Excessive antigen reactivity may underlie the clinical aggressiveness of chronic lymphocytic leukemia stereotyped subset #8

Subset #8 is a distinctive subset of patients with chronic lymphocytic leukemia (CLL) defined by the expression of stereotyped IGHV4-39/IGKV1(D)-39 B-cell receptors. Subset #8 patients experience aggressive disease and exhibit the highest risk for Richter transformation among all CLL. In order to obtain biological insight into this behavior, we profiled the antigen reactivity and signaling capacity of subset #8 vs other clinically aggressive stereotyped subsets, namely subsets #1 and #2. Twenty-seven monoclonal antibodies (mAbs) from subsets #1, #2, and #8 CLL clones were prepared as recombinant human immunoglobulin G1 and used as primary antibodies in enzyme-linked immuno-sorbent assays against representatives of the major classes of established antigenic targets for CLL. Subset #8 CLL mAbs exhibited broad polyreactivity as they bound to all antigens tested, in clear contrast with the mAbs from the other subsets. Antigen challenge of primary CLL cells indicated that the promiscuous antigen-binding activity of subset #8 mAbs could lead to significant cell activation, again in contrast to the less responsive CLL cells from subsets #1 and #2. These features constitute a distinctive profile for CLL subset #8, supporting the existence of distinct mechanisms of aggressiveness in different immunogenetic subsets of CLL

Paclitaxel Magnetic Core⁻Shell Nanoparticles Based on Poly(lactic acid) Semitelechelic Novel Block Copolymers for Combined Hyperthermia and Chemotherapy Treatment of Cancer.

Magnetic hybrid inorganic/organic nanocarriers are promising alternatives for targeted cancer treatment. The present study evaluates the preparation of manganese ferrite magnetic nanoparticles (MnFe2O4 MNPs) encapsulated within Paclitaxel (PTX) loaded thioether-containing ω-hydroxyacid-co-poly(d,l-lactic acid) (TEHA-co-PDLLA) polymeric nanoparticles, for the combined hyperthermia and chemotherapy treatment of cancer. Initially, TEHA-co-PDLLA semitelechelic block copolymers were synthesized and characterized by 1H-NMR, FTIR, DSC, and XRD. FTIR analysis showed the formation of an ester bond between the two compounds, while DSC and XRD analysis showed that the prepared copolymers were amorphous. MnFe2O4 MNPs of relatively small crystallite size (12 nm) and moderate saturation magnetization (64 emu·g-1) were solvothermally synthesized in the sole presence of octadecylamine (ODA). PTX was amorphously dispersed within the polymeric matrix using emulsification/solvent evaporation method. Scanning electron microscopy along with energy-dispersive X-ray spectroscopy and transmission electron microscopy showed that the MnFe2O4 nanoparticles were effectively encapsulated within the drug-loaded polymeric nanoparticles. Dynamic light scattering measurements showed that the prepared nanoparticles had an average particle size of less than 160 nm with satisfactory yield and encapsulation efficiency. Diphasic PTX in vitro release over 18 days was observed while PTX dissolution rate was mainly controlled by the TEHA content. Finally, hyperthermia measurements and cytotoxicity studies were performed to evaluate the magnetic response, as well as the anticancer activity and the biocompatibility of the prepared nanocarriers

beta-Catenin induces T-cell transformation by promoting genomic instability

Deregulated activation of β-catenin in cancer has been correlated with genomic instability. During thymocyte development, β-catenin activates transcription in partnership with T-cell-specific transcription factor 1 (Tcf-1). We previously reported that targeted activation of β-catenin in thymocytes (CAT mice) induces lymphomas that depend on recombination activating gene (RAG) and myelocytomatosis oncogene (Myc) activities. Here we show that these lymphomas have recurring Tcra/Myc translocations that resulted from illegitimate RAG recombination events and resembled oncogenic translocations previously described in human TALL. We therefore used the CAT animal model to obtain mechanistic insights into the transformation process. ChIP-seq analysis uncovered a link between Tcf-1 and RAG2 showing that the two proteins shared binding sites marked by trimethylated histone-3 lysine-4 (H3K4me3) throughout the genome, including near the translocation sites. Pretransformed CAT thymocytes had increased DNA damage at the translocating loci and showed altered repair of RAG-induced DNA double strand breaks. These cells were able to survive despite DNA damage because activated β-catenin promoted an antiapoptosis gene expression profile. Thus, activated β-catenin promotes genomic instability that leads to T-cell lymphomas as a consequence of altered double strand break repair and increased survival of thymocytes with damaged DNA.link_to_OA_fulltex

