Animal Cell Culture Basics

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Questions and Answers

What does animal cell culture primarily involve?

Growing animal cells in vitro outside their natural environment (correct)

Creating artificial organs for transplantation

Performing surgeries on live animals

Growing cells within their natural habitat

Which type of tissue culture involves placing a fragment of tissue at a glass or plastic–liquid interface?

Suspension culture

Organ culture

Primary explant culture (correct)

Adherent monolayer culture

Which statement correctly describes organ culture?

Cells proliferate as a monolayer on solid substrates

The entire organs are cultured retaining architectural characteristics (correct)

Tissues are mixed to improve migration

Only cell suspensions are allowed without attachment

Which is NOT a type of animal cell culture?

Chemical culture Signup and view all the answers

What are the two morphological forms that cell cultures take?

Suspension and adherent Signup and view all the answers

What is the primary means of promoting migration in primary explant culture?

Attachment to solid substrate Signup and view all the answers

What does a liquid–gas interface in organ culture favor?

Retention of three-dimensional shape Signup and view all the answers

Which of the following is considered an advantage of animal cell culture?

Controlled experimental conditions Signup and view all the answers

What is one advantage of using cell culture in biotechnology?

It facilitates the identification of cell types based on appearance. Signup and view all the answers

Which of the following is a disadvantage of animal cell culture techniques?

They require expensive equipment and trained personnel. Signup and view all the answers

What effect does the subculture of animal cell lines often have?

It might lead to differentiated properties compared to the original strain. Signup and view all the answers

Which type of cells is a common example of a cell line derived from solid tissues?

HeLa cells Signup and view all the answers

Why is animal cell culture preferred for testing drugs and compounds?

It facilitates observation of effects on specific cell types. Signup and view all the answers

What is a common problem associated with animal cell cultures?

They can be easily infected by mycoplasma and viruses. Signup and view all the answers

What kind of cells are the MCF-7 cell line derived from?

Breast cancer cells Signup and view all the answers

Which of the following is a key characteristic of endothelial cells?

They line the blood vessels in the body. Signup and view all the answers

What is one of the main applications of cell culture in drug development?

Drug screening and development Signup and view all the answers

Which condition often leads to instability in cultured cells?

Aneuploidy chromosomal constitution Signup and view all the answers

What is a significant limitation of cells grown in vitro compared to in vivo?

Lack of growth hormones Signup and view all the answers

What allows the study of differences between cancer cells and normal cells?

Disparities in metabolism and growth rate Signup and view all the answers

What effect does the absence of 3D scaffolding have on cultured cells?

Reduces cell interactions Signup and view all the answers

How can normal cells be transformed into cancer cells?

By using certain chemicals, viruses, and radiation Signup and view all the answers

What is a consequence of reduced cell interactions in vitro?

Altered gene expression patterns Signup and view all the answers

What role do cultured cancer cells serve in research?

They assist in studying drug efficiency against cancer treatment. Signup and view all the answers

What role do adhesion molecules play in the cytoskeleton?

They attach to the cytoskeleton and facilitate cell surface signalling. Signup and view all the answers

Which type of intercellular junction is responsible for preventing leakage of extracellular fluid?

Tight junctions Signup and view all the answers

What primarily determines the constituents of the extracellular matrix (ECM)?

The type of cell producing the ECM. Signup and view all the answers

Which junction type holds epithelial cells together?

Desmosomes Signup and view all the answers

What is a significant characteristic of fibroblasts in culture?

They are most motile at low cell density. Signup and view all the answers

What phase follows the lag phase in cell culture growth characteristics?

Log phase Signup and view all the answers

What does the term 'senescence' refer to in a cellular context?

A permanent growth arrest after a finite number of cell divisions. Signup and view all the answers

Which of the following factors is associated with the transformation of cells in culture?

Shortening of telomeres. Signup and view all the answers

What occurs to the telomere region during DNA replication?

It is shortened Signup and view all the answers

What defines a cell line derived from primary culture?

It can be further propagated and subcultured Signup and view all the answers

Which term describes the process when cells acquire infinite lifespan?

Immortalization Signup and view all the answers

Which of the following is a characteristic of continuous cell lines?

Ability to grow in semisolid media Signup and view all the answers

What is one outcome of the gradual predominance of rapidly proliferating cells during subculturing?

Dilution of non-proliferating cells Signup and view all the answers

What is the consequence of p53 gene mutation or deletion in cell lines?

Transformation into a continuous cell line Signup and view all the answers

What is aneuploidy associated with in continuous cell lines?

