Xiaoyan Li

Down-regulation of E-cadherin marks the initiation of the epithelial-mesenchymal transition, a process exploited by invasive cancer cells. The zinc finger transcription factor, Snail, functions as a potent repressor of E-cadherin expression that can, acting alone or in concert with the Wnt/beta-catenin/T cell factor axis, induce an epithelial-mesenchymal transition. Although mechanisms that coordinate signaling events initiated by Snail and Wnt remain undefined, we demonstrate that Snail displays beta-catenin-like canonical motifs that support its GSK3beta-dependent phosphorylation, beta-TrCP-directed ubiquitination, and proteasomal degradation. Accordingly, Wnt signaling inhibits Snail phosphorylation and consequently increases Snail protein levels and activity while driving an in vivo epithelial-mesenchymal transition that is suppressed following Snail knockdown. These findings define a potential mechanism whereby Wnt signaling stabilizes Snail and beta-catenin proteins in tandem fashion so as to cooperatively engage transcriptional programs that control an epithelial-mesenchymal transition.

In Brief Purpose: To evaluate the safety and efficacy of Ozurdex (dexamethasone intravitreal implant) 0.7 mg in the treatment of diabetic macular edema in vitrectomized eyes. Methods: This was a prospective, multicenter, open-label, 26-week study. Fifty-five patients with treatment-resistant diabetic macular edema and a history of previous pars plana vitrectomy in the study eye received a single intravitreal injection of 0.7-mg dexamethasone intravitreal implant. The primary efficacy outcome measure was the change in central retinal thickness from baseline to Week 26 measured by optical coherence tomography. Results: The mean age of patients was 62 years. The mean duration of diabetic macular edema was 43 months. The mean (95% confidence interval) change from baseline central retinal thickness (403 μm) was −156 μm (−190, −122 μm) at Week 8 (P < 0.001) and −39 μm (−65, −13 μm) at Week 26 (P = 0.004). The mean (95% CI) increase in best-corrected visual acuity from baseline (54.5 letters) was 6.0 letters (3.9, 8.1 letters) at Week 8 (P < 0.001) and 3.0 letters (0.1, 6.0 letters) at Week 26 (P = 0.046). At Week 8, 30.4% of patients had gained ≥10 letters in best-corrected visual acuity. Conjunctival hemorrhage, conjunctival hyperemia, eye pain, and increased intraocular pressure were the most common adverse events. Conclusion: Treatment with dexamethasone intravitreal implant led to statistically and clinically significant improvements in both vision and vascular leakage from diabetic macular edema in difficult-to-treat vitrectomized eyes and had an acceptable safety profile. A 26-week, open-label study evaluated the safety and efficacy of a sustained-release dexamethasone intravitreal implant for treatment of diabetic macular edema in eyes with previous vitrectomy. Dexamethasone intravitreal implant had an acceptable safety profile and effectively reduced central retinal thickness and improved visual acuity in difficult-to-treat vitrectomized eyes.

Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein that triggers caspase-independent apoptosis. We describe here the cloning and characterization of a novel AIF-homologous molecule designated AMID (AIF-homologous mitochondrion-associated inducer of death). AMID lacks a mitochondrial localization sequence but shares significant homology with AIF and NADH oxidoreductases from bacteria to mammalian species. Immunofluorescent staining and biochemical experiments indicated that AMID was co-localized with mitochondria. Overexpression of AMID induced cell death with characteristic apoptotic morphology. Furthermore, AMID-induced apoptosis was independent of caspase activation and p53 and was not inhibited by Bcl-2. These findings suggest that AMID induces a novel caspase-independent apoptotic pathway.