Using a Dihydrofolate Reductase-Based Strategy for Producing the Biosimilar Version of Pertuzumab in CHO-S Cells

Anti-CD8/IL-15 (N72D)/sushi fusion protein: A promising strategy for improvement of cancer immunotherapy

BACKGROUND

To overcome the limitations of IL-15 and to improve the efficacy of IL-15 in immunotherapy, several strategies have been introduced.

OBJECTIVE

The objective of this study was to generate and evaluate a novel anti-CD8/IL-15 (N72D)/Sushi fusion protein with the potential to target CD8+ T cells and enhance functionality of CD8+ T cells against tumor cells.

METHODS

In this connection, a novel fusokine that contains IL-15(N72D), a Sushi domain, and anti-CD8 single-chain fragment variable (scFv) was designed. The size accuracy and binding potency of the isolated protein were assessed using western blotting and indirect surface staining. Following purification, the potential function of the anti-CD8/IL-15(N72D)/Sushi fusion protein in the induction of proliferation and cytotoxicity of CD8+ T cells was evaluated.

RESULTS

In-silico analysis revealed that fusokine is structurally stable, correctly folded and can interact with the CD8 co-receptor. Both fusokine and IL-15(N72D)/Sushi were produced in CHO-S cell line with a final concentration of 18.43 mg/l and 12.64 mg/l respectively. Fusokine bound to 97.6 % of CD8+ T cells and significantly induced T cell proliferation and cytotoxic potential in peripheral blood mononuclear cells (PBMCs) in a time dependent manner. Compared to both the control and the IL-15 (N72D)/sushi treated groups, fusokine showed superior potential in CD8+ T cell functionality.

CONCLUSION

Anti-CD8/IL-15(N72D)/Sushi has the ability to effectively target CD8+ T cells, promote lymphocyte proliferation and induce cytotoxicity against tumor cells. Due to its promising properties, it could be considered as a new potential immunotherapy approach.

Enhancing cancer immunotherapy with Anti-NKG2D/IL-15(N72D)/Sushi fusion protein: Targeting cytotoxic immune cells and boosting IL-15 efficacy

BACKGROUND

There are a number of distinct challenges and complexities associated with administering IL-15 for cancer immunotherapy that must be taken into consideration.

OBJECTIVE

The purpose of this study was to design a fusion protein for targeting cytotoxic immune cells and enhance IL-15 efficiency.

METHODS

A fusokine that contains IL-15(N72D), a Sushi domain, and anti-NKG2D scFv was designed. The fusion protein was in-silico modeled using the Swiss model server, followed by docking and molecular dynamics simulations. The in-vitro purified fusokine was evaluated using dot blot and Western blot. Then, flow cytometry was employed to evaluate biological properties such as proliferation, cytotoxicity, and degranulation.

RESULTS

Fusokine and IL-15(N72D)/Sushi, which had molecular weights of about 52 kDa and 26 kDa, respectively, were expressed in CHO-K1 cells. The fusokine binds 69.6 % of the CHO-NKG2D+ cells that express 83.1 % NKG2D. Both the fusokine and the IL-15(N72D)/Sushi significantly stimulate the proliferation of lymphocytes. After 14 days of growth, the vitality of untreated cells decreased to about 17.5 %, but 82.2 % and 56.6 % of cells were still alive when fusokine and IL-15(N72D)/Sushi were present. Furthermore, administration of fusokine was associated with the highest rates of target tumor cell cytotoxicity. Additionally, although it was not statistically significant, fusokine increased the expression of CD107a and granzyme B by 1.25 times and 2.4 times, respectively.

CONCLUSION

The fusokine possesses the capability to stimulate the survival and multiplication of lymphocytes, as well as their ability to eliminate tumors. These characteristics have led to its consideration as a potential treatment for immunotherapy.

Anti-CD19/CD8 bispecific T cell engager for the potential treatment of B cell malignancies

The administration of blinatumomab was accompanied by several adverse effects, including activation of regulatory T-cells and cytokine storm. The objective of this study was to produce and evaluate a novel αCD8/CD19 BiTE (αCD8/CD19) with the potency to directly target CD8+T-cells. In-silico studies were utilized for determining proper folding, receptor binding, and structural stability of αCD8/CD19 protein. Western blotting and indirect surface staining were used to evaluate the size accuracy and binding potency of the purified protein. Functionality was assessed for granzyme B production, cytotoxicity, and proliferation. TheαCD8/CD19recombinant protein was produced in the CHO-K1 cell line with a final concentration of 1.94 mg/l. The αCD8/CD19 bound to CD8+and CD19+cell lines and induced significant granzyme B production, cytotoxic activity and proliferation potential in the presence of IL-2 and tumor target cells. The maximum CD8+T-cell biological activity was observed on the 10th day with 10:1 effector-to-target ratio.

