PI3K signaling pathway targeting by using different molecular approaches to treat cancer

Recent evidence of research has been proposed that the phosphoinositide 3-kinase (PI3K) pathway is noticeable target for searching novel anticancer agents.The phosphoinositide 3-kinase (PI3K) is accountable for harmonizing a diverse range of cell functions,such as transcription,proliferation,cell survival,cell growth,degranulation,vesicular trafficking and cell migration,which are mostly involved in carcinogenesis.Particularly,PI3K-mediated signaling molecules and its effects on gene expression contribute to tumorigenesis.PI3Ks generally are grouped into three distinct classes:Ⅰ,Ⅱ and Ⅲ according to their structure and function.The class ⅠA of PI3K includes an alpha,beta or delta p110 catalytic subunit (p110α,p 110β,or p110γ),which are associated with the activation of RTKs.Mutations in PIK3CA,the gene encoding the p110α catalytic subunit of PI3K,have just been recognized as novel mechanisms of inducing oncogenic PI3K signaling.Therefore,the class ⅠA PI3K is the only one of most evidently implicated in cancer.The PI3K pathway is mostly mutated in more cancer patients compared with normal person,making it an eye-catching molecular target for analyses based on inhibitor molecule.In this article,we highlighted the signaling effects and regulation pathway of PI3K involved in the development and survival of tumor cells.The consequence and intricacy of PI3K pathway made it an essential beneficial target for cancer treatment.

Objective. The present study investigated the role of calcineurin in angiotensin II(AngII) induced cardiac myocyte hypertrophy of rats. Method. The primary cardiac myocytes were cultured under the standard conditions. The calcineurin activity in AngII treated cardiomyocytes was tested by using PNPP;protein synethsis rate was assessed by 3H leucine incorporation; atrial natriuretic factor(ANF) Mrna level was determined by Northern blot analysis. Cell viability was estimated by lactate dehydrogenase(LDH) levels in cultured medium and by dyed cell numbers. Result. After stimulation of 10,100 and 1 000nmol/L of AngII, calcineurin activities in the cardiomyocytes were increased by 13％ ,57％ (P< 0.05) and 228％ (P< 0.01) respectively, compared with control group. Cyclosporin A(CsA), a specific inhibitor of calcineurin, markedly inhibited the calcineurin activity and decreased the 3H leucine incorporation in AngII treated cardiomyocytes in a dose dependent manner. It was also found that CsA slightly reduced the Mrna level of ANF gene in AngII stimulated cardiomyocytes. Conclusion. During AngII induced cardiac myocyte hypertrophy, calcineurin signal pathway is activated, and inhibition of the pathway can attenuate AngII induced cardiac myocyte hypertrophy, which suggests that the calcineurin signal pathway may play an important role in AngII induced myocardial hypertrophy of rats.

PI3K/Akt/mTOR信号转导通路与卵巢癌研究进展

Angiotensin-converting enzyme 2 (ACE2)-angiotensin (1-7) [Ang (1-7)]-Mas constitutes the vasoprotective axis and is demon-strated to antagonize the vascular pathophysiological effects of the classical renin -angiotensin system .We hypothesize that upregulation of ACE2-Ang (1-7) signaling protects endothelial function through reducing oxidative stress , thus resulting in beneficial outcome in di-abetes.Ex vivo treatment with Ang (1-7) augmented endothelium-dependent relaxation (EDR) in renal arteries from diabetic patients . Both Ang (1-7) infusion via osmotic pump (500 ng? kg -1? min-1 ) for 2 weeks and exogenous ACE 2 overexpression mediated by ad-enoviral ACE2 via tail vein injection rescued the impaired EDR and flow-mediated dilatation ( FMD) in db/db mice.Diminazene acetu-rate treatment (15 mg? kg-1? d-1 ) activated ACE2, increased the circulating Ang (1-7) level, and augmented EDR and FMD in db/db mouse arteries.In addition, activation of the ACE2-Ang (1-7) axis reduced reactive oxygen species (ROS) overproduction de-termined by dihydroethidium staining , CM-H2DCFDA fluorescence imaging , and chemiluminescence assay in db/db mouse aortas and also in high-glucose-treated endothelial cells .Pharmacological benefits of ACE 2-Ang ( 1-7 ) upregulation on endothelial function were confirmed in ACE2 knockout mice both ex vivo and in vitro.We elucidate that the ACE2-Ang (1-7)-Mas axis serves as an important signal pathway in endothelial cell protection in diabetic mice , especially in diabetic human arteries .In summary, endogenous ACE2-Ang (1-7) activation or ACE2 overexpression preserves endothelial function in diabetic mice through increasing nitric oxide bioavail -ability and inhibiting oxidative stress , suggesting the therapeutic potential of ACE 2-Ang(1-7) axis activation against diabetic vasculop-athy.

