Overexpression of wild-type IL-7Rα promotes T-cell acute lymphoblastic leukemia/lymphoma.

Tight regulation of IL-7Rα expression is essential for normal T-cell development. IL-7Rα gain-of-function mutations are known drivers of T-cell acute lymphoblastic leukemia (T-ALL). Although a subset of patients with T-ALL display high IL7R messenger RNA levels and cases with IL7R gains have been reported, the impact of IL-7Rα overexpression, rather than mutational activation, during leukemogenesis remains unclear. In this study, overexpressed IL-7Rα in tetracycline-inducible Il7r transgenic and Rosa26 IL7R knockin mice drove potential thymocyte self-renewal, and thymus hyperplasia related to increased proliferation of T-cell precursors, which subsequently infiltrated lymph nodes, spleen, and bone marrow, ultimately leading to fatal leukemia. The tumors mimicked key features of human T-ALL, including heterogeneity in immunophenotype and genetic subtype between cases, frequent hyperactivation of the PI3K/Akt pathway paralleled by downregulation of p27Kip1 and upregulation of Bcl-2, and gene expression signatures evidencing activation of JAK/STAT, PI3K/Akt/mTOR and Notch signaling. Notably, we also found that established tumors may no longer require high levels of IL-7R expression upon secondary transplantation and progressed in the absence of IL-7, but remain sensitive to inhibitors of IL-7R-mediated signaling ruxolitinib (Jak1), AZD1208 (Pim), dactolisib (PI3K/mTOR), palbociclib (Cdk4/6), and venetoclax (Bcl-2). The relevance of these findings for human disease are highlighted by the fact that samples from patients with T-ALL with high wild-type IL7R expression display a transcriptional signature resembling that of IL-7-stimulated pro-T cells and, critically, of IL7R-mutant cases of T-ALL. Overall, our study demonstrates that high expression of IL-7Rα can promote T-cell tumorigenesis, even in the absence of IL-7Rα mutational activation.

Pollen Proteases Play Multiple Roles in Allergic Disorders.

Allergic diseases are a major health concern worldwide. Pollens are important triggers for allergic rhinitis, conjunctivitis and asthma. Proteases released upon pollen grain hydration appear to play a major role in the typical immunological and inflammatory responses that occur in patients with allergic disorders. In this study, we aimed to identify specific proteolytic activity in a set of pollens with diverse allergenic potential. Diffusates from Chenopodium album, Plantago lanceolata and Eucalyptus globulus were added to a confluent monolayer of Calu-3 cells grown in an air-liquid interface system. We identified serine proteases and metalloproteinases in all pollen diffusates investigated. Proteases found in these pollen diffusates were shown to compromise the integrity of the lung epithelial barrier by disrupting transmembrane adhesion proteins E-cadherin, claudin-1 and Occludin, as well as, the cytosolic complex zonula occludens-1 (ZO-1) resulting in a time-dependent increase in transepithelial permeability. Tight junction disruption and increased transepithelial permeability facilitates allergen exposure to epithelial sub-layers contributing to the sensitization to a wide range of allergens. These pollen extracts also induced an increase in the release of interleukin 6 (IL-6) and interleukin 8 (IL-8) cytokines measured by flow cytometry possibly as a result of the activation of protease-activated receptors 2 (PAR-2).

Interleukin-7 receptor α mutational activation can initiate precursor B-cell acute lymphoblastic leukemia.

Interleukin-7 receptor α (encoded by IL7R) is essential for lymphoid development. Whether acute lymphoblastic leukemia (ALL)-related IL7R gain-of-function mutations can trigger leukemogenesis remains unclear. Here, we demonstrate that lymphoid-restricted mutant IL7R, expressed at physiological levels in conditional knock-in mice, establishes a pre-leukemic stage in which B-cell precursors display self-renewal ability, initiating leukemia resembling PAX5 P80R or Ph-like human B-ALL. Full transformation associates with transcriptional upregulation of oncogenes such as Myc or Bcl2, downregulation of tumor suppressors such as Ikzf1 or Arid2, and major IL-7R signaling upregulation (involving JAK/STAT5 and PI3K/mTOR), required for leukemia cell viability. Accordingly, maximal signaling drives full penetrance and early leukemia onset in homozygous IL7R mutant animals. Notably, we identify 2 transcriptional subgroups in mouse and human Ph-like ALL, and show that dactolisib and sphingosine-kinase inhibitors are potential treatment avenues for IL-7R-related cases. Our model, a resource to explore the pathophysiology and therapeutic vulnerabilities of B-ALL, demonstrates that IL7R can initiate this malignancy.

A Systematic Pan-Cancer Analysis of Genetic Heterogeneity Reveals Associations with Epigenetic Modifiers.

Intratumor genetic heterogeneity (ITH) is the main obstacle to effective cancer treatment and a major mechanism of drug resistance. It results from the continuous evolution of different clones of a tumor over time. However, the molecular features underlying the emergence of genetically-distinct subclonal cell populations remain elusive. Here, we conducted an exhaustive characterization of ITH across 2807 tumor samples from 16 cancer types. Integration of ITH scores and somatic variants detected in each tumor sample revealed that mutations in epigenetic modifier genes are associated with higher ITH levels. In particular, genes that regulate genome-wide histone and DNA methylation emerged as being determinant of high ITH. Indeed, the knockout of histone methyltransferase SETD2 or DNA methyltransferase DNMT3A using the CRISPR/Cas9 system on cancer cells led to significant expansion of genetically-distinct clones and culminated in highly heterogeneous cell populations. The ITH scores observed in knockout cells recapitulated the heterogeneity levels observed in patient tumor samples and correlated with a better mitochondrial bioenergetic performance under stress conditions. Our work provides new insights into tumor development, and discloses new drivers of ITH, which may be useful as either predictive biomarkers or therapeutic targets to improve cancer treatment.

Quantitative Genetics Validates Previous Genetic Variants and Identifies Novel Genetic Players Influencing Alzheimer's Disease Cerebrospinal Fluid Biomarkers.

Cerebrospinal fluid (CSF) biomarkers have been extensively investigated in the Alzheimer's disease (AD) field, and are now being applied in clinical practice. CSF amyloid-beta (Aß1-42), total tau (t-tau), and phosphorylated tau (p-tau) reflect disease pathology, and may be used as quantitative traits for genetic analyses, fostering the identification of new genetic factors and the proposal of novel biological pathways of the disease. In patients, the concentration of CSF Aß1-42 is decreased due to the accumulation of Aß1-42 in amyloid plaques in the brain, while t-tau and p-tau levels are increased, indicating the extent of neuronal damage. To better understand the biological mechanisms underlying the regulation of AD biomarkers, and its relation to AD, we examined the association between 36 selected single nucleotide polymorphisms (SNPs) and AD biomarkers Aß1-42, t-tau, and p-tau in CSF in a cohort of 672 samples (571 AD patients and 101 controls) collected within 10 European consortium centers.Our results highlighted five genes, APOE, LOC100129500, PVRL2, SNAR-I, and TOMM40, previously described as main players in the regulation of CSF biomarkers levels, further reinforcing a role for these in AD pathogenesis. Three new AD susceptibility loci, INPP5D, CD2AP, and CASS4, showed specific association with CSF tau biomarkers. The identification of genes that specifically influence tau biomarkers point out to mechanisms, independent of amyloid processing, but in turn related to tau biology that may open new venues to be explored for AD treatment.