Dr. J Specific Topics Flashcards
How many viruses induce cancer?
2 RNA and 5 DNA viruses
Majority of the RNA viruses belong to which family?
Retrovirdae Family
How many retroviruses induce human cancer and what are they?
Only one retrovirus induces cancer and it is Human T cell Leukemia Virus 1-HTLV-1
Which virus is the only non-retroviral RNA virus that induces cancer in humans?
Hepatitis C
What are the 5 DNA viruses that induce cancer in humans?
EBV HHV8 HBV HPV MCV
What are the two RNA viruses that induce cancer in humans?
HTLV
HCV
What percent of human cancers worldwide are caused by oncoviruses?
12 (Prevelance in US)
T/F
RNA viruses are associated with breast cancer?
False
What are the diseases caused by Epstein Barr Virus EBV?
Burkitt Lymphoma
Nasopharyngeal carcinoma
Hodgkin disease
Gastric Carcinoma
What are the disease caused by HHV8?
Kaposi sarcoma
Multicentric Castleman disease
Primary Effucsion lymphoma
What are the diseases caused by Human Papilomavirus HPV16 and HPV18?
Cervical Carcinoma
Other anogenital carcinomas
Oropharyngeal carcinoma
Non-melanoma skin cancer
What are the diseases cause by Merkel Call Polyomavirus MCV?
Merkel Cell Carcinoma
What are the diseases caused by Hepatitis B Virus HBV or Hepatitis C virus HCV?
Hepatocellular carcinoma
What are the diseases caused by T-lymphotropic retrovirus HTLV?
Adult T cell leukemia/lymphoma
T/F
Oncoviruses are necessary but not sufficient for human cancer development
True
This means that viral infection does not always cause cancer. the percentages are low even though viral infections high
T/F Viral cancers are associated with persistent infection and occur immediately after acute infection
False
Occur many years after acute infection
What are the two things involved in cancer development?
Environment and host co-factors (immunosuppression, genetic predisposition or mutagens)
What can play a deleterious or protective role with some human virus- associated cancers increasing with immunosuppression and other appearing in the context of chronic inflammation?
Immune System
What is the first step before viral tumorigenesis?
Transformation (In vitro)
This is a development of immortal cells in cell culture
What is oncogenesis?
development of tumor in animals/humans
T/F
All transformed cells are oncogenic
False
What are the features of transformed cells?
- majority tumorigenic (produce cancer in host)
- immortal,
- loss of contact inhibition When they come into contact/touch each other on the plate they will NOT stop dividing, producing a very dense spot of cells on the plate.
- anchorage independent, meaning they can break off and go into solution or semi-soluble agar.
- Most are growth factor independent or have a reduced dependence on growth factor.
- Despite the fact that they may be nutrient deprived, they can still synthesize their DNA
- aerobic glycolysis Transformed cell still have a lot of oxygen, but they switch from oxidative respiration to glycolysis. This is specific to cancer cells and transformed cell, they start to use glycolysis.
- Decreased expression of fibers
- Reduce adhesion to solid substance
- Produce more surface proteases which allows them to invade other tissues.
- so you see a redistribution of their microfilaments, which causes the change in shape, - You also see significant change in cell phenotypes. - Acidification of culture medium.
What are the characteristics of normal cells?
- An isolated normal non-tumorigenic cell taken from one organism and introduced to another will not produce a tumor.
- -They have a finite life span, they are not immortal. - They also have contact inhibition, which means when they grow on a plate, they can’t grow on top of each other. Contact with another cell inhibits this, thus the term, contact inhibition.
- They are anchorage dependent, if they aren’t blood cells they require a surface to attach to. Loss of that attachment kills them. This is a protective mechanism for cells in our body.
- They have normal nutrient transfer and normal oxidative respiration to produce ATP–Growth factor dependent-can only grow in culture with growth factor .
Hoe many proteins doe the vast majority of DNA tumor viruses encode for?
One oncoprotein that targets host cell factor
What are two of the best known host cell factors targeted by viral proteins?
p53 and Rb family members
Bothe act as tumor suppressors during the cell cycle
T/F
Viruses can persist in host cells as part of the episome after integration
True
What the activating cell cycle proteins that are targeted by viral oncoprotein?
Signal transdusing kinases and cyclin dependent kinases and phosphates
What are the cell target proteins for EBV/EBNA1 (nuclear antigen)?
RBP-Jk/CBF1, glycogen synthetase
What are the cell target proteins for EBV/LMP1 (latent membrane protein 1)?
PI3K, TNF signaling components
What are the cell target proteins for EBV/LMP2 (latent membrane protein 2)?
Src family members
What are the cell target proteins for KSHV/k-bZIP?
P53
What are the cell target proteins for KSHV/ORF 50?
P53