Genome Amplification and Altered Transcriptome Aid in Survival and Enhanced Protein Secretion in...

Area of Science:

• Biotechnology
• Cell Biology
• Molecular Biology

Background:

• Chinese Hamster Ovary (CHO) cells are crucial for biotherapeutic production.
• Enhancing cellular productivity in CHO cells is an ongoing challenge.
• Adaptive laboratory evolution (ALE) combined with omics analysis offers a strategy for host cell line engineering.

Purpose of the Study:

• To enhance the productivity of CHO cells using ALE.
• To investigate the molecular mechanisms underlying increased protein secretion in adapted cells.

Main Methods:

• CHOK1 cells were adapted to tunicamycin (TM), an endoplasmic reticulum (ER) stressor.
• Transcriptomic analysis and whole genome sequencing were performed on adapted cells.
• Transient expression of SEAP was used to assess specific productivity.

Main Results:

• TM-adapted cells exhibited an 8-fold increase in TM resistance and enlarged ER.
• Per-cell secretion rate of total protein increased 3- to 4-fold in adapted cells.
• Upregulation of protein processing, ER stress response, and signaling pathway genes was observed.
• Amplification of a chromosome 4 segment, including Dpagt1, was confirmed.
• Adapted cells showed a ~1.4 fold improvement in SEAP specific productivity.

Conclusions:

• ALE is an effective strategy for engineering CHO cells with enhanced protein production.
• Increased protein secretion is linked to transcriptional changes and genomic amplification.
• Adapted cells demonstrate improved productivity for recombinant protein expression.