Despite the continuous developments and advancements in the treatment of gastric cancer(GC),which is one of the most prevalent types of cancer in China,the overall survival is still poor for most patients with advance...Despite the continuous developments and advancements in the treatment of gastric cancer(GC),which is one of the most prevalent types of cancer in China,the overall survival is still poor for most patients with advanced GC.In recent years,with the progress in tumor immunology research,attention has shifted toward immunotherapy as a therapeutic approach for GC.Programmed cell death protein 1(PD-1)inhibitors,as novel immunosuppressive medications,have been widely utilized in the treatment of GC.However,many patients are still resistant to PD-1 inhibitors and experience recurrence in the advanced stages of PD-1 immunotherapy.To reduce the occurrence of drug resistance and recurrence in GC patients receiving PD-1 immunotherapy,to maximize the clinical activity of immunosuppressive drugs,and to elicit a lasting immune response,it is essential to research the tumor microenvironment mechanisms leading to PD-1 inhibitor resistance in GC patients.This article reviews the progress in studying the factors influencing the resistance to PD-1 inhibitors in the GC tumor microenvironment,aiming to provide insights and a basis for reducing resistance to PD-1 inhibitors for GC patients in the future.展开更多
AIM： To reverse the multidrug resistance （MDR） by RNA interference （RNAi）-mediated MDRI suppression in heparoma cells.METHODS： For reversing MDR by RNAi technology, two different short hairpin RNAs （shRNAs） we...AIM： To reverse the multidrug resistance （MDR） by RNA interference （RNAi）-mediated MDRI suppression in heparoma cells.METHODS： For reversing MDR by RNAi technology, two different short hairpin RNAs （shRNAs） were designed and constructed into pGenSil-1 plasmid, respectively. They were then transfected into a highly adriarnycin-resistant HepG2 hepatorna cell line （HepG2/ADM）. The RNAi effect on MDR was evaluated by real-time PCR, cell cytotoxicity assay and rhodarnine 123 （Rh123） efflux assy. RESULTS： The stably-transfected clones showed various degrees of reversal of MDR phenotype. Surprisingly, the MDR phenotype was completely reversed in two transfected clones. CONCLUSION： MDR can be reversed by the shRNAmediated MDRI suppression in HepG2/ADM cells, which provides a valuable clue to make multidrug-resistant hepatoma cells sensitive to anti-cancer drugs.展开更多
Multidrug resistance（MDR） plays a major obstacle to successful gastric cancer chemotherapy.The purpose of this study was to investigate the MDR reversal effect and mechanisms of hyperthermia in combination with nefe...Multidrug resistance（MDR） plays a major obstacle to successful gastric cancer chemotherapy.The purpose of this study was to investigate the MDR reversal effect and mechanisms of hyperthermia in combination with neferine（Nef） in adriamycin（ADM） resistant human SGC7901/ADM gastric cancer cells.The MDR cells were heated at 42℃ and 45℃ for 30 min alone or combined with 10 μg/mL Nef.The cytotoxic effect of ADM was evaluated by MTT assay.Cellular plasma membrane lipid fluidity was detected by fluorescence polarization technique.Intracellular accumulation of ADM was monitored with high performance liquid chromatography.Mdr-1 mRNA,P-glycoprotein（P-gp）,γH2AX expression and γH2AX foci formation were determined by real-time PCR,Western blot and immunocytochemical staining respectively.It was found that different heating methods induced different cytotoxic effects.Water submerged hyperthermia had the strongest cytotoxicity of ADM and Nef combined with hyperthermia had a synergistic cytotoxicity of ADM in the MDR cells.The water submerged hyperthermia increased the cell membrane fluidity.Both water submerged hyperthermia and Nef increased the intracellular accumulation of ADM.The water submerged hyperthermia and Nef down-regulated the expression of mdr-1 mRNA and P-gp.The water submerged hyperthermia could damage DNA and increase the γH2AX expression of SGC7901/ADM cells.The higher temperature was,the worse effect was.Our results show that combined treatment of hyperthermia with Nef can synergistically reverse MDR in human SGC7901/ADM gastric cancer cells.展开更多
The brush border membrane vesicles (BBMVs) in midgut of Helicoverpa armigera weresuccessfully separated, and most of the Aminopeptidase N (APN) activities in BBMV werepreserved. The 3-[(3-chlor-amidopropyl) dimethylam...The brush border membrane vesicles (BBMVs) in midgut of Helicoverpa armigera weresuccessfully separated, and most of the Aminopeptidase N (APN) activities in BBMV werepreserved. The 3-[(3-chlor-amidopropyl) dimethylammonio]-1-propane-sulphonate (CHAPS)can enhance the dissolution of BBMV, and phosphatidylinositol-specific phosopholipase C(PI-PLC) can cleave the APN from midgut membrane. The APN was primarily purified usinga Mono-Q column. The results of immunoblotting showed that the 120 and 170kDa proteinsin the BBMV could bind Cry1Ac, and 120kDa APN was a glycosylphosphalidylinositol(GPI)-anchored protein. Two Bt-resistant strains (Bt-P, Bt-M) were obtained after beingselected for more than five years in laboratory using Bt insecticides and Bt transgeniccotton incorporated into diet separately. The resistance of Bt-P and Bt-M were 1083.3and 48.7 times that of susceptible strain. The genes encoding APN1 in midgut ofsusceptible and resistant H.armigera were cloned by PCR and RACE techniques. Theinferred amino acid sequences of APN1 possessed the common character of APN family ininsects. In comparison with APN1 in susceptible strain, three nucleotide mutations wereobserved in the APN1 of Bt-M strain and resulted in two amino acid replace in theputative protein sequences, and eight nucleotide mutations were observed in Bt-P strainand resulted in five amino acid replace.展开更多
