Multiple implications of 3-phosphoinositide-dependent protein kinase 1 in human cancer

3-phosphoinositide-dependent protein kinase-1(PDK1) is a central mediator of cellular signaling between phosphoinositide-3 kinase and various intracellular serine/threonine kinases,including protein kinase B,p70 ribosomal S6 kinase,serum and glucocorticoid-inducible kinase,and protein kinase C.PDK1 activates members of the AGC family of protein kinases by phosphorylating serine/threonine residues in the activation loop.Here,we review the regulatory mechanisms of PDK1 and its roles in cancer.PDK1 is activated by autophosphorylation in the activation loop and other serine residues,as well as by phosphorylation of Tyr-9 and Tyr-373/376.Src appears to recognize PDK1 following tyrosine phosphorylation.The role of heat shock protein 90 in regulating PDK1 stability and PDK1-Src complex formation are also discussed.Furthermore,we summarize the subcellular distribution of PDK1.Finally,an important role for PDK1 in cancer chemotherapy is proposed.In conclusion,a better understanding of its molecular regulatory mechanisms in various signaling pathways will help to explain how PDK1 acts as an oncogenic kinase in various cancers,and will contribute to the development of novel cancer chemotherapies.

Loss of monopolar spindle-binding protein 3B expression promotes colorectal cancer malignant behaviors by activation of target of rapamycin kinase/autophagy signaling

BACKGROUND Monopolar spindle-binding protein 3B(MOB3B)functions as a signal transducer and altered MOB3B expression is associated with the development of human cancers.AIM To investigate the role of MOB3B in colorectal cancer(CRC).METHODS This study collected 102 CRC tissue samples for immunohistochemical detection of MOB3B expression for association with CRC prognosis.After overexpression and knockdown of MOB3B expression were induced in CRC cell lines,changes in cell viability,migration,invasion,and gene expression were assayed.Tumor cell autophagy was detected using transmission electron microscopy,while nude mouse xenograft experiments were performed to confirm the in-vitro results.RESULTS MOB3B expression was reduced in CRC vs normal tissues and loss of MOB3B expression was associated with poor CRC prognosis.Overexpression of MOB3B protein in vitro attenuated the cell viability as well as the migration and invasion capacities of CRC cells,whereas knockdown of MOB3B expression had the opposite effects in CRC cells.At the molecular level,microtubule-associated protein light chain 3 II/I expression was elevated,whereas the expression of matrix metalloproteinase(MMP)2,MMP9,sequestosome 1,and phosphorylated mechanistic target of rapamycin kinase(mTOR)was downregulated in MOB3B-overexpressing RKO cells.In contrast,the opposite results were observed in tumor cells with MOB3B knockdown.The nude mouse data confirmed these in-vitro findings,i.e.,MOB3B expression suppressed CRC cell xenograft growth,whereas knockdown of MOB3B expression promoted the growth of CRC cell xenografts.CONCLUSION Loss of MOB3B expression promotes CRC development and malignant behaviors,suggesting a potential tumor suppressive role of MOB3B in CRC by inhibition of mTOR/autophagy signaling.

Mismatched effects of receptor interacting protein kinase-3 on hepatic steatosis and inflammation in nonalcoholic fatty liver disease

AIM To validate the effects of receptor interacting protein kinase-3(RIP3) deletion in non-alcoholic fatty liver disease(NAFLD) and to clarify the mechanism of action.METHODS Wild-type(WT) and RIP3 knockout(KO) mice werefed normal chow and high fat(HF) diets for 12 wk. The body weight was assessed once weekly. After 12 wk, the liver and serum samples were extracted. The liver tissue expression levels of RIP3, microsomal triglyceride transfer protein, protein disulfide isomerase, apolipoprotein-B, X-box binding protein-1, sterol regulatory element-binding protein-1c, fatty acid synthase, cluster of differentiation-36, diglyceride acyltransferase, peroxisome proliferator-activated receptor alpha, tumor necrosis factor-alpha(TNF-α), and interleukin-6 were assessed. Oleic acid treated primary hepatocytes from WT and RIP3 KO mice were stained with Nile red. The expression of inflammatory cytokines, including chemokine(C-X-C motif) ligand(CXCL) 1, CXCL2, and TNF-α, in monocytes was evaluated.RESULTS RIP3 KO HF diet fed mice showed a significant gain in body weight, and liver weight, liver to body weight ratio, and liver triglycerides were increased in HF diet fed RIP3 KO mice compared to HF diet fed WT mice. RIP3 KO primary hepatocytes also had increased intracellular fat droplets compared to WT primary hepatocytes after oleic acid treatment. RIP3 overexpression decreased hepatic fat content. Quantitative real-time polymerase chain reaction analysis showed that the expression of very-low-density lipoproteins secretion markers(microsomal triglyceride transfer protein, protein disulfide isomerase, and apolipoprotein-B) was significantly suppressed in RIP3 KO mice. The overall NAFLD Activity Score was the same between WT and RIP3 KO mice; however, RIP3 KO mice had increased fatty change and decreased lobular inflammation compared to WT mice. Inflammatory signals(CXCL1/2, TNF-α, and interleukin-6) increased after lipopolysaccharide and pancaspase inhibitor(necroptotic condition) treatment in monocytes. Neutrophil chemokines(CXCL1, and CXCL2) were decreased, and TNF-α was increased after RIP3 inhibitor treatment in monocytes.CONCLUSION RIP3 deletion exacerbates steatosis, and partially inhibits inflammation in the HF diet induced NAFLD model.

