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P66Shc deficiency in the E?-TCL1 mouse model of chronic lymphocytic leukemia enhances leukemogenesis by altering the chemokine receptor landscape.

ABSTRACT: The Shc family adaptor p66Shc acts as a negative regulator of proliferative and survival signals triggered by the B-cell receptor and, by enhancing the production of reactive oxygen species, promotes oxidative stress-dependent apoptosis. Additionally, p66Shc controls the expression and function of chemokine receptors that regulate lymphocyte traffic. Chronic lymphocytic leukemia cells have a p66Shc expression defect which contributes to their extended survival and correlates with poor prognosis. We analyzed the impact of p66Shc ablation on disease severity and progression in the E?-TCL1 mouse model of chronic lymphocytic leukemia. We showed that E?-TCL1/p66Shc-/- mice developed an aggressive disease that had an earlier onset, occurred at a higher incidence and led to earlier death compared to that in E?-TCL1 mice. E?-TCL1/p66Shc-/- mice displayed substantial leukemic cell accumulation in both nodal and extranodal sites. The target organ selectivity correlated with upregulation of chemokine receptors whose ligands are expressed therein. This also applied to chronic lymphocytic leukemia cells, where chemokine receptor expression and extent of organ infiltration were found to correlate inversely with these cells' level of p66Shc expression. p66Shc expression declined with disease progression in E?-TCL1 mice and could be restored by treatment with the Bruton tyrosine kinase inhibitor ibrutinib. Our results highlight p66Shc deficiency as an important factor in the progression and severity of chronic lymphocytic leukemia and underscore p66Shc expression as a relevant therapeutic target.

SUBMITTER: Patrussi L

PROVIDER: S-EPMC6886430 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

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p66Shc deficiency in the Eμ-TCL1 mouse model of chronic lymphocytic leukemia enhances leukemogenesis by altering the chemokine receptor landscape.

Patrussi Laura L Capitani Nagaja N Ulivieri Cristina C Manganaro Noemi N Granai Massimo M Cattaneo Francesca F Kabanova Anna A Mundo Lucia L Gobessi Stefania S Frezzato Federica F Visentin Andrea A Finetti Francesca F Pelicci Pier Giuseppe PG D'Elios Mario M MM Trentin Livio L Semenzato Gianpietro G Leoncini Lorenzo L Efremov Dimitar G DG Baldari Cosima T CT

Haematologica 20190228 10

The Shc family adaptor p66Shc acts as a negative regulator of proliferative and survival signals triggered by the B-cell receptor and, by enhancing the production of reactive oxygen species, promotes oxidative stress-dependent apoptosis. Additionally, p66Shc controls the expression and function of chemokine receptors that regulate lymphocyte traffic. Chronic lymphocytic leukemia cells have a p66Shc expression defect which contributes to their extended survival and correlates with poor prognosis. ...[more]

