In this paper,the biological function of PLK-1,the correlation between PLK-1 and tumors,and the latest research progress on PLK-1 inhibitors under study are reviewed,in order to provide references for the research and...In this paper,the biological function of PLK-1,the correlation between PLK-1 and tumors,and the latest research progress on PLK-1 inhibitors under study are reviewed,in order to provide references for the research and development of PLK-1 inhibitors.展开更多
Invasive breast carcinoma(BRCA)is associated with poor prognosis and high risk of mortality.Therefore,it is critical to identify novel biomarkers for the prognostic assessment of BRCA.Methods:The expression data of po...Invasive breast carcinoma(BRCA)is associated with poor prognosis and high risk of mortality.Therefore,it is critical to identify novel biomarkers for the prognostic assessment of BRCA.Methods:The expression data of polo-like kinase 1(PLK1)in BRCA and the corresponding clinical information were extracted from TCGA and GEO databases.PLK1 expression was validated in diverse breast cancer cell lines by quantitative real-time polymerase chain reaction(qRT-PCR)and western blotting.Single sample gene set enrichment analysis(ssGSEA)was performed to evaluate immune infiltration in the BRCA microenvironment,and the random forest(RF)and support vector machine(SVM)algorithms were used to screen for the hub infiltrating cells and calculate the immunophenoscore(IPS).The RF algorithm and COX regression model were applied to calculate survival risk scores based on the PLK1 expression and immune cell infiltration.Finally,a prognostic nomogram was constructed with the risk score and pathological stage,and its clinical potential was evaluated by plotting calibration charts and DCA curves.The application of the nomogram was further validated in an immunotherapy cohort.Results:PLK1 expression was significantly higher in the tumor samples in TCGA-BRCA cohort.Furthermore,PLK1 expression level,age and stage were identified as independent prognostic factors of BRCA.While the IPS was unaffected by PLK1 expression,the TMB and MATH scores were higher in the PLK1-high group,and the TIDE scores were higher for the PLK1-low patients.We also identified 6 immune cell types with high infiltration,along with 11 immune cell types with low infiltration in the PLK1-high tumors.A risk score was devised using PLK1 expression and hub immune cells,which predicted the prognosis of BRCA patients.In addition,a nomogram was constructed based on the risk score and pathological staging,and showed good predictive performance.Conclusions:PLK1 expression and immune cell infiltration can predict post-immunotherapy prognosis of BRCA patients.展开更多
BACKGROUND MicroRNAs(miRNAs)regulate gene expression and play a critical role in cancer physiology.However,there is still a limited understanding of the function and regulatory mechanism of miRNAs in gastric cancer(GC...BACKGROUND MicroRNAs(miRNAs)regulate gene expression and play a critical role in cancer physiology.However,there is still a limited understanding of the function and regulatory mechanism of miRNAs in gastric cancer(GC).AIM To investigate the role and molecular mechanism of miRNA-145-5p(miR145-5p)in the progression of GC.METHODS Real-time polymerase chain reaction(RT-PCR)was used to detect miRNA expression in human GC tissues and cells.The ability of cancer cells to migrate and invade was assessed using wound-healing and transwell assays,respectively.Cell proliferation was measured using cell counting kit-8 and colony formation assays,and apoptosis was evaluated using flow cytometry.Expression of the epithelial-mesenchymal transition(EMT)-associated protein was determined by Western blot.Targets of miR-145-5p were predicated using bioinformatics analysis and verified using a dual-luciferase reporter system.Serpin family E member 1(SERPINE1)expression in GC tissues and cells was evaluated using RT-PCR and immunohistochemical staining.The correlation between SERPINE1 expression and overall patient survival was determined using Kaplan-Meier plot analysis.The association between SERPINE1 and GC progression was also tested.A rescue experiment of SERPINE1 overexpression was conducted to verify the relationship between this protein and miR-145-5p.The mechanism by which miR-145-5p influences GC progression was further explored by assessing tumor formation in nude mice.RESULTS GC tissues and cells had reduced miR-145-5p expression and SERPINE1 was identified as a direct target of this miRNA.Overexpression of miR-145-5p was