Expression Of Phosphoinositide 3-kinase Research Articles

In vitro and in vivo anti-malignant melanoma activity of Alocasia cucullata via modulation of the phosphatase and tensin homolog/phosphoinositide 3-kinase/AKT pathway

Alocasia cucullata, a Chinese herb, has been used as an anticancer treatment in southern China. Phosphatase and tensin (PTEN), is a tumor suppressor gene and the loss of PTEN expression may activate the phosphoinositide-3-kinase (PI3K)/AKT signaling pathway which play a key role in tumors formation and progression. In this study, we evaluated the anti-melanoma effect and the underlying mechanism of 50% ethanolic extract of A. cucullata (EAC) in vitro and in vivo. Using MTT, wound healing, and transwell assays, we found that EAC suppressed the proliferation, migration, and invasion of melanoma cells (B16-F10, A375 and A2058) in a dose-dependent manner. We also found that EAC suppresses B16-F10 tumor growth in a xenografted mouse model. Western blot analysis revealed that the expression level of PTEN was up-regulated, and phosphorylation of PI3K and AKT reduced in B16-F10 cells and tumor tissues after EAC treatment. No significant differences were observed in PI3K and AKT expression. Moreover, immunohistochemistry showed that the number of PTEN-positive cells in tumor tissues increased and that of p-AKT-positive cells decreased with EAC treatment, corroborating the western blot results. Our data reveal that EAC can inhibit malignant melanoma in vitro and in vivo and suggest that its anti-tumor effect is associated with modulation of the PTEN/ PI3K/AKT signaling pathway. In summary, our findings highlight a promising herbal remedy for the treatment of malignant melanoma, which warrants further study.

Virosecurinine induces apoptosis in human leukemia THP-1 cells and other underlying molecular mechanisms.

Virosecurinine, a primary alkaloid from Securinega suffruticosa plant is known as a potent differentiation-inducing agent in acute leukemia cells. The present study aimed to investigate the effects and underlying mechanisms of virosecurinine on human leukemia THP-1 cells in vitro. The effects of virosecurinine on cell proliferation were assessed by CCK-8. The effects on apoptosis and cell cycle were assessed by staining with annexin V-fluorescein isothiocyanate and propidium iodide, respectively followed by flow cytometric analysis. The apoptotic cell bodies were observed using a transmission electron microscope, while the mRNA expression of phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), mechanistic target of rapamycin (mTOR) and phosphatase and tensin homolog (PTEN) in THP-1 was evaluated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Treatment with virosecurinine was able to decrease the viability of THP-1 cells in a dose- and time-dependent manner. The IC50 values of virosecurinine at 24, 48, and 72 h post-treatment were 68.128, 23.615, and 13.423 µmol/l, respectively. Cell cycle was arrested at the G1/S phase in virosecurinine-treated cells; however, not in untreated control cells. Numerous apoptotic bodies were observed in the THP-1 cells, which were treated with 12.5 µmol/l virosecurinine for 48 h. RT-qPCR indicated that treatment with virosecurinine resulted in upregulated PTEN expression and downregulated expression of PI3K, AKT and mTOR in THP-1 cells. The present study demonstrated that treatment with virosecurinine was able to inhibit proliferation and induce apoptosis in THP-1cells by exerting an inhibitory effect on the activation of PI3K/AKT/mTOR signaling pathways. Therefore, our data suggested that virosecurinine is a promising anti-tumor agent for the treatment of acute monocytic leukemia.

Geniposide attenuates epilepsy symptoms in a mouse model through the PI3K/Akt/GSK-3β signaling pathway.

Previous reports on the pharmacological actions of geniposide have indicated that it has anti-asthmatic, anti-inflammatory and analgesic effects in the liver and gallbladder, and therapeutic effects in neurological, cardiovascular and cerebrovascular diseases. The results of the current study demonstrate that geniposide attenuates epilepsy in a mouse model through the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) signaling pathway. A mouse model of epilepsy was induced by maximal electric shock (50 mA, 50 Hz, 1 sec). Epilepsy mice were intragastrically administered with 0, 5, 10 or 20 mg/kg geniposide. Geniposide significantly reduced the incidence and significantly increased the latency of clonic seizures in epileptic mice compared with non-treated epileptic mice (both P<0.01). Geniposide treatment significantly inhibited cyclooxygenase-2 mRNA expression in epilepsy mice (P<0.01). Furthermore, geniposide significantly suppressed the protein expression of activator protein 1, increased the activation of Akt and increased the protein expression of GSK-3β and PI3K in epilepsy mice (all P<0.01). These results suggest that geniposide attenuates epilepsy in mice through the PI3K/Akt/GSK-3β signaling pathway.

