L8: Cancer & Physical activity

Question 1

What are the two types of mutations that can occur and lead to cancer?

Answer 1

1. Tumour suppressing genes

2. Oncogenes

Question 2

What are tumour suppressing genes?

Answer 2

Genes responsible for slowing down cell growth, cell devision and Repair/apoptosis. Mutations causes rapid growth and proliferation.

Question 3

What are oncogenes?

Answer 3

Genes that provide mitogenic signals for cell growth which bypass DNA repair mechanisms. Proto-oncogenes are healthy versions.

Question 4

What are the TWO types of methods of acquiring mutations?

Answer 4

1. Inheritance via germ-line

2. Acquired via carcinogens.

Question 5

What is p53 gene?

Answer 5

Responsible for regulating cell cycle and acts as a tumour suppressor. Mutations that cause p53 dysfunctions causes uncontrolled cell growth and proliferation.

Question 6

What do Natural killer T-cells do?

Answer 6

Produced in the thymus, NK cells bind to MHC-1 receptors on cell membranes of healthy cells or alternatively Ligands of virus infected or cancerous cells which initiates pathways to destroy cells.

Question 7

What are the TWO pathways for NK cells to destroy cells?

Answer 7

1. Granzyme secretion

2. Specific immune response via cytokines.

Question 8

What percentage of cancer-related mortalities are from secondary metastasis

Answer 8

90%

Question 9

What cells are tumours composed of?

Answer 9

Tumour cells, cancer stem cells, healthy cells, stromal cells

Question 10

Explain why NK cell recruitment and activity increases in response to exercise?

Answer 10

Exercise increases blood pressure due to increases muscle resistance. This produces shear stress on the blood vessels which triggers the sympathetic nervous system to releases epinephrine and norepinephrine. NK cells express more B-adrenergic receptors compared to other immune cells, thus are highly responsive.

Question 11

What are the different methods in which exercise can prevent cancer and improve response to cancer?

Answer 11

1. Changes in hormones and signalling
2. Drug improvement
3. NK cell activity and concentrations

Question 12

What is the Warburg effect?

Answer 12

Cancer cells favour lactate production pathway from glycolysis rather than pyruvate. This increases susceptibility of exercise-induced stress leading to the over expression of GLUT-1 receptors increases glucose consumption of cell.

Question 13

What are the different changes in hormones induced by exercise which effects cancer and why?

Answer 13

1. Oestrogen levels decrease In response to reduce adipose levels. Identified low levels of Oestrogen related to reduced breast cancer risk.
2. Increase insulin sensitivity
3. Transition from pro-inflammatory molecules to anti-inflammatory molecules reducing cell dysfunction.
4. Increase T-cell, NK cells and neutrophil production and activity.

Question 14

How does exercise improve cancer drug treatment?

Answer 14

Cancer cells usually create an hypoxic environment due to their enlarge irregular shapes. Angiogenesis occurs in an attempt to improve blood flow to the cells. Exercise increase vascular structure and angiogenesis response increasing blood flow and subsequently nutrients and oxygen to the cancer cells. This also means that treatments such as chemotherapy reach the cancer cells more effectively. Exercise also improves immune function especially due to increased NK cells and activity thanks to their high levels of adrenergic receptors. Drug response and delivery thus improves increasing the chances of eliminating all cancer stem cells - the largest contributor to secondary metastasis.