Cell Biology – Test 4 – Final – Cancer 1. Gene expression in Cancerous cells a. Mutation – sequence change in the bases of DNA b. In cancerous cells, mutations cause cells to lose control over mitosis i. Proto-oncogene – protein normally causes cells to divide, mutation causes protein to produce a higher rate of mitosis ii. Multiple changes can occur. 1. make the proto-oncogene to the oncogene (mutated version) 2. Could make copies of the same gene 3. Could cause chromosome rearrangement. iii. Tumor suppressor gene – protein normally inhibits cell division 4. If it becomes mutated, you produce a non-functional protein or quit producing it all together 5. Can lead to excessive cell survival. iv. The oncogene sends constant divide signals and the tumor suppressor genes are not stopping division, so the buildup of these cells can cause a tumor c. Two types of tumors v. Benign – mass of essentially normal cells which stays at the site of origin 6. Could have almost a “tissue covering” 7. Typically don’t cause problems unless they get large vi. Malignant – mass of “cancerous” cells that displaces normal tissue growth 8. Has the ability to move and change location 2. Number of mutations d. Most cancers require more than one mutation to occur vii. If division occurs faster, the cell doesn’t have the same amount of time to make sure everything is okay viii. Most cancers appear later in life because it takes some time for a cell to develop numerous mutations ix. Can cancer be inherited? 9. If inherit one mutation and the cancer requires four, you have a predisposition for that type of cancer 10. Higher likelihood, but not certain 3. Carcinogens- Any agent that contributes to the development of cancer e. 1761 – John Hill reported increased nasal cancers in men that used excessive tobacco snuff f. 1775 – Percival Pot reported skin cancers in scrotum of adolescent men who in youth worked as a chimney sweep g. 1915 - Specific chemical linked by Katsosaburo Yamagiwa, Used code tar to induce tumors on the ears of rabbits h. Severity and Intensity
Severity and Intensity
Ultraviolet radiation: causes breaks between A-T base pairs and creates T-T dimers
Basal Cell Carcinoma
Squamous Cell Carcinoma
Melanoma Melanoma
Instead of UV hitting the cell, it hits the melanoma of the cell, which increases its production to protect DNA during process such as tanning i. Chemical carcinogens examples: smoke, red dye #2, asbestos--- There are 49 carcinogens in tobacco smoke including: nitrosamine, formaldehyde, arsenic, nickel, cadmium and benzopyrene j. Viruses---did not transplant cells, just viruses that caused cancer x. Insertion of viral oncogene
Produce viral oncogene protein or produce a protein that can influence adjacent genes.
If the oncogene is viral, it continues to signal cell division, with is carcinogenic virus attached. xi. Inserts near a cellular proto-oncogene
Cellular DNA under the control of the viral promoter 4. Normal Tissue k. Epithelial Sheets: Polarized cells that rest on a basal lamina with an exposed surface 11. Chemically different 12. Organization top and bottom 13. Neighboring cells maintain connections with each other and the basal lamina. l. Connective tissue is extracellular matrix 14. Matrix components are produced inside the cell and secreted 15. Collagen fibers: Protein that provides strength 16. Collagen matrix bound to actin of the cytoskeleton, fibronectin, and integrin. 5. Changes in Cancerous Tissue m. Uncontrolled Cell Division