目的:探讨二甲双胍通过阻断Src酪氨酸激酶(Src)/信号转导及转录激蛋白3(STAT3)信号通路诱导胃癌MGC-803细胞凋亡的机制。方法:设MGC803细胞组、氟尿嘧啶组(100.0μg·ml^-1)和二甲双胍低(80.0μg·ml^-1)、高(160.0μg·ml^...目的:探讨二甲双胍通过阻断Src酪氨酸激酶(Src)/信号转导及转录激蛋白3(STAT3)信号通路诱导胃癌MGC-803细胞凋亡的机制。方法:设MGC803细胞组、氟尿嘧啶组(100.0μg·ml^-1)和二甲双胍低(80.0μg·ml^-1)、高(160.0μg·ml^-1)剂量组,各组细胞置于CO2培养箱(37℃、5%CO2、2%O2、93%N2)。以上各组每孔设6个平行样,培养72 h。培养结束后,细胞计数试剂盒-8(CCK-8)测定细胞活力,结晶紫染色测定单克隆形成数目,Transwell室测定侵袭能力,FACScan流式细胞仪测定细胞凋亡水平,实时荧光定量PCR(RT-PCR)及蛋白质印迹法(West Blot)测定p-SRC、p-STAT3 m RNA和蛋白水平。结果:氟尿嘧啶组和二甲双胍组的吸光度(A)值、存活率水平、克隆形成数目、穿膜数、p-SRC、p-STAT3 m RNA及蛋白表达水平显著低于MGC803细胞组(P<0.05),凋亡率显著高于MGC803细胞组(P<0.05)。二甲双胍低剂量组的A值、存活率水平、克隆形成数目、穿膜数、P-SRC、P-STAT3 m RNA、蛋白表达水平显著高于氟尿嘧啶组(P<0.05),凋亡率显著低于氟尿嘧啶组(P<0.05)。二甲双胍高剂量组与氟尿嘧啶组比较差异无统计学意义(P>0.05)。结论:二甲双胍能抑制胃癌MGC-803细胞增殖,促进胃癌MGC-803细胞凋亡;其机制与二甲双胍抑制P-SRC、P-STAT3 mRNA和蛋白的表达有关。展开更多
Intracellular signals mediated by the family of receptor tyrosine kinases play pivotal roles in morphogenesis, cell fate determination and pathogenesis. Precise control of signal amplitude and duration is critical for...Intracellular signals mediated by the family of receptor tyrosine kinases play pivotal roles in morphogenesis, cell fate determination and pathogenesis. Precise control of signal amplitude and duration is critical for the fidelity and robustness of these processes. Activation of receptor tyrosine kinases by their cognate growth factors not only leads to propagation of the signal through various biochemical cascades, but also sets in motion multiple attenuation mechanisms that ulti- mately terminate the active state. Early attenuators pre-exist prior to receptor activation and they act to limit signal propagation. Subsequently, late attenuators, such as Lrig and Sprouty, are transcriptionally induced and further act to dampen the signal. Central to the process of signaling attenuation is the role of the E3 ubiquitin ligase c-Cbl. While Cbl- mediated processes of receptor ubiquitylation and endocytosis are relatively well understood, the links of Cbl to other negative regulators are just now beginning to be appreciated. Here we review some emerging interfaces between Cbl and the transcriptionally induced negative regulators Lrig and Sprouty.展开更多
AIM: To explore different roles of TGF-β (transforming growth factor beta) and bone morphogenetic proteins (BMPs)in hepatic stellate cell proliferation and trans-differentiation.METHODS: Hepatic stellate cells were i...AIM: To explore different roles of TGF-β (transforming growth factor beta) and bone morphogenetic proteins (BMPs)in hepatic stellate cell proliferation and trans-differentiation.METHODS: Hepatic stellate cells were isolated from male Sprague-Dawley rats. Sub-cultured hepatic stellate cells were employed for cell proliferation assay with WST-1 reagent and Western blot analysis with antibody against smooth muscle alpha actin (SMA).RESULTS: The results indicated that TGF-β1 significantly inhibited cell proliferation at concentration as low as 0.1 ng/ml, but both BMP-2 and BMP-4 did not affect cell proliferation at concentration as high as 10 ng/ml. The effect on hepatic stellate cell trans-differentiation was similar between TGFβ1 and BMPs. However, BMPs was more potent at transdifferentiation of hepatic stellate cells than TGF-β1. In addition, we observed that TGF-β1 transient reduced the abundance of SMA in hepatic stellate cells.CONCLUSION: TGF-β may be more important in regulation of hepatic stellate cell proliferation while BMPs may be the major cytokines regulating hepatic stellate cell transdifferentiation.展开更多
