Yangbai Lu ¹ Jinfeng Wu ² Xianzhe Li ^3,4 Qu Leng ^1* Jian Tan ^1,2 Hongxing Huang ¹ Rui Zhong ^1* Zhenjie Chen ^1* Yongxin Zhang ^5*

• ¹ Department of Urology, Zhongshan People's Hospital, Zhongshan, China
• ² First Clinical Medical College, Guangdong Medical University, Zhanjiang, China
• ³ Division of Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Baden-Württemberg, Germany
• ⁴ Institute of Pharmacology, Medical Faculty Heidelberg, University of Heidelberg, Heidelberg, Baden-Württemberg, Germany
• ⁵ Department of Magnetic Resonance Imaging, Zhongshan City People's Hospital, Zhongshan, China

Background: Prostate cancer (PCa) is one of the most common malignancies of the urinary system.Cuproptosis, a newly discovered form of cell death. The relationship between cuproptosis-related long non-coding RNAs (ClncRNAs) related to PCa and prognosis remains unclear. This study aimed to explore the clinical significance of novel ClncRNAs in the prognostic assessment of PCa.Methods: ClncRNAs and differentially expressed mRNAs linked to these ClncRNAs were identified using Pearson's correlation and differential expression analyses. A prognostic signature (risk score) comprising three ClncRNAs was established based on multivariable Cox regression analysis. The predictive performance of this ClncRNAs signature was validated using receiver operating characteristic curves and nomograms. Finally, further in vitro cell experiments were conducted for validation, including quantitative polymerase chain reaction (qPCR), western blot (WB), cell proliferation assays, cell migration assays, cell invasion assays, apoptosis, and cell cycle analysis.We constructed a prognostic signature of ClncRNAs for PCa comprising three key differentially expressed ClncRNAs(AC010896-1, AC016394-2, and SNHG9). Multivariable Cox regression analysis indicated that clinical staging and risk scores of the ClncRNAs signature were independent prognostic factors for PCa. Compared to other clinical features, the ClncRNAs signature exhibited higher diagnostic efficiency and performed well in predicting the 1-, 3-, and 5-year progression-free intervals (PFIs) for PCa. Notably, in terms of immune activity, PCa patients with high-risk scores exhibited higher tumor mutational burden (TMB) levels, while their Tumor Immune Dysfunction and Exclusion (TIDE) scores were lower than those of PCa patients with low-risk scores.Additionally, in vitro cellular functional experiments, we knocked down SNHG9 that is the most significantly differentially expressed ClncRNA among the three key ClncRNAs. SNHG9 knockdown resulted in a significant increase in G1 phase cells and a decrease in S and G2 phases, indicating inhibition of DNA synthesis and cell cycle progression. Colony formation assays showed reduced clonogenic ability, with fewer and smaller colonies. Western blot analysis revealed the upregulation of the key cuproptosis-related mRNAs FDX1 and DLST. These findings suggested that SNHG9 promotes PCa cell proliferation, migration, and invasion.Building on the three ClncRNAs, we identified a novel prognostic signature of PCa.The ClncRNA SNHG9 can promote PCa cell proliferation, migration, and invasion.