The cytotoxic effect of extract of camellia ptilophyllachang(ECPC) and extract of camellia sinensis(ECS) onHeLa cell line, poorly differentiated nasopharyngealcarcinoma cell line(CNE2) and gastric cancer cell line(MGC...The cytotoxic effect of extract of camellia ptilophyllachang(ECPC) and extract of camellia sinensis(ECS) onHeLa cell line, poorly differentiated nasopharyngealcarcinoma cell line(CNE2) and gastric cancer cell line(MGC-803 ) in vitro was studied using MIT assay method.The results showed that ECPC and ECS possessed significantcytotoxic effect on above three cell lines. The anticancer testin mice showed that ECPC had marked inhibitory effectagainst Ehrlich solid carcinoma(ESC) with inhibition ratesof 17. 8 48. 3% and with inhibition rates of 28. 3-54. 5% against reticular cell sarcoma(L2), and that ECShad inhibition rates of 31 . 5 -49. 4 % against ESC and 35. 8- 50% against L2. These two extracts had only marginalinhibitory effect against sarcoma- 180. The unknottingactivity of DNA topoisomerase II was inhibited completelyby ECPC and ECS at the concentration of 50 μg/ mlsuggesting that DNA topoisomerase II might be a targetenzyme of these two extracts.展开更多
Objective: To study the effect of active compound 6F and A from Pteris semipinnata L.(PsL) on the activities of DNA topoisomerase (TOPO) I and II, activities of cytosolic and membrane TPK, and expression of oncogene c...Objective: To study the effect of active compound 6F and A from Pteris semipinnata L.(PsL) on the activities of DNA topoisomerase (TOPO) I and II, activities of cytosolic and membrane TPK, and expression of oncogene c-myc in lung adenocarcinoma cells. Methods: The effect of compound 6F and A on activities of cytosolic and membrane TPK was measured by scintillation counting; the effect of compound A on expression of oncogene c-myc was determined by flow cytometry indirect fluorimetry. Results: compound 6F and A could inhibit the activities of TOPO I, and they strongly inhibited the TOPO II in 0.01 mg/L and 10.0 mg/L respectively. Compound A slightly inhibited the activities of membrane TPK, but not the cytosolic one. Compound A could inhibit the expression of oncogene c-myc. Conclusion: Topoisomerases are target of compound 6F and A. Compound A could slightly inhibit the activities of TPK, and showed an inhibitory effect on the expression of oncogene c-myc.展开更多
DNA topoisomerases are essential nuclear enzymes in correcting topological DNA errors and maintaining DNA integrity.Topoisomerase inhibitors are a significant class of cancer chemotherapeutics with a definite curative...DNA topoisomerases are essential nuclear enzymes in correcting topological DNA errors and maintaining DNA integrity.Topoisomerase inhibitors are a significant class of cancer chemotherapeutics with a definite curative effect.Natural products are a rich source of lead compounds for drug discovery,including anti-tumor drugs.In this study,we found that narciclasine(NCS),an amaryllidaceae alkaloid,is a novel inhibitor of topoisomerase I(topo I).Our data demonstrated that NCS inhibited topo I activity and reversed its unwinding effect on p-HOT DNA substrate.However,it had no obvious effect on topo II activity.The molecular mechanism of NCS inhibited topo I showed that NCS did not stabilize topo-DNA covalent complexes in cells,indicating that NCS is not a topo I poison.A blind docking result showed that NCS could bind to topo I,suggesting that NCS might be a topo I suppressor.Additionally,NCS exhibited a potent anti-proliferation effect in various cancer cells.NCS arrested the cell cycle at G_(2)/M phase and induced cell apoptosis.Our study reveals the antitumor mechanisms of NCS and provides a good foundation for the development of anti-cancer drugs based on topo I inhibition.展开更多