Gastrointestinal stromal tumors (GIST) are rare mesenchymal smooth muscle sarcomas that can arise anywhere within the gastrointestinal tract. Sporadic mutations within the tyrosine kinase receptors of the interstitial...Gastrointestinal stromal tumors (GIST) are rare mesenchymal smooth muscle sarcomas that can arise anywhere within the gastrointestinal tract. Sporadic mutations within the tyrosine kinase receptors of the interstitial cells of Cajal have been identified as the key molecular step in GIST carcinogenesis. Although many patients are asymptomatic, the most common associated symptoms include: abdominal pain, dyspepsia, gastric outlet obstruction, and anorexia. Rarely, GIST can perforate causing life-threatening hemoperitoneum. Most are ultimately diagnosed on cross-sectional imaging studies (i.e., computed tomography and/or magnetic resonance imaging in combination with upper endoscopy. Endoscopic ultrasonographic localization of these tumors within the smooth muscle layer and acquisition of neoplastic spindle cells harboring mutations in the c-KIT gene is pathognomonic. Curative treatment requires a complete gross resection of the tumor. Both open and minimally invasive operations have been shown to reduce recurrence rates and improve long-term survival. While there is considerable debate over whether GIST can be benign neoplasms, we believe that all GIST have malignant potential, but vary in their propensity to recur after resection and metastasize to distant organ sites. Prognostic factors include location, size (i.e., > 5 cm), grade (> 5-10 mitoses per 50 high power fields and specific mutational events that are still being defined. Adjuvant therapy with tyrosine kinase inhibitors, such as imatinib mesylate, has been shown to reduce the risk of recurrence after one year of therapy. Treatment of locally-advanced or borderline resectable gastric GIST with neoadjuvant imatinib has been shown to induce regression in a minority of patients and stabilization in the majority of cases. This treatment strategy potentially reduces the need for more extensive surgical resections and increases the number of patients eligible for curative therapy. The modern surgical treatment of gastric GIST combines the novel use of targeted therapy and aggressive minimally invasive surgical procedures to provide effective treatment for this lethal, but rare gastrointestinal malignancy.展开更多
Inositol 1,4,5-trisphosphate 3-kinase (IP3 3-kinase/IP3K) plays an important role in signal transduction in animal cellsby phosphorylating inositol 1,4,5-trisphosphate (IP3) to inositol 1,3,4,5-tetrakisphosphate (IP4)...Inositol 1,4,5-trisphosphate 3-kinase (IP3 3-kinase/IP3K) plays an important role in signal transduction in animal cellsby phosphorylating inositol 1,4,5-trisphosphate (IP3) to inositol 1,3,4,5-tetrakisphosphate (IP4). Both IP3 and IP4 arecritical second messengers which regulate calcium (Ca2+) homeostasis. Mammalian IP3Ks are involved in many biologicalprocesses, including brain development, memory, learning and so on. It is widely reported that Ca2+ is a canonicalsecond messenger in higher plants. Therefore, plant IP3K should also play a crucial role in plant development. Recently,we reported the identification of plant IP3K gene (AtIpk2β/AtIP3K) from Arabidopsis thaliana and its characterization.Here, we summarize the molecular cloning, biochemical properties and biological functions of IP3Ks from animal, yeastand plant. This review also discusses potential functions of IP3Ks in signaling crosstalk, inositol phosphate metabolism,gene transcriptional control and so on.展开更多
