Phosphatidylinositol 3-kinase Inhibitor Research Articles

FRI610 Phosphatidylinositol 3-kinase Inhibition With Alpelisib Is Safe And Effective In Treating Refractory Hypoglycemia Associated With Malignant Insulinoma

Abstract Disclosure: Y. Kang: None. D.A. Rubinson: None. I. Odintsov: None. A. Vaidya: None. J.S. Williams: None. G.K. Adler: None. M.E. McDonnell: None. M. Patti: Advisory Board Member; Self; Fractyl Laboratories. Consulting Fee; Self; AstraZeneca, Hanmi Pharmaceuticals, MBX. Grant Recipient; Self; Dexcom. N.E. Palermo: None. Background: Nonfunctioning malignant pancreatic neuroendocrine tumors (PNETs) can transform to functional PNETs. Transformation into insulin-secreting PNET (ISPNET) is associated with poor overall survival and refractory hypoglycemia, often requiring ICU care. We present a case of refractory hypoglycemia due to ISPNET, which was successfully treated with alpelisib, an inhibitor of phosphatidylinositol 3-kinase (PI3K) currently approved for breast cancer. Clinical Case: A 79-year-old man with a 5-year history of type 2 diabetes and 10-year history of grade II, well-differentiated, non-functioning PNET (Ki67 15%) with hepatic metastasis presented with worsening symptomatic hypoglycemia. He discontinued his antidiabetic agent 3 months ago due to hypoglycemia and was on lanreotide and everolimus as PNET treatment. Evaluation revealed plasma glucose 29 mg/dL, proinsulin >700 pmol/L (reference: 3.6-22), insulin 116 uIU/mL (2.6-24.9), C-peptide 12.0 ng/mL (1.1-4.4), beta-hydroxybutyrate 0.1 mmol/L (<0.3), and negative sulfonylurea panel. Imaging showed extensive progression of hepatic metastases, and debulking hepatectomy was performed. Pathology showed grade III PNET with positive insulin staining and mib-1 index of 22%. After 2 months of euglycemia post-surgery, he was readmitted to the ICU with refractory hypoglycemia. Evaluation showed plasma glucose 91 mg/dL, proinsulin, and insulin levels above-assay (>700 pmol/L and >930.0 uIU/mL, respectively) and C-peptide 71.8 ng/mL; imaging revealed hepatic tumor progression. Severe hypoglycemia as low as 34 mg/dL was noted despite therapy with IV dextrose (30%, up to 100 cc/hr), glucagon infusion (0.6 mg/hr), dexamethasone 20 mg QD, and diazoxide 30 mg TID. Debilitating anasarca developed despite aggressive diuresis, attributed to high-volume IV dextrose, diazoxide, and renal dysfunction. Two hours after 300 mg alpelisib administration, patient exhibited hyperglycemia, allowing discontinuation of dextrose infusion 8 hours later. Glucagon infusion was subsequently discontinued, and he was discharged to home. Within 20 days, the patient was able to discontinue all diuretics, dexamethasone, and cornstarch. Patient had no side effects related to alpelisib and performance status returned to baseline. Glucose ranged between 160-300 mg/dL without any hypoglycemia. On week 4 of alpelisib, plasma glucose was 340 mg/dL, proinsulin >700 pmol/L, insulin 181 uIU/mL, and C-peptide 20.2 ng/mL. Conclusion: To our knowledge, this is the first case demonstrating alpelisib as a safe and effective option in refractory hypoglycemia associated with insulinoma. While it is unclear whether this is mediated by anti-tumor effects or solely by blockade of insulin action, PI3-K inhibition should be considered as a treatment option in patients with ISPNET in whom hypoglycemia has failed to improve with conventional approaches. Presentation: Friday, June 16, 2023

THU259 Alpelisib-induced Diabetic Ketoacidosis: Call For A Multidisciplinary Approach

