Osteopontin promotes gastric cancer progression via phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin signaling pathway

BACKGROUND Gastric cancer(GC)is one of the most common malignant tumors.Osteopontin(OPN)is thought to be closely related to the occurrence,metastasis and prognosis of many types of tumors.AIM To investigate the effects of OPN on the proliferation,invasion and migration of GC cells and its possible mechanism.METHODS The mRNA and protein expression of OPN in the GC cells were analyzed by realtime quantitative-reverse transcription polymerase chain reaction and western blotting,and observe the effect of varying degree expression OPN on the proliferation and other behaviors of GC.Next,the effects of OPN knockdown on GC cells migration and invasion were examined.The short hairpin RNA(shRNA)and negative control shRNA targeting OPN-shRNA were transfected into the cells according to the manufacturer’s instructions.Non transfected cells were classified as control in the identical transfecting process.24 h after RNA transfection cell proliferation activity was detected by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-diphenytetrazoliumromide assay,and cell invasiveness and migration were detected by Trans well assay.Meanwhile,the expression of protein kinase B(AKT),matrix metalloproteinase 2(MMP-2)and vascular endothelial growth factor(VEGF)in the human GC cell lines was detected by reverse transcription polymerase chain reaction and western blotting.RESULTS The results of this study revealed that OPN mRNA and protein expression levels were highly expressed in SGC-7901 cells.OPN knockdown by specific shRNA noticeably reduced the capabilities of proliferation,invasion and migration of SGC-7901 cells.Moreover,in the experiments of investigating the underlying mechanism,results showed that OPN knockdown could down-regulated the expression of MMP-2 and VEGF,it also decreased the phosphorylation of AKT.Meanwhile,the protein expression levels of MMP-2,VEGF and phosphorylated AKT was noticeable lower than that in control group in the GC cells after they were added to phosphatidylinositol-3-kinase(PI3K)inhibitor(LY294002).CONCLUSION These results suggested that OPN though PI3K/AKT/mammalian target of rapamycin signal pathway to upregulate MMP-2 and VEGF expression,which contribute SGC-7901 cells to proliferation,invasion and migration.Thus,our results demonstrate that OPN may serve as a novel prognostic biomarkers as well as a potential therapeutic targets for GC.

Roles of phosphatidylinositol-3-kinases signaling pathway in inflammation-related cancer:Impact of rs10889677 variant and buparlisib in colitis-associated cancer

BACKGROUND Phosphatidylinositol-3-kinases(PI3K)is a well-known route in inflammationrelated cancer.Recent discovery on PI3K-related genes revealed a potential variant that links ulcerative colitis(UC)and colorectal cancer(CRC)with colitisassociated cancer(CAC).PI3K/AKT pathway has been recommended as a potential additional therapeutic option for CRC due to its substantial role in modifying cellular processes.Buparlisib is a pan-class I PI3K inhibitor previously shown to reduce tumor growth.AIM To investigate the regulation of rs10889677 and the role of buparlisib in the PI3K signaling pathway in CAC pathogenesis.METHODS Genomic DNA from 32 colonic samples,including CAC(n=7),UC(n=10)and CRC(n=15),was sequenced for the rs10889677 mutation.The mutant and wildtype fragments were amplified and cloned in the pmirGLO vector.The luciferase activity of cloned vectors was assessed after transfection into the HT29 cell line.CAC mice were induced by a mixture of a single azoxymethane injection and three cycles of dextran sulphate sodium,then buparlisib was administered after 14 d.The excised colon was subjected to immunohistochemistry for Ki67 and Cleaved-caspase-3 markers and quantitative real-time polymerase chain reaction analysis for Pdk1 and Sgk2.RESULTS Luciferase activity decreased by 2.07-fold in the rs10889677 mutant,confirming the hypothesis that the variant disrupted miRNA binding sites,which led to an increase in IL23R expression and the activation of the PI3K signaling pathway.Furthermore,CAC-induced mice had a significantly higher disease activity index(P<0.05).Buparlisib treatment significantly decreased mean weight loss in CAC-induced mice(P<0.05),reduced the percentage of proliferating cells by 5%,and increased the number of apoptotic cells.The treatment also caused a downward trend of Pdk1 expression and significantly decreased Sgk2 expression.CONCLUSION Our findings suggested that the rs10889677 variant as a critical initiator of the PI3K signaling pathway,and buparlisib had the ability to prevent PI3K-non-AKT activation in the pathophysiology of CAC.

Cytotoxicity of nonylphenol on spermatogonial stem cells via phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin pathway