This study aimed at acquiring knowledge on the hypoglycemic mechanisms of sodium metavanadate (SMV) showed that the liver glucokinase and muscle hexokinase activities increased rapidly after oral SMV was given, and th...This study aimed at acquiring knowledge on the hypoglycemic mechanisms of sodium metavanadate (SMV) showed that the liver glucokinase and muscle hexokinase activities increased rapidly after oral SMV was given, and that the blood glucose level was correlated closely with the activities of the two enzymes but not with the insulin level; which indicated that SMV could improve the altered glucose phosphorylation in diabetic mice independently of stimulating insulin secretion. This was probably one of the mechanisms of hypoglycemic effects of SMV.展开更多
文摘目的:探讨二甲双胍通过阻断Src酪氨酸激酶(Src)/信号转导及转录激蛋白3(STAT3)信号通路诱导胃癌MGC-803细胞凋亡的机制。方法:设MGC803细胞组、氟尿嘧啶组(100.0μg·ml^-1)和二甲双胍低(80.0μg·ml^-1)、高(160.0μg·ml^-1)剂量组,各组细胞置于CO2培养箱(37℃、5%CO2、2%O2、93%N2)。以上各组每孔设6个平行样,培养72 h。培养结束后,细胞计数试剂盒-8(CCK-8)测定细胞活力,结晶紫染色测定单克隆形成数目,Transwell室测定侵袭能力,FACScan流式细胞仪测定细胞凋亡水平,实时荧光定量PCR(RT-PCR)及蛋白质印迹法(West Blot)测定p-SRC、p-STAT3 m RNA和蛋白水平。结果:氟尿嘧啶组和二甲双胍组的吸光度(A)值、存活率水平、克隆形成数目、穿膜数、p-SRC、p-STAT3 m RNA及蛋白表达水平显著低于MGC803细胞组(P<0.05),凋亡率显著高于MGC803细胞组(P<0.05)。二甲双胍低剂量组的A值、存活率水平、克隆形成数目、穿膜数、P-SRC、P-STAT3 m RNA、蛋白表达水平显著高于氟尿嘧啶组(P<0.05),凋亡率显著低于氟尿嘧啶组(P<0.05)。二甲双胍高剂量组与氟尿嘧啶组比较差异无统计学意义(P>0.05)。结论:二甲双胍能抑制胃癌MGC-803细胞增殖,促进胃癌MGC-803细胞凋亡;其机制与二甲双胍抑制P-SRC、P-STAT3 mRNA和蛋白的表达有关。
文摘Intracellular signals mediated by the family of receptor tyrosine kinases play pivotal roles in morphogenesis, cell fate determination and pathogenesis. Precise control of signal amplitude and duration is critical for the fidelity and robustness of these processes. Activation of receptor tyrosine kinases by their cognate growth factors not only leads to propagation of the signal through various biochemical cascades, but also sets in motion multiple attenuation mechanisms that ulti- mately terminate the active state. Early attenuators pre-exist prior to receptor activation and they act to limit signal propagation. Subsequently, late attenuators, such as Lrig and Sprouty, are transcriptionally induced and further act to dampen the signal. Central to the process of signaling attenuation is the role of the E3 ubiquitin ligase c-Cbl. While Cbl- mediated processes of receptor ubiquitylation and endocytosis are relatively well understood, the links of Cbl to other negative regulators are just now beginning to be appreciated. Here we review some emerging interfaces between Cbl and the transcriptionally induced negative regulators Lrig and Sprouty.
文摘AIM: To explore different roles of TGF-β (transforming growth factor beta) and bone morphogenetic proteins (BMPs)in hepatic stellate cell proliferation and trans-differentiation.METHODS: Hepatic stellate cells were isolated from male Sprague-Dawley rats. Sub-cultured hepatic stellate cells were employed for cell proliferation assay with WST-1 reagent and Western blot analysis with antibody against smooth muscle alpha actin (SMA).RESULTS: The results indicated that TGF-β1 significantly inhibited cell proliferation at concentration as low as 0.1 ng/ml, but both BMP-2 and BMP-4 did not affect cell proliferation at concentration as high as 10 ng/ml. The effect on hepatic stellate cell trans-differentiation was similar between TGFβ1 and BMPs. However, BMPs was more potent at transdifferentiation of hepatic stellate cells than TGF-β1. In addition, we observed that TGF-β1 transient reduced the abundance of SMA in hepatic stellate cells.CONCLUSION: TGF-β may be more important in regulation of hepatic stellate cell proliferation while BMPs may be the major cytokines regulating hepatic stellate cell transdifferentiation.