Neuroprotective mechanisms of rutin for spinal cord injury through anti-oxidation and anti-inflammation and inhibition of p38 mitogen activated protein kinase pathway

Rutin has anti-inflammatory, antioxidant, anti-viral, anti-tumor and immune regulatory effects. However, the neuroprotective effects of rutin in spinal cord injury are unknown. The p38 mitogen activated protein kinase （p38 MAPK） pathway is the most important member of the MAPK family that controls inflammation. We assumed that the mechanism of rutin in the repair of spinal cord injury is associated with the inhibition of p38 MAPK pathway. Allen’s method was used to establish a rat model of spinal cord injury. The rat model was intraperitoneally injected with rutin （30 mg/kg） for 3 days. After treatment with rutin, Basso, Beattie and Bresnahan locomotor function scores increased. Water content, tumor necrosis factor alpha, interleukin 1 beta, and interleukin 6 levels, p38 MAPK protein expression and caspase-3 and -9 activities in T8–9 spinal cord decreased. Oxidative stress related markers superoxide dismutase and glutathione peroxidase levels increased in peripheral blood. Rutin exerts neuroprotective effect through anti-oxidation, anti-inflammation, anti-apoptosis and inhibition of p38 MAPK pathway.

Fenofibrate Pre-treatment Suppressed Inflammation by Activating Phosphoinositide 3 Kinase/Protein Kinase B(PI3K/Akt) Signaling in Renal Ischemia-Reperfusion Injury

The aim of this study was to investigate the possible beneficial effects of Fenofibrate on renal ischemia-reperfusion injury（IRI） in mice and its potential mechanism. IRI was induced by bilateral renal ischemia for 60 min followed by reperfusion for 24 h. Eighteen male C57BL/6 mice were randomly divided into three groups： sham-operated group（sham）, IRI＋saline group（IRI group）, IRI＋Fenofibrate（FEN） group. Normal saline or Fenofibrate（3 mg/kg） was intravenously injected 60 min before renal ischemia in IRI group and FEN group, respectively. Blood samples and renal tissues were collected at the end of reperfusion. The renal function, histopathologic changes, and the expression levels of pro-inflammatory cytokines [interleukin-8（IL-8）, tumor necrosis factor alpha（TNF-α） and IL-6] in serum and renal tissue homogenate were assessed. Moreover, the effects of Fenofibrate on activating phosphoinositide 3 kinase/protein kinase B（PI3K/Akt） signaling and peroxisome proliferator-activated receptor-α（PPAR-α） were also measured in renal IRI. The results showed that plasma levels of blood urea nitrogen and creatinine, histopathologic scores and the expression levels of TNF-α, IL-8 and IL-6 were significantly lower in FEN group than in IRI group. Moreover, Fenofibrate pretreatment could further induce PI3K/Akt signal pathway and PPAR-α activation following renal IRI. These findings indicated PPAR-α activation by Fenofibrate exerts protective effects on renal IRI in mice by suppressing inflammation via PI3K/Akt activation. Thus, Fenofibrate could be a novel therapeutic alternative in renal IRI.

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.