BACKGROUND With continuous advancement of industrial society,environmental pollution has become more and more serious.There has been an increase in infertility caused by environmental factors.Nonylphenol(NP)is a stable degradation product widely used in daily life and production and has been proven to affect male fertility.However,the underlying mechanisms therein are unclear.Thus,it is necessary to study the effect and mechanism of NP on spermatogonial stem cells(SSCs).AIM To investigate the cytotoxic effect of NP on SSCs via the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin(PI3K/AKT/mTOR)pathway.METHODS SSCs were treated with NP at 0,10,20 or 30μmol.MTT assay was performed to evaluate the effect of NP on the proliferation of SSCs.Flow cytometry was conducted to measure SSC apoptosis.The expression of Bad,Bcl-2,cytochrome-c,pro-Caspase 9,SOX-2,OCT-4,Nanog,Nanos3,Stra8,Scp3,GFRα1,CD90,VASA,Nanos2,KIT,PLZF and PI3K/AKT/mTOR-related proteins was observed by western blot,and the mRNA expression of SOX-2,OCT-4 and Nanog was detected by quantitative reverse transcription polymerase chain reaction.RESULTS Compared with untreated cells(0μmol NP),SSCs treated with NP at all concentrations showed a decrease in cell proliferation and expression of Bcl-2,Nanog,OCT-4,SOX-2,Nanos3,Stra8,Scp3,GFRα1,CD90,VASA,Nanos2,KIT,and PLZF(P<0.05),whereas the expression of Bad,cytochrome-c,and pro-Caspase 9 increased significantly(P<0.05).We further examined the PI3K/AKT/mTOR pathway and found that the phosphorylation of PI3K,AKT,mTORC1,and S6K was significantly decreased by NP at all concentrations compared to that in untreated SSCs(P<0.05).NP exerted the greatest effect at 30μmol among all NP concentrations.CONCLUSION NP attenuated the proliferation,differentiation and stemness maintenance of SSCs while promoting apoptosis and oxidative stress.The associated mechanism may be related to the PI3K/AKT/mTOR pathway.

Telencephalin protects PAJU cells from amyloid beta protein-induced apoptosis by activating the ezrin/radixin/moesin protein family/phosphatidylinositol-3-kinase/protein kinase B pathway

Telencephalin is a neural glycoprotein that reduces apoptosis induced by amyloid beta protein in the human neural tumor cell line PAJU. In this study, we examined the role of the ezrin/radixin/moesin protein family/phosphatidylinositol-3-kinase/protein kinase B pathway in this process. Western blot analysis demonstrated that telencephalin, phosphorylated ezrin/radixin/moesin and phosphatidylinositol-3-kinase/protein kinase B were not expressed in PAJU cells transfected with empty plasmid, while they were expressed in PAJU cells transfected with a telencephalin expression plasmid. After treatment with 1.0 nM amyloid beta protein 42, expression of telencephalin and phosphorylated phosphatidylinositol-3-kinase/protein kinase B in the transfected cells gradually diminished, while levels of phosphorylated ezrin/radixin/moesin increased. In addition, the high levels of telencephalin, phosphorylated ezrin/radixin/moesin and phosphatidylinositol-3-kinase/protein kinase B expression in PAJU cells transfected with a telencephalin expression plasmid could be suppressed by the phosphatidylinositol-3-kinase inhibitor LY294002. These findings indicate that telencephalin activates the ezrin/radixin/moesin family/phosphatidylinositol-3-kinase/protein kinase B pathway and protects PAJU cells from amyloid beta protein-induced apoptosis.

Tumor-related factor complement Clq/TNF-related protein 6 affects the development of digestive system tumors through the phosphatidylinositol 3-kinase pathway

In this editorial,we review the work of Razali et al published in World J Gas-troenterology,with a particular focus on the effect of rs10889677 variation in the phosphatidylinositol 3-kinase(PI3K)pathway and buparlisib on colitis-associated cancer.The role of PI3K in promoting cancer progression has been widely recognized,as it is involved in regulating the survival,differentiation,and prolif-eration of cancer cells.The complement Clq/TNF-related protein 6(CTRP6)is a newer tumor-associated factor.Recent studies have revealed the pro-tumor effect of CTRP6 in gastric cancer,hepatocellular carcinoma,colorectal cancer,and other gastrointestinal tumors through the PI3K pathway.This article attempts to reveal the mechanism through which the CTRP6 affects the development of digestive system tumors through the PI3K pathway by summarizing recent research.

Bornyl acetate extracted from Sharen(Fructus Amomi)inhibits proliferation,invasion and induces apoptosis by suppressing phosphatidylinositol-3-kinase/protein kinase B signaling in colorectal cancer

OBJECTIVE:To investigate the antitumor effects of bornyl acetate(BA)isolated from Sharen(Fructus Amomi)in colorectal cancer(CRC)and the underlying mechanisms.METHODS:SW480 and HT29 cells were treated with increasing doses of BA in order to determine its antitumor effects in vitro.Cell viability,colony formation,cell cycle,and apoptosis as well as migration and invasion were assessed using various assays.In addition,the in vivo antitumor effects of BA were assessed using a xenograft mouse model.We then assessed the mechanism of action of BA by conducting pathway activator-mediated rescue experiments and assessed the protein levels by Western blot analysis.RESULTS:BA showed anti-CRC tumor activities in vitro by suppressing cell proliferation and colony formation,inducing apoptosis,blocking cell cycle,and inhibiting migration and invasion.These effects were mediated via suppression of the phosphatidylinositol-3-kinase/protein kinase B(PI3K/AKT)pathway.In the tumor xenograft experiment,BA was found to repress tumor growth in vivo with low toxicity.CONCLUSIONS:The results demonstrated that BA exerts antitumor effects by suppressing the PI3K/AKT pathway,with low toxicity.Thus,BA might be a potential novel therapeutic agent for CRC.