文摘Gastrointestinal stromal tumors (GIST) are rare mesenchymal smooth muscle sarcomas that can arise anywhere within the gastrointestinal tract. Sporadic mutations within the tyrosine kinase receptors of the interstitial cells of Cajal have been identified as the key molecular step in GIST carcinogenesis. Although many patients are asymptomatic, the most common associated symptoms include: abdominal pain, dyspepsia, gastric outlet obstruction, and anorexia. Rarely, GIST can perforate causing life-threatening hemoperitoneum. Most are ultimately diagnosed on cross-sectional imaging studies (i.e., computed tomography and/or magnetic resonance imaging in combination with upper endoscopy. Endoscopic ultrasonographic localization of these tumors within the smooth muscle layer and acquisition of neoplastic spindle cells harboring mutations in the c-KIT gene is pathognomonic. Curative treatment requires a complete gross resection of the tumor. Both open and minimally invasive operations have been shown to reduce recurrence rates and improve long-term survival. While there is considerable debate over whether GIST can be benign neoplasms, we believe that all GIST have malignant potential, but vary in their propensity to recur after resection and metastasize to distant organ sites. Prognostic factors include location, size (i.e., > 5 cm), grade (> 5-10 mitoses per 50 high power fields and specific mutational events that are still being defined. Adjuvant therapy with tyrosine kinase inhibitors, such as imatinib mesylate, has been shown to reduce the risk of recurrence after one year of therapy. Treatment of locally-advanced or borderline resectable gastric GIST with neoadjuvant imatinib has been shown to induce regression in a minority of patients and stabilization in the majority of cases. This treatment strategy potentially reduces the need for more extensive surgical resections and increases the number of patients eligible for curative therapy. The modern surgical treatment of gastric GIST combines the novel use of targeted therapy and aggressive minimally invasive surgical procedures to provide effective treatment for this lethal, but rare gastrointestinal malignancy.
基金This work was supported by grants from the National Natural Science Foundation of China(No.30370142)the.National Special Key Project on Functional Genomics and Biochip of China(No.2002AA2Z1002)the Project sponsored by the Scientific Research Foundation for the Returned Oversea Chinese Scholars,State Education Ministry.
文摘Inositol 1,4,5-trisphosphate 3-kinase (IP3 3-kinase/IP3K) plays an important role in signal transduction in animal cellsby phosphorylating inositol 1,4,5-trisphosphate (IP3) to inositol 1,3,4,5-tetrakisphosphate (IP4). Both IP3 and IP4 arecritical second messengers which regulate calcium (Ca2+) homeostasis. Mammalian IP3Ks are involved in many biologicalprocesses, including brain development, memory, learning and so on. It is widely reported that Ca2+ is a canonicalsecond messenger in higher plants. Therefore, plant IP3K should also play a crucial role in plant development. Recently,we reported the identification of plant IP3K gene (AtIpk2β/AtIP3K) from Arabidopsis thaliana and its characterization.Here, we summarize the molecular cloning, biochemical properties and biological functions of IP3Ks from animal, yeastand plant. This review also discusses potential functions of IP3Ks in signaling crosstalk, inositol phosphate metabolism,gene transcriptional control and so on.
文摘This study aimed at acquiring knowledge on the hypoglycemic mechanisms of sodium metavanadate (SMV) showed that the liver glucokinase and muscle hexokinase activities increased rapidly after oral SMV was given, and that the blood glucose level was correlated closely with the activities of the two enzymes but not with the insulin level; which indicated that SMV could improve the altered glucose phosphorylation in diabetic mice independently of stimulating insulin secretion. This was probably one of the mechanisms of hypoglycemic effects of SMV.