OP.8B.05] TRANSGENERATIONAL INHERITANCE OF OBESITY AND HYPERTENSION

Objective: Maternal obesity increases the risk of developing hypertension in the offspring. Circulating leptin is closely linked to the control of sympathetic nerve activity (SNA) and blood pressure (BP) in the central nerve system. The ventromedial hypothalamus (VMH) is a key center of energy homeostasis, hemodynamic and sympathetic tone to renal vasculature. Exposure to overnutrition during early development changes the activity of the neurons and the receptors in the CNS, amplifying sympathetic output which leads to hypertension. We assessed the effects of maternal high fat diet (HFD) feeding during pregnancy on cardiovascular variables and sympathetic nerve activity (SNA) with changes in leptin and insulin signaling pathways in adulthood. Design and method: Breeder rabbits were fed a HFD (13%; HFD) or a control diet (4%; CD) during pregnancy and lactation. Offspring received CD after weaning. All rabbits had a VMH cannula and a renal nerve recording electrode. Mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA) were measured at baseline and after receiving increasing doses of αMSH (α-Melanocortin stimulating hormone, 0.3, 1nmol), SHU9119 (melanocortin receptor antagonist, 0.02, 0.04nmol), leptin receptor antagonist (5, 10 μg) or insulin receptor antagonist (0.01, 0.05U). Hypothalamic expression of leptin receptor (LepR) and Phosphoinositide 3-kinase (PI3K) was examined using real-time PCR. Results: Offspring from HFD fed rabbits (mHFD) showed higher MAP (+11%) and RSNA (+42%) than controls in adulthood (P < 0.05). αMSH into the VMH increased MAP, HR and RSNA (+6.6 ± 1mmHg, +23.4 ± 3.45 b/min and +3.66 ± 0.7nu) and SHU9119 reduced MAP and RSNA (−5.6 ± 0.8mmHg, −1.3 ± 0.13 nu) in mHFD rabbits. Leptin receptor antagonist normalized hypertension (−5.8 ± 0.8mmHg) in mHFD rabbits (P < 0.05). Insulin receptor antagonist administration into the VMH showed no changes in MAP, HR and RSNA in both mHFD and mCD rabbits. Offspring from maternal HFD rabbits exhibited an increase in LepR and PI3K expression in the hypothalamus compared to the control group (+47% and +74%). Conclusions: Exposure to over-nutrition during early development leads to permanently altered leptin and MC signaling pathways, due to programming of the key receptors and/or by neuronal plasticity, leading to sympathoexcitation and hypertension in adulthood.

226 PIK3CB/p1102 is a Selective Survival Factor for Glioblastoma

Abstract INTRODUCTION PIK3CB is an isoform of phosphoinositide3-kinase (PI3K) shown to be a biomarker for glioblastoma recurrence. We sought to assess the relationship between PIK3CB expression and recurrence and whether it could provide a novel therapeutic target in the treatment of glioblastoma. METHODS We assessed for trends in PI3K expression in glioblastoma patients from the TCGA database. We cultured glioblastoma cell lines and analyzed the expression of PIK3CB/p110ß and its role in AKT activation. Genetic knockdown was utilized to silence PIK3CB/p110ß to evaluate the effect on AKT activation. We inoculated tumor cells into immune deficient mice to form subcutaneous xenograft tumors and then treated mice with TGX-221 which is a p110ß inhibitor. RESULTS &gt;Expression of high levels of PIK3CB showed a statistically significant increase in the incidence of glioblastoma recurrence (P = 0.01), shorted time to tumor recurrence (P = 0.03), and shorter survival after recurrence (P &lt; 0.05). The p110ß isoform of PIK3CB was consistently expressed at high levels which coincided with robust activation of pAKT which is involved in cell survival. We silenced was with shRNA-mediated knockdown and found a 70–80% reduction in p110ß. Silencing PIK3CB/p110ß induced an 80% decrease in pAKT levels and lead to apoptosis. In inoculated mouse studies, TGX-221 significantly decreased the tumor volumes compared to the control (P = 0.029). Tumor growth inhibition (TGI) of TGX-221 was approximately 57. CONCLUSION Higher levels of PIK3CB in glioblastoma are correlated with higher incidence of recurrence, shorter time to recurrence, and worse prognosis of tumor recurrence. Higher levels of PIK3CB/p110ß correlate with phosphorylated AKT levels which is associated with cell survival. TGX-221, a selective inhibitor of PIK3CB/p110ß, suppresses AKT activation and inhibits cell survival and glioblastoma growth. Our results demonstrate that PIK3CB/p110ß is an essential survival factor for glioblastoma, and inhibitors like TGX-221 may serve as adjuncts to treatment.

Suxiao Jiuxin Pill protects cardiomyocytes against mitochondrial injury and alters gene expression during ischemic injury.

