Microbial expression of Exendin-4 analog and its efficacy in mice model.

Exendin-4 is a GLP 1 agonist incretin-mimetic peptide hormone comprising 39 amino acids. Exenatide (Byetta®) is a chemically synthesized version of Exendin-4 with an additional C-terminal amidation. Exenatide acts as a GLP-1 receptor agonist. This paper illustrates the method adopted for cloning, fermentation and purification of recombinant Exendin-4 analog expressed in Escherichia coli. The biologically expressed analog was extensively characterized using different orthogonal methods to confirm their biological activity and physicochemical properties. It was observed that the expressed analog showed comparable functional properties as that of Byetta® irrespective of their modes of development. Further, in vivo efficacy of the recombinant Exendin-4 analog was studied in Oral Glucose Tolerance Test (OGTT) in mice models. Byetta® and Exendin-4 analog treated groups showed comparable glucose lowering activity in the OGTT model.

Charge variant analysis of proposed biosimilar to Trastuzumab.

Trastuzumab is a humanized monoclonal antibody (mAb) employed for the treatment of HER2 Positive Breast Cancer. A HER2 overexpressing tumor cell binds to Trastuzumab and attracts immune cells which lead to induction of Antibody Dependent Cellular Cytotoxicity (ADCC) by binding to Fc receptors (CD16a or FcγRIIIa) on an effector cell, such as natural killer (NK) cells. The most commonly expressed receptor on NK cell is CD16a which binds to the Fc portion of Trastuzumab. The ligand-independent HER2-HER3 dimerization is the most potent stimulator of downstream pathways for regulation of cell growth and survival. An attempt has been made in this study to understand the impact of charge heterogeneity on the binding kinetics and potency of the monoclonal antibody. Trastuzumab has a pI range of 8.7-8.9 and is composed of mixture of acidic and basic variants beside the main peak. Ion exchange chromatography was used to isolate the acidic, basic, and main peak fractions from in-house proposed biosimilar to Trastuzumab and their activities were compared to the Innovator Trastuzumab Herclon®. Data from the mass analysis confirmed the potential modifications in both acidic and basic variant. Binding activity studies performed using Surface Plasmon Resonance (SPR) revealed that acidic variants had lesser binding to HER2 in comparison to the basic variants. Both acidic and basic variant showed no significant changes in their binding to soluble CD16a receptors. In vitro assay studies using a breast cancer cell line (BT-474) confirmed the binding potency of acidic variant to be lesser than basic variant, along with reduced anti-proliferative activity for the acidic variant of Trastuzumab. Overall, these data has provided meaningful insights to the impact of antibody charge variants on in vitro potency and CD16 binding affinity of trastuzumab.

Intracellular delivery of antibodies by chimeric Sesbania mosaic virus (SeMV) virus like particles.

The therapeutic potential of antibodies has not been fully exploited as they fail to cross cell membrane. In this article, we have tested the possibility of using plant virus based nanoparticles for intracellular delivery of antibodies. For this purpose, Sesbania mosaic virus coat protein (CP) was genetically engineered with the B domain of Staphylococcus aureus protein A (SpA) at the ßH-ßI loop, to generate SeMV loop B (SLB), which self-assembled to virus like particles (VLPs) with 43 times higher affinity towards antibodies. CP and SLB could internalize into various types of mammalian cells and SLB could efficiently deliver three different monoclonal antibodies-D6F10 (targeting abrin), anti-α-tubulin (targeting intracellular tubulin) and Herclon (against HER2 receptor) inside the cells. Such a mode of delivery was much more effective than antibodies alone treatment. These results highlight the potential of SLB as a universal nanocarrier for intracellular delivery of antibodies.