associated with decreased GC cell proliferation,invasion,migration,and EMT,and these effects were reversed by forcing SERPINE1 expression.Kaplan-Meier plot analysis revealed that patients with higher SERPINE1 expression had a shorter survival rate than those with lower SERPINE1 expression.Nude mouse tumorigenesis experiments confirmed that miR-145-5p targets SERPINE1 to regulate extracellular signal-regulated kinase-1/2(ERK1/2).CONCLUSION This study found that miR-145-5p inhibits tumor progression and is expressed in lower amounts in patients with GC.MiR-145-5p was found to affect GC cell proliferation,migration,and invasion by negatively regulating SERPINE1 levels and controlling the ERK1/2 pathway.展开更多
In order to investigate the effect of Polo-like kinase-1 （Plk1） depletion on cell cycle progression and cell growth in lung cancer cells, a recombinant plasmid containing antisense RNA targeting Plk1 （pcDNA3-Plk1）...In order to investigate the effect of Polo-like kinase-1 （Plk1） depletion on cell cycle progression and cell growth in lung cancer cells, a recombinant plasmid containing antisense RNA targeting Plk1 （pcDNA3-Plk1） was transfected into A549 cells by lipofectine. RT-PCR and Western-blot were used to detect the Plk1 gene expression. Cell proliferation was evaluated by direct cell counting and bromodeoxyuridine （BrdU） labeling. Cell cycle distribution and apoptosis were examined by flow cytometry, and the inhibition rate （IR） by vinorebline （NVB） was determined by MTF assay. The results showed that after transfection of pcDNA3-Plk1 into A549 cells, the expression levels of Plk1 mRNA and protein were greatly decreased. In pcDNA3-Plk1 transfected groups, abnormal morphological changes of cells and growth inhibition were observed, and the BrdU labeling index was significantly lower than in the control groups （P〈0.05）. Cells in pcDNA3-Plk1 transfected groups were arresed in G2/M phase and apoptosis was detectable 72 h post transfection. IR induced by vinorebline in pcDNA3-Plk1 transfected groups was significantly higher than in other groups. These data suggested that antisense RNA targeting Plk1 could suppress the Plk1 expression, and therefore, significantly inhibit cell proliferation and induce cell cycle arrest and apoptosis. Moreover, it sensitized lung cancer cells to chemotherapy.展开更多
BACKGROUND Hepatocellular carcinoma(HCC),often diagnosed at advanced stages without curative therapies,is the fifth most common malignant cancer and the second leading cause of cancer-related mortality.Polo-like kinas...BACKGROUND Hepatocellular carcinoma(HCC),often diagnosed at advanced stages without curative therapies,is the fifth most common malignant cancer and the second leading cause of cancer-related mortality.Polo-like kinase 1(PLK1)is activated in the late G2 phase of the cell cycle and is required for entry to mitosis.Interestingly,PLK1 is overexpressed in many HCC patients and is highly associated with poor clinical outcome.Baculoviral inhibitor of apoptosis repeatcontaining 5(BIRC5)is also highly overexpressed in HCC and plays key roles in this malignancy.AIM To determine the expression patterns of PLK1 and BIRC5,as well as their correlation with p53 mutation status and patient clinical outcome.METHODS The expression patterns of PLK1 and BIRC5,and their correlation with p53 mutation status or patient clinical outcome were analyzed using a TCGA HCC dataset.Cell viability,cell apoptosis,and cell cycle arrest assays were conducted to investigate the efficacy of the PLK1 inhibitors volasertib and GSK461364 and the BIRC5 inhibitor YM155,alone or in combination.The in vivo efficacy of volasertib and YM155,alone or in combination,was assessed in p53-mutated Huh7-derived xenograft models in immune-deficient NSIG mice.RESULTS Our bioinformatics analysis using a TCGA HCC dataset revealed that PLK1 and BIRC5 were overexpressed in the same patient subset and their expression was highly correlated.The overexpression of both PLK1 and BIRC5 was more frequently detected in HCC with p53 mutations.High PLK1 or BIRC5 expression significantly correlated with poor clinical outcome.PLK1 inhibitors(volasertib and GSK461364)or a BIRC5 inhibitor(YM155)selectively targeted Huh7 cells with mutated p53,but not HepG2 cells with wild-type p53.The combination treatment of volasertib and YM155 synergistically inhibited the viability of Huh7 cells via apoptotic pathway.The efficacy of volasertib and YM155,alone or in combination,was validated in vivo in a Huh7-derived xenograft model.CONCLUSION PLK1 and BIRC5 are highly co-expressed in p53-mutated HCC and inhibition of both PLK1 and BIRC5 synergistically compromises the viability of p53-mutated HCC cells in vitro and in vivo.展开更多
