The tumor suppressor p53 is a transcription factor with a powerful antitumor activity that is controlled by its negative regulator murine double minute 2(MDM2,also termed HDM2 in humans)through a feedback mechanism.At...The tumor suppressor p53 is a transcription factor with a powerful antitumor activity that is controlled by its negative regulator murine double minute 2(MDM2,also termed HDM2 in humans)through a feedback mechanism.At the same time,TP53 is the most frequently mutated gene in human cancers.Mutant p53 proteins lose wild-type p53 tumor suppression functions but acquire new oncogenic properties,among which are deregulating cell proliferation,increasing chemoresistance,disrupting tissue architecture,and promoting migration,invasion and metastasis as well as several other pro-oncogenic activities.The oncogenic p53 mutation Y220C creates an extended surface crevice in the DNA-binding domain destabilizing p53 and causing its denaturation and aggregation.This cavity accommodates stabilizing small molecules that have therapeutic values.The development of suitable small-molecule stabilizers is one of the therapeutic strategies for reactivating the Y220C mutant protein.In this review,we summarize approaches that target p53-Y220C,including reactivating this mutation with small molecules that bind Y220C to the hydrophobic pocket and developing immunotherapies as the goal for the near future,which target tumor cells that express the p53-Y220C neoantigen.展开更多
Gynostemma(G.) pentaphyllum(Cucurbitaceae) contains various bioactive gypenosides. Ethanol extract from G. pentaphyllum(GP-EX) has been shown to have ameliorative effects on the death of dopaminergic neurons in animal...Gynostemma(G.) pentaphyllum(Cucurbitaceae) contains various bioactive gypenosides. Ethanol extract from G. pentaphyllum(GP-EX) has been shown to have ameliorative effects on the death of dopaminergic neurons in animal models of Parkinson’s disease(PD) induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-and 6-hydroxydopamine. PD patients exhibit multiple symptoms, so PD-related research should combine neurotoxin models with genetic models. In the present study, we investigated the ameliorative effects of GP-EX, including gypenosides, on the cell death of dopaminergic neurons in the midbrain of A53 T α-synuclein transgenic mouse models of PD(A53 T). Both GP-EX and gypenosides at 50 mg/kg per day were orally administered to the A53 T mice for 20 weeks.α-Synuclein-immunopositive cells and α-synuclein phosphorylation were increased in the midbrain of A53 T mice, which was reduced following treatment with GP-EX. Treatment with GP-EX modulated the reduced phosphorylation of tyrosine hydroxylase, extracellular signal-regulated kinase(ERK1/2), Bcl-2-associated death promoter(Bad) at Ser112, and c-Jun N-terminal kinase(JNK1/2) due to α-synuclein overexpression. In the A53 T group, GP-EX treatment prolonged the latency of the step-through passive avoidance test and shortened the transfer latency of the elevated plus maze test. Gypenosides treatment exhibited the effects and efficacy similar to those of GP-EX. Taken together, GP-EX, including gypenosides, has ameliorative effects on dopaminergic neuronal cell death due to the overexpression of α-synuclein by modulating ERK1/2, Bad at Ser112, and JNK1/2 signaling in the midbrain of A53 T mouse model of PD. Further studies are needed to investigate GP-EX as a treatment for neurodegenerative synucleinopathies, including PD. This study was approved by the Animal Ethics Committee of Chungbuk National University(approval No. CBNUA-956-16-01) on September 21, 2016.展开更多
