Four-Gene Signature Predicts Prostate Cancer Recurrence and Flags SPAG5 as Drug Target

Biochemical recurrence after radical prostatectomy signals hidden progression in prostate cancer, yet clinicians still lack dependable prognostic tools and targeted therapies for high-risk patients. A new multi-omics study, published open access in Biology Direct on 14 October 2026, reports a four-gene transcriptomic signature that stratifies patients into high- and low-risk recurrence groups and nominates the oncogene SPAG5 as a candidate therapeutic target with two small-molecule lead compounds.

The research team integrated transcriptomic and clinical data from TCGA and GEO cohorts. They identified biochemical recurrence-associated genes using DESeq2 and limma, then built a prognostic model with Cox and LASSO regression. Performance was evaluated with Kaplan-Meier survival analysis, ROC curves, calibration plots, and a nomogram. Gene set enrichment analysis and CIBERSORT were used to probe involved pathways and immune infiltration patterns.

The resulting signature combines SPAG5, LPL, ASPN, and THBS2, and it stratified patients into high- and low-risk biochemical recurrence groups with what the authors describe as robust accuracy in both training and validation cohorts. High-risk patients showed enrichment of oncogenic pathways and elevated infiltration of M2 macrophages. SPAG5 carried the highest risk coefficient in the model, drawing the team’s subsequent functional focus.

Multi-omics characterization linked SPAG5 promoter hypomethylation to its overexpression in tumors. Spatial and single-cell transcriptomic analyses showed enrichment of the gene in malignant regions and in tumor-associated cell populations. Somatic mutation analysis connected SPAG5 overexpression to TP53 mutations, adding a genomic context to the expression pattern. Across datasets, SPAG5 was significantly overexpressed in prostate cancer tissues and cells compared with controls.

Functional assays in the laboratory supported an oncogenic role. In vitro, knocking down SPAG5 suppressed prostate cancer cell proliferation, migration, and invasion and induced cell-cycle arrest at the G1 phase, while overexpression produced the opposite effects. These experiments used CCK-8 viability assays, colony formation, wound healing, Transwell migration and invasion tests, and cell-cycle analysis.

In vivo evidence came from mouse xenograft models. SPAG5 knockdown attenuated tumor growth, and the effect was partially rescued by re-expressing an shRNA-resistant form of SPAG5, a control designed to show that the observed tumor suppression was specifically attributable to SPAG5 loss rather than off-target effects of the knockdown construct.

To find chemical starting points, the team ran virtual screening for small molecules targeting SPAG5. Two compounds, (-)-hydroxycitric acid lactone and 2,4,6-trihydroxybenzoic acid, directly bound and thermally stabilized the SPAG5 protein in cellular thermal shift assays, including isothermal dose-response CETSA. Proteasome and autophagy inhibition experiments indicated that the compounds promote proteasomal degradation of SPAG5.

The compounds reduced prostate cancer cell viability while showing little effect on RWPE-1 cells, which have low SPAG5 expression. In rescue experiments, cells expressing shRNA-resistant SPAG5 restored compound sensitivity with a significantly lower IC50 than sh-SPAG5 cells, consistent with SPAG5 being the relevant target of the molecules.

The authors conclude that the four-gene signature offers a clinically applicable framework for biochemical recurrence risk stratification in prostate cancer, and that SPAG5 functions as a relevant oncogenic driver and potential therapeutic target. They characterize the two identified molecules as potential hit compounds that warrant further optimization before any targeted therapy for recurrent disease could be considered. As with all preclinical work, the compound findings rest on cell and mouse models, and clinical testing in patients remains a necessary future step.

Subject of Research: A multi-omics study identifying a biochemical recurrence gene signature and the oncogene SPAG5 as a therapeutic target in prostate cancer.

Article Title: Comprehensive multi-omics analysis reveals a robust transcriptomic signature for biochemical recurrence prediction and identifies SPAG5 as a targetable oncogene with small-molecule compounds in prostate cancer

Article References: Zeng, X., Pan, M., Qiu, Q., Hong, Y., Zhou, J., Zhou, Y., Zhu, B., Zeng, Z., Chen, M., Zhao, S.-C., & Cen, J. (2026). Comprehensive multi-omics analysis reveals a robust transcriptomic signature for biochemical recurrence prediction and identifies SPAG5 as a targetable oncogene with small-molecule compounds in prostate cancer. Biology Direct. https://doi.org/10.1186/s13062-026-01023-8

Image Credits: AI Generated

DOI: 10.1186/s13062-026-01023-8

Keywords: prostate cancer, biochemical recurrence, SPAG5, multi-omics, prognostic signature, small-molecule compounds, TP53 mutation, single-cell transcriptomics, xenograft model, drug discovery, Comprehensive, analysis