Integrated Multi-Omics and Spatial Transcriptomics Reveal GUK1 as a Prognostic Biomarker Regulated by the TP53-HSF1...

Background: Guanylate kinase 1 (GUK1) is crucial for nucleotide metabolism, yet its impact on breast cancer (BC) progression remains poorly defined. The objective of the present study is to investigate GUK1 as a prognostic biomarker and therapeutic target. Methods: We employed a multi-omics approach integrating The Cancer Genome Atlas (TCGA) data, machine learning algorithm, High-Definition spatial transcriptomics (Visium HD), single-cell profiling, molecular docking and experimental validation including in vitro knockdown models and Surface Plasmon Resonance (SPR). Results: LASSO regression identified GUK1 as a key metabolic driver. High expression correlated significantly with poor survival and was most pronounced in Human Epidermal Growth Factor Receptor 2 (HER2)-positive and triple-negative subtypes. Spatial transcriptomics revealed GUK1 strongly colocalizes with expanding cancer cell nests, intensifying with disease stage. Single-cell analysis linked GUK1 overexpression to an immunosuppressive microenvironment enriched in exhausted T-cells. Clinically and molecularly, TP53 mutations are highly associated with HSF1 promoter hypomethylation and subsequent HSF1-mediated GUK1 upregulation. We experimentally confirmed this axis, showing that HSF1 or GUK1 knockdown significantly impaired cell migration and suppressed mTOR signaling. Furthermore, while high GUK1 levels predicted resistance to CDK4/6 inhibitors, they enhanced sensitivity to the PI3K/mTOR inhibitor Apitolisib. This therapeutic vulnerability was validated by SPR, which confirmed high-affinity binding between GUK1 and Apitolisib, and by cell viability assays where GUK1 depletion induced drug resistance. Conclusion: GUK1 serves as a robust prognostic biomarker regulated by the TP53-HSF1 axis. Its distinct spatial patterns, immune-suppressive associations, and experimentally validated role in modulating PI3K/mTOR inhibitor sensitivity position GUK1 as a promising target for precision oncology in invasive BC.