clinical settings. Expert opinion: Future treatment strategies should address targeting of MEK, PI3K and STAT3 for BTC, with a focus on combined therapeutic approaches.

AIM2 regulates viability and apoptosis in human colorectal cancer cells via the PI3K/Akt pathway

Absent in melanoma 2 (AIM2) plays an important role in innate immunity as a DNA sensor in the cytoplasm by triggering the assembly of an AIM2 inflammasome that results in caspase-1-mediated inflammatory responses and cell death. In recent years, studies have indicated that AIM2 can suppress cancer cell proliferation, and mutations in the gene encoding AIM2 are frequently identified in patients with colorectal cancer (CRC). However, the mechanism by which AIM2 restricts tumor growth remains unclear. We reconstructed AIM2 expression in HCT116 CRC cells by lentivirus transfection. Using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, we demonstrated that expression of AIM2 inhibited the viability and increased the apoptosis rate of CRC cells, and cell cycle analysis suggested that AIM2 blocked cell cycle transition from G1 to S phase. Western blot analysis showed that AIM2 promoted apoptosis in CRC cells by suppressing the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway. Our data suggest that AIM2 plays a critical role as a tumor suppressor and might serve as a potential therapeutic target in CRC.

Early tyrosine phosphorylation events following adenosine A2A receptor in human neutrophils: identification of regulated pathways

Activation of the adenosine _2A receptor (A_2AR) elevates intracellular levels of cAMP and acts as a physiologic inhibitor of inflammatory neutrophil functions. In this study, we looked into the impact of A_2AR engagement on early phosphorylation events. Neutrophils were stimulated with well-characterized proinflammatory agonists in the absence or presence of an A_2AR agonist {3-[4-[2-[ [6-amino-9-[(2R,3R,4S,5S)-5-(ethylcarbamoyl)-3,4-dihydroxy-oxolan-2-yl]purin-2-yl]amino] ethyl] phenyl] propanoic acid (CGS 21680)}, PGE₂, or a mixture of the compounds RO 20-1724 and forskolin. As assessed by immunoblotting, several proteins were tyrosine phosphorylated; CGS 21680 markedly decreased tyrosine phosphorylation levels of 4 regions (37-45, 50-55, 60, and 70 kDa). Key signaling protein kinases-p38 MAPK, Erk-1/2, PI3K/Akt, Hck, and Syk-showed decreased phosphorylation, whereas Lyn, SHIP-1, or phosphatase and tensin homolog (PTEN) was spared. PGE₂ or the intracellular cAMP-elevating combination of RO 20-1724 and forskolin mostly mimicked the effect of CGS 21680. Together, results unveil intracellular signaling pathways targeted by the A_2AR, some of which might be key in modulating neutrophil functions.

Study of the CD95-Mediated Non-apoptotic Signaling Pathway: PI3K

CD95 is a plasma membrane receptor that belongs to the TNF receptor family (Itoh and Nagata, J Biol Chem 268(15):10932-10937, 1993; Trauth et al., Science 245(4915):301-305, 1989). Accumulating evidence indicate that this so-called death receptor can also trigger non-apoptotic signaling pathways promoting inflammation and oncogenesis (Barnhart et al., Embo J 23(15):3175-3185, 2004; Chen et al., Nature 465(7297):492-496, 2010; Legembre et al., Cell Cycle 3(10):1235-1239, 2004; Legembre et al., EMBO Rep 5(11):1084-1089, 2004; Malleter et al., Cancer Res 73(22):6711-6721, 2013; Tauzin et al., PLoS Biol 9(6):e1001090, 2011). We and others demonstrated that CD95 implements the PI3K signaling pathway through the formation of a molecular complex designated Motility Inducing Signaling Complex (MISC) contributing to cell survival, growth, proliferation, differentiation and motility (Malleter et al., Cancer Res 73(22):6711-6721, 2013; Tauzin et al., PLoS Biol 9(6):e1001090, 2011; Kleber et al., Cancer Cell 13(3):235-248, 2008). This chapter describes how to immunoprecipitate CD95 to characterize MISC involved in PI3K activation.

Aberrant PTEN expression in response to progesterone reduces endometriotic stromal cell apoptosis

In some human cancer cells, PTEN (phosphatase and tensin homolog deleted on chromosome 10) is known to regulate autophagy induction positively through the inhibition of PI3K/AKT pathway, leading to the activation of mTOR, a major negative regulator of autophagy. Recent studies reported that PTEN expression is abnormally decreased in endometriotic lesions. In endometriosis, abnormal PTEN expression may contribute to the alteration of endometrial cell autophagy, which may affect apoptosis because endometrial cell autophagy is directly involved in the regulation of apoptosis. To test this hypothesis, we evaluated the involvement of PTEN in the regulation of autophagy induction in human normal endometrial stromal cells (NESCs). In addition, we sought to determine whether aberrant PTEN expression in endometriotic cyst stromal cells (ECSCs) is associated with autophagy dysregulation, and a subsequent decrease in apoptosis. Our results show that PTEN expression was enhanced by progesterone treatment in NESCs. Subsequently, autophagy and apoptosis induction increased through the inhibition of AKT and mTOR activity. This progesterone-induced increase in apoptosis was reversed by the inhibition of autophagy induction using either mifepristone (progesterone receptor modulator) or PTEN inhibitor. In contrast, progesterone had no significant effects on PTEN expression, AKT, mTOR activity, autophagy or apoptosis in ECSCs. Furthermore, in contrast to normal eutopic endometrium, endometriotic tissues have constant PTEN expression, autophagy and apoptosis throughout the menstrual cycle. In conclusion, our results suggest abnormal PTEN expression in response to progesterone was observed in ECSCs, which led to the dysregulation of autophagy induction via AKT/mTOR signalling and a subsequent decrease in apoptosis.