Influence of Phosphatidylinositol-3-Kinase/Protein Kinase B-Mammalian Target of Rapamycin Signaling Pathway on the Neuropathic Pain Complicated by Nucleoside Reverse Transcriptase Inhibitors for the Treatment of HIV Infection

Background： Nucleoside reverse transcriptase inhibitors （NRTIs） are the earliest and most commonly used anti-human immunodeficiency virus drugs and play an important role in high active antiretroviral therapy. However, NRTI drug therapy can cause peripheral neuropathic pain. In this study, we aimed to investigate the mechanisms ofrapamycin on the pain sensitization of model mice by in vivo experiments to explore the effect of mammalian target of rapamycin （mTOR） in the pathogenesis ofneuropathic pain caused by NRTIs. Methods： Male Kun Ming （KM） mice weighing 20-2 g were divided into control, 2 mg/kg rapamycin, 12 mg/kg stavudine, and CMC-Na groups. Drugs were orally administered to mice for 42 consecutive days. The von Frey filament detection and thermal pain tests were conducted on day 7, 14, 21, 28, 35, and 42 after drug administration. After the last behavioral tests, immunohistochemistry and western blotting assay were used for the measurement of mTOR and other biomarkers. Multivariate analysis of variance was used. Results： The beneficial effects ofrapamycin on neuropathic pain were attributed to a reduction in mammalian target of rapamycin sensitive complex 1 （mTORC1）-positive cells （70.80± 2.41 vs. 112.30 ± 5.66, F = 34.36, P 〈 0.01 ） and mTORC1 activity in the mouse spinal cord. Mechanistic studies revealed that Protein Kinase B （Akt）/mTOR signaling pathway blockade with rapamycin prevented the phosphorylation of mTORC1 in stavudine-intoxicated mice （0.72 ± 0.04 vs. 0.86 ± 0.03, F=4.24, P = 0.045）, as well as decreased the expression of phospho-pTOS6K （0.47 ± 0.01 vs. 0.68 ± 0.03, F=6.01, P = 0.022） and phospho-4EBP1 （0.90 ± 0.04 vs. 0.94 ± 0.06, F= 0.28, P = 0.646）. Conclusions： Taken together, these results suggest that stavudine elevates the expression and activity of mTORC1 in the spinal cord through activating the Akt/mTOR signaling pathway. The data also provide evidence that rapamycin might be useful for the treatment of peripheral neuropathic pain.

Quercetin-3-O-β-D-glucuronide Inhibits Mitochondria Pathway-mediated Platelet Apoptosis via the Phosphatidylinositol-3-kinase/AKT Pathway in Immunological Bone Marrow Failure

Objective: Quercetin-3-O-β-D-glucuronide(QG) can alleviate immunological bone marrow failure(BMF) by increasing platelet counts. However, the principal mechanism is less known. This study aimed at deciphering the possible underlying mechanism of QG that is indicated in thrombocytopenic purpura. Methods: In vitro and in vivo experiments were carried out for investigating the mechanism behind QG-facilitated inhibition of mitochondrial pathway-mediated excessive apoptosis of platelets through the phosphatidylinositol-3-kinase(PI3K)/AKT pathway. Results: Our results revealed that QG, the main effective ingredient of Herba Sarcandrae, increases the number of platelets and decreases the expression of Bax, Bad, Bid, and caspase-9 in immunological BMF, indicating the inhibition of mitochondrial pathway-mediated apoptosis. Moreover, we found that the protein and m RNA expressions, as well as the phosphorylated levels of PI3K and AKT, were increased significantly by QG, suggesting the activation of the PI3K/AKT pathway. Furthermore, the inhibition of the PI3K/AKT pathway by LY294002 antagonizes the effects of QG on platelet counts and mitochondrial pathway-mediated apoptosis. Conclusion: We demonstrate that QG inhibits the mitochondria pathway-mediated platelet apoptosis via the PI3K/AKT pathway in immunological BMF. This study thus sheds light on exploring the possible regulatory mechanism of traditional Chinese medicine in the treatment of thrombocytopenia induced by BMF.

Response of Subcutaneous Xenografts of Endometrial Cancer in Nude Mice to Inhibitors of Phosphatidylinositol 3-Kinase/Akt and Mitogen-Activated Protein Kinase (MAPK) Pathways: An Effective Therapeutic Strategy for Endometrial Cancer

Objective: This study was designed to explore whether inhibition of the extracellular-regulated kinase (ERK) and phosphatidylinositol-3-kinase (PI3K) signaling pathways can inhibit the growth of xenografts of endometrial cancer cell lines with different estrogen receptors (ER) profiles in vivo and to provide preliminary laboratory basis for the probability of endometrial adenocarcinoma treatment with blockage of the two pathways, especially to endometrial cancer with low ER status. Methods: Human endometrial cancer Ishikawa bearing ER and HEC-1Awith low ER status cells were subcutaneously injected into BALB/c nude mice to establish endometrial cancer xenograft tumor models. The effects of PI3K/Akt inhibitor LY294002, MAPK/ERK1/2 inhibitor PD-98059 and their combinations on the growth of the xenograft tumors and apoptotic state of Ishikawa and HEC-1Acells were tested in vivo using the inhibitory rate, the terminal deoxynucleotidyl transferase-mediated nick-end labeling assay, H/E-stain. Western blot analysis was used to detect the alterations of activated ERK (P-ERK) and AKT (P-AKT) during this process. Results: LY294002, a PI3K/Akt pathway inhibitor, induced significant suppression in the growth of both Ishikawa and HEC-1Acell xenograft tumors, concomitant with increased apoptosis in xenografts as evidenced by TUNEL. A similar effect was also observed when the MAPK/ERK1/2 signaling pathway was inhibited by PD98059. Concurrent inhibition of the PI3K/Akt and MAPK/ERK1/2 pathways showed enhanced anti-tumor effects in vivo as indicated by increased apoptosis. At the same time, the levels of P-ERK and P-AKT in both xenograft tumors decreased, and their levels in combination group was the lowest. Conclusions: PD98059, LY294002 and their combinations showed remarkable inhibitory effects on xenograft tumors of endometrial carcinoma cell lines with different expression status of ER in vivo through blockage of PI3K/Akt and MAPK/ERK1/2 signaling pathways. This suggests that targeting these pathways may be an effective therapeutic strategy against endometrial carcinomas, especially for ER-negative cancers which show poor response to endocrinal therapy.

