Geldanamycin and its derivatives as Hsp90 inhibitors

The Hsp90 molecule, one of the most abundant heat shock proteins in mammalian cells, maintains homeostasis and prevents stress-induced cellular damage. Hsp90 is expressed under normal conditions at a level of about 1-2 Percent of total proteins, while its expression increases 2-10 fold in cancer cells. The two main constitutively expressed isoforms of Hsp90 are known as Hsp90-alpha and Hsp90-beta, and their upregulation is associated with tumor progression, invasion and formation of metastases, as well as development of drug resistance. The Hsp90 is a key target for many newly established, potent anticancer agents containing Hsp90 N-terminal ATP binding inhibitors, such as geldanamycin, and its analogues 17AAG and 17DMAG. The therapeutic usage of geldanamycin has been limited due to its poor water solubility and severe hepatotoxicity. Therefore, its analogues, including 17AAG, 17DMAG, Tanespimycin and Retaspimycin hydrochloride, with improved pharmacokinetic profiles, have been developed

Molecular basis for the bifunctional Uba4-Urm1 sulfur-relay system in tRNA thiolation and ubiquitin-like conjugation.

The chemical modification of tRNA bases by sulfur is crucial to tune translation and to optimize protein synthesis. In eukaryotes, the ubiquitin-related modifier 1 (Urm1) pathway is responsible for the synthesis of 2-thiolated wobble uridine (U34 ). During the key step of the modification cascade, the E1-like activating enzyme ubiquitin-like protein activator 4 (Uba4) first adenylates and thiocarboxylates the C-terminus of its substrate Urm1. Subsequently, activated thiocarboxylated Urm1 (Urm1-COSH) can serve as a sulfur donor for specific tRNA thiolases or participate in ubiquitin-like conjugation reactions. Structural and mechanistic details of Uba4 and Urm1 have remained elusive but are key to understand the evolutionary branch point between ubiquitin-like proteins (UBL) and sulfur-relay systems. Here, we report the crystal structures of full-length Uba4 and its heterodimeric complex with its substrate Urm1. We show how the two domains of Uba4 orchestrate recognition, binding, and thiocarboxylation of the C-terminus of Urm1. Finally, we uncover how the catalytic domains of Uba4 communicate efficiently during the reaction cycle and identify a mechanism that enables Uba4 to protect itself against self-conjugation with its own product, namely activated Urm1-COSH

Geldanamycin-induced osteosarcoma cell death is associated with hyperacetylation and loss of mitochondrial pool of heat shock protein 60 (hsp60)

Osteosarcoma is one of the most malignant tumors of childhood and adolescence that is often resistant to standard chemo- and radio-therapy. Geldanamycin and geldanamycin analogs have been recently studied as potential anticancer agents for osteosarcoma treatment. Here, for the first time, we have presented novel anticancer mechanisms of geldanamycin biological activity. Moreover, we demonstrated an association between the effects of geldanamycin on the major heat shock proteins (HSPs) and the overall survival of highly metastatic human osteosarcoma 143B cells. We demonstrated that the treatment of 143B cells with geldanamycin caused a subsequent upregulation of cytoplasmic Hsp90 and Hsp70 whose activity is at least partly responsible for cancer development and drug resistance. On the other hand, geldanamycin induced upregulation of Hsp60 gene expression, and a simultaneous loss of hyperacetylated Hsp60 mitochondrial protein pool resulting in decreased viability and augmented cancer cell death. Hyperacetylation of Hsp60 seems to be associated with anticancer activity of geldanamycin. In light of the fact that mitochondrial dysfunction plays a critical role in the apoptotic signaling pathway, the presented data may support a hypothesis that Hsp60 can be another functional part of mitochondria-related acetylome being a potential target for developing novel anticancer strategies

