Biobank of genetically defined murine prostate cancer tumoroids uncovers oncogenic pathways and drug vulnerabilities driven by PTEN-loss

Prostate cancer (PCa) is the second most common cancer in men and shows high inter- and intra-patient heterogeneity. Thus, treatment options are limited and there is a lack of representative preclinical models. Here we establish a biobank of murine organoids and tumoroids that reflect common patient mutations. The deletion of Pten alone, or in combination with Stat3, or Tp53, led to an upregulation of cancer-related pathways in organoids and in tissue-derived tumoroids. By performing a medium-throughput drug screen we identify two compounds, the PDPK1/AKT/FLT dual pathway inhibitor and tenovin-6, that effectively inhibited tumoroid growth. Additionally, these compounds inhibited the growth of several human PCa cell lines and could be used in combination with Enzalutamide. Overall, we provide evidence that murine tumoroids are versatile preclinical models for studying PCa tumorigenesis and drug sensitivities to develop novel therapeutic options for PCa patients. We derived prostate organoids from healthy mice with lox sites for Pten alone, or Pten/Stat3, or Pten/Tp53. These mice were bred with Cre-expressing mice to generate knock out mice for the respective genotypes. We then derived prostate cancer tumoroids from the tumours of Pten KO, Pten/Stat3 KO, or Pten/Tp53 KO mice. We transduced healthy organoids carrying lox sites for the respective genes in vitro with a Cre-lentivirus to induce the deletion. We then generated single clones from these KO tumoroids. We also transduced healthy organoids with a non-functional Cre as a control and derived single clones from those. Differential gene expression was done on biological replicates for all wildtype and KO genotypes or single clones (N=3).