Phosphatidylinositol 3-kinase/Akt pathway regulates hepatic stellate cell apoptosis

AIM: To investigate the role of phosphatidylinositol 3-kinase (PI 3-K)/Akt signaling pathway in the balance of HSC activation and apoptosis in rat hepatic stellate cells (HSC). METHODS: An activated HSC cell line was used in this study. LY 294002, the PI 3-K/Akt signal pathway block-er was used to investigate the molecular events on apoptosis in HSC and to interpret the role of this path-way in HSC apoptosis. Immunocytochemistry, Western blot and reverse transcription polymerase chain reac-tion (RT-PCR) analysis were applied to detect the ex-pression of PI 3-K, and simultaneously phosphorylated-Akt (p-Akt) and total-Akt were determined by Western blot. The HSC apoptosis was examined by annexin-V/ propidium iodide double-labelled flow cytometry and transmission electron microscopy. RESULTS: The apoptosis rates in LY 294002 (30.82% ± 2.90%) and LY 294002 + PDGF-BB (28.16% ± 2.58%) groups were signif icantly increased compared with those of control (9.02% ± 1.81%) and PDGF-BB (4.35% ± 1.18%). PDGF-BB augmented PI 3-K and p-Akt expres-sion. LY 294002 signif icantly reduced the contents of PI 3-K and p-Akt. mRNA transcription evaluated by RT-PCR showed similar tendencies as protein expression. CONCLUSION: Inhibition of PI 3-K/Akt signaling path-way induces apoptosis in HSC.

Role of phosphoinositide 3-kinase in the pathogenesis of acute pancreatitis

A large body of experimental and clinical data supports the notion that inflammation in acute pancreatitis has a crucial role in the pathogenesis of local and systemic damage and is a major determinant of clinical severity. Thus, research has recently focused on molecules that can regulate the inflammatory processes, such as phosphoinositide 3-kinases (PI3Ks), a family of lipid and protein kinases involved in intracellular signal transduction. Studies using genetic ablation or pharmacologic inhibitors of different PI3K isoforms, in particular the class I PI3K&#x003b4; and PI3K&#x003b3;, have contributed to a greater understanding of the roles of these kinases in the modulation of inflammatory and immune responses. Recent data suggest that PI3Ks are also involved in the pathogenesis of acute pancreatitis. Activation of the PI3K signaling pathway, and in particular of the class IB PI3K&#x003b3; isoform, has a significant role in those events which are necessary for the initiation of acute pancreatic injury, namely calcium signaling alteration, trypsinogen activation, and nuclear factor-&#x003ba;B transcription. Moreover, PI3K&#x003b3; is instrumental in modulating acinar cell apoptosis, and regulating local neutrophil infiltration and systemic inflammatory responses during the course of experimental acute pancreatitis. The availability of PI3K inhibitors selective for specific isoforms may provide new valuable therapeutic strategies to improve the clinical course of this disease. This article presents a brief summary of PI3K structure and function, and highlights recent advances that implicate PI3Ks in the pathogenesis of acute pancreatitis.

Alterations in the human epidermal growth factor receptor 2-phosphatidylinositol 3-kinase-v-Akt pathway in gastric cancer

