The treatment of low-risk primary prostate cancer entails active surveillance only, while high-risk disease requires multimodal treatment including surgery, radiation therapy, and hormonal therapy. Recurrence and development of metastatic disease remains a clinical problem, without a clear understanding of what drives immune escape and tumor progression. Here, we comprehensively describe the tumor microenvironment of localized prostate cancer in comparison with adjacent normal samples and healthy controls. Single-cell RNA sequencing and high-resolution spatial transcriptomic analyses reveal tumor context dependent changes in gene expression. Our data indicate that an immune suppressive tumor microenvironment associates with suppressive myeloid populations and exhausted T-cells, in addition to high stromal angiogenic activity. We infer cell-to-cell relationships from high throughput ligand-receptor interaction measurements within undissociated tissue sections. Our work thus provides a highly detailed and comprehensive resource of the prostate tumor microenvironment as well as tumor-stromal cell interactions.

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is a second generation exportin-1 (XPO1) inhibitor with potent activity against acute lymphoblastic leukemia (ALL) in pre-clinical models and with minimal effects on normal cells. In this study, we evaluated if KPT-8602 would synergize with dexamethasone, vincristine or doxorubicin, three drugs currently used for the treatment of ALL. Experimental designFirst, we searched for the most synergistic combination of KPT-8602 with dexamethasone, vincristine or doxorubicin in vitro in both B-ALL and T-ALL cell lines using proliferation and apoptosis as a readout. Next, we validated this synergistic effect by treatment of clinically relevant B-and T-ALL patient derived xenograft models (PDX) in vivo. Finally, we performed RNA-sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq) to determine the mechanism of synergy. Results KPT-8602 showed strong synergism with dexamethasone on human B-ALL and T-ALL cell lines as well as in vivo in three patient-derived ALL xenografts. Compared to single drug treatment, the drug combination caused increased apoptosis and led to histone depletion. Mechanistically, integration of ChIP-seq and RNA-seq data revealed that addition of KPT-8602 to dexamethasone enhanced the activity of the glucocorticoid receptor (NR3C1) and led to increased inhibition of E2F mediated transcription. We observed strong inhibition of E2F target genes related to cell cycle, DNA replication and transcriptional regulation. ConclusionOur pre-clinical study demonstrates that KPT-8602 enhances the effects of dexamethasone to inhibit B-ALL and T-ALL cells via NR3C1 and E2F mediated transcriptional complexes, allowing to achieve increased dexamethasone effects for patients.