Genistein, a potent antioxidant compound, protects dopaminergic neurons in a mouse model of Parkinson＇s disease. However, the mecha- nism underlying this action remains unknown. This study investigated human SH-SYSY ...Genistein, a potent antioxidant compound, protects dopaminergic neurons in a mouse model of Parkinson＇s disease. However, the mecha- nism underlying this action remains unknown. This study investigated human SH-SYSY cells overexpressing the A53T mutant of α-synuclein. Four groups of cells were assayed： a control group （without any treatment）, a genistein group （incubated with 20 μM genistein）, a rote- none group （treated with 50 μM rotenone）, and a rotenone ＋ genistein group （incubated with 20 μM genistein and then treated with 50μM rotenone）. A lactate dehydrogenase release test confirmed the protective effect of genistein, and genistein remarkably reversed mitochondrial oxidative injury caused by rotenone. Western blot assays showed that BCL-2 and Beclin ! levels were markedly higher in the genistein group than in the rotenone group. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling revealed that genistein inhibited rotenone-induced apoptosis in SH-SYSY cells. Compared with the control group, the expression of NFE2L2 and HMOX1 was significantly increased in the genistein ＋ rotenone group. However, after treatment with estrogen receptor and NFE2L2 channel blockers （ICI-182780 and ML385, respectively）, genistein could not elevate NFE2L2 and HMOX1 expression. ICI-182780 effectively prevented genistein-mediated phosphorylation of NFE2L2 and remarkably suppressed phosphorylation of AKT, a protein downstream of the estrogen receptor. These findings confirm that genistein has neuroprotective effects in a cell model of Parkinson＇s dis- ease. Genistein can reduce oxidative stress damage and cell apoptosis by activating estrogen receptors and NFE2L2 channels.展开更多
目的探讨T细胞淋巴瘤p53突变和其周围微卫星DNA的改变及两者的关系，以进一步研究T细胞淋巴瘤的分子遗传学发病机制。方法采用PCR、PCR-SSCP技术观察38例T细胞淋巴瘤的肿瘤组织及其肿瘤旁淋巴组织或同一病例的反应性增生淋巴结组织进行...目的探讨T细胞淋巴瘤p53突变和其周围微卫星DNA的改变及两者的关系，以进一步研究T细胞淋巴瘤的分子遗传学发病机制。方法采用PCR、PCR-SSCP技术观察38例T细胞淋巴瘤的肿瘤组织及其肿瘤旁淋巴组织或同一病例的反应性增生淋巴结组织进行p53基因外显子5-8的点突变研究和p53周围4个微卫星位点D17S945、D17S938、D17S947、D17S926的微卫星（microsatellite，MS）改变：微卫星不稳定性（microsatellite instability，MSI）和杂合性缺失（loss of heterozygosity，LOH）分析。结果p53基因外显子5-8总突变率为39．47％（15／38）。微卫星改变的阳性率为23．68％（9／38），LOH为7．89％（3／38）。各位点MSI、LOH频率介于2．86％-18．42％和0-5．26％。微卫星改变阳性肿瘤的p53突变率为55．56％（5／9），阴性者为34．48％（10／29）（P〉0．05）。D17S926和D17S947位点LOH阳性组与阴性组的p53突变率分别为100％、36．11％（P〉0．05）。结论T细胞淋巴瘤中存在微卫星改变和p53基因突变，两者发生无明显关系。但微卫星改变阳性的肿瘤，p53突变倾向于高发。展开更多
基金funded by the Ministry of Science and Higher Education of the Russian Federation(Grant No.075-15-2020-795 of 29.09.2020,unique project ID:RF-190220X0027).
文摘The tumor suppressor p53 is a transcription factor with a powerful antitumor activity that is controlled by its negative regulator murine double minute 2(MDM2,also termed HDM2 in humans)through a feedback mechanism.At the same time,TP53 is the most frequently mutated gene in human cancers.Mutant p53 proteins lose wild-type p53 tumor suppression functions but acquire new oncogenic properties,among which are deregulating cell proliferation,increasing chemoresistance,disrupting tissue architecture,and promoting migration,invasion and metastasis as well as several other pro-oncogenic activities.The oncogenic p53 mutation Y220C creates an extended surface crevice in the DNA-binding domain destabilizing p53 and causing its denaturation and aggregation.This cavity accommodates stabilizing small molecules that have therapeutic values.The development of suitable small-molecule stabilizers is one of the therapeutic strategies for reactivating the Y220C mutant protein.In this review,we summarize approaches that target p53-Y220C,including reactivating this mutation with small molecules that bind Y220C to the hydrophobic pocket and developing immunotherapies as the goal for the near future,which target tumor cells that express the p53-Y220C neoantigen.