Buparlisib, a PI3K inhibitor, demonstrates acceptable tolerability and preliminary activity in a phase I trial of patients with advanced leukemias

Phosphatidylinositol-3-kinase (PI3K) signaling plays a crucial role in oncogene-mediated tumor growth and proliferation. Buparlisib (BKM120) is an oral pan-class I PI3K inhibitor. This phase I study was conducted to determine the dose limiting toxicity (DLT) and maximum tolerated dose (MTD) of BKM120 in patients (pts) with relapsed/refractory acute leukemias. Fourteen pts (12 acute myeloid leukemia, 1 acute lymphoblastic leukemia, and 1 mixed phenotype leukemia) were enrolled. Twelve pts received BKM-120 80 mg/day and two 100 mg/day. The MTD was 80 mg/day. Of the 14 patients treated, the best response was stable disease in one patient that lasted 82 days. The median survival for all patients was 75 days (range 10-568). Three patients with a 3q26 chromosome abnormality had a significantly improved median survival of 360 days (range 278-568) as compared to a median survival of 57 days (range, 10-125) among the 11 other patients. The most frequent drug-related toxicities included confusion, mucositis, dysphagia, and fatigue. Western blot profiling revealed a decrease in p-pS6K/total pS6K in 5/7 (71%) available patient samples with a mean quantitative inhibition of 65% (range, 32-100%) and a decrease in p-FOXO3/total FOXO3 in 4/6 (67%) samples with a mean quantitative inhibition of 93% (range, 89-100%). BKM120 administered at 80 mg/day showed modest efficacy and was tolerable in advanced acute leukemias. Am. J. Hematol. 92:7-11, 2017. © 2016 Wiley Periodicals, Inc.

Human β-defensin 3 contains an oncolytic motif that binds PI(4,5)P2 to mediate tumour cell permeabilisation

Cationic antimicrobial peptides (CAPs), including taxonomically diverse defensins, are innate defense molecules that display potent antimicrobial and immunomodulatory activities. Specific CAPs have also been shown to possess anticancer activities; however, their mechanisms of action are not well defined. Recently, the plant defensin NaD1 was shown to induce tumour cell lysis by directly binding to the plasma membrane phosphoinositide, phosphatidylinositol 4,5-bisphosphate (PI(4,5)P₂). The NaD1–lipid interaction was structurally defined by X-ray crystallography, with the defensin forming a dimer that binds PI(4,5)P₂ via its cationic β2-β3 loops in a ‘cationic grip’ conformation. In this study, we show that human β-defensin 3 (HBD-3) contains a homologous β2-β3 loop that binds phosphoinositides. The binding of HBD-3 to PI(4,5)P₂ was shown to be critical for mediating cytolysis of tumour cells, suggesting a conserved mechanism of action for defensins across diverse species. These data not only identify an evolutionary conservation of CAP structure and function for lipid binding, but also suggest that PIP-binding CAPs could be exploited for novel multifunction therapeutics.

ARID1A gene silencing reduces the sensitivity of ovarian clear cell carcinoma to cisplatin

In ovarian clear cell carcinoma (OCCC), the mutation rate of the AT-rich interaction domain 1A (ARID1A) gene is 46-57%. However, the effects of ARID1A gene silencing by small interfering RNA (siRNA) on the sensitivity of OCCC to cisplatin have not been investigated. Thus, this study aimed to elucidate the association between ARID1A gene silencing and drug resistance in OCCC. Three pairs of ARID1A gene siRNA fragments (siRNA-1, siRNA-2 and siRNA-3) were designed and transiently transfected into ES2 OCCC cells using RNAi Max reagent. Western blotting results demonstrated that the transfection reduced ARID1A protein expression levels, with the siRNA-3 group having the lowest levels. The IC₅₀ value, determined using a Cell Counting kit-8 assay, was significantly increased by siRNA-3 transfection compared with that in blank control and negative control groups. The cell survival rate following treatment with 50 µM cisplatin for 48 h was significantly increased in the siRNA-3 group compared with the blank control and negative control groups. Flow cytometric analysis revealed that the apoptosis rate for cisplatin-treated cells was significantly lower in cells with siRNA-3 transfection than in those without, and the apoptosis rate in siRNA-3-transfected cells was lower than that in the negative control group. Western blot analysis showed that the expression level of AKT in cisplatin-treated cells was significantly decreased compared with that in the negative control group, and the AKT expression level in cisplatin-treated cells was significantly higher with siRNA-3 transfection than without. Therefore, the results demonstrated that ARID1A siRNA efficiently decreased ARID1A expression, which reduced cisplatin chemosensitivity and cell apoptosis in ES2 OCCC cells via the regulation of AKT expression.

