Compared to their linear counterparts,cyclic peptides show better biological activities,such as antibacterial,immunosuppressive,and anti-tumor activities,and pharmaceutical properties due to their conformational rigid...Compared to their linear counterparts,cyclic peptides show better biological activities,such as antibacterial,immunosuppressive,and anti-tumor activities,and pharmaceutical properties due to their conformational rigidity.However,cyclic peptides could form numerous putative metabolites from potential hydrolytic cleavages and their fragments are very difficult to interpret.These characteristics pose a great challenge when analyzing metabolites of cyclic peptides by mass spectrometry.This study was to assess and apply a software-aided analytical workflow for the detection and structural characterization of cyclic peptide metabolites.Insulin and atrial natriuretic peptide(ANP)as model cyclic peptides were incubated with trypsin/chymotrypsin and/or rat liver S9,followed by data acquisition using TripleTOF?5600.Resultant full-scan MS and MS/MS datasets were automatically processed through a combination of targeted and untargeted peak finding strategies.MS/MS spectra of predicted metabolites were interrogated against putative metabolite sequences,in light of a,b,y and internal fragment series.The resulting fragment assignments led to the confirmation and ranking of the metabolite sequences and identification of metabolic modification.As a result,29 metabolites with linear or cyclic structures were detected in the insulin incubation with the hydrolytic enzymes.Sequences of twenty insulin metabolites were further determined,which were consistent with the hydrolytic sites of these enzymes.In the same manner,multiple metabolites of insulin and ANP formed in rat liver S9 incubation were detected and structurally characterized,some of which have not been previously reported.The results demonstrated the utility of software-aided data processing tool in detection and identification of cyclic peptide metabolites.展开更多
To assess targeting of an epothilone folate conjugate(BMS-753493) to the folate receptor(FR)-overexpressed tumor in mice bearing both FRt and FR– tumors,a series of experiments were conducted by quantitative whole-bo...To assess targeting of an epothilone folate conjugate(BMS-753493) to the folate receptor(FR)-overexpressed tumor in mice bearing both FRt and FR– tumors,a series of experiments were conducted by quantitative whole-body autoradiography(QWBA) and LC–MS/MS following i.v.administration of BMS-753493 or its active moiety,BMS-748285 in mice bearing FRt(98M109) and FR–(M109) tumors.QWBA showed [3H]BMS-753493–derived radioactivity was extensively distributed to various tissues.The FR over-expressing 98M109 tumors showed consistently higher level of radioactivity than FR-negative tumors(i.e.,M109 tumors) up to 48 h post dose of [3H]BMS-753493,despite the magnitude of difference between the tumors is relatively small(generally 3 5-fold).The radioactivity level in 98M109 tumors was 2 12-fold of normal tissues except intestine/content at 48 h post dose.No selective radioactivity uptake into 98M109 tumors over M109 or normal tissues was observed after i.v.administration of the active epothilone,[3H]BMS-748285.LC–MS/MS measurements demonstrated that the concentrations of BMS-748285,presumably from hydrolysis of the folate conjugate,in 98M109 tumors were greater than those in M109 tumors after i.v.administration of BMS-753493(2–3-fold) whereas no differential uptake in the tumors following BMS-748285 administration.Those data were consistent with radioactivity determinations.Those results demonstrated that the folate conjugation in BMS-753493 enabled moderately preferential distribution of the active epothilone to FR overexpressing 98M109 tumors,thereby supporting targeted delivery of cytotoxics through the folate receptor.展开更多
In the present study, total membrane proteins from tumor cell lines including HepG2, Hep3 B2,H226, Ovcar3 and N87 were extracted and digested with γLys C and trypsin. The resulting peptide lysate were pre-fractionate...In the present study, total membrane proteins from tumor cell lines including HepG2, Hep3 B2,H226, Ovcar3 and N87 were extracted and digested with γLys C and trypsin. The resulting peptide lysate were pre-fractionated and subjected to untargeted quantitative proteomics analysis using a high resolution mass spectrometer. The mass spectra were processed by the Max Quant and the protein abundances were estimated using total peak area(TPA) method. A total of 6037 proteins were identified, and the analysis resulted in the identification of 2647 membrane proteins. Of those, tumor antigens and absorption,metabolism, disposition and elimination(ADME) proteins including UDP-glucuronosyltransferase,cytochrome P450, solute carriers and ATP-binding cassette transporters were detected and disclosed significant variations among the cell lines. The principal component analysis was performed for the cluster of cell lines. The results demonstrated that H226 is closely related with N87, while Hep3 B2 aligned with HepG2. The protein cluster of Ovcar3 was apart from that of other cell lines investigated. By providing for the first time quantitative untargeted proteomics analysis, the results delineated the expression profiles of membrane proteins. These findings provided a useful resource for selecting targets of choice for anticancer therapy through advancing data obtained from preclinical tumor cell line models to clinical outcomes.展开更多
