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REV-ERBs, nuclear hormone receptors that regulate transcription as part of the circadian clock cell machinery, inhibit autophagy and lipogenesis in premalignant and malignant cells and impair tumour growth in vivo . Tumours restrained by REV-ERBs The circadian clock regulates many of the physiological functions of an organism. Additionally, links between the circadian clock machinery and cancer have been demonstrated. Gabriele Sulli et al . have explored this link further by unravelling the functions of REV-ERBs. These nuclear hormone receptors regulate transcription and are an essential component of the circadian clock. Treatment of cancer cells with REV-ERB agonists results in cell death, through inhibition of autophagy and de novo lipogenesis. The agonists also impaired tumour growth in vivo . The circadian clock imposes daily rhythms in cell proliferation, metabolism, inflammation and DNA damage response 1 , 2 . Perturbations of these processes are hallmarks of cancer 3 and chronic circadian rhythm disruption predisposes individuals to tumour development 1 , 4 . This raises the hypothesis that pharmacological modulation of the circadian machinery may be an effective therapeutic strategy for combating cancer. REV-ERBs, the nuclear hormone receptors REV-ERBα (also known as NR1D1) and REV-ERBβ (also known as NR1D2), are essential components of the circadian clock 5 , 6 . Here we show that two agonists of REV-ERBs—SR9009 and SR9011—are specifically lethal to cancer cells and oncogene-induced senescent cells, including melanocytic naevi, and have no effect on the viability of normal cells or tissues. The anticancer activity of SR9009 and SR9011 affects a number of oncogenic drivers (such as HRAS, BRAF, PIK3CA and others) and persists in the absence of p53 and under hypoxic conditions. The regulation of autophagy and de novo lipogenesis by SR9009 and SR9011 has a critical role in evoking an apoptotic response in malignant cells. Notably, the selective anticancer properties of these REV-ERB agonists impair glioblastoma growth in vivo and improve survival without causing overt toxicity in mice. These results indicate that pharmacological modulation of circadian regulators is an effective antitumour strategy, identifying a class of anticancer agents with a wide therapeutic window. We propose that REV-ERB agonists are inhibitors of autophagy and de novo lipogenesis, with selective activity towards malignant and benign neoplasms.

Chromatin conformation and chromatin modifications affect DNA damage response signalling and hence the associated cellular outcomes of this response. This Opinion article discusses the implications of chromatin alterations in cancer cells on DNA damage responses. The generation of DNA lesions and the resulting activation of DNA damage response (DDR) pathways are both affected by the chromatin status at the site of damaged DNA. In turn, DDR activation affects the chromatin at both the damaged site and across the whole genome. Cellular senescence and cancer are associated with the engagement of the DDR pathways and with profound chromatin changes. In this Opinion article, we discuss the interplay between chromatin and DDR factors in the context of cellular senescence that is induced by oncogenes and in cancer.

Glioblastoma (GBM) is the most common and lethal primary malignant brain tumor, containing GBM stem cells (GSCs) that contribute to therapeutic resistance and relapse. Exposing potential GSC vulnerabilities may provide therapeutic strategies against GBM. Here, we interrogated the role of adenosine-to-inosine (A-to-I) RNA editing mediated by adenosine deaminase acting on RNA 1 (ADAR1) in GSCs and found that both ADAR1 and global RNA editomes were elevated in GSCs compared with normal neural stem cells. ADAR1 inactivation or blocking of the upstream JAK/STAT pathway through TYK2 inhibition impaired GSC self-renewal and stemness. Downstream of ADAR1, RNA editing of the 3'-UTR of GM2A, a key ganglioside catabolism activator, proved to be critical, as interference with ganglioside catabolism and disruption of ADAR1 showed a similar functional impact on GSCs. These findings reveal that RNA editing links ganglioside catabolism to GSC self-renewal and stemness, exposing a potential vulnerability of GBM for therapeutic intervention.

