摘要:
The interaction of blood glucose with heme proteins plays a key role in inducing diabetes, a serious disease threatening human health. In this study, we investigated the non-covalent interaction between glucose and myoglobin (Mb), both theoretically and experimentally, using molecular dynamics (MD) simulation combined with spectroscopic studies. It revealed that glucoses can occupy the side pocket of Mb, and bind closely to one of the xenon cavities in Mb, by hydrogen bonding interactions with two propionate groups of heme as well as surrounding amino acids. These interactions alter the conformation of the heme active site slightly and lead to an enhanced peroxidase activity of Mb, as determined by kinetic studies. This study provides general information for glucose-heme proteins interactions, and also for blood glucose-protein interactions for patients with diabetes.
摘要:
Zbtb7, a member of the POK protein family, is involved in tumorigenesis and cellular differentiation by acting as a crucial transcription factor, but its role in cell cycle modulation remains uncharacterized. In the present study, CDK2 and E2F4, two cell cycle regulators, are shown to be downregulated at the mRNA and protein levels by Zbtb7 in HepG2 and QGY7703 cells. Moreover, we demonstrate that the activities of CDK2 and E2F4 promoters were suppressed by the modulation of Zbtb7 levels and that Zbtb7 represses promoter activities through a mechanism involving direct binding of Zbtb7 to the promoters. Furthermore, it was identified that the site at -259 to -252 within the CDK2 promoter is responsible for Zbtb7-induced repression of the promoter activity. It was found that siRNA-induced knockdown of Zbtb7 resulted in the suppression of cell cycle progression in HepG2 and QGY7703 cells. Collectively, these data indicate that CDK2 and E2F4 are the downstream targets of Zbtb7, and Zbtb7 may be a cell cycle modulator by regulating the expression of cell cycle-associated genes in liver cancer cells.
摘要:
背景与目的:维甲酸相关孤核受体α(retinoid acid receptor related orphan receptorα,RORα)可能参与肿瘤的调控.本实验室前期研究发现,二烯丙基二硫(diallyl disulfide,DADS)可抑制人胶质瘤U251细胞增殖,其抑制增殖作用可能与诱导RORα蛋白表达上调有关.为了明确RORα在DADS抑制人胶质瘤细胞增殖中的作用,本研究采用miRNA干扰技术抑制RORα表达,观察其对DADS抑制U251细胞增殖的影响.方法:首先将RORαmiRNA转染人胶质瘤U251细胞,运用Western blot检测转染前后RORα蛋白表达情况.实验分为未转染组,脂质体转染组和RORαmiRNA转染组及分别经30 mg/L DADS处理后的3组,共6组.MTT法检测RORα表达下调对DADS抑制胶质瘤U251细胞增殖的影响.结果: Western blot结果显示,转染RORαmiRNA细胞的RORα蛋白表达(0.09±0.05)明显低于未转染组(0.81±0.11)和脂质体转染组(0.89±0.15),其蛋白表达下调了89.5%(P<0.05).MTT结果显示,U251细胞增殖活性在RORαmiRNA转染后48 h A570值为(0.98±0.15),高于未转染组(0.47±0.11)和脂质体转染组(0.45±0.10)(P<0.05),其增殖率高达108.5%.并且RORαmiRNA转染削弱了DADS对U251细胞的增殖抑制作用,转染RORαmiRNA细胞加入DADS后的细胞增殖率(A570值为0.69±0.20)明显高于DADS处理的未转染组(0.28±0.13)和脂质体转染组(0.25±0.12)(P<0.05),其抑制率由40.4%下降为29.6%.结论:miRNA干扰RORα表达可促进U251细胞增殖,并且削弱了DADS对U251细胞的增殖抑制作用,说明RORα参与了DADS抗胶质瘤U251细胞增殖的作用
关键词:
Breast Cancer;Epidermal Growth Factor Receptor;Breast Cancer Tissue;Survivin Expression;Cartilage Oligomeric Matrix Protein
摘要:
