Quality control and stability studies with the monoclonal antibody, trastuzumab: application of 1D- vs. 2D-gel electrophoresis

Trastuzumab-Mediated Cardiotoxicity and Its Preventive Intervention by Zingerone through Antioxidant and Inflammatory Pathway in Rats

Trastuzumab (TZB) is a new medicine, used to treat cancers of the breast and stomach. However, the cardiotoxic potential of this drug edges out its clinical advantages. The present study was designed to find out the effect of zingerone against trastuzumab-mediated cardiotoxicity in rats. In this study, five groups of rats with eight animals in each group were used. Group 1 was treated with normal saline, as a normal control (NC); Group 2 was treated with TZB (6 mg/kg/week-for five weeks) intraperitoneally as a toxic control. Groups 3 and 4 were pre-treated with zingerone (50 and 100 mg/kg, as per their body weight orally) along with five doses of TZB for five weeks, and Group 5 was treated with zingerone (100 mg/kg, body weight orally) as a control. TZB treatment showed cardiotoxicity as evidenced by increased levels of aspartate aminotransferase (AST), creatine kinase-myocardial band (CK-MB), lactate dehydrogenase (LDH), and lipid peroxidation (LPO) and decreased level of glutathione (GSH), and antioxidant enzymes such as glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-s- transferase (GST), catalase (CAT), and superoxide dismutase (SOD) activities. Zingerone pre-treatment significantly decreased the levels of AST, CK-MB, LDH, and LPO and increased GSH and antioxidant enzymes content toward their normal level. In the TZB-alone administered group, inflammatory cytokines (IL-2 and TNF-α) levels were also elevated. Pre-treatment with zingerone restored the level of IL-2 and TNF-α toward normal level. The current findings undoubtedly demonstrated zingerone's cardioprotective nature against TZB-mediated cardiotoxicity in rats with the evidence of histopathological recall.

Obtaining Highly Active Catalytic Antibodies Capable of Enzymatically Cleaving Antigens

A catalytic antibody has multiple functions compared with a monoclonal antibody because it possesses unique features to digest antigens enzymatically. Therefore, many catalytic antibodies, including their subunits, have been produced since 1989. The catalytic activities often depend on the preparation methods and conditions. In order to elicit the high catalytic activity of the antibodies, the most preferable methods and conditions, which can be generally applicable, must be explored. Based on this view, systematic experiments using two catalytic antibody light chains, #7TR and H34, were performed by varying the purification methods, pH, and chemical reagents. The experimental results obtained by peptidase activity tests and kinetic analysis, revealed that the light chain's high catalytic activity was observed when it was prepared under a basic condition. These data imply that a small structural modulation of the catalytic antibody occurs during the purification process to increase the catalytic activity while the antigen recognition ability is kept constant. The presence of NaCl enhanced the catalytic activity. When the catalytic light chain was prepared with these preferable conditions, #7TR and H34 hugely enhanced the degradation ability of Amyloid-beta and PD-1 peptide, respectively.

Could allicin alleviate trastuzumab-induced cardiotoxicity in a rat model through antioxidant, anti-inflammatory, and antihyperlipidemic properties?

AIMS

Although trastuzumab (TZB)-induced cardiotoxicity is well documented and allicin (one of the main active garlic ingredients) has ameliorating effects against numerous causes of toxicities; however, the influence of allicin on TZB-induced cardiotoxicity has not been investigated yet. Therefore, the current work explored the potential cardioprotective structural, biochemical, and molecular mechanisms of allicin against TZB-induced cardiotoxicity in a rat's model.

METHODS

Forty rats were divided into four equal groups and treated for five weeks. The control group (G1) received PBS, the allicin group (G2) received allicin (9 mg/kg/day), the TZB group (G3) received TZB (6 mg/kg/week), and the allicin+TZB group (G4) received 9 mg of allicin/kg/day +6 mg of TZB/kg/week. Heart specimens and blood samples were processed for histopathological, immunohistochemical, biochemical, and molecular investigations to determine the extent of cardiac injury in all groups.

KEY FINDINGS

The myocardium of G3 revealed significant increases in the numbers of inflammatory and apoptotic cells and the area percentage of collagen fibers and TNF-α immunoexpression compared with G1 and G2. Besides, qRT-PCR analysis exhibited significant reductions of SOD3, GPX1, and CAT expressions with significant increases in TNFα, IL-1β, IL-6, cTnI, cTnT, and LDH expressions. Additionally, flow cytometry analysis demonstrated a significant elevation in the apoptotic and ROS levels. In contrast, allicin+TZB cotherapy in G4 ameliorated all previous changes compared with G3.