AIM：To investigate the altering expression profiles of efflux transporters such as breast cancer-resistance protein（BCRP）,lung resistance protein（LRP）,and multidrug resistance protein 1（MDR1） at the inner blood...AIM：To investigate the altering expression profiles of efflux transporters such as breast cancer-resistance protein（BCRP）,lung resistance protein（LRP）,and multidrug resistance protein 1（MDR1） at the inner blood-retinal barrier（BRB） during the development of early diabetic retinopathy（DR） and/or aging in mice.METHODS：Relative m RNA and protein expression profiles of these three efflux transporters in the retina during the development of early DR and/or aging in mice were examined.The differing expression profiles of Zonula occludens 1（ ZO-1） and vascular endothelial growth factor-A（ VEGFA） in the retina as well as the perfusion characterization of fluorescein isothiocyanate（FITC）-dextran and Evans blue were examined to evaluate the integrity of the inner BRB.RESULTS：There were significant alterations in these three efflux transporters＇ expression profiles in the m RNA and protein levels of the retina during the development of diabetes mellitus and/or aging.The development of early DR was confirmed by the expression profiles of ZO-1 and VEGFA in the retina as well as the compromised integrity of the inner BRB.CONCLUSION：The expression profiles of some efflux transporters such as BCRP,LRP,and MDR1 in mice retina during diabetic and/or aging conditions are tested,and the attenuated expression of BCRP,LRP,and MDR1 along with the breakdown of the inner BRB is found,which may be linked to the pathogenesis of early DR.展开更多
BACKGROUND:Sulfonylurea receptor 1(SUR1)and multidrug resistance protein 1(MRP1)are two prominent members of multidrug resistance proteins associated with insulin secretion. The aims of this study were to investigate ...BACKGROUND:Sulfonylurea receptor 1(SUR1)and multidrug resistance protein 1(MRP1)are two prominent members of multidrug resistance proteins associated with insulin secretion. The aims of this study were to investigate their expression in insulinomas and their sole and synergistic effects in modulating abnormal insulin secretion. METHODS:Fasting glucose,insulin and C-peptide were measured in 11 insulinoma patients and 11 healthy controls. Prolonged oral glucose tolerance tests were performed in 6 insulinoma patients.Insulin content,SUR1 and MRP1 were detected in 11 insulinoma patients by immunohistochemistry. SUR1 and MRP1 were also detected in 6 insulinoma patients by immunofluorescence. RESULTS:Insulinoma patients presented the typical demons-trations of Whipple’s triad.Fasting glucose of each insulinoma patient was lower than 2.8 mmol/L,and simultaneous insulin and C-peptide were increased in insulinoma patients. Prolonged oral glucose tolerance tests showed that insulin secretion in insulinoma patients were also stimulated by high glucose.Immunohistochemistry and immunofluorescence staining showed that SUR1 increased,but MRP1 decreased in insulinoma compared with the adjacent islets. CONCLUSIONS:The hypersecretion of insulin in insulinomas might be,at least partially,due to the enrichment of SUR1. In contrast,MRP1,which is down-regulated in insulinomas, might reflect a negative feedback in insulin secretion.展开更多
Introduction:Siva-1,as a pro-apoptotic protein,has been shown to induce extensive apoptosis in a number of different cell lines.In our previous study,we showed that overexpressed Siva-1 decreased the apoptosis of gast...Introduction:Siva-1,as a pro-apoptotic protein,has been shown to induce extensive apoptosis in a number of different cell lines.In our previous study,we showed that overexpressed Siva-1 decreased the apoptosis of gastric cancer cells.So,we believe that it can also work as an anti-apoptotic protein.The present study aimed to determine the specific role of Siva-1 in anticancer drug resistance in gastric cancer in vivo and in vitro and preliminarily reveal the mechanism.Materials and Methods:A vincristine-resistant MKN-28/VCR gastric cancer cell line with stably downregulated Siva-1 was established.The effect of Siva-1 downregulation on chemotherapeutic drug resistance was assessed by measuring the IC50 and pump rate of doxorubicin.Proliferation,apoptosis of cells,and cell cycle were detected via colony formation assay andflow cytometry,respectively.Additionally,migration and invasion of cells was detected via wound healing and transwell assays.Moreover,we determined in vivo effects of LV-Siva-1-RNAi on tumor size,and apoptotic cells in tumor tissues were detected using TUNEL and hematoxylin and eosin staining.Results:Siva-1 downregulation reduced the pump rate of doxorubicin and enhanced the response to drug treatment.Siva-1 negatively regulated proliferation and promoted apoptosis of cells by potentiality G2-M phase arresting.Inhibition of Siva-1 expression in MKN-28/VCR cells significantly weakened wound healing ability and decreased invasion ability.Poly(C)-binding protein 1(PCBP1)was identified as a Siva-1-interacting protein in yeast two-hybrid screening.Semiquantitative RT-PCR and western blotting revealed that Siva-1 downregulation could inhibit expression of PCBP1,Akt,and NF-κB and eventually decrease the expression of MDR1 and MRP1.Conclusion:The current study demonstrated that the downregulation of Siva-1,which functions as a regulator of MDR1 and MRP1 gene expression in gastric cancer cells by inhibiting PCBP1/Akt/NF-κB signaling pathway expression,enhanced the sensitivity of gastric cancer cells to certain chemotherapies.展开更多
