CAR T-Cell Therapy

Question 1

Talk about CAR T-Cells secreting a certain enzyme to break down the ECM

Answer 1

• Anti-GD2 CAR T-Cells engineered to express heparanase
• composition of the sub-endothelial basement membrane and ECM mainly including heparan sulphate proteoglycans (HSPGs)
• heparanase breaks down these proteoglycans

Question 2

Name another potential ECM degrading enzyme which is being researched into

Answer 2

• metalloproteinase

Question 3

How are CAR T-Cells designed in attempt to lessen the affect of ROS (and thus hypoxia?)

Answer 3

• Designed to express catalase

- Catalase provides oxygen by breaking down hydrogen peroxide into hydrogen and oxygen.

Question 4

Two types of catalase expressing CAR T-Cells which worked?

Answer 4

• anti-HER2 (human epidermal growth factor receptor)

- anti-CEA (carcinoembryonic antigen)

Question 5

What is the Warburg effect?

Answer 5

most cancer cells:

predominantly produce energy by a high rate of glycolysis followed by lactic acid fermentation in the cytosol

RATHER THAN

low rate of glycolysis followed by oxidation of pyruvate in mitochondria (as in most normal cells).

Question 6

How might the acidity in the TME be reduced?

Answer 6

Proton Pump Inhibitors (PPIs)

Question 7

How do cancer cells decrease amino acid abundance in the TME?

What did scientists do to counteract this?

Answer 7

• Cancer cells express by indoleamine 3,3 dioxygenase (IDO), an enzyme which converts tryptophan to kynurenine. (kiy - nor - e - nin)
• Scientists decreased the expression of IDO on the tumour cells by administering fludarabine and cyclophosphamide.

Question 8

How have CAR T-Cells been engineered to minimise the effects of Cancer Associated Fibroblasts (CAFs)?

Answer 8

• CARs engineered to target Fibroblast Activation Proteins on surface of CAFs (Cancer Associated Fibroblasts)
• the anti-FAP CAR T-Cells additionally encouraged endogenous CD8 + T cell (AKA Cytotoxic T cell) anti-tumour responses

Question 9

How might effects of TGF-β (tumour cytokine) be reduced?

Answer 9

• CAR T-Cells have been designed to express a dominant negative TGF-β receptor
• use of systemic blockade of TGF-β signalling

Question 10

Talk about Prostaglandin-E2 (PGE2) and CAR T-Cells

Answer 10

• Prostaglandin E2 (PGE2) is released by cancer cells and tumour associated macrophages - inhibits T-Cell activation
• by activating protein kinase A (PKA) with its G-coupled receptors
• so CAR T-Cells genetically adapted to inhibit PKA activation

Question 11

What effect does elevated levels of adenosine in the TME have on T-cell function and what can be done to solve it?

Answer 11

• inhibits T cell activation by activating PKA with it’s 2A receptor (same signalling pathway as PG-E2)
• thus genetic adaption of adenosine’s 2A receptor prevents inhibition

Question 12

What do elevated levels of potassium in the TME mean for T cells?

How have CAR T-Cells been engineered to combat elevated levels of potassium in the TME?

Answer 12

• Elevated levels of potassium, caused by tumour necrosis
• correlate with reduced uptake of nutrients
• inhibits T cells’ ability to differentiate into effector T cells
• CAR T-Cells that express a potassium channel (decreases the levels)

Question 13

4 points of how CAR T-Cells could be engineered to overcome PD-1/PD-L1 interactions?

Answer 13

• anti-PD-1 or anti-PD-L1 checkpoint inhibitor drugs (in combination therapy)
• anti-PD-1 producing ScFvs
• dominant negative PD-1 receptor (on the T cell)
• CRISPR and short hairpin RNAs used to silence genes coding for PD-1 on T-cells (although PD-1 could play a role in T-cell activation so potential issues with this)