Suxiao Jiuxin Pill (SX), a traditional Chinese medicine compound consisting primarily of tetramethylpyrazine and borneol, has been reported to protect against ischemic heart disease. However, the effects of SX on mitochondrial injury and gene expression in various signaling pathways are unclear. The aim of the present study was to investigate the effects of SX on mitochondrial injury and to screen the expression of genes potentially altered by SX using a cell culture model of ischemic injury. Simulated ischemia was established by culturing HL-1 cardiomyocytes in Dulbecco's modified Eagle medium without glucose or serum in a hypoxic chamber containing 95% N2 and 5% CO2 for 24 h. HL-1 cardiomyocytes were divided into 3 groups: Control, ischemic injury and ischemic injury + SX (100 µg/ml; n=3 wells/group). Mitochondrial membrane potential was detected by staining with JC-1 dye. The mRNA expression levels of adenylyl cyclase (Adcy) 1–9, adrenoceptor β1, Akt1, ATPase Na+/K+ transporting subunit β2, calcium voltage-gated channel auxiliary subunit α2δ (Cacna2d)2, Cacna2d3, calcium channel voltage-dependent γ subunit 8, cytochrome C oxidase subunit 6A2 (Cox6a2), fibroblast growth factor receptor (Fgfr) 4, Fgf8, Fgf12, Gnas complex locus, glycogen synthase kinase 3β (Gsk3b), mitogen-activated protein kinase (Mapk)11-14, Mapk kinase kinase kinase 1 (Map4k1), Mas1, nitric oxide synthase 3 (Nos3), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (Pik3ca), phospholipase A2 group 4A, rap guanine nucleotide exchange factor 4 and ryanodine receptor 2 were detected using reverse transcription-quantitative polymerase chain reaction. The protein expression levels of phosphoinositide 3-kinase (PI3K), MAS-1 and phosphorylated-endothelial NOS were also examined by immunofluorescence staining. The decrease in mitochondrial membrane potential in the cell culture model of ischemic injury (P<0.001) was significantly attenuated by SX treatment (P<0.001). Furthermore, increases in the mRNA expression levels of Adcy2 (P<0.05), 3 (P<0.01) and 8 (P<0.05) in the ischemic injury model were significantly attenuated by SX treatment (P<0.01), and SX treatment significantly decreased the mRNA expression levels of Adcy1 (P<0.01) and 6 (P<0.05) in ischemic cells. Decreases in the mRNA expression levels of Cox6a2 (P<0.001), Gsk3b (P<0.01) and Pik3ca (P<0.001) in the ischemic injury model were also significantly attenuated by SX treatment (P<0.05, P<0.01 and P<0.001, respectively). In addition, the decrease in the protein expression of PI3K (P<0.001) was significantly attenuated by SX treatment (P<0.001). The present findings indicate that SX may protect cardiomyocytes against mitochondrial injury and attenuate alterations in the gene expression of Adcy2, 3 and 8, Cox6a2, Gsk3b and Pik3ca during ischemic injury.

Abstract 2131: Tanshinone IIA can decrease growth factor receptors expression and dural-block both Ras/Raf/MEK/ERK and Ras/PI3K/Akt/mTOR pathways to inhibit human breast cancer BT-20 cells

Abstract Background : Tanshinone IIA (Tan-IIA, C19H18O3) with anti-inflammatory activities and antioxidant properties, is one of the diterpine quinones extracted from Salviae miltiorrhizae radix (Danshen). Tan-IIA can inhibit many human cancer cell lines through different molecular mechanisms. The phosphoinositide-3-kinase (PI3K)/AKT/ mammalian target of rapamycin (mTOR) and RAS/RAF/MEK/ERK pathways are two of the most frequently dysregulated kinase cascades in human cancer. Transmembrane tyrosine kinase has been strongly implicated in the proliferation, survival, and metastasis of human tumors. Both pathways represent important signal transduction mechanisms that facilitate the proliferation and survival of cancers driven by growth factor receptors, such as vascular endothelial growth factor receptor (VEGFR), insulin-like growth factor-I receptor (IGF-IR), or epidermal growth factor receptor (EGFR). Targeting both the Ras/Raf/MEK/ERK and Ras/PI3K/Akt/mTOR Pathways for suppressing inhibitor resistant cells is necessary because the individual downstream components of these signaling cascades either through epigenetic modification or somatic mutation are also known to be frequently altered in cancer, thus contributing to resistance to anticancer therapies and tumorigenesis. Material and methods: In the present study, the human breast cancer BT-20 cells were treated with Tan-IIA in vitro. The cytotoxicity of Tan-IIA was evaluated by MTT assay. The effects of Tan-IIA on the protein expressions of EGFR, IGF-IR, VEGFR, PI3K, AKT, mTOR, Ras, Raf, MEK and ERK and β-actin in the BT-20 cells were examined by western blot analysis. Results: The results showed that Tan-IIA can induce the proliferation inhibition with time and dose dependent and inhibit the activity of the Ras/Raf/MEK/ERK and Ras/PI3K/Akt/mTOR pathways. In addition, it was showed that Tan-IIA treatment inhibited the protein expression levels of EGFR, VEGFR and IGF-IR significantly. Conclusions: These findings indicated that one of the molecular mechanisms for Tan-IIA to inhibit BT-20 cells maybe through inhibiting the protein expression levels of EGFR, VEGFR, IGF-IR and both Ras/Raf/MEK/ERK and Ras/PI3K/Akt/mTOR pathways. The use of Tan-IIA for breast cancer may become a feasible novel therapy option. Further studies are warranted to elucidate its mechanisms fully. Citation Format: Chin Cheng Su. Tanshinone IIA can decrease growth factor receptors expression and dural-block both Ras/Raf/MEK/ERK and Ras/PI3K/Akt/mTOR pathways to inhibit human breast cancer BT-20 cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2131. doi:10.1158/1538-7445.AM2017-2131

The effects and mechanisms of berberine on proliferation of papillary thyroid cancer K1 cells induced by high glucose

