Facen, E. | Search bioRxiv

bioRxiv2025

NNMT is a biomarker of prostate cancer cells with a mesenchymal phenotype and induces sensitivity to metabolic agents

Nicotinamide phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme in the NAD+ salvage pathway and a promising therapeutic target in cancer. Resistance to NAMPT inhibitors, such as FK866, remains a key limitation to their clinical translation. While acquired resistance in cancer cell lines has been linked to target mutations, increased drug efflux and metabolic reprogramming, innate resistance mechanisms have been poorly studied. Addressing this gap is essential for identifying patient subgroups most likely to benefit from NAMPT-targeted therapies. Advanced castration resistance prostate cancer (CRPC) lacks effective targeted treatments. Among its heterogeneous subtypes, stem cell-like CRPC (CRPC-SCL) is defined by androgen receptor (AR) independence, YAP/TAZ dependency, and mesenchymal traits. In this study, we identify the YAP/nicotinamide N-methyltransferase (NNMT) axis as a key mediator of innate sensitivity to FK866 in stem-like mesenchymal CRPC cells. Using genetic and pharmacological models, we show that YAP or NNMT silencing rescues mesenchymal CRPC cells from FK866-induced apoptosis, endoplasmic reticulum stress, and NAD(H) loss. Metabolomic profiling confirmed that NNMT activity depletes nicotinamide, sensitizing cells to FK866. We further validated NNMT upregulation across clinical CRPC- SCL datasets, where it strongly correlates with mesenchymal and therapy-resistant phenotypes, as well as in murine prostate cancer cells with mesenchymal/stemness phenotypes. In conclusion, we identify the YAP/NNMT axis as a determinant of innate sensitivity to NAMPT inhibition in prostate cancer. These findings support the use of NNMT as a predictive biomarker for NAD+-targeting therapies and provide mechanistic insight into a metabolic vulnerability of the CRPC-SCL subtype. Targeting the YAP/NNMT/NAMPT axis may represent a novel strategy for treating stem-like/mesenchymal, therapy-resistant prostate cancers. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/651153v2_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@de4237org.highwire.dtl.DTLVardef@1cd577corg.highwire.dtl.DTLVardef@2aa97corg.highwire.dtl.DTLVardef@dd2ac0_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2023

HuR modulation with tanshinone mimics impairs LPS response in murine macrophages

Lipopolysaccharide exposure to macrophages induces an inflammatory response that is heavily regulated at the transcriptional and post-transcriptional levels. HuR (ELAVL1) is an RNA binding protein that binds and regulates the maturation and half-life of AU/U rich elements (ARE) containing cytokines and chemokines transcripts, mediating the LPS-induced response. Here we investigated how and to what extent small molecule tanshinone mimics (TMs) inhibiting HuR-RNA interaction counteract LPS stimulus in macrophages. We show TMs exist in solution in keto-enolic tautomerism and that, by molecular dynamic calculations, the orto quinone form is the bioactive species interacting with HuR and inhibiting its binding mode vs mRNA targets. A chemical blockage of the diphenolic, reduced form as a diacetate caused the loss of activity of TMs in vitro but resulted to prodrug-like activity in vivo. The murine macrophage cell line RAW264.7 was treated with LPS and TMs, and the modulation of cellular LPS-induced response was monitored by RNA and Ribonucleoprotein immunoprecipitation sequencing. Correlation analyses indicated that LPS induced a strong coupling between differentially expressed genes and HuR-bound genes, and that TMs reduced such interactions. Functional annotation addressed a specific set of genes involved in chemotaxis and immune response, such as Cxcl10, Il1b, Cd40, and Fas, with a decreased association with HuR, a reduction of their expression and protein secretion. The same effect was observed in primary murine bone marrow-derived macrophages, and in vivo in an LPS induced peritonitis model, in which the serum level of Cxcl10 and Il1b was strongly reduced, endowing TMs such as TM7nox with remarkable anti-inflammatory properties in vivo.

molecular biology↗