The Phosphoinositide 3-Kinase Regulates Retrograde Trafficking of the Iron Permease CgFtr1 and Iron Homeostasis in Candida glabrata

The phosphoinositide 3-kinase (PI3K), which phosphorylates phosphatidylinositol and produces PI3P, has been implicated in protein trafficking, intracellular survival, and virulence in the pathogenic yeast Candida glabrata Here, we demonstrate PI3-kinase (CgVps34) to be essential for maintenance of cellular iron homeostasis. We examine how CgVps34 regulates the fundamental process of iron acquisition, and underscore its function in vesicular trafficking as a central determinant. RNA sequencing analysis revealed iron homeostasis genes to be differentially expressed upon CgVps34 disruption. Consistently, the Cgvps34Δ mutant displayed growth attenuation in low- and high-iron media, increased intracellular iron content, elevated mitochondrial aconitase activity, impaired biofilm formation, and extenuated mouse organ colonization potential. Furthermore, we demonstrate for the first time that C. glabrata cells respond to iron limitation by expressing the iron permease CgFtr1 primarily on the cell membrane, and to iron excess via internalization of the plasma membrane-localized CgFtr1 to the vacuole. Our data show that CgVps34 is essential for the latter process. We also report that macrophage-internalized C. glabrata cells express CgFtr1 on the cell membrane indicative of an iron-restricted macrophage internal milieu, and Cgvps34Δ cells display better survival in iron-enriched medium-cultured macrophages. Overall, our data reveal the centrality of PI3K signaling in iron metabolism and host colonization.

Neuroprotective Effects of Salidroside in the MPTP Mouse Model of Parkinson's Disease: Involvement of the PI3K/Akt/GSK3β Pathway

The degenerative loss through apoptosis of dopaminergic neurons in the substantia nigra pars compacta plays a primary role in the progression of Parkinson's disease (PD). Our in vitro experiments suggested that salidroside (Sal) could protect against 1-methyl-4-phenylpyridine-induced cell apoptosis in part by regulating the PI3K/Akt/GSK3β pathway. The current study aims to increase our understanding of the protective mechanisms of Sal in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropypridine- (MPTP-) induced PD mouse model. We found that pretreatment with Sal could protect against MPTP-induced increase of the time of turning downwards and climbing down to the floor. Sal also prevented MPTP-induced decrease of locomotion frequency and the increase of the immobile time. Sal provided a protection of in MPTP-induced loss of tyrosine hydroxylase-positive neurons in SNpc and the level of DA, DOPAC, and HVA in the striatum. Furthermore, Sal could increase the phosphorylation level of Akt and GSK3β, upregulate the ratio of Bcl-2/Bax, and inhibit the activation of caspase-3, caspase-6, and caspase-9. These results show that Sal prevents the loss of dopaminergic neurons and the PI3K/Akt/GSK3β pathway signaling pathway may have mediated the protection of Sal against MPTP, suggesting that Sal may be a potential candidate in neuroprotective treatment for PD.

Role of Class III phosphoinositide 3-kinase in the brain development: possible involvement in specific learning disorders

Class III phosphoinositide 3-kinase (PIK3C3 or mammalian vacuolar protein sorting 34 homolog, Vps34) regulates vesicular trafficking, autophagy, and nutrient sensing. Recently, we reported that PIK3C3 is expressed in mouse cerebral cortex throughout the developmental process, especially at early embryonic stage. We thus examined the role of PIK3C3 in the development of the mouse cerebral cortex. Acute silencing of PIK3C3 with in utero electroporation method caused positional defects of excitatory neurons during corticogenesis. Time-lapse imaging revealed that the abnormal positioning was at least partially because of the reduced migration velocity. When PIK3C3 was silenced in cortical neurons in one hemisphere, axon extension to the contralateral hemisphere was also delayed. These aberrant phenotypes were rescued by RNAi-resistant PIK3C3. Notably, knockdown of PIK3C3 did not affect the cell cycle of neuronal progenitors and stem cells at the ventricular zone. Taken together, PIK3C3 was thought to play a crucial role in corticogenesis through the regulation of excitatory neuron migration and axon extension. Meanwhile, when we performed comparative genomic hybridization on a patient with specific learning disorders, a 107 Kb-deletion was identified on 18q12.3 (nt. 39554147-39661206) that encompasses exons 5-23 of PIK3C3. Notably, the above aberrant migration and axon growth phenotypes were not rescued by the disease-related truncation mutant (172 amino acids) lacking the C-terminal kinase domain. Thus, functional defects of PIK3C3 might impair corticogenesis and relate to the pathophysiology of specific learning disorders and other neurodevelopmental disorders. Acute knockdown of Class III phosphoinositide 3-kinase (PIK3C3) evokes migration defects of excitatory neurons during corticogenesis. PIK3C3-knockdown also disrupts axon outgrowth, but not progenitor proliferation in vivo. Involvement of PIK3C3 in neurodevelopmental disorders might be an interesting future subject since a deletion mutation in PIK3C3 was detected in a patient with specific learning disorders (SLD).

Everolimus in the management of metastatic renal cell carcinoma: an evidence-based review of its place in therapy

Introduction

Renal cell carcinoma (RCC) is the most common type of kidney cancer in adults, and its pathogenesis is strictly related to altered cellular response to hypoxia, in which mTOR signaling pathway is implicated. Everolimus, an mTOR serine/threonine kinase inhibitor, represents a therapeutic option for the treatment of advanced RCC.

Aim

The objective of this article is to review the evidence for the treatment of metastatic RCC with everolimus.