文摘Compared to their linear counterparts,cyclic peptides show better biological activities,such as antibacterial,immunosuppressive,and anti-tumor activities,and pharmaceutical properties due to their conformational rigidity.However,cyclic peptides could form numerous putative metabolites from potential hydrolytic cleavages and their fragments are very difficult to interpret.These characteristics pose a great challenge when analyzing metabolites of cyclic peptides by mass spectrometry.This study was to assess and apply a software-aided analytical workflow for the detection and structural characterization of cyclic peptide metabolites.Insulin and atrial natriuretic peptide(ANP)as model cyclic peptides were incubated with trypsin/chymotrypsin and/or rat liver S9,followed by data acquisition using TripleTOF?5600.Resultant full-scan MS and MS/MS datasets were automatically processed through a combination of targeted and untargeted peak finding strategies.MS/MS spectra of predicted metabolites were interrogated against putative metabolite sequences,in light of a,b,y and internal fragment series.The resulting fragment assignments led to the confirmation and ranking of the metabolite sequences and identification of metabolic modification.As a result,29 metabolites with linear or cyclic structures were detected in the insulin incubation with the hydrolytic enzymes.Sequences of twenty insulin metabolites were further determined,which were consistent with the hydrolytic sites of these enzymes.In the same manner,multiple metabolites of insulin and ANP formed in rat liver S9 incubation were detected and structurally characterized,some of which have not been previously reported.The results demonstrated the utility of software-aided data processing tool in detection and identification of cyclic peptide metabolites.
文摘To assess targeting of an epothilone folate conjugate(BMS-753493) to the folate receptor(FR)-overexpressed tumor in mice bearing both FRt and FR– tumors,a series of experiments were conducted by quantitative whole-body autoradiography(QWBA) and LC–MS/MS following i.v.administration of BMS-753493 or its active moiety,BMS-748285 in mice bearing FRt(98M109) and FR–(M109) tumors.QWBA showed [3H]BMS-753493–derived radioactivity was extensively distributed to various tissues.The FR over-expressing 98M109 tumors showed consistently higher level of radioactivity than FR-negative tumors(i.e.,M109 tumors) up to 48 h post dose of [3H]BMS-753493,despite the magnitude of difference between the tumors is relatively small(generally 3 5-fold).The radioactivity level in 98M109 tumors was 2 12-fold of normal tissues except intestine/content at 48 h post dose.No selective radioactivity uptake into 98M109 tumors over M109 or normal tissues was observed after i.v.administration of the active epothilone,[3H]BMS-748285.LC–MS/MS measurements demonstrated that the concentrations of BMS-748285,presumably from hydrolysis of the folate conjugate,in 98M109 tumors were greater than those in M109 tumors after i.v.administration of BMS-753493(2–3-fold) whereas no differential uptake in the tumors following BMS-748285 administration.Those data were consistent with radioactivity determinations.Those results demonstrated that the folate conjugation in BMS-753493 enabled moderately preferential distribution of the active epothilone to FR overexpressing 98M109 tumors,thereby supporting targeted delivery of cytotoxics through the folate receptor.
文摘In the present study, total membrane proteins from tumor cell lines including HepG2, Hep3 B2,H226, Ovcar3 and N87 were extracted and digested with γLys C and trypsin. The resulting peptide lysate were pre-fractionated and subjected to untargeted quantitative proteomics analysis using a high resolution mass spectrometer. The mass spectra were processed by the Max Quant and the protein abundances were estimated using total peak area(TPA) method. A total of 6037 proteins were identified, and the analysis resulted in the identification of 2647 membrane proteins. Of those, tumor antigens and absorption,metabolism, disposition and elimination(ADME) proteins including UDP-glucuronosyltransferase,cytochrome P450, solute carriers and ATP-binding cassette transporters were detected and disclosed significant variations among the cell lines. The principal component analysis was performed for the cluster of cell lines. The results demonstrated that H226 is closely related with N87, while Hep3 B2 aligned with HepG2. The protein cluster of Ovcar3 was apart from that of other cell lines investigated. By providing for the first time quantitative untargeted proteomics analysis, the results delineated the expression profiles of membrane proteins. These findings provided a useful resource for selecting targets of choice for anticancer therapy through advancing data obtained from preclinical tumor cell line models to clinical outcomes.
