Human Embryonic
Kidney Cells
Abstract
The production of complex biochemical molecules like viral vectors and recombinant proteins depends on mammalian cell-based expressions (Ho & Too, 2020; Sennesael et al., 2018). Despite the majority of the available biotherapeutics being produced in cell lines of animals, the production in human cell lines is currently expanding (Zhao et al., 2020; Abaandou et al., 2021). The use of human cell lines has been associated with an increased potential, which promotes more "human-like" post-translational modifications to be carried out by the resulting biotherapeutics (Deng et al., 2020; Leinonen et al., 2020; İlhan, 2021). Among all human cell lines, the human embryonic kidney (HEK293) is extensively used because of its rapid growth rate, high reflectivity, and ability to grow in serum-free suspension culture (Dohogne et al., 2019; Bezeljak, 2022; Chen et al., 2018). In this paper, we discuss what the viral vector production in HEK293 is, in addition to its derivative history. We also elaborate on the uses of HEK293 and the ethics surrounding these uses, among other aspects.
Introduction
The development of most biopharmaceutical products mainly relies on human cell lines, where the therapeutic products are made in the Chinese hamster ovary (CHO) cells (Labant, 2021). Using human cell lines allows it to produce complex post-translational modifications (PTMs) (Maldonado et al., 2020; (Vaitkienė et al., 2020). Biologics such as clotting, growth, and antibodies are considered complex and require complex PTMs to maintain the product's effectiveness and stability (Do Minh & Kamen, 2021; Aponte-Ubillus et al., 2018; Egan et al., 2018). Most therapeutic viral vectors and some recombinant proteins require PTMs that cannot be met in CHO, hence produced in HEK293 (Selvaraj et al., 2021; Pulix et al., 2021; Dehbashi et al., 2019; Wu et al., 2019). From 2015, the Food and Drug Association (FDA) approved only seven HEK-derived products, of which six are mainly cell and gene therapies, while the HEK293 cell line and its derivatives were utilized in viral vector production (Arena et al., 2019; Pantina et al., 2019; Maldonado et al., 2020). The purpose of this paper is to illustrate the production of viral vectors in HEK293 and its derivatives.
HEK293 Derivatives and Uses
HEK293 cell line was developed by transforming the embryonic kidney cells of humans with Ad5 DNA. Since then, several other types and derivatives of HEK293 have been developed, with HEK293-F and HEK293-T frequently utilized to produce biopharmaceuticals (Raghavan et al., 2019). Other derivatives of HEK293 commonly utilized in the production of recombinant protein include HEK293-6E and HEK293-E, which was created through the genetic expression of the Epstein-Barr nuclear antigen 1 (EBNA-1) that permits the episomal replication of oriP containing plasmids (Lavado-García et al., 2021; Fu et al., 2019; Xiao et al., 2017). Studies show that HEK293-6E exhibits improved cell growth and transient gene expression compared to HEK293-E. Other uses of HEK293 include genetic engineering research on the development of therapeutic viruses and proteins to promote gene therapy.
Ethical Considerations
From an ethical point of view, all human life must be respected and protected from the beginning (Fuenmayor et al., 2017). Over the years, many assumed that HEK293 derived from a medically unnecessary abortion. The church has also reinforced this teaching (Sharipova et al., 2017). However, that cannot be the case. The primary reason is that abortion was illegal in the Netherlands due to the Morality Acts of 1911. Legally, doctors could only perform an abortion if the mother's life was in peril. Otherwise, the practice was strictly prohibited (Abortion in the Netherlands, 2021).
Awards and Accomplishments
The HEK293 has earned its place in the production of biopharmaceutical products (Lecomte et al., 2020; Shahid et al., 2021). Additionally, its ability to grow effortlessly in serum-free suspension culture and transfection amenability make this cell line the most crucial in producing therapeutic products intended for human use, following its human origin (Sharon & Kamen, 2017). At the moment, the production and growth properties of the HEK293 are inferior compared to non-human cell lines, like urine myeloma NSO and CHO cell lines (Ayala-Lujan & Ruiz-Perez, 2018; Le Bec, 2020). However, genetic modifications involved in cellular processes like metabolism, apoptosis, the proliferation of cells, glycosylation, protein folding, and secretion, in addition to vector, media, and bioprocess optimization, have significantly improved the performance of this cell line (Moleirinho et al., 2019; Malm et al., 2020).
Conclusion
HEK293, along with other human cell lines, currently serves as the most valuable niche for developing biopharmaceutical products that need human PTMs (Strobel et al., 2019; Masri et al., 2019). It is also considered the most appropriate cell line for producing recombinant gene therapy vectors like Adeno-associated viruses (AAV) (Abaandou & Shiloach, 2018). However, continued technological advancement and research investments are supposed to further optimize this cell line in producing safe and effective biotherapeutic products.
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