AIM:To investigate human epidermal growth factor receptor 2(HER2)-phosphatidylinositol 3-kinase(PI3K)-vAkt murine thymoma viral oncogene homolog signaling pathway.METHODS:We analyzed 231 formalin-fixed,paraffinembedded gastric cancer tissue specimens from Japanese patients who had undergone surgical treatment.The patients' age,sex,tumor location,depth of invasion,pathological type,lymph node metastasis,and pathological stage were determined by a review of the medical records.Expression of HER2 was analyzed by immunohistochemistry(IHC) using the HercepTest TM kit.Standard criteria for HER2 positivity(0,1+,2+,and 3+) were used.Tumors that scored 3+ were considered HER2-positive.Expression of phospho Akt(pAkt) was also analyzed by IHC.Tumors were considered pAkt-positive when the percentage of positive tumor cells was 10% or more.PI3K,catalytic,alpha polypeptide(PIK3CA) mutations in exons 1,9 and 20 were analyzed by pyrosequencing.Epstein-Barr virus(EBV) infection was analyzed by in situ hybridization targeting EBV-encoded small RNA(EBER) with an EBER-RNA probe.Microsatellite instability(MSI) was analyzed by polymerase chain reaction using the mononucleotide markers BAT25 and BAT26.RESULTS:HER2 expression levels of 0,1+,2+ and 3+ were found in 167(72%),32(14%),12(5%) and 20(8.7%) samples,respectively.HER2 overexpression(IHC 3+) significantly correlated with intestinal histological type(15/20 vs 98 /205,P = 0.05).PIK3CA mutations were present in 20 cases(8.7%) and significantly correlated with MSI(10/20 vs 9/211,P < 0.01).The mutation frequency was high(21%) in T4 cancers and very low(6%) in T2 cancers.Mutations in exons 1,9 and 20 were detected in 5(2%),9(4%) and 7(3%) cases,respectively.Two new types of PIK3CA mutation,R88Q and R108H,were found in exon1.All PIK3CA mutations were heterozygous missense singlebase substitutions,the most common being H1047R(6/20,30%) in exon20.Eighteen cancers(8%) were EBV-positive and this positivity significantly correlated with a diffuse histological type(13/18 vs 93/198,P = 0.04).There were 7 cases of lymphoepithelioma-like carcinomas(LELC) and 6 of those cases were EBV-positive(percent/EBV:6/18,33%;percent/all LELC:6/7,86%).pAkt expression was positive in 119(53%) cases but showed no correlation with clinicopathological characteristics.pAkt expression was significantly correlated with HER2 overexpression(16/20 vs 103/211,P < 0.01) but not with PIK3CA mutations(12/20 vs 107/211,P = 0.37) or EBV infection(8/18 vs 103/211,P = 0.69).The frequency of pAkt expression was higher in cancers with exon20 mutations(100%) than in those with exon1(40%) or exon9(56%) mutations.One case showed both HER2 overexpression and EBV infection and 3 cases showed both PIK3CA mutations and EBV infection.However,no cases showed both PIK3CA mutations and HER2 overexpression.One EBVpositive cancer with PIK3CA mutation(H1047R) was MSI-positive.Three of these 4 cases were positive for pAkt expression.In survival analysis,pAkt expression significantly correlated with a poor prognosis(hazard ratio 1.75;95%CI:1.12-2.80,P = 0.02).CONCLUSION:HER2 expression,PIK3CA mutations and EBV infection in gastric cancer were characterized.pAkt expression significantly correlates with HER2 expression and with a poor prognosis.

Effects of small interfering RNA inhibit Class Ⅰ phosphoinositide 3-kinase on human gastric cancer cells

AIM: To investigate the effects of small interfering RNA (siRNA)-mediated inhibition of Class?I?phosphoinositide 3-kinase (Class?I?PI3K) signal transduction on the proliferation, apoptosis, and autophagy of gastric cancer SGC7901 and MGC803 cells.METHODS: We constructed the recombinant replication adenovirus PI3K(I)-RNA interference (RNAi)-green fluorescent protein (GFP) and control adenovirus NC-RNAi-GFP, and infected it into human gastric cancer cells. MTT assay was used to determine the growth rate of the gastric cancer cells. Activation of autophagy was monitored with monodansylcadaverine (MDC) staining after adenovirus PI3K(I)-RNAi-GFP and control adenovirus NC-RNAi-GFP treatment. Immunofluorescence staining was used to detect the expression of microtubule-associated protein 1 light chain 3 (LC3). Mitochondrial membrane potential was measured using the fluorescent probe JC-1. The expression of autophagy was monitored with MDC, LC3 staining, and transmission electron microscopy. Western blotting was used to detect p53, Beclin-1, Bcl-2, and LC3 protein expression in the culture supernatant.RESULTS: The viability of gastric cancer cells was inhibited after siRNA targeting to the Class?I?PI3K blocked Class?I?PI3K signal pathway. MTT assays revealed that, after SGC7901 cancer cells were treated with adenovirus PI3K(I)-RNAi-GFP, the rate of inhibition reached 27.48% ± 2.71% at 24 h, 41.92% ± 2.02% at 48 h, and 50.85% ± 0.91% at 72 h. After MGC803 cancer cells were treated with adenovirus PI3K(I)-RNAi-GFP, the rate of inhibition reached 24.39% ± 0.93% at 24 h, 47.00% ± 0.87% at 48 h, and 70.30% ± 0.86% at 72 h (P < 0.05 compared to control group). It was determined that when 50 MOI, the transfection efficiency was 95% ± 2.4%. Adenovirus PI3K(I)-RNAi-GFP (50 MOI) induced mitochondrial dysfunction and activated cell apoptosis in SGC7901 cells, and the results described here prove that RNAi of Class?I?PI3K induced apoptosis in SGC7901 cells. The results showed that adenovirus PI3K(I)-RNAi-GFP transfection induced punctate distribution of LC3 immunoreactivity, indicating increased formation of autophagosomes. The results showed that the basal level of Beclin-1 and LC3 protein in SGC7901 cells was low. After incubating with adenovirus PI3K(I)-RNAi-GFP (50 MOI), Beclin-1, LC3, and p53 protein expression was significantly increased from 24 to 72 h. We also found that Bcl-2 protein expression down-regulated with the treatment of adenovirus PI3K(I)-RNAi-GFP (50 MOI). A number of isolated membranes, possibly derived from ribosome-free endoplasmic reticulum, were seen. These isolated membranes were elongated and curved to engulf a cytoplasmic fraction and organelles. We used transmission electron microscopy to identify ultrastructural changes in SGC7901 cells after adenovirus PI3K(I)-RNAi-GFP (50 MOI) treatment. Control cells showed a round shape and contained normal-looking organelles, nucleus, and chromatin, while adenovirus PI3K(I)-RNAi-GFP (50 MOI)-treated cells exhibited the typical signs of autophagy.CONCLUSION: After the Class?I?PI3K signaling pathway has been blocked by siRNA, the proliferation of cells was inhibited and the apoptosis of gastric cancer cells was enhanced.

