DOI: 10.1101/2023.05.23.540590

Suppression of tumor cell lactate-generating signaling pathways eradicates murine PTEN/p53-deficient aggressive-variant prostate cancer via macrophage phagocytosis

K. K.Chaudagar H. Hieromnimon A. Kelley B. Labadie J. Shafran S. Rameshbabu C. Drovetsky K. Bynoe A. Solanki E. Markiewicz X. Fan M. Loda A. Patnaik

K. K.Chaudagar H. Hieromnimon A. Kelley ...+9 A. Patnaik

摘要

Purpose: PTEN loss-of-function/PI3K pathway hyperactivation occurs in ~50% of metastatic, castrate-resistant prostate cancer patients, resulting in poor therapeutic outcomes and resistance to immune checkpoint inhibitors across multiple malignancies. Our prior studies in prostate-specific PTEN/p53-deleted genetically engineered mice (Pb-Cre;PTENfl/flTrp53fl/fl GEM) with aggressive-variant prostate cancer (AVPC) demonstrated feedback Wnt/{beta}-catenin signaling activation in 40% mice resistant to androgen deprivation therapy (ADT)/PI3K inhibitor (PI3Ki)/PD-1 antibody (aPD-1) combination, resulting in restoration of lactate cross-talk between tumor-cells and tumor-associated macrophages (TAM), histone lactylation (H3K18lac) and phagocytic suppression within TAM. Here, we targeted immunometabolic mechanism(s) of resistance to ADT/PI3Ki/aPD-1 combination, with the goal of durable tumor control in PTEN/p53-deficient PC. Experimental design: Pb-Cre;PTENfl/flTrp53fl/fl GEM were treated with either ADT (degarelix), PI3Ki (copanlisib), aPD-1, MEK inhibitor (trametinib) or Porcupine inhibitor (LGK`974) as single agents or their combinations. MRI was used to monitor tumor kinetics and immune/proteomic profiling/ex vivo co-culture mechanistic studies were performed on prostate tumors or established GEM-derived cell lines. Results: We tested whether Wnt/{beta}-catenin pathway inhibition with LGK`974 addition to degarelix/copanlisib/aPD-1 therapy enhances tumor control in GEM, and observed de novo resistance due to feedback activation of MEK signaling. Based on our observation that degarelix/aPD-1 treatment resulted in partial inhibition of MEK signaling, we substituted trametinib for degarelix/aPD-1 treatment, and observed a durable tumor growth control of PI3Ki/MEKi/PORCNi in 100% mice via H3K18lac suppression and complete TAM activation within TME. Conclusions: Abrogation of lactate-mediated cross-talk between cancer cells and TAM results in durable ADT-independent tumor control in PTEN/p53-deficient AVPC, and warrants further investigation in clinical trials.

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