D. Faingold

Molecular Pathways Mediating Liver Metastasis in Patients with Uveal Melanoma

Uveal melanoma arises from melanocytes located in the uveal tract of the eye and is the most common primary intraocular tumor in adults. Metastatic liver disease is the overwhelming cause of death in uveal melanoma patients, with almost 50% of patients developing liver metastases up to 15 years after diagnosis. Most of these patients do not present with any evidence of overt metastasis at the time of initial diagnosis although it is assumed that they have undetectable micrometastases. Currently, there are no therapeutic modalities to prevent or efficiently treat the metastatic disease in uveal melanoma patients. Recent discoveries have shed light on the molecular pathways that may contribute to the progression of liver metastasis. The aim of this review is to describe new insights into the genetic and molecular pathways that may play a role in the development of liver metastases in uveal melanoma patients.

Assessment of retinal hemodynamics with the Canon laser blood flowmeter after a single dose of 2 % dorzolamide hydrochloride eyedrops

BACKGROUND Dorzolamide hydrochloride is a carbonic anhydrase inhibitor that reduces intraocular pressure (IOP) by decreasing the production of aqueous humour in the ciliary body. Theoretically, topical use of this agent has the potential to directly affect retinal vasculature through local induced acidosis. We performed a study to determine whether there are changes in retinal arteriole hemodynamics, as assessed with the Canon laser blood flowmeter, in healthy subjects following topical administration of dorzolamide. METHODS We recruited 17 healthy volunteers, nine men and eight women aged 25 to 55 years (mean 31.4 [standard deviation (SD) 9.88] years). The inclusion criteria were Snellen visual acuity of 20/30 or better, normal anterior eye examination, IOP of 21 mm Hg or less, and a normal fundus appearance. One eye of each subject was randomly assigned to receive a drop of 2% dorzolamide. The contralateral eye of 10 of the subjects received a placebo drop (artificial tears). Before and 1 hour after drop administration, we obtained blood flow measurements from an inferotemporal arteriole approximately 1 disc diameter from the optic nerve head rim using the Canon laser blood flowmeter, model 100. The IOP was measured by means of Goldmann applanation tonometry before and 1 hour after drop administration. RESULTS The mean IOP was significantly reduced in the dorzolamide-treated eyes, from 14.4 mm Hg (SD 2.94 mm Hg) to 11.7 mm Hg (SD 2.50 mm Hg) (p < 0.001). The IOP was also reduced in the placebo group (15.6 mm Hg [SD 3.41 mm Hg] vs. 14.6 mm Hg [SD 3.28 mm Hg]), but the difference was not significant. There was no significant difference in mean arteriole diameter, mean blood velocity or mean blood flow after drug administration in the dorzolamide-treated eyes. INTERPRETATION Our results indicate that a single topical application of dorzolamide in healthy subjects has no effect on retinal arteriole diameter, blood velocity or blood flow, as measured with the Canon laser blood flowmeter. Longer-term studies of retinal hemodynamics in patients with glaucoma are warranted as evolving treatments aim to improve ocular blood flow as well as reduce IOP.

Immune Expression and Inhibition of Heat Shock Protein 90 in Uveal Melanoma

Purpose: To examine the immunohistochemical profile of heat shock protein 90 (Hsp90) in uveal melanoma and the cytotoxicity of an Hsp90 inhibitor, 17-allylamino-17-demethoxygeldanamycin (17-AAG), in uveal melanoma cell lines. Experimental Design: Hsp90 expression was determined by immunohistochemistry in 44 paraffin-embedded sections of primary human uveal melanoma and in five uveal melanoma cell lines (92.1, OCM-1, MKT-BR, SP6.5, and UW-1). Sulforhodamine B–based proliferation assay was used to compare uveal melanoma cell growth with a range of concentrations of 17-AAG. Changes in cell migration, invasion, cell cycle fractions, and apoptotic activity were also evaluated. Expression of intracellular proteins was determined by Western blot analysis after 17-AAG exposure. Results: Immunohistochemical expression of Hsp90 was identified in 68% of the paraffin-embedded sections and significantly associated with largest tumor dimension (P = 0.03). 17-AAG significantly reduced the proliferation rates of uveal melanoma cell lines, with concentrations of 100 to 0.1 μmol/L. 17-AAG also significantly reduced the migratory and invasive capabilities of uveal melanoma cell lines. Cell cycle analysis showed that 17-AAG induced accumulations of cells in G1. Caspase-3 protease activity analysis, a marker for apoptosis, showed a significant increase after drug exposure. The cytotoxic effect of 17-AAG was associated with decreased levels of phosphorylated Akt and cyclin-dependent kinase 4. Conclusions: The immunohistochemical expression of Hsp90 in uveal melanoma indicates worse prognosis. To the best of our knowledge, this is the first report showing the inhibitory effect on uveal melanoma cells using 17-AAG to target Hsp90. Therefore, Hsp90 may be used as a potential target for treatment of patients with uveal melanoma.

Expression of focal adhesion kinase in uveal melanoma and the effects of Hsp90 inhibition by 17-AAG.

