OBJECTIVE Low dose of actinomycin D(LDAct D)was reported as a potent P53 activator and protected normal proliferating cells during anti-mitotic chemotherapy.However,the mechanism of LDAct D on P53 activation is still ...OBJECTIVE Low dose of actinomycin D(LDAct D)was reported as a potent P53 activator and protected normal proliferating cells during anti-mitotic chemotherapy.However,the mechanism of LDAct D on P53 activation is still undetermined.In this study,the mechanism of LDAct D on the synergistic antitumor effect for cisplatin(CDDP)and P53 reactivation in KB cells was studied in detail.METHODS Cell viability was determined by MTT and LDH release.Apoptosis was determined by AnnexinⅤ-FITC/PI staining.Mitochondrial membrane potential(MMP)was detected by JC-1 stain-ing.Expression of P53,PARP,BAX,BCL-XL,PUMA,MDM2 and MDMX was detected by Western blotting(WB)and/or immunofluorescence(IF).P53-MDM2 complex was detected by ELISA.Molecular docking of receptor MDM2 and MDMX with actinomycin D(ACTD)was analyzed by Discovery Studio.RESULTS Compared with CDDP alone,P53 expression and the cytotoxicity on KB cells was significantly increased by the combination therapy.P53 regulatory proteins were increased while MMP was decreased.Meanwhile,knockdown of PUMA(P53 upregulated modulator of apoptosis)efficiently blocked the synergistic effect of LDAct D to CDDP.P53 activation was found to be accompanied with the increase of MDMX but not MDM2.Meanwhile,MDM2-P53 complex in KB cells was significantly decreased by LDAct D.Docking of both receptor MDM2 and MDMX with ACTD exhibited well established bonds with nearby amino acid residues.CONCLUSION LDAct D was probably an inhibitor of both MDM2 and MDMX.The synergistic effects of LDAct D for CDDP on KB cells depended on its effect on reactivating P53 and PUMA mediated mitochondrial apoptosis.展开更多
Aim To study the synergistic effect and mechanism of actinomycin D to the anti-cancer activity of cispl- atin on KB cells. Methods Cytotoxicity of actinomycin D on KB cells was evaluated by MTT and LDH Assay. Apoptosi...Aim To study the synergistic effect and mechanism of actinomycin D to the anti-cancer activity of cispl- atin on KB cells. Methods Cytotoxicity of actinomycin D on KB cells was evaluated by MTT and LDH Assay. Apoptosis was detected by Flow cytometry （FCM）. Expression of p53, PUMA, Bax, Bcl-2 and Bcl-xl was detected by WB （Western blot） or IF （immunofluorescence staining）. The translocation of PUMA, Bax, Bcl-2 and Bcl-xl was detected by confocal microscope. PUMA knockdown was achieved by PUMA siRNA. Results Actinomycin D synergistically enhanced the cytotoxicity of cisplatin on KB cells. Time-dependent increasing of PUMA and p53 in- duced by actinomycin D was accompanied by the translocation of PUMA and Bax/Bcl-xl in KB cells. Knockdown of PUMA effectively blocked the synergistic effect of actinomycin D to cisplatin. Conclusion Actinomycin D effi- ciently enhanced the anti-cancer activity of cisplatin on KB cells. Up-regulation of PUMA by actinomycin D is like- ly responsible for the observed synergistic effect between the two drugs. Combination of actinomycin D and cisplatin may lead to an effective cancer treatment strategy.展开更多
Actinomycin D (AMD) is an Received anticancer antibiotic that can bind selectively to both double-stranded and single-stranded DNA, and this binding greatly enhances DNA photosensitization. Using electron paramagnetic...Actinomycin D (AMD) is an Received anticancer antibiotic that can bind selectively to both double-stranded and single-stranded DNA, and this binding greatly enhances DNA photosensitization. Using electron paramagnetic resonance (EPR) in combination with spin trapping techniques, a systematic study was carried out on the reactive oxygen species generated in the photosensitization process of AMD. It was found that 1O2 and are important reactive intermediates either in solution or in DNA complexes, and the generation of these species is in competition. This finding suggests that the photodynamic action of AMD proceeds via two pathways: energy transfer (type I mechanism) and electron transfer (type II mechanism). 1O2 is the main product formed via energy transfer reaction in solution while electron transfer between the excited states of AMD and DNA becomes the predominant pathway in DNA complexes.展开更多
Actinomycin D(AMD) is well known for its specific inhibition of DNA transcription, and has been used clinically as an antitumor drug for the treatment of some highly malignant tumors. Based on the former research, two...Actinomycin D(AMD) is well known for its specific inhibition of DNA transcription, and has been used clinically as an antitumor drug for the treatment of some highly malignant tumors. Based on the former research, two [D-Phe 2] 2AMD analogs with L-MeVal(the fifth amino acid residue in the cyclic depsipeptide of AMD) substituted by D-MeVal and D-MePhe were designed to reduce the toxicity and increase the antitumor activity. Another analog in which the D-Val residue replaced with D-MeVal was designed to eliminate or to weaken the hydrogen bonds of D-Val residues between α and β rings. All three novel compounds were prepared from C terminal to N terminal in solution phase to form linear pentapeptides, and cyclized by BOP-Cl/Et 3N in DCM. Condensation of pentapeptide lactone with BMNBCA, followed by catalytic reduction, controlling oxidation by K 3Fe(CN) 6 and purification afforded the analogs as red solid. The spectrum data of all three analogs including HR-MS, 1H NMR and [α] D were given.展开更多
