There are some studies on anti-tumor effect of NK cells with conflicting results. We want to evaluate the anti tumor effect of NK cells in vitro and in vivo. What are the key biomarkers or surface proteins which would determine the effectiveness of NK cells against tumors?
Hi Muhammad.
As you said, results are pretty conflicting, and the presence of specific subsets seems to depend on the kind of tumor. Generally, the expression of activating receptors as NKG2D, DNAM-1 and especially NCRs marks NK cells able to kill tumor cells, since their ligands are often expressed on tumors. However, the best way to check killing capability is by degranulation/cytotoxicity assays. Both can be performed by cytofluorimetry. For degranualtion assay you need an anti CD107a antibody and a secretion blocker like Brefeldin A; for cytotoxicity you need CFDA to label living cells. Cytotoxicity is more effective at high e:t ratios, degranualtion am lower ones. In both cases you need to set the co-colture conditions (incubation time, ratios, NK cells pre-activation) since the sensitivity to killing varies a lot among tumor cells.
Good luck!
Thank you Costanza Maria Cristiani for your valuable suggestions. I have additional question that if the NK cells are exposed to tumor cells, what will be the effect of tumor cells on NK cells. I mean how to validate that effect because tumors also try to escape NK cells.
For my knowledge, tumor cells can induce exhaustation in NK cells, that is a condition characterized by impaired function and an inhibited phenotype with the expression of receptors such as PD-1 and Tim-3. Also, tumor cells can overexpress and/or shed NK cell ligands, which in turn causes receptor internalization.
However, exhaustation is often mediated by other immune cells recruited in the tumor microenvironment rather by tumor cells themselves, so it is very complex to model it in vitro
- Badges
- Science topic