BCH3042 Lecture Notes - Lecture 1: Cancer Cell, Growth Factor, Cell Cycle
25 May 2018
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Lecture 1 – The Hallmarks of Cancer
Cancer
• Second only to heart disease as a cause of death
• Causes much human suffering
• Cancer results from damage to DNA → acquired (exposure to mutagens) or
inherited
• All cancers are not the same – not a single disease
• The outcome and prognosis of the cancer depends on the cell type of origin
and the tissue of origin
• The type of cancer cell will have a big impact on treatment modalities
o E.g. surgery vs chemotherapy vs no treatment
• The progression of cancer depends on the cell type in which the cancer arose
o Some more slowly growing and less likely to spread
Two main Characteristics
1. Reproduce despite normal constraints that inhibit cell proliferation and clonal
expansion
• Cancer cell loses control over the cell cycle and cell division
2. Cancer cells invade and colonise territories normally reserved for other cells
Entry into Cell Cycle is tightly regulated
• Cell divisions are not continuous
• Controlled by
o External stimuli
o Nutrient availability
• Extracellular signals intracellular biochemical response
o Cell cycle entry or
o Arrest in a G1/G0 phase
▪ Either growth promoting or inhibiting
Growth Factors
• Cells do not divide or differentiate unless stimulated by environmental stimuli
or growth factors
• Circulate in the blood
• Over 200 growth factors
• Multiple effects
o Regulation of cell cycle progression
o Cell survival
o Cell migration
o Cell death
• Balance of growth factors and their receptors
o If too much → cell growth and proliferation
• Growth factors regulate the cell cycle
o Normal and cancer cells from quiescent non-dividing state, G0
o Stimulate progression through G1
• Growth factors regulate cell death
o Withdrawal of favours apoptosis
o Presence of growth factors inhibits apoptosis
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Document Summary
Two main characteristics: reproduce despite normal constraints that inhibit cell proliferation and clonal expansion, cancer cell loses control over the cell cycle and cell division, cancer cells invade and colonise territories normally reserved for other cells. Entry into cell cycle is tightly regulated: cell divisions are not continuous, controlled by, external stimuli, nutrient availability, extracellular signals intracellular biochemical response, cell cycle entry or, arrest in a g1/g0 phase, either growth promoting or inhibiting. Benign tumours: appear under the microscope like the tissues they came from, remain localized and do not spread, usually do not cause problems unless they grow in a confined space (e. g. the brain) Malignant tumours: do not resemble the tissue or cell of origin, high levels of genetic mutations. Irregular in structure, large variable nucleus, little cytoplasm, evidence of mitosis: rapidly dividing, little specialised structures: cancer cells: immature.
