WNT1-inducible signaling pathway protein 1 activation through C-X-C motif chemokine ligand 5/C-X-C chemokine receptor type 2/leukemia inhibitory factor/leukemia inhibitory factor receptor signaling promotes immunosuppression and neuroendocrine differentiation in prostate cancer.

The interaction between prostate cancer (PCa) cells and prostate stromal cells fosters an immunosuppressive tumor microenvironment (TME) that promotes tumor growth and immune evasion. However, the specific signaling pathways involved remain unclear. We identified a key mechanism involving the CXCL5/CXCR2 and LIF/LIFR pathways, which create a feedforward loop that enhances neuroendocrine differentiation (NED) in PCa cells and upregulates WNT1-inducible signaling pathway protein 1 (WISP1) in both cell types. WISP1 upregulation is essential for inducing immune checkpoints and immunosuppressive cytokines via LIF/LIFR signaling and STAT3 phosphorylation. This process leads to increased neuroendocrine markers, immune checkpoints, cell proliferation, and migration. Notably, WISP1 levels in patient sera correlate with PCa progression, suggesting its potential as a biomarker. Our findings elucidate the mechanisms by which reciprocal communication between PCa cells and stromal cells contributes to the formation of an immunosuppressive TME, driving the malignant progression of PCa and highlighting potential targets for therapeutic intervention.

CHRM4/AKT/MYCN upregulates interferon alpha-17 in the tumor microenvironment to promote neuroendocrine differentiation of prostate cancer.

Current treatment options for prostate cancer focus on targeting androgen receptor (AR) signaling. Inhibiting effects of AR may activate neuroendocrine differentiation and lineage plasticity pathways, thereby promoting the development of neuroendocrine prostate cancer (NEPC). Understanding the regulatory mechanisms of AR has important clinical implications for this most aggressive type of prostate cancer. Here, we demonstrated the tumor-suppressive role of the AR and found that activated AR could directly bind to the regulatory sequence of muscarinic acetylcholine receptor 4 (CHRM4) and downregulate its expression. CHRM4 was highly expressed in prostate cancer cells after androgen-deprivation therapy (ADT). CHRM4 overexpression may drive neuroendocrine differentiation of prostate cancer cells and is associated with immunosuppressive cytokine responses in the tumor microenvironment (TME) of prostate cancer. Mechanistically, CHRM4-driven AKT/MYCN signaling upregulated the interferon alpha 17 (IFNA17) cytokine in the prostate cancer TME after ADT. IFNA17 mediates a feedback mechanism in the TME by activating the CHRM4/AKT/MYCN signaling-driven immune checkpoint pathway and neuroendocrine differentiation of prostate cancer cells. We explored the therapeutic efficacy of targeting CHRM4 as a potential treatment for NEPC and evaluated IFNA17 secretion in the TME as a possible predictive prognostic biomarker for NEPC.

Targeting PKLR/MYCN/ROMO1 signaling suppresses neuroendocrine differentiation of castration-resistant prostate cancer.

Conventional treatment of prostate cancer (PCa) uses androgen-deprivation therapy (ADT) to inhibit androgen receptor (AR) signaling-driven tumor progression. ADT-induced PCa recurrence may progress to an AR-negative phenotype with neuroendocrine (NE) histologic features, which are associated with metabolic disturbances and poor prognoses. However, the metabolic pathways that regulate NE differentiation (NED) in PCa remain unclear. Herein, we show a regulatory mechanism in NED-associated metabolism dysfunction induced by ADT, whereby overexpression of pyruvate kinase L/R (PKLR) mediates oxidative stress through upregulation of reactive oxygen species modulator 1 (ROMO1), thereby promoting NED and aggressiveness. ADT mediates the nuclear translocation of PKLR, which binds to the MYCN/MAX complex to upregulate ROMO1 and NE-related genes, leading to altered mitochondrial function and NED of PCa. Targeting nuclear PKLR/MYCN using bromodomain and extra-terminal motif (BET) inhibitors has the potential to reduce PKLR/MYCN-driven NED. Abundant ROMO1 in serum samples may provide prognostic information in patients with ADT. Our results suggest that ADT resistance leads to upregulation of PKLR/MYCN/ROMO1 signaling, which may drive metabolic reprogramming and NED in PCa. We further show that increased abundance of serum ROMO1 may be associated with the development of NE-like PCa.