Name: how cancer cells survive and spread
Uploaded: 2021-04-07T12:12:02.000Z
Duration: 2 min 53 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Life Sciences

from-molecules-to-organisms-structures-and-processes

From Molecules To Organisms: Structures And Processes

HS-LS1-4

Adaptive Mechanisms in Cancer Cells

Cancer cells exhibit a mutator phenotype characterized by defective DNA repair mechanisms that lead to higher than normal mutation rates. Their tolerance to mutations even in the critical cell cycle genes confer them with survival advantages over normal cells.&#160;
For example, normal cells stop dividing once they contact another cell, in a phenomenon known as contact inhibition. However, some cells can mutate to overcome contact inhibition and pile up on top of each other, forming a tumor mass.&#160;
Nonetheless, these tumor cells cannot continue to proliferate forever. At some point, they may undergo replicative cell senescence, a phenomenon where cells stop dividing after a certain number of cell divisions.&#160;
Thus, some tumor cells mutate further to overcome this hurdle and become cancerous. First, they increase their rate of cell division to compensate for the loss of cells due to cell senescence. Secondly, they can evade apoptosis, resulting in the prolonged survival of old and damaged cells.
The tumor grows, the cells in the interior of a large tumor receive less oxygen - a phenomenon called hypoxia. This limits the ability of the cells to grow and can trigger cell necrosis inside the

adaptive mechanisms in cancer cells

Cancer cells accumulate genetic changes at an abnormally rapid rate due to the defects in the DNA repair mechanisms. From an evolutionary perspective, such genetic instability is advantageous for cancer development. Mutant cell lines accumulate a series of beneficial mutations that contribute to their progression into cancer.
Some of the advantages that cancer cells have on normal cells include - enhanced ability to divide without terminally differentiating, induce new blood vessel formation, overcome contact inhibition to form a large mass of cells, escape apoptosis, and invade and colonize other tissues. Cancer cells also have increased tolerance to mutations and altered metabolism for rapid energy production.
<h4>Cancer cells and telomeres</h4>
Cellular senescence generally depends on the progressive shortening of the ends of chromosomes called telomeres. Cells produce a reverse transcriptase enzyme called telomerase that prevents the telomere shortening during successive cell division cycles. However, after a certain number of cell divisions, telomerase enzymes&#39; expression decreases, pushing the cell towards apoptosis. Cancer cells overcome this selection pressure by overexpressing the telomerase enzyme, allowing cells to continue the cell division and delay cellular senescence.
<h4>Hypoxia </h4>
Rapidly growing tumors must be accompanied by rapid vasculature to provide oxygen and nutrients to all the tumor cells. Due to the diffusion limit of oxygen, the inner core of a large tumor is deficient in oxygen and, therefore, has a hypoxic environment. At the same time, the outer layer of cells that is enriched with blood vessels continues to proliferate. The inner core cells slowly start losing viability due to the lack of oxygen, creating a gradient of cell viability across the tumor mass. Interestingly, the hypoxic cells show higher resistance to radio and chemo-therapy due to reduced reactive oxygen species production and altered metabolism.
Also, hypoxic conditions induce the expression of hypoxia-inducible factors (HIF), which modulate the expression of a broad range of genes involved in angiogenesis, cell survival and death, metabolism, cell-cell adhesion, extracellular matrix remodeling, migration, and metastasis.

Cancer cells accumulate genetic changes at an abnormally rapid rate due to the defects in the DNA repair mechanisms. From an evolutionary perspective, ...

Education

JoVE Core

Molecular Biology

Unit 2

Cancer

KEY TERMS AND CONCEPTS

how cancer cells survive and spread

Cancer cells survive and spread by gaining genetic changes that help them grow faster than normal cells. These changes build up quickly because defects in DNA repair let mutations appear at an unusually high rate. From an evolutionary point of view, this genetic instability gives cancer cells an advantage as they develop.