The calmodulin-dependent protein kinase II inhibitor KN-93 protects rat cerebral cortical neurons from N-methyl-D-aspartic acid-induced injury

In this study, primary cultured cerebral cortical neurons of Sprague-Dawley neonatal rats were treated with 0.25, 0.5, and 1.0 μM calmodulin-dependent protein kinase II inhibitor KN-93 after 50 μM N-methyI-D-aspartic acid-induced injury. Results showed that, compared with N-methyi-D- aspartic acid-induced injury neurons, the activity of cells markedly increased, apoptosis was significantly reduced, leakage of lactate dehydrogenase decreased, and intracellular Ca2＋ concentrations in neurons reduced after KN-93 treatment. The expression of caspase-3, phosphorylated calmodulin-dependent protein kinase II and total calmodulin-dependent protein kinase II protein decreased after KN-93 treatment. And the effect was apparent at a dose of 1.0 pM KN-93. Experimental findings suggest that KN-93 can induce a dose-dependent neuroprotective effect, and that the underlying mechanism may be related to the down-regulation of caspase-3 and calmodulin- dependent protein kinase II expression.

Micro RNA-21 promotes phosphatase gene and protein kinase B/phosphatidylinositol 3-kinase expression in colorectal cancer

AIM: To explore the regulatory mechanism of the target gene of micro RNA-21(mi R-21), phosphatase gene(p TEN), and its downstream proteins, protein kinase B(AKT) and phosphatidylinositol 3-kinase(p I3K), in colorectal cancer(CRC) cells. METHODS: Quantitative real-time p CR(q RT-p CR) and Western blot were used to detect the expression levels of mi R-21 and p TEN in HCT116, HT29, Colo32 and SW480 CRC cell lines. Also, the expression levels of p TEN m RNA and its downstream proteins AKT and p I3 K in HCT116 cells after downregulating mi R-21 were investigated. RESULTS: Comparing the mi R-21 expression in CRC cells, the expression levels of mi R-21 were highest in HCT116 cells, and the expression levels of mi R-21 were lowest in SW480 cells. In comparing mi R-21 and p TEN expression in CRC cells, we found that the protein expression levels of mi R-21 and p TEN were inversely correlated(p < 0.05); when mi R-21 expression was reduced, m RNA expression levels of p TEN did not significantly change(p > 0.05), but the expression levels of its protein significantly increased(p < 0.05). In comparing the levels of p TEN protein and downstream AKT and p I3 K in HCT116 cells after downregulation of mi R-21 expression, the levels of AKT and p I3 K protein expression significantly decreased(p < 0.05). CONCLUSION: p TEN is one of the direct target genesof mi R-21. Thus, phosphatase gene and its downstream AKT and p I3 K expression levels can be regulated by regulating the expression levels of mi R-21, which in turn regulates the development of CRC.

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.

PI3K/AKT signaling and neuroprotection in ischemic stroke:molecular mechanisms and therapeutic perspectives

It has been reported that the PI3K/AKT signaling pathway plays a key role in the pathogenesis of ischemic stroke.As a result,the development of drugs targeting the PI3K/AKT signaling pathway has attracted increasing attention from researchers.This article reviews the pathological mechanisms and advancements in research related to the signaling pathways in ischemic stroke,with a focus on the PI3K/AKT signaling pathway.The key findings include the following:(1)The complex pathological mechanisms of ischemic stroke can be categorized into five major types:excitatory amino acid toxicity,Ca^(2+)overload,inflammatory response,oxidative stress,and apoptosis.(2)The PI3K/AKT-mediated signaling pathway is closely associated with the occurrence and progression of ischemic stroke,which primarily involves the NF-κB,NRF2,BCL-2,mTOR,and endothelial NOS signaling pathways.(3)Natural products,including flavonoids,quinones,alkaloids,phenylpropanoids,phenols,terpenoids,and iridoids,show great potential as candidate substances for the development of innovative anti-stroke medications.(4)Recently,novel therapeutic techniques,such as electroacupuncture and mesenchymal stem cell therapy,have demonstrated the potential to improve stroke outcomes by activating the PI3K/AKT signaling pathway,providing new possibilities for the treatment and rehabilitation of patients with ischemic stroke.Future investigations should focus on the direct regulatory mechanisms of drugs targeting the PI3K/AKT signaling pathway and their clinical translation to develop innovative treatment strategies for ischemic stroke.

