WCCS 2016
Modelling wnt secretion for CSCC
Katharina Kober - German Cancer Research Center, Heidelberg, Germany
I presented research about how to model wnt secretion in squamous cell carcinoma. The skin is quite a complex organ and it turned out that for its continuous function there need to be several pathways to organise and fulfil the functions throughout the lifetime and amongst other signalling pathways the wnt signalling pathway plays decisive roles in controlling cell proliferation, differentiation and also stem cell maintenance and fate decisions and thereby ensures to keep the delicate balance between stem cells and stemness on the one hand and differentiation of those cells on the other hand. So besides that, the wnt signalling pathway seems to play an important role in the skin. There have already been publications studying this but this is rather controversial as they point out either the canonical wnt signalling pathway or a non-canonical wnt signalling pathway which are quite the opposite of each other. So it’s not quite clear what is ongoing in this type of cancer and we would like to model that by a system that has been established by our lab because we tried to model that by a cargo receptor named EVI which is important for the transport of all wnt proteins. By modulating this you in principle can modulate the transport of all wnts and therefore globally affect wnt signalling cascades.
How were you doing the modulation?
I have a cell line that has been generated in a mouse model and I did a CRISP knockout of EVI in either exon 1 or exon 3 of the gene and I further characterised those cells, expanded them as signal cell clones and then characterised them in vitro. Of course I validated that they do not express EVI on protein levels anymore and also that they functionally do not secrete wnt proteins anymore into the serum and they are cultured in cell culture.
Were there any distinct differences?
No, because concerning those if you knock out they basically are not able to secrete either the so-called canonical wnts that rather activate the canonical wnt signalling pathway nor the non-canonical wnt so they are not secreted anymore.
Could you tell us about the results?
We wondered then how those cells differ in cell culture now that we have a knock-out clone of the cell line that basically is a squamous cell carcinoma cell line that has been isolated from a mouse model that has been induced this cancer by chemical carcinogenesis and was then generated as a mouse SSC cell line. I tested those cells in several experiments in vitro and I found no difference between wild-type controlled cells and also EVI knock-out cells. So they completely behave the same concerning proliferation, they do not have a defect concerning viability when you assess that, for example with cell assay measuring ATP levels. They also do not differ in their composition and cell cycle so they seem to behave in vitro completely the same.
Where do you see this research leading you?
When we tried to inject those cells into mice because they originally come from mice so this is working and we saw that the EVI knock-out cells are very less tumorigenic compared to the wildtype and control cells. So this is pretty interesting and we are currently trying to find out what the reason for this might be by quantitative proteomic analysis and also by expression profiling.