Stem CellsCloningCancer

Stem Cell Research

What Are Stem Cells?• Stem Cells are unspecialized cells, this

means that they do not have a specific function in the body yet.

• They are cells that are capable of dividing and renewing themselves for long periods.

• Stem Cells can become specialized cells. This means that these cells can be given a specific function for the body.

Human embryonic stem cell colonies in different stages of

development. An Embryonic stem cell

A Clump

of Stem Cells

There are two basic types of Stem Cells:

Embryonic & Adult

Embryonic Stem Cells• Embryonic stem cells come

from embryos. • Five days after fertilization,

the human embryo becomes a hollow sphere of about 100 cells. The embryonic stem cells are in the center of the sphere.

• These stem cells have the ability to transform themselves into any other type of cell in the body.

How Embryonic Stem Cells are obtained and Grown

Adult Stem Cells• Adult Stem cells are not completely specialized

cells found among functional cells in a tissue or organ like the brain, skin and liver.

• The primary role of adult stem cells are to maintain and repair the tissue that they are found.

• They can only become cells or tissues for the area of the body where they are found.

• In adults there are a very small amount of stem cells in each tissue.

Differences Between Embryonic and Adult Stem Cells

Topic Embryonic AdultPotential in

the bodyThey can become almost any

cell, tissue or organ in the body .Limitations to what they can transform to and they don’t

transform as quickly.

Practicality They can be grown in culture in an unlimited quantity.

They are difficult to grow and slow to produce in large quantity.

Compatibility Often rejected due to incompatibility between donor

and recipient.

Rarely rejected by patients (because the donor is the recipient)

Cancer Connection

They are more likely to become cancerous.

Less likely to become cancerous.

Controversy Creates controversy because a viable embryo must be

destroyed to obtain them.

Aren’t as controversial because adults can choose to donate them, as they do with blood or organs.

Why Are They Important?• Potential is enormous

because they can help us to understand more about the development of the human body.

• They have the ability to restore any type of cell and could help cure nearly any disease, condition or injury.

• They hold the promise of the complete regeneration of the human body.

What could stem cells be used to treat someday?

• Cancer• Alzheimer disease• Diabetes• Spinal cord injuries• Hemophilia• Muscular dystrophies

1

Cloning

DEFINITIONS• CLONE• 1. A cell, group of cells, or organism that is

descended from and genetically identical to a single ancestor.

• 2. An organism descended asexually from a single ancestor.

• CLONING• 1. To make multiple identical copies of a DNA

sequence.• 2. To create or propagate an organism from a

clone cell.• 3. To produce a copy of self.

USEFULNESS

• Cloning can be used to test for genetic diseases

• Regenerate nerves or spinal cord tissue• Help in plastic surgery • Clone organs for transplantation• Grow skin grafts for burn victims• Manufacture bone, fat, and cartilage

Animal Cloning

Dolly and her surrogate mother.

The Biotechnology of Reproductive Cloning

Even under the best of circumstances, the

current technology of cloning is very

inefficient. Many of the cloned animals die.

Cloning provides the most direct

demonstration that all cells of an individual

share a common genetic blueprint.

Why Clone Animals?

To answer questions of basic biology

Five genetically identical cloned pigs.

For herd improvement. To satisfy our desires (e.g. pet cloning).

For pharmaceutical production.

Recombinant DNA, Gene Cloning, and Pharmaceutical Production

DNA can be cut at specific sequences using restriction enzymes.

This creates DNA fragments useful for gene cloning.

These are mature and widely utilized biotechnologies.

Bacteria and their plasmids are used for genetic engineering.

Plasmids are small circles of DNA found in bacteria.

Pieces of foreign DNA can be added within a plasmid to create a recombinant plasmid.

The result is a bacterial cell that can produce the protein that the geneticist wants, along with all of the proteins that the bacterium needs to survive.

MORAL/ETHICAL ISSUE

What are the implications of cloning?How will cloning affect the medical field?What will be the effect on the gene pool?Is there potential for abuse?How should it be regulated?Would you consider cloning yourself?

Cancer – Mitosis Gone Wild

CancerDefinition / Causes

– Cancer is the uncontrolled growth of cells– Changes in a cells’ DNA can lead to unrestrained

cell reproduction– Cells are produce a growth factor and never stops

dividing OR– Cells do not produce a suppressor protein and it

never stops dividing

Cancer

Tumors - 2 types

1. Benign - slow growing, noninvasive, no metastasis

2. Malignant - rapid growth, invasive, metastatic

Genetic Connections to Cancer

Some forms of cancers have been shown to be associated with a particular gene sequence.People who have this gene are more likely to develop a particular form of cancer.Using Gene Therapy may be a method of protecting people against these cancer genes.

Genetic Connections to Cancer

One day, perhaps in the distant future, stem cells may help repair diseased tissues. But there is a far more pressing reason to study them: stem cells are the source of at least some, and perhaps all, cancers.At the heart of every tumor, some researchers believe, lie a handful of aberrant stem cells that maintain the malignant tissue.The idea, if right, could explain why tumors often regenerate even after being almost destroyed by anticancer drugs. It also points to a different strategy for developing anticancer drugs, suggesting they should be selected for lethality to cancer stem cells and not, as at present, for their ability to kill just any cells and shrink tumors.