(A and B) Affinity of PRMT5 for FUBP1 and related truncations (M1–M10). (C) Schema for the PUBLISH competitive peptide function. PUBLISH peptide, PRMT5-mediated FUBP1 methylation abolishing peptide. (D) Effect of the PUBLISH peptide on the binding of FUBP1 to PRMT5 in vitro. His-FUBP1 was purified from E. coli, and FLAG-PRMT5 was enriched from HEK293T cell lysate. (E) Effect of the PUBLISH peptide on FUBP1 methylation in vitro. (F) Efficiency of nanocomplexes for peptide intracellular delivery. A fluorescein isothiocyanate–conjugated PUBLISH peptide (353–367 aa) was synthesized and mixed with BPAE at different BPAE/peptide weight ratios to test the delivery efficiency. (G) Intracellular effect of the PUBLISH peptide on methylation and gene expression. FUBP1 methylation status and the expression of FUBP1-regulated genes were determined with or without peptide delivery in prostate cancer cell lines. PUBLISH^WT, PUBLISH peptide (353–367 aa); PUBLISH^3K, PUBLISH peptide with R359/R361/R363K mutations. (H) Effect of the PUBLISH peptide on cell proliferation in prostate cancer cell lines. (I) Effect of the PUBLISH peptide on xenograft growth. C4-2 cells were used for xenograft assay in intact NOD/SCID mice. Nanocomplex-delivered peptide (WT or 3K) (5 μg/mL) was intraperitoneally injected every 2 days for 3 weeks after the xenograft reached approximately 150 mm³. The volume was calculated using the formula 0.5 × (length × width²). For each group of mice, n = 6. (J and K) Effect of the PUBLISH peptide on xenograft weight. Scale bar: 10 mm. Results are shown as mean ± SD. *P < 0.05, **P < 0.01; 1-way ANOVA with Tukey’s multiple-comparison test.