Apoptosis: Programmed Cell Death

1. Apoptosis

2. Review

Theword ‘‘apoptosis’’ comesfrom theancient Greek, meaning the: ‘‘falling of
petalsfrom aflower’’ or ‘‘of leavesfrom atreein autumn’’

A form of cell death in which aprogrammed sequenceof eventsleadsto the
elimination of cellswithout releasing harmful substancesinto thesurrounding area.

isamodeof cell death that occursunder normal physiological conditionsand the
cell isan activeparticipant in itsown demise

Theprogrammed suicideof cells.
Apoptosis

3. •
Apoptosis - “normal” or “programmed”
cell death
•
Necrosis - “accidental” or “ordinary” cell
death
Two mechanism of cell death

5. Importance of apoptosis
•
Normal cell turn over
•
Tissuehomeostasis
•
Induction and maintenanceof immune
tolerance
•
Development of thenervoussystem
•
Endocrine-dependent tissueatrophy
•
Elimination of activated, damaged and
abnormal cells

6. What happens when apoptosis goes wrong
•
Inappropriateapoptosisisafactor in many human
conditionsincluding neurodegenerativediseases,
ischemic damage, autoimmunedisordersand many
typesof cancer.
Too little apoptosis Too much apoptosis
Neurodegenerative
Disorder

7. Cancer
•
alargegroup of diseasescharacterized by the
uncontrolled growth and spread of abnormal
cells.

8. Traits of Cancer
•
Independent of GROW signal from other cellsoften,
oncogenes. Ex. Ras
•
IgnoresSTOPsignal defectivedamagecontrol, so problems
not corrected. Often, tumor suppressor genes. Ex. P53
•
No cell suicide(apoptosis)
If thisoccurs, treatmentswhich damagedividing cells
may not work.
•
No limit to cell divisions

9. Traits of cancer
•
Angiogenesis- formation of blood vessels
•
Metastasis- ability to moveto other tissues
benign: do not movefrom tumor site
malignant: invasivecells, can travel in
blood and lymph system

10. •
Cancer arisesfrom themutation of anormal gene.
•
Mutated genesthat causecancer arecalled
oncogenes.
•
It isthought that several mutationsneed to occur to
giveriseto cancer
•
Cellsthat areold or not functioning properly
normally self destruct and arereplaced by new cells.
•
However, cancerouscellsdo not self destruct and
continueto dividerapidly producing millionsof new
cancerouscells.

11. 8/16/16

12. Thank you!
Prepared by: Arianne Gay Ayad
8/16/16