Danshen has been used in stroke treatment for thousands of years in China. However, the underlying mechanism still remains elusive. Neuron loss is the cardinal feature of stroke. Stimulating endogenous neurogene- sis,...Danshen has been used in stroke treatment for thousands of years in China. However, the underlying mechanism still remains elusive. Neuron loss is the cardinal feature of stroke. Stimulating endogenous neurogene- sis, especially neuronal differentiation, might potentially provide therapeutic effects to these diseases. To interpret Danshen＇ s disease-modifying effects, the effects of tanshinone 11 A （T 11 A）, the major lipophilic component of Danshen, on neuronal differentiation in rat PC12 pheochromocytoma cells and the rat embryonic cortical neural stem cells （NSCs） were observed. PC12 cells and NSCs were incubated with T II A for 7 days. To detect the neu- ronal differentiation, GAP-43 expression was detected by western blots assay and β-tubulin HI expression was de- tected by immunocytochemical staining. Results showed that T Ⅱ A dose-dependently promoted neuronal differentia- tion. T Ⅱ A activated mitogen-activated protein kinase 42/44 （MAPK42/44） and its downstream transcription fac- tor, cAMP response element-binding protein （CREB）. In addition , T Ⅱ A up-regulated the expressions of brain de- rived neurotrophic factor （BDNF） and nerve growth factor （NGF）. The MEK inhibitor and the antagonist to the re- ceptors of NGF and BDNF could partially attenuate the differentiation effects, indicating that MAPK42/44 mediated BDNF and NGF signals were involved in T Ⅱ A＇ s differentiation effects. Caveolin-1 （ CAV-1 ）, the major functional protein of membrane caveolae, plays critical roles in the endocytosis of exogenous materials. CAV1, which was ac-tivated by T Ⅱ A, might help T Ⅱ A transport across cell membrane to initiate its differentiation effects. It was prov- en by the evidences that suppressing the function of caveolin inhibited the differentiation effects of T Ⅱ A. There- fore, it was concluded that T Ⅱ A promoted neuronal differentiation partially through MAPK42/44 mediated B DNF and NEF signals in a caveolae-dependent manner.展开更多
OBJECTIVE To explore the protection mechanism of metformin and tanshinone IIA on myocardial injury.METHODS The cultured neonatal rat ventricular cells(NRVCs) were exposed to100 μmol·L^(-1) H2 O2 to simulate the ...OBJECTIVE To explore the protection mechanism of metformin and tanshinone IIA on myocardial injury.METHODS The cultured neonatal rat ventricular cells(NRVCs) were exposed to100 μmol·L^(-1) H2 O2 to simulate the in vitro model of ischemia-reperfusion injury.MTT,TUNEL and Viability/Cytotoxicity Assay were used to evaluate the effect of metformin on the viability of cardiomyocytes after treated with H2 O2.The target of miR-1 was verified by Dual luciferase reporter assay.ChIP analyses was adopted to reveal the relationship between C/EBP β and miR-1.Tanshinone IIA was administrated daily for 7 d before ligation of the left anterior descending artery(LAD) and lasted for 3 months after LAD.Whole-cell patch-clamp techniques were used to measure the inward rectifying K^(+) current(IK1) in rat isolated ventricular myocytes.GRP94,p-AMPKα,C/EBP β,CHOP,Caspase-3,Kir2.1,p38 MAPK,Cx43,MEF2 and SRF levels were analyzed by Western blot and miR-1 level was quantified by Realtime PCR.RESULTS The expression of miR-1 was significantly increased in NRVCs exposed to H2 O2 in vitro.miR-1 was shown to target the 3′-untranslated region(UTR) of GRP94,which results in the accumulation of un/misfolded proteins,leading to the endoplasmic reticulum(ER) stress.C/EBP β directly induces the upregulation of miR-1 by binding to its promoter.Furthermore,metformin,a direct allosteric AMPK activator,significantly