BACKGROUND Epidemiological studies have revealed a correlation between Alzheimer’s disease(AD)and type 2 diabetes mellitus(T2D).Insulin resistance in the brain is a common feature in patients with T2D and AD.KAT7 is ...BACKGROUND Epidemiological studies have revealed a correlation between Alzheimer’s disease(AD)and type 2 diabetes mellitus(T2D).Insulin resistance in the brain is a common feature in patients with T2D and AD.KAT7 is a histone acetyltransferase that participates in the modulation of various genes.AIM To determine the effects of KAT7 on insulin patients with AD.METHODS APPswe/PS1-dE9 double-transgenic and db/db mice were used to mimic AD and diabetes,respectively.An in vitro model of AD was established by Aβstimulation.Insulin resistance was induced by chronic stimulation with high insulin levels.The expression of microtubule-associated protein 2(MAP2)was assessed using immunofluorescence.The protein levels of MAP2,Aβ,dual-specificity tyrosine phosphorylation-regulated kinase-1A(DYRK1A),IRS-1,p-AKT,total AKT,p-GSK3β,total GSK3β,DYRK1A,and KAT7 were measured via western blotting.Accumulation of reactive oxygen species(ROS),malondialdehyde(MDA),and SOD activity was measured to determine cellular oxidative stress.Flow cytometry and CCK-8 assay were performed to evaluate neuronal cell death and proliferation,respectively.Relative RNA levels of KAT7 and DYRK1A were examined using quantitative PCR.A chromatin immunoprecipitation assay was conducted to detect H3K14ac in DYRK1A.RESULTS KAT7 expression was suppressed in the AD mice.Overexpression of KAT7 decreased Aβaccumulation and MAP2 expression in AD brains.KAT7 overexpression decreased ROS and MDA levels,elevated SOD activity in brain tissues and neurons,and simultaneously suppressed neuronal apoptosis.KAT7 upregulated levels of p-AKT and p-GSK3βto alleviate insulin resistance,along with elevated expression of DYRK1A.KAT7 depletion suppressed DYRK1A expression and impaired H3K14ac of DYRK1A.HMGN1 overexpression recovered DYRK1A levels and reversed insulin resistance caused by KAT7 depletion.CONCLUSION We determined that KAT7 overexpression recovered insulin sensitivity in AD by recruiting HMGN1 to enhance DYRK1A acetylation.Our findings suggest that KAT7 is a novel and promising therapeutic target for the resistance in AD.展开更多
1-methyl-4-phenylpyridinium ion （MPP^＋） induces endoplasmic reticulum stress and activates caspase-12 in PC12 cells, leading to neuronal apoptosis. However, the underlying molecular mechanism remains unknown. The p...1-methyl-4-phenylpyridinium ion （MPP^＋） induces endoplasmic reticulum stress and activates caspase-12 in PC12 cells, leading to neuronal apoptosis. However, the underlying molecular mechanism remains unknown. The present study investigated the regulatory effects of nerve growth factor （Akt activator） and lithium chloride （glycogen synthase kinase-3β inhibitor） on the endoplasmic reticulum stress signaling pathway. The results revealed that MPP＋ induced expression of Bip and C/EBP homologous protein. The upregulation of Bip and C/EBP homologous protein, as well as the decreased pro-caspase-12 level induced by MPP^＋ were inhibited by pretreatment of the nerve growth factor or lithium chloride. These results suggest that the phosphatidylinositol 3 kinase-Aktglycogen synthase kinase-3β pathway is involved in MPP-induced endoplasmic reticulum stress.展开更多
Cerebral angiogenesis in the early stages after cerebral ischemia injury is essential for the recovery of nerve function,in which fetal liver kinase-1（Flk-1）,as a major regulator of vasculogenesis and angiogenesis,p...Cerebral angiogenesis in the early stages after cerebral ischemia injury is essential for the recovery of nerve function,in which fetal liver kinase-1（Flk-1）,as a major regulator of vasculogenesis and angiogenesis,plays a very important role.Microvessel density（MVD）was greater in an aged model group compared with the young sham operated group（P 〈 0.01）.MVD and the sum of the lumen area were decreased in the aged group at 1,3,6 and 12 days following ischemia/reperfusion（I/R）injury compared with the young model group（P 〈 0.05 and P 〈 0.01,respectively）.Flk-1 protein and mRNA expression was greater in the aged model group when compared with the young sham operated group（P 〈 0.01）.Flk-1 protein and mRNA expression was lower in the aged group at 1,3,6 and 12 days after I/R compared with the young model group（P 〈 0.01）.Flk-1 expression in aged rats attenuated rapidly,but was still maintained at relatively higher levels at 12 days following I/R in younger rats.The results suggest that angiogenesis was weakened after cerebral I/R in aged rats,and the mechanism of which might be correlated with attenuated expression of Flk-1 protein and mRNA.展开更多