Abstract Disclosure: N. Kalara: None. P. Rios: None. F. Vendrame: None. Introduction: Alpelisib is a p110a subunit phosphatidylinositol-3kinase inhibitor (PI3K) approved for treating hormone receptor-positive, human epidermal growth factor receptor 2-negative, PIK3CA mutated, advanced or metastatic breast cancer. PI3K signaling is essential for the metabolic action of insulin and the inhibition of p110a subunit is associated with hyperinsulinemia and hyperglycemia. In the combination (Alpelisib-Fulvestrant) arm of phase III SOLAR-1 study the all-grade incidence of hyperglycemia was 63%, but diabetic ketoacidosis (DKA) was also observed and reported in 0.7% of patients. To the best of our knowledge, less than 10 cases of Alpelisib-induced DKA have been reported in the literature. Here we describe an additional case. Case Description: A 62-year-old female with a history of metastatic breast cancer, hypertension, and prediabetes, presented with 3 days of nausea, vomiting, abdominal pain, weakness, polyuria, and polydipsia. Fifteen days prior to the presentation the HbA1c was 6.1% for which she was started on metformin 500 mg daily. Alpelisib 150 mg PO BID and Fluvestrant (Estrogen receptor antagonist) were also started the same day. The patient was told to stop the PIK3 inhibitor if the blood glucose increased above 200 mg/dL. The review of system was positive for fatigue, decreased appetite, malaise, 5 lbs weight loss during the previous week, and headache. She had no family history of any endocrinologic disease. The physical exam was unremarkable with no signs of insulin resistance. Laboratory tests revealed pH 7.31 (7.35-7.45), HCO3 10 mmol/L (22-26), PCO2 21 mmHg (35-45), glucose 884 mg/dL (74-106), sodium 120 mmol/L (136-145), K 5.2 mmol/L (3.5-5.1), Cl 93 mmol/L (98-107), CO2 7 mmol/L (21-32), anion gap 22 mmol/L (5-15), GFR 30 mL/min/1.73m2 (>60), Cr 1.80 mg/dL (0.5-1.02), BUN 43 mg/dL (7-18), beta-hydroxybutyrate 3 mmol/L (0.4-0.5), HbA1c 9.2% (4.2-5.6). Additional testing revealed C-peptide 2.3 ng/ml (1.1-4.4) with glucose 397 mg/dL. Results suggested a combined DKA and hyperosmolar hyperglycemic state (HHS). Alpelisib was discontinued and the patient was managed with insulin drip, fluids, electrolyte replacement, and eventually transitioned to a basal-bolus regimen (0.5U/kg). The patient was discharged on metformin and Insulin glargine with the recommendation to follow up with endocrinology and oncology. Conclusion: Our case highlights the importance of blood glucose and HbA1c screening before starting Alpelisib with emphasis on a multidisciplinary approach to monitor blood glucose levels to prevent DKA. Reference: 1. Farah SJ, Masri N, Ghanem H, Azar M. Diabetic ketoacidosis associated with alpelisib treatment of metastatic breast cancer. AACE Clin Case Rep. 2020;6(6):e349-e351. doi: 10.4158/ACCR-2020-0452 Presentation: Thursday, June 15, 2023

Piperlongumine induces apoptosis and autophagy via the PI3K/Akt/mTOR pathway in KB human cervical cancer cells.

Natural products are continuously being researched to develop safe and effective treatment options for cervical cancer, the fourth most common cancer in women. Piperlongumine (PL), an amide alkaloid mainly present in long pepper, exhibits neuroprotective and anti-cancer properties. However, the specific effect of PL in cervical cancer and the relationship between the anti-cancer pathway and autophagy remain unclear. Therefore, we aimed to investigate PL-induced apoptosis in KB human cervical cancer cells and the relationship between apoptosis and autophagy therein. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and wound-healing assays showed that PL treatment suppressed KB cell viability and proliferation. Apoptosis was identified through 4',6-diamidino-2-phenylindole and annexin V-propidium iodide staining, increased cleaved-poly (ADP-ribose) polymerase and Bcl-2 associated X levels, and decreased B cell lymphoma 2 levels. Acridine orange staining and increased microtubule-associated protein 1A/1B-light chain 3-II and Beclin-1 levels confirmed autophagy. We determined that KB cell-related autophagy exerted cytoprotective effects using the autophagy inhibitors 3-methyladenine and hydroxychloroquine. PL treatment promoted apoptosis by inhibiting the phosphatidylinositol-3-kinase (PI3K)/protein kinase B/mammalian target of rapamycin pathway in KB cells; inhibiting the pathway using PI3K inhibitors increased autophagy. We suggest that PL is a potential natural anticancer agent for cervical cancer treatment.

Toxic manifestations of alpelisib in endocrinology. Description of the clinical case

