DIDO as a Switchboard that Regulates Self-Renewal and Differentiation in Embryonic Stem Cells.

Transition from symmetric to asymmetric cell division requires precise coordination of differential gene expression. We show that embryonic stem cells (ESCs) mainly express DIDO3 and that their differentiation after leukemia inhibitory factor withdrawal requires DIDO1 expression. C-terminal truncation of DIDO3 (Dido3ΔCT) impedes ESC differentiation while retaining self-renewal; small hairpin RNA-Dido1 ESCs have the same phenotype. Dido3ΔCT ESC differentiation is rescued by ectopic expression of DIDO3, which binds the Dido locus via H3K4me3 and RNA POL II and induces DIDO1 expression. DIDO1, which is exported to cytoplasm, associates with, and is N-terminally phosphorylated by PKCiota. It binds the E3 ubiquitin ligase WWP2, which contributes to cell fate by OCT4 degradation, to allow expression of primitive endoderm (PE) markers. PE formation also depends on phosphorylated DIDO3 localization to centrosomes, which ensures their correct positioning for PE cell polarization. We propose that DIDO isoforms act as a switchboard that regulates genetic programs for ESC transition from pluripotency maintenance to promotion of differentiation.

A lovastatin-elicited genetic program inhibits M2 macrophage polarization and enhances T cell infiltration into spontaneous mouse mammary tumors.

Beyond their ability to inhibit cholesterol biosynthesis, the statins have pleiotropic effects that include anti-inflammatory and immunomodulatory activities. Statins could have clinical utility, alone or in combination with other chemotherapeutics, in the treatment of cancer. The mechanisms that underlie the anti-tumor activity of the statins are nonetheless poorly defined. No studies have analyzed how they alter the tumor-associated leukocyte infiltrate, a central factor that influences tumor stroma and cancer evolution. Here we used HER2/neu transgenic (Tg-neu) mice to analyze the effect of lovastatin (Lov) on the inflammatory reaction of spontaneous mammary tumors. Lov treatment of tumor-bearing Tg-neu mice did not alter growth of established tumors, but significantly reduced the number of new oncogenic lesions in these mice. Moreover, Lov inhibited the growth of newly implanted Tg-neu tumors in immunocompetent but not in immunodeficient mice. We found that Lov enhanced tumor infiltration by effector T cells, and reduced the number of immunosuppressive and pro-angiogenic M2-like tumor-associated macrophages (TAM). Concomitantly, the drug improved the structure and function of the tumor vasculature, measured as enhanced tumor oxygenation and penetration of cytotoxic drugs. Microarray analysis identified a Lov-elicited genetic program in Tg-neu tumors that might explain these effects; we observed Lov-induced downregulation of placental growth factor, which triggers aberrant angiogenesis and M2-like TAM polarization. Our results identify a role for lovastatin in the shaping and re-education of the inflammatory infiltrate in tumors, with functional consequences in angiogenesis and antitumor immunity.

Changes in gene expression pattern of human primary macrophages induced by carbosilane dendrimer 2G-NN16.

PURPOSE: The use of dendrimers for biomedical applications has emerged with promising results. 2G-NN16 is a carbosilane dendrimer with sixteen positive charges per molecule tested to be capable to bind and release antisense oligonucleotides (ODNs) and small interference RNA (siRNA) in vitro. In spite of low cytotoxicity observed for these dendrimers, little is known about cellular changes they produce in cells in general and in immune cells in particular. MATERIALS AND METHODS: Genomic technologies allow us to identify global gene expression profile changes in macrophages exposed to a non-toxic concentration (5 microM) of 2G-NN16, alone or complexed with a random siRNA (dendriplex). Results were confirmed by quantitative real-time RT-PCR. RESULTS: Exposing macrophages to this dendrimer or dendriplex causes multiple gene expression changes, but no specific action of random siRNA was detected. Pathway analysis of differentially expressed genes shows the altered functions to be immune response, proliferation and transcription regulation. Interleukin 17F (IL17F) was the most regulated gene. CONCLUSIONS: Global gene expression profiles are a highly sensitive method to measure the toxicity degree of a gene delivery vehicle. The strong repression of IL17F, IL23R and IL23A, all of which are involved in autoimmune disease, by this particular dendrimer suggests a potential pharmacological application.