Objective: To study the effect and mechanisms of berberine (BBR) on the proliferation of papillary thyroid cancer K1 cells induced by high glucose. Methods: K1 cells were cultured under 5.5 mmol/L or 25 mmol/L glucose condition with or without different concentration of BBR (0, 10, 40 and 80 μmol/L) for 24 hours. The proliferations of K1 cells in each condition were detected by MTT. Western blot was used to measure the expression of nuclear factor erythroid 2-related factor 2(Nrf2), phosphoinositide 3-kinase (PI3K), protein kinase B (Akt) and phosphorylated-Akt (p-Akt). The distribution pattern of Nrf2 in K1 cells was determined using immunofluorescent staining. Results: Compared with 5.5 mmol/L condition, the proliferation rate [(126.64±5.41) % vs (87.31±3.67)%], expression levels of PI3K (0.425±0.019 vs 0.272±0.039), p-Akt/Akt (0.446±0.021 vs 0.168±0.035) and Nrf2 (0.597±0.014 vs 0.308±0.026), and Nrf2 distribution (93.0% vs 23.1%) in nuclear of K 1 cells under 25 mmol/L condition were significantly elevated, respectively (all P<0.01). Addition of BBR in 25 mmol/L condition dose dependently (10, 40, 80 μmol/L) lowered the proliferation rate of K1 cells [(111.76±4.10)%, (70.03±2.18)%, (32.41±3.76)% vs (126.64±5.41)%, all P<0.05], and suppressed the expression of PI3K, p-Akt/Akt, Nrf2, and Nrf2 nuclear distribution (P<0.05). Conclusions: BBR dose dependently inhibited the proliferation of high glucose-induced K1 cells. This effect was associated with the suppression on of PI3K/Akt signaling activation, Nrf2 expression and its nuclear translocation.

Alpha-7 Nicotinic Receptor Signaling Pathway Participates in the Neurogenesis Induced by ChAT-Positive Neurons in the Subventricular Zone.

Choline acetyltransferase-positive (ChAT+) neurons within the subventricular zone (SVZ) have been shown to promote neurogenesis after stroke in mice by secreting acetylcholine (ACh); however, the mechanisms remain unclear. Receptors known to bind ACh include the nicotinic ACh receptors (nAChRs), which are present in the SVZ and have been shown to be important for cell proliferation, differentiation, and survival. In this study, we investigated the neurogenic role of the alpha-7 nAChR (α7 nAChR) in a mouse model of middle cerebral artery occlusion (MCAO) by using α7 nAChR inhibitor methyllycaconitine. Mice subjected to MCAO exhibited elevated expression of cytomembrane and nuclear fibroblast growth factor receptor 1 (FGFR1), as well as increased expression of PI3K, pAkt, doublecortin (DCX), polysialylated - neuronal cell adhesion molecule (PSA-NCAM), and mammalian achaete-scute homolog 1 (Mash1). MCAO mice also had more glial fibrillary acidic protein (GFAP)/5-bromo-2'-deoxyuridine (BrdU)-positive cells and DCX-positive cells in the SVZ than did the sham-operated group. Methyllycaconitine treatment increased cytomembrane FGFR1 expression and GFAP/BrdU-positive cells, upregulated the levels of phosphoinositide 3-kinase (PI3K) and phospho-Akt (pAkt), decreased nuclear FGFR1 expression, decreased the number of DCX-positive cells, and reduced the levels of DCX, PSA-NCAM, and Mash1 in the SVZ of MCAO mice compared with levels in vehicle-treated MCAO mice. MCAO mice treated with α7 nAChR agonist PNU-282987 exhibited the opposite effects. Our data show that α7 nAChR may decrease the proliferation of neural stem cells and promote differentiation of existing neural stem cells after stroke. These results identify a new mechanism of SVZ ChAT+ neuron-induced neurogenesis.

Edoxaban improves venous thrombosis via increasing hydrogen sulfide and homocysteine in rat model.

Anticoagulant therapy is prescribed to millions of patients worldwide for the prevention and treatment of venous thrombosis. Evidence has indicated that edoxaban is a potential drug of oral anticoagulant in the acute treatment of venous thromboembolism. Hydrogen sulfide and homocysteine plasma concentration are indicators of cardiovascular and neurovascular disease risk factors that have attracted considerable attention for regulation of vascular health and homeostasis. However, the molecular mechanism of edoxaban‑mediated differences of hydrogen sulfide and homocysteine has not been investigated in the progression of venous thrombosis. In the present study, the authors analyzed the phosphoinositide 3‑kinase (PI3K)/protein kinase B (AKT) signaling pathway in the vein endothelial cells and expression levels of hydrogen sulfide and homocysteine. Homocysteine‑hydrogen sulfide metabolism through transsulfuration and that transsulfuration capacity and hydrogen sulfide availability have been investigated both invitro and invivo following treatment with edoxaban. Matrix metalloproteinase (MMP) activation and cystathionine β‑synthase (CBS) and cystathionine γ‑lyase (CGL) levels were studied in a cell model and rat model of vein thrombosis prior and post treatment of edoxaban. The therapeutic effects of edoxaban for rats with vein thrombosis were determined by clinical diagnose scores. The results demonstrated that edoxaban increased expression levels of hydrogen sulfide and homocysteine in microvascular endothelial cells. It was observed that the transsulfuration enzymes, CBS and CGL levels were upregulated in murine microvascular endothelial cells. The MMP‑9 expression level and activity and homocysteine‑hydrogen sulfide metabolism were increased in murine microvascular endothelial cells following edoxaban treatment. In addition, CBS and CGL activities were upregulated in murine microvascular endothelial cells and a rat model of venous thrombosis following treatment with edoxaban. Furthermore, it was observed that edoxaban increased PI3K and AKT expression both invitro and invivo. In addition, edoxaban significantly improved endothelial injury and inhibited thrombosis factors expression in rat model of venous thrombosis. In conclusion, these findings suggested that edoxaban can improve venous thrombosis by decreasing hydrogen sulfide and homocysteine through the PI3K/AKT signaling pathway.