Car drivers' road safety performance. A benchmark across 32 countries

The road safety performance of a country and the success of policy measures can be measured and monitored in different ways. In addition to the traditional road safety indicators based on the number of fatalities or injured people in road traffic crashes, complementary road safety performance indicators can be used in relation to vehicles, infrastructure, or road users' behaviour. The last-mentioned can be based on data from roadside surveys or from questionnaire surveys. However, results of such surveys are seldom comparable across countries due to differences in aims, scope, or methodology. This paper is based on the second edition of the E-Survey of Road Users' Attitudes (ESRA), an online survey carried out in 2018, and includes data from more than 35,000 road users across 32 countries. The objective is to present the main results of the ESRA survey regarding the four most important risky driving behaviours in traffic: driving under the influence (alcohol/drugs), speeding, mobile phone use while driving, and fatigued driving. The paper explores several aspects related to these behaviours as car driver, such as the self-declared behaviours, acceptability and risk perception, support for policy measures, and opinions on traffic rules and penalties. Results show that despite the high perception of risk and low acceptability of all the risky driving behaviours analysed, there is still a high percentage of car drivers who engage in risky behaviours in traffic in all the regions analysed. Speeding and the use of a mobile phone while driving were the most frequent self-declared behaviours. On the other hand, driving under the influence of alcohol or drugs was the least declared behaviour. Most respondents support policy measures to restrict risky behaviour in traffic and believe that traffic rules are not being checked regularly enough, and should be stricter. The ESRA survey proved to be a valuable source of information to understand the causes underlying road traffic crashes. It offers a unique database and provides policy makers and researchers with valuable insights into public perception of road safety

The spontaneous course of human herpesvirus 6 DNA-associated myocarditis and the effect of immunosuppressive intervention

INTRODUCTION: This study investigated the spontaneous clinical course of patients with endomyocardial biopsy (EMB)-proven lymphocytic myocarditis and cardiac human herpesvirus 6 (HHV6) DNA presence, and the effectiveness of steroid-based intervention in HHV6-positive patients. RESULTS: 756 heart failure (HF) patients underwent an EMB procedure to determine the underlying cause of unexplained HF. Low levels of HHV6 DNA, detectable by nested PCR only, were found in 10.4% of the cases (n = 79) of which 62% (n = 49) showed myocardial inflammation. The spontaneous course of patients with EMB-proven HHV6 DNA-associated lymphocytic myocarditis (n = 26) showed significant improvements in the left ventricular ejection fraction (LVEF) and clinical symptoms, respectively, in 15/26 (60%) patients, 3–12 months after disease onset. EMB mRNA expression of components of the NLRP3 inflammasome pathway and protein analysis of cardiac remodeling markers, analyzed by real-time PCR and MALDI mass spectrometry, respectively, did not differ between HHV6-positive and -negative patients. In another cohort of patients with ongoing symptoms related to lymphocytic myocarditis associated with cardiac levels of HHV6-DNA copy numbers <500 copies/µg cardiac DNA, quantified by real-time PCR, the efficacy and safety of steroid-based immunosuppression for six months was investigated. Steroid-based immunosuppression improved the LVEF (≥5%) in 8/10 patients and reduced cardiac inflammation in 7/10 patients, without an increase in cardiac HHV6 DNA levels in follow-up EMBs. CONCLUSION: Low HHV6 DNA levels are frequently detected in the myocardium, independent of inflammation. In patients with lymphocytic myocarditis with low levels of HHV6 DNA, the spontaneous clinical improvement is nearby 60%. In selected symptomatic patients with cardiac HHV6 DNA copy numbers less than 500 copies/µg cardiac DNA and without signs of an active systemic HHV6 infection, steroid-based therapy was found to be effective and safe. This finding needs to be further confirmed in large, randomized trials

Phenotyping heart failure patients for iron deficiency and use of intravenous iron therapy: data from the Swedish Heart Failure Registry.

