Immune rewiring in prostate cancer through the CRISP3 and PSP94 induced modulation of P2RX7

Prostate secretory proteins play a pivotal role in shaping the tumor immune microenvironment by regulating cytokine maturation and macrophage behaviour, which influences whether the tumor niche becomes pro-inflammatory or immunosuppressive. In prostate cancer, dysregulation of CRISP3 (Cysteine-Rich Secretory Protein 3) and PSP94 (Prostate Secretory Protein of 94 amino acids) is strongly associated with aggressive disease phenotype, poor prognosis and recurrence, yet their mechanistic interplay has remained unclear. This study reveals a novel pathway through which CRISP3 suppresses the expression and function of the inflammasome-linked purinergic receptor, P2RX7, in prostate cancer cell lines and THP-1 derived macrophages. Using qRT-PCR, immunoblotting, LDH cytotoxicity assays, IL-1β ELISA, JNK phosphorylation and stress-response antibody array, we show that CRISP3 dampens ATP-induced cytotoxicity. PSP94, which interacts with CRISP3, reverses these effects by preventing its cellular uptake. Mechanistically, CRISP3 upregulates the levels of a transcriptional co-regulator, CITED2, which sequesters p300 and suppresses P2RX7 transcription. PSP94, when bound to CRISP3, disrupts the CRISP3-CITED2-P2RX7 regulatory axis, restoring the receptor expression and ATP responsiveness. Co- immunoprecipitation, confocal imaging, in silico promoter analysis followed by CUT&RUN collectively confirmed the involvement of this pathway in driving tumor-macrophage crosstalk and modulating immune response. Overall, the study identifies a previously uncharacterized regulatory circuit in which CRISP3 represses P2RX7 via CITED2 and PSP94 counterbalances this repression. These findings position this axis as a potential therapeutic target for modulating immune responses in prostate cancer.