Evidence review

Everolimus was approved for second- and third-line therapy in patients with advanced RCC according to the results of a Phase III pivotal trial that demonstrated a benefit in median progression-free survival of ~2 months compared to placebo after failure of previous lines of therapy, of which at least one was an anti-VEGFR tyrosine kinase inhibitor (TKI). The role of this drug in first-line setting has been investigated in Phase II trials, with no significant clinical benefit, even in combination with bevacizumab. Everolimus activity in non-clear cell RCC is supported by two randomized Phase II trials that confirmed the benefit in second-line setting but not in first line. Recently, two randomized Phase III trials (METEOR and CheckMate 025) demonstrated the inferiority of everolimus in second-line setting compared to the TKI cabozantinib and to the immune checkpoint inhibitor nivolumab, respectively. Moreover, a recent Phase II study demonstrated a significant benefit for the second-line combination treatment with everolimus plus lenvatinib (a novel TKI) in terms of progression-free survival and overall survival compared to the single-agent everolimus. Basing on preclinical data, the main downstream effectors of mTOR cascade, S6RP and its phosphorylated form, could be good predictive biomarkers of response to everolimus. The safety profile of the drug is favorable, with a good cost-effectiveness compared to second-line sorafenib or axitinib, and no significant impact on the quality of life of treated patients has been found.

Conclusion

Everolimus still represents a current standard of treatment for RCC progressive to previous treatment lines with VEGFR-TKI. The evidence about two new molecules, cabozantinib and nivolumab, successfully tested head-to-head with everolimus in recently published Phase III trials, will determine the shift of everolimus to the third-line setting and subsequent lines of treatment.

The impact of heterogeneity in phosphoinositide 3-kinase pathway in human cancer and possible therapeutic treatments

Phosphatidylinositol 3-kinase catalytic subunit alpha (PIK3CA) plays a crucial role in the initiation and progress of cancerous tumors through the overexpression of the PI3K pathway promoting uncontrollable levels of cell proliferation. In addition only Class I PI3K has been discovered to be involved in human cancer due to its unique ability to produce phosphoinositide 3,4,5 trisphosphate (PIP3), which has been discovered to play a crucial role in human oncogenesis. The role of PIK3CA is lucubrated in breast cancer and gastric cancer, but is not well characterized in lung diseases. In this review, we summarized the common biology and mutations in PIK3CA with its related signaling pathways. Furthermore, we elucidated the PIK3CA heterogeneity in different domains, between various cancers and in different lung cancers. We also take a look at current inhibitors such as KP-372-1 (KP-1), KP-372-2 (KP-2), GSK690693, etc. in order to highlight potential treatment of PIK3CA mutations in human cancer and what directions future research should focus on.

The origin and role of innate lymphoid cells in the lung

Innate lymphoid cells (ILCs), a newly identified member of the lymphoid population, play a critical role in the transition from innate to adaptive immunity in host defense. ILCs are important in mucosal barrier immunity, tissue homeostasis, and immune regulation throughout the body. Significant alterations in ILC responses in lung diseases have been observed and reported. Emerging evidence has shown that ILCs are importantly involved in the pathogenesis and development of a variety of lung diseases, i.e., helminth infections, allergic airway inflammation, and airway hyper-responsiveness. However, as a tissue-resident cell population, the role of ILCs in the lung remains poorly characterized. In this review, we discuss the role of ILCs in lung diseases, the mechanisms underlying the ILC-mediated regulation of immunity, and the therapeutic potential of modulating ILC responses.

Experimental verification of a predicted novel microRNA located in human PIK3CA gene with a potential oncogenic function in colorectal cancer

PI3K/AKT signaling is involved in cell survival, proliferation, and migration. In this pathway, PI3Kα enzyme is composed of a regulatory protein encoded by p85 gene and a catalytic protein encoded by PIK3CA gene. Human PIK3CA locus is amplified in several cancers including lung and colorectal cancer (CRC). Therefore, microRNAs (miRNAs) that are encoded within the PIK3CA gene might have a role in cancer development. Here, we report a novel microRNA named PIK3CA-miR1 (EBI accession no. LN626315), which is located within PIK3CA gene. A DNA segment corresponding to PIK3CA-premir1 sequence was transfected in human cell lines that resulted in generation of mature exogenous PIK3CA-miR1. Following the overexpression of PIK3CA-miR1, its predicted target genes (APPL1 and TrkC) were significantly downregulated in the CRC-originated HCT116 and SW480 cell lines, detected by qRT-PCR. Then, dual luciferase assay supported the interaction of PIK3CA-miR1 with APPL1 and TrkC transcripts. Endogenous PIK3CA-miR1 expression was also detected in several cell lines (highly in HCT116 and SW480) and highly in CRC specimens. Consistently, overexpression of PIK3CA-premir1 in HCT116 and SW480 cells resulted in significant reduction of the sub-G1 cell distribution and apoptotic cell rate, as detected by flowcytometry, and resulted in increased cell proliferation, as detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. PIK3CA-miR1 overexpression also resulted in Wnt signaling upregulation detected by Top/Fop assay. Overall, accumulative evidences indicated the presence of a bona fide novel onco-miRNA encoded within the PIK3CA oncogene, which is highly expressed in colorectal cancer and has a survival effect in CRC-originated cells.