Different mechanisms have been implicated in the induction of senescence. Two of these mechanisms, the DNA damage response, which induces a replicative checkpoint, and the formation of heterochromatic foci, which leads to transcriptional repression, are found to act together in oncogene-expressing cells. Two major mechanisms have been causally implicated in the establishment of cellular senescence: the activation of the DNA damage response (DDR) pathway and the formation of senescence-associated heterochromatic foci (SAHF). Here we show that in human fibroblasts resistant to premature p16 INK4a induction, SAHF are preferentially formed following oncogene activation but are not detected during replicative cellular senescence or on exposure to a variety of senescence-inducing stimuli. Oncogene-induced SAHF formation depends on DNA replication and ATR (ataxia telangiectasia and Rad3-related). Inactivation of ATM (ataxia telangiectasia mutated) or p53 allows the proliferation of oncogene-expressing cells that retain increased heterochromatin induction. In human cancers, levels of heterochromatin markers are higher than in normal tissues, and are independent of the proliferative index or stage of the tumours. Pharmacological and genetic perturbation of heterochromatin in oncogene-expressing cells increase DDR signalling and lead to apoptosis. In vivo , a histone deacetylase inhibitor (HDACi) causes heterochromatin relaxation, increased DDR, apoptosis and tumour regression. These results indicate that heterochromatin induced by oncogenic stress restrains DDR and suggest that the use of chromatin-modifying drugs in cancer therapies may benefit from the study of chromatin and DDR status of tumours.

REV-ERBs, nuclear hormone receptors that regulate transcription as part of the circadian clock cell machinery, inhibit autophagy and lipogenesis in premalignant and malignant cells and impair tumour growth in vivo.

Tumour suppressor genes are frequently affected by somatic alterations in cancer, and the impairment of their normal function provides a strong contribution to tumourigenesis. Short-hairpin (sh) RNA library screens have been employed as powerful genetic tools to uncover important new players in human cancer. To identify potential novel tumour suppressor genes acting in the p53 pathway, we performed an shRNA screen using a cell-based model in which only a single additional genetic event disrupting the p53 pathway is required to obtain in vitro transformation. By using this approach, we report here on the identification of the Frizzled-ligand Norrin (Norrie disease protein) as a candidate tumour suppressor. Inhibition of Norrin expression promotes anchorage-independent growth, confers a strong growth advantage to cells and causes a reduction in p53 protein levels. Conversely, recombinant human Norrin increases p53 levels in a β-catenin dependent fashion. Interestingly, Norrin expression is stimulated by oncogenic H-RAS and BRAF, suggesting that Norrin is part of an early fail-safe mechanism to suppress transformation, and that mutation or down regulation of Norrin could contribute to tumour progression. Indeed, we found that Norrin expression is significantly decreased in melanoma, breast, prostate and ovarian cancer. These findings support the existence of a novel autocrine/paracrine feedback loop that constrains tumourigenesis, in which the crosstalk between the RAS and β-catenin pathways play an unanticipated role.

Objectives To investigate the effect of ACE inhibitors (ACEi) on the incidence of scleroderma renal crisis (SRC) when given prior to SRC in the prospectively collected cohort from the European Scleroderma Trial and Research Group (EUSTAR). Methods SSc patients without prior SRC and at least one follow-up visit were included and analyzed regarding SRC, arterial hypertension, and medication focusing on antihypertensive medication and glucocorticoids (GC). Results Out of 14,524 patients in the database, we identified 7648 patients with at least one follow-up. In 27,450 person-years (py), 102 patients developed SRC representing an incidence of 3.72 (3.06–4.51) per 1000 py. In a multivariable time-to-event analysis adjusted for age, sex, disease severity, and onset, 88 of 6521 patients developed SRC. The use of ACEi displayed an increased risk for the development of SRC with a hazard ratio (HR) of 2.55 (95% confidence interval (CI) 1.65–3.95). Adjusting for arterial hypertension resulted in a HR of 2.04 (95%CI 1.29–3.24). There was no evidence for an interaction of ACEi and arterial hypertension (HR 0.83, 95%CI 0.32–2.13, p  = 0.69). Calcium channel blockers (CCB), angiotensin receptor blockers (ARB), endothelin receptor antagonists, and GC—mostly in daily dosages below 15 mg of prednisolone—did not influence the hazard for SRC. Conclusions ACEi in SSc patients with concomitant arterial hypertension display an independent risk factor for the development of SRC but are still first choice in SRC treatment. ARBs might be a safe alternative, yet the overall safety of alternative antihypertensive drugs in SSc patients needs to be further studied.

