Human ERG oncoprotein represses a Drosophila LIM domain binding protein-coding gene Chip.

Human ETS Related Gene, ERG, a master transcription factor, turns oncogenic upon its out-of-context activation in diverse developmental lineages. However, the mechanism underlying its lineage-specific activation of Notch (N), Wnt, or EZH2-three well-characterized oncogenic targets of ERG-remains elusive. We reasoned that deep homology in genetic tool kits might help uncover such elusive cancer mechanisms in Drosophila. By heterologous gain of human ERG in Drosophila, here we reveal Chip, which codes for a transcriptional coactivator, LIM-domain-binding (LDB) protein, as its novel target. ERG represses Drosophila Chip via its direct binding and, indirectly, via E(z)-mediated silencing of its promoter. Downregulation of Chip disrupts LIM-HD complex formed between Chip and Tailup (Tup)-a LIM-HD transcription factor-in the developing notum. A consequent activation of N-driven Wg signaling leads to notum-to-wing transdetermination. These fallouts of ERG gain are arrested upon a simultaneous gain of Chip, sequestration of Wg ligand, and, alternatively, loss of N signaling or E(z) activity. Finally, we show that the human LDB1, a homolog of Drosophila Chip, is repressed in ERG-positive prostate cancer cells. Besides identifying an elusive target of human ERG, our study unravels an underpinning of its lineage-specific carcinogenesis.

Single-cell variations in the expression of codominant alleles A and B on RBC of AB blood group individuals.

A key question in biology is whether all cells of a given 'cell type' within an individual have more or less the same phenotype, especially in relation to nonimprinted autosomal loci. Some studies have shown differential allelic expression of autosomal genes to confer phenotypic variability at the individual cell level. Here, we report the amount of A and B histo-blood group antigens, products of classic examples of codominant alleles, in individual red blood cells (RBCs). Using immunofluorescence with Cy3-tagged and FITC-tagged antibodies, we quantified the levels of these antigens in 2512 RBCs from 24 individuals in the AB blood group. When these data were fit to a normal distribution, we could detect four groups: showing normal distribution for both antigens, either antigen, and neither antigen. Surprisingly, very few samples showed a significant positive correlation between the amounts of A and B antigens on individual RBC; in fact, the ratio of antigen A to antigen B in the entire set of samples spanned over five orders of magnitude. This variability in the amount of antigens A and/or B, combined with a lack of correlation between the amounts of these two antigens, resulted in unique staining patterns of RBC, generating widespread mosaicism in the RBC population of AB blood group individuals.

A Drosophila model of oral peptide therapeutics for adult intestinal stem cell tumors.

Peptide therapeutics, unlike small-molecule drugs, display crucial advantages of target specificity and the ability to block large interacting interfaces, such as those of transcription factors. The transcription co-factor of the Hippo pathway, YAP/Yorkie (Yki), has been implicated in many cancers, and is dependent on its interaction with the DNA-binding TEAD/Sd proteins via a large Ω-loop. In addition, the mammalian vestigial-like (VGLL) proteins, specifically their TONDU domain, competitively inhibit YAP-TEAD interaction, resulting in arrest of tumor growth. Here, we show that overexpression of the TONDU peptide or its oral uptake leads to suppression of Yki-driven intestinal stem cell tumors in the adult Drosophila midgut. In addition, comparative proteomic analyses of peptide-treated and untreated tumors, together with chromatin immunoprecipitation analysis, reveal that integrin pathway members are part of the Yki-oncogenic network. Collectively, our findings establish Drosophila as a reliable in vivo platform to screen for cancer oral therapeutic peptides and reveal a tumor suppressive role for integrins in Yki-driven tumors.This article has an associated First Person interview with the first author of the paper.

Hh signaling from de novo organizers drive lgl neoplasia in Drosophila epithelium.

The Hedgehog (Hh) morphogen regulates growth and patterning. Since Hh signaling is also implicated in carcinogenesis, it is conceivable that de novo Hh-secreting organizers, if formed in association with oncogenic hit could be tumor-cooperative. Here we validate this hypothesis using the Drosophila model of cooperative epithelial carcinogenesis. We generate somatic clones with simultaneous loss of tumor suppressor, Lgl, and gain of the posterior compartment selector, Engrailed (En), known to induce synthesis of Hh. We show that lgl UAS-en clones in the anterior wing compartment trigger Hh signaling cascade via cross-talk with their Ci-expressing wild type cell neighbors. Hh-Dpp signaling from clone boundaries of such ectopically formed de novo organizers in turn drive lgl carcinogenesis. By contrast, Ci-expressing lgl clones transform by autocrine and/or juxtracine activation of Hh signaling in only the posterior compartment. We further show that sequestration of the Hh ligand or loss of Dpp receptor, Tkv, in these Hh-sending or -receiving lgl clones arrested their carcinogenesis. Our results therefore reveal a hitherto unrecognized mechanism of tumor cooperation by developmental organizers, which are induced fortuitously by oncogenic hits.