Mer receptor tyrosine kinase negatively regulates lipoteichoic acid-induced inflammatory response via PI3K/Akt and SOCS3

Activation of toll-like receptor (TLR) signaling that initiates an innate immune response to pathogens must be strictly regulated to prevent excessive inflammatory damage in the host. Here, we demonstrate that Mer receptor tyrosine kinase (MerTK) is a negative regulatory molecule in the lipoteichoic acid (LTA)-induced inflammatory response. LTA that activated TLR2 signaling concomitantly induced activation of MerTK signaling in RAW264.7 macrophages, including phosphoinositide 3-kinase (PI3K)/Akt and suppressor of cytokine signaling 3 (SOCS3). Moreover, LTA induced MerTK activation in a time-dependent manner, and LTA-induced MerTK activation was dependent on the ligand Gas6. Additionally, pretreatment with a specific Mer-blocking antibody significantly inhibited LTA-induced phosphorylation of MerTK, while further enhancing LTA-induced phosphorylation of IκB-α and NF-κBp65 as well as production of TNF-α and IL-6. Meanwhile, the antibody blockade of MerTK markedly prevented LTA-induced Akt phosphorylation and SOCS3 expression, both of which were crucial for the inhibition of TLR2-mediated immune response. Collectively, these results suggest, for the first time, that MerTK is an intracellular negative feedback regulator that inhibits the inflammatory response of LTA-stimulated macrophages through the PI3K/Akt pathway and SOCS3 protein.

Prognostic and clinical impact of PIK3CA mutation in gastric cancer: pyrosequencing technology and literature review

BACKGROUND

Phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) mutations that activate the PI3K/AKT signaling pathway have been observed in several types of carcinoma and have been associated with patient prognosis. However, the significance of PIK3CA mutations in gastric cancer remains unclear. This retrospective study investigated the relationship between PIK3CA mutations and clinical outcomes in patients with gastric cancer. Additionally, we reviewed the rate of PIK3CA mutations in gastric cancer and the association between PIK3CA mutations and prognosis in human cancers.

METHODS

The study included 208 patients with gastric cancer who underwent surgical resection at Kumamoto University Hospital, Japan, between January 2001 and August 2010. Mutations in PIK3CA exons 9 and 20 were quantified by pyrosequencing assays.

RESULTS

PIK3CA mutations were detected in 25 (12 %) of the 208 patients. Ten patients had c.1634A > G (p.E545G), 10 had c.1624G > A (p.E542K), 13 had c.1633G > A (p.E545K), nine had c.3139C > T (p.H1047R), and 1 had c.3140A > G (p.H1047Y) mutations. PIK3CA mutations were not significantly associated with any clinical, epidemiologic, or pathologic characteristic. Kaplan-Meier analysis showed no significant differences in disease-free survival (log rank P = 0.84) and overall survival (log rank P = 0.74) between patients with and without PIK3CA mutations.

CONCLUSIONS

Mutations in PIK3CA did not correlate with prognosis in patients with gastric cancer, providing additional evidence for the lack of relationship between the two.

A Case of Drug-induced Cutaneous Toxicity Observed in Cynomolgus Monkeys

The purpose of this article is to describe a case of drug-induced cutaneous toxicity observed in cynomolgus monkeys and to introduce approaches attempted in order to elucidate mechanisms. The test article was a small molecule with a ubiquitously distributed target, especially in rapidly dividing cells, and which modulated cell cycle regulation. After 7 consecutive days of oral dosing, animals developed multifocal skin lesions. The lesions were characterized clinically by vesicles and scabs formation and were distributed mainly in thin-skinned areas of the body including the cheek, chest, abdomen, and inner limbs. Microscopically, the lesions were confirmed as epidermal vesicle formation and ulceration. Immunohistochemical staining revealed that the levels within the epidermis where separation (vesicle formation) occurred were not consistent. The differential diagnoses for vesicular skin lesions and our efforts to elucidate the mechanism of toxicity using in-house database searches and immunohistochemistry are discussed. To the best of our knowledge, similar cutaneous toxicity has not been reported previously, although there are reports of other types of cutaneous toxicities. Understanding the mechanisms of the toxicity is very important when assessing human relevancy during drug development. Our investigative approach can be utilized when unusual skin toxicities are observed in the future.

Differential ERK1/2 Signaling and Hypertrophic Response to Endothelin-1 in Cardiomyocytes from SHR and Wistar-Kyoto Rats: A Potential Target for Combination Therapy of Hypertension

Extracellular signal regulated kinase½ (ERK1/2) signaling is critical to endothelin-1 (ET-1)-induced cardiomyocyte hypertrophy. This study was to investigate ERK1/2 signaling and hypertrophic response to ET-1 stimulation in cardiomyocytes (CMs) from spontaneous hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Primary neonatal SHR and WKY CMs were exposed to ET-1 for up to 24 hrs. Minimal basal ERK1/2 phosphorylation was present in WKY CMs, while a significant baseline ERK1/2 phosphorylation was observed in SHR CMs. ET-1 induced a time- and dose-dependent increase in ERK1/2 phosphorylation in both SHR and WKY CMs. However, ET-1-induced ERK1/2 activation occurred much earlier with significantly higher peak phosphorylation level, and stayed elevated for longer duration in SHR CMs than that in WKY CMs. ET-1-induced hypertrophic response was more prominent in SHR CMs than that in WKY CMs as reflected by increased cell surface area, intracellular actin density, and protein synthesis. Pre-treatment with ERK1/2 phosphorylation inhibitor PD98059 completely prevented ET-1-induced ERK1/2 phosphorylation and increases in cell surface area and protein synthesis in SHR and WKY CMs. The specific PI3 kinase inhibitor LY294002 blocked ET-1-induced Akt and ERK1/2 phosphorylation, and protein synthesis in CMs. These data indicated that ERK1/2 signaling was differentially enhanced in CMs, and was associated with increased cardiac hypertrophic response to ET-1 in SHR. ET-1-induced ERK1/2 activation and cardiac hypertrophy appeared to be mediated via PI3 kinase/Akt signaling in SHR and WKY. The differential ERK1/2 activation in SHR CMs by ET-1 might represent a potential target for combination therapy of hypertension.

