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Published on: May 21, 2020
Proteasome Inhibition Amplifies Endoplasmic Reticulum (ER) Stress Responses: Comparative Proteomics of Chinese
Christiana-Kondylo Sideri1,2, David Ryan1,2, Michael Henry1
1Life Sciences Institute, Dublin City University, D09 K20V Dublin, Ireland.
Abstract:
Chinese hamster ovary (CHO) cells are widely utilised in the biopharmaceutical industry to produce therapeutic proteins. Understanding the mechanisms of endoplasmic reticulum (ER) stress and its interplay with protein degradation pathways remains pivotal for improving production efficiency and product quality. In this study, we investigated the proteomic responses of CHO-K1 (non-producer), CHO DP-12 (IgG-producer), and NISTCHO (IgG-producer) cell lines under ER stress induced by a combination of the proteasome inhibitor MG132 and the glycosylation inhibitor tunicamycin. Viability, cell growth, and IgG titre were measured after 24 h, 48 h, and 72 h of treatment and the 48 h timepoint was used for the comparative analysis of the proteomic data across the three cell lines. Proteasome inhibition with MG132 intensified ER stress and altered ER-associated protein degradation (ERAD). Combined tunicamycin + MG132 treatment was associated with cell line-specific proteomic changes: NISTCHO upregulated ER translocation and glycoprotein quality control proteins (SSR4, SEC24C, UGGT1), CHO DP-12 activated redox/disulfide regulators (DNAJC10, CAPN1), while CHO-K1 showed broad proteome shifts, suggesting differences in baseline stress handling. These findings provide mechanistic insights into ER stress and protein quality control in CHO cells, offering a foundation for strategies to enhance cell line robustness and optimise biopharmaceutical production.
Insights
Investigating endoplasmic reticulum (ER) stress in Chinese hamster ovary (CHO) cells reveals cell-specific proteomic responses to combined drug treatments, impacting protein production and quality control mechanisms.
Area of Science:
- Biotechnology
- Cell Biology
- Proteomics
Background:
- Chinese hamster ovary (CHO) cells are crucial for biopharmaceutical production of therapeutic proteins.
- Endoplasmic reticulum (ER) stress and protein degradation pathways significantly influence production efficiency and protein quality.
- Understanding these mechanisms is vital for optimizing biomanufacturing processes.
Purpose of the Study:
- To investigate the proteomic responses of different CHO cell lines (CHO-K1, CHO DP-12, NISTCHO) to ER stress.
- To analyze the interplay between ER stress and protein degradation pathways under combined proteasome and glycosylation inhibition.
- To identify cell line-specific adaptations to ER stress for improved biopharmaceutical production.
Main Methods:
- Induction of ER stress in CHO-K1, CHO DP-12, and NISTCHO cell lines using MG132 (proteasome inhibitor) and tunicamycin (glycosylation inhibitor).
- Measurement of cell viability, growth, and IgG titre at 24, 48, and 72 hours post-treatment.
- Comparative proteomic analysis at the 48-hour timepoint to identify protein expression changes.
Main Results:
- Proteasome inhibition with MG132 exacerbated ER stress and altered ER-associated protein degradation (ERAD).
- Combined tunicamycin + MG132 treatment induced distinct proteomic profiles in each cell line.
- NISTCHO cells upregulated ER translocation and glycoprotein quality control proteins; CHO DP-12 cells activated redox/disulfide regulators; CHO-K1 cells exhibited broad proteome shifts.
Conclusions:
- Cell line-specific proteomic alterations occur under combined ER stress conditions in CHO cells.
- Distinct cellular responses suggest varying baseline stress handling capabilities among CHO cell lines.
- These findings provide mechanistic insights for enhancing CHO cell line robustness and optimizing biopharmaceutical manufacturing.
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