Cancer Cell Biology Exam 1 (Pt. 1)

The Nature of Cancer and the Hallmarks of Cancer

What is cancer?

An altered form of a normal cell that exhibits roughly six hallmarks. It is monoclonal in nature.

Carcinogenesis

The process in which cancer develops.

Carcinomas

Cancer arising from epithelial cells.

Squamous cell carcinomas

Tumors that arise from epithelial cells that form protective layers.

Adenocarcinomas

Tumors that arise from specialized cells within the epithelia that secrete products into the ducts or cavities that they line. This can occur in the lungs, uterus, and the cervix.

Sarcomas

Tumors derived from mesenchymal tissues. These include connective tissue, fibroblasts, and adipocytes.

Hematopoietic tissue

Leukemias and lymphomas

Tumors derived from blood forming cells and lymphocytes.

Neuroectodermal tumors

Found on various components of the central and peripheral nervous system.

Retinoblastoma

Derived from the stem cells of the retina.

Glioblastoma

Derived from the stem cells of the glia.

Neuroblastoma

Derived from neuron stem cells.

Anaplastic

Cancer cells that appear normal but present in large numbers (hyperplastic growths). They divide rapidly.

Dysplasia

The presence of abdominal cells within a tissue or organ.

Adenoma, polyps, papillomas, warts

Found in the epithelium and can be identified by the naked eye. They grow to a certain size and then stop.

Mutagenesis

A permanent alteration of the genetic material (DNA) of the cell and is heritable by the daughter cell.

Germinal mutation

Damage to the DNA of the ova or sperm and can be passed to future generations.

Somatic mutation

Damage to DNA in non-germ cells and cannot be passed on to future generations. But it is passed on to daughter cells.

Mutagens

Chemical and physical agents capable of producing mutations (radiation, chemotherapeutic agents, many carcinogens, etc.)

How does a normal cell become cancerous?

Damage done to DNA.

Which sex gets colon cancer more?

Men.

At what age does colon cancer rates dramatically increase?

50.

Cancer susceptibility factors:

Age, environment, high body fat, and genetic makeup.

What percent of cancers are environmentally induced?

35-80%

How many distinct types of cancer are there?

More than 100.

Doctor that demonstrated that some aspects of cancer could be explained by altered forms of normal cellular genes:

Dr. Robert Weinberg.

How many hallmarks of cancer are there?

Six.

What are the six hallmarks of cancer?

Self-sufficiency in growth signals, insensitivity to anti-growth signals, tissue invasion and metastasis, limitless replicative potential, sustained angiogenesis, and evading apoptosis.

If a component of the circuit is altered, then the entire cellular circuit is_____.

altered

T/F: Cancer cells require growth signals to continue cell division.

False.

T/F: Cancer cells can make their own growth signals.

True.

T/F: NORMAL cells require mitogenic growth signals before they can shift to an active proliferative state.

True.

Alterations in extracellular growth signals, such as…

PDGF, EGF.

Alterations of transcellular transducers, such as…

RAS

“Alterations of intracellular circuits that translate those signals into actions",” is an example of?

Self-sufficiency in growth signals

Cancer cells acquire the ability to synthesize growth factors to which they are responsive - creating a positive feedback loop called _____.

Autocrine Signalling

Anti-growth signals

Antiproliferative signals that operate to maintain tissue homeostasis.

Immobilized inhibitors are found…?

embedded in the extracellular matrix and on the surface of nearby cells.

Mitogens are an example of…?

growth signals

TGF-Beta is an example of an…?

anti-growth signal.

T/F: Growth signals take precedence over antigrowth signals.

False.

Contact inhibition

Cell-to-cell contacts formed by dense populations of normal cells propagated in culture operate to suppress further proliferation.

Merlin

A membrane-cytoskeleton linker protein that acts as a tumor supressor

T/F: The NF2 gene encodes Merlin

True

Which tumor suppressor regulates contact inhibition?

Merlin

How does Merlin regulate contact inhibition?

Localizes the cell cortex and restrains mitogenic receptors.

Restraining mitogenic receptors inhibits…?

Epidermal Growth Factor Receptor (EGFR)

Apoptosis

Programmed cell death.

Mitochondria

Secretes pro-apoptotic factors and where many apoptotic signals converge

p53

Transcription factor- upregulate pro-apoptotic genes

Caspases

Family of intracellular proteases that destroys cellular structures (including the cell).

PI3K kinase-AKT pathways

Transmits anti-apoptotic (pro-survival) signals

IFG1/2 and IL-3 are examples of…?

external survival factors

Normal human fetal cells will replicate between ____ times before it stops.

40 and 60

Senescene phase

When cells permanently stop dividing but remain metabolically active.

This Doctor discovered that cells divide a finite amount of times.

Dr. Hayflick