One-generation in vivo Drosophila genetic screening approach relevant to rhabdomyosarcoma

Galindo KA, Endicott TR, Avirneni-Vadlamudi U, Galindo RL. A rapid one-generation genetic screen in a Drosophila model to capture rhabdomyosarcoma effectors and therapeutic targets. G3 (Bethesda). 2014 Dec 9;5(2):205-17. PMID: 25491943; PMCID: PMC4321029.

From the abstract: "Rhabdomyosarcoma (RMS) is an aggressive childhood malignancy of neoplastic muscle-lineage precursors that fail to terminally differentiate into syncytial muscle. The most aggressive form of RMS, alveolar-RMS, is driven by misexpression of the PAX-FOXO1 oncoprotein ... Here, we report a new approach to dissect RMS, exploiting a highly efficient Drosophila PAX7-FOXO1 model uniquely configured to uncover PAX-FOXO1 RMS genetic effectors in only one generation. ... These studies show the utility of the PAX-FOXO1 Drosophila system as a robust one-generation (F1) RMS gene discovery platform and demonstrate how Drosophila transgenic conditional expression models can be configured for the rapid dissection of human disease. "

Fly cell screen leads to findings relevant to cancer treatment (and its financial impact)

Thomas S, Fisher KH, Snowden JA, Danson SJ, Brown S, Zeidler MP. Methotrexate Is a JAK/STAT Pathway Inhibitor. PLoS One. 2015 Jul 1;10(7):e0130078. PMID: 26131691.

From the abstract: "... The JAK/STAT pathway transduces signals from multiple cytokines and controls haematopoiesis, immunity and inflammation. In addition, pathological activation is seen in multiple malignancies including the myeloproliferative neoplasms (MPNs). Given this, drug development efforts have targeted the pathway with JAK inhibitors such as ruxolitinib. Although effective, high costs and side effects have limited its adoption. Thus, a need for effective low cost treatments remains. ...We used the low-complexity Drosophila melanogaster pathway to screen for small molecules that modulate JAK/STAT signalling. This screen identified methotrexate and the closely related aminopterin as potent suppressors of STAT activation. We show that methotrexate suppresses human JAK/STAT signalling without affecting other phosphorylation-dependent pathways. ... While the JAK1/2 inhibitor ruxolitinib is effective, a £43,200 annual cost precludes widespread adoption. With an annual methotrexate cost of around £32, our findings represent an important development with significant future potential."

Androgen Receptor & Prostate Cancer. From fly RNAi screen to human cell follow-up. Breaking report.

On my desk to read this President's Day? This report of a genome-wide RNAi screen performed with the NYU RNAi Core using the DRSC 2.0 genome-wide library.

Imberg-Kazdan K, Ha S, Greenfield A, Poultney CS, Bonneau R, Logan SK, Garabedian MJ. A genome-wide RNA interference screen identifies new regulators of androgen receptor function in prostate cancer cells. Genome Res. 2013 Feb 12. PubMed PMID: 23403032.

Breaking Report: Chemical Screen in RNAi knockdown background

On my desk to read this morning? A chemical screen in a background sensitized by RNAi. Screened in fly cells with follow-up in a mammalian system.

Gonsalves et al. 2011. An RNAi-based chemical genetic screen identifies three small-molecule inhibitors of the Wnt/wingless signaling pathway. Proc Natl Acad Sci U S A. 108(15):5954-63. PMID: 21393571; PubMed Central PMCID: PMC3076864.

Recent Review: miRNAs & Cancer

What's on my desk to read today? A recent review on miRNAs and cancer.

This review is not directly relevant to using RNAi for screens, of course. But Fig. 4 is a nice summary of tools for disrupting miRNAs. And I like to try to keep up with aspects of RNA biology, as understanding RNA biology is interlinked with exploiting it as a research tool.

Garzon et al. (2010) Targeting microRNAs in cancer: rationale, strategies and challenges. Nature Reviews Drug Discovery 9: 775-789. Available FREE.

Breaking Report: Chemical Screen in Fly Cells

What's on my desk this morning? A report from the Eggert lab on a chemical screen performed similar to a cell-based RNAi screen, and including knockdown of Rho in all cells by RNAi.

Castoreno et al. (2010) Small molecules discovered in a pathway screen target the Rho pathway in cytokinesis. Nat. Chem. Biol. 6(6):457-63. PMID 20436488.

(For further reading, see also Eggert et al. (2004) PLoS Biol. Dec;2(12):e379. Parallel chemical genetic and genome-wide RNAi screens identify cytokinesis inhibitors and targets. Describes the results of RNAi screening performed at the DRSC and a chemical screen.)

Breaking Report: Fly Model of Leukemia

On my desk today? Osman et al. (2009) A Drosophila model identifies calpains as modulators of the human leukemogenic fusion protein AML1-ETO. In PNAS. PubMed ID 19581587. The authors report a model of AML1-ETO-induced leukemia. Includes results of an in vivo screen using the collection of the National Institute of Genetics (of Japan, I assume). See LINK for information about that fly stock collection.

Quote of the Week

If genius is the ability to reduce the complicated to the simple, then the study of p53 makes fools of us all.

Voudsden & Prives (2009) in the review, Blinded by the Light: the Growing Complexity of p53. Cell 137(3):413-431

Breaking Report: Divisions Gone Wrong

What's on my desk today? A paper on a Drosophila kinase RNAi screen and a very recent report that extends the results to a specific topic in human disease.

Bettencourt-Dias et al. (2004) Genome-wide survey of protein kinases required for cell cycle progression. Nature 432:980-987. At PubMed.

Wang et al. (2009) Association of genetic variation in mitotic kinases with breast cancer risk. Breast Cancer Res. Treat. DOI 10.1007/s10549-009-0404-3. At PubMed.

Related Links:

DRSC Kinase & Phosphatase Sub-Library (on- or off-site screening).

Transgenic RNAi Project (TRiP) stock list (click to expand the current list, download the xls file, open in Excel, and see Column H on the spreadsheet to view which hairpin lines target kinase-encoding genes).

Breaking Report: A Look at Centromeres

What am I reading today? Another paper that reports results from a genome-wide study performed at the DRSC: Erhardt et al. (2008) Genome-wide analysis reveals a cell cycle-dependent mechanism controlling centromere propagation. JCB 183(5):805-818.

The authors describe the results of a full-genome screen for factors that disrupt the normal localization of CENP-A (CID). Protocol Notes: A fluorescence image-based screen assay in Kc167 cells. The authors provide a nicely detailed description of the screening protocol, including info on image analysis, in the Materials & Methods section. Follow-up includes time-lapse and additional imaging in S2 cells and fly embryos. Plus IP from Kc167 cells.