ObjectiveTo determine whether joint synovitis and tendon friction rubs (TFRs) can predict the progression of systemic sclerosis (SSc) over time.Patients and methodsWe performed a prospective cohort study that included 1301 patients with SSc from the EUSTAR database with disease duration ≤3 years at inclusion and with a follow-up of at least 2 years. Presence or absence at clinical examination of synovitis and TFRs was extracted at baseline. Outcomes were skin, cardiovascular, renal and lung progression. Overall disease progression was defined according to the occurrence of at least one organ progression.ResultsJoint synovitis (HR: 1.26, 95% CI 1.01 to 1.59) and TFRs (HR: 1.32, 95% CI 1.03 to 1.70) were independently predictive of overall disease progression, as were also the diffuse cutaneous subset (HR: 1.30, 95% CI 1.05 to 1.61) and positive antitopoisomerase-I antibodies (HR: 1.25, 95% CI 1.02 to 1.53). Regarding skin progression, joint synovitis (HR: 1.67, 95% CI 1.06 to 2.64) and TFRs (HR: 1.69, 95% CI 1.02 to 2.77) were also independently predictive of worsening of the modified Rodnan skin score. For cardiovascular progression, joint synovitis was predictive of the occurrence of new digital ulcer(s) (HR: 1.45, 95% CI 1.08 to 1.96) and decreased left ventricular ejection fraction (HR: 2.20, 95% CI 1.06 to 4.57); TFRs were confirmed to be an independent predictor of scleroderma renal crisis (HR: 2.33, 95% CI 1.03 to 6.19).ConclusionsJoint synovitis and TFRs are independent predictive factors for disease progression in patients with early SSc. These easily detected clinical markers may be useful for the risk stratification of patients with SSc.

To identify predictive parameters for the progression of skin fibrosis within 1 year in patients with diffuse cutaneous SSc (dcSSc). An observational study using the EUSTAR database was performed. Inclusion criteria were dcSSc, American College of Rheumatology (ACR) criteria fulfilled, modified Rodnan skin score (MRSS) ≥7 at baseline visit, valid data for MRSS at 2nd visit, and available follow-up of 12±2 months. Worsening of skin fibrosis was defined as increase in MRSS >5 points and ≥25% from baseline to 2nd visit. In the univariate analysis, patients with progressive fibrosis were compared with non-progressors, and predictive markers with p<0.2 were included in the logistic regression analysis. The prediction models were then validated in a second cohort. A total of 637 dcSSc patients were eligible. Univariate analyses identified joint synovitis, short disease duration (≤15 months), short disease duration in females/patients without creatine kinase (CK) elevation, low baseline MRSS (≤22/51), and absence of oesophageal symptoms as potential predictors for progressive skin fibrosis. In the multivariate analysis, by employing combinations of the predictors, 17 models with varying prediction success were generated, allowing cohort enrichment from 9.7% progressive patients in the whole cohort to 44.4% in the optimised enrichment cohort. Using a second validation cohort of 188 dcSSc patients, short disease duration, low baseline MRSS and joint synovitis were confirmed as independent predictors of progressive skin fibrosis within 1 year resulting in a 4.5-fold increased prediction success rate. Our study provides novel, evidence-based criteria for the enrichment of dcSSc cohorts with patients who experience worsening of skin fibrosis which allows improved clinical trial design.

ObjectivesIn agreement with other autoimmune diseases, systemic sclerosis (SSc) is associated with a strong sex bias. However, unlike lupus, the effects of sex on disease phenotype and prognosis are poorly known. Therefore, we aimed to determine sex effects on outcomes.MethodWe performed a prospective observational study using the latest 2013 data extract from the EULAR scleroderma trials and research (EUSTAR) cohort. We looked at (i) sex influence on disease characteristics at baseline and (ii) then focused on patients with at least 2 years of follow-up to estimate the effects of sex on disease progression and survival.Results9182 patients with SSc were available (1321 men) for the baseline analyses. In multivariate analysis, male sex was independently associated with a higher risk of diffuse cutaneous subtype (OR: 1.68, (1.45 to 1.94); p<0.001), a higher frequency of digital ulcers (OR: 1.28 (1.11 to 1.47); p<0.001) and pulmonary hypertension (OR: 3.01 (1.47 to 6.20); p<0.003). In the longitudinal analysis (n=4499), after a mean follow-up of 4.9 (±2.7) years, male sex was predictive of new onset of pulmonary hypertension (HR: 2.66 (1.32 to 5.36); p=0.006) and heart failure (HR: 2.22 (1.06 to 4.63); p=0.035). 908 deaths were recorded, male sex predicted deaths of all origins (HR: 1.48 (1.19 to 1.84); p<0.001), but did not significantly account for SSc-related deaths.ConclusionsAlthough more common in women, SSc appears as strikingly more severe in men. Our results obtained through the largest worldwide database demonstrate a higher risk of severe cardiovascular involvement in men. These results raise the point of including sex in the management and the decision-making process.