Clinical significance of HO-1 and 14-3-3ζ/δ interaction in prostate cancer

SOFIA LAGE VICKERS; PABLO SANCHIS; JUAN BIZZOTTO; AYELEN TORO; ALEJANDRA PAEZ; PIA VALACCO; JAVIER COTIGNOLA; ELBA VAZQUEZ; GERALDINE GUERON

Congreso; LXVI Reunión Anual de la Sociedad Argentina de Investigación Clínica.; 2021

Prostate Cancer (PCa) cells display abnormal expression of proteins resulting in an augmented capacity to resist chemotherapy and colonize distant organs. We have previously showed that heme-oxygenase 1 (HO-1), encoded by the gene HMOX1, has a strong anti-tumoral effect in PCa. We propose that HO-1 and its interactors reprogram PCa cells, favoring a less aggressive phenotype. In this work, we undertook a mass spectrometry-based proteomics analysis to identify HO-1 molecular partners which might collaborate with its modulatory function in PCa. PCa cells were transiently transfected with GSTHO-1 or control and treated with the stressor agent H2O2. Immunoprecipitated protein complexes were subjected to LC-ESI MS/MS. We identified TRIM28, HNRNPA2B1, HSPB1, CBX1, CBX3, MATR3, NPM1, DDB1, HMGA1, 14-3-3ζ/δ and ZC3HAV1, among the HO-1 interactors with nuclear localization. We next performed correlation analysis using open-access PCa patient datasets between HMOX1 and the selected candidates, in order to assess their clinical significance. Results show a significant and positive Spearman correlation between HMOX1 and 6 of those genes, and an increased relapse-free survival in PCa patients with high expression of those genes. Alternatively, HMOX1 and YWHAZ (14-3-3ζ/δ encoding gene and a strong predictor of PCa aggressiveness) showed a significant negative correlation. Moreover, PCa patients with high expression of YWHAZ, showed a higher risk of relapse. We then validated our proteomics approach by co-immunoprecipitation analysis, ascertaining HO-1 and 14-3-3ζ/δ interaction. Immunofluorescence assays provided evidence that HO-1 and 14-3-3ζ/δ co-localize in the cell nuclei under oxidative stress conditions. In summary, we describe a novel protein interaction between HO-1 and 14-3-3ζ/δ in PCa and highlight the clinical correlation of these two proteins pointing out to a potential inhibitory role of HO-1 on 14-3-3ζ/δ, for future therapeutic avenues.