BACKGROUND： Studies have shown that scorpion venom heat-resistant protein （SVHRP） exhibits protective effects on primary cultured hippocampal neurons. OBJECTIVE： To determine the effects of SVHRP on astrocyte acti...BACKGROUND： Studies have shown that scorpion venom heat-resistant protein （SVHRP） exhibits protective effects on primary cultured hippocampal neurons. OBJECTIVE： To determine the effects of SVHRP on astrocyte activity and synaptic density in the hippocampus induced by amyloid β peptide 1-40 （Aβ1-40） neurotoxicity. DESIGN, TIME AND SETTING： The randomized, controlled, animal experiment was performed at the Central Laboratory, the Laboratory of Human Anatomy, and the Laboratory of Physiology, in Dalian Medical University between March 2006 and June 2008. MATERIALS： Aβ1-40 was provided by Biosource, USA; SVHRP was a patented biological product of Dalian Medical University （No. ZL01 1 06166.9）. METHODS： A total of 27 healthy, 2-month-old, male SD rats were randomly assigned to 3 groups： control, Aβ, and SVHRP, with 9 rats in each group. Alzheimer＇s disease was simulated with 10 μg Aβ1-40 bilaterally injected into the hippocampus of the Aβ and SVHRP groups. The control group was injected with 2 μL 0.05% trifluoroacetic acid. One day following model establishment, the SVHRP group received an intraperitoneal injection of 2 μg/100 g SVHRP, while the control group and Aβ group received 0.5 mL/100 g tri-distilled water, once per day, for 10 consecutive days. MAIN OUTCOME MEASURES： At 16 days following model establishment, synaptophysin （p38） expression in CA1-CA4 regions of the rat hippocampus was determined by immunohistochemistry. Glial fibrillary acidic protein （GFAP） expression surrounding the hippocampal Aβ1-40 injected area was also detected. At 11 days following model establishment, escape latency, swimming time, and distance to target quadrant were measured using the Morris water maze. RESULTS： Compared with the control group, the Aβ group exhibited notably reduced p38 expression （P 〈 0.05） and notably increased GFAP expression in the rat hippocampus （P 〈 0.05）. Water maze results demonstrated that escape latency was prolonged （P 〈 0.05）, and swimming time and distance to the target quadrant were shortened in the Aβ group. Compared with the Aβ group, the SVHRP group exhibited notably increased p38 expression （P 〈 0.05） and notably decreased GFAP expression in the rat hippocampus （P 〈 0.05）. Water maze results demonstrated that escape latency was significantly reduced （P 〈 0.05）, and swimming time and distance to the target quadrant were significantly prolonged. CONCLUSION： SVHRP inhibited exogenous Aβ1-40-induced astrocyte activation and synaptic density decline in the rat hippocampus. Place navigation and spatial searching results showed that SVHRP blocked Aβ1-40-induced impaired learning and memory.展开更多
Obesity-induced type 2 diabetes is mainly due to excessive free fatty acids leading to insulin resistance.Increasing thermogenesis is regarded as an effective strategy for hypolipidemia and hypoglycemia.Ginsenoside is...Obesity-induced type 2 diabetes is mainly due to excessive free fatty acids leading to insulin resistance.Increasing thermogenesis is regarded as an effective strategy for hypolipidemia and hypoglycemia.Ginsenoside is a natural active component in Panax ginseng C.A.Meyer,and some of them enhance thermogenesis.However,there are few studies on the mechanism and target of ginsenosides enhancing thermogenesis.Using thermogenic protein uncoupling protein 1(UCP1)-luciferase reporter assay,we identifi ed ginsenoside F1 as a novel UCP1 activator in the ginsenosides library.Using pull down assay and inhibitor interference,we found F1 binds toβ3-adrenergic receptors(β3-AR)to enhance UCP1 expression via cAMP/PKA/CREB pathway.We also investigated the ability of F1 on energy metabolism in obesity-induced diabetic mice,including body weight,body composition and energy expenditure.The results of proteomics showed that F1 signifi cantly up-regulated thermogenesis proteins and lipolytic proteins,but down-regulated fatty acid synthesis proteins.Ginsenoside F1 increased thermogenesis and ameliorated insulin resistance specifi cally by promoting the browning of white adipose tissue in obese mice.Additionally,ginsenoside F1 improves norepinephrine-induced insulin resistance in adipocytes and hepatocytes,and shows a stronger mitochondria respiration ability than norepinephrine.These fi ndings suggest that ginsenoside F1 is a promising lead compound in the improvement of insulin resistance.展开更多
BACKGROUND Breast cancer(BC) remains a public health problem. Tamoxifen(TAM) resistance has caused great difficulties for treatment of BC patients. Eukaryotic translation initiation factor 4E binding protein 1(EIF4EBP...BACKGROUND Breast cancer(BC) remains a public health problem. Tamoxifen(TAM) resistance has caused great difficulties for treatment of BC patients. Eukaryotic translation initiation factor 4E binding protein 1(EIF4EBP1) plays critical roles in the tumorigenesis and progression of BC. However, the expression and mechanism of EIF4EBP1 in determining the efficacy of TAM therapy in BC patients are still unclear.AIM To investigate the expression and functions of EIF4EBP1 in determining the efficacy of TAM therapy in BC patients.METHODS High-throughput sequencing data of breast tumors were downloaded from the Gene Expression Omnibus database. Differential gene expression analysis identified EIF4EBP1 to be significantly upregulated in cancer tissues. Its prognostic value was analyzed. The biological function and related pathways of EIF4EBP1 was analyzed. Subsequently, the expression of EIF4EBP1 was determined by real-time reverse transcription polymerase chain reaction and western blotting. Cell Counting Kit-8 assays, colony formation assay and wound healing assay were used to understand the phenotypes of function of EIF4EBP1.RESULTS EIF4EBP1 was upregulated in the TAM-resistant cells, and EIF4EBP1 was related to the prognosis of BC patients. Gene Set Enrichment Analysis showed that EIF4EBP1 might be involved in Hedgehog signaling pathways. Decreasing the expression of EIF4EBP1 could reverse TAM resistance, whereas overexpression of EIF4EBP1 promoted TAM resistance.CONCLUSION This study indicated that EIF4EBP1 was overexpressed in the BC and TAM-resistant cell line, which increased cell proliferation, invasion, migration and TAM resistance in BC cells.展开更多
