Combined proteomics and CRISPR‒Cas9 screens in PDX identify ADAM10 as essential for leukemia in vivo

BACKGROUND

Acute leukemias represent deadly malignancies that require better treatment. As a challenge, treatment is counteracted by a microenvironment protecting dormant leukemia stem cells.

METHODS

To identify responsible surface proteins, we performed deep proteome profiling on minute numbers of dormant patient-derived xenograft (PDX) leukemia stem cells isolated from mice. Candidates were functionally screened by establishing a comprehensive CRISPR‒Cas9 pipeline in PDX models in vivo.

RESULTS

A disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) was identified as an essential vulnerability required for the survival and growth of different types of acute leukemias in vivo, and reconstitution assays in PDX models confirmed the relevance of its sheddase activity. Of translational importance, molecular or pharmacological targeting of ADAM10 reduced PDX leukemia burden, cell homing to the murine bone marrow and stem cell frequency, and increased leukemia response to conventional chemotherapy in vivo.

CONCLUSIONS

These findings identify ADAM10 as an attractive therapeutic target for the future treatment of acute leukemias.

Cardiovascular rehabilitation delivery and outcomes in Switzerland: data from a national database over the last decade

Background

Cardiac rehabilitation (CR) is a multidisciplinary, comprehensive, exercise-based intervention strongly recommended by current guidelines to improve symptoms and quality of life and to reduce cardiovascular adverse outcomes, mainly in patients with coronary artery disease and heart failure. CR activities have not been reported on a Swiss national base so far.

Purpose

To report CR outcome variables from a Swiss national base.

Methods

As part of the Swiss working group for cardiovascular prevention, rehabilitation, and sports cardiology (SCPRS) quality standards, all Swiss CR centres provide yearly a quality indicator report on an online questionnaire. Annual data from 2010 to 2019 were transferred as medians or means of all individual patients' data from each centre. We used the t-Student test to compare changes of outcome variables between entry and exit of the programme.

Results

A total of 133,060 CR patients were included (68,690 inpatients and 64,370 outpatients) with a progressive increase reaching its climax with 14'909 patients/year in 2018. Mean age ± standard deviation (SD) in outpatient and inpatient programmes was 60±1 and 68±1 years, and women percentage 21% and 32%, respectively. The most common CR indication was acute coronary syndrome (51%) in outpatient, whereas cardiovascular surgery of various types (60%) was the main indication in inpatient programmes. Mean improvement ± SD of functional capacity was 38% ±3.6 using the six-minute walk test in inpatient (p<0.001) and 21% ±2 using cycle-ergometer maximal exercise testing in outpatient programmes (p<0.001). Quality of life mainly assessed with the 12-item Short Form Survey (SF-12) in outpatient CR improved by 13% ±4.5. MacNew Heart questionnaire systematically performed in inpatient programmes showed significant improvement at emotional level by 12% ±0.4, at physical level by 30% ±0.9, and at social level by 18% ±0.6.

Conclusion

Even if still underutilised in certain groups of patients such as women or heart failure, CR has gained growing importance in Switzerland during the last decade. Functional capacity, as well as quality of life, was significantly improved. Individual CR patient data should be collected in the future to improve assessment of outcome parameters and benchmarking of centres.

Funding Acknowledgement

Type of funding sources: None.

[Suddenly occurring exercise intolerance]

In this case report, the differencial diagnosis of exercise intolerance associated with dyspnea and the diagnostic approach with cardio-pulmonary exercise testing with detection of an exercise induced second-degree atrio-ventricular block as a cause of chronotropic incompetence is described.

[Proposal for a shortened i.v. antibiotic treatment as cost-saving measure in the treatment of uncomplicated infections]

New oral antibiotics with high rates of absorption and good bioavailability make it possible to reduce costs by shortening the i.v. treatment period. During two 2-month periods we analyzed every patient of the Medical Department who received i.v. treatment. We tried to reduce i.v. treatment duration simply by discussion with the responsible physician, guided essentially by the clinical course. The number of patients with reduced i.v. treatment were compared with a control period. We found that by this means, an i.v. treatment period of 4-7 days could often be reduced to 1-3 days. The main target pathologies with corresponding cost savings appeared to be infections of the lower respiratory tract, with a cost-saving potential of 1.4 days (p < 0.0001) and urinary tract infections with a cost-saving potential of SFr. 179.-(US$ 138.-) per case.

Atmospheric reactions of polycyclic aromatic hydrocarbons: facile formation of mutagenic nitro derivatives

Directly active mutagens are formed on exposure of the promutagen benzo[a]pyrene to gaseous pollutants in smog. In simulated atmospheres containing 1 part per million nitrogen dioxide and traces of nitric acid, directly mutagenic nitro derivatives are readily formed from both benzo[a]pyrene and perylene, a non-mutagen in the Ames reversion assay. Possible formation of direct mutagens by such reactions on sample collection filters, in exhaust effluents, and in the atmosphere should be recognized.