Background and Aims:General transcription factor IIIC subunit 2(GTF3C2)is one of the polymerase III transcription-related factors.Previous studies have revealed that GTF3C2 is involved in regulating cell proliferation...Background and Aims:General transcription factor IIIC subunit 2(GTF3C2)is one of the polymerase III transcription-related factors.Previous studies have revealed that GTF3C2 is involved in regulating cell proliferation.However,the role of GTF3C2 in hepatocellular carcinoma(HCC)remains un-clear.This study aimed to determine its expression,biologi-cal function,and mechanism in HCC.Methods:The expres-sion of GTF3C2 in HCC and non-tumor tissues,along with its clinical significance,was investigated using public databases and clinical samples.Reverse transcription-quantitative poly-merase chain reaction and Western blot assays were per-formed to detect the expression of GTF3C2,ubiquitin specific peptidase 21(USP21),mitogen-activated protein kinase 2(MEK2),extracellular signal-regulated kinase 1/2(ERK1/2),and p-ERK1/2 in cells.A luciferase reporter assay was con-ducted to explore the regulatory effect of GTF3C2 on USP21 transcription.Cell Counting Kit-8,5-ethynyl-2′-deoxyuridine,and colony formation assays were performed to assess HCC cell proliferation.Subcutaneous injection of HCC cells into nude mice was used to evaluate tumor growth in vivo.Re-sults:GTF3C2 expression was upregulated in HCC tissues and was positively correlated with advanced tumor stages and high tumor grades.HCC patients with high GTF3C2 ex-pression had significantly worse survival outcomes.Knock-down of GTF3C2 suppressed the proliferation of Hep3B and HCCLM3 cells,while overexpression of GTF3C2 facilitated the proliferation of SNU449 and Huh7 cells.GTF3C2 promoted USP21 expression by activating its transcription,which sub-sequently increased the levels of MEK2 and p-ERK1/2 in HCC cells.Overexpression of both USP21 and MEK2 counteracted the GTF3C2 knockdown-induced inactivation of the ERK1/2 pathway.Moreover,GTF3C2 promoted HCC cell proliferation in vitro and tumor growth in vivo by regulating the USP21/MEK2/ERK1/2 pathway.Conclusions:Upregulation of GT-F3C2 is frequently observed in HCC tissues and predicts poor prognosis.GTF3C2 promotes HCC cell proliferation via the USP21/MEK2/ERK1/2 pathway.展开更多
Although temozolomide （TMZ） is the first-line chemotherapeutic agent for glioblastoma, it is often non-curative due to drug resistance. To overcome the resistance of glioblastoma cells to TMZ, it is imperative to id...Although temozolomide （TMZ） is the first-line chemotherapeutic agent for glioblastoma, it is often non-curative due to drug resistance. To overcome the resistance of glioblastoma cells to TMZ, it is imperative to identity prognostic markers for outcome prediction and to develop chemo-sensitizing agents. Here, the gene expression profiles of TMZ-resistant and TMZ-sensitive samples were compared by microarray analysis, and mitogen-activated protein kinase kinase 2 （MEK2） was upregulated specifically in resistant glioma cells but not in sensitive tumor cells or non-tumor tissues. Moreover, a comprehensive analysis of patient data revealed that the increased level of MEK2 expression correlated well with the advancement of glioma grade and worse prognosis in response to TMZ treatment. Furthermore, reducing the level of MEK2 in U251 glioma cell lines or xenografted glioma models through shRNA-mediated gene knockdown inhibited cell proliferation and enhanced the sensitivity of cells toward TMZ treatment. Further analysis of tumor samples from glioma patients by real-time PCR indicated that an increased MEK2 expression level was closely associated with the activation of many drug resistance genes. Finally, these resistance genes were downregulated after MEK2 was silenced in vitro, suggesting that the mechanism of MEK2-induced chemo-resistance could be mediated by the transcriptional activation of these resistance genes. Collectively, our data indicated that the expression level of MEK2 could serve as a prognostic marker for glioma chemotherapy and that MEK2 antagonists can be used as chemo-sensitizers to enhance the treatment efficacy of TMZ.展开更多
