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  • 1
    In: Journal for ImmunoTherapy of Cancer, BMJ, Vol. 10, No. 12 ( 2022-12), p. e005002-
    Abstract: Immunotherapy in high-risk neuroblastoma (HR-NBL) does not live up to its full potential due to inadequate (adaptive) immune engagement caused by the extensive immunomodulatory capacity of HR-NBL. We aimed to tackle one of the most notable immunomodulatory processes in neuroblastoma (NBL), absence of major histocompatibility complex class I (MHC-I) surface expression, a process greatly limiting cytotoxic T cell engagement. We and others have previously shown that MHC-I expression can be induced by cytokine-driven immune modulation. Here, we aimed to identify tolerable pharmacological repurposing strategies to upregulate MHC-I expression and therewith enhance T cell immunogenicity in NBL. Methods Drug repurposing libraries were screened to identify compounds enhancing MHC-I surface expression in NBL cells using high-throughput flow cytometry analyses optimized for adherent cells. The effect of positive hits was confirmed in a panel of NBL cell lines and patient-derived organoids. Compound-treated NBL cell lines and organoids were cocultured with preferentially expressed antigen of melanoma (PRAME)-reactive tumor-specific T cells and healthy-donor natural killer (NK) cells to determine the in vitro effect on T cell and NK cell cytotoxicity. Additional immunomodulatory effects of histone deacetylase inhibitors (HDACi) were identified by transcriptome and translatome analysis of treated organoids. Results Drug library screening revealed MHC-I upregulation by inhibitor of apoptosis inhibitor (IAPi)- and HDACi drug classes. The effect of IAPi was limited due to repression of nuclear factor kappa B (NFκB) pathway activity in NBL, while the MHC-I-modulating effect of HDACi was widely translatable to a panel of NBL cell lines and patient-derived organoids. Pretreatment of NBL cells with the HDACi entinostat enhanced the cytotoxic capacity of tumor-specific T cells against NBL in vitro, which coincided with increased expression of additional players regulating T cell cytotoxicity (eg, TAP1/2 and immunoproteasome subunits). Moreover, MICA and MICB, important in NK cell cytotoxicity, were also increased by entinostat exposure. Intriguingly, this increase in immunogenicity was accompanied by a shift toward a more mesenchymal NBL cell lineage. Conclusions This study indicates the potential of combining (immuno)therapy with HDACi to enhance both T cell-driven and NKcell-driven immune responses in patients with HR-NBL.
    Type of Medium: Online Resource
    ISSN: 2051-1426
    Language: English
    Publisher: BMJ
    Publication Date: 2022
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  • 2
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2021
    In:  Cancer Research Vol. 81, No. 5_Supplement ( 2021-03-01), p. IA002-IA002
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 81, No. 5_Supplement ( 2021-03-01), p. IA002-IA002
    Abstract: Therapy resistance of metastatic tumor cells poses a major limitation to the cure of cancer. Aside from cell-intrinsic processes, the tumor microenvironment is a contributor to this problem. Senescent cells can originate from healthy cells that accumulate irreparable damage. Senescent cells cease to divide, but chronically secrete a wide range of factors that permanently alter their environment. As such, they are thought to impair tissue function and, when part of a tumor microenvironment, they are thought to accelerate tumor progression, metastazation and therapy resistance. Today, I will discuss how we identified that therapy-surviving cancer cells can develop a stem-like state, which is, at least partially, driven by exogenous signals from senescent cells. In addition, I will show how therapy-surviving cancer cells can develop a senescence-like state of their own, including an associated pro-inflammatory secretory phenotype. Given the importance of cancer stemness in therapy resistance, both senescent stromal cells and senescence-like cancer cells pose exciting candidates for therapeutic removal. When designing therapies for elimination of, we ran into a problem, which is that there is no such thing as (just) senescence. Instead, there are distinct subtypes, which are not merely caused by noise. I will show how we investigate these subtypes of senescence and how this is important for their targeted elimination. More specifically, I will highlight interaction between the damage-associated proteins FOXO4 and p53 as a pivot in the viability of a damaged type of senescence, which we call now call “scarred” senescence. We had already shown in the past (Baar .. de Keizer, Cell, 2017) that inhibition of FOXO4, or interference with its interaction with p53 using cell penetrating peptides could selectively eliminate senescent cells and target signs of aging in vivo. Today, I will show how we can use FOXO4-TP53 inhibitors against at least some therapy-surviving cancer cells. Last, I will show how we invested in optimization of these compounds to develop them towards clinical translation and how we can now very effectively eliminate certain types of therapy-surviving cancer cells. Altogether, this adds to a model where a senescent TME, as well as senescence-like cancer cells, can also promote cancer progression, migration, and therapy resistance by locally enforcing a state we called (cancer) “stem-lock”. And specific TP53-FOXO4 inhibitors may overcome this problem, thereby adding to a yin-yang treatment of damaging chemo-radiotherapy, followed by FOXO4-TP53-based anti-senescence treatment. Citation Format: Diana A. Putavet, Johannes Lehmann, Beatriz Subtil, Damon Hofman, Marjolein P. Baar, Peter L.J. de Keizer. Targeting senescence heterogeneity against cancer therapy-resistance and metastases [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr IA002.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2021