Diagnostic Significance of Phosphoinositide 3-Kinase and Mammalian Target of Rapamycin Complex 1 in Preeclampsia.

To examine the association of phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin complex 1 (m-TORC1) with preeclampsia (PE) and to explore their diagnostic significance in PE. A total of 153 singleton pregnant women were enrolled into our study, among which there were 97 patients with PE (mild PE [MPE]: n = 51; severe PE [SPE]: n = 46) and 56 healthy pregnant women (normal controls, NCs). Enzyme-linked immunosorbent assay (ELISA) and Western blot were used in this study. Moreover, a receiver-operating characteristic (ROC) curve was used to estimate the diagnostic significance. After adjustment for confounding factors, at 24 to 28 gestational weeks, the serum levels of PI3K and m-TORC1 were both higher in the MPE and the SPE groups compared to those in the NC group (all P < .001). The serum levels of PI3K were positively correlated with the serum levels of m-TORC1 in both the NC and the PE groups at both 15 to 21 and 24 to 28 gestational weeks (both P < .001). Multivariable linear regression indicated that both PI3K and m-TORC1 were positively correlated with the systolic pressure (both P < .001). At 24 to 28 gestational weeks, there remained relatively high sensitivity and specificity when the serum levels of PI3K and m-TORC1 were used to diagnose PE (both P < .001). A Western blot assay found that there were significant differences in the PI3K and m-TORC1 protein expression among the 3 groups (all P < .001). The serum levels of PI3K and m-TORC1 might have the potential to diagnose PE, while PI3K and m-TORC1 fail to predict PE during early pregnancy.

Fucosterol, isolated from Ecklonia stolonifera, inhibits adipogenesis through modulation of FoxO1 pathway in 3T3-L1 adipocytes.

The purpose of this study was to investigate the effects of fucosterol on adipogenesis of 3T3-L1 preadipocytes and its underlying mechanisms. Fucosterol, isolated from brown algae, Ecklonia stolonifera. We investigated the levels of lipid accumulation using Oil Red O staining. We conducted Western blot analysis to investigate regulatory effects of fucosterol on expression of phosphoinositide 3-kinase (PI3K), Akt, extracellular signal-regulated kinase (ERK), forkhead box protein O 1 (FoxO1) in 3T3-L1 adipocytes. Fucosterol significantly reduced intracellular lipid accumulation of 3T3-L1 adipocytes at concentrations of 25 and 50 μm. Fucosterol downregulated insulin-triggered PI3K/Akt, and ERK pathways. It subsequently decreased expression of adipogenic transcription factors, including PPARγ, C/EBPα and SREBP-1. In addition, fucosterol enhanced SirT1 expression while decreased phospho-FoxO1 expression which resulted in the activation of FoxO1. We revealed that fucosterol inhibited adipogenesis of 3T3-L1 preadipocytes through modulation of FoxO signalling pathway. Therefore, our results suggest that fucosterol may be used for novel agents for the treatment of obesity.

Pre-Clinical Evaluation of the PI3K-p110β/δ Inhibitor KA2237 in Mantle Cell Lymphoma

Background: Mantle cell lymphoma (MCL) accounts for 6% of all non-Hodgkin lymphoma and is a therapeutic challenge. Phosphoinositide-3 kinase (PI3K) has been shown to be an alternative survival pathway in relapsed/refractory MCL. KA2237 (designed by Karus Therapeutics Ltd, Oxfordshire, United Kingdom) is a dual inhibitor of the class I beta and delta isoforms of the 110 kDa catalytic subunit of PI3K. By selectively targeting PI3K-beta and -delta isoforms and preventing their activation, KA2237 may decrease proliferation and induce cell death in susceptible tumor cells.Methods: We assessed the effects of KA2237 on the in vitro cell proliferation of both ibrutinib-sensitive (Mino, Jeko-1, and Rec-1) and primary ibrutinib-resistant (Z-138 and Maver-1) cell lines, and acquired ibrutinib-resistant MCL cell line, Jeko-R. We also tested the viability of patient-derived xenograft (PDX) tumor cells to KA2237. We compared the efficacy of KA2237 with two other commercial PI3K inhibitors, duvelisib (IPI-145, Selleck) and idelalisib (Cal-101, Selleck). Also, we paired these three inhibitors (KA2237, duvelisib and idelalisib) each with ibrutinib to evaluate the potential synergistic effects of these combinations. Lastly, we also tested in vivo efficacy of KA2237 and its combination with ibrutinib in PDX tumor cells.Results: KA2237 inhibited cell proliferation in both ibrutinib-sensitive and ibrutinib-resistant cell lines in a dose-dependent and time-dependent manner. For Mino and Jeko-1, the IC50 was 4.8 uM and 2.9 uM and for Z-138 and Maver-1 cell lines, the IC50 was 0.6 uM and 0.1 uM, respectively. KA2237 also decreased cell viability of ibrutinib-sensitive and ibrutinib-resistant MCL PDX tumor cells. However, KA2237 did not decrease the cell viability of normal human peripheral blood mono-nuclear cells. KA2237 arrested phase G0/G1 in Rec-1 and Jeko-R cell lines. We detected the expression of PI3K isoforms in MCL, finding higher expression of PI3K β and δ in MCL-resistant cell lines as compared with sensitive cell lines. We found that KA2237 induced MCL cell apoptosis in a time-dependent and dose-dependent manner. In comparison with duvelisib and idelalisib, KA2237 achieved greater inhibition of cell viability, cell apoptosis and cell cycle arrest. Furthermore, we found synergistic effects of KA2237 and ibrutinib combination in several MCL cell lines and in PDX models. In an ibrutinib-resistant PDX model, KA2237 treated mice reduced tumor burden significantly compared with vehicle control, and higher tumor growth inhibition was achieved as compared with ibrutinib.Conclusion: The novel PI3K inhibitor, KA2237 may be a potential candidate for MCL therapy, especially in the ibrutinib-resistant cases. DisclosuresWang:Acerta Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno Therapeutics: Research Funding; Pharmacyclics: Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx: Research Funding; BeiGene: Research Funding; Asana BioSciences: Research Funding; Kite Pharma: Research Funding; Celgene: Research Funding.