This study was aimed to explore the role of stromal-derived factor 1 （SDF-1）/CXC chemokine receptor 4 （CXCR4） axis in mediating the metastasis of ovarian cancer cells through activation of extracellular signal-reg...This study was aimed to explore the role of stromal-derived factor 1 （SDF-1）/CXC chemokine receptor 4 （CXCR4） axis in mediating the metastasis of ovarian cancer cells through activation of extracellular signal-regulated kinase-1/2 （ERK-1/2） signaling pathway. A highly metastatic ovarian cancer cell line, SKOV3, was used in the study. Intracellular calcium mobilization was detected by using laser scanning confocal fluorescence microscopy. Western blotting was used to detect the phosphorylation of ERK1/2 in SDF-1α-treated SKOV3 cells. Adhesion capability and matrix metalloproteinase （MMP） activity of ovarian cancer cells after exposure to SDF-1 a were measured by adhesion assay and gelatin zymography. The results showed that SDF-1α induced rapid intracellular calcium mobilization in SKOV3 cells, as well as the phosphorylation of ERK-1/2. The adhesion of ovarian cancer cells to fibronectin and collagen Ⅳ was increased after SDF-1α treatment. An inhibitor of ERK-1/2 signaling, PD98059, could antagonize such effects of SDF-1α. SDF-1α could also increase the secretion of active MMP-2 and MMP-9. It was concluded that the SDF-1/CXCR4 axis played a critical role in the metastasis of human ovarian cancer by increasing the adhesion capability of cancer cells and the activity of MMP-2 and MMP-9 via ERK1/2 signaling pathway.展开更多
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 ribos...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.展开更多
文摘In this paper,the biological function of PLK-1,the correlation between PLK-1 and tumors,and the latest research progress on PLK-1 inhibitors under study are reviewed,in order to provide references for the research and development of PLK-1 inhibitors.
基金funded by the Natural Science Foundation of Higher Education Institutions of Auhui Province(Grant No.KJ2021A0352)the Research Fund Project of Anhui Medical University(Grant No.2020xkj236)Applied Medicine Research Project of Hefei Health Commission(Grant No.HWKJ2019-172-14).
文摘Invasive breast carcinoma(BRCA)is associated with poor prognosis and high risk of mortality.Therefore,it is critical to identify novel biomarkers for the prognostic assessment of BRCA.Methods:The expression data of polo-like kinase 1(PLK1)in BRCA and the corresponding clinical information were extracted from TCGA and GEO databases.PLK1 expression was validated in diverse breast cancer cell lines by quantitative real-time polymerase chain reaction(qRT-PCR)and western blotting.Single sample gene set enrichment analysis(ssGSEA)was performed to evaluate immune infiltration in the BRCA microenvironment,and the random forest(RF)and support vector machine(SVM)algorithms were used to screen for the hub infiltrating cells and calculate the immunophenoscore(IPS).The RF algorithm and COX regression model were applied to calculate survival risk scores based on the PLK1 expression and immune cell infiltration.Finally,a prognostic nomogram was constructed with the risk score and pathological stage,and its clinical potential was evaluated by plotting calibration charts and DCA curves.The application of the nomogram was further validated in an immunotherapy cohort.Results:PLK1 expression was significantly higher in the tumor samples in TCGA-BRCA cohort.Furthermore,PLK1 expression level,age and stage were identified as independent prognostic factors of BRCA.While the IPS was unaffected by PLK1 expression,the TMB and MATH scores were higher in the PLK1-high group,and the TIDE scores were higher for the PLK1-low patients.We also identified 6 immune cell types with high infiltration,along with 11 immune cell types with low infiltration in the PLK1-high tumors.A risk score was devised using PLK1 expression and hub immune cells,which predicted the prognosis of BRCA patients.In addition,a nomogram was constructed based on the risk score and pathological staging,and showed good predictive performance.Conclusions:PLK1 expression and immune cell infiltration can predict post-immunotherapy prognosis of BRCA patients.
