Biobetters From an Integrated Computational/Experimental Approach

Peptides for microbe-induced cancers: latest therapeutic strategies and their advanced technologies

Cancer is a significant global health concern associated with multiple distinct factors, including microbial and viral infections. Numerous studies have elucidated the role of microorganisms, such as Helicobacter pylori (H. pylori), as well as viruses for example human papillomavirus (HPV), hepatitis B virus (HBV), and hepatitis C virus (HCV), in the development of human malignancies. Substantial attention has been focused on the treatment of these microorganism- and virus-associated cancers, with promising outcomes observed in studies employing peptide-based therapies. The current paper provides an overview of microbe- and virus-induced cancers and their underlying molecular mechanisms. We discuss an assortment of peptide-based therapies which are currently being developed, including tumor-targeting peptides and microbial/viral peptide-based vaccines. We describe the major technological advancements that have been made in the design, screening, and delivery of peptides as anticancer agents. The primary focus of the current review is to provide insight into the latest research and development in this field and to provide a realistic glimpse into the future of peptide-based therapies for microbe- and virus-induced neoplasms.

A comprehensive strategy for the identification of biologics by liquid-chromatography-mass spectrometry for release testing in a regulated environment

Identification (ID) testing is a regulatory requirement for biopharmaceutical manufacturing, requiring robust, GMP-qualified assays that can distinguish the therapeutic from any other in the facility. Liquid Chromatography-Mass Spectrometry (LC-MS) is a powerful analytical tool used to identify and characterize biologics. While routinely leveraged for characterization, LC-MS is relatively rare in Quality Control (QC) settings due to its perceived complexity and scarcity of MS-trained personnel. However, employing LC-MS for identification of drug products has many advantages versus conventional ID techniques, including but not limited to its high specificity, rapid turn-around time, and ease of method execution. In this work, we outline the development and implementation of a comprehensive LC-MS based ID strategy for biologics release testing. Two main workflows (WFs) were developed: i) WF1, a subunit-based assay measuring the molecular weight of the light chain (LC) and heavy chain (HC) of an antibody upon reduction, and ii) WF2, intact mass measurement of the biologic upon N-deglycosylation by PNGase F. The proposed strategy is shown to be applicable for over 40 diverse model biologics including monoclonal antibodies (mAbs), biobetters such as antibody prodrugs/afucosylated mAbs, fusion proteins, multi-specific antibodies, Fabs, and large peptides, all with excellent mass accuracy (error typically < 20 ppm) and precision. It requires a single-step sample preparation and a single click to run and process the data upon method setup. This strategy has been successfully implemented for release testing in GMP labs. Challenges and considerations for the establishment of QC-friendly methods are discussed. It is also shown that these methods can be applied to the ID of more analytically complex biotherapeutics, such as fixed-dose combination (FDC) and drug products co-formulated with trace-level additives.

Glycan Profile Analysis of Engineered Trastuzumab with Rationally Added Glycosylation Sequons Presents Significantly Increased Glycan Complexity

Protein aggregation constitutes a recurring complication in the manufacture and clinical use of therapeutic monoclonal antibodies (mAb) and mAb derivatives. Antibody aggregates can reduce production yield, cause immunogenic reactions, decrease the shelf-life of the pharmaceutical product and impair the capacity of the antibody monomer to bind to its cognate antigen. A common strategy to tackle protein aggregation involves the identification of surface-exposed aggregation-prone regions (APR) for replacement through protein engineering. It was shown that the insertion of N-glycosylation sequons on amino acids proximal to an aggregation-prone region can increase the physical stability of the protein by shielding the APR, thus preventing self-association of antibody monomers. We recently implemented this approach in the Fab region of full-size adalimumab and demonstrated that the thermodynamic stability of the Fab domain increases upon N-glycosite addition. Previous experimental data reported for this technique have lacked appropriate confirmation of glycan occupancy and structural characterization of the ensuing glycan profile. Herein, we mutated previously identified candidate positions on the Fab domain of Trastuzumab and employed tandem mass spectrometry to confirm attachment and obtain a detailed N-glycosylation profile of the mutants. The Trastuzumab glycomutants displayed a glycan profile with significantly higher structural heterogeneity compared to the HEK Trastuzumab antibody, which contains a single N-glycosylation site per heavy chain located in the CH2 domain of the Fc region. These findings suggest that Fab N-glycosites have higher accessibility to enzymes responsible for glycan maturation. Further, we have studied effects on additional glycosylation on protein stability via accelerated studies by following protein folding and aggregation propensities and observed that additional glycosylation indeed enhances physical stability and prevent protein aggregation. Our findings shed light into mAb glycobiology and potential implications in the application of this technique for the development of “biobetter” antibodies.

Enhancing the stability of adalimumab by engineering additional glycosylation motifs

Monoclonal antibodies (mAbs) are of high value in the diagnostic and treatment of many debilitating diseases such as cancers, auto-immune disorders and infections. Unfortunately, protein aggregation is one of the ongoing challenges, limiting the development and application of mAbs as therapeutic products by decreasing half-life, increasing immunogenicity and reducing activity. We engineered an aggregation-prone region of adalimumab, the top selling mAb product worldwide - with additional glycosylation sites to enhance its resistance to aggregation by steric hindrance as a next generation biologic. We found that the addition of N-glycans in the Fab domain significantly enhanced its conformational stability, with some variants increasing the melting temperature of the Fab domain by >6 °C. The mutations tested had minimal impact on antigen binding affinity, or affinity to Fcγ receptors responsible for effector function. Our findings highlight the significant utility of this rational engineering approach for enhancing the conformational stability of therapeutic mAbs and other next-generation antibody formats.

Choline ionic liquid enhances the stability of Herceptin® (trastuzumab)

We investigated the effect of an emerging biocompatible ionic liquid, choline dihydrogen phosphate (CDHP), on the stability of high-concentration formulations of Herceptin® (trastuzumab). Our results show that CDHP significantly suppresses unfolding and aggregation of trastuzumab, demonstrating great promise as an additive in the development of stable therapeutic antibody formulations.

In silico and in vivo analyses of the mutated human tissue plasminogen activator (mtPA) and the antithetical effects of P19 silencing suppressor on its expression in two Nicotiana species

Human tissue-type plasminogen activator is one of the most important therapeutic proteins involved in the breakdown of blood clots following the stroke. A mutation was found at position 1541 bp (G514E) and the mutated form was cloned into the binary vector pTRAc-ERH. In silico analysis showed that this mutation might have no significant effect on the active site of the tissue plasminogen activator enzyme. Accordingly, zymography assay confirmed the serine protease activity of the mutated form and its derivatives. The expression of the mutated form was verified with/without co-agroinjection of the P19 gene silencing suppressor in both Nicotiana tabacum and N. benthamiana. The ELISA results showed that the concentration of the mutated form in the absence of P19 was 0.65% and 0.74% of total soluble protein versus 0.141% and 1.36% in the presence of P19 in N. benthamiana and N. tabacum, respectively. In N. tabacum, co-agroinjection of P19 had the synergistic effect and increased the mutated tissue plasminogen activator production two-fold higher. However, in N. benthamiana, the presence of P19 had the adverse effect of five-fold reduction in the concentration. Moreover, results showed that the activity of the mutated form and its derivatives was more than that of the purified commercial tissue plasminogen activator.