Production of a biosimilar version of aflibercept to improve VEGF blocker cytotoxicity on endothelial cells

This project aimed to produce a biosimilar version of aflibercept (AFL) and evaluate the effect of the co-treatment of AFL with other vascular endothelial growth factor (VEGF) blocker drugs. For this purpose, the optimized gene was inserted into the pCHO1.0 plasmid and transfected into the CHO-S cell line. The final concentration of biosimilar-AFL for the selected clone was 782 mg/L. Results revealed that the inhibition potential of the biosimilar-AFL on HUVEC cells was significant at 10 and 100 nM concentrations and in a dose-dependent manner. Furthermore, co-treatment of biosimilar-AFL with Everolimus (EVR), Lenvatinib (LEN), and Sorafenib (SOR) could reduce HUVEC cell viability/proliferation, more than when used alone. When LEN and SOR were co-treated with biosimilar-AFL, their cytotoxicity increased 10-fold. The most and least efficient combination was seen when biosimilar-AFL combined with LEN and EVR, respectively. Finally, biosimilar-AFL may improve the efficiency of LEN, EVR, and SOR in reducing the VEGF effect on endothelial cells.

Triggering of lymphocytes by CD28, 4-1BB, and PD-1 checkpoints to enhance the immune response capacities

Tumor infiltrating lymphocytes (TILs) usually become exhausted and dysfunctional owing to chronic contact with tumor cells and overexpression of multiple inhibitor receptors. Activation of TILs by targeting the inhibitory and stimulatory checkpoints has emerged as one of the most promising immunotherapy prospectively. We investigated whether triggering of CD28, 4-1BB, and PD-1 checkpoints simultaneously or alone could enhance the immune response capacity of lymphocytes. In this regard, anti-PD-1, CD80-Fc, and 4-1BBL-Fc proteins were designed and produced in CHO-K1 cells as an expression host. Following confirmation of the Fc fusion proteins' ability to bind to native targets expressed on engineered CHO-K1 cells (CHO-K1/hPD-1, CHO-K1/hCD28, CHO-K1/hCTLA4, and CHO-K1/h4-1BB), the effects of each protein, on its own and in various combinations, were assessed in vitro on T cell proliferation, cytotoxicity, and cytokines secretion using the Mixed lymphocyte reaction (MLR) assay, 7-AAD/CFSE cell-mediated cytotoxicity assay, and a LEGENDplex™ Human Th Cytokine Panel, respectively. MLR results demonstrated that T cell proliferation in the presence of the combinations of anti-PD-1/CD80-Fc, CD80-Fc/4-1BBL-Fc, and anti-PD-1/CD80-Fc/4-1BBL-Fc proteins was significantly higher than in the untreated condition (1.83-, 1.91-, and 2.02-fold respectively). Furthermore, anti-PD-1 (17%), 4-1BBL-Fc (19.2%), anti-PD-1/CD80-Fc (18.6%), anti-PD-1/4-1BBL-Fc (21%), CD80-Fc/4-1BBL-Fc (18.5%), and anti-PD-1/CD80-Fc/4-1BBL-Fc (17.3%) significantly enhanced cytotoxicity activity compared to untreated condition (7.8%). However, concerning the cytokine production, CD80-Fc and 4-1BBL-Fc alone or in combination significantly increased the secretion of IFN-γ, TNF-α, and IL-2 compared with the untreated conditions. In conclusion, this research establishes that the various combinations of produced anti-PD-1, CD80-Fc, and 4-1BBL-Fc proteins can noticeably induce the immune response in vitro. Each of these combinations may be effective in killing or destroying cancer cells depending on the type and stage of cancer.

Tatibody, a recombinant antibody with higher internalization potency

Using antibody drug conjugates (ADC) which can exclusively bind to their target cells and upon internalization release their toxic agent, is one of the most effective methods for killing tumor cells. Therefore, increasing the internalization rate is an important factor for tumor treatment in this case. The aim of the present study was to develop a new variant of pertuzumab (an anti-ErbB2 humanized antibody) with higher internalization rate that can be a good candidate for the production of ADC. To this end, the Human Immunodeficiency Virus TAT Protein Transduction Domain (TAT-PTD) was replaced into the structure of the pertuzumab. At first, the best site in antibody heavy chain constant region for the replacement of TAT-PTD was predicted through computational methods. Then, the resulting recombinant antibody, of which TAT-PTD was located at amino acid position 130-140 and named Tatibody, was produced in CHO-S cell line. Finally, its physicochemical properties and biological activities were evaluated and compared with pertuzumab. Results showed that the binding ability of Tatibody to the ErbB2 receptor is similar to that of pertuzumab, but its internalization potency is 3.6 fold higher and can be used as a good candidate for ADC construction.

In vitro cytotoxic effect of Trastuzumab in combination with Pertuzumab in breast cancer cells is improved by interleukin-2 activated NK cells

Targeting erb-b2 receptor tyrosine kinase 2 (ERBB2) using the combination of Trastuzumab and Pertuzumab has demonstrated promising results in breast cancer therapy. It has further been revealed that interleukin-2 (IL-2) can activate Natural Killer cells (NK cells) and elevate their cytotoxic potency against tumor cells. In this study, we explored the cytotoxic effect of recombinant human IL-2 in combination with Trastuzumab and Pertuzumab on the ERBB2 positive (SK-BR-3) and negative (MDA-MB-231) breast cancer cell lines. The cytotoxicity level of IL-2 activated NK cells (approximately 75%) were significantly higher than untreated cells (approximately 55%) in the presence of Trastuzumab and Pertuzumab against SK-BR-3 cells, while no difference was observed in the case of MDA-MB-231 cells (about 15%).