文摘BACKGROUND MicroRNAs(miRNAs)regulate gene expression and play a critical role in cancer physiology.However,there is still a limited understanding of the function and regulatory mechanism of miRNAs in gastric cancer(GC).AIM To investigate the role and molecular mechanism of miRNA-145-5p(miR145-5p)in the progression of GC.METHODS Real-time polymerase chain reaction(RT-PCR)was used to detect miRNA expression in human GC tissues and cells.The ability of cancer cells to migrate and invade was assessed using wound-healing and transwell assays,respectively.Cell proliferation was measured using cell counting kit-8 and colony formation assays,and apoptosis was evaluated using flow cytometry.Expression of the epithelial-mesenchymal transition(EMT)-associated protein was determined by Western blot.Targets of miR-145-5p were predicated using bioinformatics analysis and verified using a dual-luciferase reporter system.Serpin family E member 1(SERPINE1)expression in GC tissues and cells was evaluated using RT-PCR and immunohistochemical staining.The correlation between SERPINE1 expression and overall patient survival was determined using Kaplan-Meier plot analysis.The association between SERPINE1 and GC progression was also tested.A rescue experiment of SERPINE1 overexpression was conducted to verify the relationship between this protein and miR-145-5p.The mechanism by which miR-145-5p influences GC progression was further explored by assessing tumor formation in nude mice.RESULTS GC tissues and cells had reduced miR-145-5p expression and SERPINE1 was identified as a direct target of this miRNA.Overexpression of miR-145-5p was associated with decreased GC cell proliferation,invasion,migration,and EMT,and these effects were reversed by forcing SERPINE1 expression.Kaplan-Meier plot analysis revealed that patients with higher SERPINE1 expression had a shorter survival rate than those with lower SERPINE1 expression.Nude mouse tumorigenesis experiments confirmed that miR-145-5p targets SERPINE1 to regulate extracellular signal-regulated kinase-1/2(ERK1/2).CONCLUSION This study found that miR-145-5p inhibits tumor progression and is expressed in lower amounts in patients with GC.MiR-145-5p was found to affect GC cell proliferation,migration,and invasion by negatively regulating SERPINE1 levels and controlling the ERK1/2 pathway.
文摘In order to investigate the effect of Polo-like kinase-1 （Plk1） depletion on cell cycle progression and cell growth in lung cancer cells, a recombinant plasmid containing antisense RNA targeting Plk1 （pcDNA3-Plk1） was transfected into A549 cells by lipofectine. RT-PCR and Western-blot were used to detect the Plk1 gene expression. Cell proliferation was evaluated by direct cell counting and bromodeoxyuridine （BrdU） labeling. Cell cycle distribution and apoptosis were examined by flow cytometry, and the inhibition rate （IR） by vinorebline （NVB） was determined by MTF assay. The results showed that after transfection of pcDNA3-Plk1 into A549 cells, the expression levels of Plk1 mRNA and protein were greatly decreased. In pcDNA3-Plk1 transfected groups, abnormal morphological changes of cells and growth inhibition were observed, and the BrdU labeling index was significantly lower than in the control groups （P〈0.05）. Cells in pcDNA3-Plk1 transfected groups were arresed in G2/M phase and apoptosis was detectable 72 h post transfection. IR induced by vinorebline in pcDNA3-Plk1 transfected groups was significantly higher than in other groups. These data suggested that antisense RNA targeting Plk1 could suppress the Plk1 expression, and therefore, significantly inhibit cell proliferation and induce cell cycle arrest and apoptosis. Moreover, it sensitized lung cancer cells to chemotherapy.
基金Supported by National Science and Technology Major Project,No.2018ZX10732-202-004Tianjin Science and Technology Plan Project,No.17JCYBJC26100 and No.19ZXDBSY00030.