AIMS: Iron deficiency (ID) is associated with poor prognosis regardless of anaemia. Intravenous iron improves quality of life and outcomes in patients with ID and heart failure (HF) with reduced ejection fraction (HFrEF). In the Swedish HF registry, we assessed (i) frequency and predictors of ID testing; (ii) prevalence and outcomes of ID with/without anaemia; (iii) use of ferric carboxymaltose (FCM) and its predictors in patients with ID. METHODS AND RESULTS: We used multivariable logistic regressions to assess patient characteristics independently associated with ID testing/FCM use, and Cox regressions to assess risk of outcomes associated with ID. Of 21 496 patients with HF and any ejection fraction enrolled in 2017-2018, ID testing was performed in 27%. Of these, 49% had ID and more specifically 36% had ID-/anaemia-, 15% ID-/anaemia+, 29% ID+/anaemia-, and 20% ID+/anaemia+ (48%, 39%, 13%, 30% and 18% in HFrEF, respectively). Risk of recurrent all-cause hospitalizations was higher in patients with ID regardless of anaemia. Of 1959 patients with ID, 19% received FCM (24% in HFrEF). Important independent predictors of ID testing and FCM use were anaemia, higher New York Heart Association class, having HFrEF, and referral to HF specialty care. CONCLUSION: In this nationwide HF registry, ID testing occurred in only about a quarter of the patients. Among tested patients, ID was present in one half, but only one in five patients received FCM indicating low adherence to current guidelines on screening and treatment

Buffering effects of soil seed banks on plant community composition in response to land use and climate

Aim Climate and land use are key determinants of biodiversity, with past and ongoing changes posing serious threats to global ecosystems. Unlike most other organism groups, plant species can possess dormant life‐history stages such as soil seed banks, which may help plant communities to resist or at least postpone the detrimental impact of global changes. This study investigates the potential for soil seed banks to achieve this. Location Europe. Time period 1978–2014. Major taxa studied Flowering plants. Methods Using a space‐for‐time/warming approach, we study plant species richness and composition in the herb layer and the soil seed bank in 2,796 community plots from 54 datasets in managed grasslands, forests and intermediate, successional habitats across a climate gradient. Results Soil seed banks held more species than the herb layer, being compositionally similar across habitats. Species richness was lower in forests and successional habitats compared to grasslands, with annual temperature range more important than mean annual temperature for determining richness. Climate and land‐use effects were generally less pronounced when plant community richness included seed bank species richness, while there was no clear effect of land use and climate on compositional similarity between the seed bank and the herb layer. Main conclusions High seed bank diversity and compositional similarity between the herb layer and seed bank plant communities may provide a potentially important functional buffer against the impact of ongoing environmental changes on plant communities. This capacity could, however, be threatened by climate warming. Dormant life‐history stages can therefore be important sources of diversity in changing environments, potentially underpinning already observed time‐lags in plant community responses to global change. However, as soil seed banks themselves appear, albeit less, vulnerable to the same changes, their potential to buffer change can only be temporary, and major community shifts may still be expected

Health status improvement with ferric carboxymaltose in heart failure with reduced ejection fraction and iron deficiency.

AIM: Intravenous ferric carboxymaltose (FCM) has been shown to improve overall quality of life in iron-deficient heart failure with reduced ejection fraction (HFrEF) patients at a trial population level. This FAIR-HF and CONFIRM-HF pooled analysis explored the likelihood of individual improvement or deterioration in Kansas City Cardiomyopathy Questionnaire (KCCQ) domains with FCM versus placebo and evaluated the stability of this response over time. METHODS AND RESULTS: Changes versus baseline in KCCQ overall summary score (OSS), clinical summary score (CSS) and total symptom score (TSS) were assessed at weeks 12 and 24 in FCM and placebo groups. Mean between-group differences were estimated and individual responder analyses and analyses of response stability were performed. Overall, 760 (FCM, n = 454) patients were studied. At week 12, the mean improvement in KCCQ OSS was 10.6 points with FCM versus 4.8 points with placebo (least-square mean difference [95% confidence interval, CI] 4.36 [2.14; 6.59] points). A higher proportion of patients on FCM versus placebo experienced a KCCQ OSS improvement of ≥5 (58.3% vs. 43.5%; odds ratio [95% CI] 1.81 [1.30; 2.51]), ≥10 (42.4% vs. 29.3%; 1.73 [1.23; 2.43]) or ≥15 (32.1% vs. 22.6%; 1.46 [1.02; 2.11]) points. Differences were similar at week 24 and for CSS and TSS domains. Of FCM patients with a ≥5-, ≥10- or ≥15-point improvement in KCCQ OSS at week 12, >75% sustained this improvement at week 24. CONCLUSION: Treatment of iron-deficient HFrEF patients with intravenous FCM conveyed clinically relevant improvements in health status at an individual-patient level; benefits were sustained over time in most patients

