BIO315H5 Lecture 27: BIO315 - Lecture 27

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5 Dec 2017
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Must be increase in cell growth to keep up with cell division. Starts with rtk at the cell plasma membrane (ex. Cells need glucose for energy and building blocks - increased glycolysis from warburg effect. Anything that participates in a positive manner in this pathway is considered a proto- oncogene because by making the overactivity of this pathway promotes cell growth. Anything that puts a break on this pathway is a tumour suppressor gene. After pathway is turned on, levels increase and p53 act as transcriptional activator of genes in cell cycle arrest and apoptosis. Reason why cancer cells are genomically instable differs between cancer types. Ex. breast cancer - high level of inactivation of brca1 and brca2 (breast cancer-associated genes). Needed to repair ds-breaks through homologous recombination, so cells wont be able to fix damaged dna. Ex. colorectal cancer - mutations of dna mismatch repair genes. Pathways have distinct upstream regulators at level of receptors.