Superabsorbent nanocomposite from sugarcane bagasse, chitin and clay: Synthesis, characterization and swelling behaviour.

A nanocomposite comprising crosslinked hybrid polymer network was prepared using chitin and sugarcane bagasse in presence of montmorillonite clay. Chitin and sugarcane bagasse were micro-fibrillated by ultrasonication of their suspension in an ionic liquid 2-hydroxy ethylammonium formate. Optimum reaction conditions were established by variation of amounts of initiator, monomer and crosslinker, and microwave irradiation to obtain nanocomposite with swelling degree above 1000% in 24 h. Slow and steady swelling was observed and the sample swelled to about 15,000% to form a hydrogel in 15 days. The nanocomposite was characterized by swelling degree, infrared spectroscopy, X-ray diffraction and scanning electron microscopy. Swelling and reswelling in water was studied for four cycles, erosion was highest after first cycle but became negligible for consecutive cycles. The swelling degree increased up to three cycles then became constant. Nanocomposite shows sufficient antimicrobial activity against S. aureus and E. coli. It is biodegradable in moist garden soil in three months.

Selector genes display tumor cooperation and inhibition in Drosophila epithelium in a developmental context-dependent manner.

During animal development, selector genes determine identities of body segments and those of individual organs. Selector genes are also misexpressed in cancers, although their contributions to tumor progression per se remain poorly understood. Using a model of cooperative tumorigenesis, we show that gain of selector genes results in tumor cooperation, but in only select developmental domains of the wing, haltere and eye-antennal imaginal discs of Drosophila larva. Thus, the field selector, Eyeless (Ey), and the segment selector, Ultrabithorax (Ubx), readily cooperate to bring about neoplastic transformation of cells displaying somatic loss of the tumor suppressor, Lgl, but in only those developmental domains that express the homeo-box protein, Homothorax (Hth), and/or the Zinc-finger protein, Teashirt (Tsh). In non-Hth/Tsh-expressing domains of these imaginal discs, however, gain of Ey in lgl- somatic clones induces neoplastic transformation in the distal wing disc and haltere, but not in the eye imaginal disc. Likewise, gain of Ubx in lgl- somatic clones induces transformation in the eye imaginal disc but not in its endogenous domain, namely, the haltere imaginal disc. Our results reveal that selector genes could behave as tumor drivers or inhibitors depending on the tissue contexts of their gains.

Epithelial neoplasia in Drosophila entails switch to primitive cell states.

Only select cell types in an organ display neoplasia when targeted oncogenically. How developmental lineage hierarchies of these cells prefigure their neoplastic propensities is not yet well-understood. Here we show that neoplastic Drosophila epithelial cells reverse their developmental commitments and switch to primitive cell states. In a context of alleviated tissue surveillance, for example, loss of Lethal giant larvae (Lgl) tumor suppressor in the wing primordium induced epithelial neoplasia in its Homothorax (Hth)-expressing proximal domain. Transcriptional profile of proximally transformed mosaic wing epithelium and functional tests revealed tumor cooperation by multiple signaling pathways. In contrast, lgl(-) clones in the Vestigial (Vg)-expressing distal wing epithelium were eliminated by cell death. Distal lgl(-) clones, however, could transform when both tissue surveillance and cell death were compromised genetically and, alternatively, when the transcription cofactor of Hippo signaling pathway, Yorkie (Yki), was activated, or when Ras/EGFR signaling was up-regulated. Furthermore, transforming distal lgl(-) clones displayed loss of Vg, suggesting reversal of their terminal cell fate commitment. In contrast, reinforcing a distal (wing) cell fate commitment in lgl(-) clones by gaining Vg arrested their neoplasia and induced cell death. We also show that neoplasia in both distal and proximal lgl(-) clones could progress in the absence of Hth, revealing Hth-independent wing epithelial neoplasia. Likewise, neoplasia in the eye primordium resulted in loss of Elav, a retinal cell marker; these, however, switched to an Hth-dependent primitive cell state. These results suggest a general characteristic of "cells-of-origin" in epithelial cancers, namely their propensity for switch to primitive cell states.

BRM-Parser: a tool for comprehensive analysis of BLAST and RepeatMasker results.

BLAST and Repeat Masker Parser (BRM-Parser) is a service that provides users a unified platform for easy analysis of relatively large outputs of BLAST (Basic Local Alignment Search Tool) and RepeatMasker programs. BLAST Summary feature of BRM-Parser summarizes BLAST outputs, which can be filtered using user defined thresholds for hit length, percentage identity and E-value and can be sorted by query or subject coordinates and length of the hit. It also provides a tool that merges BLAST hits which satisfy user-defined criteria for hit length and gap between hits. The RepeatMasker Summary feature uses the RepeatMasker alignment as an input file and calculates the frequency and proportion of mutations in copies of repeat elements, as identified by the RepeatMasker. Both features can be run through a GUI or can be executed via command line using the standalone version.