RNA transcript expression of IGF-I/PI3K pathway components in regenerating skeletal muscle is sensitive to initial injury intensity

ObjectiveSkeletal muscle regeneration is a complex process involving the coordinated input from multiple stimuli. Of these processes, actions of the insulin-like growth factor-I (IGF-I) and phosphoinositide 3-kinase (PI3K) pathways are vital; however, whether IGF-I or PI3K expression is modified during regeneration relative to initial damage intensity is unknown. The objective of this study was to determine whether mRNA expression of IGF-I/PI3K pathway components was differentially regulated during muscle regeneration in mice in response to traumatic injury induced by freezing of two different durations. DesignTraumatic injury was imposed by applying a 6-mm diameter cylindrical steel probe, cooled to the temperature of dry ice (−79°C), to the belly of the left tibialis anterior muscle of 12-week-old C57BL/6J mice for either 5s (5s) or 10s (10s). The right leg served as the uninjured control. RNA was obtained from injured and control muscles following 3, 7, and 21days recovery and examined by real-time PCR. Expression of transcripts within the IGF, PI3K, and Akt families, as well as for myogenic regulatory factors and micro-RNAs were studied. ResultsThree days following injury, there was significantly increased expression of Igf1, Igf2, Igf1r, Igf2r, Pik3cb, Pik3cd, Pik3cg, Pik3r1, Pik3r5, Akt1, and Akt3 in response to either 5s or 10s injury compared to uninjured control muscle. There was a significantly greater expression of Pik3cb, Pik3cd, Pik3cg, Pik3r5, Akt1, and Akt3 in 10s injured muscle compared to 5s injured muscle. Seven days following injury, we observed significantly increased expression of Igf1, Igf2, Pik3cd, and Pik3cg in injured muscle compared to control muscle in response to 10s freeze injury. We also observed significantly reduced expression of Igf1r and miR-133a in response to 5s freeze injury compared to control muscle, and significantly reduced expression of Ckm, miR-1 and miR-133a in response to 10s freeze injury as compared to control. Twenty-one days following injury, 5s freeze-injured muscle exhibited significantly increased expression of Igf2, Igf2r, Pik3cg, Akt3, Myod1, Myog, Myf5, and miR-206 compared to control muscle, while 10s freeze-injured muscles showed significantly increased expression of Igf2, Igf2r, Pik3cb, Pik3cd, Pik3r5, Akt1, Akt3, and Myog compared to control. Expression of miR-1 was significantly reduced in 10s freeze-injured muscle compared to control muscle at this time. There were no significant differences in RNA expression between 5s and 10s injury at either 7d or 21d recovery in any transcript examined. ConclusionsDuring early skeletal muscle regeneration in mice, transcript expressions for some components of the IGF-I/PI3K pathway are sensitive to initial injury intensity induced by freeze damage.

Structural basis for decreased induction of class IB PI3-kinases expression by MIF inhibitors.

Macrophage migration inhibitory factor (MIF) is a master regulator of proinflammatory cytokines and plays pathological roles when not properly regulated in rheumatoid arthritis, lupus, atherosclerosis, asthma and cancer. Unlike canonical cytokines, MIF has vestigial keto‐enol tautomerase activity. Most of the current MIF inhibitors were screened for the inhibition of this enzymatic activity. However, only some of the enzymatic inhibitors inhibit receptor‐mediated biological functions of MIF, such as cell recruitment, through an unknown molecular mechanism. The goal of this study was to understand the molecular basis underlying the pharmacological inhibition of biological functions of MIF. Here, we demonstrate how the structural changes caused upon inhibitor binding translate into the alteration of MIF‐induced downstream signalling. Macrophage migration inhibitory factor activates phosphoinositide 3‐kinases (PI3Ks) that play a pivotal role in immune cell recruitment in health and disease. There are several different PI3K isoforms, but little is known about how they respond to MIF. We demonstrate that MIF up‐regulates the expression of Class IB PI3Ks in leucocytes. We also demonstrate that MIF tautomerase active site inhibitors down‐regulate the expression of Class IB PI3Ks as well as leucocyte recruitment in vitro and in vivo. Finally, based on our MIF:inhibitor complex crystal structures, we hypothesize that the reduction in Class IB PI3K expression occurs because of the displacement of Pro1 towards the second loop of MIF upon inhibitor binding, which results in increased flexibility of the loop 2 and sub‐optimal MIF binding to its receptors. These results will provide molecular insights for fine‐tuning the biological functions of MIF.

