Download cancer2 - TASIS IB Biology

THE CELL CYCLE AND CANCER
What is cancer
and how does it start?
Take 5 minutes and silently write
down your ideas.
Your Ideas
What causes cancer?
What types of cancer are there?
Cell division and cancer
Which karyotype is the bladder cancer cell?
This representative karyotype from a human
prostate cancer cell line before injection into
nude mice shows all human chromosomes
with characteristic marker chromosomes
OK…what tells a cell when to divide
(or, indeed, when NOT to divide)?
Control of the Cell cycle
• Control of the cell cycle
Cell cycle controls
Cell Cycle Control
Leland Hartwell
Isolated > 100 genes (in
yeast cells) directly
involved in control of the
cell cycle (CDC genes)
Introduced the concept of
‘Checkpoints’: where the
cell cycle stops to check if
DNA has been perfectly
duplicated, cell size is
correct, etc etc…
Cell cycle control
Sir Paul Nurse
Used another yeast cell
(Saccharomyces) to identify
the CDC2 gene (and
subsequently the equivalent
gene in humans, CDK1),
which was THE rate-limiting
step controlling onset of S,
transition from G1 to S and
from G2 to M phase of the
cell cycle
Cell Cycle Control
Tim Hunt
Used sea urchins to
identify control proteins
which were formed and
degraded throughout the
cell cycle (cyclins) and
bind with CDK molecules,
regulating CDK activity
and selecting proteins to
be phosphorylated
OK…what tells a cell when to divide
(or, indeed, when NOT to divide)?
• Let's get some help from the NOBEL
organisation...
• and how about some help from Harvard?
• Animation
Cancer & The Cell Cycle
What is the relationship
between the cell cycle and
cancer? What roles do
CDK and cyclin play in the
development of cancer?
Cell cycle regulators
• Cyclins and kinase proteins
regulate the timing of the cell
cycle in eukaryotic cells
• They are sometimes called
internal regulators – proteins
that respond to events inside
the cell
• They include growth factors
• They direct cells to speed up or
slow down the cell cycle
• They prevent excessive cell
growth and prevent tissues
from disrupting each other
What’s the link between control of the
cell cycle and cancer?
• In cancer, defective cell cycle control means that
parts of chromosomes are lost, rearranged or
unequally distributed between daughter cells
• ‘Broken’ genes for CDK and cyclins can function as
oncogenes
• Increased levels of faulty CDK and cyclins are often
identified in human cancer cells (e.g. skin, breast)
‘Faulty’ cell division: oncogenes
An oncogene is a mutated
gene that contributes to
the development of a
cancer.
In their normal state,
oncogenes areinvolved in
the regulation of cell
division
Development of a Tumor
Angiogenesis
from the Howard Hughes Medical Institute
An introduction to the biology of
cancer
• Cold Harbour website
• How does cancer compare to other
causes of death in the developed
world?
• What percentage of all deaths is
attributed to cancer?
US mortality 2010
US Mortality, 2004
Rank
No. of
deaths
Cause of Death
% of all
deaths
•
•
•
1.
Heart Diseases
2.
Cancer
•
•
•
•
•
•
•
•
•
•
•
•
9.
3.
Cerebrovascular diseases
4.
Chronic lower respiratory diseases
121,987
5.1
5.
Accidents (Unintentional injuries)
112,012
4.7
6.
Diabetes mellitus
73,138
3.1
7.
Alzheimer disease
65,965
2.8
8.
Influenza & pneumonia
•
10. Septicemia
Nephritis
652,486
553,888
42,480
27.2
23.1
150,074
59,664
6.3
2.5
1.8
33,373
1.4
Source: US Mortality Public Use Data Tape 2004, National Center for Health Statistics, Centers for Disease Control
and Prevention, 2006.
Who gets what type of cancer?
2007 Estimated US Cancer Deaths*
Lung & bronchus
31%
Men
289,550
Women
26% Lung & bronchus
270,100
Prostate
9%
15%
Breast
Colon & rectum
9%
10%
Colon & rectum
Pancreas
6%
6%
Pancreas
Leukemia
4%
6%
Ovary
Liver & intrahepatic
bile duct
4%
4%
Leukemia
3%
Esophagus
4%
Non-Hodgkin
lymphoma
Urinary bladder
3%
3%
Uterine corpus
Non-Hodgkin
lymphoma
3%
2%
Brain/ONS
2%
Kidney
3%
Liver & intrahepatic
bile duct
All other sites
24%
ONS=Other nervous system.
Source: American Cancer Society, 2007.
23%
All other sites
2007 Estimated US Cancer Deaths*
Lung & bronchus
31%
Men
289,550
Women
270,100
26%
Lung & bronchus
15%
Breast
Colon & rectum
Prostate
9%
Colon & rectum
9%
10%
Pancreas
6%
6%
Pancreas
Leukemia
4%
6%
Ovary
Liver & intrahepatic
bile duct
4%
4%
Leukemia
3%
Esophagus
4%
Non-Hodgkin
lymphoma
Urinary bladder
3%
3%
Uterine corpus
Non-Hodgkin
lymphoma
3%
2%
Brain/ONS
2%
Kidney
3%
Liver & intrahepatic
bile duct
All other sites
24%
ONS=Other nervous system.
Source: American Cancer Society, 2007.
23%
All other sites
P53: a famous oncogene
• p53 from Howard Hughes
• p53 movie
• cancer treatment using the common cold!
Key Statements from the WHO:
• Tobacco use is the major preventable cause of cancer in the world.
• Molecular genome research will reveal a tremendous amount of
information on cancer but it is not clear how easy these discoveries
will translate into actual lives saved and may well be restricted to
rare cancers
• Researchers will demonstrate that successful behavioral changes in
tobacco, alcohol and diet will prevent far more cancers than the
elimination of toxins such as industrial pollution, car exhaust and
dioxins; .
More than genes
• Tobacco, the case for primary prevention
• Infection and cancer: intervention is key
• Poverty, affluence and the global burden of
cancer
• The Western lifestyle and its health risks
Key Statements from the WHO:
• The Pap smear for cervical cancer is the single
best cancer screening procedure.
• In 2000, the last year for which global data
exists, some 400,000 women died from breast
cancer, representing 1.6 per cent of ALL
female deaths.
Discussion
• Read your section and discuss it with your
partner/group members.
• Highlight the key points and be prepared to
share them with the class.
The good news
• Early detection and a healthy diet
• (>1.1lbs of fruits/vegetables per day can lower
your risk for cancers of the digestive tract by
25%).