Pyruvate-lactate exchange and glucose uptake in human prostate cancer cell models. A study in xenografts and suspensions by hyperpolarized [1-13 C]pyruvate MRS and [18 F]FDG-PET.

Reprogramming of energy metabolism in the development of prostate cancer can be exploited for a better diagnosis and treatment of the disease. The goal of this study was to determine whether differences in glucose and pyruvate metabolism of human prostate cancer cells with dissimilar aggressivenesses can be detected using hyperpolarized [1-13 C]pyruvate MRS and [18 F]FDG-PET imaging, and to evaluate whether these measures correlate. For this purpose, we compared murine xenografts of human prostate cancer LNCaP cells with those of more aggressive PC3 cells. [1-13 C]pyruvate was hyperpolarized by dissolution dynamic nuclear polarization (dDNP) and [1-13 C]pyruvate to lactate conversion was followed by 13 C MRS. Subsequently [18 F]FDG uptake was investigated by static and dynamic PET measurements. Standard uptake values (SUVs) for [18 F]FDG were significantly higher for xenografts of PC3 compared with those of LNCaP. However, we did not observe a difference in the average apparent rate constant kpl of 13 C label exchange from pyruvate to lactate between the tumor variants. A significant negative correlation was found between SUVs from [18 F]FDG PET measurements and kpl values for the xenografts of both tumor types. The kpl rate constant may be influenced by various factors, and studies with a range of prostate cancer cells in suspension suggest that LDH inhibition by pyruvate may be one of these. Our results indicate that glucose and pyruvate metabolism in the prostate cancer cell models differs from that in other tumor models and that [18 F]FDG-PET can serve as a valuable complementary tool in dDNP studies of aggressive prostate cancer with [1-13 C]pyruvate.