Posted by Jim:
Here’s a very exciting paper reporting a study I have been thinking of doing myself for a long time. I wish I had been the one to do it, but it’s great to see it with my own eyes.
They grew up cancer-susceptible mice with two diets (regular, nutrient sufficient with 0.5% Pi vs. high P in which dietary P was 2x higher, 1%Pi). Then they measured number and size of lung tumors, serum Pi levels, as well as various cellular responses, including changes in Pi transporters and indicators of cellular proliferation rate.
Animals on the high P diet had:
-higher serum Pi concentrations
– 2x (!) higher number of tumors
-2x higher expression of Pi membrane transporters
-2x higher levels for expression of cell-cycle indicators
-5x higher levels of expression of cap-dependent protein translation (e.g. ribosome production?), a strong indicator of cell proliferation
All in all, this is extremely consistent with our ideas of r/K selection in human cancer, as lung tumors (in our PLOS ONE paper link) have 2-3 times higher P content than normal tissue and seem to have evolved into tumors via pathways of mutations that result in more rapid cell proliferation (rather than ones that lead to decreased apoptosis or senescence).