INTRODUCTION Focal adhesion kinase (FAK) is implicated in tumor progression and metastatic cascade, and has been shown to be overexpressed in a variety of human cancers. However, the role of FAK in human uveal melanoma (UM) is not well defined. The purpose of this study was to evaluate the expression of FAK in UM tumors and normal eyes, and to determine the effect of Hsp90 inhibition on FAK expression in UM cells. METHODS FAK expression was assessed in 39 UM specimens, FAK[pY397] expression was assessed in 51 UM specimens, and both FAK and FAK[pY397] expression were assessed in 20 normal eyes. The expression of FAK and FAK[pY397] was detected by Western blot in five UM cell lines after treatment with 10 μmol/L of 17-AAG. RESULTS FAK was positive in 87.2% and FAK[pY397] in 90% of UM specimens. Low FAK expression was detected in non-tumor structures and in normal eyes. The cell lines with the most proliferative, invasive phenotype (92.1, SP6.5 and MKT-BR) displayed high expression of FAK[pY397], and the levels of FAK and FAK[pY397] were decreased in the presence of 17-AAG starting with 24 h of exposure. CONCLUSION FAK and FAK[pY397] were overexpressed in human UM tumors compared to normal ocular tissue and high levels of FAK[pY397] were seen in the most aggressive UM cell lines. Hsp90 inhibition led to downregulation of FAK expression. We propose a role for FAK in the pathogenesis of UM. Future studies are needed to explore the use of Hsp90 inhibitors as a feasible approach for modulating FAK in UM.

Expanded indications for transconjunctival trabeculectomy flap suturing: postoperative choroidal effusion and dysesthesia.

OBJECTIVE To assess the efficacy of transconjunctival trabeculectomy flap suturing (TTFS) in improving choroidal effusions and bleb dysesthesia resulting from overfiltration after trabeculectomy. DESIGN Retrospective review. PARTICIPANTS The study involved 15 eyes of 15 patients. METHODS Patients underwent TTFS for choroidal effusions and bleb dysesthesia following trabeculectomy using mitomycin C. The scleral flap was sutured through the conjunctiva as an outpatient clinic procedure. RESULTS There were 11 patients who had choroidal effusions and 4 patients were identified with dysesthesia. The average duration of choroidal effusion prior to TTFS was 2.1 ± 2.3 months and 3 ± 2 months in the dysesthesia group. At the final follow-up (25 ± 17 months) the mean intraocular pressure improved from 4.1 ± 2.1 mm Hg before suturing to 8.1 ± 3.6 mm Hg (p < 0.007) for the patients with choroidal effusion and from 4.2 ± 0.6 mm Hg to 8. 7 ± 3.5 mm Hg (p = 0.05) for the patients with dysesthesia. In both groups, resolution of the signs and symptoms was achieved in all cases. The mean time to resolution of choroidal effusions was 5.5 ± 8.6 weeks and the mean time to resolution of dysesthesia was 2 ± 0.8 weeks. None of the patients had serious complications such as failure of the trabeculectomy or visual loss. CONCLUSIONS Transconjunctival suturing of the trabeculectomy scleral flap is a simple and effective surgical method for the treatment of cases of choroidal effusions or dysesthesia resulting from trabeculectomy.

Analysis of HSP90 Expression Is Valuable in the Differential Diagnosis of Ocular Surface Squamous Lesions

OBJECTIVES The aim of this study was to evaluate heat shock protein 90 (HSP90) expression in squamous lesions (SLs) and to assess its diagnostic value for different lesions within the SL spectrum. METHODS A total of 70 conjunctival SLs, including 19 papillomas, 22 cases of conjunctival intraepithelial neoplasia (ConINs) I, 11 cases of ConIN II, six cases of ConIN III, and 12 squamous carcinomas (sqCAs), were evaluated using the German immunoreactive score against HSP90. RESULTS Cytoplasmic HSP90 expression differed between low- and high-grade lesions (P < .001). Among high-grade lesions, the nuclear HSP90 score was higher in the ConIN III-sqCA group than in the ConIN II group (P = .0162). A percentage of total thickness staining of less than 73% differentiated between ConIN III and sqCA. CONCLUSIONS The expression of HSP90 is particularly useful to differentiate low-grade from high-grade lesions of the conjunctiva. HSP90 may play an important role in the malignant transformation of SLs and could be a new target for therapy.

Prerequisite Genetic Traits for Metastasis

The genetic and epigenetic abnormalities in tumors influence the metastatic traits of disseminated cells by activation of oncogenes and inactivation of tumor-suppressor genes. Tumor-suppressor genes affect genome stability, cancer-cell survival and growth while also being involved in the response and repair of DNA. They are a part of the prerequisites for metastasis and determine initiation and continuous development of the oncogenic process resulting in unrestricted proliferation and resistance to cell death signals. Inactivation of tumor suppressor genes can occur through various mechanisms such as loss of heterozygosity and chromosomal damage as well as by genetic mutations and epigenetic mechanisms such as promoter hypermethylation (Nguyen and Massague 2007; Eccles 2005). The amplification and mutation of oncogenes in primary tumors, together with the selective pressures of the tumor microenvironment play a key role in the formation of metastasis (Bernards and Weinberg 2002).

A view of VEGF in ocular melanoma: prospective implications for patient care

Evaluation of: Missotten GS, Notting IC, Schlingemann RO et al. Vascular endothelial growth factor a in eyes with uveal melanoma. Arch. Ophthalmol. 124, 1428–1434 (2006). A recent publication has shown the presence and origin of vascular endothelial growth factor (VEGF)-A in the aqueous, tumor tissue and surrounding retina of patients with uveal melanoma. The study was able to correlate VEGF-A expression with worse patient outcome. For the first time, the authors demonstrate the source of VEGF-A production in this malignancy in vivo, thereby opening a new route for potential therapeutic interventions. In this key paper evaluation, we review the literature regarding the potential role of VEGF-A and implications for uveal melanoma patient care.