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AIMS: Mirvetuximab soravtansine is a first-in-class antibody-drug conjugate recently approved for the treatment of folate receptor-α positive ovarian cancer. The aim of this study was to develop a population pharmacokinetic model to describe the concentration-time profiles of mirvetuximab soravtansine, the payload (DM4) and a metabolite (S-methyl-DM4). METHODS: Mirvetuximab soravtansine was administered intravenously from 0.15 to 7 mg/kg to 543 patients with predominantly platinum-resistant ovarian cancer in 3 clinical studies, and the plasma drug concentrations were analysed using a nonlinear mixed-effects modelling approach. Stepwise covariate modelling was performed to identify covariates. RESULTS: We developed a semi-mechanistic population pharmacokinetic model that included linear and nonlinear routes for the elimination of mirvetuximab soravtansine and a target compartment for the formation and disposition of the payload and metabolite in tumour cells. The clearance and volume of the central compartment were 0.0153 L/h and 2.63 L for mirvetuximab soravtansine, 8.83 L/h and 3.67 L for DM4, and 2.04 L/h and 6.3 L for S-methyl-DM4, respectively. Body weight, serum albumin and age were identified as statistically significant covariates. Exposures in patients with renal or hepatic impairment and who used concomitant cytochrome P450 (CYP) 3A4 inhibitors were estimated. CONCLUSION: There is no need for dose adjustment due to covariate effects for mirvetuximab soravtansine administered at the recommended dose of 6 mg/kg based on adjusted ideal body weight. Dose adjustment is not required for patients with mild or moderate renal impairment, mild hepatic impairment, or when concomitant weak and moderate CYP3A4 inhibitors are used.
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Anticuerpos Monoclonales Humanizados , Inmunoconjugados , Maitansina , Neoplasias Ováricas , Humanos , Femenino , Resistencia a Antineoplásicos , Neoplasias Ováricas/tratamiento farmacológico , Inmunoconjugados/efectos adversos , Ácido Fólico/farmacología , Ácido Fólico/uso terapéutico , Maitansina/análogos & derivadosRESUMEN
The fragmentation of protonated molecules (MH(+)) in mass spectrometry usually results in even-electron product ions, but the MH(+) ions of sulfonamides are different as they often produce dominant radical cations of the constituent amines. For a series of benzenesulfonamides of anilines that bear various substituents, we found that the sulfonamides are preferentially protonated at the nitrogen, which is different from the carboxylic amides. Upon N-protonation, the S-N bond dissociates spontaneously to produce an intermediate [sulfonyl cation/aniline] complex. Within the ion-neutral complex, charge transfer between the two partners occurs in the gas phase to give rise to the ionized anilines. A substantial energy barrier was found to govern the reaction, which is consistent with the outer-sphere electron transfer mechanism. This energy barrier prevents the charge transfer when a strong electron-withdrawing substituent is attached to the aniline moiety. In contrast, when the aniline bears an electron-donating group, charge transfer is still more favorable than the dissociation of the intermediate ion-neutral complex, in spite of the existence of the energy barrier, and therefore dominates. A correlation was observed between the intensities of the ionized anilines and the ionization energies of these anilines.
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Protones , Teoría Cuántica , Sulfonamidas/química , Gases , Espectrometría de Masas , Estructura Molecular , Transición de FaseRESUMEN
An intramolecular transacylation reaction was observed in the mass spectrometry of molecules containing both benzoyl and carboxymethyl groups on an aromatic heterocyclic core. The reaction is triggered by a dissociative protonation on the heterocyclic ring at the atom (carbon or nitrogen) that bonds to the benzoyl group, leading to an intermediate ion-neutral complex. The incipient benzoyl cation in the complex migrates to attack the carboxyl group of the neutral partner at the carbonyl or hydroxyl oxygen under thermodynamic or kinetic control, respectively. Elimination of benzoic acid followed by loss of carbon monoxide takes place as a result of the transacylation.