Abstract 2185: Sann-Joong-Kuey-Jian-Tang can inhibit human breast cancer cells through dural- blocking both the Ras/Raf/MEK/ERK and Ras/PI3K/Akt/mTOR pathways

Abstract Sann-Joong-Kuey-Jian-Tang (SJKJT) consists of 17 species of medicinal herbs, is a traditional Chinese medicine prescription, and has been used as complementary medication for a number of types of solid cancer in Taiwan. Transmembrane tyrosine kinase has been strongly implicated in the growth, survival, and metastasis of a wide variety of human tumors. The phosphoinositide-3-kinase (PI3K)/AKT/ mammalian target of rapamycin (mTOR) and RAS/RAF/MEK/ERK pathways are two of the most frequently dysregulated kinase cascades in human cancer were well documented. Both pathways represent important signal transduction mechanisms that facilitate the proliferation and survival of cancers driven by growth factor receptors, such as vascular endothelial growth factor receptor (VEGFR), insulin-like growth factor-I receptor (IGF-IR), human epidermal growth factor receptor 2 (HER2) or epidermal growth factor receptor (EGFR).The individual downstream components of these signaling cascades either through somatic mutation or epigenetic modification, are also known to be frequently altered in cancer, thus contributing to tumorigenesis and resistance to anticancer therapies. Targeting both the Ras/Raf/MEK/ERK and Ras/PI3K/Akt/mTOR Pathways for suppressing Inhibitor Resistant Cells is necessary. In the present study, the human breast cancer BT-20 and MCF-7 cells were treated with SJKJT in vitro. The cytotoxicity of SJKJT were evaluated by 3–(4,5–dimethylthiazol–2–y1)–2,5–diphenyltetrazolium bromide (MTT) assay. The effects of SJKJT on the protein expressions of VEGFR, IGF-IR, PI3K, AKT, mTOR, Ras, Raf, MEK and ERK and β-actin in the BT-20 and MCF-7 cells were examined by western blot analysis. The results showed that SJKJT can induce the proliferation inhibition with time and dose dependent. As a potential mechanism, it was noted that SJKJT treatment significantly inhibited the activity of the Ras/Raf/MEK/ERK and Ras/PI3K/Akt/mTOR pathways, which played a protective role against the cytotoxicity. In addition, it was demonstrated that SJKJT treatment inhibited the protein expressions of VEGFR, EGFR and IGF-IR significantly. These results suggest that one of the molecular mechanisms for SJKJT to inhibit breast cancer BT-20 and MCF-7 cells maybe through inhibiting the protein expressions of VEGFR, EGFR, IGF-IR and both Ras/Raf/MEK/ERK and Ras/PI3K/Akt/mTOR pathways. The use of traditional chinese medicine prescription SJKJT may become a feasible novel therapy option. Further studies are warranted to fully elucidate its mechanisms of action. Citation Format: CHIN CHENG SU. Sann-Joong-Kuey-Jian-Tang can inhibit human breast cancer cells through dural- blocking both the Ras/Raf/MEK/ERK and Ras/PI3K/Akt/mTOR pathways. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2185.

Effect of moxa-burning heat stimulating Liangmen (ST 21) and Zusanli (ST 36) on proliferation and apoptosis signaling proteins in rats with stress-induced gastric ulcer

ObjectiveTo observe the effect of moxa-burning heat stimulating acupoints of Liangmen (ST 21) and Zusanli (ST 36) on the proliferation and apoptosis signaling proteins in rats with stress-induced gastric ulcer. MethodsForty rats were randomly divided into four groups: negative control (NC), ulcer control (UC), acupoints of stomach meridian (ASM), and acupoints control (AC). The acute gastric ulcer model was established by bound and water immersion. Rats in NC and UC groups didn't receive any moxa-burning heat stimulating treatment, while rats in ASM and AC groups were treated with buringmoxa heat stimulating the acupoints of Liangmen (ST 21) and Zusanli (ST 36) and their controlled points, respectively. Rats in all groups were sacrificed after 12 consecutive days treatment. The ulcer index was evaluated by using Guth's method. The expression of tumor necrosis factor-alpha (TNF-α), apoptotic protease activating facter-1 (Apaf-1), Caspase-3, p21 activated kinase 1 (PAK1), extracellular regulated protein kinases 2 (ERK2), phosphorylated ERK2 (pERK2), phosphoinositide 3-kinase (PI3K) and RAC-alpha serine/threonine-protein kinase (Akt) in gastric mucosa was detected by enzyme linked immunosorbent assay (ELISA). ResultsCompared with UC group, the ulcer index of ASM and AC groups decreased, and the injured gastric mucosa was improved, the expression of TNF-α, Apaf-1 and Caspase-3 in gastric mucosa was significantly reduced (P < 0.05), while the expression of PAK1, ERK2, pERK2, PI3K and Akt in gastric mucosa was significantly increased (P < 0.05). And ASM showed better effect than AC group (P < 0.05). ConclusionMoxa-burning Heat stimulating of Liangmen (ST 21) and Zusanli (ST 36) could promote the recovery of gastric mucosal lesion probably by inhibiting cell apoptosis and promoting cell proliferation in stress-induced gastric ulcer.