Responder analysis for improvement in 6-min walk test with ferric carboxymaltose in patients with heart failure with reduced ejection fraction and iron deficiency

Aim Improving functional capacity is a key goal in heart failure (HF). This pooled analysis of FAIR-HF and CONFIRM-HF assessed the likelihood of improvement or deterioration in 6-min walk test (6MWT) among iron-deficient patients with chronic HF with reduced ejection fraction (HFrEF) receiving ferric carboxymaltose (FCM). Methods and results Data for 760 patients (FCM: n = 454; placebo: n = 306) were analysed. The proportions of patients receiving FCM or placebo who had ≥20, ≥30, and ≥40 m improvements or ≥10 m deterioration in 6MWT at 12 and 24 weeks were assessed. Patients receiving FCM experienced a mean (standard deviation) 31.1 (62.3) m improvement in 6MWT versus 0.1 (77.1) m improvement for placebo at week 12 (difference in mean changes 26.8 [16.6;37.0]). At week 12, the odds [95% confidence interval] of 6MWT improvements of ≥20 m (odds ratio 2.16 [1.57–2.96]; p < 0.0001), ≥30 m (2.00 [1.44–2.78]; p < 0.0001), and ≥40 m (2.29 [1.60–3.27]; p < 0.0001) were greater with FCM versus placebo, while the odds of a deterioration ≥10 m were reduced with FCM versus placebo (0.55 [0.38–0.80]; p = 0.0019). Among patients who experienced 6MWT improvements of ≥20, ≥30, or ≥40 m with FCM at week 12, more than 80% sustained this improvement at week 24. Conclusion Ferric carboxymaltose resulted in a significantly higher likelihood of improvement and a reduced likelihood of deterioration in 6MWT versus placebo among iron-deficient patients with HF. Of the patients experiencing clinically significant improvements at week 12, the majority sustained this improvement at week 24. These results are supportive of FCM to improve exercise capacity in HF

MGMT promoter hypermethylation and K-RAS, PTEN and TP53 mutations in tamoxifen-exposed and non-exposed endometrial cancer cases

background: Tamoxifen has anti-oestrogenic and anti-tumour activity in the breast, but is oestrogenic and carcinogenic in the endometrium. It can induce experimental tumours by both hormonal and DNA-damaging mechanisms, but its carcinogenic mode of action in human endometrium remains unclear. methods: We investigated whether an epigenetic mechanism, involving promoter hypermethylation of the gene for the DNA repair enzyme MGMT (O6-methylguanine DNA methyltransferase), was associated with K-RAS, TP53 and PTEN mutations in endometrial tumours from women treated with tamoxifen (TAM, n=30) or unexposed to the drug (EC, n=38). results: There were significant (PA, occurred in small numbers in both groups. TP53 mutations were of mainly A>G, C>T and indel modifications in both groups, but more frequent in TAM cases. PTEN mutations dominated in EC tumours and were of the type that has large impact on protein function, such as indel or nonsense mutations. These observations alongside the mutational spectrum in PTEN suggest that the malignancies arise from different backgrounds, hence pointing to an effect of tamoxifen. Both groups displayed MGMT promoter hypermethylation. This coincided with mutations more frequently in the TAM (78%) than in the EC (50%) group, even though there were significantly (P<0.05) fewer mutations and methylations in TAM cases. conclusions: Although the difference in coincidence did not reach significance with the current sample size, the findings suggest that epigenetic processes may play a role in the way tamoxifen induces endometrial cancer