Neuroblastoma (NB) is the most common childhood cancer arising from the nervous system. Many high-risk neuroblastoma (HRNB) patients develop relapse after initial response to induction treatment and overall long term ...Neuroblastoma (NB) is the most common childhood cancer arising from the nervous system. Many high-risk neuroblastoma (HRNB) patients develop relapse after initial response to induction treatment and overall long term survival remains poor (less than 60%), emphasizing the need for new therapeutic approaches and more effective treatments. Combination therapies present a favorable approach to improve efficacy, decrease toxicity, and reduce development of drug resistance. Difluoromethylornithine (DFMO) has shown promise in recent clinical trials as a therapeutic agent in treating HRNB. Proteasomes are known to play an important role in tumor cell growth. Bortezomib was the first proteasome inhibitor shown to have anticancer activity clinically. In this study we explore the mechanistic and therapeutic effects of the novel drug combination of DFMO and bortezomib in NB. Cell proliferation studies demonstrated synergistic inhibition of NB cell growth. Bortezomib induced cleaved caspase-3 apoptotic pathway whereas DFMO induced a cytostatic effect on NB cells. Western blot analyses demonstrated down regulation of MYCN, LIN28 and NF-kB in response to DFMO and bortezomib, pathways that are important in cancer stem cells. A decrease in ATP-per-cell when treated with combination therapy suggests inhibition of glycolytic metabolism in NB cells. DFMO as a single agent or in combination with bortezomib significantly reduced tumor growth in xenograft mice. Given the lack of effective treatments, DFMO coupled with bortezomib offers a potential new therapeutic treatment for children with NB.展开更多
Objective: To clone the gene associated with apoptosis induced by an inhibitor of polyamine biosynthesis, a-difluoromethylornithime(DFMO). Methods: The differential sufbtraction sereening was used for gene cloning f...Objective: To clone the gene associated with apoptosis induced by an inhibitor of polyamine biosynthesis, a-difluoromethylornithime(DFMO). Methods: The differential sufbtraction sereening was used for gene cloning from cDNA library of HL60 cells treated by DFMO. Northern blot,morphological observation, FCM assays and ladder map of DNA electrophoresis were performed. Results: The transfectiong gene expression and activity of inducing apoptosis in the cell transfected from recombinant plasmid containing the cloned fragment df4 wasproved. Conclusion: It is suggest that df4 gene cloned in the study coul be a gene regulating apoptosis of HL60 cells.展开更多
A human colon cancer cell line Hce- 8693 was heterotransplanted in nude mice. Polyamine blosythesis Inhibitor a- dlfiuoromethylomithine (DFMO ) show a marked reproducible inhibition in this model. The size and weight ...A human colon cancer cell line Hce- 8693 was heterotransplanted in nude mice. Polyamine blosythesis Inhibitor a- dlfiuoromethylomithine (DFMO ) show a marked reproducible inhibition in this model. The size and weight of transplanted tumor In DFMO group were smaller than those of the control group and the average inhibition rate was 72.8% (P < 0.001) . DFMO showed higher tumor inhibitory rate than 5-Fu (35. 4%) (P<0. 001) . Furthermore. DFMO demonstrated less severe bone marrow inhibition in the nude mice than 5-Fu (20. 0% Vs 53. 2%. P<0. 001) .There was no synergistic action in these two drugs at the experimental dose. The concentration of putrescine and spermidine in the plasma and tumor tissue in the DFMO group were 70% lower than those of the control group (P<0. 001) . These results indicate that the anti-tumor effect of DFMO might be explained by the inhibition of polyamine biosynthesis and this study provides an experimental basis for future clinical application of DFMO.展开更多
High current findings indicate that a substitution with pyruvate can lead to significant alterations or even improvement in neutrophil immunonutrition. However, it is still unknown which intra-cellular pathways might ...High current findings indicate that a substitution with pyruvate can lead to significant alterations or even improvement in neutrophil immunonutrition. However, it is still unknown which intra-cellular pathways might be involved here. Hence, in this study, we investigated whether preincu-bation with an inhibitor of ·NO-synthase (L-NAME), an ·NO donor (SNAP), an analogue of taurine (beta-alanine), an inhibitor of ornithine-decarboxylase (DFMO) as well as a glutamine-analogue (DON), is able to alter the intragranulocytic metabolic response to pyruvate, here for example studied for neutrophil intracellular amino- and α-keto acid concentrations or important neutrophil immune functions [released myeloperoxidase (MPO), the formation of superoxide anions O2- and hydrogen peroxide (H2O2)]. In summary, the interesting first results presented here showed, that any damage of specific metabolic pathways or mechanisms, which seem directly or indirectly to be involved in relevant pyruvate dependent granulocytic nutrient content or specific cellular tasks, could lead to therapeutically desired, but also to unexpected or even fatal consequences for the affected cells. We therefore continue to believe that pyruvate, irrespective of which exact biochemical mechanisms were involved, in neutrophils may satisfy the substantial metabolic demands for a potent intracellular nutrient.展开更多
