Question

Oxygen radicals:
Cysteine is an essential amino acid for certain pancreas cancer cells. In an experiment pancreas cancer cells were treated with an inhibitor (called IKE) of the amino acid transporter xCT. This antiporter exchanges intracellular glutamate for extracellular cystine (oxidised cysteine). Cystine is reduced to two molecules of cysteine upon entry into cells. Indicate the trend (increase, decrease, remain the same) you are expecting after treatment with IKE for the following cellular functions.

1) Intracellular levels of glutathione are likely to Choose... 2) Membrane damage is likely to Choose... Choose... increase 3) Cell death is likely to Choose... decrease 4) Cell death is likely to Choose... no change when IKE is applied together with a water soluble Vitamin E analogue. 5) Intracellular glutamate is likely to Choose...

Answer 1

1) Glutathione is synthesized in the body with the help of 2 amino acids glutamic acid (glutamate) and cysteine. Here, the transport of cysteine into the cell is blocked by the inhibitor. So, there will be a decrease in the level of glutathione inside the cell.

2) Similarly membrane damage is likely to decrease.

3) Cell death may also decrease.

4) Vitamin E acts as an antioxidant. So, cell death decreases when vitamin E is added.

5) Intracellular glutamate is likely to increase.