SIGNIFICANCE

The current study proves that allicin could be used as a novel supplementary cardioprotective therapy to avoid TZB-induced cardiotoxicity via its anti-inflammatory, antifibrotic, antioxidant, antihyperlipidemic, and antiapoptotic properties.

Nanosystem functionalization strategies for prostate cancer treatment: a review

Prostate cancer (PC) has a high morbidity and mortality rate worldwide, and the current clinical guidelines can vary depending on the stage of the disease. Drug delivery nanosystems (DDNs) can improve biopharmaceutical properties of encapsulated anti-cancer drugs by modulating their release kinetics, improving physicochemical stability and reducing toxicity. DDN can also enhance the ability of specific targeting through surface modification by coupling ligands (antibodies, nucleic acids, peptides, aptamer, proteins), thus favouring the cell internalisation process by endocytosis. The purposes of this review are to describe the limitations in the treatment of PC, explore different functionalization such as polymeric, lipid and inorganic nanosystems aimed at the treatment of PC, and demonstrate the improvement of this modification for an active target, as alternative and promising candidates for new therapies.

What Room for Two-Dimensional Gel-Based Proteomics in a Shotgun Proteomics World?

Two-dimensional gel electrophoresis was instrumental in the birth of proteomics in the late 1980s. However, it is now often considered as an outdated technique for proteomics—a thing of the past. Although this opinion may be true for some biological questions, e.g., when analysis depth is of critical importance, for many others, two-dimensional gel electrophoresis-based proteomics still has a lot to offer. This is because of its robustness, its ability to separate proteoforms, and its easy interface with many powerful biochemistry techniques (including western blotting). This paper reviews where and why two-dimensional gel electrophoresis-based proteomics can still be profitably used. It emerges that, rather than being a thing of the past, two-dimensional gel electrophoresis-based proteomics is still highly valuable for many studies. Thus, its use cannot be dismissed on simple fashion arguments and, as usual, in science, the tree is to be judged by the fruit.

Recognition of Lewis X by Anti-Lex Monoclonal Antibody IG5F6

mAbs directed toward the Lewis X (Le^x) determinant have been shown to display different specificities, depending on the presentation of Le^x to the immune system. Of interest is the murine anti-Le^x mAb IG5F6, generated against the O chain polysaccharide of Helicobacter pylori that contains polymeric Le^x structures. The mAb was found to have a higher affinity for polymeric Le^x over monomeric Le^x In this study, we explore the recognition of monomeric Le^x by IG5F6 using a panel of Le^x analogues in which N-acetyl-d-glucosamine, l-fucose, or d-galactose (D-Gal) are replaced with d-glucose and/or l-rhamnose. Our studies show that all analogues were weaker inhibitors than the Le^x Ag, indicating that all three residues are essential in the recognition of Le^x by mAb IG5F6. We explored the involvement of 4″-OH of d-Gal in the binding with IG5F6 using a panel of 4″-modified Le^x analogues. Although the 4″-OH is only involved in a weak polar interaction, we conclude that the D-Gal residue in Le^x is primarily involved in aromatic stacking interactions with the Ab binding site. We compared these results to our work with mAb SH1. Although stacking interactions between D-Gal and an aromatic residue was also suggested for SH1, an H-bond involving the 4″-OH was identified that is not found in the binding of IG5F6 to Le^x Thus, anti-Le^x mAbs SH1 and IG5F6 bind to Le^x in different manners, even though the hydrophobic patch displayed by the β-galactoside in Le^x is essential in both cases for their binding to Le^x.

Conformational characterization of a novel anti-HER2 candidate antibody

Regulatory agencies establish that a broad physicochemical and biological characterization is necessary for the evaluation of comparability between a biosimilar candidate product and a reference commercial drug. Between them, conformational characterization of proteins is of vital importance to determine its folding and biological functions. In this work, the conformational features of a novel monoclonal antibody (called 5G4) were evaluated by means of circular dichroism spectroscopy and fluorescence. Secondary structure and thermal stability of mAbs were determined by circular dichroism in the far ultraviolet, while three-dimensional folding of proteins was analyzed by both circular dichroism in the near ultraviolet and intrinsic tryptophan fluorescence. In all experiments, Herceptin (Roche) was used as control. Both antibodies showed a composition of secondary structure predominantly of β-sheets (55–56%) and thermal stability of ~ 75°C, suggesting structural similarity. The three-dimensional folding of proteins was also similar due to the absorption spectra of the aromatic residues and the emission wavelength maxima by fluorescence were comparable. The values of the fluorescence attenuation constant (Stern-Volmer constant) for increasing concentrations of acrylamide were also similar, suggesting a degree of exposure of tryptophan residues similar, although it was slightly decreased for Herceptin. Our data permit to consider that 5G4 monoclonal antibody showed similar conformational characteristics when compared with Herceptin.

