Dugga 3 - Anticancer Flashcards
What are proto-oncogenes?
Genes that code for proteins invilved in control of cell division and differentiation. The ras gene is one example of a proto-oncogene
What is oncogenes?
Mutated proto-oncogenes, distrupting their normal function.
What is an anti oncogene?
Tumor suppresion genes. Ex TP53 that codes for the protein p35.
It is the combination of cellular defects that cause life-threatening malignant growth, what types of cellular defects?
- Abnormal signalling pathways
- Insensitivity to growth-inhibitory signals
- Abnormalities in cell cycle regulation
- Apoptosis, evasion of programmed cell death
- Limitless cell division
- Angiogenesis, Ability to develop new blood vessels
- Tissue invasion and metastasis
What is a benign cancer?
Local cancer (neoplasm)
What is it called if cancer invades other parts of the body and set up secondary tumors (Metastasis)?
Malignant
What is a growth factor?
Extracellular chemical messengers, homones, that activate protein kinase receptors in the cell membrane ==> starts a signal transduction pathway ==> cell division and cell growth is started.
What are some ways that cancercells have abnormal signalling pathways?
- Cancer cells can be growing and dividing without the presence of a growth factor. PK in the membrane is mutated and always activated. Ex: ErB-2 receptors.
- Create their own growth factor ex: PDGF
- Over expressed growth factor receptor ==> supersensitive
What does hormones like TGF-B do?
It is an external hormone that counteract the effects of stimulatory growth factors and signal inhibition of cell growth and division.
Cellular defects generating a insensitivity to TGF-B cause excesive cell divsion.
There are many targets in cell division having the possibility causing abnormalities in cell cycle regulation, what are some of these targets
- Restriction point (R) in the G1 phase
- Checkpoints, found in ex G2 before entering M
How can you control the cell cycle?
- Controlling CDK and cyclin- complexes
CDK4 and CDK6 pairs with what type of cyclin?
Cyclin D. This occurs in G1
What is the role of pRB?
pRB is a powerful growth-inhibitory molucule.
pRB normaly inactivates a transcription factor (TF). If pRB is phosporylated it cant bind to TF. TF can then bind to regions of DNA ==> transkription of specific genes that lead to the production of proteins capable of moving the cell towards the S-phase.
What are two proteins, created in G1, able to move the cell into S-phase?
cyclin E and thymidine kinase
What protein is p21 (an inhibitory protein) controlled by?
p53 derived from the anti-oncogene TP53. Mutations causing malfunctioning p53 causes cancer. In half of all human tumours the cells lack functioning p53 protiens ==> p21 is not functioning ==> modifycation of cyclin and CDK complexes failes.