Herbal cake-partitioned moxibustion inhibits colonic autophagy in Crohn’s disease via signaling involving distinct classes of phosphatidylinositol 3-kinases

BACKGROUND Autophagy is an evolutionarily conserved biological process in eukaryotic cells that involves lysosomal-mediated degradation and recycling of related cellular components.Recent studies have shown that autophagy plays an important role in the pathogenesis of Crohn’s disease(CD).Herbal cake-partitioned moxibustion(HM)has been historically practiced to treat CD.However,the mechanism by which HM regulates colonic autophagy in CD remains unclear.AIM To observe whether HM can alleviate CD by regulating colonic autophagy and to elucidate the underlying mechanism.METHODS Rats were randomly divided into a normal control(NC)group,a CD group,an HM group,an insulin+CD(I+CD)group,an insulin+HM(I+HM)group,a rapamycin+CD(RA+CD)group,and a rapamycin+HM(RA+HM)group.2,4,6-trinitrobenzenesulfonic acid was administered to establish a CD model.The morphology of the colonic mucosa was observed by hematoxylin-eosin staining,and the formation of autophagosomes was observed by electron microscopy.The expression of autophagy marker microtubule-associated protein 1 light chain 3 beta(LC3B)was observed by immunofluorescence staining.Insulin and rapamycin were used to inhibit and activate colonic autophagy,respectively.The mRNA expression levels of phosphatidylinositol 3-kinase class I(PI3KC1),Akt1,LC3B,sequestosome 1(p62),and mammalian target of rapamycin(mTOR)were evaluated by RT-qPCR.The protein expression levels of interleukin 18(IL-18),tumor necrosis factor-α(TNF-α),nuclear factorκB/p65(NF-κB p65),LC3B,p62,coiled-coil myosin-like BCL2-interacting protein(Beclin-1),p-mTOR,PI3KC1,class III phosphatidylinositol 3-kinase(PI3KC3/Vps34),and p-Akt were evaluated by Western blot analysis.RESULTS Compared with the NC group,the CD group showed severe damage to colon tissues and higher expression levels of IL-18 and NF-κB p65 in colon tissues(P<0.01 for both).Compared with the CD group,the HM group showed significantly lower levels of these proteins(PIL-18<0.01 and Pp65<0.05).There were no significant differences in the expression of TNF-αprotein in colon tissue among the rat groups.Typical autophagic vesicles were found in both the CD and HM groups.The expression of the autophagy proteins LC3B and Beclin-1 was upregulated(P<0.01 for both)in the colon tissues of rats in the CD group compared with the NC group,while the protein expression of p62 and p-mTOR was downregulated(P<0.01 for both).However,these expression trends were significantly reversed in the HM group compared with the CD group(PLC3B<0.01,PBeclin-1<0.05,Pp62<0.05,and Pm-TOR<0.05).Compared with those in the RA+CD group,the mRNA expression levels of PI3KC1,Akt1,mTOR,and p62 in the RA+HM group were significantly higher(PPI3KC1<0.01 and PAkt1,mTOR,and p62<0.05),while those of LC3B were significantly lower(P<0.05).Compared with the RA+CD group,the RA+HM group exhibited significantly higher PI3KC1,p-Akt1,and pmTOR protein levels(PPI3KC1<0.01,Pp-Akt1<0.05,and Pp-mTOR<0.01),a higher p62 protein level(P=0.057),and significantly lower LC3B and Vps34 protein levels(P<0.01 for both)in colon tissue.CONCLUSION HM can activate PI3KC1/Akt1/mTOR signaling while inhibiting the PI3KC3(Vps34)-Beclin-1 protein complex in the colon tissues of CD rats,thereby inhibiting overactivated autophagy and thus exerting a therapeutic effect.

Phosphoinositide-3-kinase,catalytic,alpha polypeptide RNA interference inhibits growth of colon cancer cell SW948

