Microbiology - Shillitoe - Oncogenic Viruses Flashcards
Malignant cells have a number of differences from normal cells. Name them (6)
- Tumorigenicity
- Lack of differentiation
- Immortality
- Lack of contact inhibition
- Resistance to apoptosis
- Chromosome abnormalities
Growth of cells is controlled y proto-oncogenes, ie:
myc - transcription factor
sis - platelet-derived growth factor
erb B - growth factor receptor
The cell cycle is regulated by numerous proteins such as:
p53 - inactivated by viral proteins
pRB - retinoblastoma protein can be inactivated by viral proteins
How is DNA damage normally managed?
Pause in the cell cycle
Attempted repair of DNA damage
Resumption of the cell cycle or apoptosis
T/F: For a cell to be malignant, it must be necessary for several genes to have changed.
True
What are two ways retroviruses cause cancer in animals?
- Some viruses contain the oncogenes and express tem inside cells
- Some can insert their promoter into a chromosome and cause expression of regional oncogenes
T/F: Oncogenic viruses are species-specific
True
SV40 causes cancer in what animals?
Rodents
Expresses T-antigen which inactivates p53 and pRB but does not cause cancer in humans
In what species do adenovirus serotypes cause cancer?
Rodents
In humans, just a cold
High risk HPV (16, 18) cause what cancers?
Cervical cancer
Penile cancer
Oropharyngeal cancer
E6 and E7 genes function the same at T antigen in SV40
What cancers does EBV cause?
EBV is a herpes virus that causes Burkitt’s lymphoma (childhood) in Africa and AIDS patients, and naso-pharyngeal cancer in Asia
*cofactors involved ie food items in Asia, and malaria in Africa
What is human T-cell lymphotrophic virus (HTLV-1 and HTLV-2)
RNA virus but with no oncogene tax gene --> overexpression of interleukin-2 and its receptor Blood borne Prevalent in Caribbean countries Causes leukemia and lymphoma
Kaposi’s sarcoma and EBV ars both what kind of virus?
Herpes
Kaposi’s is HHV8
EBV is HHV6
