Advancing Biomedical Research with Cell Line Establishment

Know about cell lines, their types, how they're made, their role in Biomedical research, and the common issues faced during use.

1. Advancing Biomedical Research with Cell Line
Establishment
Cell lines are indispensable resources in biomedical research. They have considerably
accelerated drug discovery by facilitating gene therapy, disease modeling, and drug
screening. They are an effective platform for research at the cellular and genetic levels.
Technological advancements such as electron microscopy, sequencing, and three-
dimensional culture have further deepened our knowledge base. The immense
contribution of cells in biomedical research has prompted their generation. However, the
process of cell line establishment is complex and demands meticulous handling.
Cell Line- Primary vs Immortalized 
The first cell line was Hela cells, extracted from the cervical cancer patient Henrietta
Lacks in the 1950s. Their continuous proliferation in the laboratory distinguished them
from primary cells. In the same decade, Theodore Puck isolated Chinese hamster ovary
(CHO) cells, which also exhibited indefinite growth even while originating from non-
cancerous tissue. The concept of the cell line refers to indefinitely dividing cells.
However, the definition of the term presently extends to the cells that have adapted to
the laboratory environment, showing optimal growth. Therefore, they have been
classified into the following:
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2. Finite Cell Line: Primary cells with a definite life span are named finite lines after
their first subculture. Examples include aortic smooth muscle fiber and liver
fibroblasts.
Continuous Cell Line: These are cells with an indefinite life span and suitable
growth in the in vitro conditions. Their origin can be tumor tissue, non-tumor
tissue, or primary cells transformed in the laboratory, such as Hela, CHO, and
HEK293.
Stem Cell Line: They have the properties of stem cells (self-renewal and
differentiation) and are cultivated in the lab. E.g., MSCs, iPSCs, etc.
Cell Line Establishment Methods
The Cell Line Establishment can be interpreted in two different ways: successfully
cultivating cells outside the tissue or transforming them to express the desired gene.
The former statement applies to cells derived directly from the tissues, and the latter
pertains to cells obtained after the genetic engineering of tissue-derived cells.
Establishment of Tissue-derived Cell Lines
Establishing a tissue-derived line requires minimization of senescence and
contamination at every step of the procedure, from isolation to culture. Tissue
dissociation occurs by mechanical or enzymatic methods. The utilization of the right
enzymes (collagenase, trypsin, and dispase) and their right concentration impact
survival during the isolation process. High intensity of mechanical force or longer
incubation times with enzymes can also lead to damage.
After subsequent filtration and centrifugation of tissue fragments, in vitro culture should
use optimal conditions regarding temperature, pH, and CO2. Additionally, an adequate
medium, including basal medium, serum concentration, antibiotics, and growth factors,
ensures optimal growth and viability. Subculture or passaging also requires delicate
handling. Regular monitoring, timely passaging, change of media, and seeding at a
suitable split ratio prevent damage. Thus, appropriate culture practices can develop cell
lines for in vitro research.
Establishment of Genetically Engineered Cell Line
Gene editing often aims for their immortalization and/or expression of a foreign gene (or
transgene). Transgene expression involves the selection of a suitable vector (plasmid or
virus), incorporating the adequate promoter, adding the gene of interest into it, and
transfecting it into cells (electroporation, lipofection, etc.). Each step has a significant
impact on transfection efficiency. The final step separates the cells with stably integrated
transgene by a suitable selection process.  Immortalization of finite lines usually
employs viral infection and integration of hTERT. Viral infection was first identified in
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3. cancer to induce uncontrolled proliferation. Genes such as SV40 T antigen, HPV E6/E7,
etc., stimulate immortalization. hTERT is an enzyme that maintains telomere length,
thus preventing senescence, resulting in continuous proliferation. 
Characterization
Characterization is vital for in vitro culture research. It ensures the research on the right
population. The evaluation includes analysis of their morphology, growth rate, protein
marker, and functional aspects. Microscopy can estimate size, structure, and damage,
whereas measuring numbers over a period of time can provide a population doubling
time. Flow cytometry can offer additional identification by determining the expression of
cell-specific surface markers. Functional validation involves the evaluation of cell-
specific functions. Short tandem repeat (STR) profiling and karyotyping (to deduce
genetic abnormalities) are essential for the authentication of human cells. Screening for
contamination from microbes or endotoxins is also crucial for the establishment
process. The entire process promotes the purity of population and the reliability of
results.
Challenges
Cell lines are powerful tools for biological research. However, they also face a few
challenges.
With each passage, cells undergo genetic changes, known as genetic drift. It can
present as varying growth rates or phenotypes. It can alter the study’s findings.
Cross-contamination is another limitation. There have been many reports of
scientists developing a cell line in the lab only to find it contaminated with faster-
growing cells.
Misidentification has also been observed during the establishment process. It
occurs due to inappropriate labeling, handling, and characterizing.
Continuous cell lines are suitable for cancer research. However, the utility of this data
for primary cells has little physiological relevance. Similarly, genetically engineered cell
lines do not incorporate the tissue properties, restricting their use.
Use of Cell Cultures in Biomedical Research
Regenerative Medicine: Stem cell lines have promoted Biomedical research in
regenerative medicine with regard to studying stemness and exploring their role
in therapy. They are beneficial in delineating developmental pathways for tissue
formation. It has led to discovering factors for dedifferentiation to generate
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4. induced pluripotent stem cells. Their organoids have therapeutic potential and
assist in elucidating signaling pathways.
Cancer Research: Continuous cell lines have demonstrated their potential in
cancer research. They have enabled finding the pathways that lead to the
transformation into cancer cells. These pathways provide targets for therapy. For
example, the discovery of PDL1 expression in cancer resulting in immune
invasion has led to the formulation of PDLI antibodies. Similarly, the significance
of vessel development in the tumor microenvironment has created anti-VEGF
therapies.
Manufacturing Biological Products: Several biological products are used in
therapeutics, such as hormones, antibodies, vaccines, biosimilars, etc. These
were manufactured in animal models, compromising the product’s purity.
Genetically engineered cell lines integrate the gene for these therapeutics and
generate the product at a relatively low cost while providing industrial-level scale-
up without affecting quality.
Conclusion
Cell lines have unlocked substantial information and widened our horizons from cancer
research to regenerative medicine. Establishing more such lines has elevated the Level
of Biomedical Research. It has facilitated groundbreaking discoveries and drug
development. Inadequate characterization and contamination remain a hurdle in
acquiring reliable data. Kosheeka has a wide inventory of cells in its store that has been
robustly characterized and stringently tested to add credibility to your results.
FAQ’s
Q – What are cell lines?
These are the cells that can be cultivated outside the body and in an artificial laboratory
environment.
Q – What is the difference between a finite and continuous cell line?
The former have a definite life span and are obtained from primary cells whereas the
latter show unlimited proliferation and can belong to cancer and non-cancer tissue.
Q – What is the purpose of a genetically transformed cell line?
These cells can be used to identify the effects of gene addition or deletion. They are
also useful in manufacturing biosimilars.
Q – What are the challenges in cell line establishment?
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5. Misidentification of cells, genetic drift, and cross-contamination are few challenges in
the establishment process.
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