INTRODUCTIONThe esophageal carcinoma is a common malignanttumor in Linzhou City (Linxian) of Henan Provincein northern China.Although the etiology andnatural history of csophageal carcinoma are notclear,a substantial ...INTRODUCTIONThe esophageal carcinoma is a common malignanttumor in Linzhou City (Linxian) of Henan Provincein northern China.Although the etiology andnatural history of csophageal carcinoma are notclear,a substantial amount of evidence has beenprovided to suggest that the development of humanesophageal squamous cell carcinomas (SCC) is amultistage progressive process.An展开更多
AIM To evaluate the relationship between expression of ras, p53, bcl 2 gene products, and hepatocarcinogenesis since endotoxemia produced from lipopolysaccharide admi nistration and/or the hypophagocytic state of ...AIM To evaluate the relationship between expression of ras, p53, bcl 2 gene products, and hepatocarcinogenesis since endotoxemia produced from lipopolysaccharide admi nistration and/or the hypophagocytic state of splenectomy significantly accelerated hepatocarcinogenesis induced by thioacetamide. 〖WTH4〗METHODS〓〖WTXFZ〗The hepatocarcinoma model was induced by oral intake of 0 03% thioacetamide for six months. During the induction of hepatocarcinoma model, rats were additionally treated with splenectomy and/or lipopolysaccharide administration. The techniques of flow cytometry, immunohistochemistry and immunoelectronmicroscopy were applied to quantitative analysis of the expression of oncogene proteins. RESULTS In this model system, overexpression of ras p21 protein mainly occurred on precancerous cell population or in early stage of hepatocyte transformation. And the levels of ras p21 declined when nuclear DNA aneuploid increased. Expression of bcl 2 protein slowly and steadily rose with more hepatocytes staying in S+G2M phases as the hepatocarcinoma became more malignant. P53 was moderately expressed during the hepatocarcinogenesis. There was no statistical correlation between endotoxemia levels and the changes of ras, p53 and bcl 2 gene products. CONCLUSION Over expression of oncogene ras p21 was likely to be a precursor of the premalignant hepatocytes and it might be responsible for the initiation of hepatocarcinogenesis. Bcl 2 protein expression is proportional to the severity of the malignancies. P53 may be a key pathway on the transformation and development of hepatocarcinoma. This study confirmed the hypothesis that there are multiple genes and multiple steps involved in hepatocarcinogenesis. Expressions of oncogene proteins reflected the properties of the premalignant and malignant cells, but not directly related to endotoxemia statistically.[JP]展开更多
The monoterpene d limonene inhibit the plasma membrane associated P21 ras expression and the posttranslational isoprenylation of P21 ras , a mechanism that may contribute to its efficacy in the chemoprevent...The monoterpene d limonene inhibit the plasma membrane associated P21 ras expression and the posttranslational isoprenylation of P21 ras , a mechanism that may contribute to its efficacy in the chemoprevention and therapy of chemically induced rodent cancers and some human solid tumor cells. In the present study,the relative abilities of d limonene to inhibit membrane associated P21 ras expression in pancreas tumor cell(PaCa) was carried out with Western blotting, and the inhibition of farnesyl protein transferase (FTPase) activity during the Ras protein isoprenylation and cell proliferation were determined.Concomitantly,the effects of d limonene on P21 ras localization by immunohistochemistry and H ras oncogene expression in PaCa tumor cell line by Northern blotting were observed. The results showed that d limonene inhibited FPTase activity, thus to reduce P21H ras isoprenylation. d limonene could decrease P21 ras membrane association and increase cytosolic accumulation of P21 ras . This phenomenon was also noted when d limonene treated PaCa cells were stained immunohistochemically with anti P21 ras antibody. It is suggested that the inhibition of FPTase activity was closely related with the inhibiton of P21 ras membrane association and the alteration of P21 ras localization. Inhibition of farnesylation of P21 ras altered their intracellular localization and, hence, disrupted their biological activity,but no relationship with H ras oncogene expression was found.展开更多
