The activation of the sirtuin1(SIRT1)/nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase 1(HO-1)pathway has been shown to mitigate oxidative stress-induced apoptosis and mitochondrial damage by reducing ...The activation of the sirtuin1(SIRT1)/nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase 1(HO-1)pathway has been shown to mitigate oxidative stress-induced apoptosis and mitochondrial damage by reducing reactive oxygen species(ROS)levels.Clinical trials have demonstrated that Zhongfeng Xingnao Liquid(ZFXN)ameliorates post-stroke cognitive impairment(PSCI).However,the underlying mechanism,particularly whether it involves protecting mitochondria and inhibiting apoptosis through the SIRT1/Nrf2/HO-1 pathway,remains unclear.This study employed an oxygen-glucose deprivation(OGD)cell model using SHSY5Y cells and induced PSCI in rats through modified bilateral carotid artery ligation(2VO).The effects of ZFXN on learning and memory,neuroprotective activity,mitochondrial function,oxidative stress,and the SIRT1/Nrf2/HO-1 pathway were evaluated both in vivo and in vitro.Results indicated that ZFXN significantly increased the B-cell lymphoma 2(Bcl2)/Bcl2-associated X(Bax)ratio,reduced terminal deoxynucleotidyl transferase-mediated d UTP nickend-labeling(TUNEL)+cells,and markedly improved cognition,synaptic plasticity,and neuronal function in the hippocampus and cortex.Furthermore,ZFXN exhibited potent antioxidant activity,evidenced by decreased ROS and malondialdehyde(MDA)content and increased superoxide dismutase(SOD),catalase(CAT),and glutathione(GSH)levels.ZFXN also demonstrated considerable enhancement of mitochondrial membrane potential(MMP),Tom 20 fluorescence intensity,adenosine triphosphate(ATP)and energy charge(EC)levels,and mitochondrial complexⅠandⅢactivity,thereby inhibiting mitochondrial damage.Additionally,ZFXN significantly increased SIRT1 activity and elevated SIRT1,nuclear Nrf2,and HO-1 levels.Notably,these effects were substantially counteracted when SIRT1 was suppressed by the inhibitor EX-527 in vitro.In conclusion,ZFXN alleviates PSCI by activating the SIRT1/Nrf2/HO-1 pathway and preventing mitochondrial damage.展开更多
This study examined the radiation-induced ERBB2 nuclear transport in the BT474 breast cancer cell line and the relationship between caveolin-1 and radiation-induced ERBB2 nuclear transport. The BT474 cells were treate...This study examined the radiation-induced ERBB2 nuclear transport in the BT474 breast cancer cell line and the relationship between caveolin-1 and radiation-induced ERBB2 nuclear transport. The BT474 cells were treated with herceptin (200 nmol/L), PP2 (a caveolin-1 inhibitor, 100 nmol/L) and irradiation combined or alone. Confocal microscopy was used to observe the nuclear import of ERBB2 and caveolin-1 after irradiation. Western blotting was employed to detect the expression of ERBB2, caveolin-1 and DNA-PKcs after irradiation, and immunoprecipitation to identify the ERBB2 and caveolin-1 complex before perinuclear ERBB2 localization. Confocal microscopy showed the transport of ERBB2 and caveolin-1 from the cell membrane to the nucleus 15 min after irradiation and the proteins accumulated at the perinuclear region within 45 min. Western blotting revealed that the expression levels of ERBB2, caveolin-1 and DNA-PKcs were increased after irradiation and reached a peak 45 min later. Both herceptin and PP2 treatments were found to decrease ERBB2 expression. An immune complex composed of ERBB2 and caveolin-1 was found in the herceptin group after irradiation. It was concluded that after irradiation, ERBB2 may be transported from the cell membrane to the nucleus and activate DNA-PKcs to trigger DNA double-strand break (DSB) repair; caveolin-1 may participate in this process. Treatments involving the downregulation of caveolin-1 may increase the radio-sensitization of breast cancer 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