文摘Neuroblastoma (NB) is the most common childhood cancer arising from the nervous system. Many high-risk neuroblastoma (HRNB) patients develop relapse after initial response to induction treatment and overall long term survival remains poor (less than 60%), emphasizing the need for new therapeutic approaches and more effective treatments. Combination therapies present a favorable approach to improve efficacy, decrease toxicity, and reduce development of drug resistance. Difluoromethylornithine (DFMO) has shown promise in recent clinical trials as a therapeutic agent in treating HRNB. Proteasomes are known to play an important role in tumor cell growth. Bortezomib was the first proteasome inhibitor shown to have anticancer activity clinically. In this study we explore the mechanistic and therapeutic effects of the novel drug combination of DFMO and bortezomib in NB. Cell proliferation studies demonstrated synergistic inhibition of NB cell growth. Bortezomib induced cleaved caspase-3 apoptotic pathway whereas DFMO induced a cytostatic effect on NB cells. Western blot analyses demonstrated down regulation of MYCN, LIN28 and NF-kB in response to DFMO and bortezomib, pathways that are important in cancer stem cells. A decrease in ATP-per-cell when treated with combination therapy suggests inhibition of glycolytic metabolism in NB cells. DFMO as a single agent or in combination with bortezomib significantly reduced tumor growth in xenograft mice. Given the lack of effective treatments, DFMO coupled with bortezomib offers a potential new therapeutic treatment for children with NB.
文摘Objective: To clone the gene associated with apoptosis induced by an inhibitor of polyamine biosynthesis, a-difluoromethylornithime(DFMO). Methods: The differential sufbtraction sereening was used for gene cloning from cDNA library of HL60 cells treated by DFMO. Northern blot,morphological observation, FCM assays and ladder map of DNA electrophoresis were performed. Results: The transfectiong gene expression and activity of inducing apoptosis in the cell transfected from recombinant plasmid containing the cloned fragment df4 wasproved. Conclusion: It is suggest that df4 gene cloned in the study coul be a gene regulating apoptosis of HL60 cells.
文摘A human colon cancer cell line Hce- 8693 was heterotransplanted in nude mice. Polyamine blosythesis Inhibitor a- dlfiuoromethylomithine (DFMO ) show a marked reproducible inhibition in this model. The size and weight of transplanted tumor In DFMO group were smaller than those of the control group and the average inhibition rate was 72.8% (P < 0.001) . DFMO showed higher tumor inhibitory rate than 5-Fu (35. 4%) (P<0. 001) . Furthermore. DFMO demonstrated less severe bone marrow inhibition in the nude mice than 5-Fu (20. 0% Vs 53. 2%. P<0. 001) .There was no synergistic action in these two drugs at the experimental dose. The concentration of putrescine and spermidine in the plasma and tumor tissue in the DFMO group were 70% lower than those of the control group (P<0. 001) . These results indicate that the anti-tumor effect of DFMO might be explained by the inhibition of polyamine biosynthesis and this study provides an experimental basis for future clinical application of DFMO.
文摘High current findings indicate that a substitution with pyruvate can lead to significant alterations or even improvement in neutrophil immunonutrition. However, it is still unknown which intra-cellular pathways might be involved here. Hence, in this study, we investigated whether preincu-bation with an inhibitor of ·NO-synthase (L-NAME), an ·NO donor (SNAP), an analogue of taurine (beta-alanine), an inhibitor of ornithine-decarboxylase (DFMO) as well as a glutamine-analogue (DON), is able to alter the intragranulocytic metabolic response to pyruvate, here for example studied for neutrophil intracellular amino- and α-keto acid concentrations or important neutrophil immune functions [released myeloperoxidase (MPO), the formation of superoxide anions O2- and hydrogen peroxide (H2O2)]. In summary, the interesting first results presented here showed, that any damage of specific metabolic pathways or mechanisms, which seem directly or indirectly to be involved in relevant pyruvate dependent granulocytic nutrient content or specific cellular tasks, could lead to therapeutically desired, but also to unexpected or even fatal consequences for the affected cells. We therefore continue to believe that pyruvate, irrespective of which exact biochemical mechanisms were involved, in neutrophils may satisfy the substantial metabolic demands for a potent intracellular nutrient.
