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Targeting of heme oxygenase‐1 as a novel immune regulator of neuroblastoma
Author(s) -
Fest Stefan,
Soldati Rocio,
Christiansen Nina M.,
Zenclussen Maria L.,
Kilz Jana,
Berger Elisa,
Starke Sven,
Lode Holger N.,
Engel Christoph,
Zenclussen Ana C.,
Christiansen Holger
Publication year - 2015
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.29933
Subject(s) - immune system , heme oxygenase , neuroblastoma , cancer research , biology , zinc protoporphyrin , regulator , effector , cytotoxic t cell , immunology , cd8 , tumor progression , heme , cancer , cell culture , biochemistry , gene , enzyme , genetics , in vitro
Heme oxygenase (HO)−1 catalyzes the degradation of cytotoxic heme into biliverdin and blocks antitumor immune responses, thus protecting cancer against host defense. Whether this scenario also applies to neuroblastoma (NB), the most common extracranial solid childhood tumor, is not known. Here, we demonstrate for the first time a prognostic relevance of HO‐1 expression in samples from NB patients and show that targeting of HO‐1 prevents both cancer resistance against cellular stress and immune escape in the syngeneic NXS2 A/J mouse model of NB. High HO‐1 RNA expression in NB tissues emerged as unfavorable prognostic marker, in particular for patients older than 18 months as indicated by univariate as well as multivariate survival probability analyses including disease stage and MYCN status. On the basis of this observation we aimed to target HO‐1 by systemic as well as tumor‐specific zinc protoporphyrin‐mediated HO‐1 suppression in a syngeneic immunocompetent NB mouse model. This resulted in 50% reduction of primary tumor growth and a suppression of spontaneous liver metastases. Importantly, HO‐1 inhibition abrogated immune cell paralysis affecting CD4 and CD8 T‐effector cells. This in turn reverted HO‐1‐dependent immune escape mechanisms in NB by increasing NB apoptosis and improved DC maturation. In summary, HO‐1 emerges as a novel immune regulator in NB and emerges as a promising target for the development of therapeutic approaches.