ENVB 437 Lecture 10: Eukaryotic cells and viruses – lecture 10 (February 7th 2018)
4 Jun 2018
School
Department
Course
Professor
Eukaryotic cells and viruses – lecture 10 (February 7th,2018)
CANCER CONT’D
Midterm is February 21st 2018
Quiz is February 14th 2018-02-07
Slide 114
- Different endings
o Sarcoma
o Carcinoma
▪ Lets you know it is probably more problematic/malignant
Slide 116
- Some animal cancers, like avian cancers are more directly caused by the virus itself than the ones that occur in
humans
- Leukemia
o It was determined that it could be passed by extract
o Rous – discovered that sarcoma in bird species were a result of a virus
- HPV
o Associated with cervical cancer in humans
o Females originally were vaccinate din public school and like that, this association with HPV may be
diminishing over time
- The first mouse viruses were discovered in the 1940s
- In the 50s, 60s, and 70s it was determined that around 56 oncoviruses that were discovered
o A lot of research when into the endogenous viral sequences in birds
o These were found in humans in the 80s and the research switched in this direction
▪ Big movement out of the avian field
Slide 117
- Some of the associated viruses are DNA viruses
o HPV
o HBV
o EBV KSHV
- A lot of these viral problems became evident once HIV hit the scene
o HIV weakened the immune system which allowed these viruses to establish themselved in HIV+
individuals
o HTLV – associated with leukemias and nervous damage in the legs
- As well as the hepC virus
Slide 118
- RNA tumour viruses exhert their major effects through signalling pathway modification and enhancing
o If a cell is pushed into the cell cycle and divides, and the checkpoints are not obeyed, the copied error
is passed on which allows for further mutations and further dyregulation of the cell cycle
find more resources at oneclass.com
find more resources at oneclass.com
- These viruses often suppress the genes that are supposed to check for these checkpoints → allows the cell to
undergo mitosis and potentially copy damaged DNA into daughter cells
Slide 119
- The dominant ones in the papilloma viruses are covered in the vaccines
- The others still occur
Slide 120
- You are providing another environmental mutagen, and the cell being exposed to that may result in some
damages, and then additional damage may occur overtime
- Genetic, immunological and environmental factors all have to be in sync in order for the cancer to develop
o Apoptotic pathways in the cell not functioning for example
o DNA damage making the cell lose critical functions
- We have something like 10k to 1m mutations /day /cell that are being repaired and if not repaired then the cell
is killed off …
o The ones that are not killed off become problematic in terms of cancer
- Mutations may activate an oncogene
- Women’s reproductive cycle, allows for a lot of tissue multiplication of cells in the breat, uterus and around the
ovary …
o Estrogen stimulates mitosis in those cells which increases the number of times mitosis occurs
- Wither the virus is expressed in total or in part – in terms of the transformational process
Slide 121
- At the top, homeostasis
o Cell states are being balanced between dividing and rest
o Tumour suppressor genes balancing the growth factors
o Hormones
o Protoncogenes
▪ being held in balance
- If we tip the scale by removing some of the growth supressors, then we are tipping the scale towards the cells
surviving
o Conversely, if we have a viral oncogene being expressed on the growth side without changing the
repressors, we are tipping the scale towards mitosis
- Either:
o Removing “break’
o Increasing “gas”
Slide 122
- Normal cell division and normal apoptosis → homeostasis
- Increase cellular division, same apoptosis → increase in cell number = tumour
- Normal cell division, decreased apoptosis → increases # of cells in that tissue
Slide 123
- RN viruses are activating oncogenic functions, whereas DNA viruses are negating tumour suppressor functions
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Eukaryotic cells and viruses lecture 10 (february 7th,2018) Different endings: sarcoma, carcinoma, lets you know it is probably more problematic/malignant. Some animal cancers, like avian cancers are more directly caused by the virus itself than the ones that occur in humans. It was determined that it could be passed by extract: rous discovered that sarcoma in bird species were a result of a virus. Hpv: associated with cervical cancer in humans, females originally were vaccinate din public school and like that, this association with hpv may be diminishing over time. The first mouse viruses were discovered in the 1940s. Some of the associated viruses are dna viruses: hpv, hbv, ebv kshv. Rna tumour viruses exhert their major effects through signalling pathway modification and enhancing. If a cell is pushed into the cell cycle and divides, and the checkpoints are not obeyed, the copied error is passed on which allows for further mutations and further dyregulation of the cell cycle.