Human neural stem cell-derived extracellular vesicles protect against ischemic stroke by activating the PI3K/AKT/mTOR pathway

Human neural stem cell-derived extracellular vesicles exhibit analogous functions to their parental cells,and can thus be used as substitutes for stem cells in stem cell therapy,thereby mitigating the risks of stem cell therapy and advancing the frontiers of stem cell-derived treatments.This lays a foundation for the development of potentially potent new treatment modalities for ischemic stroke.However,the precise mechanisms underlying the efficacy and safety of human neural stem cell-derived extracellular vesicles remain unclear,presenting challenges for clinical translation.To promote the translation of therapy based on human neural stem cell-derived extracellular vesicles from the bench to the bedside,we conducted a comprehensive preclinical study to evaluate the efficacy and safety of human neural stem cell-derived extracellular vesicles in the treatment of ischemic stroke.We found that administration of human neural stem cell-derived extracellular vesicles to an ischemic stroke rat model reduced the volume of cerebral infarction and promoted functional recovery by alleviating neuronal apoptosis.The human neural stem cell-derived extracellular vesicles reduced neuronal apoptosis by enhancing phosphorylation of phosphoinositide 3-kinase,mammalian target of rapamycin,and protein kinase B,and these effects were reversed by treatment with a phosphoinositide 3-kinase inhibitor.These findings suggest that human neural stem cell-derived extracellular vesicles play a neuroprotective role in ischemic stroke through activation of phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin signaling pathway.Finally,we showed that human neural stem cell-derived extracellular vesicles have a good in vivo safety profile.Therefore,human neural stem cell-derived extracellular vesicles are a promising potential agent for the treatment of ischemic stroke.

PI3K-like Kinases Restrain Pim Gene Expression in Endothelial Cells

Pim kinases contribute to tumor formation and development of lymphoma,which shows enhanced DNA replication,DNA recombination and repair.Endothelial cells (ECs) express all the three members of Pim kinase gene family.We hypothesized that DNA repair gene would regulate Pim ex-pression in ECs.Human umbilical vein endothelial cells (HUVECs) were isolated and maintained in M199 culture medium.The cellular distribution of Pim-3 in ECs was determined by immunofluorescent staining.The siRNA fragments were synthesized and transfected by using Lipofectamine LTX.The total cellular RNA was extracted from the cells by using Trizol reagent.cDNAs were quantified by semi-quantity PCR.The effects of LY294002 and wortmannin on RNA stability in ECs were also ex-amined.Our data showed that LY294002 and wortmannin,phosphatidylinositol 3-kinase (PI3K) and PI3K-like kinase inhibitors,increased Pim mRNA expression in ECs without altering the mRNA stabil-ity.RNA interference (RNAi) targeting DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and ataxia telangiectasia mutated (ATM) increased mRNA expression of Pim-3 and Pim-1,respectively.Silencing of Akt decreased Pim-1 instead of Pm-2 and Pim-3 gene expression in ECs.But etoposide,a nucleoside analogue,which could activate DNA-PKcs and ATM,increased Pim expression in ECs.Our study indicates that the expression of Pim kinases is physiologically related to DNA-PKcs and ATM in ECs.

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.

INHIBITION OF IL-6-INDUCED STAT3 ACTIVATION IN MYELOMA CELLS BY PROTEIN KINASE A

Objective: To investigate the regulation effect of protein kinase A on IL-6-induced STAT3 activation in myeloma cells. Methods: Two human myeloma cell lines-Sko-007 and U266 were pretreated with Forskolin, a protein kinase A antagonist, and then stimulated by IL-6. The activation state of STAT3 in these two cells were examined by electrophoretic mobility shift assay (EMSA). Results: Although PKA pathway itself doesn’t participate in IL-6 signal transduction in Sko-007 and U266 cells, activation of protein kinase A can inhibit IL-6-induced STAT3 activation in these two cell lines. Conclusion: There exists an inhibitory effect of protein kinase A on STAT3 activation in human myeloma cells treated by IL-6.

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.

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.