基金supported by the Science&Technology Department of Sichuan Province(No.2019YFS0040)the Improvement Plan of“Xinglin Scholar”Scientific Research Talent,Chengdu University of Traditional Chinese Medicine(No.XKTD2022002)。
文摘The activation of the sirtuin1(SIRT1)/nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase 1(HO-1)pathway has been shown to mitigate oxidative stress-induced apoptosis and mitochondrial damage by reducing reactive oxygen species(ROS)levels.Clinical trials have demonstrated that Zhongfeng Xingnao Liquid(ZFXN)ameliorates post-stroke cognitive impairment(PSCI).However,the underlying mechanism,particularly whether it involves protecting mitochondria and inhibiting apoptosis through the SIRT1/Nrf2/HO-1 pathway,remains unclear.This study employed an oxygen-glucose deprivation(OGD)cell model using SHSY5Y cells and induced PSCI in rats through modified bilateral carotid artery ligation(2VO).The effects of ZFXN on learning and memory,neuroprotective activity,mitochondrial function,oxidative stress,and the SIRT1/Nrf2/HO-1 pathway were evaluated both in vivo and in vitro.Results indicated that ZFXN significantly increased the B-cell lymphoma 2(Bcl2)/Bcl2-associated X(Bax)ratio,reduced terminal deoxynucleotidyl transferase-mediated d UTP nickend-labeling(TUNEL)+cells,and markedly improved cognition,synaptic plasticity,and neuronal function in the hippocampus and cortex.Furthermore,ZFXN exhibited potent antioxidant activity,evidenced by decreased ROS and malondialdehyde(MDA)content and increased superoxide dismutase(SOD),catalase(CAT),and glutathione(GSH)levels.ZFXN also demonstrated considerable enhancement of mitochondrial membrane potential(MMP),Tom 20 fluorescence intensity,adenosine triphosphate(ATP)and energy charge(EC)levels,and mitochondrial complexⅠandⅢactivity,thereby inhibiting mitochondrial damage.Additionally,ZFXN significantly increased SIRT1 activity and elevated SIRT1,nuclear Nrf2,and HO-1 levels.Notably,these effects were substantially counteracted when SIRT1 was suppressed by the inhibitor EX-527 in vitro.In conclusion,ZFXN alleviates PSCI by activating the SIRT1/Nrf2/HO-1 pathway and preventing mitochondrial damage.
基金supported by grants from the National Natural Science Foundation of China(Nos.30672426 and 30801351)
文摘This study examined the radiation-induced ERBB2 nuclear transport in the BT474 breast cancer cell line and the relationship between caveolin-1 and radiation-induced ERBB2 nuclear transport. The BT474 cells were treated with herceptin (200 nmol/L), PP2 (a caveolin-1 inhibitor, 100 nmol/L) and irradiation combined or alone. Confocal microscopy was used to observe the nuclear import of ERBB2 and caveolin-1 after irradiation. Western blotting was employed to detect the expression of ERBB2, caveolin-1 and DNA-PKcs after irradiation, and immunoprecipitation to identify the ERBB2 and caveolin-1 complex before perinuclear ERBB2 localization. Confocal microscopy showed the transport of ERBB2 and caveolin-1 from the cell membrane to the nucleus 15 min after irradiation and the proteins accumulated at the perinuclear region within 45 min. Western blotting revealed that the expression levels of ERBB2, caveolin-1 and DNA-PKcs were increased after irradiation and reached a peak 45 min later. Both herceptin and PP2 treatments were found to decrease ERBB2 expression. An immune complex composed of ERBB2 and caveolin-1 was found in the herceptin group after irradiation. It was concluded that after irradiation, ERBB2 may be transported from the cell membrane to the nucleus and activate DNA-PKcs to trigger DNA double-strand break (DSB) repair; caveolin-1 may participate in this process. Treatments involving the downregulation of caveolin-1 may increase the radio-sensitization of breast cancer 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.