AIM:To investigate the gene knock-down effect by the phosphoinositide-3-kinase,catalytic,alpha polypeptide(PIK3CA)-targeted double-stranded RNA(dsRNA) and its effect on cell proliferation and cycle distribution in SW948.METHODS:Two PIK3CA-targeted dsRNAs were constructed and transfected into SW948 cells.Transfections were performed using lipofectamine TM 2000.The transfection effectiveness was calculated basing on the rate of fluorescence cell of SW948 at 6 h after transfection.Total messenger RNA was extracted from these cells using the RNeasy kit,and semiquantitative reverse transcription polymerase chain reaction was performed to detect the down-regulation of PIK3CA,AKT1,MYC,and CCND1 gene expression.Cells were harvested,proteins were resolved,and western blot was employed to detect the expression levels of PIK3CA,AKT1,MYC,and CCND1 gene.Cell proliferation was assessed by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide assay and the inhibition rate was calculated.Soft agar colony formation assay was performed basing on colonies greater than 60 μm in diameter at ×100 magnification.The effect on cell cycle distribution and apoptosis was assessed by flow cytometry.All experiments were performed in triplicate.RESULTS:Green fluorescence was observed in SW948 cell transfected with plasmid Pgenesil-1,and the transfection effectiveness was about 65%.Forty-eight hours post-transfection,mRNA expression of PIK3CA in SW948 cells was 0.51 ± 0.04 vs 0.49 ± 0.03 vs 0.92 ± 0.01 vs 0.93 ± 0.03(P = 0.001) in Pgenesil-CA1,Pgenesil-CA2,negative and blank group respectively.mRNA expression of AKT1 was 0.50 ± 0.03 vs 0.48 ± 0.01 vs 0.93 ± 0.04 vs 0.92 ± 0.02(P = 0.000) in Pgenesil-CA1,Pgenesil-CA2,negative and blank group respectively.mRNA expression of MYC was 0.49 ± 0.01 vs 0.50 ± 0.04 vs 0.90 ± 0.02 vs 0.91 ± 0.03(P = 0.001) in the four groups respectively.mRNA expression of CCND1 was 0.45 ± 0.02 vs 0.51 ± 0.01 vs 0.96 ± 0.03 vs 0.98 ± 0.01(P = 0.001) in the four groups respectively.The protein level of PIK3CA was 0.53 ± 0.01 vs 0.54 ± 0.02 vs 0.92 ± 0.03 vs 0.91 ± 0.02(P = 0.001) in Pgenesil-CA1,Pgenesil-CA2,negative and blank group respectively.The protein level of AKT1 in the four groups was 0.49 ± 0.02 vs 0.55 ± 0.03 vs 0.94 ± 0.03 vs 0.95 ± 0.04,P = 0.000).The protein level of MYC in the four groups was 0.51 ± 0.03 vs 0.52 ± 0.04 vs 0.92 ± 0.02 vs 0.95 ± 0.01(P = 0.000).The protein level of CCND1 in the four groups was 0.54 ± 0.04 vs 0.56 ± 0.03 vs 0.93 ± 0.01 vs 0.93 ± 0.03(P = 0.000).Both Pgenesil-CA1 and Pgenesil-CA2 plasmids significantly suppressed the growth of SW948 cells when compared with the negative or blank group at 48 h after transfec-tion(29% vs 25% vs 17% vs 14%,P = 0.001),60 h after transfection(38% vs 34% vs 19% vs 16%,P = 0.001),and 72 h after transfection(53% vs 48% vs 20% vs 17%,P = 0.000).Numbers of colonies in negative,blank,CA1,and CA2 groups were 42 ± 4,45 ± 5,8 ± 2,and 10 ± 3,respectively(P = 0.000).There were more than 4.5 times colonies in the blank and negative control groups as there were in the CA1 and CA2 groups.In addition,the colonies in blank and negative control groups were also larger than those in the CA1 and CA2 groups.The percentage of cells in the CA1 and CA2 groups was significantly higher in G 0 /G 1 phase,but lower in S and G 2 /M phase when compared with the negative and control groups.Moreover,cell apoptosis rates in the CA1 and CA2 groups were 5.11 ± 0.32 and 4.73 ± 0.32,which were significantly higher than those in negative(0.95 ± 0.11,P = 0.000) and blank groups(0.86 ± 0.13,P = 0.001).No significant difference was found between CA1 and CA2 groups in cell cycle distribution and apoptosis.CONCLUSION:PIK3CA-targeted short hairpin RNAs can block the phosphoinositide 3-kinase-Akt signaling pathway and inhibit cell growth,increase apoptosis,and induce cell cycle arrest in the PIK3CA-mutant colon cancer SW948 cells.

Phosphoinositide 3-Kinase/Akt and Nuclear Factor-κB Are Involved in Staphylococcus Aureus-induced Apoptosis in U937 Cells

Objective To explore the mechanisms involved in Staphylococcus aureus （S. aureus） invading human monocytic U937 cells. Methods S. aureus were added to U937 cells at multiplicity of infections （MOI） of 20：1 for 0, 15, 30, 60, and 90 minutes, respectively. Cell apoptosis was analyzed with Hoechst 33258 staining and Annexin V-fluorescein isothiocyanate （FITC）/propidium iodide （PI） flow cytometry analysis. Akt and nuclear factor-κB （NF-κB） activities were detected by Western blotting. Results Infection of U937 cells with S. aureus induced rapid cell death in a time-dependent manner, and the cells displayed characteristic features of apoptosis. S. aureus-induced apoptosis was associated with a prominent downregulation of activated （phosphorylated） Akt and NF-κB. The inhibition of phosphorylated Akt by LY294002 led to the inhibition of NF-κB in a dose-dependent manner. Inhibition of Akt with LY294002 caused further increase in apoptosis of U937 cells. Conclusions S. aureus can stimulate the apoptosis of U937 ceils. S. aureus induces apoptosis of U937 cells by inhibiting Akt-regulated NF-κB.

Alisol B acetate induces apoptosis of SGC7901 cells via mitochondrial and phosphatidylinositol 3-kinases/Akt signaling pathways

