Cancer Hallmarks Flashcards
What is cancer
Uncontrolled proliferation of any cell due to faulty or missing signals that result in benign or malignant tumors
What is the 2 categories of cancer causes
- Hereditary
- Environmental
What is hereditary factors influence on cancer development
<10% cancer cases
Wide range of genetic factors that can be influenced after exposure to potential carcinogens
What is the 3 environmental factors causing cancer
- Chemical
- Radiation
- Infectious agents
How does chemical exposure cause cancer
Most common
Damage DNA directly or indirectly & causes cancer if key genes are affected
How does radiation exposure cause cancer
Damage DNA if exposed to UV, x-ray or gamma radiation
How does infectious agents cause cancer
Virus integrate into host DNA & effect gene expression
Bacteria cause chronic inflammation
What occurs in the G1 & S phase
G1: cell growth
S: DNA replication
What is the functions of control points
Ensure DNA integrity & if DNA errors the cycle will stop/repair/apoptosis
What control G1/S transition
P53
What proteins control transition between phases
Mitosis promoting factors, MPF
What is MPF’s composition
Protein dimer made of cyclin & cyclin dependent kinase (Cdk)
How does MPF become activated
Cyclin binds to Cdk & activated Cdk to phosphorylated other proteins causing activation & degradation of other proteins & cell transition between phases
What is the protein dimer is present mid G1
Retinoblastoma protein & transcriptional factor E2F
How does activation of pRB happen
After activation of Cdk it targets pRB that is phosphorylated & cause confirmation changes & E2F is released, activated & can bind to upstream genes that initiate expression of other cycling & genes form DNA replication
What is cyclin E effect on increasing own transcription
Phosphorylate more pRB to further activate E2F & promote more cyclone E expression or increase own expressions
What is cyclin E function
Progress cell cycle from G1 to S phase when interacting with Cdk2
What is somatic mutation theory
Over time exposure accumulation of multiple mutations in different genes but same cell that forms cancer cells
What is the 3 types of cancer therapy
Surgery
Radiation therapy
Chemotherapy
What is HPV effect on the cell cycle
Express E6 & E7 that inactivate regulatory gene products p53 & pRB
What is E7 effects on cell cycle
E7 binds to pRB & can’t bind E2F & released from pRB & bind promotor of target genes & transcribed gene products drive cell into S phase
What is E6 effects on cell cycle
E6 produce a protein that binds & inactive p53 that promotes unregulated cell division, cell growth, cell survival all characteristics of cancer
What is the normal function of p53
Prevent cell growth & promote cell death when there is DNA damage
Upregulate p21 protein which block formation of cyclin D & Cdk4 complex that prevent pRB phosphorylation that halts the cell cycle progression by preventing activation of E2F
What is HPV net effect on cell
Increased proliferation & avoidance of apoptosis despite DNA damage that can result in cervical cancer
