Noriko Iwamoto

High-resolution imaging mass spectrometry reveals detailed spatial distribution of phosphatidylinositols in human breast cancer.

High‐resolution matrix‐assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) is an emerging application for lipid research that provides a comprehensive and detailed spatial distribution of ionized molecules. Recent lipidomic approach has identified several phospholipids and phosphatidylinositols (PIs) are accumulated in breast cancer tissues and are therefore novel biomarker candidates. Because their distribution and significance remain unclear, we investigated the precise spatial distribution of PIs in human breast cancer tissues using high‐resolution MALDI IMS. We evaluated tissues from nine human breast cancers and one normal mammary gland by negative ion MALDI IMS at a resolution of 10 μm. We detected 10 PIs with different fatty acid compositions, and their proportions were remarkably variable in the malignant epithelial regions. High‐resolution imaging enabled us to discriminate cancer cell clusters from the adjacent stromal tissue within epithelial regions; moreover, this technique revealed that several PIs were specifically localized to cancer cell clusters. These PIs were heterogeneously distributed within cancer cell clusters, allowing us to identify two different populations of cancer cells that predominantly expressed either PI(18:0/18:1) or PI(18:0/20:3). Tracing the expression level of PIs during cancer cell progression suggested that the latter population is associated with the invasion. Our study documents a novel model for phospholipid analysis of breast cancer tissues by using high‐resolution MALDI IMS and identifies candidate PIs that can describe a specific phenotype of cancer cells.

Fully validated LCMS bioanalysis of Bevacizumab in human plasma using nano-surface and molecular-orientation limited (nSMOL) proteolysis

The chemistry of nano-surface and molecular-orientation limited (nSMOL) proteolysis is the Fab-selective limited proteolysis by making use the difference of protease nanoparticle diameter (200 nm) and antibody resin pore diameter (100 nm). In this report, we have demonstrated that the full validation for Bevacizumab bioanalysis in human plasma using nSMOL. The immunoglobulin fraction was collected by Protein A resin from plasma, then nSMOL reaction was performed using the FG nanoparticle-immobilized trypsin under the nondenaturing physiological condition at 50 °C for 6 h. After removal of resin and nanoparticles, the signature peptide of Bevacizumab complementarity-determining region (CDR) and internal standard P14R were simultaneously quantified by LCMS multiple reaction monitoring (MRM). This nSMOL method quantification of Bevacizumab showed sensitivity of 0.146 μg/ml and linearity of 0.146-300 μg/ml. The intra- and inter-assay precision of lower limit of quantification (LLOQ), low quality control (LQC), middle quality control (MQC), and high quality control (HQC) was 7.94-15.2% and 14.6%, 7.15-13.5% and 11.7%, 2.63-6.47% and 5.83%, and 3.09-4.35% and 4.45%, respectively. These results indicate that nSMOL is also significant method for Bevacizumab bioanalysis in human plasma.

Validated LC-MS/MS analysis of immune checkpoint inhibitor Nivolumab in human plasma using a Fab peptide-selective quantitation method: nano-surface and molecular-orientation limited (nSMOL) proteolysis.

We previously reported the nano-surface and molecular-orientation limited (nSMOL) proteolysis, which is a novel method for selective quantitation of monoclonal antibody Fab. The nSMOL strategy is a Fab-selective limited proteolysis which utilizes the size difference between the protease nanoparticle (200nm) and the antibody resin pore (100nm). Here, we applied this method to a fully validated LCMS analysis of Nivolumab in human plasma. The immunoglobulin fraction was collected using Protein A resin, which was then followed by nSMOL reaction using the FG nanoparticle surface-immobilized trypsin under a nondenaturing physiological condition at 50°C for 7h. After removal of resin and nanoparticles by filter centrifugation, signature peptides were separated using the ODS column liquid chromatography. The signature peptide ASGITFSNSGMHWVR from Nivolumab complementarity-determining region (CDR) and the P14R internal standard were simultaneously quantified by multiple-reaction monitoring (MRM) LCMS, with parent m/z 550.8>fragment m/z 661.5 (y11 2+). The lower limit of quantification (LLOQ) of Nivolumab using the nSMOL method was 0.977μg/ml, with a linear dynamic range of from 0.977 to 250μg/ml. The intra- and inter-assay precision of LLOQ, low quality control (LQC), middle quality control (MQC), and high quality control (HQC) were 7.56-17.9% and 15.6%, 6.99-9.25% and 7.51%, 2.51-8.85% and 8.01%, and 4.78-7.33% and 6.75%, respectively. Our study demonstrates that the nSMOL bioanalysis can be utilized as a reliable method for clinical pharmacokinetic studies of Nivolumab and other antibody drugs.

