Protein production for R&D
Experimental, therapeutic, and commercial applications require the production of high-quality recombinant proteins at a certain scale. However, generating the desired quality and amount of recombinant proteins can be a challenging task especially when the protein is a “difficult-to-express” protein. With TapBoost, the expression level of target recombinant proteins can be significantly increased. TapBoost has successfully enhanced the production of many recombinant proteins. Intriguingly, the expression of difficult-to-express proteins such as G protein-coupled receptor (GPCR) was also improved by the technology and GPCR protein expressed by the technology was strongly activated by the ligand binding.
Example 1 – IL13Rα2
Two difficult-to-express proteins, IL13Rα2 and FVII, were expressed in our mammalian transient expression system. IL13Rα2 is a receptor for IL13 and its truncated form (TF) is a secreted protein. The Fc-fusion protein of IL13Rα2 (IL13Rα2-Fc) has a potential to treat many autoimmune diseases such as asthma and COPD. FVII is the serine esterase of the extrinsic coagulation pathway and is widely used to treat a variety of bleeding complications. Its Fc fusion protein has been developed to treat hemophilia.
Example 2 – Factor VIII for Hemophilia
Factor VIII is the responsible protein for hemophilia A, a disorder that causes serious bleeds and can lead to degenerative joint disease. The primary treatment for hemophilia A is replacement therapy using infusions of clotting factors, mainly Factor VIII.
Factor VIII is extremely difficult to manufacture due to protein folding problems. Therefore, yields are low and often inconsistent. Clotting factor concentrate accounted for 70-82% of the annual $155,000 cost of hemophilia treatment (2008) as the broader hemophilia market will grow at an average 5.9% rate over the next five years, from $8.5 billion in 2011 to $11.4 billion in 2016, one can see the huge potential cost savings in reducing the costs of the clotting factor concentrate.
TapBoost dramatically enhances the production of Factor VIII-Fc. FVIII is extremely difficult to produce using current recombinant DNA technology. Most of the exogenously expressed FVIII becomes trapped in ER. An Fc fusion protein of FVIII with Fc domain (FVIII-Fc) was developed to extend the half-life of FVIII, and approved by the FDA in 2013 (ELOCTATE™; Biogen Idec). We found that the FVIII-Fc is secreted poorly. FVIII-Fc expressed in cultured cells could be hardly detected by sandwich ELISA (upper panel) or activity assay (bottom panel). However, when FVIII-Fc was expressed with TapBoost, it was readily detected (third bar) representing an increase of more than 20 fold.