As mutant cell lines keep changing, they collect helpful mutations that support cancer progression. These cells can divide without fully differentiating, form large cell masses by overcoming contact inhibition, and escape apoptosis, which is programmed cell death. They can also invade other tissues and colonize them. Cancer cells often show increased tolerance to mutations and altered metabolism that supports rapid energy production.

Telomeres also play a major role in cancer cell growth. Telomeres are the ends of chromosomes, and they normally shorten each time a cell divides. Cells make an enzyme called telomerase, a reverse transcriptase, to prevent this shortening during repeated cell divisions. After many divisions, telomerase expression usually decreases and pushes the cell toward apoptosis. Cancer cells avoid this limit by overexpressing telomerase, which helps them keep dividing and delays cellular senescence, or cell aging.

Rapidly growing tumors also need a steady supply of oxygen and nutrients. Because oxygen cannot diffuse very far, the center of a large tumor becomes hypoxic, meaning low in oxygen. The outer cells, which are closer to blood vessels, keep dividing, while inner cells slowly lose viability. Hypoxic cells are often more resistant to radiotherapy and chemotherapy because they produce less reactive oxygen species and have altered metabolism. Low oxygen also activates hypoxia-inducible factors, or HIF, which change the expression of genes involved in angiogenesis, cell survival and death, metabolism, cell adhesion, extracellular matrix remodeling, migration, and metastasis.

How Cancer Cells Survive and Spread

what is cancer?

Cancer Cells and How They Spread

Cancer cells and how they spread are explained through the normal behavior of cells and tissues. In a healthy body, cells must coordinate carefully. They rest, grow, divide, differentiate, or die in ways that support the organism. Cancer begins when this control breaks down. Cells divide without stopping and invade nearby tissues or organs. Cancer cells show two heritable traits. They reproduce against normal limits on cell growth and division, and they invade and colonize other cells and...

cancers originate from somatic mutations in a single cell

cancers-originate-from-somatic-mutations-in-a-single-cell

How Mutations Drive Cancer Growth

Cancer develops when mutations change the genes that control the cell cycle and let healthy cells keep dividing. A cancer can begin from a single mutation in one starting cell. As that cell line keeps growing, it can collect more mutations and eventually become malignant. One example is chronic myelogenous leukemia, or CML. It often begins as a non-lethal rise in white blood cells and then grows worse over several years before becoming life-threatening. This shows how cancer can progress step...

tumor progression

From Polyp to Metastatic Cancer

Tumor progression is the stepwise change that can turn an early tumor into a more aggressive and malignant cancer. Foulds first described this pattern in the 1950s. Colon cancer is one of the best-known examples, because researchers can follow its changes over time. In colon cells, an early mutation in the APC gene can create a small growth on the colon wall called a polyp. Over time, this polyp may grow into a benign, pre-cancerous tumor. Later mutations in the K-ras and p53 genes can push...

Cancer cells survive and spread by gaining genetic changes that help them grow faster than normal cells. These changes build up quickly because defects in DNA repair let mutations appear at an unusually high rate. From an evolutionary point of view, this genetic instability gives cancer cells an advantage as they develop. As mutant cell lines keep changing, they collect helpful mutations that support cancer progression. These cells can divide without fully differentiating, form large cell...

the tumor microenvironment

How Tumors Remodel Their Surroundings

Tumors remodel the local tissue environment to support cancer growth. This surrounding area is called the stroma. It includes several cell types, a basal membrane, and blood vessels. As normal cells mutate and become cancer cells, the nearby environment changes with them. The tumor microenvironment, or TME, is made of the developing tumor and the stromal cells around it. Communication between cancer cells and these surrounding cells is important because it disrupts normal tissue balance and...