LC–MS bioanalysis of Trastuzumab and released emtansine using nano-surface and molecular-orientation limited (nSMOL) proteolysis and liquid–liquid partition in plasma of Trastuzumab emtansine-treated breast cancer patients

Graphical abstract Figure. No Caption available. Abstract Antibody‐drug conjugates (ADCs) consist of monoclonal antibody and cytotoxic drugs covalently attached via stable crosslinkers, and are prospective antibody drugs for cancer therapy. To cover the overall pharmacokinetic understanding of ADCs, both the antibody and the released drugs are necessary for practical clinical observation. The nano‐surface and molecular‐orientation limited (nSMOL) proteolysis is a universal approach for antibody bioanalysis that enable Fab‐selective proteolysis, which maintains antibody sequence specificity while decreasing excess analyte peptides. In this study, we describe quantitative assays for ADC in human plasma using nSMOL for the antibody and polarity‐selective liquid–liquid partition with a methanol/ethyl acetate mixed solvent for the cytotoxic drugs. This approach led to the successful development of LC–MS validated bioanalysis of the antibody and released drugs within 20% for lower limit of quantitation and 15% for another concentration setting of Trastuzumab emtansine (T‐DM1), Trastuzumab antibody and emtansine conjugated with crosslinker (DM1‐MCC). The validated concentration ranges in human plasma were 0.06–250 &mgr;g/mL for T‐DM1 and 0.39–200 ng/mL for DM1‐MCC. These results indicate that LC–MS method with a two‐sided approach, using nSMOL and liquid–liquid partition, show potential for the precise pharmacokinetic study for ADC development and treatment.

Antibody drug quantitation in coexistence with anti-drug antibodies on nSMOL bioanalysis

Therapeutic monoclonal antibodies (mAbs) are developed for treatment of diverse cancers and autoimmune diseases. For expansion of mAbs approval against unapproved diseases and pharmaceutical development, pharmacokinetics study is very important. Bioanalysis provides one of the most essential index against pharmacokinetics information. So far, we developed useful method for bioanalysis of mAbs in plasma or serum, nSMOL: nano-surface and molecular-orientation limited proteolysis. This method can provide accurate and reproducible value of mAbs content in plasma. Quantification of mAbs using ELISA is strongly influenced by endogenous ligand or anti-drug antibodies. In this report, we exhibited the role of nSMOL proteolysis coupled to LC-MS/MS analysis against quantification of mAbs bound to some binding molecules. The ligands against mAbs do not affect quantification of mAbs concentration in plasma using nSMOL proteolysis. On the other hands, some anti-drug antibodies (ADA), such as idiotypic antibodies, inhibit quantification of mAbs using nSMOL proteolysis. Acid dissociation has some efficacy in accurate value of quantitation of ADA binding mAbs using nSMOL proteolysis coupled to LC-MS/MS analysis. Accordingly, we consider that nSMOL method will contribute to understanding of mAb PK data and therapeutic reference combining with ADA measurements.