reduces C/EBP β and miR-1 levels comparing with control group.Similarly,tanshinone IIA decreased the incidence of arrhythmias and relieved ischemia-induced injury.Moreover,tanshinone IIA depressed the elevated miR-1 level and inhibited the activation of p38 MAPK and heart special transcription factors SRF and MEF2 in ischemic cardiomyocytes.CONCLUSION Metformin protects cardiomyocytes against H_(2) O_(2) damage through AMPK/C/EBPβ/miR-1/GRP94 pathway.Tanshi.none IIA play a role in protection cardiomyocytes from ischemic injury based on inhibiting miR-1 expres.sion through p38 MAPK signal pathway.展开更多
以人自发性永生化角质形成细胞系(Ha Ca T)细胞为材料,通过CCK8和蛋白印迹法分别测定不同剂量长波紫外线(ultraviolet A,UVA)、不同浓度丹参酮ⅡA(tanshinoneⅡA,TSⅡA),以及UVA和TSⅡA共同作用下的细胞活力和促分裂素原活化蛋白激酶(mi...以人自发性永生化角质形成细胞系(Ha Ca T)细胞为材料,通过CCK8和蛋白印迹法分别测定不同剂量长波紫外线(ultraviolet A,UVA)、不同浓度丹参酮ⅡA(tanshinoneⅡA,TSⅡA),以及UVA和TSⅡA共同作用下的细胞活力和促分裂素原活化蛋白激酶(mitogenactivated protein kinase,MAPK)信号通路蛋白(p38,JNK和Erk)磷酸化水平.结果表明:在10 J/cm2的UVA照射下,细胞活力为对照组的70%左右,在20 J/cm2的UVA照射下,细胞活力仅为对照组的55%左右;低浓度的TSⅡA在正常情况下对细胞活力无影响,高浓度(85μmol/L)TSⅡA处理组的细胞活力约为对照组的70%左右.与TSⅡA或UVA单独处理相比,二者共同作用下细胞活力大大降低且差异极其显著.UVA照射提高了MAPK信号通路中的p38和JNK磷酸化水平,但是对Erk磷酸化水平没有影响;而TSⅡA可以显著提高低辐射剂量(2 J/cm2)UVA诱导下的p38和JNK的磷酸化水平.这说明UVA促进Ha Ca T细胞凋亡是通过提高p38和JNK磷酸化水平来实现的;而TSⅡA可以提高p38和JNK磷酸化水平,进一步加速UVA诱导的Ha Ca T细胞凋亡.展开更多
Multidrug resistance(MDR)develops during chemotherapy in nearly all colorectal cancerpatients.It is envisaged that reversal of MDR plays a pivotal role in the success of chemotherapy.This study investigated thepotenti...Multidrug resistance(MDR)develops during chemotherapy in nearly all colorectal cancerpatients.It is envisaged that reversal of MDR plays a pivotal role in the success of chemotherapy.This study investigated thepotential pharmacological action in reversing MDR in colon cancer cells by the two most potent tanshinones,namely cryptotanshinone and dihydrotanshinone.They targeted two common MDR mechanisms,including overexpression of P-glycoprotein(P-gp)and suppression of apoptosis.Using a bi-directional transport assay,the two tanshinones decreased P-gp-mediated digoxin effluxin Caco-2 cells.They also potentiated the cytotoxicities of doxorubicin and irinotecan in P-gp overexpressing SW620Ad300 cells via increased intracellular accumulation of both anti-cancer drugs,as a result of down-regulation of P-gp mRNA and protein levels as well as inhibition of P-gp ATPase activity.In addition,the level of apoptosis was also found to be relatively suppressed in SW620Ad300 cells as compared with the parental SW620 cells.Interestingly,although cryptotanshinone and dihydrotanshinone induced less apoptosis in SW620Ad300 cells as compared to their parental cells,they produced more autophagic cell death in these MDR cells.In this regard,the drug resistant SW620Ad300 cells were more prone to cell death in response to the anti-cancer action of thetwo tanshinones.Furthermore,the cytotoxic action of the two tanshinones was shown to be p53-independent,further demonstrated theirunique anti-cancer activities in overcoming drug resistance due to the reduction of p53 expression together with a decrease of apoptosis in colon cancer cells.Taken together,the current findings indicate a great potential for cryptotanshinone and dihydrotanshinone against MDR colon cancer cells,in spite of P-gp overexpression and suppression of apoptosis.They are promising candidates to be developed as therapeutic agents and/or as an adjuvant therapy for colorectal cancer,especially for patients with MDR cancer types.展开更多