MgCdc42 （Cdc42 in Magnaporthe grisea）, with high homology to ScCdc42 （Cdc42 in Saccharomyces cerevisiae）, has been demonstrated to involve in the morphogenesis and infection process. To further understand the sign...MgCdc42 （Cdc42 in Magnaporthe grisea）, with high homology to ScCdc42 （Cdc42 in Saccharomyces cerevisiae）, has been demonstrated to involve in the morphogenesis and infection process. To further understand the signaling network, the putative MgCdc42-interacting proteins were analyzed. ScCdc42-interacting protein sequences were first used to BLAST against the M. grisea genome database to retrieve their corresponding analogs. Subsequently, conserved domains of these proteins were compared and expression patterns of their encoding genes in different MgCdc42 mutation states were analyzed by semiquantitative RT-PCR. All retrieved analogs of ScCdc42-interacting proteins from the M. grisea database have conserved domains as those in S. cerevisiae. Expression of their encoding genes increased in MgCdc42CA mutant and decreased in MgCdc42KO mutant. However, MgBeml, Chin1, and MgGicl in MgCdc42DN mutant had the same expression level as that in the wild type, although MgBem4, MgBoi2, MgCdc24, MgGic2, MgRgal, and Mst20 had decreased expression level, as expected. Overall, it is concluded that there may exist a similar Cdc42 signal pathway in M. grisea as in S. cerevisiae and MgCdc42 plays a key role in the pathway.展开更多
Cdc42 is a member of the Rho subfamily of Ras-related proteins, which were among the first oncogenic proteins to be identified as playing a sig-nificant role in a variety of cellular events [Barbacaid, 1987, Ann. Rev....Cdc42 is a member of the Rho subfamily of Ras-related proteins, which were among the first oncogenic proteins to be identified as playing a sig-nificant role in a variety of cellular events [Barbacaid, 1987, Ann. Rev. Biochem]. Equally important, Protein-Protein Interactions [PPIs] involving Cdc42 continue to highlight the role of Ras-related proteins’ relevance to cancer. As these proteins have been considered incapable of being “druggable”, due to a perceived lack of binding surface[s] that are amenable to small molecule targeting, there remains limited development of therapies to tackle diseased states caused by Cdc42-stimulated hyperactivity. Thusly, it has become important to characterize molecular details, including dynamics, of PPIs involving Cdc42 that may lend themselves as potential targets for therapeutic approaches. Recently, two small molecules, ZCL278 and AZA197, have shown promise in directly targeting Cdc42 to influence PPIs that are capable of causing Cdc42-stimulated abnormal signaling. In this editorial, we highlight recent studies that show case how these two small molecules may influence Cdc42-protein interactions.展开更多
基金the National Natural Science Foundation of China,No.39840012
文摘INTRODUCTIONThe esophageal carcinoma is a common malignanttumor in Linzhou City (Linxian) of Henan Provincein northern China.Although the etiology andnatural history of csophageal carcinoma are notclear,a substantial amount of evidence has beenprovided to suggest that the development of humanesophageal squamous cell carcinomas (SCC) is amultistage progressive process.An
文摘AIM To evaluate the relationship between expression of ras, p53, bcl 2 gene products, and hepatocarcinogenesis since endotoxemia produced from lipopolysaccharide admi nistration and/or the hypophagocytic state of splenectomy significantly accelerated hepatocarcinogenesis induced by thioacetamide. 〖WTH4〗METHODS〓〖WTXFZ〗The hepatocarcinoma model was induced by oral intake of 0 03% thioacetamide for six months. During the induction of hepatocarcinoma model, rats were additionally treated with splenectomy and/or lipopolysaccharide administration. The techniques of flow cytometry, immunohistochemistry and immunoelectronmicroscopy were applied to quantitative analysis of the expression of oncogene proteins. RESULTS In this model system, overexpression of ras p21 protein mainly occurred on precancerous cell population or in early stage of hepatocyte transformation. And the levels of ras p21 declined when nuclear DNA aneuploid increased. Expression of bcl 2 protein slowly and steadily rose with more hepatocytes staying in S+G2M phases as the hepatocarcinoma became more malignant. P53 was moderately expressed during the hepatocarcinogenesis. There was no statistical correlation between endotoxemia levels and the changes of ras, p53 and bcl 2 gene products. CONCLUSION Over expression of oncogene ras p21 was likely to be a precursor of the premalignant hepatocytes and it might be responsible for the initiation of hepatocarcinogenesis. Bcl 2 protein expression is proportional to the severity of the malignancies. P53 may be a key pathway on the transformation and development of hepatocarcinoma. This study confirmed the hypothesis that there are multiple genes and multiple steps involved in hepatocarcinogenesis. Expressions of oncogene proteins reflected the properties of the premalignant and malignant cells, but not directly related to endotoxemia statistically.[JP]