Breast cancer (BC) is a serious disease and is considered an important health problem worldwide. The prevalence of the disease in women according to Rosstat was 64,951 cases in the Russian Federation in 2020 (21.7% among all types of cancer). Hormone-dependent estrogen receptor-positive (HR+), human epidermal growth factor receptor type 2 negative (HER2-) metastatic breast cancer (mBC) accounts for 70% of all cases. About 40% of patients with ER+/HER2- mBC have mutations in the PIK3CA gene, leading to hyperactivation of the alpha isoform (p110α) of phosphatidylinositol 3-kinase (PI3K). Hormonal therapy with or without cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor is considered the standard treatment for patients with ER+/HER2- mBC. However, acquired resistance to this therapy remains a problem. Innovative methods for the treatment of breast cancer are the use of targeted therapeutic agents aimed at direct inhibition of the PI3K pathway in combination with hormone therapy. Alpelisib is a PI3Kα-specific inhibitor. Hyperglycemia is the most common side effect of alpelisib treatment. Currently, there is a consensus on the prevention and correction of hyperglycemia in patients receiving therapy with alpelisib, which recommends that before starting therapy, in order to diagnose carbohydrate metabolism disorders and assess the risk of developing hyperglycemia, determine in all patients: the level of glycated hemoglobin (HbA1c), glucose fasting plasma (FPG), body mass index (BMI). And also to evaluate such risk factors as the presence of a family history of type 2 diabetes mellitus (DM 2), the presence of gestational diabetes in the patient's history, or the fact of the birth of children weighing more than 4 kilograms.Recently, new combinations of drugs have been actively used to treat disorders of carbohydrate metabolism, such as pioglitazone + metformin. This paper discusses the mechanism of action of PI3K inhibitors, new therapeutic combinations and their undesirable effects, and presents therapeutic experience.

Resveratrol inhibits basic fibroblast growth factor-induced macrophage colony-stimulating factor synthesis via the PI3-kinase/Akt pathway in osteoblasts.

Resveratrol is a natural polyphenol found in grapes and beneficial for human health. Resveratrol regulates basic fibroblast growth factor (bFGF)-induced osteoprotegerin synthesis through Akt pathway in osteoblast-like MC3T3-E1 cells. In this study, we investigated resveratrol effects on bFGF-induced macrophage colony-stimulating factor (M-CSF) synthesis in MC3T3-E1 cells. bFGF significantly stimulated release and mRNA expression of M-CSF, which was reduced by resveratrol and SRT1720, sirtuin 1 (SIRT1) activator. Inauhzin, SIRT1 inhibitor, reversed inhibitory effects of resveratrol on bFGF-induced mRNA expression of M-CSF. Deguelin, Akt inhibitor, and LY294002, phosphatidylinositol 3-kinase (PI3-kinase) inhibitor, reduced bFGF-induced M-CSF synthesis. Inauhzin reversed inhibitory effects of resveratrol on bFGF-induced Akt phosphorylation. Suppressive effect of resveratrol on bFGF-induced osteoprotegerin mRNA expression was confirmed in the identical samples using in experiment of M-CSF mRNA expression. Therefore, resveratrol reduces bFGF-induced M-CSF synthesis in addition to osteoprotegerin synthesis by inhibiting PI3-kinase/Akt pathway and suppressive effects are mediated through SIRT1 activation in osteoblasts.

Elucidating the Morphogenic and Signaling Roles of Defined Growth Factors Controlling Human Endothelial Cell Lumen Formation Versus Sprouting Behavior

Five growth factors [ie, insulin, fibroblast growth factor-2 (FGF-2), stem cell factor, IL-3, and stromal-derived factor 1α] in combination are necessary for human endothelial cells (ECs) to undergo tube morphogenesis, a process requiring both lumen formation and sprouting behavior. This study investigated why these factors are required by subdividing the factors into 4 separate groups: insulin-only, insulinand FGF-2, no FGF-2 (all factors but without FGF-2), and all factors. The study found that the insulin-only condition failed to support EC morphogenesis or survival, the insulinand FGF-2 condition supported primarily EC lumen formation, and the no FGF-2 condition supported EC sprouting behavior. By comparison, the all-factors condition more strongly stimulated both EC lumen formation and sprouting behavior, and signaling analysis revealed prolonged stimulation of multiple promorphogenic signals coupled with inhibition of proregressive signals. Pharmacologic inhibition of Jak kinases more selectively blocked EC sprouting behavior, whereas inhibition of Raf, phosphatidylinositol 3-kinase, and Akt kinases showed selective blockade of lumen formation. Inhibition of Src family kinases and Notch led to increased sprouting coupled to decreased lumen formation, whereas inhibition of Pak, Mek, and mammalian target of rapamycin kinases blocked both sprouting and lumen formation. These findings reveal novel downstream biological and signaling activities of defined factors that are required for the assembly of human EC-lined capillary tube networks.

Theabrownin from Dark Tea Ameliorates Insulin Resistance via Attenuating Oxidative Stress and Modulating IRS-1/PI3K/Akt Pathway in HepG2 Cells.