Multiplex LCMS Bioanalysis of Brentuximab Vedotin, Rituximab and Cetuximab towards Therapeutic Drug Monitoring Application by Combined Calibration Curve Using Fab-Selective Limited Proteolysis nSMOL

Background: Recently, monoclonal antibody (mAb) bioanalysis using mass spectrometry has begun to be recognized as useful technology for mAbs measurement other than ELISA. We have recently exploited a high-precision method for bioanalysis of monoclonal antibody (mAb) using mass spectrometry. The method is nano-surface and molecular-orientation limited (nSMOL) proteolysis, which is useful for LCMS bioanalysis of many kinds of antibody drugs. Methods: nSMOL is Fab-selective limited proteolysis which consists of the difference of protease nanoparticle diameter (200 nm) and antibody resin pore diameter (100 nm). For limited proteolysis of antibody, Protein A resin (pore: 100 nm) slurry was added to plasma including monoclonal antibody, and the antibody Fc region was immobilized to the resin at 25°C for 10 min with gentle vortexing. Antibody-immobilized resin was washed with PBS, and limited proteolysis was performed with trypsin-conjugated FG beads (diameter: 200 nm). Limited proteolysis of Fab region on antibody was achieved by these two diameter difference. After nSMOL proteolysis, the generated peptides were collected by only simple filtration. Results: In this study, we have demonstrated that the first full validation dataset for bioanalysis using nSMOL of antibody-drug conjugate (ADC), Brentuximab vedotin, in human plasma using nSMOL proteolysis. Full validation using nSMOL proteolysis fulfilled criteria of guideline on bioanalytical method validation in pharmaceutical development for small molecule drug compounds. Conclusions: These results indicate that nSMOL is also significant method for precise quantification of ADC in plasma, such as Brentuximab vedotin. Furthermore, we report that nSMOL proteolysis is able to apply for not only single-analyte but also multi-analyte bioanalysis of each mAbs in plasma, so that, nSMOL proteolysis is feasible multiplex bioanalysis for many clinical pharmacokinetic study and therapeutic drug monitoring.

Validated LC/MS bioanalysis of Rituximab CDR peptides using nano-surface and molecular-orientation limited (nSMOL) proteolysis

Presently, monoclonal antibodies (mAbs) therapeutics have big global sales and are starting to receive competition from biosimilars. We previously reported that the nano-surface and molecular-orientation limited (nSMOL) proteolysis which is optimal method for bioanalysis of antibody drugs in plasma. The nSMOL is a Fab-selective limited proteolysis, which utilize the difference of protease nanoparticle diameter (200 nm) and antibody resin pore diameter (100 nm). In this report, we have demonstrated that the full validation for chimeric antibody Rituximab bioanalysis in human plasma using nSMOL proteolysis. The immunoglobulin fraction was collected using Protein A resin from plasma, which was then followed by the nSMOL proteolysis using the FG nanoparticle-immobilized trypsin under a nondenaturing condition at 50°C for 6 h. After removal of resin and nanoparticles, Rituximab signature peptides (GLEWIGAIYPGNGDTSYNQK, ASGYTFTSYNMHWVK, and FSGSGSGTSYSLTISR) including complementarity-determining region (CDR) and internal standard P14R were simultaneously quantified by multiple reaction monitoring (MRM). This quantification of Rituximab using nSMOL proteolysis showed lower limit of quantification (LLOQ) of 0.586 µg/mL and linearity of 0.586 to 300 µg/mL. The intra- and inter-assay precision of LLOQ, low quality control (LQC), middle quality control (MQC), and high quality control (HQC) was 5.45-12.9% and 11.8, 5.77-8.84% and 9.22, 2.58-6.39 and 6.48%, and 2.69-7.29 and 4.77%, respectively. These results indicate that nSMOL can be applied to clinical pharmacokinetics study of Rituximab, based on the precise analysis.

