Premise and peril of Wnt signaling activation through GSK-3ß inhibition.

Wnt signaling pathways have been extensively studied in the context of several diseases, including cancer, coronary artery disease, and age-related disorders. ß-Catenin plays a central role in the most studied Wnt pathways, the Wnt/ß-catenin signaling pathway, commonly referred to as the canonical Wnt signaling pathway. ß-catenin is a substrate of glycogen synthase kinase 3ß (GSK-3ß), and the phosphorylated ß-catenin by GSK-3ß can be degraded by the proteasome through ubiquitination. Thus, GSK-3ß inhibitors have become a widely used chemical biology tool to study the canonical Wnt signaling pathway. Among the varied GSK-3ß inhibitors, a compound known as CHIR-99021 is one of the most widely used. Although these inhibitors contribute greatly to our understanding of the canonical Wnt pathway, certain pitfalls associated with such an approach may have been overlooked. In many published studies, micromolar concentrations of CHIR-99021 are used to activate the canonical Wnt pathway. Although CHIR-99021 is a specific GSK-3ß inhibitor, it specifically inhibits the kinase at the nanomolar level. Therefore, caution is required when micromolar levels of CHIR-99021 are used for the purpose of activating the canonical Wnt signaling pathway.

EMP2 Is a Novel Regulator of Stemness in Breast Cancer Cells.

Little is known about the role of epithelial membrane protein-2 (EMP2) in breast cancer development or progression. In this study, we tested the hypothesis that EMP2 may regulate the formation or self-renewal of breast cancer stem cells (BCSC) in the tumor microenvironment. In silico analysis of gene expression data demonstrated a correlation of EMP2 expression with known metastasis-related genes and markers of cancer stem cells (CSC) including aldehyde dehydrogenase (ALDH). In breast cancer cell lines, EMP2 overexpression increased and EMP2 knockdown decreased the proportion of stem-like cells as assessed by the expression of the CSC markers CD44+/CD24-, ALDH activity, or by tumor sphere formation. In vivo, upregulation of EMP2 promoted tumor growth, whereas knockdown reduced the ALDHhigh CSC population as well as retarded tumor growth. Mechanistically, EMP2 functionally regulated the response to hypoxia through the upregulation of HIF-1α, a transcription factor previously shown to regulate the self-renewal of ALDHhigh CSCs. Furthermore, in syngeneic mouse models and primary human tumor xenografts, mAbs directed against EMP2 effectively targeted CSCs, reducing the ALDH+ population and blocking their tumor-initiating capacity when implanted into secondary untreated mice. Collectively, our results show that EMP2 increases the proportion of tumor-initiating cells, providing a rationale for the continued development of EMP2-targeting agents.

Epithelial Membrane Protein-2 (EMP2) Antibody Blockade Reduces Corneal Neovascularization in an In Vivo Model.

Purpose: Pathologic corneal neovascularization is a major cause of blindness worldwide, and treatment options are currently limited. VEGF is one of the critical mediators of corneal neovascularization but current anti-VEGF therapies have produced limited results in the cornea. Thus, additional therapeutic agents are needed to enhance the antiangiogenic arsenal. Our group previously demonstrated epithelial membrane protein-2 (EMP2) involvement in pathologic angiogenesis in multiple cancer models including breast cancer and glioblastoma. In this paper, we investigate the efficacy of anti-EMP2 immunotherapy in the prevention of corneal neovascularization. Methods: An in vivo murine cornea alkali burn model was used to study pathologic neovascularization. A unilateral corneal burn was induced using NaOH, and subconjunctival injection of either anti-EMP2 antibody, control antibody, or sterile saline was performed after corneal burn. Neovascularization was clinically scored at 7 days postalkali burn, and eyes were enucleated for histologic analysis and immunostaining including VEGF, CD31, and CD34 expression. Results: Anti-EMP2 antibody, compared to control antibody or vehicle, significantly reduced neovascularization as measured by clinical score and central cornea thickness, as well as by histologic reduction of neovascularization, decreased CD34 staining, and decreased CD31 staining. Incubation of corneal limbal cells in vitro with anti-EMP2 blocking antibody significantly decreased EMP2 expression, VEGF expression and secretion, and cell migration. Conclusions: This work demonstrates the effectiveness of EMP2 as a novel target in pathologic corneal neovascularization in an animal model and supports additional investigation into EMP2 antibody blockade as a potential new therapeutic option.

Prospective Evaluation of Acupuncture as Treatment for Glaucoma.

PURPOSE: To evaluate acupuncture as treatment for glaucoma. DESIGN: Prospective double-masked randomized crossover study. METHODS: setting: Clinical practice. POPULATION: One eye per patient with primary open-angle glaucoma and stable intraocular pressure (IOP). INTERVENTION: Patients were randomized to receive 1 acupuncture series (12 sessions with either eye-related [eye-points] or non-eye-related [non-eye-points] acupoints) and then crossed over to receive the other series. OUTCOME MEASURES: IOP, blood pressure (BP), heart rate (HR), best-corrected visual acuity (BCVA), visual field (VF), optic disc and peripapillary retinal nerve fiber layer (RNFL) measurements, compliance, and adverse reactions. Probability to detect 3 mm Hg IOP difference between series was 90%. RESULTS: Twenty-two patients volunteered and 11 (50.0%) completed the study; 8 (36.4%) did not complete treatment owing to changes of health, moving away, lack of transportation, or family crisis; and 3(13.6%) were withdrawn owing to needle sensitivity or IOP elevation (8 mm Hg) in the contralateral eye. After an acupuncture session, mean IOP increased slightly with both eye-points (from 12.9 ± 1.8 mm Hg to 13.6 ± 2.0 mm Hg, P = .019) and non-eye-points (from 13.0 ± 1.5 mm Hg to 13.5 ± 1.7 mm Hg, P = .073) series. HR, diurnal IOP, and BCVA showed no statistically significant changes after 12 sessions of either series. Systolic and diastolic BP were reduced after 12 sessions of non-eye-points series (P = .040, P = .002, respectively). Optic disc, RNFL, and VF showed no statistically significant changes. CONCLUSIONS: Acupuncture has no overall effect on diurnal IOP or BCVA but may temporally increase the IOP immediately after a treatment session. BP is lowered by acupuncture with non-eye-points, but not with eye-points. Compliance and adverse event rates were low.