AIM:To clarify the specific roles and mechanisms of long interspersed nuclear element-1 ORF-1 protein [human long interspersed nuclear element-1(LINE-1),ORF-1p] in chemotherapeutic drug resistance and cell proliferati...AIM:To clarify the specific roles and mechanisms of long interspersed nuclear element-1 ORF-1 protein [human long interspersed nuclear element-1(LINE-1),ORF-1p] in chemotherapeutic drug resistance and cell proliferation regulation in hepatocellular carcinoma(HCC) cells.METHODS:MTT assays were performed to identify the effect of the chemotherapeutic drug toxicity on HepG2 cells.Cell proliferation inhibition and the IC 50 were calculated by the Origin 8.0 software.Western blotting assays were performed to investigate whether LINE-1 ORF-1p modulates the expression of some important genes,including p53,p27,p15,Bcl-2,mdr,and p-gp.To corroborate the proliferation and anchor-independent growth results,the HepG2 cells were analyzed by flow cytometry to investigate the effect of LINE-1 ORF1p on the apoptosis regulation.RESULTS:LINE-1 ORF-1p contributed to the resistance to several chemotherapeutic drugs(cisplatin and epirubicin) in HepG2 cells.The IC 50 of the epirubicin and cisplatin increased from 36.04 nmol/L to 59.11 nmol/L or from 37.94 nmol/L to 119.32 nmol/L.Repression of LINE-1 ORF-1p expression by the siRNA could markedly enhance the response of HepG2 cells to the epirubicin and cisplatin.The IC 50 correspondingly decreased from 28.06 nmol/L to 3.83 nmol/L or from 32.04 nmol/L to 2.89 nmol/L.Interestingly,down-regulation of LINE-1 ORF-1p level by siRNA could promote the response of HepG2 cells to the paclitaxel.The IC 50 decreased from 35.90 nmol/L to 7.36 nmol/L.However,overexpression of LINE-1 ORF-1p did not modulate the paclitaxel toxicity in HepG2 cells.Further Western blotting revealed that LINE-1 ORF-1p enhanced mdr and p-gp gene expression.As a protein arrested in the nucleus,LINE-1 ORF-1p may function through modulating transcriptional activity of some important transcription factors.Indeed,LINE-1 ORF-1p promoted HepG2 cell proliferation,anchor-independent growth and protected the cells against apoptosis through modulating the expression of p15,p21,p53,and Bcl-2 genes.CONCLUSION:LINE-1 ORF-1p promotes HepG2 cell proliferation and plays an important role in the resistance of chemotherapeutic drugs.By establishing novel roles and defining the mechanisms of LINE-1 ORF1p in HCC chemotherapeutic drug resistance and cell proliferation regulation,this study indicates that LINE-1 ORF-1p is a potential target for overcoming HCC chemotherapeutic resistance.展开更多
BACKGROUND Sorafenib is the first-line treatment for patients with advanced hepatocellular carcinoma(HCC).Y-box binding protein 1(YB-1)is closely correlated with tumors and drug resistance.However,the relationship bet...BACKGROUND Sorafenib is the first-line treatment for patients with advanced hepatocellular carcinoma(HCC).Y-box binding protein 1(YB-1)is closely correlated with tumors and drug resistance.However,the relationship between YB-1 and sorafenib resistance and the underlying mechanism in HCC remain unknown.AIM To explore the role and related mechanisms of YB-1 in mediating sorafenib resistance in HCC.METHODS The protein expression levels of YB-1 were assessed in human HCC tissues and adjacent nontumor tissues.Next,we constructed YB-1 overexpression and knockdown hepatocarcinoma cell lines with lentiviruses and stimulated these cell lines with different concentrations of sorafenib.Then,we detected the proliferation and apoptosis in these cells by terminal deoxynucleotidyl transferase dUTP nick end labeling,flow cytometry and Western blotting assays.We also constructed a xenograft tumor model to explore the effect of YB-1 on the efficacy of sorafenib in vivo.Moreover,we studied and verified the specific molecular mechanism of YB-1 mediating sorafenib resistance in hepatoma cells by digital gene expression sequencing(DGE-seq).RESULTS YB-1 protein levels were found to be higher in HCC tissues than in corresponding nontumor tissues.YB-1 suppressed the effect of sorafenib on cell proliferation and apoptosis.Consistently,the efficacy of sorafenib in vivo was enhanced after YB-1 was knocked down.Furthermore,KEGG pathway enrichment analysis of DGEseq demonstrated that the phosphoinositide-3-kinase(PI3K)/protein kinase B(Akt)signaling pathway was essential for the sorafenib resistance induced by YB-1.Subsequently,YB-1 interacted with two key proteins of the PI3K/Akt signaling pathway(Akt1 and PIK3R1)as shown by searching the BioGRID and HitPredict websites.Finally,YB-1 suppressed the inactivation of the PI3K/Akt signaling pathway induced by sorafenib,and the blockade of the PI3K/Akt signaling pathway by LY294002 mitigated YB-1-induced sorafenib resistance.CONCLUSION Overall,we concluded that YB-1 augments sorafenib resistance through the PI3K/Akt signaling pathway in HCC and suggest that YB-1 is a key drug resistance-related gene,which is of great significance for the application of sorafenib in advanced-stage HCC.展开更多
基金Natural Science Foundation of Gansu Province,No.21JR1RA186and the Health Industry Research Program of Gansu Province,No.GSWSKY2021-043.