metastasis

How Cancer Cells Spread to New Sites

Metastasis is the spread of cancer cells from one part of the body to another. Cancer cells can move through blood vessels, called hematogenous spread, or through lymph vessels. This process helps form tumors in distant tissues. A key step in metastasis is epithelial-to-mesenchymal transition, or EMT. EMT is a normal developmental process seen in wound healing and embryogenesis, but it also appears in cancer metastasis. It is triggered by transforming growth factor-beta (TGF-β) or receptor...

cancer-critical genes i: proto-oncogenes

Oncogenes and Cell Growth Control

Genes usually make proteins that help healthy cells work properly. When mutations change how these genes are expressed, the cell’s traits can change too. If critical genes that control the cell cycle and growth signals are disrupted, cell cycle progress can go off track and cells may divide without control. Over time, these cells can form tumors. Cancer-critical genes are the genes that drive this process. They fall into two main groups: proto-oncogenes and tumor suppressor genes.

mechanisms of retrovirus-induced cancers

How Retroviruses Trigger Cancer

Retroviruses can trigger cancer by changing how host cells grow and divide. These RNA viruses have been shown to cause cancers in species such as chickens, mice, cats, and monkeys. After infection, the viral RNA genome is reverse-transcribed into DNA. It first becomes single-stranded DNA and then double-stranded DNA. This double-stranded form, called proviral DNA, integrates into the host genome. The host cell then transcribes the proviral DNA along with its own chromosomal DNA. This process...

the ras gene

Ras Proteins: Cellular Switches in Cancer

Ras proteins are small GTPase signaling proteins that help control cell proliferation, differentiation, and cell survival. In humans, the Ras gene family has three main members: HRas, NRas, and KRas. These genes produce four closely related proteins: HRas, NRas, KRas4A, and KRas4B. Ras proteins work like molecular switches. They cycle between an active GTP-bound form and an inactive GDP-bound form. Guanine nucleotide exchange factors, or GEFs, help exchange GDP for GTP and turn Ras on.

loss of tumor suppressor gene functions

Tumor Suppressor Genes and Cancer Risk

Tumor suppressor genes help protect cells from becoming cancerous. They can slow cell division, repair DNA mistakes, or trigger apoptosis, which is programmed cell death, when damage cannot be fixed. These jobs help stop damaged cells from multiplying. When a tumor suppressor gene mutates or is lost, cells may begin to grow out of control. A single working copy is usually enough for the cell to keep normal control of the cell cycle. Cancer develops when both copies are inactivated or lost. <br...

mtor signaling and cancer progression

How mTOR Drives Cell Growth in Cancer

mTOR signaling helps control cell growth by balancing building processes and breakdown processes. mTOR stands for mammalian target of rapamycin. It was discovered in 1994 because it binds directly to rapamycin. Its name also comes from a yeast protein called TOR. In mammalian cells, the mTOR protein complex responds to environmental cues such as nutrients and growth factors. It supports anabolic processes, which are the cell’s building steps. These include the synthesis of proteins, lipids,...

cancer stem cells and tumor maintenance

How Cancer Stem Cells Drive Relapse

Cancer stem cells help tumors survive treatment and return after therapy. These residual cells can remain after early diagnosis and treatment, and they often lead to tumor recurrence. They are important because they can self-renew and also produce more than one cell type, which makes them hard to eliminate. Cancer stem cells are thought to come from normal stem cells or progenitor cells in a tissue. Normal stem cells usually stay quiet, or quiescent, until a signal tells them to divide or...

mouse models of cancer study

Mouse Cancer Models in Drug Testing

Mouse cancer models help scientists study how tumors start, grow, and respond to treatment. Mice are widely used because they are similar to humans in many biological and body functions. They are also easy to keep and breed in the laboratory, so many inbred strains are available for research. Cancer research has made major use of genetically modified mice. Transgenic mice carry an added gene, while knockout and knock-in mice have genes deleted or changed with genetic engineering. If a gene...