Global Regulator SATB1 Recruits β-Catenin and Regulates TH2 Differentiation in Wnt-Dependent Manner

Chromatin organizer SATB1 and Wnt transducer β-catenin form a complex and regulate expression of GATA3 and TH2 cytokines in Wnt-dependent manner and orchestrate TH2 lineage commitment

Double Negative (CD3+4−8−) TCRαβ Splenic Cells from Young NOD Mice Provide Long-Lasting Protection against Type 1 Diabetes

-reactive T-cells. Herein, we analyzed the function and phenotype of DNCD3 splenic cells in young NOD mice predisposed to several autoimmune disorders among which, the human-like autoimmune diabetes. with a predominant Vβ13 gene usage.T-regulatory cells. DNCD3 splenic cells could be potentially manipulated towards the development of autologous cell therapies in autoimmune diabetes

A DNA Sequence Directed Mutual Transcription Regulation of HSF1 and NFIX Involves Novel Heat Sensitive Protein Interactions

BACKGROUND: Though the Nuclear factor 1 family member NFIX has been strongly implicated in PDGFB-induced glioblastoma, its molecular mechanisms of action remain unknown. HSF1, a heat shock-related transcription factor is also a powerful modifier of carcinogenesis by several factors, including PDGFB. How HSF1 transcription is controlled has remained largely elusive. METHODOLOGY/PRINCIPAL FINDINGS: By combining microarray expression profiling and a yeast-two-hybrid screen, we identified that NFIX and its interactions with CGGBP1 and HMGN1 regulate expression of HSF1. We found that CGGBP1 organizes a bifunctional transcriptional complex at small CGG repeats in the HSF1 promoter. Under chronic heat shock, NFIX uses CGGBP1 and HMGN1 to get recruited to this promoter and in turn affects their binding to DNA. Results show that the interactions of NFIX with CGGBP1 and HMGN1 in the soluble fraction are heat shock sensitive due to preferential localization of CGGBP1 to heterochromatin after heat shock. HSF1 in turn was found to bind to the NFIX promoter and repress its expression in a heat shock sensitive manner. CONCLUSIONS/SIGNIFICANCE: NFIX and HSF1 exert a mutual transcriptional repressive effect on each other which requires CGG repeat in HSF1 promoter and HSF1 binding site in NFIX promoter. We unravel a unique mechanism of heat shock sensitive DNA sequence-directed reciprocal transcriptional regulation between NFIX and HSF1. Our findings provide new insights into mechanisms of transcription regulation under stress

Activation of Wnt Signaling by Chemically Induced Dimerization of LRP5 Disrupts Cellular Homeostasis

Wnt signaling is crucial for a variety of biological processes, including body axis formation, planar polarity, stem cell maintenance and cellular differentiation. Therefore, targeted manipulation of Wnt signaling in vivo would be extremely useful. By applying chemical inducer of dimerization (CID) technology, we were able to modify the Wnt co-receptor, low-density lipoprotein (LDL)-receptor-related protein 5 (LRP5), to generate the synthetic ligand inducible Wnt switch, iLRP5. We show that iLRP5 oligomerization results in its localization to disheveled-containing punctate structures and sequestration of scaffold protein Axin, leading to robust β-catenin-mediated signaling. Moreover, we identify a novel LRP5 cytoplasmic domain critical for its intracellular localization and casein kinase 1-dependent β-catenin signaling. Finally, by utilizing iLRP5 as a Wnt signaling switch, we generated the Ubiquitous Activator of β-catenin (Ubi-Cat) transgenic mouse line. The Ubi-Cat line allows for nearly ubiquitous expression of iLRP5 under control of the H-2Kb promoter. Activation of iLRP5 in isolated prostate basal epithelial stem cells resulted in expansion of p63+ cells and development of hyperplasia in reconstituted murine prostate grafts. Independently, iLRP5 induction in adult prostate stroma enhanced prostate tissue regeneration. Moreover, induction of iLRP5 in male Ubi-Cat mice resulted in prostate tumor progression over several months from prostate hyperplasia to adenocarcinoma. We also investigated iLRP5 activation in Ubi-Cat-derived mammary cells, observing that prolonged activation results in mammary tumor formation. Thus, in two distinct experimental mouse models, activation of iLRP5 results in disruption of tissue homeostasis, demonstrating the utility of iLRP5 as a novel research tool for determining the outcome of Wnt activation in a precise spatially and temporally determined fashion