How PPAR
downregulation of CXCR4 may act to decrease metastasis. Tumor cells typically have high levels of
CXCR4 at their cell surface. During metastasis, cancer cells that find their
way into the bloodstream lodge in tissues that have high concentrations of CXCL12
(e.g., lungs, liver, and bone marrow). CXCL12 both encourages the entry of
cells into the tissue and promotes growth of the cell population. Downregulation
of CXCR4 by PPAR activation (endogenous 15d or
thiazolidinedione drugs, TZDs) will interfere with this process and may impede
metastasis.