Variations in chromosome numbers Signup and view all the answers

Which trait is NOT typically associated with malignant transformations in cell cultures?

Inability to grow in semisolid media Signup and view all the answers

What is the role of positive acting factors in cell proliferation?

To promote cell cycle progression Signup and view all the answers

Which of the following factors negatively regulates cell proliferation?

Transforming growth factor (TGF) Signup and view all the answers

Which of the following conditions would most likely promote cell proliferation?

Low cell density with mitogens Signup and view all the answers

What is the primary difference between dedifferentiation and deadaptation?

Dedifferentiation results in a more primitive phenotype, while deadaptation suppresses specific phenotypes. Signup and view all the answers

Which of the following factors can inhibit cell proliferation through contact inhibition?

High confluency Signup and view all the answers

What is the effect of the Rb gene product in the cell cycle?

Prevents progression at checkpoints Signup and view all the answers

Which growth factors are associated with promoting cell proliferation?

Fibroblast Growth Factor (FGF) Signup and view all the answers

What characterizes dedifferentiation in cells?

Cells lose their ability to differentiate Signup and view all the answers

Study Notes

Animal Cell Culture Introduction

Animal cell culture is the growth of tissues or cells separated from an organism.
In vitro culture maintains and/or proliferates cells, tissues, or organs.
Liquid, semi-solid, or solid growth media (broth or agar) are used in this process.
Growth occurs outside the natural environment of the animal cells, in controlled conditions.

Topics Outline

What is animal cell culture?
Historical background of animal cell culture methods.
Types of tissue culture (e.g., adherent and suspension cultures).
Advantages and limitations of animal cell culture techniques.
Applications of animal cell culture.

What is Animal Cell Culture?

The growth of tissues or cells from an organism, separated from the organism in vitro (outside the organism)
In vitro culture of cells, tissues, or organs to maintain and/ or proliferate
This is done through the use of a liquid, semi-solid, or solid growth medium (broth or agar)
Animal cells are grown in vitro (outside the living organism), in controlled conditions.

Historical Background

1907: Ross Granville achieved the first successful tissue culture in vitro.
1911: Alexis Carrel and Montrose Burrows defined "tissue culture." They established the first cell line using diluted blood plasma.
1920s: Salt solutions were formulated for cell culture specifically.
1940s: Antibiotics began to be used in cell culture.
1960s: Widely available carbon dioxide incubators became readily available.
Development of various culture media and equipment since.
Recent advances include: DNA, methods for isolating cells to be used.

Three Types of Tissue Culture

Adherent cultures: Cells grow in a monolayer attached to a solid substrate.
Suspension cultures: Cells remain suspended in the liquid culture medium.
Explant cultures: Tissue fragments are attached to a substrate, often glass or plastic, to create an interface between the tissue and the liquid medium.

Advantages of Animal Cell Culture

Superior method in biotechnology to alter physiological and physiobiological conditions like pH and temperature
Enable related studies on cell metabolism and the biochemistry of cells, like drug testing
Allows observation of the effects of different compounds (e.g., drugs, proteins) on various cell types under controlled conditions
Provides consistent results if a single cell type is used.

Disadvantages of Animal Cell Culture

Requires trained personnel and aseptic conditions, so it's a costly technique using specialized equipment
The subculture of cells might create differentiated properties compared to the original strain
Results in proportionally very small amounts of recombinant proteins, increasing overall expenses
Contamination with mycoplasma and viruses is frequent and challenging to detect.
Instability of cells due to chromosomal aneuploidy.

Cell Culture Application

Studying normal cell physiology and biochemistry
Investigating the effects of drugs and toxic compounds on cells
Analyzing mutagenesis and carcinogenesis
Drug screening and development
Large-scale manufacturing of biological compounds (vaccines, insulin)
Cancer research, studying differences between cancer and normal cells
Testing the effects of carcinogenic substances
Examining drug and technique effectiveness for cancer treatment

Cell Culture Morphology

Suspension cultures: Cells grow as single cells or small clumps. Derived from blood (leukemia, lymphoma).
Monolayer cultures: Cells grow as a layer attached to a surface. Derived from solid tissues (lungs, kidney, breast, etc). These can include epithelial, neuronal, and fibroblast cells.

Biology of Cultured Cells

The culture environment, characterized by factors like the nature of the substrate, degree of contact with other cells, culture medium (physicochemical and physiological constitution), gas phase, and incubation temperature, profoundly influence cells in vitro.
These factors influence how cells proliferate, migrate, differentiate and undergo apoptosis.
The environment can alter cell function in vitro, compared to in vivo.