Dark tea has great potential in regulating glycolipid metabolism, and theabrownin (TB) is considered to be the characteristic and bioactive constituent of dark tea. This study evaluated the ability of TB1 (fermented for 7 days) and TB2 (fermented for 14 days) isolated from dark tea to reverse insulin resistance (IR) in HepG2 cells. The results indicated that TB significantly ameliorated oxidative stress by improving mitochondrial function. In addition, TB improved glycogen synthesis and glucose consumption, and inhibited gluconeogenesis and fatty acid synthesis, by regulating GSK3β (Glycogen synthase kinase 3β), G6Pase (Glucose-6-phosphatase), GCK (Glucokinase), PEPCK1 (Phosphoenolpyruvate carboxy kinase 1), SREBP-1C (sterol regulatory element-binding protein 1C), FASN (fatty acid synthase), and ACC (Acetyl-CoA carboxylase). Additionally, the results of Western blot and real-time PCR experiments demonstrated that TB modulated glucolipid metabolism through the IRS-1 (Insulin receptor substrate 1)/PI3K (phosphatidylinositol-3 kinase)/Akt (protein kinase B) signaling pathway. Treatment with the PI3K inhibitor demonstrated a favorable correlation between PI3K activation and TB action on glycolipid metabolism. Notably, we observed that TB2 had a greater effect on improving insulin resistance compared with TB1, which, due to its prolonged fermentation time, increased the degree of oxidative polymerization of TB.

Rationally designed chimeric PI3K-BET bromodomain inhibitors elicit curative responses in MYC-driven lymphoma

Targeted inhibitors of bromodomain and extraterminal (BET)-bromodomains and phosphatidylinositol-3-kinase (PI3K) signaling demonstrate potent but self-limited antilymphoma activity as single agents in the context of cellular Myelocytomatosis (cMYC) oncogene-dysregulation. However, combined PI3K and BET inhibition imparts synergistic anticancer activity with the potential for more sustained disease responses due to the mutual antagonism of compensatory epigenetic and signaling networks. Here, we describe the mechanistic and therapeutic validation of rationally designed dual PI3K/BET bromodomain inhibitors, built by linkage of established PI3K and BET inhibitor pharmacophores. The lead candidate demonstrates high selectivity, nanomolar range cellular potency, and compelling in vivo efficacy, including curative responses in the aggressive Eµ-Myc lymphoma model. These studies further support the therapeutic strategy of combined PI3K and BET inhibition and provide a potential step-change in approach to orthogonal MYC antagonism using optimized chimeric small-molecule technology.

Design, synthesis, and biological evaluation of novel bivalent PI3K inhibitors for the potential treatment of cancer

Phosphatidylinositol 3-kinase (PI3K) signaling is among the most common alterations in cancer and has become a key target for cancer drug development. Based on a 4-methyl quinazoline scaffold, we designed and synthesized a novel series of bivalent PI3K inhibitors with different linker lengths and types. Bivalent PI3K inhibitor 27 demonstrates improved PI3K potency and antiproliferative cell activity, relative to the corresponding monovalent inhibitor 11. Compound 27 also significantly blocks the PI3K signal pathway, induces cell cycle arrest in G1 phase, and inhibits colony formation and cell migration. Furthermore, compound 27 shows dose-dependent anticancer efficacies in a HGC-27 xenograft mice model. Overall, this work provides a possible strategy to discover novel PI3K inhibitors for the treatment of cancers.

PI3K block restores age-dependent neurovascular coupling defects associated with cerebral small vessel disease

Neurovascular coupling (NVC), a vital physiological process that rapidly and precisely directs localized blood flow to the most active regions of the brain, is accomplished in part by the vast network of cerebral capillaries acting as a sensory web capable of detecting increases in neuronal activity and orchestrating the dilation of upstream parenchymal arterioles. Here, we report a Col4a1 mutant mouse model of cerebral small vessel disease (cSVD) with age-dependent defects in capillary-to-arteriole dilation, functional hyperemia in the brain, and memory. The fundamental defect in aged mutant animals was the depletion of the minor membrane phospholipid phosphatidylinositol 4,5 bisphosphate (PIP2) in brain capillary endothelial cells, leading to the loss of inwardly rectifying K+ (Kir2.1) channel activity. Blocking phosphatidylinositol-3-kinase (PI3K), an enzyme that diminishes the bioavailability of PIP2 by converting it to phosphatidylinositol (3, 4, 5)-trisphosphate (PIP3), restored Kir2.1 channel activity, capillary-to-arteriole dilation, and functional hyperemia. In longitudinal studies, chronic PI3K inhibition also improved the memory function of aged Col4a1 mutant mice. Our data suggest that PI3K inhibition is a viable therapeutic strategy for treating defective NVC and cognitive impairment associated with cSVD.