基金supported by the National Research Foundation of Korea,grant No.2016R1D1A3B03930722(to MKL),Republic of Korea
文摘Gynostemma(G.) pentaphyllum(Cucurbitaceae) contains various bioactive gypenosides. Ethanol extract from G. pentaphyllum(GP-EX) has been shown to have ameliorative effects on the death of dopaminergic neurons in animal models of Parkinson’s disease(PD) induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-and 6-hydroxydopamine. PD patients exhibit multiple symptoms, so PD-related research should combine neurotoxin models with genetic models. In the present study, we investigated the ameliorative effects of GP-EX, including gypenosides, on the cell death of dopaminergic neurons in the midbrain of A53 T α-synuclein transgenic mouse models of PD(A53 T). Both GP-EX and gypenosides at 50 mg/kg per day were orally administered to the A53 T mice for 20 weeks.α-Synuclein-immunopositive cells and α-synuclein phosphorylation were increased in the midbrain of A53 T mice, which was reduced following treatment with GP-EX. Treatment with GP-EX modulated the reduced phosphorylation of tyrosine hydroxylase, extracellular signal-regulated kinase(ERK1/2), Bcl-2-associated death promoter(Bad) at Ser112, and c-Jun N-terminal kinase(JNK1/2) due to α-synuclein overexpression. In the A53 T group, GP-EX treatment prolonged the latency of the step-through passive avoidance test and shortened the transfer latency of the elevated plus maze test. Gypenosides treatment exhibited the effects and efficacy similar to those of GP-EX. Taken together, GP-EX, including gypenosides, has ameliorative effects on dopaminergic neuronal cell death due to the overexpression of α-synuclein by modulating ERK1/2, Bad at Ser112, and JNK1/2 signaling in the midbrain of A53 T mouse model of PD. Further studies are needed to investigate GP-EX as a treatment for neurodegenerative synucleinopathies, including PD. This study was approved by the Animal Ethics Committee of Chungbuk National University(approval No. CBNUA-956-16-01) on September 21, 2016.
基金supported by a grant from the National Key Research and Development Plan of China,No.2016YFC1101500the National Natural Science Foundation of China,No.11672332,11102235,8167050417+1 种基金the Key Science and Technology Support Foundation of Tianjin City of China,No.17YFZCSY00620the Natural Science Foundation of Tianjin City of China,No.15JCYBJC28600,17JCZDJC35400
文摘Genistein, a potent antioxidant compound, protects dopaminergic neurons in a mouse model of Parkinson＇s disease. However, the mecha- nism underlying this action remains unknown. This study investigated human SH-SYSY cells overexpressing the A53T mutant of α-synuclein. Four groups of cells were assayed： a control group （without any treatment）, a genistein group （incubated with 20 μM genistein）, a rote- none group （treated with 50 μM rotenone）, and a rotenone ＋ genistein group （incubated with 20 μM genistein and then treated with 50μM rotenone）. A lactate dehydrogenase release test confirmed the protective effect of genistein, and genistein remarkably reversed mitochondrial oxidative injury caused by rotenone. Western blot assays showed that BCL-2 and Beclin ! levels were markedly higher in the genistein group than in the rotenone group. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling revealed that genistein inhibited rotenone-induced apoptosis in SH-SYSY cells. Compared with the control group, the expression of NFE2L2 and HMOX1 was significantly increased in the genistein ＋ rotenone group. However, after treatment with estrogen receptor and NFE2L2 channel blockers （ICI-182780 and ML385, respectively）, genistein could not elevate NFE2L2 and HMOX1 expression. ICI-182780 effectively prevented genistein-mediated phosphorylation of NFE2L2 and remarkably suppressed phosphorylation of AKT, a protein downstream of the estrogen receptor. These findings confirm that genistein has neuroprotective effects in a cell model of Parkinson＇s dis- ease. Genistein can reduce oxidative stress damage and cell apoptosis by activating estrogen receptors and NFE2L2 channels.
文摘目的探讨T细胞淋巴瘤p53突变和其周围微卫星DNA的改变及两者的关系，以进一步研究T细胞淋巴瘤的分子遗传学发病机制。方法采用PCR、PCR-SSCP技术观察38例T细胞淋巴瘤的肿瘤组织及其肿瘤旁淋巴组织或同一病例的反应性增生淋巴结组织进行p53基因外显子5-8的点突变研究和p53周围4个微卫星位点D17S945、D17S938、D17S947、D17S926的微卫星（microsatellite，MS）改变：微卫星不稳定性（microsatellite instability，MSI）和杂合性缺失（loss of heterozygosity，LOH）分析。结果p53基因外显子5-8总突变率为39．47％（15／38）。微卫星改变的阳性率为23．68％（9／38），LOH为7．89％（3／38）。各位点MSI、LOH频率介于2．86％-18．42％和0-5．26％。微卫星改变阳性肿瘤的p53突变率为55．56％（5／9），阴性者为34．48％（10／29）（P〉0．05）。D17S926和D17S947位点LOH阳性组与阴性组的p53突变率分别为100％、36．11％（P〉0．05）。结论T细胞淋巴瘤中存在微卫星改变和p53基因突变，两者发生无明显关系。但微卫星改变阳性的肿瘤，p53突变倾向于高发。