As a pivotal signal pathway,the Ras/Raf/MEK/ERK cascade can be activated by multiple extracellular stimuli and can transmit signals to diverse substrates.It remains to be elucidated how so many different signals can b...As a pivotal signal pathway,the Ras/Raf/MEK/ERK cascade can be activated by multiple extracellular stimuli and can transmit signals to diverse substrates.It remains to be elucidated how so many different signals can be variously transferred by only two MEK molecules(MEK1 and MEK2) .Because of technological limitations the complete structures of the MEKs are still unavailable.Here,we report the full-length structure of MEK2 obtained by homology modeling and molecular dynamics simulations.The simulations show that the N-terminal part of MEK2 is highly flexible and this flexibility may enable MEK2 to interact with ERKs and other ligands in diverse manners that correspond to various upstream signals and downstream consequences.展开更多
为了考察针刺对大脑中动脉闭塞大鼠神经功能和细胞凋亡的影响。将60只SD大鼠随机分为3组,假手术组(Sham)、大脑中动脉闭塞模型组(MCAO)和大脑中动脉闭塞模型+针刺组(MCAO+ACU),每组20只。MCAO+ACU组大鼠采用针刺水沟穴、百会穴和大椎穴...为了考察针刺对大脑中动脉闭塞大鼠神经功能和细胞凋亡的影响。将60只SD大鼠随机分为3组,假手术组(Sham)、大脑中动脉闭塞模型组(MCAO)和大脑中动脉闭塞模型+针刺组(MCAO+ACU),每组20只。MCAO+ACU组大鼠采用针刺水沟穴、百会穴和大椎穴进行治疗。研究发现,针刺治疗后,MCAO+ACU组的神经损伤评分显著低于MCAO组(1.33 vs 2.62)(p<0.05)。TTC染色显示,MCAO+ACU组的梗死面积比例显著低于MCAO组(21.53%vs 35.44%)(p<0.05)。TUNEL染色显示,MCAO+ACU组的海马神经细胞凋亡数显著低于MCAO组(62.14 vs 87.46)(p<0.05)。Western blotting结果显示,MCAO+ACU组的p-Raf1、p-MEK2和p-ERK1/2蛋白表达水平均显著低于MCAO组(p<0.05)。因此,本研究表明针刺的神经保护作用机制可能与抑制Raf1/MEK2/ERK1/2信号通路的活化有关。展开更多
基金supported by a grant from the Huadong Medicine Joint Funds of the Zhejiang Provincial Natural Science Foundation of China(Grant No.LHDMD23H300002).
文摘Background and Aims:General transcription factor IIIC subunit 2(GTF3C2)is one of the polymerase III transcription-related factors.Previous studies have revealed that GTF3C2 is involved in regulating cell proliferation.However,the role of GTF3C2 in hepatocellular carcinoma(HCC)remains un-clear.This study aimed to determine its expression,biologi-cal function,and mechanism in HCC.Methods:The expres-sion of GTF3C2 in HCC and non-tumor tissues,along with its clinical significance,was investigated using public databases and clinical samples.Reverse transcription-quantitative poly-merase chain reaction and Western blot assays were per-formed to detect the expression of GTF3C2,ubiquitin specific peptidase 21(USP21),mitogen-activated protein kinase 2(MEK2),extracellular signal-regulated kinase 1/2(ERK1/2),and p-ERK1/2 in cells.A luciferase reporter assay was con-ducted to explore the regulatory effect of GTF3C2 on USP21 transcription.Cell Counting Kit-8,5-ethynyl-2′-deoxyuridine,and colony formation assays were performed to assess HCC cell proliferation.Subcutaneous injection of HCC cells into nude mice was used to evaluate tumor growth in vivo.Re-sults:GTF3C2 expression was upregulated in HCC tissues and was positively correlated with advanced tumor stages and high tumor grades.HCC patients with high GTF3C2 ex-pression had significantly worse survival outcomes.Knock-down of GTF3C2 suppressed the proliferation of Hep3B and HCCLM3 cells,while overexpression of GTF3C2 facilitated the proliferation of SNU449 and Huh7 cells.GTF3C2 promoted USP21 expression by activating its transcription,which sub-sequently increased the levels of MEK2 and p-ERK1/2 in HCC cells.Overexpression of both USP21 and MEK2 counteracted the GTF3C2 knockdown-induced inactivation of the ERK1/2 pathway.Moreover,GTF3C2 promoted HCC cell proliferation in vitro and tumor growth in vivo by regulating the USP21/MEK2/ERK1/2 pathway.Conclusions:Upregulation of GT-F3C2 is frequently observed in HCC tissues and predicts poor prognosis.GTF3C2 promotes HCC cell proliferation via the USP21/MEK2/ERK1/2 pathway.
