Apoptosis and Necrosis

Question 1

Two types of Neoplasms

Answer 1

• BENIGN- slow growth, localized,encapsulated,resembles cell of origin, few mitosis, normal or slight increase in ratio of nucleus to cytoplasm. Cells are uniform throughout the tumor,resembles cells of origin (well differentiated).
• MALIGNANT-rapid growth/proliferation,may spread. Abnormal growth tissue,cancer cell unregulated,cells and nuclei vary in shape and size, high nuclear to cytoplasmic ration, many mitosis, NOT ENCAPSULATED.

Question 2

Carcinoma

Answer 2

Malignant tumor growing from Epithelial tissue cancer

-glands

Question 3

Sarcoma

Answer 3

Malignant tumor growing from Connective tissue cancer

• bones
• blood
• cartilage
• fat
• muscle
• tendons

Question 4

Metastasis

Answer 4

Distant spread of the tumor cells into other tissues of the body.
MODES
-Vascular-veins
-Lymphatic-lymphatic vessels
-Transcoelomic-across coelomic spaces
Ex. Peritoneal and pleural cavities

Question 5

Tumor formation (two theories)

Answer 5

• Clonal evolution-develops through repeated rounds of mutation and proliferation
• cells acquire selective growth advantage over neighbor cells
• Stem cell evolution
• Tumors contain cancer stem cells
• Indefinite proliferative potential
• Linked initially to Leukemia’s

Question 6

Two major mechanisms of Cell death

Answer 6

• NECROSIS
• Ischemia
• toxins
• infections
• trauma
• APOPTOSIS
• Regulated cell death
• Occurs throughout adulthood and development
• Physiological (development, tissue homeostasis) and some pathological conditions such as DNA damage, misfolded proteins, some viral infections

Question 7

Necrosis (PACCLCSI)

Answer 7

• Pathological
• Acute cell injury
• Cell swelling
• Cell unable to maintain homeostasis
• Loss of tissue membrane integrity ( damage to plasma membrane)-Random DNA degradation
• Cell contents released
• Surrounding tissue damage
• Inflammation

Question 8

APOPTOSIS

Answer 8

• Physiological
• Genetic
• Programmed cell death
• Cell shrinking
• Maintains plasma membrane integrity
• PLASMA MEMBRANE BLEBBING
• DNA aggregation-Aggregation of chromatin
• Fragmentation of oligonucleosomal DNA/Nucleus
• Capsase cascade activation
• No surrounding tissue damage
• No inflammation

Question 9

ASSESMENT OF NECROSIS

Answer 9

MORPHOLOGICAL

• Propidium Iodide (PI) staining
• PI positive-leaky/discontinuous plasma membrane-necrosis
• H&E staining
• increased eosinophilia
• variable nuclei staining
• TEM
• Discontinuous plasma and organelle membranes

BIOCHEMICAL
-Random DNA degradation- increased levels of LDH-Lactate dehydrogenase

Question 10

CYTOKINES MACROPHAGE RELEASES TO INHIBIT INFLAMMATION

Answer 10

** ILB-10

** TGF-BETA

Question 11

CYTOCHROME C

Answer 11

Released from the mitochondria for apoptosis

Question 12

WEBBING OF HUMAN TOES

Answer 12

Interruption of Apoptosis

Question 13

Mechanisms of Apoptosis

-TWO PATHWAYS

Answer 13

• Intrinsic
• Death signal received
• Pro-apoptotic proteins unregulated
• Release of cytochrome c from mitochondria
• Apoptosome formation (Apache-1,cytochrome c, procaspace 9)
• Caspase cascade-activation of initiator Caspace 9 and effector Caspace 3
• Extrinsic
• Binding of ligand to death receptor
• Fas ligand
• Recruitment of death adaptor proteins
• FADD
• TRADD
• Formation of death inducing signaling complex (DISC)
• Capsase cascade:
• Activation of initiator Capsase 8
• Activation of effector or “executioner” caspases ex. Caspase 3

Question 14

CASPACE FAMILY

Answer 14

Family of protease enzymes

• Cysteine dependent, aspartame-directed protease
• synthesized as inactive precursors-procaspaces
• activated by proteolytic cleavage
• target cytoplasmic and nuclear proteins and Caspace-active DNAse

Question 15

CASPASE 1

Answer 15

Cytokines maturation

Question 16

CYTOKINES 2,8,9,10

Answer 16

INITIATOR CASPACES

Question 17

CASPASES 3,6,7

Answer 17

Effector/Executioner Caspases

Question 18

CASPASES 4,5

Answer 18

INFLAMMATION

Question 19

CASPASE 14

Answer 19

Skin development

Question 20

Bcl-2 protein family

*Intracellular regulators of apoptosis

Two classes:

Answer 20

Pro-apoptotic/pro-death

• [Bak
• [Bax
• *both of the above : permeabilization/ entering of mitochondrial outer membrane
• Bid-links extrinsic and intrinsic pathways

Anti-apoptotic/anti-death

• Bcl-2
• Bcl-xL

Question 21

ASSESSMENT OF APOPTOSIS

***CAD E T

Answer 21

C- Capsase activity

A- Annexin 5- this protein binds to phosphatidylserine when exposed on the outer leaflet of plasma membrane

D- DNA Laddering: DNAse cleaves internucleocomal DNA, 180-200bp fragments

T-TUNEL-this assay detects DNA fragmentation
Terminal Uridine deoxynucleotidyl transferase nick end labeling. Tagged or labeled deoxynucleotides to 3’ DNA ends