Reading Bio-process Papers: The Evolution of CHO Cell Development, Part 9
Hello everyone. Currently, the development of ADCs and multispecific antibodies is flourishing, and the momentum of antibody therapeutics is accelerating more and more. To manufacture these antibody therapeutics, it is necessary to develop CHO cell lines that efficiently produce antibodies. In doing so, the target antibody gene is integrated into the CHO cell genome, and there is an evolution occurring in the methods of gene introduction. This technological evolution is explained in detail in the paper titled "The new frontier in CHO cell line development: From random to targeted transgene integration technologies." The URL for the paper is provided below.
https://doi.org/10.1016/j.biotechadv.2024.108402
In this Note post, the goal is to read through this paper steadily, bit by bit, and ultimately understand this technological evolution. We have already finished the section on the existing technology, Random Transgene Integration, and starting from the last post, we entered the section on Semi-targeted transgene Integration. Today, for the ninth installment, we will study 3.2. Transposase/transposon systems and their implementation in CHO cell line development.
Also, please refer to the magazine below, where past posts (parts 1 through 8) are archived.
Now, let's translate 3.2. Transposase/transposon systems and their implementation in CHO cell line development.
3.2. Transposase/transposon systems and their implementation in CHO cell line development
Transposase/transposon systems are gaining importance in recent industrial CHO cell line development (CLD) processes due to their high integration efficiency and ease of implementation, regardless of the host cell type or culture medium system used. Although these tools were discovered decades ago, it is relatively recently that they have begun to attract serious attention in the field of biopharmaceutical research (Cary et al., 1989). Currently, commercially available transposase systems commonly used in biopharmaceutical R&D include Sleeping Beauty, PiggyBac, Leap-In®, and DirectedLuck™ (Table 2). Of particular note is that all of these (and some commercialized) transposase systems have undergone systematic optimization, such as enhancing functionality through protein engineering, and exhibit higher functionality compared to their wild-type originals (Burnight et al., 2012; Cui et al., 2002; Mátés et al., 2009) (Table 3).
Note 1) Table 2 is a list of engineering methods for constructing transposase systems used in CHO cells.
Note 2) Table 3 is a comparison of transposase-based systems used for stable cell line construction in CHO cells, including titer data. Please be sure to check the tables in the paper via the link.
Continuing with the translation.
The fact that the number of available transposase systems is relatively small indicates how difficult it is to discover functional novel transposases. Most transposases have been inactivated or genetically silenced by host organisms during the course of evolution. This is because constantly active (constitutively active) transposons cause genomic instability and have detrimental effects on the organism (Hsu et al., 2021). Furthermore, because transposases often have very high specificity for the DNA sequences they recognize, it is extremely difficult to identify new target sequences in the genome that possess the corresponding transposon ITR sequences. This difficulty is further compounded, especially if the sequences flanking the transposase gene have mutated during evolution.
Thus, the number of commercially available transposase systems is limited, and their use is often constrained by high licensing fees and unfavorable commercial terms. Nevertheless, there is potential for innovation and improvement in CLD workflows using transposases, and in the long term, the high initial investment may be at least partially justified.
That concludes the Japanese translation.
Finally, to summarize the key points directly related to CLD:
1. Transposase/transposon systems are promising as high-efficiency and flexible integration methods in CLD.
- High integration efficiency and easy implementation, independent of host cell type or culture medium system.
- Commercial systems such as Sleeping Beauty, PiggyBac, and Leap-In® are being used.
2. While there are cost and contractual constraints for commercial adoption, it may lead to the innovation and improvement of CLD workflows in the long term.
- The number of commercially available systems is limited, and licensing fees and commercial terms are barriers to adoption.
- Even so, the technical benefits obtained may justify the initial investment in the long run.
Next time, we will proceed to 3.2.1. The sleeping beauty transposase system. Thank you for your time.