基金The project supported by Ministry of Science and Technology Project of International Cooperation(2011DFR31240)National Science and Technology Major Projects″Major Drug Discovery(″2012ZX09301002001001)
文摘OBJECTIVE Low dose of actinomycin D(LDAct D)was reported as a potent P53 activator and protected normal proliferating cells during anti-mitotic chemotherapy.However,the mechanism of LDAct D on P53 activation is still undetermined.In this study,the mechanism of LDAct D on the synergistic antitumor effect for cisplatin(CDDP)and P53 reactivation in KB cells was studied in detail.METHODS Cell viability was determined by MTT and LDH release.Apoptosis was determined by AnnexinⅤ-FITC/PI staining.Mitochondrial membrane potential(MMP)was detected by JC-1 stain-ing.Expression of P53,PARP,BAX,BCL-XL,PUMA,MDM2 and MDMX was detected by Western blotting(WB)and/or immunofluorescence(IF).P53-MDM2 complex was detected by ELISA.Molecular docking of receptor MDM2 and MDMX with actinomycin D(ACTD)was analyzed by Discovery Studio.RESULTS Compared with CDDP alone,P53 expression and the cytotoxicity on KB cells was significantly increased by the combination therapy.P53 regulatory proteins were increased while MMP was decreased.Meanwhile,knockdown of PUMA(P53 upregulated modulator of apoptosis)efficiently blocked the synergistic effect of LDAct D to CDDP.P53 activation was found to be accompanied with the increase of MDMX but not MDM2.Meanwhile,MDM2-P53 complex in KB cells was significantly decreased by LDAct D.Docking of both receptor MDM2 and MDMX with ACTD exhibited well established bonds with nearby amino acid residues.CONCLUSION LDAct D was probably an inhibitor of both MDM2 and MDMX.The synergistic effects of LDAct D for CDDP on KB cells depended on its effect on reactivating P53 and PUMA mediated mitochondrial apoptosis.
文摘Aim To study the synergistic effect and mechanism of actinomycin D to the anti-cancer activity of cispl- atin on KB cells. Methods Cytotoxicity of actinomycin D on KB cells was evaluated by MTT and LDH Assay. Apoptosis was detected by Flow cytometry （FCM）. Expression of p53, PUMA, Bax, Bcl-2 and Bcl-xl was detected by WB （Western blot） or IF （immunofluorescence staining）. The translocation of PUMA, Bax, Bcl-2 and Bcl-xl was detected by confocal microscope. PUMA knockdown was achieved by PUMA siRNA. Results Actinomycin D synergistically enhanced the cytotoxicity of cisplatin on KB cells. Time-dependent increasing of PUMA and p53 in- duced by actinomycin D was accompanied by the translocation of PUMA and Bax/Bcl-xl in KB cells. Knockdown of PUMA effectively blocked the synergistic effect of actinomycin D to cisplatin. Conclusion Actinomycin D effi- ciently enhanced the anti-cancer activity of cisplatin on KB cells. Up-regulation of PUMA by actinomycin D is like- ly responsible for the observed synergistic effect between the two drugs. Combination of actinomycin D and cisplatin may lead to an effective cancer treatment strategy.
文摘Actinomycin D (AMD) is an Received anticancer antibiotic that can bind selectively to both double-stranded and single-stranded DNA, and this binding greatly enhances DNA photosensitization. Using electron paramagnetic resonance (EPR) in combination with spin trapping techniques, a systematic study was carried out on the reactive oxygen species generated in the photosensitization process of AMD. It was found that 1O2 and are important reactive intermediates either in solution or in DNA complexes, and the generation of these species is in competition. This finding suggests that the photodynamic action of AMD proceeds via two pathways: energy transfer (type I mechanism) and electron transfer (type II mechanism). 1O2 is the main product formed via energy transfer reaction in solution while electron transfer between the excited states of AMD and DNA becomes the predominant pathway in DNA complexes.
文摘Actinomycin D(AMD) is well known for its specific inhibition of DNA transcription, and has been used clinically as an antitumor drug for the treatment of some highly malignant tumors. Based on the former research, two [D-Phe 2] 2AMD analogs with L-MeVal(the fifth amino acid residue in the cyclic depsipeptide of AMD) substituted by D-MeVal and D-MePhe were designed to reduce the toxicity and increase the antitumor activity. Another analog in which the D-Val residue replaced with D-MeVal was designed to eliminate or to weaken the hydrogen bonds of D-Val residues between α and β rings. All three novel compounds were prepared from C terminal to N terminal in solution phase to form linear pentapeptides, and cyclized by BOP-Cl/Et 3N in DCM. Condensation of pentapeptide lactone with BMNBCA, followed by catalytic reduction, controlling oxidation by K 3Fe(CN) 6 and purification afforded the analogs as red solid. The spectrum data of all three analogs including HR-MS, 1H NMR and [α] D were given.
