Reversal of MYB-dependent suppression of MAFB expression overrides leukaemia phenotype in MLL-rearranged AML

The transcription factor MYB plays a pivotal role in haematopoietic homoeostasis and its aberrant expression is involved in the genesis and maintenance of acute myeloid leukaemia (AML). We have previously demonstrated that not all AML subtypes display the same dependency on MYB expression and that such variability is dictated by the nature of the driver mutation. However, whether this difference in MYB dependency is a general trend in AML remains to be further elucidated. Here, we investigate the role of MYB in human leukaemia by performing siRNA-mediated knock-down in cell line models of AML with different driver lesions. We show that the characteristic reduction in proliferation and the concomitant induction of myeloid differentiation that is observed in MLL-rearranged and t(8;21) leukaemias upon MYB suppression is not seen in AML cells with a complex karyotype. Transcriptome analyses revealed that MYB ablation produces consensual increase of MAFB expression in MYB-dependent cells and, interestingly, the ectopic expression of MAFB could phenocopy the effect of MYB suppression. Accordingly, in silico stratification analyses of molecular data from AML patients revealed a reciprocal relationship between MYB and MAFB expression, highlighting a novel biological interconnection between these two factors in AML and supporting new rationales of MAFB targeting in MLL-rearranged leukaemias.

Dissection of DLBCL microenvironment provides a gene expression-based predictor of survival applicable to formalin-fixed paraffin-embedded tissue

Background

Gene expression profiling (GEP) studies recognized a prognostic role for tumor microenvironment (TME) in diffuse large B-cell lymphoma (DLBCL), but the routinely adoption of prognostic stromal signatures remains limited.

Patients and methods

Here, we applied the computational method CIBERSORT to generate a 1028-gene matrix incorporating signatures of 17 immune and stromal cytotypes. Then, we carried out a deconvolution on publicly available GEP data of 482 untreated DLBCLs to reveal associations between clinical outcomes and proportions of putative tumor-infiltrating cell types. Forty-five genes related to peculiar prognostic cytotypes were selected and their expression digitally quantified by NanoString technology on a validation set of 175 formalin-fixed, paraffin-embedded DLBCLs from two randomized trials. Data from an unsupervised clustering analysis were used to build a model of clustering assignment, whose prognostic value was also assessed on an independent cohort of 40 cases. All tissue samples consisted of pretreatment biopsies of advanced-stage DLBCLs treated by comparable R-CHOP/R-CHOP-like regimens.

Results

In silico analysis demonstrated that higher proportion of myofibroblasts (MFs), dendritic cells, and CD4⁺ T cells correlated with better outcomes and the expression of genes in our panel is associated with a risk of overall and progression-free survival. In a multivariate Cox model, the microenvironment genes retained high prognostic performance independently of the cell-of-origin (COO), and integration of the two prognosticators (COO + TME) improved survival prediction in both validation set and independent cohort. Moreover, the major contribution of MF-related genes to the panel and Gene Set Enrichment Analysis suggested a strong influence of extracellular matrix determinants in DLBCL biology.

Conclusions

Our study identified new prognostic categories of DLBCL, providing an easy-to-apply gene panel that powerfully predicts patients’ survival. Moreover, owing to its relationship with specific stromal and immune components, the panel may acquire a predictive relevance in clinical trials exploring new drugs with known impact on TME.

u-PAR expression in cancer associated fibroblast: new acquisitions in multiple myeloma progression

Background

Multiple Myeloma (MM) is a B-cell malignancy in which clonal plasma cells progressively expand within the bone marrow (BM) as effect of complex interactions with extracellular matrix and a number of microenvironmental cells. Among these, cancer-associated fibroblasts (CAF) mediate crucial reciprocal signals with MM cells and are associated to aggressive disease and poor prognosis. A large body of evidence emphasizes the role of the urokinase plasminogen activator (u-PA) and its receptor u-PAR in potentiating the invasion capacity of tumor plasma cells, but little is known about their role in the biology of MM CAF. In this study, we investigated the u-PA/u-PAR axis in MM-associated fibroblasts and explore additional mechanisms of tumor/stroma interplay in MM progression.

