Cell Immortalization

    Tumorigenesis is a complex, multigenic, and multistage process in which oncogenes and tumor suppressor genes play distinct roles. At present, many mysteries surrounding the mechanisms of tumorigenesis remain unsolved, and much research is unable to fully elucidate the entire process. Therefore, many of our research projects require the establishment of immortalized cell lines.

    Cell immortalization refers to the process by which cells, during in vitro culture, avoid the normal aging and death associated with cell passage—either due to intrinsic genetic changes or various external stimuli—thereby enabling long-term passage and indefinite division and proliferation.

    We have summarized several current mechanisms of cell immortalization:

1. Radiation

    This method generally involves exposing cells to radiation, which induces chromosomal rearrangements and suppresses the expression of tumor suppressor genes. This disrupts the normal cellular senescence program, enabling unlimited proliferation. However, this method is rarely used due to its high reliance on chance and the significant wastage of cells, making it not worth the effort.

2. Telomeres and Telomerase Activation

    Telomeres play a role in maintaining chromosomal stability and position, preventing chromosomal degradation. In short, they are a “miracle cure” against aging, and telomerase acts as the catalyst—a reverse transcriptase that catalyzes telomere replication and increases telomere length. However, telomerase is scarce in normal primary cells, and the hTERT gene, as the catalytic subunit of telomerase, is naturally linked to this process. Achieving immortality through the expression of the hTERT gene has thus become a key method. This approach is widely used because it is precise and straightforward.

3. Viral Infection

    The viral infection method alters normal genes, enabling cells to survive two lethal phases and thereby achieve unlimited proliferation. The most commonly used virus is SV40, though others include EB virus, HPV, and so on. The mechanism of action of these viruses is relatively complex, but the ultimate goal is achieved by inhibiting the expression of tumor suppressor genes. This method is also a commonly used mechanism and is a viable option for those concerned about cost.

4. Oncogenes and Tumor Suppressor Genes

    All eukaryotic cells contain oncogenes and tumor suppressor genes. c-myc was the first oncogene to be discovered; the protein transcribed and translated from it can indirectly promote the rapid and efficient expression of telomerase mRNA, thereby activating telomerase activity. Conversely, downregulation of tumor suppressor genes can produce similar effects.

    All eukaryotic cells contain oncogenes and tumor suppressor genes. c-myc was the first oncogene to be discovered; the protein produced by its transcription and translation can indirectly promote the rapid and efficient expression of telomerase mRNA, thereby activating telomerase activity. Conversely, downregulation of tumor suppressor genes can produce similar effects.

Several methods for cell immortalization at KMD Bioscience:

-- Simian Virus 40 (SV40) Cell Immortalization System

-- hTERT Cell Immortalization System

-- MycT58A Cell Immortalization System

-- RasV12 Cell Immortalization System