BISC 440 Lab 10: Signal Transduction: How Cells Communicate

Looking at the western blot result, what is your conclusion for the patient samples?

VEGF and VEGFR are overexpressed

Why can we conclude from the Western blot experiment that VEGFR signaling activity is blocked in the presence of Angomab?

VEGFR phosphorylation cannot be detected

In addition to the anti-VEGF antibody, Marie has decided to also add a VEGFR primary antibody. At which position do you expect the band for VEGFR to appear? Remember that in SDS-PAGE proteins are separated according to their molecular weight

VEGFR runs at a higher molecular weight than VEGF

What does a target cell require to respond to an extracellular signal molecule?

all options are correct: - activation of effector proteins - matching receptors - access to the ligand

Why is necessary to test Angomab in a mouse model?

all options are correct: - to test the safety and side effects of the drug - to analyze the effect on tumor growth - to investigate the effect on angiogenesis

These are biopsies of three breast cancer patients. We would like to test for the angiogenic activity in those tumors and more specifically for the involvement of VEGF and its receptor VEGFR. What do you expect to measure in those patient samples?

an increase in VEGF samples

Which of the three drugs has the strongest inhibitory effect on VEGFR signaling?

angomab

how can we easily determine VEGF expression in a western blot experiment?

by using a primary antibody targeting VEGF

What property prevents the ligands of cell-surface receptors from entering the cell? Remember that the ligands are usually secreted into the extracellular fluid or blood-stream

hydrophobicity

In which other type of cancers do you expect VEGF signaling to play a role?

in the progression of most solid tumors

what is your observation when looking at the two images?

increased number of stained blood vessels (brown) in the ductal carcinoma

Which enzyme function is responsible for phosphorylation of VEGFR?

kinase

what does the signaling protein VEGF stimulate?

mitosis

Angomab was designed to bind specifically to VEGF. Why does this inhibit VEGFR signaling?

receptor dimerization is prevented

What are molecules called that relay signals received at receptors on the cell surface to target molecules in the cytosol and/or nucleus?

second messengers

During activation, phosphate groups are added to the VEGFR. How can we identify this in a Western blot?

the phosphorylated protein is a different size and will form a distinct band

As you can see, Marie also added an anti-beta-actin antibody. Why do you think this was important?

to check if the same amount of sample was loaded on the gel

why is cancer growth dependent on an increased number of blood vessels?

to supply the tumor with oxygen and nutrients

Why is it important to incubate the cells with purified VEGF in this experiment?

to test the effect of the inhibitors on activated VEGFR

Which amino acid residues of any RTK are phosphorylated following receptor dimerization?

tyrosine