Methods

CAF were purified from total BM stromal fraction of 64 patients including monoclonal gammopathy of undetermined significance, asymptomatic and symptomatic MM, as well as MM in post-treatment remission. Flow cytometry, Real Time PCR and immunofluorescence were performed to investigate the u-PA/u-PAR system in relation to the level of activation of CAF at different stages of the disease. Moreover, proliferation and invasion assays coupled with silencing experiments were used to prove, at functional level, the function of u-PAR in CAF.

Results

We found higher activation level, along with increased expression of pro-invasive molecules, including u-PA, u-PAR and metalloproteinases, in CAF from patients with symptomatic MM compared to the others stages of the disease. Consistently, CAF from active MM as well as U266 cell line under the influence of medium conditioned by active MM CAF, display higher proliferative rate and invasion potential, which were significantly restrained by u-PAR gene expression inhibition.

Conclusions

Our data suggest that the stimulation of u-PA/u-PAR system contributes to the activated phenotype and function of CAF during MM progression, providing a biological rationale for future targeted therapies against MM.

Experience with a bone anchor sling for treating female stress urinary incontinence: outcome at 30 months

OBJECTIVES

To evaluate the clinical and video-urodynamic outcome in women with by stress urinary incontinence (SUI) treated with a bone-anchored pubovaginal sling.

PATIENTS AND METHODS

The study included 70 women with SUI (as evaluated by a clinical examination, a voiding questionnaire, a short pad-test and video-urodynamics) who had a bone-anchor sling procedure, with or without cystocele repair, from January 1999 to December 2001; they were re-evaluated after a long-term follow-up (mean 30 months).

RESULTS

The long-term outcome showed a success rate of > 95%; the clinical and video-urodynamic findings showed good functional and anatomical results, and an improvement in voiding performance in most patients. There was a low incidence of complications during and after surgery (2.8%).

CONCLUSIONS

This approach gives, in highly selected patients, a high success rate and low incidence of complications. The technique is easy to learn and the costs to the financing bodies and public healthcare are low, making it a candidate for an alternative procedure to the standard techniques for SUI.

The potential of near-infrared reflectance spectroscopy for soil analysis — a case study from the Riverine Plain of south-eastern Australia

Environmental management in agricultural systems must be maintained while controlling costs and increasing productivity. To obtain a better response from inputs in agriculture, cost-effective soil analysis is needed to enable site-specific applications. Near-infrared reflectance spectroscopy (NIRS) technology has the potential to provide a rapid, low-cost analysis enabling within field variability to be identified. NIRS was evaluated for its ability to predict a range of soil properties in the Riverine Plain soils of southern New South Wales. Over 550 topsoil (0-10�cm) and 300 subsoil (40-50 cm) samples from a range of soil types were air dried and ground before scanning with a NIRSystems model 6500 scanning spectrophotometer. The Partial Least Squares (PLS) regression procedure was used to determine the best correlation (i.e. calibration) between the chemical reference data and spectral data for both topsoil and subsoil samples. A validation set of samples was used to test the predictive ability of NIRS for a number of soil properties. The results demonstrated that NIRS can successfully determine some soil properties in both the topsoil and subsoil. In the topsoil, cation exchange capacity (CEC), exchangeable Ca and Mg, pH and Ca : Mg ratio were predicted with a high level of accuracy and organic carbon and exchangeable sodium percentage (ESP) with an acceptable level of accuracy. In the subsoil, CEC, exchangeable Na, Ca, Mg, ESP, pH and Ca : Mg ratio were all predicted with a high degree of accuracy. The predictive ability of NIRS for many soil constituents may make it suitable for use in agricultural soil assessment for site-specific agriculture in the Riverine Plain soils of southern New South Wales.