Ecology of Cancer Flashcards
Why do we apply ecology to cancer?
Like organisms, tumours are also naturally selective in our bodies. Tumours that are more able to take advantage of their environment will more likely last longer than other cells and make up the majority of tumour cells in the body. Understanding this concept involves an ecological perspective.
What are the 3 components that lead to an invasive species?
- Species-poor habitats
- disturbed habitats
- islands (unique ecosystem with lack of predators)
What are the stages of species invasion?
- Transport (Successfully introduced or killed?)
- Establish (Established into ecosystem or killed?)
- Spread (Spread or remain local)
- Impact (High or low impact on human perspective?)
What are the reasons for a stage-based approach on invasive species?
A stage-based approach can be used to assess human activity at each step of the approach. For example, did (human activity) have any effect on the invasiveness of the species?
Summarize the ecology of cancer
Initiation of the right cancer cell in the right place at the right time allows for cancer cells to occupy a “new niche,” promoting survival and growth.
This niche involves a microenvironment with a lowered pH and recruitment of growth factors.
What is considered the “right cell”?
Cancer cells with genetic alterations/traits that allow for a survival advantage in the microenvironment. (hallmarks of cancer)
What is considered the “right place?”
Any place with excess nutrients and growth factors that fit the cancer cells’ high energy demand.
What is considered the “right time?”
Old age, any time where there is a prolonged availability of nutrients.
What is the evolutionary stable strategy
A strategy which, if every member in a population adopts it, no form of mutated strategy can invade.
e.g. Hawk vs Dove
Hawk: Always attacks
Dove: Will never attack
Thus, the outcome of resources depends on the fighters while both can coexist.
What is an evolutionary stable state
A state in a population where the genetic composition of the population remains even after a disturbance, as long as the disturbance is not too major.
What do ESS and aging have in common
Aging may be the environmental disturbance that allows for cancer invasion.
What are the key characteristics of cancer
- Self sufficiency in growth signals
- Insensitive to anti-growth signals
- Evade apoptosis
- Limitless replicative potential
- sustained angiogenesis
Describe the “niche space” mentioned earlier
As cancer cells proliferate, oxygen becomes less available to the tumour. Therefore, it uses a glycolytic metabolism to produce lactic acids, which causes a lowered pH. This excludes normal somatic cells from the microenvironment.
What is hypoxia?
Hypoxia is a condition where oxygen at some point in the body is low. This introduces hypoxia-inducing factor 1 alpha (HIF-1a). This factor is degraded in the presence of oxygen.
What does HIF-1a do?
HIF-1a stimulates vascular endothelial growth factors (VEGF) to induce angiogenesis in tumour cells when oxygen levels are low. In niche microenvironments, tumour cells will have to continue to undergo glycolytic pathways, and oxygen levels will remain low. This allows HIF-1a to promote angiogenesis within the tumour cells, keeping the rapidly proliferating cells alive.
