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LE 12-2b Growth and development 200 µm
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LE 12-2c Tissue renewal 20 µm
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Types of Cells ProliferationDifferentiation Highly differentiated cells: Quiescent cells: Highly mitotic cells:
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How to determine the cycle?
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LE 12-13a Experiment 1 S S S G1G1 When a cell in the S phase was fused with a cell in G 1, the G 1 cell immediately entered the S phase—DNA was synthesized.
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LE 12-13b Experiment 2 G1G1 M MM When a cell in the M phase was fused with a cell in G 1, the G 1 cell immediately began mitosis—a spindle formed and chromatin condensed, even though the chromosome had not been duplicated.
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Mitosis and Cancer Common and severe Some form strikes 1/3; 20% death; 20% health care costs Not a single disease Early detection and treatment is vital cell division neoplasm tumor invade neighboring tissue metastasis
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LE 12-18a Cells anchor to dish surface and divide (anchorage dependence). When cells have formed a complete single layer, they stop dividing (density-dependent inhibition). If some cells are scraped away, the remaining cells divide to fill the gap and then stop (density-dependent inhibition). 25 µm Normal mammalian cells
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LE 12-18b Cancer cells do not exhibit anchorage dependence or density-dependent inhibition. Cancer cells 25 µm
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The genetic nature of cancer The clonal nature of cancer –Analyzing the cancer and normal cells –Most happen later in life Proto-oncogenes and oncogenes Recessive oncogenes and tumor suppressor genes
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LE 12-19a Tumor Glandular tissue A tumor grows from a single cancer cell. Cancer cells invade neighboring tissue.
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LE 12-19b Cancer cell Blood vessel Lymph vessel Metastatic tumor Cancer cells spread through lymph and blood vessels to other parts of the body. A small percentage of cancer cells may survive and establish a new tumor in another part of the body.
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Searching for Oncogenes Cell cycle regulatory genes A lot of cancer are associated with DNA virus Some cancers are familial In vitro mutagenesis on cultured cells Loss of heterozygocity
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Some Oncogenes Both viral AND cellular src (Rous sarcoma v.): Prototype of a family of membrane associated tyrosine kinases –over expressed or activated in cancer Kinases: abl (abelson murine leukemia v.) trk (human colon carcinoma v.) GTPase: ras (rat sarcoma v.) Transcription factors: fos, myc (chicken sarcoma v.) EGF: erb A (avian erythroblastosis v.) EGF: epithelial PDGF: platelet - derived CSF: colony stimulating FGF: basic fibroblast
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Some Familial Cancers Rb familial polyposis coli Wilms Tumor familial breast cancer Li- Fraumeni familial cancer
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EGF EGFR-P QuiescentCell Division P53 p53-p P21 CDK2-p21 Cyclin E CDK2 Cyclin E CyclinA Rb-p Rb ras fos Jun D-cyclin, CDK 2/4/6 Rb E2F Enzymes for DNA synthesis G1S
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Figure 9.7 1.Multiple nuclei 2.Lost adhesion 3.Irregular cell shape 4.Vessel invation Therapy: 1.Vessel growth inhibitor 2.Nucleotide analog
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Figure 9.8a
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Protection against cancer: 1.Apoptosis 2.Immunity 3.Telomeres
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Cancer Protection Immunity Apoptosis normal increased growth adenoma I adenoma II adenoma III 5q gene loss ras mutation ch 18 loss carcinomametastasis ch 17 p53 other ch
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