Application of nano-surface and molecular-orientation limited proteolysis to LC–MS bioanalysis of cetuximab

BACKGROUND We recently reported the principle of nano-surface and molecular-orientation limited (nSMOL) proteolysis, which is useful for LC-MS bioanalysis of antibody drugs. METHODOLOGY The nSMOL is a Fab-selective limited proteolysis which utilizes the difference of protease-immobilized nanoparticle diameter (200 nm) and antibody collection resin pore (100 nm). We have demonstrated the full validation for chimeric antibody cetuximab bioanalysis in human plasma using nSMOL. Signature peptides (SQVFFK, ASQSIGTNIHWYQQR and YASESISGIPSR) in cetuximab complementarity-determining region were simultaneously quantitated by LC-MS multiple reaction monitoring. CONCLUSION This nSMOL quantification showed sensitivity of 0.586 µg/ml and linearity of 0.586 to 300 µg/ml. Full validation study archived the guideline criteria of low Mw drug compounds. These results indicate that nSMOL is also significant method for cetuximab bioanalysis.

Recent advances in mass spectrometry-based approaches for proteomics and biologics: Great contribution for developing therapeutic antibodies

Since the turn of the century, mass spectrometry (MS) technologies have continued to improve dramatically, and advanced strategies that were impossible a decade ago are increasingly becoming available. The basic characteristics behind these advancements are MS resolution, quantitative accuracy, and information science for appropriate data processing. The spectral data from MS contain various types of information. The benefits of improving the resolution of MS data include accurate molecular structural-derived information, and as a result, we can obtain a refined biomolecular structure determination in a sequential and large-scale manner. Moreover, in MS data, not only accurate structural information but also the generated ion amount plays an important rule. This progress has greatly contributed a research field that captures biological events as a system by comprehensively tracing the various changes in biomolecular dynamics. The sequential changes of proteome expression in biological pathways are very essential, and the amounts of the changes often directly become the targets of drug discovery or indicators of clinical efficacy. To take this proteomic approach, it is necessary to separate the individual MS spectra derived from each biomolecule in the complexed biological samples. MS itself is not so infinite to perform the all peak separation, and we should consider improving the methods for sample processing and purification to make them suitable for injection into MS. The above-described characteristics can only be achieved using MS with any analytical instrument. Moreover, MS is expected to be applied and expand into many fields, not only basic life sciences but also forensic medicine, plant sciences, materials, and natural products. In this review, we focus on the technical fundamentals and future aspects of the strategies for accurate structural identification, structure-indicated quantitation, and on the challenges for pharmacokinetics of high-molecular-weight protein biopharmaceuticals.

Application of nSMOL coupled with LC‐MS bioanalysis for monitoring the Fc‐fusion biopharmaceuticals Etanercept and Abatacept in human serum

The principle of nano‐surface and molecular‐orientation limited (nSMOL) proteolysis has a unique characteristic Fab‐selective proteolysis for antibody bioanalysis that is independent of a variety of monoclonal antibodies by the binding antibody Fc via Protein A/G in a pore with 100 nm diameter and modified trypsin immobilization on the surface of nanoparticles with 200 nm diameter. Since minimizing peptide complexity and protease contamination while maintaining antibody sequence specificity enables a rapid and broad development of optimized methods for liquid chromatography‐mass spectrometry (LC‐MS) bioanalysis, the application of regulatory LC‐MS for monitoring antibody biopharmaceuticals is expected. nSMOL is theoretically anticipated to be applicable for representative Fc‐fusion biopharmaceuticals, because Protein A/G‐binding site Fc exists on the C‐terminus, and its functional domain is available to orient and interact with the reaction solution. In this report, we describe the validated LC‐MS bioanalysis for monitoring Ethanercept and Abatacept using nSMOL technology. The quantitation range of Ethanercept in human serum was from 0.195 to 100 μg/mL using the signature peptide VFCTK (aa.43‐47), and that of Abatacept was from 0.391 to 100 μg/mL using the signature peptide MHVAQPAVVLASSR (aa.1‐14). Both proteins fulfilled the guideline criteria for low‐molecular‐weight drug compounds. The results indicate that the clinical and therapeutic monitoring for antibody and Fc‐fusion biopharmaceuticals are adequately applicable using nSMOL proteolysis coupled with LC‐MS bioanalysis.