CD73 mitigates hepatic damage in alcoholic steatohepatitis by regulating PI3K/AKT-mediated hepatocyte pyroptosis

BackgroundAlcohol use is a major risk factor for death and disability, resulting in a significant global disease burden. Alcoholic steatohepatitis (ASH) reflects an acute exacerbation of alcoholic liver disease (ALD) and is a growing health care and economic burden worldwide. Pyroptosis plays a central role in the pathogenesis of ASH. Nt5e (CD73) is a cell surface ecto-5ʹ-nucleotidase, which is a key enzyme that converts the proinflammatory signal ATP to the anti-inflammatory mediator adenosine (ADO). Studies have found that CD73 is involved in multiple diseases and can alleviate gasdermin D (GSDMD)-mediated pyroptosis; however, its role and mechanism in ASH are not explicit. AimTo investigate the role and mechanisms of CD73-mediated hepatocyte pyroptosis in alcohol-induced liver injury through in vivo and in vitro experiments. MethodsCD73 knockout (CD73-/-) mice, wild-type (WT) mice, and AML-12 cells were used to evaluate the effect of CD73 on hepatocyte pyroptosis in vivo and in vitro. A combination of molecular and histological methods was performed to assess pyroptosis and investigate the mechanism both in vivo and in vitro. ResultsThe protein expression of CD73 and pyroptosis pathway-associated genes was increased significantly in hepatocyte injury model both in vivo and in vitro. In vivo, CD73 knockout dramatically aggravated inflammatory damage, lipid accumulation, and hepatocyte pyroptosis in the liver. In vitro, overexpression of CD73 by pEGFP-C1/CD73 can decrease NLRP3 inflammasome activation and pyroptosis in hepatocytes. Further analysis revealed that the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway is a possible mechanism of CD73 regulation. Meanwhile, this pathological process was inhibited after the use of PI3K inhibitors. ConclusionOur results show a novel function of CD73 regulates hepatocytes pyroptosis and highlights the therapeutic opportunity for reducing the disease process in ALD.

The Potent and Selective Histamine H3 Receptor Antagonist E169 Counteracts Cognitive Deficits and Mitigates Disturbances in the PI3K/AKT/GSK-3β Signaling Pathway in MK801-Induced Amnesia in Mice.

The role of histamine H3 receptors (H3Rs) in memory and the prospective of H3R antagonists in pharmacological control of neurodegenerative disorders, e.g., Alzheimer's disease (AD), is well-accepted. Therefore, the procognitive effects of acute systemic administration of H3R antagonist E169 (2.5-10 mg/kg, i.p.) on MK801-induced amnesia in C57BL/6J mice using the novel object recognition test (NORT) were evaluated. E169 (5 mg) provided a significant memory-improving effect on MK801-induced short- and long-term memory impairments in NORT. The E169 (5 mg)-provided effects were comparable to those observed with the reference phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 and were abrogated with the H3R agonist (R)-α-methylhistamine (RAMH). Additionally, our results demonstrate that E169 ameliorated MK801-induced memory deficits by antagonism of H3Rs and by modulation of the level of disturbance in the expression of PI3K, Akt, and GSK-3β proteins, signifying that E169 mitigated the Akt-mTOR signaling pathway in the hippocampus of tested mice. Moreover, the results observed revealed that E169 (2.5-10 mg/kg, i.p.) did not alter anxiety levels and locomotor activity of animals in open field tests, demonstrating that performances improved following acute systemic administration with E169 in NORT are unrelated to changes in emotional response or in spontaneous locomotor activity. In summary, these obtained results suggest the potential of H3R antagonists such as E169, with good in silico physicochemical properties and stable retained key interactions in docking studies at H3R, in simultaneously modulating disturbed brain neurotransmitters and the imbalanced Akt-mTOR signaling pathway related to neurodegenerative disorders, e.g., AD.

Mitigation of acetaminophen-induced liver toxicity by the novel phosphatidylinositol 3-kinase inhibitor alpelisib.

