UCLA Library

Prostate cancer growth is driven by androgen signaling using the androgen receptor (AR). Androgen deprivation therapy (ADT) is the gold standard for prostate cancer, but the majority of ADT-treated patients develop resistance, which often involves the loss of luminal lineage identity and AR-independent growth. Previous work has shown that modulating metabolism can regulate cell fate in many tissues. Therefore, it is important to understand the mechanisms behind how altered metabolism affects lineage identity and response to AR blockade, a common form of treatment for prostate cancer involving blocking AR signaling. Inhibition of mitochondrial pyruvate carrier 1, an essential metabolic enzyme, with small molecule UK5099 in mouse basalderived nonmalignant organoids blocked luminal differentiation and UK5099-treated organoids retained a basal phenotype. AR expression decreased substantially in vehicle-treated organoids, but had a more modest decrease in UK5099-treated organoids in castrated conditions. Expression of Tmprss2, an AR target gene, slightly decreased in vehicle-treated organoids, yet slightly increased with UK5099 treatment in castrated conditions. The organoid size assay was a useful tool in determining how modulating metabolism affected the impact of castration on organoid diameter in 3D ex vivo organoid culture. It shows that the number of days post-castration onset could affect the relative size of different treatment groups, but 6 days after castration vehicletreated organoids were smaller in castrated conditions than control conditions. Castrated UK5099-treated organoids, however, appeared slightly larger than the UK5099 control. An investigation into differentiation and metabolic pathways affected by UK5099-treatment revealed differential expression of phosphorylated p-65 (NFkB), changes in β-catenin nuclear translocation, and increased citrate synthase, OGDH, and MDH2 in the nucleus. This shows that UK5099 affects both differentiation and metabolism. Collectively, these results show that altering metabolism affects lineage identity and response to AR blockade. Modulation of metabolism appears to be a potential method of improving clinical outcomes for advanced prostate cancer.