Exploring the Potential Application of Short Non-Coding RNA-Based Genetic Circuits in Chinese Hamster Ovary Cells

Enhancing protein production and growth in chinese hamster ovary cells through miR-107 overexpression

Chinese Hamster Ovary (CHO) cells are widely employed as host cells for biopharmaceutical production. The manufacturing of biopharmaceuticals poses several challenges, including restricted growth potential and inadequate productivity of the host cells. MicroRNAs play a crucial role in regulating gene expression and are considered highly promising tools for cell engineering to enhance protein production. Our study aimed to evaluate the effects of miR-107, which is recognized as an onco-miR, on erythropoietin-producing CHO cells (CHO-hEPO). To assess the impact of miR-107 on CHO cells, a DNA plasmid containing miR-107 was introduced to CHO-hEPO cells through transfection. Cell proliferation and viability were assessed using the trypan blue dye exclusion method. Cell cycle analysis was conducted by utilizing propidium iodide (PI) staining. The quantification of EPO was determined using an immunoassay test. Moreover, the impact of miR-107 on the expression of downstream target genes was evaluated using qRT-PCR. Our findings highlight and underscore the substantial impact of transient miR-107 overexpression, which led to a remarkable 2.7-fold increase in EPO titers and a significant 1.6-fold increase in the specific productivity of CHO cells (p < 0.01). Furthermore, this intervention resulted in significant enhancements in cell viability and growth rate (p < 0.05). Intriguingly, the overexpression of miR‑107 was linked to the downregulation of LATS2, PTEN, and TSC1 genes while concurrently driving upregulation in transcript levels of MYC, YAP, mTOR, and S6K genes within transgenic CHO cells. In conclusion, this study collectively underscores the feasibility of utilizing cancer-associated miRNAs as a powerful tool for CHO cell engineering. However, more in-depth exploration is warranted to unravel the precise molecular intricacies of miR-107's effects in the context of CHO cells.

Synthetic biology approaches for dynamic CHO cell engineering

Fed-batch culture of Chinese hamster ovary (CHO) cells remains the most commonly used method for producing biopharmaceuticals. Static CHO cell-line engineering approaches have incrementally improved productivity, growth and product quality through permanent knockout of genes with a negative impact on production, or constitutive overexpression of genes with a positive impact. However, during fed-batch culture, conditions (such as nutrient availability) are continually changing. Therefore, traits that are most beneficial during early-phase culture (such as high growth rate) may be less desirable in late phase. Unlike with static approaches, dynamic cell line engineering strategies can optimise such traits by implementing synthetic sense-and-respond programmes. Here, we review emerging synthetic biology tools that can be used to build dynamic, self-regulating CHO cells, capable of detecting intra-/extracellular cues and generating user-defined responses tailored to the stage-specific needs of the production process.