The Inositide Signaling Pathway As a Target for Treating Gastric Cancer and Colorectal Cancer

Gastric cancer and colorectal cancer are the leading cause of cancer mortality and have a dismal prognosis. The introduction of biological agents to treat these cancers has resulted in improved outcomes, and combination chemotherapy with targeted agents and conventional chemotherapeutic agents is regarded as standard therapy. Additional newly clarified mechanisms of oncogenesis and resistance to targeted agents require the development of new biologic agents. Aberrant activation of the inositide signaling pathway by a loss of function PTEN mutation or gain of function mutation/amplification of PIK3CA is an oncogenic mechanism in gastric cancer and colorectal cancer. Clinical trials with biologic agents that target the inositide signaling pathway are being performed to further improve treatment outcomes of patients with advanced gastric cancer and metastatic colorectal cancer (CRC). In this review we summarize the inositide signaling pathway, the targeted agents that inhibit abnormal activation of this signaling pathway and the clinical trials currently being performed in patients with advanced or metastatic gastric cancer and metastatic CRC using these targeted agents.

Induction of Central Host Signaling Kinases during Pneumococcal Infection of Human THP-1 Cells

Streptococcus pneumoniae is a widespread colonizer of the mucosal epithelia of the upper respiratory tract of human. However, pneumococci are also responsible for numerous local as well as severe systemic infections, especially in children under the age of five and the elderly. Under certain conditions, pneumococci are able to conquer the epithelial barrier, which can lead to a dissemination of the bacteria into underlying tissues and the bloodstream. Here, specialized macrophages represent an essential part of the innate immune system against bacterial intruders. Recognition of the bacteria through different receptors on the surface of macrophages leads thereby to an uptake and elimination of bacteria. Accompanied cytokine release triggers the migration of leukocytes from peripheral blood to the site of infection, where monocytes differentiate into mature macrophages. The rearrangement of the actin cytoskeleton during phagocytosis, resulting in the engulfment of bacteria, is thereby tightly regulated by receptor-mediated phosphorylation cascades of different protein kinases. The molecular cellular processes including the modulation of central protein kinases are only partially solved. In this study, the human monocytic THP-1 cell line was used as a model system to examine the activation of Fcγ and complement receptor-independent signal cascades during infection with S. pneumoniae. Pneumococci cultured either in chemically defined or complex medium showed no significant differences in pneumococcal phagocytosis by phorbol 12-myristate 13-acetate (PMA) differentiated THP-1 cells. Double immuno-fluorescence microscopy and antibiotic protection assays demonstrated a time-dependent uptake and killing of S. pneumoniae 35A inside of macrophages. Infections of THP-1 cells in the presence of specific pharmacological inhibitors revealed a crucial role of actin polymerization and importance of the phosphoinositide 3-kinase (PI3K) and Protein kinase B (Akt) as well during bacterial uptake. The participation of essential host cell signaling kinases in pneumococcal phagocytosis was deciphered for the kinase Akt, ERK1/2, and p38 and phosphoimmunoblots showed an increased phosphorylation and thus activation upon infection with pneumococci. Taken together, this study deciphers host cell kinases in innate immune cells that are induced upon infection with pneumococci and interfere with bacterial clearance after phagocytosis.

EPHA3 regulates the multidrug resistance of small cell lung cancer via the PI3K/BMX/STAT3 signaling pathway

Multidrug resistance (MDR) is a major obstacle to the treatment of small cell lung cancer (SCLC). EPHA3 has been revealed to be the most frequently mutated Eph receptor gene in lung cancer with abnormal expression. Growing evidence indicates that the signaling proteins of EPHA3 downstream, including PI3K, BMX and STAT3, play crucial roles in tumorigenesis and cancer progression. To explore the possible role of EPHA3 in MDR, we assessed the influence of EPHA3 on chemoresistance, cell cycle, apoptosis, and tumor growth, as well as the relationship between EPHA3 and the expression of PI3K, BMX, and STAT3 in SCLC. We observed that overexpression of EPHA3 in SCLC cells decreased chemoresistance by increasing apoptosis and inducing G0/G1 arrest, accompanied by reduced phosphorylation of PI3K/BMX/STAT3 signaling pathway. Knockdown of EPHA3 expression generated a resistant phenotype of SCLC, as a result of decreased apoptosis and induced G2/M phase arrest. And re-expression of EPHA3 in these cells reversed the resistant phenotype. Meanwhile, increased phosphorylation of PI3K/BMX/STAT3 signaling pathway was observed in these cells with EPHA3 deficiency. Notably, both PI3K inhibitor (LY294002) and BMX inhibitor (LFM-A13) impaired the chemoresistance enhanced by EPHA3 deficiency in SCLC cell lines. Furthermore, EPHA3 inhibited growth of SCLC cells in vivo and was correlated with longer overall survival of SCLC patients. Thus, we first provide the evidences that EPHA3 is involved in regulating the MDR of SCLC via PI3K/BMX/STAT3 signaling and may be a new therapeutic target in SCLC.