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Hidrocarburos Aromáticos/química , Iones/química , Espectrometría de Masas/métodos , Acilación , ProtonesRESUMEN
OBJECTIVE The objective of this study was to characterize the neurotransmitter systems that cause constriction of murine airways. METHODS Murine precision cut lung slices (PCLS) and trachea were prepared, placed into perfusion chambers equipped with platinum electrodes and stimulated transmurally (1.0 ms, 50 V, 0.1- 30 Hz). To measure PCLS constriction, changes in airway luminal area in response to electric field stimulation (EFS) were captured as video images quantified using Image J software. For trachea, changes in isometric tension were recorded using Grass force transducers. Frequency response curves were generated in the absence and the presence of the inhibitors magnesium, atropine and capsaicin and responses analyzed and compared using a student' s t- test (P<0.05). RESULTS EFS caused airway constriction in a frequency-dependent manner that was best fit by a biphasic curve. Neuron-specific stimulation was verified by Mg2+ blockade. Maximum airway constriction to 30 Hz EFS in PCLS was (51.8±3.0)% while tracheal constriction averaged (551±80)mg. Interestingly, in PCLS the muscarinic receptor antagonist atropine (10 μmol · L- 1) blocked (99.5 ± 7.2)% of EFS induced constriction at 1 Hz, but only blocked (23.3±3.8)% of EFS induced constriction at 30 Hz and eliminated the first phase but not the second phase of the biphasic EFS response. Treatment with capsaicin to deplete sensory neurotransmitters significantly increased EFS constriction supporting the presence of sensory neurotransmitter systems in airways. CONCLUSION These data are consistent with parasympathetic constriction of airways by acetylcholine at lower EFS frequencies while higher frequencies release sensory dilator neurotransmitters. These data provide evidence for multiple nerve types innervating airways which may provide novel targets for treatment of lung disease.
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OBJECTIVE TNF- related apoptosis- inducing ligand(TRAIL)is a promising cancer therapeutic agent due to its minimal toxicity to normal tissues and remarkable apoptotic activity in tumors. However, most breast cancer cells are resistant to TRAIL- induced apoptosis. Our objectives are to investigate the underlying molecular mechanisms and to develop strategies to overcome such resistance. METHODS To identify modulators of TRAIL-induced apoptosis, we carried out a genome wide siRNA screen. To validate the screening result, we either silenced or overexpressed the identified genes in various breast cancer cells and changes in growth and TRAIL-induced cell apoptosis were determined in vitro and in an orthotopic xenograft mouse model. Finally, we investigated whether small molecules targeting the identified genes improve the effectiveness of TRAIL-therapy. RESULTS We unexpectedly identified androgen receptor (AR) to be responsible for TRAIL resistance. While AR is classically viewed as the key factor in prostate cancer progression, we found that AR expression levels were markedly elevated in human invasive breast cancer specimens including triple- negative breast cancers (TNBC) that are highly aggressive with poor prognosis. Importantly, breast cancer cell lines express different levels of AR that correlated with their TRAIL resistance. AR overexpression in MDA- MB- 231 and MDA- MB- 436 cells suppressed the TRAIL sensitivity whereas knockdown of AR rendered MCF-7 and MDA-MB-453 cells sensitive to TRAIL-induced apoptosis. AR overexpression also induced TRAIL resistance in breast tumors in vivo. Further, we observed an upregulation of the TRAIL receptor, death receptor 5 (DR5) in breast cancer cells, following the removal or inhibition of AR by its antagonists Casodex and MDV3100. Treatment with AR antagonists also enhanced TRAIL- induced breast cancer cell apoptosis. CONCLUSION AR signaling suppresses TRAIL-induced breast cancer cell apoptosis, in part, by suppressing DR5 expression, and a combination of AR antagonists together with TRAIL may be a novel and effective therapy for TNBC.
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In mass spectrometry of the alpha,beta-unsaturated aromatic ketones, Ph-CO-CH=CH-Ph', losses of a benzene from the two ends and elimination of a styrene are the three major fragmentation reactions of the protonated molecules. When the ketones are substituted on the right phenyl ring, the electron-donating groups are in favor of losing a styrene to form the benzoyl cation, PhCO(+), whereas the electron-withdrawing groups strongly favor loss of benzene of the left side to form a cinnamoyl cation, Ph'CH=CHCO(+). When the ketones are substituted on the left phenyl ring, the substituent effects on the reactions are reversed. In both cases, the ratios of the two competitive product ions are well-correlated with the sigma p(+) substituent constants. Theoretical calculations indicate that the carbonyl oxygen is the most favorable site for protonation, and the olefinic carbon adjacent to the carbonyl is also favorable especially when a strong electron-releasing group is present on the right phenyl ring. The energy barrier to the interconversion between the ions formed from protonation at these two sites regulates the overall reactions. Transfer of a proton from the carbonyl oxygen to the ipso position on either phenyl ring, which is dissociative, triggers loss of benzene.