文摘Danshen has been used in stroke treatment for thousands of years in China. However, the underlying mechanism still remains elusive. Neuron loss is the cardinal feature of stroke. Stimulating endogenous neurogene- sis, especially neuronal differentiation, might potentially provide therapeutic effects to these diseases. To interpret Danshen＇ s disease-modifying effects, the effects of tanshinone 11 A （T 11 A）, the major lipophilic component of Danshen, on neuronal differentiation in rat PC12 pheochromocytoma cells and the rat embryonic cortical neural stem cells （NSCs） were observed. PC12 cells and NSCs were incubated with T II A for 7 days. To detect the neu- ronal differentiation, GAP-43 expression was detected by western blots assay and β-tubulin HI expression was de- tected by immunocytochemical staining. Results showed that T Ⅱ A dose-dependently promoted neuronal differentia- tion. T Ⅱ A activated mitogen-activated protein kinase 42/44 （MAPK42/44） and its downstream transcription fac- tor, cAMP response element-binding protein （CREB）. In addition , T Ⅱ A up-regulated the expressions of brain de- rived neurotrophic factor （BDNF） and nerve growth factor （NGF）. The MEK inhibitor and the antagonist to the re- ceptors of NGF and BDNF could partially attenuate the differentiation effects, indicating that MAPK42/44 mediated BDNF and NGF signals were involved in T Ⅱ A＇ s differentiation effects. Caveolin-1 （ CAV-1 ）, the major functional protein of membrane caveolae, plays critical roles in the endocytosis of exogenous materials. CAV1, which was ac-tivated by T Ⅱ A, might help T Ⅱ A transport across cell membrane to initiate its differentiation effects. It was prov- en by the evidences that suppressing the function of caveolin inhibited the differentiation effects of T Ⅱ A. There- fore, it was concluded that T Ⅱ A promoted neuronal differentiation partially through MAPK42/44 mediated B DNF and NEF signals in a caveolae-dependent manner.
基金supported by National Natural Science Foundation of China(8167023881570399)
文摘OBJECTIVE To explore the protection mechanism of metformin and tanshinone IIA on myocardial injury.METHODS The cultured neonatal rat ventricular cells(NRVCs) were exposed to100 μmol·L^(-1) H2 O2 to simulate the in vitro model of ischemia-reperfusion injury.MTT,TUNEL and Viability/Cytotoxicity Assay were used to evaluate the effect of metformin on the viability of cardiomyocytes after treated with H2 O2.The target of miR-1 was verified by Dual luciferase reporter assay.ChIP analyses was adopted to reveal the relationship between C/EBP β and miR-1.Tanshinone IIA was administrated daily for 7 d before ligation of the left anterior descending artery(LAD) and lasted for 3 months after LAD.Whole-cell patch-clamp techniques were used to measure the inward rectifying K^(+) current(IK1) in rat isolated ventricular myocytes.GRP94,p-AMPKα,C/EBP β,CHOP,Caspase-3,Kir2.1,p38 MAPK,Cx43,MEF2 and SRF levels were analyzed by Western blot and miR-1 level was quantified by Realtime PCR.RESULTS The expression of miR-1 was significantly increased in NRVCs exposed to H2 O2 in vitro.miR-1 was shown to target the 3′-untranslated region(UTR) of GRP94,which results in the accumulation of un/misfolded proteins,leading to the endoplasmic reticulum(ER) stress.C/EBP β directly induces the upregulation of miR-1 by binding to its promoter.Furthermore,metformin,a direct allosteric AMPK activator,significantly reduces C/EBP β and miR-1 levels comparing with control group.Similarly,tanshinone IIA decreased the incidence of arrhythmias and relieved ischemia-induced injury.Moreover,tanshinone IIA depressed the elevated miR-1 level and inhibited the activation of p38 MAPK and heart special transcription factors SRF and MEF2 in ischemic cardiomyocytes.CONCLUSION Metformin protects cardiomyocytes against H_(2) O_(2) damage through AMPK/C/EBPβ/miR-1/GRP94 pathway.Tanshi.none IIA play a role in protection cardiomyocytes from ischemic injury based on inhibiting miR-1 expres.sion through p38 MAPK signal pathway.
