Physical interaction between MYCN oncogene and polycomb repressive complex 2 (PRC2) in neuroblastoma: Functional and therapeutic implications

This article is made available through the Brunel Open Access Publishing Fund. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.CLU (clusterin) is a tumor suppressor gene that we have previously shown to be negatively modulated by the MYCN proto-oncogene, but the mechanism of repression was unclear. Here, we show that MYCN inhibits the expression of CLU by direct interaction with the non-canonical E box sequence CACGCG in the 5′-flanking region. Binding of MYCN to the CLU gene induces bivalent epigenetic marks and recruitment of repressive proteins such as histone deacetylases and Polycomb members. MYCN physically binds in vitro and in vivo to EZH2, a component of the Polycomb repressive complex 2, required to repress CLU. Notably, EZH2 interacts with the Myc box domain 3, a segment of MYC known to be essential for its transforming effects. The expression of CLU can be restored in MYCN-amplified cells by epigenetic drugs with therapeutic results. Importantly, the anticancer effects of the drugs are ablated if CLU expression is blunted by RNA interference. Our study implies that MYC tumorigenesis can be effectively antagonized by epigenetic drugs that interfere with the recruitment of chromatin modifiers at repressive E boxes of tumor suppressor genes such as CLU.SPARKS, The Neuroblastoma Society, a Wellcome Trust grant (to A. S.), and the Italian Association for Cancer Research

Low-dose oral imatinib in the treatment of systemic sclerosis interstitial lung disease unresponsive to cyclophosphamide: a phase II pilot study.

NTRODUCTION: Pulmonary involvement represents a major cause of death of systemic sclerosis (SSc) patients. Recent data suggest that tyrosine kinase inhibitors, such as imatinib, may be a therapeutic option for SSc patients. However, preliminary published clinical trials were inconclusive about imatinib efficacy and showed side effects. The purpose of this study was to verify efficacy and tolerability of low-dose imatinib on interstitial lung disease in a cohort of SSc patients unresponsive to cyclophosphamide therapy. METHODS: Thirty consecutive SSc patients with active pulmonary involvement, unresponsive to cyclophosphamide, were treated with imatinib 200 mg/day for 6 months followed by a 6-month follow-up. A "good response" was defined as an increase of forced vital capacity (FVC) by more of 15% and/or increase of diffusing capacity of carbon monoxide (DLCO) >15% and PaO2 > 90% of initial value and high-resolution computed tomography (HRCT)-scan pattern unchanged or improved. RESULTS: Twenty-six patients completed the study. Three patients died and one patient was lost to follow-up. Four patients (15.32%) had a good response, 7 worsened and 15 had a stabilized lung disease. Overall, 19 (73.07%) patients had an improved or stabilized lung disease. After a 6-month follow-up, 12 (54.5%) of the 22 patients showed an improved or stabilized lung disease. CONCLUSIONS: Lung function was stabilized in a large proportion of patients unresponsive to cyclophosphamide therapy and a beneficial outcome emerged from the analysis of HRCT lung scans. There was no significant improvement of skin involvement, and the low dose was well tolerated. These data provide useful suggestions to design future randomized clinical trials for SSc therapeutics

S.13.1 Safety and efficacy of rituximab in SSc: an analysis from the European Scleroderma Trial and Research Group