文摘Despite the continuous developments and advancements in the treatment of gastric cancer(GC),which is one of the most prevalent types of cancer in China,the overall survival is still poor for most patients with advanced GC.In recent years,with the progress in tumor immunology research,attention has shifted toward immunotherapy as a therapeutic approach for GC.Programmed cell death protein 1(PD-1)inhibitors,as novel immunosuppressive medications,have been widely utilized in the treatment of GC.However,many patients are still resistant to PD-1 inhibitors and experience recurrence in the advanced stages of PD-1 immunotherapy.To reduce the occurrence of drug resistance and recurrence in GC patients receiving PD-1 immunotherapy,to maximize the clinical activity of immunosuppressive drugs,and to elicit a lasting immune response,it is essential to research the tumor microenvironment mechanisms leading to PD-1 inhibitor resistance in GC patients.This article reviews the progress in studying the factors influencing the resistance to PD-1 inhibitors in the GC tumor microenvironment,aiming to provide insights and a basis for reducing resistance to PD-1 inhibitors for GC patients in the future.
基金Supported by the National Natural Science Foundation of China,No. 30400431
文摘AIM： To reverse the multidrug resistance （MDR） by RNA interference （RNAi）-mediated MDRI suppression in heparoma cells.METHODS： For reversing MDR by RNAi technology, two different short hairpin RNAs （shRNAs） were designed and constructed into pGenSil-1 plasmid, respectively. They were then transfected into a highly adriarnycin-resistant HepG2 hepatorna cell line （HepG2/ADM）. The RNAi effect on MDR was evaluated by real-time PCR, cell cytotoxicity assay and rhodarnine 123 （Rh123） efflux assy. RESULTS： The stably-transfected clones showed various degrees of reversal of MDR phenotype. Surprisingly, the MDR phenotype was completely reversed in two transfected clones. CONCLUSION： MDR can be reversed by the shRNAmediated MDRI suppression in HepG2/ADM cells, which provides a valuable clue to make multidrug-resistant hepatoma cells sensitive to anti-cancer drugs.
基金supported by grants from Natural Science Foundation of Hunan Province(No.07JJ4009)Project of the Department of Science and Technology of Hunan Province(No. 2010FJ6029)+2 种基金Research and Innovation Conditions Project of Hunan Province(No.2010TT2034)125 Talent Project of the Third Xiangya Hospital of Central South Universitythe Freedom Explore Program of Central South University(No. 2011QNZT193),China
文摘Multidrug resistance（MDR） plays a major obstacle to successful gastric cancer chemotherapy.The purpose of this study was to investigate the MDR reversal effect and mechanisms of hyperthermia in combination with neferine（Nef） in adriamycin（ADM） resistant human SGC7901/ADM gastric cancer cells.The MDR cells were heated at 42℃ and 45℃ for 30 min alone or combined with 10 μg/mL Nef.The cytotoxic effect of ADM was evaluated by MTT assay.Cellular plasma membrane lipid fluidity was detected by fluorescence polarization technique.Intracellular accumulation of ADM was monitored with high performance liquid chromatography.Mdr-1 mRNA,P-glycoprotein（P-gp）,γH2AX expression and γH2AX foci formation were determined by real-time PCR,Western blot and immunocytochemical staining respectively.It was found that different heating methods induced different cytotoxic effects.Water submerged hyperthermia had the strongest cytotoxicity of ADM and Nef combined with hyperthermia had a synergistic cytotoxicity of ADM in the MDR cells.The water submerged hyperthermia increased the cell membrane fluidity.Both water submerged hyperthermia and Nef increased the intracellular accumulation of ADM.The water submerged hyperthermia and Nef down-regulated the expression of mdr-1 mRNA and P-gp.The water submerged hyperthermia could damage DNA and increase the γH2AX expression of SGC7901/ADM cells.The higher temperature was,the worse effect was.Our results show that combined treatment of hyperthermia with Nef can synergistically reverse MDR in human SGC7901/ADM gastric cancer cells.
基金Research was supported by the National Natural Science Fundation of China(30200182)973 Program of Ministry of Science and Techno1ogy,China(001CB109004).
文摘The brush border membrane vesicles (BBMVs) in midgut of Helicoverpa armigera weresuccessfully separated, and most of the Aminopeptidase N (APN) activities in BBMV werepreserved. The 3-[(3-chlor-amidopropyl) dimethylammonio]-1-propane-sulphonate (CHAPS)can enhance the dissolution of BBMV, and phosphatidylinositol-specific phosopholipase C(PI-PLC) can cleave the APN from midgut membrane. The APN was primarily purified usinga Mono-Q column. The results of immunoblotting showed that the 120 and 170kDa proteinsin the BBMV could bind Cry1Ac, and 120kDa APN was a glycosylphosphalidylinositol(GPI)-anchored protein. Two Bt-resistant strains (Bt-P, Bt-M) were obtained after beingselected for more than five years in laboratory using Bt insecticides and Bt transgeniccotton incorporated into diet separately. The resistance of Bt-P and Bt-M were 1083.3and 48.7 times that of susceptible strain. The genes encoding APN1 in midgut ofsusceptible and resistant H.armigera were cloned by PCR and RACE techniques. Theinferred amino acid sequences of APN1 possessed the common character of APN family ininsects. In comparison with APN1 in susceptible strain, three nucleotide mutations wereobserved in the APN1 of Bt-M strain and resulted in two amino acid replace in theputative protein sequences, and eight nucleotide mutations were observed in Bt-P strainand resulted in five amino acid replace.