文摘BACKGROUND Hepatocellular carcinoma(HCC),often diagnosed at advanced stages without curative therapies,is the fifth most common malignant cancer and the second leading cause of cancer-related mortality.Polo-like kinase 1(PLK1)is activated in the late G2 phase of the cell cycle and is required for entry to mitosis.Interestingly,PLK1 is overexpressed in many HCC patients and is highly associated with poor clinical outcome.Baculoviral inhibitor of apoptosis repeatcontaining 5(BIRC5)is also highly overexpressed in HCC and plays key roles in this malignancy.AIM To determine the expression patterns of PLK1 and BIRC5,as well as their correlation with p53 mutation status and patient clinical outcome.METHODS The expression patterns of PLK1 and BIRC5,and their correlation with p53 mutation status or patient clinical outcome were analyzed using a TCGA HCC dataset.Cell viability,cell apoptosis,and cell cycle arrest assays were conducted to investigate the efficacy of the PLK1 inhibitors volasertib and GSK461364 and the BIRC5 inhibitor YM155,alone or in combination.The in vivo efficacy of volasertib and YM155,alone or in combination,was assessed in p53-mutated Huh7-derived xenograft models in immune-deficient NSIG mice.RESULTS Our bioinformatics analysis using a TCGA HCC dataset revealed that PLK1 and BIRC5 were overexpressed in the same patient subset and their expression was highly correlated.The overexpression of both PLK1 and BIRC5 was more frequently detected in HCC with p53 mutations.High PLK1 or BIRC5 expression significantly correlated with poor clinical outcome.PLK1 inhibitors(volasertib and GSK461364)or a BIRC5 inhibitor(YM155)selectively targeted Huh7 cells with mutated p53,but not HepG2 cells with wild-type p53.The combination treatment of volasertib and YM155 synergistically inhibited the viability of Huh7 cells via apoptotic pathway.The efficacy of volasertib and YM155,alone or in combination,was validated in vivo in a Huh7-derived xenograft model.CONCLUSION PLK1 and BIRC5 are highly co-expressed in p53-mutated HCC and inhibition of both PLK1 and BIRC5 synergistically compromises the viability of p53-mutated HCC cells in vitro and in vivo.
基金Supported by Natural Science Foundation of Shandong Province,No.ZR2020MH147National Natural Science Foundation of China,No.82002343.
文摘BACKGROUND Epidemiological studies have revealed a correlation between Alzheimer’s disease(AD)and type 2 diabetes mellitus(T2D).Insulin resistance in the brain is a common feature in patients with T2D and AD.KAT7 is a histone acetyltransferase that participates in the modulation of various genes.AIM To determine the effects of KAT7 on insulin patients with AD.METHODS APPswe/PS1-dE9 double-transgenic and db/db mice were used to mimic AD and diabetes,respectively.An in vitro model of AD was established by Aβstimulation.Insulin resistance was induced by chronic stimulation with high insulin levels.The expression of microtubule-associated protein 2(MAP2)was assessed using immunofluorescence.The protein levels of MAP2,Aβ,dual-specificity tyrosine phosphorylation-regulated kinase-1A(DYRK1A),IRS-1,p-AKT,total AKT,p-GSK3β,total GSK3β,DYRK1A,and KAT7 were measured via western blotting.Accumulation of reactive oxygen species(ROS),malondialdehyde(MDA),and SOD activity was measured to determine cellular oxidative stress.Flow cytometry and CCK-8 assay were performed to evaluate neuronal cell death and proliferation,respectively.Relative RNA levels of KAT7 and DYRK1A were examined using quantitative PCR.A chromatin immunoprecipitation assay was conducted to detect H3K14ac in DYRK1A.RESULTS KAT7 expression was suppressed in the AD mice.Overexpression of KAT7 decreased Aβaccumulation and MAP2 expression in AD brains.KAT7 overexpression decreased ROS and MDA levels,elevated SOD activity in brain tissues and neurons,and simultaneously suppressed neuronal apoptosis.KAT7 upregulated levels of p-AKT and p-GSK3βto alleviate insulin resistance,along with elevated expression of DYRK1A.KAT7 depletion suppressed DYRK1A expression and impaired H3K14ac of DYRK1A.HMGN1 overexpression recovered DYRK1A levels and reversed insulin resistance caused by KAT7 depletion.CONCLUSION We determined that KAT7 overexpression recovered insulin sensitivity in AD by recruiting HMGN1 to enhance DYRK1A acetylation.Our findings suggest that KAT7 is a novel and promising therapeutic target for the resistance in AD.