Analysis of PI3K/mTOR Pathway Biomarkers and Their Prognostic Value in Women with Hormone Receptor-Positive, HER2-Negative Early Breast Cancer

BACKGROUND: The PI3K/AKT/mTOR pathway alterations have been shown to play significant roles in the development, progression, and metastatic spread of breast cancer. Furthermore, they have been implicated in the process of drug resistance, especially endocrinal therapies. In this study, we aimed to define the correlation between the PI3K mutations and the expression of the phosphorylated forms of different downstream molecules in women with estrogen receptor (ER)–positive, human epidermal growth factor receptor 2–negative (luminal) early breast cancer treated at Cairo university hospitals. METHODS: Next-generation sequencing was used to detect mutations in the PIK3CA hotspots (in exons 9 and 20). Immunohistochemistry was performed on tissue microarray blocks prepared from samples of 35 Egyptian luminal breast cancer patients in the pathology department of Centre Léon Bérard (CLB). The intensity and the percentage of stained tumor cells were integrated to define high versus low biomarker expression. The cytoplasmic and nuclear stainings were graded separately. Patients were followed for a median of 4.7 years (2.1 to 6.9 years). Correlation was done between PI3K mutations and the immunohistochemistry expression of pAKT, LKB1, p4EBP1, and pS6 ribosomal protein (pS6RP) with the clinicopathologic features and disease free survival (DFS) of the patients. RESULTS: Median age at diagnosis was 51.3 years (range, 25 to 82 years). Tumors were larger than 20 mm in 79.2% of the cases, whereas 57.9% had axillary lymph node deposits. Only 12.3% of the patients had SBR grade I tumors, 50.8% had grade II, and 36.8% had grade III. ERs were negative in 6 patients (17%) after pathology review. Thirty-two cases were assessable for LKB1 and pAKT, 33 for p4EBP1 and pS6RP, and 24 for PI3K mutations. Nuclear LKB1, cytoplasmic LKB1, nuclear pAKT, cytoplasmic pAKT, nuclear p4EBP1, and cytoplasmic pS6RP expression was high in 65.6%, 62.5%, 62.5%, 68.8%, 42.4%, and 57.6%, respectively. PIK3CA mutations were found in 7 patients (29.2%). PI3K mutations were correlated with nuclear localization of pAKT (i.e., decreased cytoplasmic pAKT, P = .04; and increased nuclear pAKT, P = .10). There was a tendency toward an inverse correlation between PI3K mutations and the expression of pS6RP (P = .10) and p4EBP1 (P = .19). Nuclear LKB1 expression was a marker of good prognosis. It was associated with smaller tumors (P = .05), more ER (P = .08) and progesteron receptor (PgR) positivity (P = .002). In the Kaplan Meier (KM) model, patients with high nuclear LKB1 had longer DFS (hazard ratio = 0.36; 95% confidence interval, 0.15-1.10; P = .08). Nuclear pAKT high expression also carried a tendency toward longer DFS (hazard ratio = 0.51; 95% confidence interval, 0.11-1.16; P = .13). The expression of p4EBP1, pS6RP, and the PI3K mutational status did not show any prognostic significance in our cohort. CONCLUSION: Among the studied biomarkers, only nuclear expression of LKB1 and pAKT tended to predict better survival in breast cancer patients. PI3K mutation was correlated with the expression of nuclear pAKT but not pS6RP or p4EBP1.

Enhanced protection against renal ischemia-reperfusion injury with combined melatonin and exendin-4 in a rodent model

We tested the hypothesis that combined treatment with melatonin, an anti-oxidant, and exendin-4, an anti-inflammatory agent, was superior to either alone for protecting the kidney from ischemia-reperfusion (IR) injury. Male adult Sprague-Dawley rats (n=40) were equally divided into group 1 (sham-operated control), group 2 (IR only, IR=1h/72h), group 3 (IR-exendin-4, 10 µg/kg at 30 min, 24 h, 48 h after IR procedure), group 4 (IR-melatonin, i.p. 50 mg at 30 min, then 20 mg at 6 and 18 h after IR procedure), and group 5 (combined IR-exendin-4-melatonin). All animals were sacrificed by 72 h after IR/sham procedure. The results showed that the kidney injury score, plasma creatinine, and blood urea nitrogen (BUN) levels were highest in group 2 and lowest in group 1, significantly higher in groups 3 and 4 than those in group 5 and significantly higher in group 3 than those in group 4 (all p < 0.001). The protein expressions of inflammatory (toll-like receptor 4, inducible nitric oxide synthase, interleukin-1β), apoptotic (mitochondrial Bax, cleaved caspase-3 and poly(ADP-ribose) polymerase, p53), podocyte integrity (E-cadherin, P-cadherin), and cell survival (phosphatidylinositol-3-kinase/AKT/mammalian target of rapamycin) biomarkers, as well the podocyte dysfunction biomarkers (Wnt1/Wnt4/β-catenin) displayed a pattern identical to that of creatinine level among the five groups (all p < 0.001). Microscopic findings demonstrated that podocyte dysfunction (Wnt1/Wnt4/β-catenin expression) and inflammatory (CD14 and F4/80-positively stained cells) biomarkers exhibited an identical pattern, whereas that of antioxidant (HO-1(+), NQO-1(+) cells) biomarkers showed an opposite pattern compared to that of creatinine level among the five groups (all p < 0.001). Combined melatonin-exendin-4 therapy offered an additional benefit in protecting the kidney from acute IR injury.

