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
IM To study the number of AgNOR and rasp21 expression in different gastric mucosal lesions with Helicobacter pylori (Hp) infection to evaluate their biological behaviour and possible mechanism of Hp. METHODS Hp (usi...IM To study the number of AgNOR and rasp21 expression in different gastric mucosal lesions with Helicobacter pylori (Hp) infection to evaluate their biological behaviour and possible mechanism of Hp. METHODS Hp (using CLO test combined with WathinStarry staining), AgNOR (silver colloid technique) and rasp21 (monoclonal antibody and immunohistochemical staining—ABC method) were detected in 278 patients with endoscopically and pathologically confirmed gastric mucosal lesions, including chronic superficial gastritis (CSG), chronic atrophic gastritis (CAG), intestinal metaplasia (IM), dysplasia (Dys), and gastric cancer (GC). Among them, 146 cases were Hp positive, and 132 cases Hp negative. RESULTS The mean number of AgNOR in Hp positive group was significantly higher than that in Hp negative group in the gastric mucosal lesions except for CSG (P<005 or P<001). The positive rate of rasp21 expression in Hp positive group was also significantly higher than that in Hp negative group in gastric mucosal lesions except for CSG and CAG (P<005).CONCLUSION Hp+ gastric mucosal lesions have more biological behaviour of tumors. Hp may act as a promoter to activate ras gene and to stimulate cell over proliferation.展开更多
Lung cancer is currently the leading cause of cancer death in Western nations.Non-small cell lung cancer(NSCLC)represents 80%of all lung cancers,and adenocarcinoma is the predominant histological type.Despite the inte...Lung cancer is currently the leading cause of cancer death in Western nations.Non-small cell lung cancer(NSCLC)represents 80%of all lung cancers,and adenocarcinoma is the predominant histological type.Despite the intensive research carried out on this field and therapeutic advances,the overall prognosis of these patients remains unsatisfactory,with a 5-year overall survival rate of less than 15%.Nowadays,pharmacogenetics and pharmacogenomics represent the key to successful treatment.Recent studies suggest the existence of two distinct molecular pathways in the carcinogenesis of lung adenocarcinoma:one associated with smoking and activation of the K-Ras oncogene and the other not associated with smoking and activation of the epidermal growth factor receptor(EGFR).The K-ras mutation is mainly responsible for primary resistance to new molecules which inhibit tyrosine kinase EGFR(erlotinib and gefitinib)and most of the EGFR mutations are responsible for increased tumor sensitivity to these drugs.This article aims to conduct a systematic review of the literature regarding the molecular pathways involving the EGFR,K-Ras and EGFR targeted therapies in NSCLC tumor behavior.展开更多
Recent epidemiological observations have indicated that the role of Helicobacter pylori (HP) infection in the pathogenesis of gastric cancer is an important but unresolved issue. We used the polymerase chain reaction,...Recent epidemiological observations have indicated that the role of Helicobacter pylori (HP) infection in the pathogenesis of gastric cancer is an important but unresolved issue. We used the polymerase chain reaction, a sensitive and specific assay, to detect the HP infection in gastric biopsy specimens and examined the corrclations between HP infection and point mutation at 12 codon of H-ras oncogeneHras oncogene is higher in the group with HP infection than in those without HP infection. Furthermore, there is strong evidence that HP infection is associated with the increased expression of ras p21 protein , which suggested that HP infection increased the risk of ras oncogene activation. It is also noted that a significant relationship between infection with HP and the increase of DNA content and s% phase cells, indicated that rapid turnover of cells resulting from infection injury increases the risk of DNA damage.展开更多
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.
文摘IM To study the number of AgNOR and rasp21 expression in different gastric mucosal lesions with Helicobacter pylori (Hp) infection to evaluate their biological behaviour and possible mechanism of Hp. METHODS Hp (using CLO test combined with WathinStarry staining), AgNOR (silver colloid technique) and rasp21 (monoclonal antibody and immunohistochemical staining—ABC method) were detected in 278 patients with endoscopically and pathologically confirmed gastric mucosal lesions, including chronic superficial gastritis (CSG), chronic atrophic gastritis (CAG), intestinal metaplasia (IM), dysplasia (Dys), and gastric cancer (GC). Among them, 146 cases were Hp positive, and 132 cases Hp negative. RESULTS The mean number of AgNOR in Hp positive group was significantly higher than that in Hp negative group in the gastric mucosal lesions except for CSG (P<005 or P<001). The positive rate of rasp21 expression in Hp positive group was also significantly higher than that in Hp negative group in gastric mucosal lesions except for CSG and CAG (P<005).CONCLUSION Hp+ gastric mucosal lesions have more biological behaviour of tumors. Hp may act as a promoter to activate ras gene and to stimulate cell over proliferation.
文摘Lung cancer is currently the leading cause of cancer death in Western nations.Non-small cell lung cancer(NSCLC)represents 80%of all lung cancers,and adenocarcinoma is the predominant histological type.Despite the intensive research carried out on this field and therapeutic advances,the overall prognosis of these patients remains unsatisfactory,with a 5-year overall survival rate of less than 15%.Nowadays,pharmacogenetics and pharmacogenomics represent the key to successful treatment.Recent studies suggest the existence of two distinct molecular pathways in the carcinogenesis of lung adenocarcinoma:one associated with smoking and activation of the K-Ras oncogene and the other not associated with smoking and activation of the epidermal growth factor receptor(EGFR).The K-ras mutation is mainly responsible for primary resistance to new molecules which inhibit tyrosine kinase EGFR(erlotinib and gefitinib)and most of the EGFR mutations are responsible for increased tumor sensitivity to these drugs.This article aims to conduct a systematic review of the literature regarding the molecular pathways involving the EGFR,K-Ras and EGFR targeted therapies in NSCLC tumor behavior.
文摘Recent epidemiological observations have indicated that the role of Helicobacter pylori (HP) infection in the pathogenesis of gastric cancer is an important but unresolved issue. We used the polymerase chain reaction, a sensitive and specific assay, to detect the HP infection in gastric biopsy specimens and examined the corrclations between HP infection and point mutation at 12 codon of H-ras oncogeneHras oncogene is higher in the group with HP infection than in those without HP infection. Furthermore, there is strong evidence that HP infection is associated with the increased expression of ras p21 protein , which suggested that HP infection increased the risk of ras oncogene activation. It is also noted that a significant relationship between infection with HP and the increase of DNA content and s% phase cells, indicated that rapid turnover of cells resulting from infection injury increases the risk of DNA damage.
