Cell Transformation and Immortalization

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the definition of transformation of cultured cells?

A spontaneous or induced permanent phenotypic change resulting from a heritable change in DNA and gene expression.

What are the three major classes of phenotypic change associated with transformation?

Immortalization, Aberrant growth control, Malignancy (correct)

Cell division, Apoptosis, Senescence

Genetic instability, DNA repair, Protein synthesis

Differentiation, Metastasis, Proliferation

Immortalization refers to the acquisition of an infinite life span by cells.

True

What is aberrant growth control in the context of transformation?

The loss of contact inhibition of cell motility, density limitation of cell proliferation, and anchorage dependence. Signup and view all the answers

Malignancy is characterized by the growth of invasive tumors in vitro.

False Signup and view all the answers

What is the primary reason for using immortalized cell lines?

To provide a consistent and inexhaustible source of cells for research purposes. Signup and view all the answers

What are two major examples of common immortalized cell lines?

All of the above Signup and view all the answers

What is a major advantage of using immortalized cell lines?

All of the above Signup and view all the answers

What is the SV40 LT gene?

A viral gene often used to induce immortalization in cultured cells. Signup and view all the answers

How does the T antigen influence cell cycle control?

It binds to the p53 protein, a key tumor suppressor, preventing it from halting the cell cycle in response to DNA damage. Signup and view all the answers

Immortalization using viral genes like SV40 LT can lead to an increase in genomic instability.

True Signup and view all the answers

What is the primary function of a biosafety cabinet in a tissue culture laboratory?

To protect the operator and the surrounding environment Signup and view all the answers

Which factor is NOT considered when choosing a culture vessel for cell cultures?

Color of the vessel Signup and view all the answers

What is the main advantage of using poly-D-lysine (PDL) coated flasks?

They ensure cell attachment for primary cells that struggle to grow on surfaces. Signup and view all the answers

Which component of a tissue culture facility is essential for maintaining a controlled environment?

Heating, ventilation, and air conditioning (HVAC) system Signup and view all the answers

Which type of air filter is typically used in laminar airflow cabinets?

High efficiency particulate air (HEPA) filter Signup and view all the answers

Which of the following materials is NOT a recommended interior finish for a tissue culture laboratory?

Wooden fixtures Signup and view all the answers

What role does the CO2 incubator play in a tissue culture facility?

Regulates CO2 levels essential for cell growth Signup and view all the answers

What type of cells do multi-well plates typically accommodate?

Any type, depending on experimental needs Signup and view all the answers

What role do glutamine and glutamate serve in cell culture media?

They serve as sources of energy and carbon. Signup and view all the answers

Which vitamin is NOT typically found in Eagle’s MEM medium?

Vitamin A Signup and view all the answers

What is a primary advantage of using serum in cell culture medium?

It supplies specific growth factors essential for cell proliferation. Signup and view all the answers

What is a significant disadvantage of using serum in cell culture media?

It introduces batch-to-batch variation in compositions. Signup and view all the answers

Which mineral found in serum is important for promoting cell attachment?

Calcium (Ca2+) Signup and view all the answers

Polyamine oxidase in serum reacts with which substances to form cytotoxic compounds?

Polyamines Signup and view all the answers

How does one of the benefits of cell culture aid in biological research?

By allowing researchers to alter environmental factors to study their effects. Signup and view all the answers

What is a common limitation associated with the use of fetal calf serum in cell culture?

It presents a high risk of contamination with pathogens. Signup and view all the answers

What is the primary role of phenol red when added to balanced salt solutions?

To check pH variations Signup and view all the answers

What is a primary source of contamination in cell culture?

Airborne particles laden with microorganisms Signup and view all the answers

Which serum is most commonly used for cell culture due to its rich composition?

Fetal bovine serum (FBS) Signup and view all the answers

Why is it important to screen batches of serum used in cell culture?

To assess serum's ability to support cell growth Signup and view all the answers

Which of the following is NOT a component of culture medium for animal cells?

Heavy metals Signup and view all the answers

What defines artificial culture media?

Has a designed composition to meet nutrient needs Signup and view all the answers

During the development of complete culture media, what did Eagle focus on determining?

The nutrient requirements for mammalian cell cultures Signup and view all the answers

What is essential for maintaining proper culture conditions for animal cells?

Controlled temperature and appropriate growth medium Signup and view all the answers

What is the purpose of heat inactivating serum at 56º C?

To eliminate immune factors that may harm cells Signup and view all the answers

What essential components must be added to the medium for optimal cell culture?

Both essential and non-essential amino acids Signup and view all the answers

Which factor is important for cell attachment in culture?