Advances in targeted and immunobased therapies for colorectal cancer in the genomic era

Targeted therapies require information on specific defective signaling pathways or mutations. Advances in genomic technologies and cell biology have led to identification of new therapeutic targets associated with signal-transduction pathways. Survival times of patients with colorectal cancer (CRC) can be extended with combinations of conventional cytotoxic agents and targeted therapies. Targeting EGFR- and VEGFR-signaling systems has been the major focus for treatment of metastatic CRC. However, there are still limitations in their clinical application, and new and better drug combinations are needed. This review provides information on EGFR and VEGF inhibitors, new therapeutic agents in the pipeline targeting EGFR and VEGFR pathways, and those targeting other signal-transduction pathways, such as MET, IGF1R, MEK, PI3K, Wnt, Notch, Hedgehog, and death-receptor signaling pathways for treatment of metastatic CRC. Additionally, multitargeted approaches in combination therapies targeting negative-feedback loops, compensatory networks, and cross talk between pathways are highlighted. Then, immunobased strategies to enhance antitumor immunity using specific monoclonal antibodies, such as the immune-checkpoint inhibitors anti-CTLA4 and anti-PD1, as well as the challenges that need to be overcome for increased efficacy of targeted therapies, including drug resistance, predictive markers of response, tumor subtypes, and cancer stem cells, are covered. The review concludes with a brief insight into the applications of next-generation sequencing, expression profiling for tumor subtyping, and the exciting progress made in in silico predictive analysis in the development of a prescription strategy for cancer therapy.

Suppressive effect of exogenous carbon monoxide on endotoxin-stimulated platelet over-activation via the glycoprotein-mediated PI3K-Akt-GSK3β pathway

Platelet activation is an important event involved in the pathophysiological processes of the coagulation system. Clinical evidence has shown that platelets undergo distinctive pathological processes during sepsis. Unfortunately, how platelets physiologically respond to inflammation or sepsis is not well understood. In this study, we used a lipopolysaccharide (LPS)-stimulated platelet model to systemically investigate alterations in membrane glycoprotein expression, molecular signaling, morphology and critical functions of platelets. We found that platelet adhesion, aggregation, secretion, and spreading on immobilized fibrinogen and the expression of platelet membrane glycoproteins were significantly increased by LPS stimulation, and these changes were accompanied by a significant decrease in cGMP levels and an abnormal distribution of platelet α-granules. Exogenous CO reversed these alterations. Profound morphological changes in LPS-stimulated platelets were observed using atomic force microscopy and phase microscopy. Furthermore, the elevated activities of PI3Ks, AKt and GSK-3β were effectively suppressed by exogenous CO, leading to the improvement of platelet function. Together, these results provide evidence that platelet over-activation persists under LPS-stimulation and that exogenous CO plays an important role in suppressing platelet activation via the glycoprotein-mediated PI3K-Akt-GSK3β pathway.

Arginine Relieves the Inflammatory Response and Enhances the Casein Expression in Bovine Mammary Epithelial Cells Induced by Lipopolysaccharide

As one of functional active amino acids, L-arginine holds a key position in immunity. However, the mechanism that arginine modulates cow mammary inflammatory response in ruminant is unclear. Therefore, this study was conducted to investigate the effects of L-arginine on inflammatory response and casein expression after challenging the bovine mammary epithelial cells (BMECs) with lipopolysaccharide (LPS). The cells were divided into four groups, stimulated with or without LPS (10 μg/mL) and treated with or without arginine (100 μg/mL) for 12 h. The concentration of proinflammatory cytokines, inducible nitric oxide synthase (iNOS), mammalian target of rapamycin (mTOR), and Toll-like receptor 4 (TLR4) signaling pathways as well as the casein was determined. The results showed that arginine reduced the LPS-induced production like IL-1β, IL-6, TNF-α, and iNOS. Though the expression of NF-κB was attenuated and the mTOR signaling pathway was upregulated, arginine had no effect on TLR4 expression. In addition, our results show that the content of β-casein and the total casein were enhanced after arginine was supplemented in LPS-induced BMECs. In conclusion, arginine could relieve the inflammatory reaction induced by LPS and enhance the concentration of β-casein and the total casein in bovine mammary epithelial cells.

Lipidome signatures in early bovine embryo development

Mammalian preimplantation embryonic development is a complex, conserved, and well-orchestrated process involving dynamic molecular and structural changes. Understanding membrane lipid profile fluctuation during this crucial period is fundamental to address mechanisms governing embryogenesis. Therefore, the aim of the present work was to perform a comprehensive assessment of stage-specific lipid profiles during early bovine embryonic development and associate with the mRNA abundance of lipid metabolism-related genes (ACSL3, ELOVL5, and ELOVL6) and with the amount of cytoplasmic lipid droplets. Immature oocytes were recovered from slaughterhouse-derived ovaries, two-cell embryos, and eight- to 16-cell embryos, morula, and blastocysts that were in vitro produced under different environmental conditions. Lipid droplets content and mRNA transcript levels for ACSL3, ELOVL5, and ELOVL6, monitored by lipid staining and quantitative polymerase chain reaction, respectively, increased at morula followed by a decrease at blastocyst stage. Relative mRNA abundance changes of ACSL3 were closely related to cytoplasmic lipid droplet accumulation. Characteristic dynamic changes of phospholipid profiles were observed during early embryo development and related to unsaturation level, acyl chain length, and class composition. ELOVL5 and ELOVL6 mRNA levels were suggestive of overexpression of membrane phospholipids containing elongated fatty acids with 16, 18, and 20 carbons. In addition, putative biomarkers of key events of embryogenesis, embryo lipid accumulation, and elongation were identified. This study provides a comprehensive description of stage-specific lipidome signatures and proposes a mechanism to explain its potential relationship with the fluctuation of both cytoplasmic lipid droplets content and mRNA levels of lipid metabolism-related genes during early bovine embryo development.