Disassembly of PKA holoenzyme organization marks prostate cancer progression

Abstract Prostate cancer is a spatially heterogeneous disease in which signaling transitions driving progression remain poorly defined, because bulk molecular analyses obscure compartment-specific pathway alterations. To resolve spatial signaling organization within human tumors, we performed intra-patient, lesion-matched profiling of MRI-targeted biopsies from the same prostate, focusing on Protein Kinase A (PKA). Immunofluorescence across healthy, Grade Group 1, and Grade Group 4 tissues revealed progressive redistribution of PKA subunits: RIβ expression declined with basal layer disruption, whereas PKAC was redistributed to proliferating tumor cells, establishing a grade-dependent imbalance between regulatory and catalytic components. This redistribution was associated with increased phosphorylation of PKA substrates, linking subunit distribution to pathway activation. Quantitative image analysis and biochemical validation of matched suspicious and non-suspicious biopsy cores from 40 patients confirmed coordinated changes in subunit expression and elevated pathway activity. Analysis of independent proteomics datasets comprising over 400 cases further supported dysregulation of catalytic-to-regulatory PKA balance and revealed enrichment of PKA phosphorylation motifs among recurrence-associated proteins. Together, these findings define a spatial transition in PKA regulatory control and support a model in which spatial redistribution of signaling components contributes to pathway activation in heterogeneous tumors.