Silybin suppresses cell proliferation and induces apoptosis of multiple myeloma cells via the PI3K/Akt/mTOR signaling pathway

Silybin is a biologically active component extracted from the seeds of Silybum marianum, which has been shown to have inhibitory effects on prostate, skin, bladder, lung and colon cancer cells, in addition to its efficacy in the treatment of liver diseases, including hepatitis and cirrhosis. The aim of the present study was to investigate whether silybin suppresses the proliferation and induces apoptosis of multiple myeloma (MM) cells and to elucidate its molecular targets. The proliferative and apoptotic rates of the U266 MM cell line were assessed using MTT and flow‑cytometric assays, respectively. Western blot analysis was used to assess the protein levels of phosphoinositide‑3 kinase (PI3K), phosphorylated (p)‑Akt and p‑mammalian target of rapamycin (mTOR) in U266 cells. In addition, PI3K inhibitor LY294002 or activator insulin‑like growth factor 1 were used to investigate the involvement of the PI3K/Akt‑mTOR signaling pathway in the effect of silybin on U266 cells. The results revealed that silybin restrained the proliferation and enhanced the apoptosis of U266 cells. Furthermore, silybin inhibited the protein expression of PI3K, p‑Akt and p‑mTOR in U266 cells. Of note, inhibition of PI3K facilitated silybin‑mediated reduction of mTOR activation, cell proliferation and induction of apoptosis in U266 cells, while activation of PI3K attenuated the effects of silybin. In conclusion, silybin suppressed cell proliferation and promoted apoptosis of U266 cells via PI3K/Akt-mTOR signaling pathways.

Role of the PTEN/PI3K/VEGF pathway in the development of Kawasaki disease.

Kawasaki disease (KD) is a disease of unknown etiology and the leading cause of childhood acquired heart disease. In this study, the significance of the phosphatase and tensin homolog (PTEN)/phosphoinositide 3-kinase (PI3K)/vascular endothelial growth factor (VEGF) pathway in the development of KD was investigated in a rabbit model. Rabbits were divided into the control group, which received saline injection, and the experimental group, which was treated with bovine serum albumin to induce arthritis and KD. After 1, 7 and 30 days the animals were sacrificed, and the white blood cell count, serum VEGF, and serum creatine kinase (CK) levels were measured. The coronary artery was examined histologically as well as immunohistochemically for PTEN and PI3K. After the induction of arthritis, coronary artery of the rabbits showed endothelial cell swelling, osteoporosis, necrosis and inflammatory cell infiltration. PTEN expression in these rabbits increased with the increasing number of modeling days. The expression of PI3K showed a decreasing trend. The number of white blood cells in rabbits after KD modeling were significantly higher than those in the controls. One day and 7 days after modeling the serum VEGF level in KD rabbits was significantly higher than that in the control group after 1 and 7 days followed by a decrease by 30 days. There was no significant change in serum CK on the day after the modeling, and the serum CK level was significantly higher after 7 and 30 days. In conclusion, the expression of PTEN/PI3K was altered at different stages of KD. PTEN expression gradually increased with the disease progression, while the expression of PI3K gradually decreased. Serum markers indicated that the PTEN/PI3K/VEGF signaling pathway is important in the vascular injury in KD.

Upregulation of microRNA-31 targeting integrin α5 suppresses tumor cell invasion and metastasis by indirectly regulating PI3K/AKT pathway in human gastric cancer SGC7901 cells.

To verify the hypothesis that upregulation of microRNA-31 (miR-31) targeting integrin α5 (ITGA5) suppresses tumor cell invasion and metastasis by indirectly regulating phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway in human SGC7901 gastric cancer (GC) cells. The miRTarBase was used to predict whether ITGA5 is the target gene of miR-31, which was further confirmed by luciferase reporter gene assay. The SGC7901 GC cells were divided into five groups including the blank, miR-31 mimic, miR-31 mimic control, miR-31 inhibitor, and miR-31 inhibitor control groups. Reverse transcriptase-polymerase chain reaction (RT-PCR), western blotting, cell scratch test, and transwell assays were respectively performed in our study. TGA5 was found as the target gene of miR-31. The RT-PCR detection revealed that, compared with the blank group, ITGA5 messenger RNA (mRNA) expression decreased in the miR-31 mimic group, but increased in the miR-31 inhibitor group. The western blotting examination suggested that the expressions of ITGA5, PI3K, and AKT proteins reduced in the miR-31 mimic group, but enhanced in the miR-31 inhibitor group when compared to the blank group, respectively. The cell scratch and transwell assays indicated that the miR-31 expressions were negatively associated with GC cell migration and invasion. Besides, RT-PCR combined with western blotting demonstrated that the miR-31 expressions were higher in the normal tissues than those in the GC tissues, while the ITGA5 mRNA and protein showed lower expression in the normal tissues than they did in the GC tissues. Our study concluded that upregulation of miR-31 targeting ITGA5 may suppress tumor cell invasion and metastasis by indirectly regulating PI3K/AKT signaling pathway in human SGC7901 GC cells.