The presence of a suitable substrate Signup and view all the answers

Which of the following is NOT a type of balanced salt solution?

FBS Signup and view all the answers

What is the purpose of using serum in cell culture medium?

To provide growth factors and hormones Signup and view all the answers

What is the significance of serum in basal media for cell cultures?

It serves as a source of hormones and growth factors Signup and view all the answers

Which characteristic does NOT apply to artificial culture media?

Sterilization is optional Signup and view all the answers

What defines natural media in cell culture?

Derived from biological resources like serum or tissue extracts Signup and view all the answers

What is the desirable pH range for culture media?

7.0 - 7.4 Signup and view all the answers

How does the carbonate-bicarbonate buffer system affect pH?

It maintains pH by reacting with hydrogen ions. Signup and view all the answers

What is a common outcome of exposing mammalian cells to higher oxygen concentrations?

High oxidative stress that adversely affects the cells Signup and view all the answers

What role does serum supplementation play in culture media?

It contains vital antioxidants that relieve oxidative stress. Signup and view all the answers

Which of the following components can be added to Balanced Salt Solutions (BSS)?

Glucose and HEPES Signup and view all the answers

What is the significance of the phenol red indicator in culture media?

It serves as a pH indicator by changing color. Signup and view all the answers

What defines a Balanced Salt Solution (BSS)?

Solutions containing inorganic salts with similar composition to body fluids. Signup and view all the answers

What effect does increasing the CO2 concentration in the gas phase have on culture media?

It increases the concentration of carbonic acid and decreases pH. Signup and view all the answers

Study Notes

Transformation and Immortalization of Cultured Cells

Transformation of cultured cells is a spontaneous or induced permanent phenotypic change. This change results from a heritable alteration in DNA and gene expression.
Transformation is linked to genetic instability and involves three main phenotypic alterations:
- Immortalization: The acquisition of an unlimited lifespan,
- Aberrant growth control: Loss of contact inhibition, density limitation of cell proliferation (and anchorage dependence), and abnormal cell motility.
- Malignancy: Evidenced by the growth of invasive tumors in vivo. The term "transformation" encompasses all three processes.

Immortalization

Immortalized cell lines are either:
- Tumorous: They don't stop dividing,
- Artificially manipulated: They can proliferate indefinitely.
Immortalized cells continuously divide, filling the culture dish. Scientists "split" or "passage" the cells to create space for continued growth, transferring fractions of proliferating cells to new containers.
Common immortalized cell lines include human embryonic kidney 293T (HEK-293T) cells and HeLa cells.

Immortalization: Advantages and Disadvantages

Advantages:*
Well-characterized and homogeneous, with genetically identical cells, allowing for consistent and reproducible results.
Easier to culture than primary cells.
Grow quickly and continuously.
Disadvantages:*
Cannot be considered normal cells in in vivo conditions.
Cell characteristics can change and become significantly different from normal cells after several passages.

Primary Cells

Advantages:*
Similar chromosome number as the parent tissue.
Possess unique biochemical properties that reflect the parent tissue (e.g., growth factors and hormone secretions).
Serve as excellent experimental models for in vivo situations.
Disadvantages:*
Finite lifespan and a limited number of cell divisions.
Considerable cell-to-cell variability in populations and between preparations.
Difficult to maintain and can be challenging to obtain, due mainly to donor availability issues.

Immortalized Cells

Advantages:*
Exhibit a tendency to grow faster and can reach higher cell densities compared to primary cells.
Often characterized by a uniform cell type (mostly clonal).
Typically derived from the same donor, decreasing batch-to-batch variation.
Maintain most cellular characteristics from their parent cell.
Save money and time for prolonged projects.
Useful for in vitro experiments.
Disadvantages:*
May differentiate over time in culture.
Cellular behavior in vitro might not perfectly represent in vivo scenarios
Potential alterations in cell phenotype or function.

Immortalization with Viral Genes

The SV40 LT gene is frequently used to induce immortalization.
The LT gene's product (T antigen) interferes with the cell cycle regulation, notably binding to the p53 protein, overriding the cell cycle, which makes the cells proliferate indefinitely.
This process extends the proliferative lifespan and restricts the DNA surveillance mechanisms, notably the p53 gene activity, thereby allowing for increased genomic instability and promoting further mutations like telomerase upregulation or downregulation of telomerase inhibitors.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores the processes of cell transformation and immortalization, focusing on the genetic changes that lead to distinct phenotypic characteristics in cultured cells. Understand the implications of these changes in cell biology, particularly in relation to tumor growth and cell proliferation. Test your knowledge on how these concepts are applied in scientific research.