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    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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  • 3
    In: Neuro-Oncology, Oxford University Press (OUP), Vol. 25, No. Supplement_1 ( 2023-06-12), p. i69-i69
    Abstract: High-risk medulloblastoma is one of the most recalcitrant pediatric cancers, and children with MYC-amplified disease frequently succumb to relapsed disease. Extensive analyses of the coding genome in this disease have characterized additional somatic events in some subsets of patients, though most tumors lack targetable mutations and do not yield insights regarding their aggressive behavior. At the same time, medulloblastoma is known to exhibit extensive rewiring of translational control in MYC-driven tumors, consistent with recent genetic evidence that the impact of this transcription factor on control of mRNA translation may be the most critical aspect of its function during tumorigenesis. Therefore, to propose previously unknown mechanisms for this disease, we have investigated the functional impact of translation of non-canonical open reading frames (ORFs) across medulloblastoma model systems. We demonstrate that these ORFs are commonly translated in medulloblastoma model systems and patient tumors, correlating with disease subtype. Using genome-wide CRISPR/Cas9 screens, we found that ORFs are frequently essential for cell survival in medulloblastoma and describe widespread reliance on upstream open reading frames (uORFs) in particular. From these, we identify a uORF in the ASNSD1 gene that is selectively upregulated and required for maintenance of cell survival by coordinating the function of the prefoldin-like complex, a poorly understood complex implicated in post-translational control. Together, our findings provide a blueprint for oncogenic uORFs as critical disease mediators both in medulloblastoma and, by extension, human cancers more broadly.
    Type of Medium: Online Resource
    ISSN: 1522-8517 , 1523-5866
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2023
    detail.hit.zdb_id: 2094060-9
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  • 4
    In: Cell Death & Disease, Springer Science and Business Media LLC, Vol. 13, No. 11 ( 2022-11-25)
    Abstract: TP53 nonsense mutations in cancer produce truncated inactive p53 protein. We show that 5-FU metabolite 5-Fluorouridine (FUr) induces full-length p53 in human tumor cells carrying R213X nonsense mutant TP53 . Ribosome profiling visualized translational readthrough at the R213X premature stop codon and demonstrated that FUr-induced readthrough is less permissive for canonical stop codon readthrough compared to aminoglycoside G418. FUr is incorporated into mRNA and can potentially base-pair with guanine, allowing insertion of Arg tRNA at the TP53 R213X UGA premature stop codon and translation of full-length wild-type p53. We confirmed that full-length p53 rescued by FUr triggers tumor cell death by apoptosis. FUr also restored full-length p53 in TP53 R213X mutant human tumor xenografts in vivo. Thus, we demonstrate a novel strategy for therapeutic rescue of nonsense mutant TP53 and suggest that FUr should be explored for treatment of patients with TP53 nonsense mutant tumors.
    Type of Medium: Online Resource
    ISSN: 2041-4889
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2541626-1
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  • 5
    In: Blood Cancer Discovery, American Association for Cancer Research (AACR), Vol. 2, No. 5 ( 2021-09-01), p. 484-499
    Abstract: Acquisition of oncogenic mutations with age is believed to be rate limiting for carcinogenesis. However, the incidence of leukemia in children is higher than in young adults. Here we compare somatic mutations across pediatric acute myeloid leukemia (pAML) patient-matched leukemic blasts and hematopoietic stem and progenitor cells (HSPC), as well as HSPCs from age-matched healthy donors. HSPCs in the leukemic bone marrow have limited genetic relatedness and share few somatic mutations with the cell of origin of the malignant blasts, suggesting polyclonal hematopoiesis in patients with pAML. Compared with normal HSPCs, a subset of pAML cases harbored more somatic mutations and a distinct composition of mutational process signatures. We hypothesize that these cases might have arisen from a more committed progenitor. This subset had better outcomes than pAML cases with mutation burden comparable with age-matched healthy HSPCs. Our study provides insights into the etiology and patient stratification of pAML. Significance: Genome-wide analysis of pAML and patient-matched HSPCs provides new insights into the etiology of the disease and shows the clinical potential of these analyses for patient stratification. This article is highlighted in the In This Issue feature, p. 403
    Type of Medium: Online Resource
    ISSN: 2643-3230 , 2643-3249
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2021
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