MCB 132 Bio of Cancer Lecture 4, 5
(Proto-oncogene activation I & II)
Weinberg hypothesis & experiment – Answer✅️ ☑️human cancer cells forms
of endogenous cell genes, altered cause cancer (no outbreaks of cancer
like with pathogens due to viruses, carcinogenic studies show own
genome which is big deal)
Experiment
- cancer genes into normal, screen for transformants
- ID oncogenes that transformed the cell
Weinberg’s challenges – Answer✅️
☑️1) how get DNA from cancer into
normal
2) cancerous DNA into what normal cells
3) how foreign DNA can be ID with which cancer cells
Transfection – Answer✅️
☑️- introduce DNA into cells
- address Weinberg challenge get DNA from cancer cells to normal
- removes story of virus in cancer
Weinberg Experiment – Answer✅️
☑️1) Transfection
- get cancer genes into normal cells (isolate individual genes in cancer,
sprinkle 1 per well), remove virus from story
- calcium phosphate precip or liposomes
- 0.1% integrates, small fraction
, 2) Recipient cells
- “normal” cells 3T3 (can’t proliferate high density)
3) Cloning activated oncogene
- Alu sequence copies ID human oncogene (transfected together)
3T3 cells – Answer✅️
☑️- already immortalized, subcultured mouse embryo
fibroblasts (MEF)
- at high density, can’t proliferate (non-transformed)
- poised to be transformed (only one more gene, which means 0.1%
transformation method ensures generally one gene)
DIAGRAM
- Primary cell (normal straight from organism) won’t work
3T3 vs 3T12 – Answer✅️
☑️DIAGRAM
- both initial cell death before rebounding
- immortalized state
3T3
- Arrest at high densities
3T12
- overcame contact inhibition
- can form tumors in mice
Alu sequence – Answer✅️ ☑️old viral sequences scattered throughout
genome, distinct from mice
- ID oncogenes with hybridization
(Proto-oncogene activation I & II)
Weinberg hypothesis & experiment – Answer✅️ ☑️human cancer cells forms
of endogenous cell genes, altered cause cancer (no outbreaks of cancer
like with pathogens due to viruses, carcinogenic studies show own
genome which is big deal)
Experiment
- cancer genes into normal, screen for transformants
- ID oncogenes that transformed the cell
Weinberg’s challenges – Answer✅️
☑️1) how get DNA from cancer into
normal
2) cancerous DNA into what normal cells
3) how foreign DNA can be ID with which cancer cells
Transfection – Answer✅️
☑️- introduce DNA into cells
- address Weinberg challenge get DNA from cancer cells to normal
- removes story of virus in cancer
Weinberg Experiment – Answer✅️
☑️1) Transfection
- get cancer genes into normal cells (isolate individual genes in cancer,
sprinkle 1 per well), remove virus from story
- calcium phosphate precip or liposomes
- 0.1% integrates, small fraction
, 2) Recipient cells
- “normal” cells 3T3 (can’t proliferate high density)
3) Cloning activated oncogene
- Alu sequence copies ID human oncogene (transfected together)
3T3 cells – Answer✅️
☑️- already immortalized, subcultured mouse embryo
fibroblasts (MEF)
- at high density, can’t proliferate (non-transformed)
- poised to be transformed (only one more gene, which means 0.1%
transformation method ensures generally one gene)
DIAGRAM
- Primary cell (normal straight from organism) won’t work
3T3 vs 3T12 – Answer✅️
☑️DIAGRAM
- both initial cell death before rebounding
- immortalized state
3T3
- Arrest at high densities
3T12
- overcame contact inhibition
- can form tumors in mice
Alu sequence – Answer✅️ ☑️old viral sequences scattered throughout
genome, distinct from mice
- ID oncogenes with hybridization