miR-212-3p靶向MAPK3调控骨髓间充质干细胞的衰老

背景:骨质疏松症患者的骨髓间充质干细胞表现出明显衰老状态,并且细胞活性及成骨分化水平显著降低。miR-212-3p能够抑制人骨髓间充质干细胞的成骨分化,但其对骨髓间充质干细胞衰老调控的作用及机制尚不明确。目的:研究miR-212-3p通过靶向丝裂原活化蛋白激酶3(mitogen-activated protein kinase 3,MAPK3)对骨髓间充质干细胞衰老的影响及其机制。方法:体外分离培养大鼠骨髓间充质干细胞,收集第3代进行以下实验:①分2组培养:对照组加入完全培养基,造模组加入含H_(2)O_(2)的完全培养基培养,培养72 h后,检测细胞中β-半乳糖苷酶活性、miR-212-3p和MAPK3 mRNA表达,以及MAPK3、p16和p21蛋白表达。②分3组培养:对照组、抑制物对照组、miR-212-3p抑制物组,转染24 h后,检测细胞中miR-212-3p、MAPK3 mRNA表达及MAPK3蛋白表达。③采用双荧光素酶报告基因联合qRT-PCR和Western blot验证miR-212-3p与MAPK3靶向调控作用。④分组培养:分为对照抑制物组、miR-212-3p抑制物组、miR-212-3p抑制物+干扰对照组、miR-212-3p抑制物+MAPK3干扰组,转染24 h后,检测细胞中MAPK蛋白与mRNA表达。分为对照组、H_(2)O_(2)组、H_(2)O_(2)+对照抑制物组、H_(2)O_(2)+miR-212-3p抑制物组、H_(2)O_(2)+miR-212-3p抑制物+干扰对照组、H_(2)O_(2)+miR-212-3p抑制物+MAPK3干扰组,细胞转染24 h后再加入H_(2)O_(2)培养72 h,检测细胞中衰老相关β-半乳糖苷酶活性、p16和p21蛋白表达。结果与结论:①与对照组比较,造模组β-半乳糖苷酶活性、miR-212-3p mRNA表达及p16、p21蛋白表达升高(P<0.05),MAPK3 mRNA和蛋白表达降低(P<0.05)。②与对照组比较,miR-212-3p抑制物组细胞中miR-212-3p mRNA表达降低(P<0.05),MAPK3 mRNA与蛋白表达升高(P<0.05)。③双荧光素酶报告基因实验证实,MAPK3是miR-212-3p下游靶基因。④与对照抑制物组比较,miR-212-3p抑制物组细胞中MAPK3 mRNA和蛋白表达升高(P<0.05);与miR-212-3p抑制物组比较,miR-212-3p抑制物+MAPK3干扰组细胞中MAPK3 mRNA和蛋白表达降低(P<0.05)。与H_(2)O_(2)+对照抑制物组比较,H_(2)O_(2)+miR-212-3p抑制物组β-半乳糖苷酶活性降低(P<0.05);与H_(2)O_(2)+miR-212-3p抑制物组比较,H_(2)O_(2)+miR-212-3p抑制物+MAPK3干扰组β-半乳糖苷酶活性升高(P<0.05)。与H_(2)O_(2)+对照抑制物组比较,H_(2)O_(2)+miR-212-3p抑制物组细胞中p16和p21蛋白表达降低(P<0.05);与H_(2)O_(2)+miR-212-3p抑制物组比较,H_(2)O_(2)+miR-212-3p抑制物+MAPK3干扰组细胞中p16和p21蛋白表达升高(P<0.05)。⑤结果表明,下调miR-212-3p可抑制大鼠骨髓间充质干细胞衰老,其作用机制可能是通过靶向上调MAPK3表达实现的。

Involvement of ERK1/2 and p38 MAPK in up-regulation of 14-3-3 protein induced by hydrogen peroxide preconditioning in PC12 cells

Objective To investigate the protective effects of hydrogen peroxide preconditioning （HPP） on the pheochromocytoma （PC12） cells treated with 1-methyl-4-phenylpyridinium （MPP^＋） and to explore the potential mechanisms. Methods The viability and apoptosis of PC 12 cells were determinded by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay and 4′,6′-diamidino-2-phenylindole （DAPI） staining, respectively. The expressions of 14-3-3 protein and phospholylated p38 mitogen-activated protein kinase （MAPK） were determined by Western blot. Enzyme-linked immunosorbent assay （ELISA） was used to measure the activity of extracellular signal-regulated protein kinase 1/2 （ERK1/2）. Results The cell viability decreased and the number of apoptotic cells increased dramatically in MPP^＋ group compared with that in Control group. HPP induced a significant increase in cell viability and a marked decrease in population of apoptotic cells of the MPP^＋- treated PC 12 cells, accompanied with up-regulation of 14-3-3 protein and increase of ERK 1/2 and p38 MAPK activities. The 14-3-3 protein expression was positively correlated with the phosphorylation of ERK1/2. Furthermore, inhibition of the ERK1/2 with PD98059 abolished the 14-3-3 protein up-regulation in PC 12 cells induced by HPP. Conclusion HPP protects PC 12 cells against MPP＋ toxicity by up-regulating 14-3-3 protein expression through the ERK1/2 and p38 MAPK signaling pathways.