AIM： To examine the effect of alisol B acetate on the growth of human gastric cancer cell line SGC7901 and its possible mechanism of action.METHODS： The cytotoxic effect of alisol B acetate on SGC7901 cells was measured by 3-（4,5-dimethylthiazol- 2-yl）-2,5-diphenyltetrazolium bromide （MI-I-） assay. Phase-contrast and electron microscopy were used to observe the morphological changes. Cell cycle and mitochondrial transmembrane potential （A^Pm） were determined by flow cytometry. Western blotting was used to detect the expression of apoptosis-regulated gene Bcl-2, Bax, Apaf-1, caspase-3, caspase-9, Akt, P-Akt and phosphatidylinositol 3-kinases （PI3K）.RESULTS： Alisol B acetate inhibited the proliferation of SGC7901 cell line in a time- and dose-dependent manner. PI staining showed that alisol B acetate can change the cell cycle distribution of SGC7901, increase the proportion of cells in G0-G1 phase and decrease the proportion of S phase cells and G2-M phase cells. Alisol B acetate at a concentration of 30 pmol/L induced apoptosis after 24, 48 and 72 h incubation, with occurrence rates of apoptotic cells of 4.36%, 14.42% and 21.16%, respectively. Phase-contrast and electron microscopy revealed that the nuclear fragmentation and chromosomal condensed, cells shrank and attachment loss appeared in the SGC7901 treated with alisol B acetate. Apoptosis of SGC7901 cells was associated with cell cycle arrest, caspase-3 and caspase-9 activation, loss of mitochondrial membrane potential and up-regulation of the ratio of Bax/Bcl-2 and inhibition of the PI3K/Akt.CONCLUSION： Alisol B acetate exhibits an antiproliferative effect in SGC7901 cells by inducing apoptosis. Apoptosis of SGC7901 cells involves mitochondria-caspase and PI3K/Akt dependent pathways.

Analysis of Phosphatidylinositol 3-kinase Activation in the Adipose Tissue of Gestational Diabetes Mellitus Patients and Insulin Resistance

The P85 regulatory subunit protein and gene expression and P110 catalylic subunit activity of phosphatidylinositol 3-kinase (PI-3K) were investigated in adipose tissue of patients with gestational diabetes mellitus (GDM) in order to explore the molecular mechanisms of insulin resistance (IR) of GDM. Samples from patients with GDM (n=50), and controls (n=50) were collected. Fasting insulin (FIN) was determined by radioimmunoassay. Fasting plasma glucose (FPG) was measured by oxidase assay. Western blot technique was used to detect the levels of PI-3K P85 subunit in adipose tissues of patients with GDM. The mRNA expression of PI-3K P85 subunit was detected by reverse transcription polymerase chain reaction (RT-PCR) method in the adipose tissue. PI-3K activity was examined by immunoprecipitation, thin-layer chromatography and gamma scintillation counting. The results were analyzed statistically. It was found that the levels of FPG, FIN and HOMA-IR in GDM group were significantly higher than those in control group (all P0.05). PI-3K activity was significantly decreased to 82.89% in GDM group as compared with control group (P<0.01) and negatively correlated with HOMA-IR (r=-0.75, P<0.01). It was concluded that PI-3K in GDM patients may be involved in the insulin signaling pathway, resulting in IR of GDM.

Phosphatidylinositol 3-kinase CB association with preoperative radiotherapy response in rectal adenocarcinoma

AIM: To examine the correlation of phosphatidylinositol 3-kinase (PIK3) CB expression with preoperative radiotherapy response in patients with stage II/III rectal adenocarcinoma.

Protective effects of panax notoginseng saponin on dextran sulfate sodium-induced colitis in rats through phosphoinositide-3-kinase protein kinase B signaling pathway inhibition

BACKGROUND Intestinal inflammation is a common digestive tract disease, which is usually treated with hormone medicines. Hormone medicines are effective to some extent, but long-term use of them may bring about many complications.AIM To explore the protective effects of panax notoginseng saponin(PNS) against dextran sulfate sodium(DSS)-induced intestinal inflammatory injury through phosphoinositide-3-kinase protein kinase B(PI3K/AKT) signaling pathway inhibition in rats.METHODS Colitis rat models were generated via DSS induction, and rats were divided into control(no modeling), DSS, DSS + PNS 50 mg/k, and DSS + PNS 100 mg/kg groups. Then, the intestinal injury, oxidative stress parameters, inflammatory indices, tight junction proteins, apoptosis, macrophage polarization, and TLR4/AKT signaling pathway in colon tissues from rats in each of the groups were detected. The PI3 K/AKT signaling pathway in the colon tissue of rats was blocked using the PI3K/AKT signaling pathway inhibitor, LY294002.RESULTS Compared with rats in the control group, rats in the DSS group showed significantly shortened colon lengths, and significantly increased disease activity indices, oxidative stress reactions and inflammatory indices, as well as significantly decreased expression of tight junction-associated proteins. In addition, the DSS group showed significantly increased apoptotic cell numbers,and showed significantly increased M1 macrophages in spleen and colon tissues.They also showed significantly decreased M2 macrophages in colon tissues, as well as activation of the PI3K/AKT signaling pathway(all P < 0.05). Compared with rats in the DSS group, rats in the DSS + PNS group showed significantly lengthened colon lengths, decreased disease activity indices, and significantly alleviated oxidative stress reactions and inflammatory responses. In addition, this group showed significantly increased expression of tight junction-associated proteins, significantly decreased apoptotic cell numbers, and significantly decreased M1 macrophages in spleen and colon tissues. This group further showed significantly increased M2 macrophages in colon tissues, and significantly suppressed activation of the PI3K/AKT signaling pathway, as well as a dose dependency(all P < 0.05). When the PI3K/AKT signaling pathway was inhibited, the apoptosis rate of colon tissue cells in the DSS + LY294002 group was significantly lower than that of the DSS group(P < 0.05).CONCLUSION PNS can protect rats against DSS-induced intestinal inflammatory injury by inhibiting the PI3K/AKT signaling pathway, and therefore may be potentially used in the future as a drug for colitis.