PMID: 30819907

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Project description:Development of chronic lymphocytic leukemia (CLL) is associated with severe immune dysfunction. T-cell exhaustion, immune checkpoint upregulation, and increase of regulatory T cells contribute to an immunosuppressive tumor microenvironment. As a result, CLL patients are severely susceptible to infectious complications that increase morbidity and mortality. CLL B-cell survival is highly dependent upon interaction with the supportive tumor microenvironment. It has been postulated that the reversal of T-cell dysfunction in CLL may be beneficial to reduce tumor burden. Previous studies have also highlighted roles for histone deacetylase 6 (HDAC6) in regulation of immune cell phenotype and function. Here, we report for the first time that HDAC6 inhibition exerts beneficial immunomodulatory effects on CLL B cells and alleviates CLL-induced immunosuppression of CLL T cells. In the Eμ-TCL1 adoptive transfer murine model, genetic silencing or inhibition of HDAC6 reduced surface expression of programmed death-ligand 1 (PD-L1) on CLL B cells and lowered interleukin-10 (IL-10) levels. This occurred concurrently with a bolstered T-cell phenotype, demonstrated by alteration of coinhibitory molecules and activation status. Analysis of mice with similar tumor burden indicated that the majority of T-cell changes elicited by silencing or inhibition of HDAC6 in vivo are likely secondary to decrease of tumor burden and immunomodulation of CLL B cells. The data reported here suggest that CLL B cell phenotype may be altered by HDAC6-mediated hyperacetylation of the chaperone heat shock protein 90 (HSP90) and subsequent inhibition of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway. Based on the beneficial immunomodulatory activity of HDAC6 inhibition, we rationalized that HDAC6 inhibitors could enhance immune checkpoint blockade in CLL. Conclusively, combination treatment with ACY738 augmented the antitumor efficacy of anti-PD-1 and anti-PD-L1 monoclonal antibodies in the Eμ-TCL1 adoptive transfer murine model. These combinatorial antitumor effects coincided with an increased cytotoxic CD8+ T-cell phenotype. Taken together, these data highlight a role for HDAC inhibitors in combination with immunotherapy and provides the rationale to investigate HDAC6 inhibition together with immune checkpoint blockade for treatment of CLL patients.

Project description:B cell chronic lymphocytic leukemia (CLL) is often preceded by a benign monoclonal or oligoclonal CD5+ B cell lymphocytosis. We have generated transgenic mice expressing a catalytically inactive, dominant-negative recombination activating gene 1 (dnRAG1 mice) in the periphery. These animals develop an early-onset indolent CD5+ B cell lymphocytosis, caused in part by a defect in secondary V(D)J rearrangements initiated to alter autoreactive B cell receptor specificity. Hypothesizing that the CD5+ B cells accumulating in dnRAG1 mice represent a CLL precursor, we crossed dnRAG1 mice with CLL-prone Eµ-TCL1 mice to determine whether dnRAG1 expression in Eµ-TCL1 mice accelerates the onset of CLL-like disease. We find that CD5+ B cell expansion and CLL progression occurs more rapidly and uniformly in double-transgenic mice (DTG mice) compared to Eµ-TCL1 mice, but with similar phenotypic and leukemogenic features. To gain insight into genes or pathways responsible for CD5+ B cell accumulation in the transgenic mice, we performed comparative gene expression profiling studies using normal and CD5+ B cells isolated from wild-type and transgenic mice at either 12 weeks of age (pre-leukemia) or at CLL onset in DTG mice (using age-matched wild-type and single-transgenic mice as controls). These analyses confirm the upregulation of tolerogenic genes in CD5+ B cells and reveal a possible role for prolactin signaling in the regulation of receptor editing. This study suggests that a failure to remodel B cell antigen receptor genes in response to autoreactivity may promote the benign accumulation of CD5+ B cells, which may then be subjected to secondary genetic lesions that promote CLL progression. dnRAG1 mice were bred to Eµ-TCL1 mice to obtain cohorts of wild-type (WT), single-transgenic (dnRAG1 and Eµ-TCL1), and DTG mice. Splenic CD19+B220hiCD5- B cells from WT mice or CD19+CD5+ B cells from transgenic mice were purified using fluorescence activated cell sorting (FACS). Biotin end-labeled cDNA prepared from the sorted cells was hybridized to Mouse Gene 1.0 ST Arrays. These experiments were performed two independent times: once with a cohort of 12-week-old mice, and once with older mice (>34 weeks old) consisting of two ill DTG mice and their age-matched counterparts. At least two biological replicates were used where possible.

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Dataset Information

P66Shc deficiency in the E?-TCL1 mouse model of chronic lymphocytic leukemia enhances leukemogenesis by altering the chemokine receptor landscape.

Publications

p66Shc deficiency in the Eμ-TCL1 mouse model of chronic lymphocytic leukemia enhances leukemogenesis by altering the chemokine receptor landscape.

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