Heme oxygenase 1 (HO-1): an auspicious target for state of the art anti-angiogenic therapeutic strategies and new insights in prostate carcinogenesis

GUERON GERALDINE; FERRANDO MERCEDES; ELGUERO BELÉN; GIUDICE JIMENA; SALLES ANGELES; LABANCA ESTEFANIA; JAWORSKY FELIPE; COLOMBO LUCAS; MEISS ROBERTO; NAVONE NORA; DE SIERVI ADRIANA; VAZQUEZ ELBA

Chicago

Congreso; AMERICAN ASSOCIATION FOR CANCER RESEARCH (AACR) ANNUAL MEETING; 2012

MERICAN ASSOCIATION FOR CANCER RESEARCH (AACR)

Prostate cancer (PCa) is a leading cause of death among males. Angiogenesis is critical during tumor initiation and progression. The arrival of anti-angiogenic agents as cancer treatments joining the ranks of surgery, chemotherapy and radiotherapy has been a source of renewed hope. Heme oxygenase-1 (HO-1) counteracts oxidative and inflammatory damage. It has become increasingly clear that in addition to its effect on blocking proliferation, invasion and migration, other mechanisms including a direct effect on angiogenic factors may account for its anti-tumoral role in PCa. To further assess its properties, we investigated its potentiality to modulate PCa associated-angiogenesis. In the present study, we identified in PCa cells a set of inflammatory and pro-angiogenic genes down-regulated in response to HO-1 overexpression, in particular VEGFA, VEGFC, HIF1α, KDR and α5β1 integrin. Our results indicated also that HO-1 counteracts oxidative imbalance reducing ROS levels. An in vivo angiogenic assay showed that intradermal inoculation of PC3 cells stable transfected with HO-1 (PC3HO-1) generated tumours less vascularised than controls, with decreased microvessel density and reduced CD34 and MMP9 positive staining. Interestingly, longer term grown PC3HO-1 xenografts displayed reduced neovascularization with the subsequent down-regulation of VEGFR2 expression. Furthermore, using immunofluorescence and structured illumination microscopy we visualized NFκB retention in cytoplasm and demonstrated a higher rate of co-localization with HO-1 under HO-1 over-expression. These observations correlated with repressed nuclear factor κB (NF-κB)-mediated transcription from an NF-κB responsive luciferase reporter construct, induced accumulation of IκB and decreased IKK mRNA levels under HO-1 modulation. These evidences strongly suggest that HO-1 may regulate angiogenesis through this pathway. Taken together, these data supports an unprecedented role of HO-1, challenging the angiogenic-switch in prostate carcinogenesis outlining a rationale for its development as an anticancer target in PCa. Abstract # 5230.