Deamidation of Amino Acids on the Surface of Adeno-Associated Virus Capsids Leads to Charge Heterogeneity and Altered Vector Function

Post-translational modification of the adeno-associated virus capsids is a poorly understood factor in the development of these viral vectors into pharmaceutical products. Here we report the extensive capsid deamidation of adeno-associated virus serotype 8 and seven other diverse adeno-associated virus serotypes, with supporting evidence from structural, biochemical, and mass spectrometry approaches. The extent of deamidation at each site depended on the vector's age and multiple primary-sequence and three-dimensional structural factors. However, the extent of deamidation was largely independent of the vector recovery and purification conditions. We demonstrate the potential for deamidation to impact transduction activity and, moreover, correlate an early time point loss in vector activity to rapidly progressing spontaneous deamidation at several adeno-associated virus 8 asparagines. We explore mutational strategies that stabilize side-chain amides, improving vector transduction and reducing the lot-to-lot molecular variability that presents a key concern in biologics manufacturing. This study illuminates a previously unknown aspect of adeno-associated virus capsid heterogeneity and highlights its importance in the development of these vectors for gene therapy.

Kinetics and Characterization of Non-enzymatic Fragmentation of Monoclonal Antibody Therapeutics

PURPOSE

To understand non-enzymatic hydrolytic fragmentation of a monoclonal antibody therapeutic under temperature stressed conditions and investigating possible mechanism for the same.

METHODS

The mAb therapeutic was incubated at 50°C in phosphate buffer at pH 6.5 and fragmentation was monitored at different ionic strengths under stressed conditions. The incubated mAb was sampled at regular time intervals by analytical Size Exclusion Chromatography (SEC).

RESULTS

It was observed that 57% of the mAb product fragmented over 4 days into two fragment species - Fc-Fab and Fab with molecular weights of 97 KDa and 47 KDa, respectively, as measured by mass spectrometry (MS) and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The fragmentation rate was slow initially and then accelerated with time. No change in % aggregate level was observed in this duration, implying that degradation was primarily via fragmentation at high temperature. Kinetics of hydrolytic fragmentation was hypothesized and SEC data was fitted to estimate the kinetic rate constants. While degradation of the monomer into fragment species was non-Arrhenius with a negative activation energy, further degradation of Fab-Fc fragments into Fab or Fc fragments followed Arrhenius Law with an activation energy of 2.1 and 15.38 kcal/mol, respectively.

CONCLUSION

High temperature (50°C) causes mAb to cleave at the hinge region to form Fab-Fc and Fab/Fc, as confirmed by dynamic light scattering, SDS-PAGE, SEC, and MS. A kinetic model for hydrolytic fragmentation has been proposed. The results are expected to assist end users in formulation development as well as in monitoring stability of biotherapeutic products.

A long non-coding SINEUP RNA boosts semi-stable production of fully human monoclonal antibodies in HEK293E cells

Use of monoclonal antibodies is emerging as a highly promising and fast-developing scenario for innovative treatment of viral, autoimmune and tumour diseases. The search for diagnostic and therapeutic antibodies currently depends on in vitro screening approaches, such as phage and yeast display technologies. Antibody production still represents a critical step for preclinical and clinical evaluations. Accordingly, improving production of monoclonal antibodies represents an opportunity, to facilitate downstream target validations. SINEUP RNAs are long non-coding transcripts, possessing the ability to enhance translation of selected mRNAs. We applied SINEUP technology to semi-stable production of monoclonal antibodies in HEK293E cells, which allows for episomal propagation of the expression vectors encoding the heavy and light chains of IgGs. Co-expression of SINEUP RNA with mRNAs encoding heavy and light chains of IgG4s was able to increase the production of different anti-CLDN1 antibodies up to three-fold. Improved production of monoclonal antibodies was achieved both in transiently transfected HEK293E cells and in cellular clones with stable expression of the SINEUP. Compared to antibody preparations obtained under standard conditions, the anti-CLDN1 IgG4s produced in the presence of the SINEUP transcript showed unaltered post-translational modifications, and retained the ability to recognize their target. We thus propose SINEUP technology as a valuable tool to enhance semi-stable antibody production in human cell lines.