文摘Although temozolomide （TMZ） is the first-line chemotherapeutic agent for glioblastoma, it is often non-curative due to drug resistance. To overcome the resistance of glioblastoma cells to TMZ, it is imperative to identity prognostic markers for outcome prediction and to develop chemo-sensitizing agents. Here, the gene expression profiles of TMZ-resistant and TMZ-sensitive samples were compared by microarray analysis, and mitogen-activated protein kinase kinase 2 （MEK2） was upregulated specifically in resistant glioma cells but not in sensitive tumor cells or non-tumor tissues. Moreover, a comprehensive analysis of patient data revealed that the increased level of MEK2 expression correlated well with the advancement of glioma grade and worse prognosis in response to TMZ treatment. Furthermore, reducing the level of MEK2 in U251 glioma cell lines or xenografted glioma models through shRNA-mediated gene knockdown inhibited cell proliferation and enhanced the sensitivity of cells toward TMZ treatment. Further analysis of tumor samples from glioma patients by real-time PCR indicated that an increased MEK2 expression level was closely associated with the activation of many drug resistance genes. Finally, these resistance genes were downregulated after MEK2 was silenced in vitro, suggesting that the mechanism of MEK2-induced chemo-resistance could be mediated by the transcriptional activation of these resistance genes. Collectively, our data indicated that the expression level of MEK2 could serve as a prognostic marker for glioma chemotherapy and that MEK2 antagonists can be used as chemo-sensitizers to enhance the treatment efficacy of TMZ.
基金supported by the National Natural Science Foundation of China(Grant No.30670791)the National Basic Research Program of China(Grant No.2009CB918301)+1 种基金the National High Technology Research and Development Program of China(Grant No.2008AA02Z124)the State Key Laboratory of Proteomics(Grant No.SKLP-Y200810)
文摘As a pivotal signal pathway,the Ras/Raf/MEK/ERK cascade can be activated by multiple extracellular stimuli and can transmit signals to diverse substrates.It remains to be elucidated how so many different signals can be variously transferred by only two MEK molecules(MEK1 and MEK2) .Because of technological limitations the complete structures of the MEKs are still unavailable.Here,we report the full-length structure of MEK2 obtained by homology modeling and molecular dynamics simulations.The simulations show that the N-terminal part of MEK2 is highly flexible and this flexibility may enable MEK2 to interact with ERKs and other ligands in diverse manners that correspond to various upstream signals and downstream consequences.
文摘为了考察针刺对大脑中动脉闭塞大鼠神经功能和细胞凋亡的影响。将60只SD大鼠随机分为3组,假手术组(Sham)、大脑中动脉闭塞模型组(MCAO)和大脑中动脉闭塞模型+针刺组(MCAO+ACU),每组20只。MCAO+ACU组大鼠采用针刺水沟穴、百会穴和大椎穴进行治疗。研究发现,针刺治疗后,MCAO+ACU组的神经损伤评分显著低于MCAO组(1.33 vs 2.62)(p<0.05)。TTC染色显示,MCAO+ACU组的梗死面积比例显著低于MCAO组(21.53%vs 35.44%)(p<0.05)。TUNEL染色显示,MCAO+ACU组的海马神经细胞凋亡数显著低于MCAO组(62.14 vs 87.46)(p<0.05)。Western blotting结果显示,MCAO+ACU组的p-Raf1、p-MEK2和p-ERK1/2蛋白表达水平均显著低于MCAO组(p<0.05)。因此,本研究表明针刺的神经保护作用机制可能与抑制Raf1/MEK2/ERK1/2信号通路的活化有关。