文摘以人自发性永生化角质形成细胞系(Ha Ca T)细胞为材料,通过CCK8和蛋白印迹法分别测定不同剂量长波紫外线(ultraviolet A,UVA)、不同浓度丹参酮ⅡA(tanshinoneⅡA,TSⅡA),以及UVA和TSⅡA共同作用下的细胞活力和促分裂素原活化蛋白激酶(mitogenactivated protein kinase,MAPK)信号通路蛋白(p38,JNK和Erk)磷酸化水平.结果表明:在10 J/cm2的UVA照射下,细胞活力为对照组的70%左右,在20 J/cm2的UVA照射下,细胞活力仅为对照组的55%左右;低浓度的TSⅡA在正常情况下对细胞活力无影响,高浓度(85μmol/L)TSⅡA处理组的细胞活力约为对照组的70%左右.与TSⅡA或UVA单独处理相比,二者共同作用下细胞活力大大降低且差异极其显著.UVA照射提高了MAPK信号通路中的p38和JNK磷酸化水平,但是对Erk磷酸化水平没有影响;而TSⅡA可以显著提高低辐射剂量(2 J/cm2)UVA诱导下的p38和JNK的磷酸化水平.这说明UVA促进Ha Ca T细胞凋亡是通过提高p38和JNK磷酸化水平来实现的;而TSⅡA可以提高p38和JNK磷酸化水平,进一步加速UVA诱导的Ha Ca T细胞凋亡.
基金The project supported by the Hong Kong Research Grants Council and the Innovation Technology Commission
文摘Multidrug resistance(MDR)develops during chemotherapy in nearly all colorectal cancerpatients.It is envisaged that reversal of MDR plays a pivotal role in the success of chemotherapy.This study investigated thepotential pharmacological action in reversing MDR in colon cancer cells by the two most potent tanshinones,namely cryptotanshinone and dihydrotanshinone.They targeted two common MDR mechanisms,including overexpression of P-glycoprotein(P-gp)and suppression of apoptosis.Using a bi-directional transport assay,the two tanshinones decreased P-gp-mediated digoxin effluxin Caco-2 cells.They also potentiated the cytotoxicities of doxorubicin and irinotecan in P-gp overexpressing SW620Ad300 cells via increased intracellular accumulation of both anti-cancer drugs,as a result of down-regulation of P-gp mRNA and protein levels as well as inhibition of P-gp ATPase activity.In addition,the level of apoptosis was also found to be relatively suppressed in SW620Ad300 cells as compared with the parental SW620 cells.Interestingly,although cryptotanshinone and dihydrotanshinone induced less apoptosis in SW620Ad300 cells as compared to their parental cells,they produced more autophagic cell death in these MDR cells.In this regard,the drug resistant SW620Ad300 cells were more prone to cell death in response to the anti-cancer action of thetwo tanshinones.Furthermore,the cytotoxic action of the two tanshinones was shown to be p53-independent,further demonstrated theirunique anti-cancer activities in overcoming drug resistance due to the reduction of p53 expression together with a decrease of apoptosis in colon cancer cells.Taken together,the current findings indicate a great potential for cryptotanshinone and dihydrotanshinone against MDR colon cancer cells,in spite of P-gp overexpression and suppression of apoptosis.They are promising candidates to be developed as therapeutic agents and/or as an adjuvant therapy for colorectal cancer,especially for patients with MDR cancer types.