Objectives. Objective of this multicentre, observational study was to assess effects and safety of rituximab (RTX) using the European Scleroderma Trial and Research Group (EUSTAR) cohort. Methods. EUSTAR centres were asked to provide specific data about SSc patients treated with RTX. Primary endpoints were predefined for different disease manifestations and compared between baseline and follow-up. Normally distributed data, analysed by paired t-test, are shown as mean (s.d.), and non-parametric data, analysed by Wilcoxon matched paired signed-rank test, are shown as median and interquartile range. Results. Data on 72 SSc patients treated with RTX were captured from 27 EUSTAR centres (51 females/21 males, 52 diffuse/19 limited, age 51 (44-60) years, disease duration 6 (3-10) years, 47 anti-Scl-70 positive). The most frequent RTX application scheme was 1000 mg × 2 within 2 weeks (57/72 patients). Co-treatment with other immunosuppressive drugs was reported in 28 patients. The modified Rodnan skin score (mRSS) significantly decreased vs baseline at 7 (5-9) months follow-up (n = 47, 18.2 + 10.9 vs 14.5 + 9.9, P = 0.0002). This was true for both patients with later disease stages and also for patients with earlier, extended skin fibrosis (dSSc with mRSS >16 at baseline, n = 26; 26.5 + 6.8 vs 20.4 + 8.9, P < 0.0001, reduction by 29.9%). S-HAQ was unchanged, but the European SSc activity score improved after rituximab treatment [n = 10; 3.7 (2.6-6.4) vs 1.7 (0.9-2.5), P = 0.01]. RTX had no effects on lung fibrosis (FVC, DLCO, TLC, HRCT score) in n = 11 patients with evidence for SSc-ILD. In SSc-polyarthritis patients, the DAS-28 declined at 6 months follow-up without reaching statistical significance [n = 8; 4.8 (2.5-7.5) vs 3.7 (2.6-6.6); p = 0.3]. Of 8, 5patients were RF and/or anti-CCP antibody positive. Similar results were obtained for secondary outcome measures (tender and swollen joint count, VAS, CRP, ESR). Additional positive effects of RTX were seen on SSc-related myopathy (CK levels, 273 + 177 vs 184 + 139; n = 12, P = 0.03) and on digital ulcers [total number per patient 1 (1-3) vs 0 (0-1); n = 23; P = 0.0086]. During RTX treatment 14 patients had infections, 3 serum sickness, 2 allergic reactions and 1 lung fibrosis aggravation, 29 fatigue and 9 nausea. Four patients died, one possibly related to RTX treatment (pneumonia and cardiac failure 1.5 months after RTX infusion). Conclusion. This large EUSTAR cohort study points at positive effects of RTX in particular on skin fibrosis, and suggests randomized controlled trial in SSc patient

Low-dose oral imatinib in the treatment of systemic sclerosis interstitial lung disease unresponsive to cyclophosphamide: a phase II pilot study

Introduction: Pulmonary involvement represents a major cause of death of systemic sclerosis (SSc) patients. Recent data suggest that tyrosine kinase inhibitors, such as imatinib, may be a therapeutic option for SSc patients. However, preliminary published clinical trials were inconclusive about imatinib efficacy and showed side effects. The purpose of this study was to verify efficacy and tolerability of low-dose imatinib on interstitial lung disease in a cohort of SSc patients unresponsive to cyclophosphamide therapy.Methods: Thirty consecutive SSc patients with active pulmonary involvement, unresponsive to cyclophosphamide, were treated with imatinib 200 mg/day for 6 months followed by a 6-month follow-up. A "good response" was defined as an increase of forced vital capacity (FVC) by more of 15% and/or increase of diffusing capacity of carbon monoxide (DLCO) &gt; 15% and PaO2 &gt; 90% of initial value and high-resolution computed tomography (HRCT)-scan pattern unchanged or improved.Results: Twenty-six patients completed the study. Three patients died and one patient was lost to follow-up. Four patients (15.32%) had a good response, 7 worsened and 15 had a stabilized lung disease. Overall, 19 (73.07%) patients had an improved or stabilized lung disease. After a 6-month follow-up, 12 (54.5%) of the 22 patients showed an improved or stabilized lung disease.Conclusions: Lung function was stabilized in a large proportion of patients unresponsive to cyclophosphamide therapy and a beneficial outcome emerged from the analysis of HRCT lung scans. There was no significant improvement of skin involvement, and the low dose was well tolerated. These data provide useful suggestions to design future randomized clinical trials for SSc therapeutics

Cold-dependent activation of complement: Recognition, assessment, and mechanism

Cold-dependent activation of complement (CDAC) is a phenomenon characterized by low hemolytic complement activity in chilled serum. Complement component levels are normal when measured immunologically, and there is normal hemolytic activity in EDTA plasma or serum maintained at 37°C. Little attention has been paid to CDAC except in Japan, and current unfamiliarity with it, even by clinical immunologists, can lead to confusion and unnecessary laboratory tests. A 66-year-old patient with a complex medical history is described whose complement tests showed abnormalities characteristic of CDAC. Evidence for classical complement pathway activation in the cold was obtained by CH 50 measurements, by hemolytic C4 determinations, by C4a, C3a, and C4d generation, and by quantitating complexes. A good correlation was observed among these parameters. Cryoprecipitates were absent. CDAC activity has persisted for over 5 years and is greater at 13 than at 4°C. Activation is ablated by heating at 56°C and restored by the addition of C1 to the heated serum. Adsorption by streptococcal protein G-Sepharose and precipitation by 2.5% polyethylene glycol support the hypothesis that CDAC is caused by aggregated IgG. The CDAC factor(s) also induces complement activation in normal serum but has not interfered with Raji cell or C1q binding tests or with FACS analysis. More limited studies of a second individual experiencing CDAC yielded similar results.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44843/1/10875_2004_Article_BF00920794.pd