Cell Line Immortalization Techniques in Mammalian Models

Immortalized cell lines form the cornerstone of modern biomedical research by offering a virtually unlimited supply of genetically defined cells for experiments in genetics, toxicology, drug discovery and regenerative medicine. In mammalian systems, the principal barrier to indefinite cell proliferation is replicative senescence, driven by telomere shortening and activation of cell cycle checkpoints. Early approaches exploited viral oncoproteins such as Simian virus 40 (SV40) large T antigen or human papillomavirus E6/E7 to inactivate tumour suppressors and bypass senescence. More refined methods harness the catalytic subunit of telomerase (TERT) to maintain telomere length, often in combination with mutant cell cycle regulators—most notably a cyclin-dependent kinase 4 variant resistant to p16 inhibition (CDK4R24C) together with Cyclin D1. Such combinatorial “K4DT” strategies have proven broadly effective across diverse mammalian species, minimising genomic instability compared to viral proteins alone. Advances in viral vector design and genome-editing tools now enable stable, site-specific introduction of immortalizing factors, while conditional or inducible systems permit temporal control over proliferation. These developments have heightened the physiological relevance of cell models, facilitated conservation of endangered species’ cells and streamlined the production of biologics. As the field moves towards precision immortalization, emphasis falls on preserving native cell phenotype and karyotypic integrity.

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Cell Line Immortalization Techniques in Mammalian Models publication trend

The graph below shows the total number of articles in cell line immortalization techniques in mammalian models across all publications each year (not limited to Nature Index journals).

Technical terms

Replicative senescence: Permanent growth arrest of primary cells after a finite number of divisions, driven by telomere shortening and activation of p53/p16 pathways.

Telomerase reverse transcriptase (TERT): Catalytic enzyme subunit that elongates telomeres, preventing replicative senescence and extending cellular lifespan.

SV40 large T antigen: Viral oncoprotein that binds and inactivates p53 and retinoblastoma proteins, enabling cells to bypass growth arrest.

Cyclin-dependent kinase 4 (CDK4R24C): Mutant form of CDK4 resistant to inhibition by p16, used with Cyclin D1 to drive cell cycle progression past the G1 checkpoint.

Cyclin D1: Regulatory subunit that partners with CDK4 to phosphorylate retinoblastoma protein and promote S-phase entry.

Viral vector: Engineered virus used to deliver genetic material into host cells, commonly employed for stable expression of immortalizing genes.

References

1. Practical Use of Immortalized Cells in Medicine: Current Advances and Future Perspectives. International Journal of Molecular Sciences (2023).
2. Lost in transduction: Critical considerations when using viral vectors. Frontiers in Cell and Developmental Biology (2023).
3. Characterization of Common Minke Whale (Balaenoptera Acutorostrata) Cell Lines Immortalized with the Expression of Cell Cycle Regulators. Advanced Biology (2023).
4. Immortalization of American miniature horse-derived fibroblast by cell cycle regulator with normal karyotype.. PeerJ (2024).
5. Establishment of immortalized Egyptian Rousettus bat cell lines. FEBS Open Bio (2024).