基金the National Natural Science Foundation of China, No. 30860085a grant from the Candidates of Young and Middle-Aged Academic Leaders of Yunnan Province, No. 2006PY01-07the Natural Science Foundation of Yunnan Province, No. 2007C177M
文摘1-methyl-4-phenylpyridinium ion （MPP^＋） induces endoplasmic reticulum stress and activates caspase-12 in PC12 cells, leading to neuronal apoptosis. However, the underlying molecular mechanism remains unknown. The present study investigated the regulatory effects of nerve growth factor （Akt activator） and lithium chloride （glycogen synthase kinase-3β inhibitor） on the endoplasmic reticulum stress signaling pathway. The results revealed that MPP＋ induced expression of Bip and C/EBP homologous protein. The upregulation of Bip and C/EBP homologous protein, as well as the decreased pro-caspase-12 level induced by MPP^＋ were inhibited by pretreatment of the nerve growth factor or lithium chloride. These results suggest that the phosphatidylinositol 3 kinase-Aktglycogen synthase kinase-3β pathway is involved in MPP-induced endoplasmic reticulum stress.
基金the National Natural Science Foundation of China, No. 30371812the Henan Provincial Science Fund for Distinguished Young Scholars, No. 0612000700
文摘Cerebral angiogenesis in the early stages after cerebral ischemia injury is essential for the recovery of nerve function,in which fetal liver kinase-1（Flk-1）,as a major regulator of vasculogenesis and angiogenesis,plays a very important role.Microvessel density（MVD）was greater in an aged model group compared with the young sham operated group（P 〈 0.01）.MVD and the sum of the lumen area were decreased in the aged group at 1,3,6 and 12 days following ischemia/reperfusion（I/R）injury compared with the young model group（P 〈 0.05 and P 〈 0.01,respectively）.Flk-1 protein and mRNA expression was greater in the aged model group when compared with the young sham operated group（P 〈 0.01）.Flk-1 protein and mRNA expression was lower in the aged group at 1,3,6 and 12 days after I/R compared with the young model group（P 〈 0.01）.Flk-1 expression in aged rats attenuated rapidly,but was still maintained at relatively higher levels at 12 days following I/R in younger rats.The results suggest that angiogenesis was weakened after cerebral I/R in aged rats,and the mechanism of which might be correlated with attenuated expression of Flk-1 protein and mRNA.
基金supported by a grant from Health Bureau of Hubei province (No. JX1A07)
文摘This study was aimed to explore the role of stromal-derived factor 1 （SDF-1）/CXC chemokine receptor 4 （CXCR4） axis in mediating the metastasis of ovarian cancer cells through activation of extracellular signal-regulated kinase-1/2 （ERK-1/2） signaling pathway. A highly metastatic ovarian cancer cell line, SKOV3, was used in the study. Intracellular calcium mobilization was detected by using laser scanning confocal fluorescence microscopy. Western blotting was used to detect the phosphorylation of ERK1/2 in SDF-1α-treated SKOV3 cells. Adhesion capability and matrix metalloproteinase （MMP） activity of ovarian cancer cells after exposure to SDF-1 a were measured by adhesion assay and gelatin zymography. The results showed that SDF-1α induced rapid intracellular calcium mobilization in SKOV3 cells, as well as the phosphorylation of ERK-1/2. The adhesion of ovarian cancer cells to fibronectin and collagen Ⅳ was increased after SDF-1α treatment. An inhibitor of ERK-1/2 signaling, PD98059, could antagonize such effects of SDF-1α. SDF-1α could also increase the secretion of active MMP-2 and MMP-9. It was concluded that the SDF-1/CXCR4 axis played a critical role in the metastasis of human ovarian cancer by increasing the adhesion capability of cancer cells and the activity of MMP-2 and MMP-9 via ERK1/2 signaling pathway.
基金Supported by National Research Foundation of Korea grant funded by the Korea Government (MEST),No.2010-0001356Supported by a grant from the National R and D Program for Cancer Control funded by Ministry of Health and Welfare,Republic of Korea,No.0720560
文摘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.