Cell Adhesion

Most cells from solid tissues grow as adherent monolayers.
The adhesion is mediated by specific cell surface receptors for molecules in the extracellular matrix (ECM).
Cells spread across the substrate with secretion of ECM protein and proteoglycans.
Cells bind to the matrix via specialized cell receptors.
Glass or plastic surfaces are often treated to provide specific binding interactions.

Cell Adhesion Molecules

Cadherins (Ca2+ dependent): Interactions between homologous cells through adherens junctions or desmosomes.
CAMs (Ca2+ independent): Cell-cell adhesion molecules that interact with integrins.
Integrins: Mediate cell-matrix adhesion and interact with molecules like fibronectin, entactin, laminin, and collagen.
Transmembrane proteoglycans interact with matrix components like proteoglycans and collagens.

Cell Motility

Most cultured cells have the capacity to move.
Fibroblasts are highly motile under standard cell growth conditions, and epithelial cells (monolayers) are less so.

Evolution of Cell Lines

Primary cells have a finite lifespan.
Primary cell culture goes through a lag phase, followed by exponential growth (log phase), a plateau phase, and finally, senescence (the cells stop dividing).
Continuous cell lines can be created from primary cells via transformation or immortalization.
These cells have an indefinite lifespan, meaning they continually divide and grow.

What is Senescence?

Senescence is a state of permanent cell cycle arrest from which cells cells cannot subsequently re-enter the cell cycle.
It is a cellular process that limits cell growth and division.
Senescence is naturally regulated based on aspects like the shortening of telomeres through each replication cycle.

Initiation of Cell Lines

Primary cultures: Derived directly from tissues, with limited capacity for division and time in culture.
Cell lines: Derived from primary cultures through repeated propagation. These can be finite (have a limited time in culture) or continuous (capable of continued growth).

Continuous Cell Lines

Continuous cell lines exhibit alterations like p53 mutation or deletion, overexpression of telomerase, and immortalization.
Their chromosomal numbers are aneuploid (not a normal diploid or tetraploid).
Most cells generally will not transform to become continuous cell lines.

Regulation of Cell Proliferation

Proliferation is governed by factors like the culture environment, growth factors, confluency, and intracellular controls. These mechanisms also regulate normal cells entry into the 'cell cycle'.
Factors promoting include: mitogens such as platelet-derived growth factor (PDGF), epidermal growth factor (EGF), Fibroblast growth factors (FGF).
Factors inhibiting include the density of the cells and TGF. Internal regulatory mechanisms control this process.

Cell Proliferation vs Cell Differentiation

Cell proliferation involves cells growing and dividing, while differentiation involves cells becoming specialized for particular functions.
Normal culture conditions, with low density and presence of mitogens, typically favor proliferation. High density conditions promoting differentiation.

Dedifferentiation

This is the loss of specialized characteristics or traits in a cell line or a cell.
Factors leading to this include inability or problems with differentiation in vitro, and undifferentiated or wrong cell lines outgrowing cells in their normal differentiated states.

Dedifferentiation vs Deadaptation

Dedifferentiation represents cells losing characteristic traits, often an irreversible process.
Deadaptation reflects a reversible loss of phenotype by a change in the cell’s growth environment.

Tissue Retains Function Longer

3D tissue cultures have the advantage of better retaining properties, though often not easily propagated.
Matrigels can be useful for supporting these 3D cultures.

Cell Signaling

Cells communicate through signaling pathways that regulate cell activities such as cell proliferation, migration, apoptosis and more.
These pathways include cell-cell communication and interactions, signaling via cell adhesion molecules, and hormonal stimuli. Autocrine, paracrine and endocrine pathways exist in vivo, but autocrine mechanisms are more likely to operate in vitro.

Checkpoint in Cell Cycle

G1 checkpoint: Cell checks for DNA damage, nutrients, and growth factors to ensure the viability of the cell before it proceeds to the S phase.
G2 checkpoint: Cell checks for DNA replication completeness and any damage or errors.

How Cell Cycle Inhibitors Regulate Cell Proliferation

Cell division is regulated by genes that code for, and regulate cell cycle enzymes. These include cyclins and cyclin-dependent kinases.
Inactivation of these genes and protein products like p53 and Rb proteins can lead to uncontrolled cell growth and division, commonly associated with the development of cancers.

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Description

This quiz explores the fundamentals of animal cell culture, including types of cultures, advantages, and disadvantages. Test your knowledge on the principles that govern this essential area of biotechnology and tissue engineering.