基金Supported by the National Natural Science Foundation of China(No.81271036No.81500751)+1 种基金the Key Research Project of Shandong Province,China(No.2015GSF118121)the Natural Science Foundation of Shandong Province,China(No.ZR2015PH062)
文摘AIM：To investigate the altering expression profiles of efflux transporters such as breast cancer-resistance protein（BCRP）,lung resistance protein（LRP）,and multidrug resistance protein 1（MDR1） at the inner blood-retinal barrier（BRB） during the development of early diabetic retinopathy（DR） and/or aging in mice.METHODS：Relative m RNA and protein expression profiles of these three efflux transporters in the retina during the development of early DR and/or aging in mice were examined.The differing expression profiles of Zonula occludens 1（ ZO-1） and vascular endothelial growth factor-A（ VEGFA） in the retina as well as the perfusion characterization of fluorescein isothiocyanate（FITC）-dextran and Evans blue were examined to evaluate the integrity of the inner BRB.RESULTS：There were significant alterations in these three efflux transporters＇ expression profiles in the m RNA and protein levels of the retina during the development of diabetes mellitus and/or aging.The development of early DR was confirmed by the expression profiles of ZO-1 and VEGFA in the retina as well as the compromised integrity of the inner BRB.CONCLUSION：The expression profiles of some efflux transporters such as BCRP,LRP,and MDR1 in mice retina during diabetic and/or aging conditions are tested,and the attenuated expression of BCRP,LRP,and MDR1 along with the breakdown of the inner BRB is found,which may be linked to the pathogenesis of early DR.
文摘BACKGROUND:Sulfonylurea receptor 1(SUR1)and multidrug resistance protein 1(MRP1)are two prominent members of multidrug resistance proteins associated with insulin secretion. The aims of this study were to investigate their expression in insulinomas and their sole and synergistic effects in modulating abnormal insulin secretion. METHODS:Fasting glucose,insulin and C-peptide were measured in 11 insulinoma patients and 11 healthy controls. Prolonged oral glucose tolerance tests were performed in 6 insulinoma patients.Insulin content,SUR1 and MRP1 were detected in 11 insulinoma patients by immunohistochemistry. SUR1 and MRP1 were also detected in 6 insulinoma patients by immunofluorescence. RESULTS:Insulinoma patients presented the typical demons-trations of Whipple’s triad.Fasting glucose of each insulinoma patient was lower than 2.8 mmol/L,and simultaneous insulin and C-peptide were increased in insulinoma patients. Prolonged oral glucose tolerance tests showed that insulin secretion in insulinoma patients were also stimulated by high glucose.Immunohistochemistry and immunofluorescence staining showed that SUR1 increased,but MRP1 decreased in insulinoma compared with the adjacent islets. CONCLUSIONS:The hypersecretion of insulin in insulinomas might be,at least partially,due to the enrichment of SUR1. In contrast,MRP1,which is down-regulated in insulinomas, might reflect a negative feedback in insulin secretion.
基金supported by grants from the Major Project of Science and Technology of Guangxi Zhuang Autonomous Region(Grant No.AA22096018)the Natural Science Foundation of China(Grant Nos.82260468&81660416).
文摘Introduction:Siva-1,as a pro-apoptotic protein,has been shown to induce extensive apoptosis in a number of different cell lines.In our previous study,we showed that overexpressed Siva-1 decreased the apoptosis of gastric cancer cells.So,we believe that it can also work as an anti-apoptotic protein.The present study aimed to determine the specific role of Siva-1 in anticancer drug resistance in gastric cancer in vivo and in vitro and preliminarily reveal the mechanism.Materials and Methods:A vincristine-resistant MKN-28/VCR gastric cancer cell line with stably downregulated Siva-1 was established.The effect of Siva-1 downregulation on chemotherapeutic drug resistance was assessed by measuring the IC50 and pump rate of doxorubicin.Proliferation,apoptosis of cells,and cell cycle were detected via colony formation assay andflow cytometry,respectively.Additionally,migration and invasion of cells was detected via wound healing and transwell assays.Moreover,we determined in vivo effects of LV-Siva-1-RNAi on tumor size,and apoptotic cells in tumor tissues were detected using TUNEL and hematoxylin and eosin staining.Results:Siva-1 downregulation reduced the pump rate of doxorubicin and enhanced the response to drug treatment.Siva-1 negatively regulated proliferation and promoted apoptosis of cells by potentiality G2-M phase arresting.Inhibition of Siva-1 expression in MKN-28/VCR cells significantly weakened wound healing ability and decreased invasion ability.Poly(C)-binding protein 1(PCBP1)was identified as a Siva-1-interacting protein in yeast two-hybrid screening.Semiquantitative RT-PCR and western blotting revealed that Siva-1 downregulation could inhibit expression of PCBP1,Akt,and NF-κB and eventually decrease the expression of MDR1 and MRP1.Conclusion:The current study demonstrated that the downregulation of Siva-1,which functions as a regulator of MDR1 and MRP1 gene expression in gastric cancer cells by inhibiting PCBP1/Akt/NF-κB signaling pathway expression,enhanced the sensitivity of gastric cancer cells to certain chemotherapies.