cancer prevention

Diet and Exercise in Cancer Risk

Diet and exercise can play a major role in cancer risk. Studies show that about 50% of cancer cases may be prevented through a healthy lifestyle, regular exercise, and a modest cancer prevention diet. Populations that eat more fruits and vegetables tend to have lower cancer rates. In contrast, diets high in animal fat, red meat, junk food, or calories are linked with a higher risk of cancer. Plant compounds called phytochemicals may also help protect against cancer. These natural chemicals...

cancer therapies

Combining Cancer Treatments

Cancer treatments often combine surgery, radiation therapy, and chemotherapy. These methods are used to treat cancer patients, but they can also damage normal cells. Cancer cells can also change quickly and become resistant to chemical agents or radiation therapy. Not every cancer responds to the same therapy. Some cancer cells respond to one treatment, while others respond to another because they carry different mutations. The best treatment depends on the type of cancer and how far it has...

targeted cancer therapies

How Targeted Cancer Drugs Work

Targeted cancer drugs are designed to act on specific molecular features that help cancer cells grow and spread. They are also called molecular targeted therapies. These treatments depend on a detailed understanding of the differences between cancer cells and normal cells, so the drug can focus on the cancer cell’s driving signals without harming healthy cells as much. One major group is angiogenesis inhibitors. Angiogenesis means the formation of new blood vessels, which tumors use to get...

treatment resistant cancers

How Cancer Cells Resist Treatment

Cancer cells can resist treatment by changing how they respond to anticancer drugs. This resistance makes cancer harder to treat. It also helps explain why cancer remains a major health problem. Cancer is the second leading cause of death in the United States. Cancer cells are genetically unstable, so they can mutate quickly. They can also change their microenvironment, which helps them avoid immune surveillance. In many tumors, resistance develops when cells alter drug transport or drug...

combination therapies and personalized medicine

combination-therapies-and-personalized-medicine

Cancer Treatment Pairings and DNA-Guided Care

Combination therapy for cancer uses two or more treatments together to improve patient outcomes. This approach can extend life span and help protect vital organs and tissue from the damage that may come from using one treatment too much. It also attacks more than one cancer-causing pathway, which can lower the chance of treatment resistance. A clear example is the pair of acetazolamide and sulforaphane. Large tumors often have a low-oxygen, acidic center, and cancer cells respond by making...

cancer-critical genes ii: tumor suppressor genes

cancer-critical-genes-ii-tumor-suppressor-genes

How Tumor Suppressor Genes Prevent Cancer

Tumor suppressor genes help keep cell growth under control. They can slow cell division, repair DNA errors, or trigger apoptosis, which is programmed cell death. These jobs protect healthy cells and help maintain normal cell cycle progression. When a tumor suppressor gene is disrupted, cells can lose this control. Loss-of-function mutations in these genes can let damaged cells keep dividing. Over time, that unchecked growth can contribute to tumor formation and cancer. Most tumor suppressor...

the retinoblastoma gene

Retinoblastoma Gene and Childhood Eye Tumors

The retinoblastoma gene, or Rb, is a tumor suppressor gene linked to a rare eye cancer in children. Tumor suppressor genes are normal genes that help slow cell division, fix DNA mistakes, or trigger apoptosis, which is programmed cell death when damage cannot be repaired. These genes help protect the body from damaged cells growing out of control. Rb was the first tumor suppressor gene ever identified. It was discovered through study of retinoblastoma, one of the most common malignant tumors...

rous sarcoma virus (rsv) and cancer

How RSV Uses Src to Drive Tumor Growth

Rous sarcoma virus, or RSV, is a retrovirus that can trigger tumor growth in chickens. F. Peyton Rous first discovered it in 1911 as a filterable transmissible agent. His work showed that some cancers can be caused by infectious agents. He later received the Nobel Prize in 1966 for this discovery, which also helped lead to the finding of other cancer-causing viruses in animals and humans. RSV carries two copies of a plus-strand RNA genome. Its genome has four main open reading frames, or ORFs:...

key terms and concepts

Learn how cancer cells gain growth advantages, use telomerase to avoid aging, and adapt to low-oxygen tumor conditions in this high school science page.

