Cis-by-Trans Regulatory Divergence Causes the Asymmetric Lethal Effects of an Ancestral Hybrid Incompatibility Gene

The Dobzhansky and Muller (D-M) model explains the evolution of hybrid incompatibility (HI) through the interaction between lineage-specific derived alleles at two or more loci. In agreement with the expectation that HI results from functional divergence, many protein-coding genes that contribute to incompatibilities between species show signatures of adaptive evolution, including Lhr, which encodes a heterochromatin protein whose amino acid sequence has diverged extensively between Drosophila melanogaster and D. simulans by natural selection. The lethality of D. melanogaster/D. simulans F1 hybrid sons is rescued by removing D. simulans Lhr, but not D. melanogaster Lhr, suggesting that the lethal effect results from adaptive evolution in the D. simulans lineage. It has been proposed that adaptive protein divergence in Lhr reflects antagonistic coevolution with species-specific heterochromatin sequences and that defects in LHR protein localization cause hybrid lethality. Here we present surprising results that are inconsistent with this coding-sequence-based model. Using Lhr transgenes expressed under native conditions, we find no evidence that LHR localization differs between D. melanogaster and D. simulans, nor do we find evidence that it mislocalizes in their interspecific hybrids. Rather, we demonstrate that Lhr orthologs are differentially expressed in the hybrid background, with the levels of D. simulans Lhr double that of D. melanogaster Lhr. We further show that this asymmetric expression is caused by cis-by-trans regulatory divergence of Lhr. Therefore, the non-equivalent hybrid lethal effects of Lhr orthologs can be explained by asymmetric expression of a molecular function that is shared by both orthologs and thus was presumably inherited from the ancestral allele of Lhr. We present a model whereby hybrid lethality occurs by the interaction between evolutionarily ancestral and derived alleles

Elevated levels of soluble CD44 are associated with advanced disease and in vitro proliferation of neoplastic lymphocytes in B-cell chronic lymphocytic leukaemia

PURPOSE: Increased expression of the adhesion molecule CD44 has been associated with an unfavourable clinical outcome in lymphomas. We evaluated the prognostic value of soluble CD44 in B-cell chronic lymphocytic leukaemia (B-CLL) and analysed the source and regulation of CD44 secretion in B-CLL clones in vitro. PATIENTS AND METHODS: Levels of soluble CD44 standard (sCD44s) and of the soluble variant isoform CD44v6 (sCD44v6) were analysed by enzyme linked immuno sorbent assay. Highly purified B-CLL cells (98% CD19 + CD3 - cells) were stimulated in vitro by different combinations of thioredoxin (Trx), Staphylococcus aureus Cowan strain 1 (SAC), IL-2, IL-4, IL-10, 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and by anti-CD40 mAbs presented on irradiated CD32L cells. RESULTS: Serum levels of sCD44s and of sCD44v6 are significantly elevated in B-CLL patients (n = 90) in comparison with normal persons (n = 44) (P > 0.001). Elevated levels of sCD44s and sCD44v6 are associated with an advanced disease as reflected by an extended lymph node involvement (P > 0.02), an advanced Binet (P > 0.03) and Rai stage (P > 0.04) and chemotherapy requirement (P > 0.02). High levels of sCD44s are associated with high leukocyte counts (P > 0.04) and increased sCD44v6 is significantly associated with splenomegaly (P > 0.002). In B-CLL sCD44s as well as sCD44v6 is shed from leukaemia cells as shown by in vitro cultures. Stimulation of B-CLL clones results in a proliferation-associated increased secretion of sCD44s (rho = 0.7; P = 0.0001) and of sCD44v6 (rho = 0.5; P = 0.005). B-CLL clones from advanced stage patients are characterised by an increased capacity for proliferation and CD44 production in comparison with early stage patients. CONCLUSIONS: Both sCD44s and sCD44v6 represent a reliable prognostic marker in B-CLL and may be involved in the pathogenesis of B-CLL

How We Treat Localized Rectal Cancer—An Institutional Paradigm for Total Neoadjuvant Therapy

Total neoadjuvant therapy (TNT)—the neoadjuvant employment of radiotherapy (RT) or chemoradiation (CRT) as well as chemotherapy (CHT) before surgery—may lead to increased pathological complete response (pCR) rates as well as a reduction in the risk of distant metastases in locally advanced rectal cancer. Furthermore, increased response rates may allow organ-sparing strategies in a growing number of patients with low rectal cancer and upfront immunotherapy has shown very promising early results in patients with microsatellite instability (MSI)-high/mismatch-repair-deficient (dMMR) tumors. Despite the lack of a generally accepted treatment standard, we strongly believe that existing data is sufficient to adopt the concept of TNT and immunotherapy in clinical practice. The treatment algorithm presented in the following is based on our interpretation of the current data and should serve as a practical guide for treating physicians—without any claim to general validity

Nilotinib as frontline and second-line therapy in chronic myeloid leukemia: open questions

Nilotinib is a second generation ABL tyrosine kinase inhibitor (TKI) that exerts major anti-leukemic effects in newly diagnosed patients with chronic myeloid leukemia (CML) as well as in most patients with imatinib-resistant CML. In freshly diagnosed patients, the anti-leukemic activity of nilotinib exceeds the efficacy of imatinib, and although long-term data for nilotinib are not available yet, the drug has recently been approved for firstline treatment of chronic phase CML in various countries. Still however, several questions concerning the optimal dose, follow-up parameters, long-term safety, and patient selection remain open. Likewise, it remains uncertain whether both Sokal low-risk and high-risk patients should receive nilotinib as frontline therapy in the future. Another question is whether nilotinib can completely eradicate CML in a subset of patients. Furthermore, it remains unclear whether and what comorbidity must be regarded as relative or absolute contra-indication for this TKI. To discuss these issues, the Austrian CML Working Group organized a series of meetings in 2010. In the current article, the outcomes from these discussions are summarized and presented together with recommendations for frontline use of TKIs in various groups of patients with CML. These recommendations should assist in daily practice as well as in the preparation and conduct of clinical trials

Committee of the European Association of Cardiovascular Imaging Association

(EACVI

DISSEMINATED FUSARIOSIS IN IMMUNOCOMPROMISED CHILDREN-ANALYSIS OF RECENT CASES IDENTIFIED IN THE GLOBAL FUNGISCOPE REGISTRY

Disseminated fusariosis is a rare disease, and data are scant in pediatric patients. In the FungiScope registry, we identified 10 children with disseminated fusariosis between 2006 and 2015. Our analysis of the largest pediatric case series reported to date adds pediatric-specific experience to the management of this opportunistic infection in children

Disseminated Fusariosis in Immunocompromised Children-Analysis of Recent Cases Identified in the Global Fungiscope Registry

Disseminated fusariosis is a rare disease, and data are scant in pediatric patients. In the FungiScope registry, we identified 10 children with disseminated fusariosis between 2006 and 2015. Our analysis of the largest pediatric case series reported to date adds pediatric-specific experience to the management of this opportunistic infection in children