ch20 Flashcards
Gain of functions (dominant)
-gas pedals
-promote production
-lead to excess production when mutated
Loss of function (Recessive)
-brakes
-common mutation in cancer cells
-can’t detect errors when mutated leading to deregulation
Metastatsis
-Malignant tumors’ ability to become invasive and colonize new organs/tissues
-chew in/out of organs and tissues
-can come from one abnormal cell
Proto-oncogenes
-normal genes that help cell cycle and cell growth
-ex: Ras
Gain of function mutations
-Deletion/Point mutation in coding seq.
-Regulatory mutation
-Gene amplification
-Chromosome rearrangement
Tumor suppressor genes
-loss of function mutations
-under-activity mutation
-recessive
-brakes being mutated, the regulatory genes
Oncogenes
-mutated proto-oncogenes
-promote cancer
-dominant
-overactivity mutation
Cancers’ colon multi-step process
- Loss of APC tumor-suppressor gene
-Class II benign grows - Activation of K-ras oncogene
-Class III benign grows - Loss of tumor-suppressor gene in region of DCC
-Carcinoma develops - Loss of p53 tumor-suppressor gene
-Cancer metastasizes and spreads
Conventional therapy
Chemotherapy and radiation therapy
-rely on apoptosis
-p53 deficient cells respond poorly
-shotgun approach, not tailored to one form
-toxic to all cells, most to shorter cell cycles
-DNA replication/cytokinesis inhibitors (Taxol)
Targeted therapy
Custom-designed for specific cancer
-recognize/bind mutated genes
-Immunotherapy. Gleevec, etc.
Developing targeted therapies: Drugs
Gleevec:
-binds to active kinase and can deactivate it
-administered orally
Developing targeted therapies: Inhibitors
Raf kinase inhibitors target B-Raf
Immunotherapy
-treatable by enhancing immune responses
-T-cells are immune cells killing foreign antigens
-display neo-antigens (foreign antigen)
-enhance, enrich, and expand population of T-cells
At the molecular level, what does it mean when a cancer is resistant to radiation therapy or chemotherapy?
Resistant through:
-Additional mutations
-Gene amplification of multidrug resistance
-Cells become resistant to previous drug
