11. Cancer cell death

Question 1

Define apoptosis

Answer 1

Programmed cell death occurring as a normal part of organisms growth and development - this is active

Question 2

Define necrosis

Answer 2

The death of tissue due to injury, disease or ischemia - this is passive

Question 3

What happens to the nucleus during apoptosis?

Answer 3

The nucleus and genetic material condenses

Question 4

What happens to the mitochondria during apoptosis?

Answer 4

The mitochondria condense

Question 5

What are the morphological features of apoptotic cells?

Answer 5

Cellular and nuclear condensation
Nuclear fragmentation
Nuclear and mitochondrial condensation
Cellular fragmentation

Question 6

What can apoptosis be induced by?

Answer 6

Heat shock 
Viral infection 
Toxins 
Oncagenes 
Free radicals 
Nutrient deprivation 
Chemotherapeutic drugs
Radiation

Question 7

What is meant by ‘immunogenic cell death (ICD)’?

Answer 7

A cell death modality that does stimulate an immune response against dead-cell antigens - in particular when they derive from cancer cells

Question 8

When is ATP released during apoptosis?

Answer 8

During the blebbing stage

Question 9

What is the main organelle responsible for the regulation of apoptosis?

Answer 9

Mitochondrion

Question 10

What are lymphocytes?

Answer 10

WBC in the blood and the lymphoid organs
B cells
T cells
NK cells

Question 11

What are phagocytes?

Answer 11

WBCs that can swallow and digest microscopic organisms via phagocytosis

Question 12

What are monocytes?

What do monocytes differentiate into?

Answer 12

Circulate in the blood and differentiate into macrophages and dendritic cells

Question 13

What are dendritic cells?

Answer 13

Specialised antigen presenting cells to the immune system

Question 14

Where are immune cells produced?

Answer 14

Precursors in the bone marrow

Question 15

Where are immune cells derived from?

Answer 15

Haematopoetic stem cells

Question 16

What are the functions of T-cells?

Answer 16

Killing (cytotoxic) , activation (helper) and regulation (regulatory t cells)

Question 17

How can cancer cells escape immunosurveillance?

Answer 17

Altering their characteristics e.g. downregulation of MHC I
Suppressing the immune response e.g. immunosuppressive cytokine
Outpacing the immune response - proliferate faster than the immune system can kill them

Question 18

What cells do NK cells work on?

Answer 18

NK cells kill cells coated with an antibody

Question 19

What are PAMPs recognised by?

Answer 19

These are recognised by toll-like receptors in the innate system on dendritic cells and macrophages

Question 20

What are PAMPs recognised by?

Answer 20

These are recognised by toll-like receptors in the innate system on dendritic cells and macrophages

Question 21

What are the cells of the innate system?

Answer 21

Granulocytes: neutrophil, eosinophil, basophil, monocyte

Question 22

What are the cells of the adaptive immune system?

Answer 22

Lymphocytes - B cells (humoral) and T-cells (cellular)

Question 23

What are the cells that bridge the gap between the innate and the adaptive immune system?

Answer 23

Dendritic cells

Question 24

How does the immune system kill cancer cells?

Answer 24

T cells - CD8 and CD4+ 
B cells - antibodies
Cytokine release 
Dendritic cells
NK cells - activated for direct killing of the tumour cells 
Macrophages - antigen presenting

Question 25

What cytokines are involved in cancer cell death?

Answer 25

IFN-alpha
IL-2
IL-12
GM-CSF

Question 26

How many times can a normal human cell population divide?

Why?

Answer 26

52

The telomeres of the cell will get shorter and shorter each time the cell divides until they shorten to a critical length