Role of the constant region domain in the structural diversity of human antibody light chains

Issues regarding the structural diversity (heterogeneity) of an antibody molecule have been the subject of discussion along with the development of antibody drugs. Research on heterogeneity has been extensive in recent years, but no clear solution has been reached. Heterogeneity is also observed in catalytic antibody κ light chains (CLs). In this study, we investigated how the constant region domain of CLs concerns structural diversity because it is a simple and good example for elucidating heterogeneity. By means of cation-exchange chromatography, SDS-PAGE, and 2-dimensional electrophoresis for the CL, multimolecular forms consisting of different electrical charges and molecular sizes coexisted in the solution, resulting in the similar heterogeneity of the full length of CLs. The addition of copper ion could cause the multimolecular forms to change to monomolecular forms. Copper ion contributed greatly to the enrichment of the dimer form of CL and the homogenization of the differently charged CLs. Two molecules of the CL protein bound one copper ion. The binding affinity of the ion was 48.0 μM^-1 Several divalent metal ions were examined, but only zinc showed a similar effect.-Hifumi, E., Taguchi, H., Kato, R., Uda, T. Role of the constant region domain in the structural diversity of human antibody light chains.

Prediction of intraocular antibody drug stability using ex-vivo ocular model

Following intravitreal (IVT) injection, therapeutic proteins get exposed to physiological pH, temperature and components in the vitreous humor (VH) for a significantly long time. Therefore, it is of interest to study the stability of the proteins in the VH. However, the challenge posed by the isolated VH (such as pH shift upon isolation and incubation due to the formation of smaller molecular weight (M_W) degradation products) can result in artefacts when investigating protein stability in relevance for the actual in vivo situation. In this current study, an ex-vivo intravitreal horizontal stability model (ExVit-HS) has been successfully developed and an assessment of long-term stability of a bi-specific monoclonal antibody (mAb) drug in the isolated VH for 3months at physiological conditions has been conducted. The stability assessment was performed using various analytical techniques such as microscopy, UV visible for protein content, target binding ELISA, Differential Scanning Calorimetry (DSC), Capillary-electrophoresis-SDS, Size Exclusion (SEC) and Ion-exchange chromatography (IEC) and SPR-Biacore. The results show that the ExVit-HS model was successful in maintaining the VH at physiological conditions and retained a majority of protein in the VH-compartment throughout the study period. The mAb exhibited significantly less fragmentation in the VH relative to the PBS control; however, chemical stability of the mAb was equally compromised in VH and PBS. Interestingly, in the PBS control, mAb showed a rapid linear loss in the binding affinity. The loss in binding was almost 20% higher compared to that in VH after 3months. The results clearly suggest that the mAb has different degradation kinetics in the VH compared to PBS. These results suggest that it is beneficial to investigate the stability in the VH for drugs intended for IVT injection and that are expected longer residence times in the VH. The studies show that the ExVit-HS model may become a valuable tool for evaluating stability of protein drugs and other molecules following IVT injection.

A novel method of preparing the monoform structure of catalytic antibody light chain

Along with the development of antibody drugs and catalytic antibodies, the structural diversity (heterogeneity) of antibodies has been given attention. For >20 yr, detailed studies on the subject have not been conducted, because the phenomenon presents many difficult and complex problems. Structural diversity provides some (or many) isoforms of an antibody distinguished by different charges, different molecular sizes, and modifications of amino acid residues. For practical use, the antibody and the subunits must have a defined structure. In recent work, we have found that the copper (Cu) ion plays a substantial role in solving the diversity problem. In the current study, we used several catalytic antibody light chains to examine the effect of the Cu ion. In all cases, the different electrical charges of the molecule converged to a single charge, giving 1 peak in cation-exchange chromatography, as well as a single spot in 2-dimensional gel electrophoresis. The Cu-binding site was investigated by using mutagenesis, ultraviolet-visible spectroscopy, atomic force microscope analysis, and molecular modeling, which suggested that histidine and cysteine residues close to the C-terminus are involved with the binding site. The constant region domain of the antibody light chain played an important role in the heterogeneity of the light chain. Our findings may be a significant tool for preparing a single defined, not multiple, isoform structure.