Engineering CHO cell metabolism for growth in galactose
Engineering CHO cell metabolism for growth in galactose
复制标题
改造 CHO 细胞代谢以促进半乳糖生长
作者：
Natalia E. Jiménez;Camila A. Wilkens;Z. Gerdtzen
背景中国仓鼠卵巢(CHO)细胞是工业化生产治疗性蛋白的主要宿主之一，这是因为基因转染、扩增和筛选高产克隆的技术已经成熟。这促使人们寻求不同的策略来提高它们的比生产率，这是减少乳酸和氨等代谢最终产物的方法的关键点之一。使用不同的碳源是解决这一问题的替代方案，因为它们的代谢速度比葡萄糖慢，导致代谢最终产物的产量较低[1]。特别是，人们已经观察到，在葡萄糖和半乳糖存在的情况下，培养物经历了代谢变化，在这种变化中，它们能够重新代谢乳酸。然而，由于与半乳糖结合相关的较慢的新陈代谢，比生长速率降低[2]。此外，细胞不能以半乳糖作为其唯一的碳源[3]。在这项工作中，我们的目的是确定在以葡萄糖和半乳糖为碳源的条件下，延长tPA产生CHO细胞的培养能力的培养条件。此外，我们建议通过过度表达半乳糖激酶(GALK1)来减少次级代谢物的产生，这是半乳糖代谢的一个瓶颈。
Background Chinese hamster ovary (CHO) cells are one of the main hosts for industrial production of therapeutic proteins, owing to well-characterized technologies for gene transfection, amplification, and selection of high-producer clones. This has motivated the search for different strategies for the improvement of their specific productivity being one of the key points for this approaches the reduction of metabolic end-products like lactate and ammonia. The use of different carbon sources has been an alternative solution for this problem, as they are metabolized more slowly than glucose leading to lower production of metabolic end-products [1]. Particularly, it has been observed that cultures in presence of glucose and galactose undergo a metabolic shift in which they are capable of remetabolize lactate. However, the specific growth rate is diminished due to a slower metabolism associated to the incorporation of galactose [2]. In addition, cells are unable to survive with galactose as their unique carbon source [3]. In this work we aim at identifying culture conditions that extend the culture’s viability for tPA producing CHO cells in media with combined glucose and galactose as carbon sources. Furthermore, we propose reducing the production of secondary metabolites by overexpressing galactokinase (GALK1), a bottleneck point in the galactose metabolism.