Mitogenic and Anti-apoptotic Effects of Insulin in En-dometrial Cancer Cells Are Phosphatidylinositol 3-ki-nase/Akt Dependent

Background and objective Endometrial carcinoma is the most common gynecologic malignancy in the world. Although the insulin-resistant state or hyperinsulinemia was recently suggested as a potent risk factor for endometrial carcinogenesis and progression, there is only limited supporting evidence and the mechanism is unclear. In this study, we explored the roles of phosphatidylinositol 3-k/nase (PI3K)/Akt signaling pathway in the response of a human endometrial cancer cell line, Ishikawa3-H-12 cells, to insulin.Methods The Ishikawa 3-H-12 cells were serum-starved and then stimulated by insulin at various concentrations and for different time periods. To identify the insnlin-mediated signal pathway in the cells, LY294002, a selective inhibitor of PI3K, was used. The proliferation and the apoptotic rates were determined with methyl thiazolyl tetrazolium (MTT) and flow cytometric assays, respectively.Results The insulin receptor positive Ishikawa 3-H-12 cells had enhanced proliferation upon insulin stimulation in a rinse-and time-dependent manner. The growth promoting effect of insulin was blocked when the cells were pre-incubated with LY294002 for 60 rains.Insulin was able to protect the cells from serum-starvation-induced apoptosis in a concentration-dependent manner, while the anti-apoptotic effects of insulin was reversed by adding LY294002. Treatment with insulin at 1 μM for 15 rain resulted in an increased level of activated Akt The insulin-induced Akt activation was inhibited by LY294002 in a dose-dependent manner.Conclusion Insulin activates PI3K/Akt signaling pathway and is a mitogenic and anti-apoptotic agent for Ishikewa 3-H-12 endometrial cancer cells.

Objective:　To study the rule of ERK1/2 activity and regulative effect of ERK1/2 pathway on the production of pro-inflammatory cytokine TNFα in mice Kupffer cells (mKC) induced by LPS, and to exploring novel methods to prevent and treat clinical patients of endotoxemia.　　Methods:　Immunoprecipitate kinase assay and Western blotting analysis were used to detect the phosphorylated ERK1/2 kinase activity in mKC stimulated by LPS, and ELISA was used to study the effect of ERK1/2 signaling cascade on LPS-induced TNFα production in mKC.　　Results:　In mKC, LPS treatment resulted in transient and rapid increase of kinase activity of ERK1/2 that phosphorylated their specific substrate ELK-1, with maximal value at 30 minutes and a return near to baseline within 2 hours, and LPS-induced ERK1/2 activity from LPS concentration of 10 pg/ml to the top activity at 100 ng/ml. No activity was observed in unstimulated mKC. Inhibition of the ERK1/2 pathway using the specific ERK1/2 signal pathway inhibitor PD98059 caused a marked and concentration-dependent reduction of TNFα production.　　Conclusions:　The results show that LPS can markedly activate ERK1/2 pathway in mKC. PD98059 causes a significant and concentration-dependent reduction of TNFα production. ERK1/2 may be a novel target to treat clinical patient of endotoxemia.

过氧化氢通过激活氧化应激诱导成骨细胞凋亡

目的：探讨氧化应激状态诱导成骨细胞系 MC3T3-E1凋亡中线粒体途径的作用。方法：采用 MTT 法检测不同浓度过氧化氢处理后 MC3T3-E1的增殖情况；Annexin V-FITC/PI流式细胞学检测细胞凋亡；JC-1流式细胞学检测线粒体膜电位；DCFH-DA流式检测ROS活性。结果：MC3T3-E1过氧化氢处理后，细胞增殖明显抑制呈剂量效应关系，ROS 活性和凋亡增加，线粒体膜电位降低。结论：过氧化氢可以增加细胞内 ROS 水平，通过激活线粒体途径诱导细胞凋亡。