The sterile inflammatory response mediated by Toll-like receptors (TLRs) 4 and 9 is implicated in the massive hepatic damage caused by acetaminophen (APAP)-overdose. There is a crosstalk between TLR-dependent signaling with other intracellular kinases like phosphatidylinositol 3-kinases (PI3Ks). Nevertheless, the detailed role of PI3Kα is still unknown in hepatic sterile inflammation. Accordingly, the effect of the novel PI3Kα inhibitor alpelisib was investigated in the setting of APAP-driven sterile inflammation in the liver. This was examined by pretreating mice with alpelisib (5 and 10mg/kg, oral) 2h before APAP (500mg/kg, i.p.)-intoxication. The results indicated that alpelisib dose-dependently lowered APAP-induced escalation in serum liver function biomarkers and hepatic necroinflammation score. Alpelisib also attenuated APAP-induced rise in cleaved caspase 3 and proliferating cell nuclear antigen (PCNA) in the liver hepatocytes, as indices for apoptosis and proliferation. Mechanistically, inhibition of PI3Kα by alpelisib limited APAP-induced overproduction of the pro-inflammatory tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 in the blood circulation via switching off the activation of several signal transduction proteins, including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), signal transducer and activator of transcription-3 (Stat-3), glycogen Synthase Kinase (GSK)-3β and nuclear factor (NF)-κB. Alpelisib also impaired APAP-instigated immune cell infiltration in the liver via reducing systemic granulocyte/macrophage-colony stimulating factor (GM-CSF) release and reversed APAP-induced abnormalities in the systemic and hepatic levels of the anti-inflammatory IL-10 and IL-22. In conclusion, selective modulation of the PI3Kα activity by alpelisib can hinder the inflammatory response and infiltration of immune cells occurring by APAP-hepatotoxicity.

FGF21 promotes myocardial angiogenesis and mediates the cardioprotective effects of exercise in myocardial infarction mice.

The mechanism by which aerobic exercise promotes cardiac function after myocardial infarction (MI) is still not fully understand. In this study, we investigated the role of fibroblast growth factor 21 (FGF21) in exercise protecting the cardiac function of MI mice. In vivo, MI was induced by left anterior descending coronary artery ligation in wild-type and fgf21 knockout mice on the C57BL/6 background. One week after MI, the mice underwent aerobic exercise for 4 wk. In vitro, human umbilical vein endothelial cells (HUVECs) were treated with H2O2, recombinant human FGF21 (rhFGF21), fibroblast growth factor receptor 1 (FGFR1) inhibitor (PD166866), and phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002) to explore the potential mechanisms. Scratch wound healing and tubule formation analysis were used to detect the migration and tubule formation ability of HUVECs. Our results showed that aerobic exercise significantly promoted angiogenesis and cardiac function through enhancing the expression of FGF21 and activating FGFR1/PI3K/AKT/VEGF pathway. But such changes in cardiac from aerobic exercise were attenuated by fgf21 knockout mice. 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) enhanced angiogenesis and cell migration through FGF21/FGFR1/PI3K/AKT/VEGF signaling pathway. Under the intervention of H2O2, rhFGF21 also played the role of promoting angiogenesis and cell migration through the same mechanism. In conclusion, our results showed that FGF21 promoted the aerobic exercise-induced angiogenesis and improved cardiac function via FGFR1/PI3K/AKT/VEGF signal in MI mice.NEW & NOTEWORTHY FGF21 activated FGFR1/PI3K/AKT/VEGF signaling pathway mediated angiogenesis in MI mice. FGF21 deficiency attenuated aerobic exercise-induced cardiac angiogenesis in MI mice. FGF21/FGFR1/PI3K/AKT/VEGF signal played an important role in aerobic exercise to promote myocardial angiogenesis and improved cardiac function.

Calcium handling coupled to the endothelin ETA and ETB receptor-mediated vasoconstriction in resistance arteries: Differential regulation by PI3K, PKC and RhoK

Abnormal endothelin-1 (ET-1) activity is involved in the pathogenesis of vascular diseases such as essential and pulmonary arterial hypertension, coronary artery disease, and cerebrovascular disease, blockade of ET receptors having shown efficacy in clinical assays and experimental models of hypertension. Augmented Ca2+ influx and changes in Ca2+ sensitization associated with arterial vasoconstriction underlie increased systemic vascular resistance in hypertension. Since peripheral resistance arteries play a key role in blood pressure regulation, we aimed to determine here the specific Ca2+ signaling mechanisms linked to the ET receptor-mediated vasoconstriction in resistance arteries and their selective regulation by protein kinase C (PKC), Rho kinase (RhoK), the phosphatidylinositol 3-kinase (PI3K) and the mitogen-activated protein kinase (MAPK). ET-1-induced contraction was mediated by the endothelin ETA receptor with a minor contribution of vascular smooth muscle (VSM) endothelin ETB receptors. ET receptor activation elicited Ca2+ mobilization from intracellular stores, extracellular Ca2+ influx and Ca2+ sensitization associated with contraction in resistance arteries. Vasoconstriction induced by ET-1 was largely dependent on activation of canonical transient receptor potential channel 3 (TRPC3) and extracellular Ca2+ influx through nifedipine-sensitive voltage-dependent Ca2+ channels. PI3K inhibition reduced intracellular Ca2+ mobilization and Ca2+ entry without altering vasoconstriction elicited by ET-1, while PKC has dual opposite actions by enhancing Ca2+ influx associated with contraction, and by inhibiting Ca2+ release from intracellular stores. RhoK was a major determinant of the enhanced sensitivity of the contractile filaments underlying ET-1 vasoconstriction, with also a modulatory positive action on Ca2+ influx and intracellular Ca2+ release. Augmented RhoK and PKC activities are involved in vascular dysfunction in hypertension and vascular complications of insulin-resistant states, and these kinases are thus potential pharmacological targets in vascular diseases in which the ET pathway is impaired.

