Phase I/II study of pegylated arginine deiminase (ADI-PEG 20) in patients with advanced melanoma

Background Arginine deiminase (ADI) is an enzyme that degrades arginine, an amino acid that is important for growth and development of normal and neoplastic cells. Melanoma cells are auxotrophic for arginine, because they lack argininosuccinatesynthetase (ASS), a key enzyme required for the synthesis of arginine. Patients and methods Patients with advanced melanoma were treated with 40, 80 or 160 IU/m(2) ADI-PEG 20 i.m. weekly. Primary endpoints were toxicity and tumor response, secondary endpoints included metabolic response by (18)FDG-PET, pharmacodynamic (PD) effects upon circulating arginine levels, and argininosuccinate synthetase tumor expression by immunohistochemistry. Results 31 previously treated patients were enrolled. The main toxicities were grade 1 and 2 adverse events including injection site pain, rash, and fatigue. No objective responses were seen. Nine patients achieved stable disease (SD), with 2 of these durable for >6 months. Four of the 9 patients with SD had uveal melanoma. PD analysis showed complete plasma arginine depletion in 30/31 patients by day 8. Mean plasma levels of ADI-PEG 20 correlated inversely with ADI-PEG 20 antibody levels. Immunohistochemical ASS expression analysis in tumor tissue was negative in 24 patients, whereas 5 patients had <5 % cells positive. Conclusions ADI-PEG 20 is well tolerated in advanced melanoma patients and leads to consistent, but transient, arginine depletion. Although no RECIST responses were observed, the encouraging rate of SD in uveal melanoma patients indicates that it may be worthwhile to evaluate ADI-PEG 20 in this melanoma subgroup.

Expression of haematogenous and lymphogenous chemokine receptors and their ligands on uveal melanoma in association with liver metastasis

PURPOSE

Chemokine receptors and their ligands are involved in a number of cell processes, including normal cell trafficking as well as metastasis in cancer. During metastasis, they are thought to play a role in determining cancer cell distribution and target organs. The aim of this study was to examine the expression of the chemokine receptors CXCR4, CCR7 and CCR10 as well as their respective chemokine ligands (CXCL12, CCL19, CCL27) in human uveal melanomas.

METHODS

Seventy formalin-fixed paraffin-embedded uveal melanoma specimens from patients treated in 1996-1997 were examined using immunohistochemistry and evaluated using an immune reactive score (IRS).

RESULTS

The chemokine receptors CXCR4, CCR7 and CCR10 were primarily expressed in the cytoplasm of uveal melanoma cells, with CXCR4 (average IRS 8.2) and CCR7 (average IRS 5.7) showing the strongest expression, respectively. The chemokine ligand CCL19 demonstrated a moderate expression (average IRS 5.3), whereas the expression of receptor CCR10 (average IRS of 3.4), ligand CCL27 (average IRS 2.5) and ligand CXCL12 (average IRS 0.6) by uveal melanoma cells was low. A significant association between liver metastases and chemokine expression was found for CCR7 expression (p = 0.037) only. Comparison of liver metastasis and choroid uveal melanoma (35.3%, n = 12 of 34) versus ciliary body involvement (72.7%, n = 8 of 11) was significant (p = 0.030).

CONCLUSION

Chemokine receptors are more strongly expressed on uveal melanoma cells than their ligands. Our results show new aspects of the metastatic process in uveal melanoma.

The pharmacological NF-κB inhibitor BAY11-7082 induces cell apoptosis and inhibits the migration of human uveal melanoma cells

Uveal melanomas are highly metastatic and have high rate of recurrence due to the lack of effective systemic therapy. The identification of important survival pathways in uveal melanomas provides novel therapeutic targets for effective treatment. In the present study, we found that the NF-κB signaling pathway was constitutively and highly activated in uveal melanoma cells. Treatment with the pharmacological NF-κB specific inhibitor BAY11-7082 markedly decreased the nuclear translocation of NF-κB. In a dose-dependent setting, BAY11-7082 inhibited the proliferation and growth of uveal melanoma cells by inducing apoptosis without effect on cell cycle. The migration capacity of uveal melanoma cells was also significantly suppressed by BAY11-7082 treatment. Mechanistically, BAY11-7082 increased the activity of caspase 3 and reduced the expression of anti-apoptotic protein Bcl-2, but did not influence the expression of pro-apoptotic protein Bax. Furthermore, BAY11-7082 induced uveal melanoma cell apoptosis and inhibited xenograft tumor growth in vivo. Collectively, the present study identified NF-κB as an important survival signal for uveal melanoma cells and suggested that administration of specific NF-κB inhibitor BAY11-7082 could serve as an effective treatment for patients with uveal melanoma.