文摘The monoterpene d limonene inhibit the plasma membrane associated P21 ras expression and the posttranslational isoprenylation of P21 ras , a mechanism that may contribute to its efficacy in the chemoprevention and therapy of chemically induced rodent cancers and some human solid tumor cells. In the present study,the relative abilities of d limonene to inhibit membrane associated P21 ras expression in pancreas tumor cell(PaCa) was carried out with Western blotting, and the inhibition of farnesyl protein transferase (FTPase) activity during the Ras protein isoprenylation and cell proliferation were determined.Concomitantly,the effects of d limonene on P21 ras localization by immunohistochemistry and H ras oncogene expression in PaCa tumor cell line by Northern blotting were observed. The results showed that d limonene inhibited FPTase activity, thus to reduce P21H ras isoprenylation. d limonene could decrease P21 ras membrane association and increase cytosolic accumulation of P21 ras . This phenomenon was also noted when d limonene treated PaCa cells were stained immunohistochemically with anti P21 ras antibody. It is suggested that the inhibition of FPTase activity was closely related with the inhibiton of P21 ras membrane association and the alteration of P21 ras localization. Inhibition of farnesylation of P21 ras altered their intracellular localization and, hence, disrupted their biological activity,but no relationship with H ras oncogene expression was found.
基金the National Natural Science Foundation of China to Wang Zonghua （30070030, 30470066）.
文摘MgCdc42 （Cdc42 in Magnaporthe grisea）, with high homology to ScCdc42 （Cdc42 in Saccharomyces cerevisiae）, has been demonstrated to involve in the morphogenesis and infection process. To further understand the signaling network, the putative MgCdc42-interacting proteins were analyzed. ScCdc42-interacting protein sequences were first used to BLAST against the M. grisea genome database to retrieve their corresponding analogs. Subsequently, conserved domains of these proteins were compared and expression patterns of their encoding genes in different MgCdc42 mutation states were analyzed by semiquantitative RT-PCR. All retrieved analogs of ScCdc42-interacting proteins from the M. grisea database have conserved domains as those in S. cerevisiae. Expression of their encoding genes increased in MgCdc42CA mutant and decreased in MgCdc42KO mutant. However, MgBeml, Chin1, and MgGicl in MgCdc42DN mutant had the same expression level as that in the wild type, although MgBem4, MgBoi2, MgCdc24, MgGic2, MgRgal, and Mst20 had decreased expression level, as expected. Overall, it is concluded that there may exist a similar Cdc42 signal pathway in M. grisea as in S. cerevisiae and MgCdc42 plays a key role in the pathway.
文摘Cdc42 is a member of the Rho subfamily of Ras-related proteins, which were among the first oncogenic proteins to be identified as playing a sig-nificant role in a variety of cellular events [Barbacaid, 1987, Ann. Rev. Biochem]. Equally important, Protein-Protein Interactions [PPIs] involving Cdc42 continue to highlight the role of Ras-related proteins’ relevance to cancer. As these proteins have been considered incapable of being “druggable”, due to a perceived lack of binding surface[s] that are amenable to small molecule targeting, there remains limited development of therapies to tackle diseased states caused by Cdc42-stimulated hyperactivity. Thusly, it has become important to characterize molecular details, including dynamics, of PPIs involving Cdc42 that may lend themselves as potential targets for therapeutic approaches. Recently, two small molecules, ZCL278 and AZA197, have shown promise in directly targeting Cdc42 to influence PPIs that are capable of causing Cdc42-stimulated abnormal signaling. In this editorial, we highlight recent studies that show case how these two small molecules may influence Cdc42-protein interactions.