基金Supported by: the National Natural Science Foundation of China, No. 30770737
文摘BACKGROUND： Studies have shown that scorpion venom heat-resistant protein （SVHRP） exhibits protective effects on primary cultured hippocampal neurons. OBJECTIVE： To determine the effects of SVHRP on astrocyte activity and synaptic density in the hippocampus induced by amyloid β peptide 1-40 （Aβ1-40） neurotoxicity. DESIGN, TIME AND SETTING： The randomized, controlled, animal experiment was performed at the Central Laboratory, the Laboratory of Human Anatomy, and the Laboratory of Physiology, in Dalian Medical University between March 2006 and June 2008. MATERIALS： Aβ1-40 was provided by Biosource, USA; SVHRP was a patented biological product of Dalian Medical University （No. ZL01 1 06166.9）. METHODS： A total of 27 healthy, 2-month-old, male SD rats were randomly assigned to 3 groups： control, Aβ, and SVHRP, with 9 rats in each group. Alzheimer＇s disease was simulated with 10 μg Aβ1-40 bilaterally injected into the hippocampus of the Aβ and SVHRP groups. The control group was injected with 2 μL 0.05% trifluoroacetic acid. One day following model establishment, the SVHRP group received an intraperitoneal injection of 2 μg/100 g SVHRP, while the control group and Aβ group received 0.5 mL/100 g tri-distilled water, once per day, for 10 consecutive days. MAIN OUTCOME MEASURES： At 16 days following model establishment, synaptophysin （p38） expression in CA1-CA4 regions of the rat hippocampus was determined by immunohistochemistry. Glial fibrillary acidic protein （GFAP） expression surrounding the hippocampal Aβ1-40 injected area was also detected. At 11 days following model establishment, escape latency, swimming time, and distance to target quadrant were measured using the Morris water maze. RESULTS： Compared with the control group, the Aβ group exhibited notably reduced p38 expression （P 〈 0.05） and notably increased GFAP expression in the rat hippocampus （P 〈 0.05）. Water maze results demonstrated that escape latency was prolonged （P 〈 0.05）, and swimming time and distance to the target quadrant were shortened in the Aβ group. Compared with the Aβ group, the SVHRP group exhibited notably increased p38 expression （P 〈 0.05） and notably decreased GFAP expression in the rat hippocampus （P 〈 0.05）. Water maze results demonstrated that escape latency was significantly reduced （P 〈 0.05）, and swimming time and distance to the target quadrant were significantly prolonged. CONCLUSION： SVHRP inhibited exogenous Aβ1-40-induced astrocyte activation and synaptic density decline in the rat hippocampus. Place navigation and spatial searching results showed that SVHRP blocked Aβ1-40-induced impaired learning and memory.
基金supported by the National Natural Science Foundation of China[31872674]the Jilin Talent Development Foundation Grant[20200301018RQ]the Fundamental Research Funds for the Central Universities[CGZH202206].
文摘Obesity-induced type 2 diabetes is mainly due to excessive free fatty acids leading to insulin resistance.Increasing thermogenesis is regarded as an effective strategy for hypolipidemia and hypoglycemia.Ginsenoside is a natural active component in Panax ginseng C.A.Meyer,and some of them enhance thermogenesis.However,there are few studies on the mechanism and target of ginsenosides enhancing thermogenesis.Using thermogenic protein uncoupling protein 1(UCP1)-luciferase reporter assay,we identifi ed ginsenoside F1 as a novel UCP1 activator in the ginsenosides library.Using pull down assay and inhibitor interference,we found F1 binds toβ3-adrenergic receptors(β3-AR)to enhance UCP1 expression via cAMP/PKA/CREB pathway.We also investigated the ability of F1 on energy metabolism in obesity-induced diabetic mice,including body weight,body composition and energy expenditure.The results of proteomics showed that F1 signifi cantly up-regulated thermogenesis proteins and lipolytic proteins,but down-regulated fatty acid synthesis proteins.Ginsenoside F1 increased thermogenesis and ameliorated insulin resistance specifi cally by promoting the browning of white adipose tissue in obese mice.Additionally,ginsenoside F1 improves norepinephrine-induced insulin resistance in adipocytes and hepatocytes,and shows a stronger mitochondria respiration ability than norepinephrine.These fi ndings suggest that ginsenoside F1 is a promising lead compound in the improvement of insulin resistance.
文摘BACKGROUND Breast cancer(BC) remains a public health problem. Tamoxifen(TAM) resistance has caused great difficulties for treatment of BC patients. Eukaryotic translation initiation factor 4E binding protein 1(EIF4EBP1) plays critical roles in the tumorigenesis and progression of BC. However, the expression and mechanism of EIF4EBP1 in determining the efficacy of TAM therapy in BC patients are still unclear.AIM To investigate the expression and functions of EIF4EBP1 in determining the efficacy of TAM therapy in BC patients.METHODS High-throughput sequencing data of breast tumors were downloaded from the Gene Expression Omnibus database. Differential gene expression analysis identified EIF4EBP1 to be significantly upregulated in cancer tissues. Its prognostic value was analyzed. The biological function and related pathways of EIF4EBP1 was analyzed. Subsequently, the expression of EIF4EBP1 was determined by real-time reverse transcription polymerase chain reaction and western blotting. Cell Counting Kit-8 assays, colony formation assay and wound healing assay were used to understand the phenotypes of function of EIF4EBP1.RESULTS EIF4EBP1 was upregulated in the TAM-resistant cells, and EIF4EBP1 was related to the prognosis of BC patients. Gene Set Enrichment Analysis showed that EIF4EBP1 might be involved in Hedgehog signaling pathways. Decreasing the expression of EIF4EBP1 could reverse TAM resistance, whereas overexpression of EIF4EBP1 promoted TAM resistance.CONCLUSION This study indicated that EIF4EBP1 was overexpressed in the BC and TAM-resistant cell line, which increased cell proliferation, invasion, migration and TAM resistance in BC cells.
