Name: proto-oncogenes and cell growth control
Uploaded: 2023-04-30T18:28:51.000Z
Duration: 1 min 33 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Life Science

SC.912.L.16

SC.912.L.16.8

Cancer-Critical Genes I: Proto-oncogenes

Cancer-critical genes are a group of genes that, upon mutation or alteration, contribute to the development of cancer.&#160;
These genes can be categorized into two major classes based on how the mutation affects gene activity - proto-oncogenes and tumor-suppressor genes.
Under normal conditions, proto-oncogenes encode for proteins that act as signals for cell division. A gain-of-function mutation in the proto-oncogenes converts them into an overactive form called oncogenes.
The activation of oncogenes leads to overexpression of the cell-growth proteins resulting in uncontrolled cell proliferation and, hence, the formation of a tumor.
Gain-of-function mutations in proto-oncogenes are usually dominant, and even a single mutation can transform them into an oncogene.
For example, the proto-oncogene Ras encodes for an intracellular signal-transduction protein, Ras. Upon activation, Ras switches ON the cell growth signaling cascades. Upon mutation, the Ras gene turns into an oncogene and produces a mutated protein. This mutated Ras switches ON the signaling pathways, even in the absence of any activation signals, leading to the uncontrolled growth of cells and, ultimately, tumor formation.

cancer-critical genes i: proto-oncogenes

Genes usually encode proteins necessary for the proper functioning of a healthy cell. Mutations can often cause changes to the gene expression pattern, thereby altering the phenotype.
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act as the drivers for cancer are termed cancer-critical genes and are categorized into two broad classes - proto-oncogenes and tumor suppressor genes. In their normal state, proto-oncogenes encode for proteins involved in cell cycle regulation that control cellular growth and division. But gain-of-function mutations in proto-oncogenes turn them into overactive forms called oncogenes that make the cells grow out of control, leading to cancer. In most cases,&#160; these cancer-causing mutations are acquired and not inherited. Some of the most common examples of proto-oncogenes in humans are Ras, HER2, Myc, and Cyclic D.
The major difference between proto-oncogenes and tumor suppressor genes is that proto-oncogenes lead to cancer upon over-activation, while tumor suppressor genes cause cancer when they are inactivated

Genes usually encode proteins necessary for the proper functioning of a healthy cell. Mutations can often cause changes to the gene expression pattern, ...

Education

JoVE Core

Cell Biology

Unit 1

Cancer

KEY TERMS AND CONCEPTS

proto-oncogenes and cell growth control

Proto-oncogenes are cancer-critical genes that help control normal cell growth. They play an important role in the signals that tell cells when to grow and divide. In healthy cells, these genes support regular cell behavior.

Problems can begin when a proto-oncogene changes. A changed proto-oncogene may push a cell to divide too often or at the wrong time. This shift can contribute to cancer development.

This topic focuses on proto-oncogenes as one class of cancer-related genes. It shows how genes that normally support growth can become harmful when their function changes. Understanding this change helps explain why certain cells lose normal growth control.

Proto-oncogenes and Cell Growth Control

what is cancer?

How Cancer Cells Grow and Spread

Cancer is a disease in which cells grow and divide in an uncontrolled way. In healthy tissue, cell growth is regulated so the body can stay balanced and repair itself. In cancer, that control is lost. Cancer can start when cells in a specific tissue begin to divide too often. These abnormal cells may form a mass called a tumor. Some cancers stay in one place, while others spread to other parts of the body. The term cancer covers many diseases, not just one condition. Different cancers can...

cancers originate from somatic mutations in a single cell

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

Single-Cell Mutations Can Lead to Cancer

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tumor progression

Tumor Growth and Spread

Tumor progression describes how a tumor changes over time. It includes tumor growth and, in some cases, spread to other parts of the body. These changes help explain why cancer can become more serious. As tumor cells divide, the tumor can increase in size. Some tumors stay in one place, while others become more aggressive. When a tumor spreads, cancer cells move away from the original site and start new tumors in other tissues. This process is linked to disease advancement and is a key part of...

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metastasis

How Cancer Spreads: Metastasis

Metastasis is the spread of cancer cells from the original tumor to other parts of the body. It is a key step in cancer progression and helps explain why cancer can become more difficult to treat.