How Cancer Cells Survive and Spread | JoVE K12

molecular biology

JoVE Core Molecular Biology showcases the molecular processes of the cell through clear and concise animated video lessons. Additionally, in scientist-in-action videos, these concepts' application is demonstrated through real experiments in modern laboratories.

Texas Essential Knowledge and Skills

Biology

BIO.6

BIO.6.C

Nucleic Acids and Nucleotides

Nucleic acids are the most important macromolecules for the continuity of life. They carry the cell&#39;s genetic blueprint and have instructions for its ...

Nucleic Acid Structure

The pentose sugar in DNA is deoxyribose, while in RNA the pentose sugar is ribose. The difference between the sugars is the presence of the hydroxyl group ...

DNA Base Pairing

Erwin Chargaff&#x2019;s rules on DNA equivalence paved the way for the discovery of base pairing in DNA. Chargaff&#x2019;s rules state that in a ...

From DNA to Protein

The flow of genetic information in cells from DNA to mRNA to protein is described by the central dogma, which states that genes specify the sequence of ...

The DNA Helix

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most viruses. DNA ...

The Central Dogma

The central dogma explains the flow of genetic information from DNA nucleotides to the amino acid sequence of proteins.
RNA is the Missing Link Between ...

Genomic DNA in Prokaryotes

The genome of most prokaryotic organisms consists of double-stranded DNA organized into one circular chromosome in a region of cytoplasm called the ...

Genomic DNA in Eukaryotes

Eukaryotes have large genomes compared to prokaryotes. To fit their genomes into a cell, eukaryotic DNA is packaged extraordinarily tightly inside the ...

Overview

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most ...

DNA Packaging

Overview

Eukaryotes have large genomes compared to prokaryotes. In order to fit their genomes into a cell, eukaryotes must pack their DNA tightly inside ...

RNA Structure

Overview
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form ...

RNA Stability

Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations ...

pre-mRNA Processing

In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or ...

Types of RNA

Overview
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs ...

DNA as a Genetic Template

What is Gene Expression?

A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is comprised&#160; of nucleotides and proteins are ...

Transcription

Transcription is the synthesis of RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. ...

Translation

Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes ...

Ribosomes

Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that ...

tRNA Activation

Initiation of Translation

Termination of Translation

What are Cells?

Cell Diversity

The concept of a cell started with microscopic observations of dead cork tissue by Robert Hooke in 1665. Hooke coined the term &#34;cell&#34; based on the ...

Cells of the Epidermis

The epidermis is made of four or five layers of epithelial cells, depending on its location in the body. From deep to superficial, these layers are the ...

Bone Cells and Tissue

Bones contain a relatively small number of cells entrenched in a matrix of organic and inorganic components. Although bone cells compose only a small ...

Gross Anatomy of Skeletal Muscles

The connective tissues play a significant role in arranging the muscle fibers into a hierarchical structure that forms a complete muscle. Consider a ...

Structure of Cardiac Muscles

Cardiac muscle, or myocardium, is a specialized type of muscle found exclusively in the heart. Its unique structural and functional characteristics enable ...

structure-and-organization-of-smooth-muscles

Structure and Organization of Smooth Muscles

In the human body, smooth muscle tissue is found lining the visceral and tubular organs such as the liver, lungs, blood vessels, and respiratory tract.
...

Chromosome Replication

Before a cell can divide, it must accurately replicate all of its chromosomes, including the DNA and its associated histone and non-histone ...

Neurons: The Cell Body and the Dendrites

A typical nerve cell comprises three main components: the cell body, dendrites, and the axon. The cell body, also known as the soma or perikaryon, serves ...