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Cetonas/química , Protones , Espectrometría de Masas , Modelos Moleculares , Estructura MolecularRESUMEN
Polarity switching mass spectrometry is an efficient way to collect structural data on drug metabolites. The value of this approach is illustrated with the in vitro metabolism of RO9237. Metabolites are identified by positive and negative electrospray ionization (ESI) full scan mass spectrometry, MS/MS and MS(3) using unlabelled and (14)C-radiolabelled versions of the drug. Comparison of the relative detectability of these metabolites by +ESI and -ESI shows that neither ESI mode is universal. It is advantageous to screen for metabolites using both positive and negative ionization modes. This is especially true for phase II metabolism which tends to make molecules more polar and often more acidic. Identification of phase II metabolites also benefits greatly from MS(3) experiments because the conjugating groups typically are cleaved in MS/MS and information on the core structure is only obtained in MS(3). A special case of phase II metabolism is the generation of glutathione (GSH) conjugates from reactive metabolites. The detection of GSH conjugates also benefits from generating both positive and negative ESI mass spectral data.
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Antagonistas de la Serotonina/farmacocinética , Sulfonas/farmacocinética , Animales , Biotransformación , Cromatografía Líquida de Alta Presión , Haplorrinos , Hepatocitos/metabolismo , Humanos , Indicadores y Reactivos , Microsomas Hepáticos/metabolismo , Receptores de Serotonina/efectos de los fármacos , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
It is often found in mass spectrometry that when a molecule is protonated at the thermodynamically most favorable site, no fragmentation occurs, but a major reaction is observed when the proton migrates to a different position. For benzophenones, acetophenones, and dibenzyl ether, which are all preferentially protonated at the oxygen, deacylation or dealkylation was observed in the collision-induced dissociation of the protonated molecules. For para-monosubstituted benzophenones, electron-withdrawing substituents favor the formation of RC6H4CO+ (R = substituent), whereas electron-releasing groups favor the competing reaction leading to C6H5CO+. The ln[(RC6H4CO+)/(C6H5CO+)] values are well-correlated with the sigmap+ substituent constants. In the fragmentation of protonated acetophenones, deacetylation proceeds to give an intermediate proton-bound dimeric complex of ketene and benzene. The distribution of the product ions was found to depend on the proton affinities of ketene and substituted benzenes, and the kinetic method was applied in identifying the reaction intermediate. Protonated dibenzyl ether loses formaldehyde upon dealkylation, via an ion-neutral complex of the benzyloxymethyl cation and neutral benzene. These gas-phase retro-Friedel-Crafts reactions occurred as a result of the attack of the proton at the carbon atom to which the carbonyl or the methylene group is attached on the aromatic ring, which is described as the dissociative protonation site.
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Acetofenonas/química , Benzofenonas/química , Éteres Fenílicos/química , Protones , Espectrometría de Masa por Ionización de Electrospray , Electrones , Modelos Químicos , Estructura MolecularRESUMEN
In electrospray ionization (ESI) on a triple quadrupole mass spectrometer, benzydamine, a molecule with an N,N-dimethylaminopropoxyl side chain, showed a fragmentation pattern in Q1 scans that is dramatically different from the mass-selected collision-induced dissociation (CID) of its MH(+) ion. The N,N-dimethylimmonium ion, which dominates in Q1 scans at higher energies, is only a minor product in all CID spectra. By using a smaller model molecule, N,N,N',N'-tetramethyl-1,3-propanediamine, with the kinetic energy release measured for the corresponding reaction, we have demonstrated that an ion-neutral complex composed of the N,N-dimethylazetidine cation and a neutral counterpart is involved. When the ion-neutral complex intermediate evolves toward elimination to form the immonium ion, the transition state is stabilized by the neutral species. Solvation of the ion-neutral complex, which obstructs the separation of the two partners by the resulting tighter enclosure, facilitates the elimination by enhancing the stabilization of the transition state. Therefore, the prevalence of the immonium ion in Q1 scans was a result of solvation in the ESI source. In CID reactions, where the decomposing ions are mass-selected and thus solvation does not exist, the immonium ion was a minor product, and the separation of the ion-neutral complex became dominant.