Neuroprotective effect of salidroside on hippocampal neurons in diabetic mice via PI3K/Akt/GSK-3β signaling pathway.

Diabetic encephalopathy is manifested by cognitive dysfunction. Salidroside, a nature compound isolated from Rhodiola rosea L, has the effects of anti-inflammatory and antioxidant, hypoglycemic and lipid-lowering, improving insulin resistance, inhibiting cell apoptosis, and protecting neurons. However, the mechanism by which salidroside alleviates neuronal degeneration and improves learning and memory impairment in diabetic mice remains unclear. To investigate the effects and mechanisms of salidroside on hippocampal neurons in streptozotocin-induced diabetic mice. C57BL/6 mice were randomly divided into 4 groups to receive either sham (control group (CON)), diabetes mellitus (diabetes group (DM)), diabetes mellitus + salidroside (salidroside group (DM + SAL)), and diabetes mellitus + salidroside + phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 (diabetes mellitus + salidroside + LY294002 group (DM + SAL + LY294002)). After 12weeks of diabetes onset, the cognitive behaviors were tested using Morris water maze. The number of hippocampal neurons was detected by Nissl staining. The expressions of PI3K, p-PI3K, Akt, p-Akt, GSK-3β, p-GSK-3β, cleaved caspase-3, caspase-3, Bax, Bcl-2, MAP2, and SYN in the hippocampus were detected by Western blot. Moreover, the expression of MAP2 and SYN in the hippocampus was further confirmed by immunofluorescence staining. Salidroside increased the time of diabetic mice in the platform quadrant and reduced the escape latency of diabetic mice. Salidroside also increased the expression of p-PI3K, p-Akt, p-GSK-3β, MAP2, SYN, Bcl-2, while suppressed the expression of cleaved caspase-3, caspase3, and Bax in the DM + SAL group compared with the DM group (P < 0.05). The Nissl staining showed thatthe number of hippocampus neurons in the DM + SAL group was increased with the intact, compact, and regular arrangement, compared with the DM groups (P < 0.05). Interestingly, the protective effects of salidroside on diabetic cognitive dysfunction, hippocampal morphological alterations, and protein expressions were abolished by inhibition of PI3K with LY294002. Salidroside exerts neuroprotective properties in diabetic cognitive dysfunction partly via activating the PI3K/Akt/GSK-3β signaling pathway.

A Biomimetic Peptide Functions as Specific Extracellular Matrix for Quiescence of Stem Cells against Intervertebral Disc Degeneration.

Maintaining quiescence of stem cells is a potential way to decrease cell nutrition demand for restoring the organization. Herein, a biomimetic peptide to maintain quiescence of stem cells through C-X-C motif chemokine ligand 8 (CXCL8)-C-X-C motif chemokine receptor 1 (CXCR1) pathway against intervertebral disc degeneration (IVDD)is developed. First, it is confirmed that quiescence can be induced via inhibiting phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway in nucleus pulposus stem cells (NPSCs). Meanwhile, it is well known that CXCR1, a chemokine receptor, can be targeted by CXCL8, resulting in cell proliferation via activating PI3K/Akt/mTOR pathway. Second, a biomimetic peptide (OAFF) that can bind to CXCR1 and form fibrous networks on NPSCs, mimicking extracellular matrix formation is developed. The multivalent effect and long-term binding to CXCR1 on NPSCs of OAFF fibers offer forcefully competitive inhibition with natural CXCL8, which induces NPSCs quiescence and ultimately overcomes obstacle in intradiscal injection therapy. In rat caudal disc puncture model, OAFF nanofibers still maintain at 5 weeks after operation and inhibit degeneration process of intervertebral disc in terms of histopathology and imageology. In situ fibrillogenesis of biomimetic peptide on NPSCs provides promising stem cells for intradiscal injection therapy against IVDD.

Design, synthesis, anticancer evaluation, and in silico studies of some thieno[2,3-d]pyrimidine derivatives as EGFR inhibitors.