Lampbrush Chromosomes

In 1882, Flemming observed lampbrush chromosomes (LBC) in salamander eggs. Later in 1892, R&#252;ckert observed LBCs in shark egg cells and coined the ...

Neurons: The Axon

The axon is a long, thin extended portion of the neuron that carries impulses from its cell body toward the effector cell.
Axoplasm, the axon&#39;s ...

Polytene Chromosomes

Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in ...

Nervous Tissue: Neuron Types

Neurons, the fundamental units of the nervous system, can be classified based on both their structural and functional characteristics.
Structurally, ...

Euchromatin

The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions ...

Nervous Tissue: Glial Cells

Glial cells or neuroglia are non-neuronal cells in the nervous system that outnumber neurons. These include astrocytes, oligodendrocytes, microglia, and ...

Heterochromatin

Lymphoid Cells and Tissues

Lymphoid cells and lymphoid tissues are the two major components of lymphoid organs.
Lymphoid cells consist of immune system cells such as B and T ...

chromatin-position-affects-gene-expression

Chromatin Position Affects Gene Expression

Chromatin is the massive complex of DNA and proteins packaged inside the nucleus. The complexity of chromatin folding and how it is packaged inside the ...

Two structural features of the DNA molecule provide a basis for the mechanisms of heredity: the four nucleotide bases and its double-stranded nature. The ...

Organization of Genes

Chromosome Structure

A functional eukaryotic chromosome must contain three elements: a centromere, telomeres, and numerous origins of replication.
The centromere is a DNA ...

Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells. Emphasis is on the conceptual understanding that DNA sequences determine the amino acid sequence and thus protein structure. Students can produce scientific writing, or presentations, and/or physical models that communicate constructed explanations.

HS-LS1-1

Characteristics of Life

Biology is a natural science that studies life and living organisms, including their structure, function, development, interactions, evolution, ...

https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/10647.jpg

Levels of Organization

Biological organization is the classification of biological structures, ranging from atoms at the bottom of the hierarchy to the Earth&#x27;s biosphere. ...

The Scientific Method

The scientific method is a detailed, empirical problem-solving process used by biologists and other scientists. This iterative approach involves ...

Taxonomy

Taxonomy is the science of defining and naming groups of biological organisms based on shared characteristics. It uses a hierarchy of increasingly ...

Phylogeny

Phylogeny is concerned with the evolutionary diversification of organisms or groups of organisms. A group of organisms with a name is called a taxon ...

Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. Emphasis is on functions at the organism system level such as nutrient uptake, water delivery, or organism movement in response to neural stimuli. An example of an interacting system could be an artery depending on the proper function of elastic tissue and smooth muscle to regulate and deliver the proper amount of blood within the circulatory system.

HS-LS1-2

Overview of Metabolism

Living cells constantly carry out various chemical reactions which are necessary for their proper functioning. These reactions are interlinked to one ...

Regulation of Metabolism

Cellular needs and conditions vary from cell to cell and change within individual cells over time. For example, the required enzymes and energetic demands ...

Positive and Negative Feedback Loops

Animal organs and organ systems constantly adjust to internal and external changes through a process called homeostasis (&#34;steady state&#34;). Examples ...

Functions of Life

Human life is characterized by a variety of functions that are essential for survival and well-being. These functions include metabolism, movement, ...

Requirements for Human Life

The Earth and its atmosphere have provided humans with air, water, and food, but these are not the only requirements for survival. Humans also require a ...

What is Homeostasis?

Maintaining homeostasis requires that the body continuously maintain its internal conditions. Each physiological condition has a particular set point, ...

Negative and Positive Feedback

Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis in living organisms. Examples of investigations could include heart rate responses to exercise, stomate responses to moisture and temperature, root development in response to water levels, or cell response to hypertonic and hypotonic environments.

HS-LS1-3

How Cancer Cells Survive and Spread

Description

Transcript

Tags

More videos by Standards