基金Supported by The Key Scientific and Technological Research Foundation of the National Special Purpose Program,No.2008ZX10002-018
文摘AIM:To clarify the specific roles and mechanisms of long interspersed nuclear element-1 ORF-1 protein [human long interspersed nuclear element-1(LINE-1),ORF-1p] in chemotherapeutic drug resistance and cell proliferation regulation in hepatocellular carcinoma(HCC) cells.METHODS:MTT assays were performed to identify the effect of the chemotherapeutic drug toxicity on HepG2 cells.Cell proliferation inhibition and the IC 50 were calculated by the Origin 8.0 software.Western blotting assays were performed to investigate whether LINE-1 ORF-1p modulates the expression of some important genes,including p53,p27,p15,Bcl-2,mdr,and p-gp.To corroborate the proliferation and anchor-independent growth results,the HepG2 cells were analyzed by flow cytometry to investigate the effect of LINE-1 ORF1p on the apoptosis regulation.RESULTS:LINE-1 ORF-1p contributed to the resistance to several chemotherapeutic drugs(cisplatin and epirubicin) in HepG2 cells.The IC 50 of the epirubicin and cisplatin increased from 36.04 nmol/L to 59.11 nmol/L or from 37.94 nmol/L to 119.32 nmol/L.Repression of LINE-1 ORF-1p expression by the siRNA could markedly enhance the response of HepG2 cells to the epirubicin and cisplatin.The IC 50 correspondingly decreased from 28.06 nmol/L to 3.83 nmol/L or from 32.04 nmol/L to 2.89 nmol/L.Interestingly,down-regulation of LINE-1 ORF-1p level by siRNA could promote the response of HepG2 cells to the paclitaxel.The IC 50 decreased from 35.90 nmol/L to 7.36 nmol/L.However,overexpression of LINE-1 ORF-1p did not modulate the paclitaxel toxicity in HepG2 cells.Further Western blotting revealed that LINE-1 ORF-1p enhanced mdr and p-gp gene expression.As a protein arrested in the nucleus,LINE-1 ORF-1p may function through modulating transcriptional activity of some important transcription factors.Indeed,LINE-1 ORF-1p promoted HepG2 cell proliferation,anchor-independent growth and protected the cells against apoptosis through modulating the expression of p15,p21,p53,and Bcl-2 genes.CONCLUSION:LINE-1 ORF-1p promotes HepG2 cell proliferation and plays an important role in the resistance of chemotherapeutic drugs.By establishing novel roles and defining the mechanisms of LINE-1 ORF1p in HCC chemotherapeutic drug resistance and cell proliferation regulation,this study indicates that LINE-1 ORF-1p is a potential target for overcoming HCC chemotherapeutic resistance.
基金Supported by National Natural Science Foundation of China,No.81770601,No.81702324,and No.81602529Natural Science Foundation of Hebei Province,No.H2018206176 and No.H2017206141Post-graduate’s Innovation Fund Project of Hebei Province,No.CXZZBS2019121.
文摘BACKGROUND Sorafenib is the first-line treatment for patients with advanced hepatocellular carcinoma(HCC).Y-box binding protein 1(YB-1)is closely correlated with tumors and drug resistance.However,the relationship between YB-1 and sorafenib resistance and the underlying mechanism in HCC remain unknown.AIM To explore the role and related mechanisms of YB-1 in mediating sorafenib resistance in HCC.METHODS The protein expression levels of YB-1 were assessed in human HCC tissues and adjacent nontumor tissues.Next,we constructed YB-1 overexpression and knockdown hepatocarcinoma cell lines with lentiviruses and stimulated these cell lines with different concentrations of sorafenib.Then,we detected the proliferation and apoptosis in these cells by terminal deoxynucleotidyl transferase dUTP nick end labeling,flow cytometry and Western blotting assays.We also constructed a xenograft tumor model to explore the effect of YB-1 on the efficacy of sorafenib in vivo.Moreover,we studied and verified the specific molecular mechanism of YB-1 mediating sorafenib resistance in hepatoma cells by digital gene expression sequencing(DGE-seq).RESULTS YB-1 protein levels were found to be higher in HCC tissues than in corresponding nontumor tissues.YB-1 suppressed the effect of sorafenib on cell proliferation and apoptosis.Consistently,the efficacy of sorafenib in vivo was enhanced after YB-1 was knocked down.Furthermore,KEGG pathway enrichment analysis of DGEseq demonstrated that the phosphoinositide-3-kinase(PI3K)/protein kinase B(Akt)signaling pathway was essential for the sorafenib resistance induced by YB-1.Subsequently,YB-1 interacted with two key proteins of the PI3K/Akt signaling pathway(Akt1 and PIK3R1)as shown by searching the BioGRID and HitPredict websites.Finally,YB-1 suppressed the inactivation of the PI3K/Akt signaling pathway induced by sorafenib,and the blockade of the PI3K/Akt signaling pathway by LY294002 mitigated YB-1-induced sorafenib resistance.CONCLUSION Overall,we concluded that YB-1 augments sorafenib resistance through the PI3K/Akt signaling pathway in HCC and suggest that YB-1 is a key drug resistance-related gene,which is of great significance for the application of sorafenib in advanced-stage HCC.
