CHO Cell Genome Stabilization via DNA Repair Gene Restoration
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Solution Overview
Problem
Mammalian cell lines, particularly CHO cells, face instability due to genomic instability, leading to transgene loss and production instability in recombinant protein production, which results in inefficient protein production and high production costs.
Innovation Solution
Reversing mutations or silencing of certain DNA repair genes, such as ATM and PRKDC, to enhance DNA repair mechanisms in CHO cells, thereby improving genome stability and protein production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CHO cells are used for recombinant protein production, then productivity exceeds 10 g/L, but cell line instability causes significant decline in product titer following a few generations in culture
Solution Approach 1:
The patent applies preliminary action by reverting mutations in DNA repair genes (ATM, PRKDC) before production to prevent future genomic instability. This proactive genetic correction ensures cells maintain production capability throughout the manufacturing process, avoiding the typical titer decline that occurs after a few generations in culture.
Solution Approach 2:
The patent changes the genetic parameters of CHO cells by reverting specific mutations in DNA repair genes. This parameter change restores proper DNA repair function, thereby stabilizing the cell line and maintaining high productivity throughout the production cycle without the usual decline in product titer.
2Reliability
If many clones are screened to identify stable producers, then production stability improves, but development time and cost increase significantly
Solution Approach 1:
The patent performs preliminary genetic correction of DNA repair gene mutations before the screening process. This preliminary action ensures that cells inherently possess stable production characteristics, eliminating the need to screen numerous clones to find stable producers and significantly reducing development time.
Solution Approach 2:
The patent extracts and corrects the specific genetic defect (mutations in DNA repair genes) that causes production instability. By removing this root cause, the patent eliminates the need for extensive clone screening, as all corrected cells inherently exhibit stable production characteristics.
3Productivity
If transgene copy number is increased to boost productivity, then protein production increases, but transgene loss accelerates due to genomic instability
Solution Approach 1:
The patent changes the genetic parameters by reverting mutations in DNA repair genes, which restores proper genomic stability. This allows the cell line to maintain high transgene copy numbers and sustain high protein production without the accelerated transgene loss that normally occurs in genomically unstable CHO cells.
Solution Approach 2:
The patent applies beforehand cushioning by correcting DNA repair gene mutations prior to production scaling. This genetic correction creates a buffer against genomic instability, allowing the cell line to tolerate high transgene copy numbers and maintain both high productivity and transgene stability throughout the production process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The approach results in improved double-strand break repair and increased protein product titer, leading to more stable and efficient recombinant protein production.
Implementation Method 1
Loss of chromosomal material and improper chromosome fusions (translocations) are thought to be caused by one particularly critical mutation type, double-strand breaks (DSBs). DSBs occur from ionizing radiation, attack by free radicals, or collapsed DNA replication forks. Due to their potential fatal outcome on chromosomal integrity, eukaryotes are equipped with a complex set of molecular mechanisms to repair DSBs with little or no sequence loss.
Data Source
AI summary
The invention provides gene targets whose restoration leads to genome stabilization in host cells, such as Chinese Hamster Ovary (CHO) cells. Many DNA repair genes are mutated in CHO cells which compromises their ability to repair naturally occurring DNA damage, in particular double-strand breaks (DSBs). Unrepaired DSBs can give rise to chromosomal instability which, in turn, can lead to loss of transgenes from the genome. As a consequence, protein titer can drop significantly, rendering protein production unprofitable. The invention provides a set of mutated DNA repair genes whose restoration yields significant improvement in DSB repair, genome stability, and protein titer.