The activity of DNA topoisomerase Ⅱ prepared from either normal or tumor tissues were compared. It was found that the unknotting activity of the enzyme in malignant tumor cells was higher than that in normal cells. W...The activity of DNA topoisomerase Ⅱ prepared from either normal or tumor tissues were compared. It was found that the unknotting activity of the enzyme in malignant tumor cells was higher than that in normal cells. We selected some antitumor drugs including Chinese traditional medicine, and observed their effects on the unknotting activity of topoisomerase Ⅱ. The results showed that inhibition of the unknotting activity of the enzyme required very low concentrations of drugs, but much higher concentrations were required for other tested. Some antitumor drugs had no effect on the enzyme were also proved. It is interesting that carrageenan, an antiviral drug, strongly blocked the unknotting activity although its antitumor activity has not been reported.展开更多
为了筛选靶向DNA连接酶Ⅳ的抑制剂以实现更有效的基因定点插入,采用分子对接技术筛选出与前期研究中靶向DNA连接酶Ⅳ的抑制剂SCR7作用类似的小分子化合物。筛选到与化合物库一致的nocodazole、Fisetin和Methylene blue 3个小分子化合物...为了筛选靶向DNA连接酶Ⅳ的抑制剂以实现更有效的基因定点插入,采用分子对接技术筛选出与前期研究中靶向DNA连接酶Ⅳ的抑制剂SCR7作用类似的小分子化合物。筛选到与化合物库一致的nocodazole、Fisetin和Methylene blue 3个小分子化合物,通过用MSTN基因T11位点序列截断的Firefly Luciferase荧光素酶报告载体结合CRISPR/Cas9-gRNA-T11载体共转细胞,并结合不同的小分子化合物处理。结果表明,没有用小分子化合物处理时,萤火虫荧光素酶被截断的位置发生NHEJ修复,不能得到大量有活性的萤火虫荧光素酶;经过小分子化合物处理,抑制了细胞内的NHEJ,提高了HDR效率,能得到大量有活性的萤火虫荧光素酶。使用nocodazole、Methylene blue和Fisetin处理后的萤火虫荧光素酶检测结果65256.3、53713和77058.3分别是SCR7处理后的萤火虫荧光素酶检测结果41905.3的1.6、1.3和1.8倍,是没有SCR7处理后的萤火虫荧光素酶检测结果10120的6.4、5.3和7.6倍。证明所用的筛选策略正确,所筛选出的小分子化合物是具有DNA ligaseⅣ抑制活性的抑制剂,为后续研究奠定了基础。展开更多
AIM:rAAV mediated endostatin gene therapy has been examined as a new method for treating cancer.However, a sustained and high protein delivery is required to achieve the desired therapeutic effects.We evaluated the im...AIM:rAAV mediated endostatin gene therapy has been examined as a new method for treating cancer.However, a sustained and high protein delivery is required to achieve the desired therapeutic effects.We evaluated the impact of topoisomerase inhibitors in rAAV delivered endostatin gene therapy in a liver tumor model. METHODS:rAAV containing endostatin expression cassettes were transduced into hepatoma cell lines.To test whether the topoisomerase inhibitor pretreatment increased the expression of endostatin,Western blotting and ELISA were performed.The biologic activity of endostatin was confirmed by endothelial cell proliferation and tube formation assays. The anti-tumor effects of the rAAV-endostatin vector combined with a topoisomerase inhibitor,etoposide,were evaluated in a mouse liver tumor model. RESULTS:Topoisomerase inhibitors,including camptothecin and etoposide,were found to increase the endostatin exPression level in vitro.The over-expressed endostatin, as a result of pretreatment with a topoisomerase inhibitor, was also biologically active.In animal experiments,the combined therapy of topoisomerase inhibitor,etoposide with the rAAV-endostatin vector had the best tumor- suppressive effect and tumor foci were barely observed in livers of the treated mice.Pretreatment with an etoposide increased the level of endostatin in the liver and serum of rAAV-endostatin treated mice.Finally,the mice treated With rAAV-endostatin in combination with etoposide showed the longest survival among the experimental models. CONCLUSION:rAAV delivered endostatin gene therapy in combination with a topoisomerase inhibitor pretreatment is an effective modality for anticancer gene therapy.展开更多
文摘The cytotoxic effect of extract of camellia ptilophyllachang(ECPC) and extract of camellia sinensis(ECS) onHeLa cell line, poorly differentiated nasopharyngealcarcinoma cell line(CNE2) and gastric cancer cell line(MGC-803 ) in vitro was studied using MIT assay method.The results showed that ECPC and ECS possessed significantcytotoxic effect on above three cell lines. The anticancer testin mice showed that ECPC had marked inhibitory effectagainst Ehrlich solid carcinoma(ESC) with inhibition ratesof 17. 8 48. 3% and with inhibition rates of 28. 3-54. 5% against reticular cell sarcoma(L2), and that ECShad inhibition rates of 31 . 5 -49. 4 % against ESC and 35. 8- 50% against L2. These two extracts had only marginalinhibitory effect against sarcoma- 180. The unknottingactivity of DNA topoisomerase II was inhibited completelyby ECPC and ECS at the concentration of 50 μg/ mlsuggesting that DNA topoisomerase II might be a targetenzyme of these two extracts.