PI3K/AKT信号通路对冷却滩羊肉贮藏期间细胞凋亡的影响

以滩羊后腿肉为研究对象,采用10μmol/L磷脂酰肌醇3激酶(phosphoinositide 3-kinase,PI3K)抑制剂LY294002溶液对滩羊肉进行注射处理,4℃条件下分别贮藏0、2、4、6、8 d,通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和蛋白质免疫印迹分析PI3K、蛋白激酶B(protein kinase B,AKT)蛋白的表达情况,以此验证PI3K/AKT信号通路抑制的有效性,同时分析滩羊肉贮藏期间能量因子、氧化应激水平、线粒体损伤程度以及胱天蛋白酶(cysteine aspastic acid-specific protease,Caspase)-3活性的变化,以探索PI3K/AKT信号通路对冷却滩羊肉贮藏期间细胞凋亡途径的诱导机制。结果表明,PI3K和AKT蛋白表达量均减少,验证了PI3K/AKT信号通路被抑制的有效性。与对照组相比,LY294002处理组线粒体ATP、糖原含量、琥珀酸脱氢酶和柠檬酸合成酶活性显著下降(P<0.05);线粒体活性氧(reactive oxygen species,ROS)逐渐增多,氧化应激水平和线粒体膜通透性转换孔(mitochondrial permeability transition pore,MPTP)开放程度增加;膜电位显著下降(P<0.05);凋亡因子Caspase-3活性显著升高(P<0.05),表明PI3K/AKT信号通路通过促进ROS产生并与PI3K相互作用,介导了下游Caspase-3的活化,使线粒体结构与功能受损,导致MPTP开放、膜电位降低,进而诱发细胞凋亡。

外周血受体相互作用蛋白激酶3、混合系列蛋白激酶样结构域水平与新生儿坏死性小肠结肠炎病情严重程度的关系

目的分析新生儿坏死性小肠结肠炎(NEC)患儿外周血受体相互作用蛋白激酶3(RIPK3)、混合系列蛋白激酶样结构域(MLKL)的表达情况及其与病情严重程度的关系。方法选取92例NEC患儿纳入NEC组,并根据病情严重程度进一步分为轻度NEC组(Ⅰ级)60例和重度NEC组(Ⅱ~Ⅲ级)32例,另选取同期诊治的60例腹股沟斜疝患儿纳入对照组。采用实时荧光定量聚合酶链反应检测外周血RIPK3 mRNA、MLKL mRNA表达;采用Pearson相关分析法明确NEC组外周血RIPK3 mRNA与MLKL mRNA表达的相关性;采用免疫印迹法检测NEC回肠组织和正常回肠组织中RIPK3、MLKL蛋白表达;采用多因素Logistic回归分析明确重度NEC发生的独立危险因素。绘制受试者工作特征曲线,分析外周血RIPK3 mRNA、MLKL mRNA单独及联合预测重度NEC的价值。结果NEC组外周血RIPK3 mRNA、MLKL mRNA相对表达量分别为(2.41±0.52)、(3.03±0.64),高于对照组的(1.02±0.21)、(0.93±0.20),差异有统计学意义(P<0.001)。NEC回肠组织中RIPK3、MLKL蛋白相对灰度值分别为(1.20±0.21)、(1.13±0.24),高于正常回肠组织的(0.34±0.12)、(0.32±0.11),差异有统计学意义(P<0.05)。NEC组患儿外周血RIPK3 mRNA与MLKL mRNA相对表达量呈正相关(r=0.623,P<0.001)。重度NEC组合并气腹征、多器官功能障碍综合征、败血症者占比和RIPK3 mRNA、MLKL mRNA相对表达量均高于轻度NEC组,差异有统计学意义(P<0.05);RIPK3 mRNA、MLKL mRNA相对表达量升高是重度NEC发生的独立危险因素(P<0.05)。外周血RIPK3 mRNA、MLKL mRNA联合预测重度NEC的曲线下面积大于RIPK3 mRNA、MLKL mRNA单独预测(Z=4.127、4.261,P<0.05)。结论RIPK3 mRNA、MLKL mRNA在NEC患儿外周血中表达升高,两者均与NEC病情严重程度有关,且两者联合检测对重度NEC具有较高的预测价值。