Pokemon is an oncogenic transcription factor involved in cell growth, differentiation and oncogenesis, but little is known about its role in human breast cancer. In this study, we aimed to reveal the role of Pokemon in breast cancer progression and patient survival and to understand its underlying mechanisms. Tissue microarray analysis of breast cancer tissues from patients with complete clinicopathological data and more than 20 years of follow-up were used to evaluate Pokemon expression and its correlation with the progression and prognosis of the disease. DNA microarray analysis of MCF-7 cells that overexpress Pokemon was used to identify Pokemon target genes. Chromatin immunoprecipitation (ChIP) and site-directed mutagenesis were utilized to determine how Pokemon regulates survivin expression, a target gene. Pokemon was found to be overexpressed in 158 (86.8%) of 182 breast cancer tissues, and its expression was correlated with tumor size (P = 0.0148) and lymph node metastasis (P = 0.0014). Pokemon expression led to worse overall (n = 175, P = 0.01) and disease-related (n = 79, P = 0.0134) patient survival. DNA microarray analyses revealed that in MCF-7 breast cancer cells, Pokemon regulates the expression of at least 121 genes involved in several signaling and metabolic pathways, including anti-apoptotic survivin. In clinical specimens, Pokemon and survivin expression were highly correlated (n = 49, r = 0.6799, P < 0.0001). ChIP and site-directed mutagenesis indicated that Pokemon induces survivin expression by binding to the GT boxes in its promoter. Pokemon promotes breast cancer progression by upregulating survivin expression and thus may be a potential target for the treatment of this malignancy.
作者机构:
[Gan, Runliang; Zhang, Yang; Wu, Yimou; Cheng, Ailan; Tang, Yunlian; Liu, Fang] Univ S China, Canc Res Inst, Hengyang City 421001, Hunan, Peoples R China.;[He, Rongfang] Univ S China, Dept Pathol, Affiliated Hosp 1, Hengyang 421001, Hunan, Peoples R China.
通讯机构:
[Gan, Runliang] U;Univ S China, Canc Res Inst, Hengyang City 421001, Hunan, Peoples R China.
关键词:
SCID Mouse;Lymphoproliferative Disease;Human Peripheral Blood Lymphocyte;Leukocyte Common Antigen;EBER1 Probe
摘要:
Epstein-Barr virus (EBV) has a close association with various types of human lymphomas. Animal models are essential to elucidate the pathogenesis of human EBV-associated lymphomas. The aim of the present study is to evaluate the association between human IgG concentration and EBV-associated lymphoma development in huPBL/SCID mice. Human peripheral blood lymphocytes (hu-PBL) from EBV-seropositive donors were inoculated intraperitoneally into SCID mouse. Immunohistochemical staining was used to examine differentiated antigens of tumor cells. EBV infection of the induced tumors was detected by in situ hybridization. IgG concentrations in the serums of 12 SCID mice were measured by unidirectional immunodiffusion assay. 21 out of 29 mice developed tumors in their body. Immunohistochemical staining showed that all induced tumors were LCA (leukocyte common antigen) positive, B-cell markers (CD20, CD79a) positive, and T-cell markers (both CD3 and CD45RO) negative. The tumors can be diagnosed as human B-cell lymphomas by these morphological and immunohistochemical features. In situ hybridization exhibited resultant tumor cells had EBV encoded small RNA-1 (EBER-1). Human-derived IgG could be found in the serum from SCID mice on the 15th day following hu-PBL transplantation, and IgG levels increased with the tumor development in 6 hu-PBL/SCID chimeras. Intraperitoneal transfer of hu-PBLs from EBV+ donors to SCID mice leads to high human IgG levels in mouse serum and B cell lymphomas. Our findings suggest that increasing levels of human-derived IgG in peripheral blood from hu-PBL/SCID mice could be used to monitor EBV-related human B-cell lymphoma development in experimental animals.