基金the National Natural Science Foundation of China (No. 39870900) and the key project grant from Guangdong Province Science and Te
文摘Objective: To study the effect of active compound 6F and A from Pteris semipinnata L.(PsL) on the activities of DNA topoisomerase (TOPO) I and II, activities of cytosolic and membrane TPK, and expression of oncogene c-myc in lung adenocarcinoma cells. Methods: The effect of compound 6F and A on activities of cytosolic and membrane TPK was measured by scintillation counting; the effect of compound A on expression of oncogene c-myc was determined by flow cytometry indirect fluorimetry. Results: compound 6F and A could inhibit the activities of TOPO I, and they strongly inhibited the TOPO II in 0.01 mg/L and 10.0 mg/L respectively. Compound A slightly inhibited the activities of membrane TPK, but not the cytosolic one. Compound A could inhibit the expression of oncogene c-myc. Conclusion: Topoisomerases are target of compound 6F and A. Compound A could slightly inhibit the activities of TPK, and showed an inhibitory effect on the expression of oncogene c-myc.
基金the National Natural Science Foundation of China(Grant Nos.21907044,81460559 and 82160697)Yunnan Fundamental Research Projects(Grant Nos.202101AT070155 and 202201AS070086)+2 种基金Basic Research Plan of Yunnan Provincial Science and Technology Department-Kunming Medical University(Grant Nos.202101AY070001-011,202201AY070001-003 and 202101AY070001-041)the Ten Thousand Talent Plans for Young Top-notch Talents of Yunnan Province(Hongyu Zhou,Dandan Liu),Yunnan Academician Expert Workstation(Grant No.202305AF150054)Basic Research Project of Yunnan Provincial Department of Education(Grant No.2022J0213).
文摘DNA topoisomerases are essential nuclear enzymes in correcting topological DNA errors and maintaining DNA integrity.Topoisomerase inhibitors are a significant class of cancer chemotherapeutics with a definite curative effect.Natural products are a rich source of lead compounds for drug discovery,including anti-tumor drugs.In this study,we found that narciclasine(NCS),an amaryllidaceae alkaloid,is a novel inhibitor of topoisomerase I(topo I).Our data demonstrated that NCS inhibited topo I activity and reversed its unwinding effect on p-HOT DNA substrate.However,it had no obvious effect on topo II activity.The molecular mechanism of NCS inhibited topo I showed that NCS did not stabilize topo-DNA covalent complexes in cells,indicating that NCS is not a topo I poison.A blind docking result showed that NCS could bind to topo I,suggesting that NCS might be a topo I suppressor.Additionally,NCS exhibited a potent anti-proliferation effect in various cancer cells.NCS arrested the cell cycle at G_(2)/M phase and induced cell apoptosis.Our study reveals the antitumor mechanisms of NCS and provides a good foundation for the development of anti-cancer drugs based on topo I inhibition.
文摘The activity of DNA topoisomerase Ⅱ prepared from either normal or tumor tissues were compared. It was found that the unknotting activity of the enzyme in malignant tumor cells was higher than that in normal cells. We selected some antitumor drugs including Chinese traditional medicine, and observed their effects on the unknotting activity of topoisomerase Ⅱ. The results showed that inhibition of the unknotting activity of the enzyme required very low concentrations of drugs, but much higher concentrations were required for other tested. Some antitumor drugs had no effect on the enzyme were also proved. It is interesting that carrageenan, an antiviral drug, strongly blocked the unknotting activity although its antitumor activity has not been reported.
基金Supported by a faculty research grant of Yonsei University College of Medicine for 2002,No.2002-06
文摘AIM:rAAV mediated endostatin gene therapy has been examined as a new method for treating cancer.However, a sustained and high protein delivery is required to achieve the desired therapeutic effects.We evaluated the impact of topoisomerase inhibitors in rAAV delivered endostatin gene therapy in a liver tumor model. METHODS:rAAV containing endostatin expression cassettes were transduced into hepatoma cell lines.To test whether the topoisomerase inhibitor pretreatment increased the expression of endostatin,Western blotting and ELISA were performed.The biologic activity of endostatin was confirmed by endothelial cell proliferation and tube formation assays. The anti-tumor effects of the rAAV-endostatin vector combined with a topoisomerase inhibitor,etoposide,were evaluated in a mouse liver tumor model. RESULTS:Topoisomerase inhibitors,including camptothecin and etoposide,were found to increase the endostatin exPression level in vitro.The over-expressed endostatin, as a result of pretreatment with a topoisomerase inhibitor, was also biologically active.In animal experiments,the combined therapy of topoisomerase inhibitor,etoposide with the rAAV-endostatin vector had the best tumor- suppressive effect and tumor foci were barely observed in livers of the treated mice.Pretreatment with an etoposide increased the level of endostatin in the liver and serum of rAAV-endostatin treated mice.Finally,the mice treated With rAAV-endostatin in combination with etoposide showed the longest survival among the experimental models. CONCLUSION:rAAV delivered endostatin gene therapy in combination with a topoisomerase inhibitor pretreatment is an effective modality for anticancer gene therapy.