Proto-oncogenes are cancer-critical genes that help control normal cell growth. They play an important role in the signals that tell cells when to grow and divide. In healthy cells, these genes support regular cell behavior. Problems can begin when a proto-oncogene changes. A changed proto-oncogene may push a cell to divide too often or at the wrong time. This shift can contribute to cancer development. This topic focuses on proto-oncogenes as one class of cancer-related genes. It shows how...

cancer-critical genes ii: tumor suppressor genes

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

Tumor Suppressor Genes in Cancer

Tumor suppressor genes help keep cell growth under control and can limit cancer development. These genes act as safeguards by slowing the cell cycle, repairing damage, or triggering cell death when cells are too abnormal to continue dividing. When tumor suppressor genes are changed or lost, cells may divide when they should not. That loss of control can contribute to tumor growth. Understanding how these genes work helps explain why some cells become cancerous while others stay normal. The...

loss of tumor suppressor gene functions

Tumor Suppressor Gene Loss in Cancer

Tumor suppressor gene loss can help cancer cells grow and survive. Tumor suppressor genes normally help control cell growth and keep cells from dividing too quickly. When these gene functions are lost, that protection is reduced. This topic also includes how tumor suppressor genes can be turned off without changing the DNA code itself. Epigenetic changes are chemical changes that affect gene activity. They can silence a tumor suppressor gene and lower its function in the cell. Understanding...

the retinoblastoma gene

Retinoblastoma Gene and Cell Cycle Control

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mechanisms of retrovirus-induced cancers

How Retroviruses Lead to Cancer

Retroviruses can lead to cancer by changing how cells grow and divide. They are RNA viruses, and their genetic material is copied into DNA after infection. That DNA can then affect the host cell in ways that promote tumor formation. A key idea is the activation of proto-oncogenes. Proto-oncogenes are normal genes that help control cell growth, but they can become oncogenes, or cancer-causing genes, when their activity is altered. Retroviruses can contribute to this change and push infected...

rous sarcoma virus (rsv) and cancer

Rous Sarcoma Virus and the Src Gene

Rous sarcoma virus (RSV) is a cancer-causing virus linked to a specific gene called src. The virus is known for its role in helping scientists understand how some cancers develop at the molecular level. The src gene is a proto-oncogene, which means it is a normal gene with the potential to become cancer-related when altered. In RSV, this gene becomes the viral v-src version. That change is important because it connects a normal cellular gene to cancer-forming activity. RSV helped reveal that...

the ras gene

Ras Gene in Cell Signaling

The Ras gene helps control cell signaling. Ras proteins act as switches that pass signals inside a cell. These signals can affect growth and other cell responses. Ras is important in many cells because it helps move information from the cell surface to the cell interior. When this signaling system is working normally, the cell can respond in an organized way. Changes in Ras can disrupt that control.

mtor signaling and cancer progression

mTOR Pathway in Cancer Growth

mTOR signaling helps control cell growth, and changes in this pathway can support cancer progression. The mTOR protein is a key part of this signaling system. It helps cells respond to signals that tell them when to grow and divide. The transcript focuses on how mTOR signaling connects to cancer. When this pathway is altered, it can affect the behavior of cancer cells. Understanding this link helps explain why mTOR is an important topic in cancer biology. mTOR signaling is studied as part of...

cancer stem cells and tumor maintenance

Cancer Stem Cells in Tumor Growth

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mouse models of cancer study

Mouse Models for Cancer Research

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cancer prevention

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cancer therapies

Cancer Treatment Options

Cancer treatment options include several ways to target cancer cells and help control the disease. Common approaches include chemotherapy, radiation therapy, surgery, and immunotherapy. Each method works in a different way, so doctors may choose one treatment or combine several. Chemotherapy uses drugs to kill fast-growing cells or stop them from dividing. Radiation therapy uses high-energy beams to damage cancer cells. Surgery removes a tumor when it can be reached safely. Immunotherapy helps...

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How Targeted Cancer Drugs Work

Targeted cancer therapies use medicines that act on specific molecules linked to cancer cell growth. These drugs are designed to interfere with signals that help cancer cells survive and divide. The goal is to affect cancer cells more directly than many traditional treatments. The transcript highlights two examples of targeted therapy. Imatinib mesylate works by blocking a protein target involved in cancer growth. Trastuzumab is another targeted drug used in cancer treatment. These therapies...

treatment resistent cancers

Why Some Cancers Resist Treatment

Some cancers resist treatment and keep growing even after therapy. This video focuses on why that happens and how resistance changes cancer care. Treatment resistance can develop when cancer cells survive drugs that should destroy them. The cells may avoid the drug’s effects, or they may keep dividing after treatment starts. This makes the cancer harder to control. Understanding treatment-resistant cancer helps explain why some therapies work at first and then lose effect. It also shows why...

combination therapies and personalized medicine

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Personalized Cancer Treatment with Drug Combinations

Personalized cancer treatment uses drug combinations to better match therapy to a patient’s tumor. It brings together combination therapies and personalized medicine to improve how doctors choose treatment. Combination therapy means using two or more drugs at the same time or in sequence. This approach can help target cancer cells in more than one way and may reduce the chance that the tumor becomes resistant to one drug. Personalized medicine uses information about the patient and the tumor...

key terms and concepts

Learn how proto-oncogenes help regulate normal cell growth and how changes in these genes can contribute to cancer in high school biology.

Proto-oncogenes and Cell Growth Control | JoVE K12

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JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

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SC.912.L.16.7

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Proto-oncogenes and Cell Growth Control

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