New series of 20 thieno[2,3-d]pyrimidine derivatives have been synthesized. The National Cancer Institute evaluated all the newly synthesized compounds for their antiproliferative activity against a panel of 60 cancer cell lines. Compound 7b exhibited a remarkable antineoplastic activity at 10 µM dose and was therefore tested at five dose concentrations. The significant and broad-spectrum antineoplastic action of compound 7b was observed against 37 of the tested cancer cell lines with a dose that inhibits 50% of the growth compared to control values in the micromolar range of 1.95-9.6 µM. The dose which inhibits the growth completely in the cytostatic range of 3.99-100 µM was also observed. Compound 7b effectively inhibited epidermal growth factor receptor (EGFR) with 50% inhibition concentration value (IC50 ) = 0.096 ± 0.004 compared to erlotinib with IC50 = 0.037 ± 0.002. Moreover, compound 7b revealed a powerful downregulation effect on total EGFR concentration and its phosphorylation. In addition, compound 7b inhibited phosphatidylinositol 3-kinase, protein kinase B, and the mammalian target of rapamycin pathway phosphorylation. Furthermore, compound 7b raised total apoptosis by 21.93-fold in the ovarian cancer cell line (OVCAR-4) and caused an arrest in the cell cycle in the G1/S phase. It also raised the level of caspase-3 by 4.72-fold. Furthermore, to determine the binding manner of the most effective derivatives and validate their capacity to comply with the pharmacophoric properties necessary for EGFR inhibition, they were docked into the active site of the EGFR.

Role of KLF4/NDRG1/DRP1 axis in hypoxia-induced pulmonary hypertension

N-myc downstream regulated gene 1 (NDRG1) has recently drawn increasing attention because of its involvement in angiogenesis, cell proliferation, and differentiation. We used in vitro [human pulmonary artery smooth muscle cells (hPASMCs)] and in vivo (rat) models under hypoxic conditions and found a vital role of NDRG1 in reducing apoptosis and increasing proliferation and migration by overexpressing and knocking down NDRG1. We also proved that hypoxia induced the protein expression of dynamin-related protein 1 (DRP1) and stimulated The phosphatidylinositol-3-kinase (PI3K)/ Protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathways, and these effects were reversed by NDRG1 knockdown. The relationship between NDRG1 and DRP1 and the PI3K/Akt/mTOR pathway was further evaluated by adding mdivi-1 (DRP1 inhibitor) or LY294002 (PI3K inhibitor). NDRG1 was found to regulate the proliferation, apoptosis, and migration of hypoxia-treated hPASMCs via DRP1 and PI3K/Akt/mTOR signaling pathways. We explored the upstream regulators of NDRG1 using in vivo and in vitro hypoxia models. Hypoxia was found to upregulate and downregulate KLF transcription factor 4 (KLF4) protein expression in the cytoplasm and nucleus, respectively. Further, we showed that KLF4 regulated the proliferation and migration of hypoxia-treated hPASMCs via NDRG1. These results indicated a link between KLF4, NDRG1, and DRP1 for the first time, providing new ideas for treating hypoxic pulmonary hypertension.

A dahlia flower extract has antidiabetic properties by improving insulin function in the brain

Abstract Butein, a rare chalcone found in the toxic plant Toxicodendron vernicifluum, has been shown to regulate glucose homeostasis via inhibition of the nuclear factor kappa-B kinase subunit beta (IKKβ)/nuclear factor kappa B (NF-κB) pathway in the brain. Here, we investigated whether the nonpoisonous plant Dahlia pinnata could be a source of butein as a potential treatment for type 2 diabetes (T2D). In mice fed a high-fat diet (HFD) to induce glucose intolerance, an oral D. pinnata petal extract improved glucose tolerance at doses of 3.3 mg/kg body weight and 10 mg/kg body weight. Surprisingly, this effect was not mediated by butein alone but by butein combined with the closely related flavonoids, sulfuretin and/or isoliquiritigenin. Mechanistically, the extract improved systemic insulin tolerance. Inhibition of phosphatidylinositol 3-kinase to block insulin signaling in the brain abrogated the glucoregulatory effect of the orally administered extract. The extract reinstated central insulin signaling and normalized astrogliosis in the hypothalamus of HFD-fed mice. Using NF-κB reporter zebrafish to determine IKKβ/NF-κB activity, a potent anti-inflammatory action of the extract was found. A randomized controlled crossover clinical trial on participants with prediabetes or T2D confirmed the safety and efficacy of the extract in humans. In conclusion, we identified an extract from the flower petals of D. pinnata as a novel treatment option for T2D, potentially targeting the central regulation of glucose homeostasis as a root cause of the disease.