HSP-27 protein expression in uveal melanoma: correlation with predicted survival

PURPOSE

Almost 40% of uveal melanomas (UM) are fatal, because of metastatic disease that usually involves the liver. Partial or complete deletion of chromosome 3 (i.e., monosomy 3) is a strong predictor of metastatic mortality; however, genetic analysis is not always possible. The aim of this study was to determine whether heat shock protein 27 (HSP-27) protein expression could reliably predict prognosis.

METHODS

Immunohistochemical analysis of HSP-27 protein expression was performed on formalin-fixed, paraffin-embedded sections from 99 UM of known chromosome 3 status, as determined by multiplex ligation-dependent probe amplification. Slides were evaluated blind by three independent observers. The percentage of tumour cells staining for HSP-27 was categorized as: 0 (<1%); 1 (1-24%); 2 (25-49%); 3 (50-74%) or 4 (>74%). The staining intensity was categorized as: 0 (no staining); 1 (weak); 2 (moderate) and 3 (strong). These two categories were multiplied together to obtain the HSP-27 expression score. All data were processed in spss for statistical analyses.

RESULTS

Heat shock protein 27 score was lower in monosomy 3 melanomas than in disomy 3 tumours (p<0.001; Mann-Whitney U-test). An 'accelerated failure time model' was used to generate predicted survival for all patients included in the study. Kaplan-Meier analysis indicated a significantly decreased predicted 8-year survival rate for patients with an HSP-27 Score≤6 (p=0.03; Log rank test). Predicting monosomy 3 was enhanced by considering the HSP-27 score together with basal tumour diameter, melanoma cytomorphology and mitotic rate.

CONCLUSIONS

Low HSP-27 expression correlates with monosomy 3 in UM and with increased predicted mortality. When assessed together with other clinical and pathological variables, the HSP-27 score enhances estimation of survival probability.

Role of microRNA-182 in posterior uveal melanoma: regulation of tumor development through MITF, BCL2 and cyclin D2

MicroRNAs (miRNAs) are endogenous small non-coding RNAs that play central roles in diverse pathological processes. In this study, we investigated the effect of microRNA-182 (miR-182) on the development of posterior uveal melanomas. Initially, we demonstrated that miR-182 expression was dependent on p53 induction in uveal melanoma cells. Interestingly, transient transfection of miR-182 into cultured uveal melanoma cells led to a significant decrease in cell growth, migration, and invasiveness. Cells transfected with miR-182 demonstrated cell cycle G1 arrest and increased apoptotic activity. Using bioinformatics, we identified three potential targets of miR-182, namely MITF, BCL2 and cyclin D2. miR-182 was shown to have activity on mRNA expression by targeting the 3' untranslated region of MITF, BCL2 and cyclin D2. Subsequent Western blot analysis confirmed the downregulation of MITF, BCL2 and cyclin D2 protein expression. The expression of oncogene c-Met and its downstream Akt and ERK1/2 pathways was also downregulated by miR-182. Concordant with the findings that miR-182 was decreased in uveal melanoma tissue samples, overexpression of miR-182 also suppressed the in vivo growth of uveal melanoma cells. Our results demonstrated that miR-182, a p53 dependent miRNA, suppressed the expression of MITF, BCL2, cyclin D2 and functioned as a potent tumor suppressor in uveal melanoma cells.

ALCAM regulates motility, invasiveness, and adherens junction formation in uveal melanoma cells

ALCAM, a member of the immunoglobulin superfamily, has been implicated in numerous developmental events and has been repeatedly identified as a marker for cancer metastasis. Previous studies addressing ALCAM's role in cancer have, however, yielded conflicting results. Depending on the tumor cell type, ALCAM expression has been reported to be both positively and negatively correlated with cancer progression and metastasis in the literature. To better understand how ALCAM might regulate cancer cell behavior, we utilized a panel of defined uveal melanoma cell lines with high or low ALCAM levels, and directly tested the effects of manipulating these levels on cell motility, invasiveness, and adhesion using multiple assays. ALCAM expression was stably silenced by shRNA knockdown in a high-ALCAM cell line (MUM-2B); the resulting cells displayed reduced motility in gap-closure assays and a reduction in invasiveness as measured by a transwell migration assay. Immunostaining revealed that the silenced cells were defective in the formation of adherens junctions, at which ALCAM colocalizes with N-cadherin and ß-catenin in native cells. Additionally, we stably overexpressed ALCAM in a low-ALCAM cell line (MUM-2C); intriguingly, these cells did not exhibit any increase in motility or invasiveness, indicating that ALCAM is necessary but not sufficient to promote metastasis-associated cell behaviors. In these ALCAM-overexpressing cells, however, recruitment of ß-catenin and N-cadherin to adherens junctions was enhanced. These data confirm a previously suggested role for ALCAM in the regulation of adherens junctions, and also suggest a mechanism by which ALCAM might differentially enhance or decrease invasiveness, depending on the type of cadherin adhesion complexes present in tissues surrounding the primary tumor, and on the cadherin status of the tumor cells themselves.

Chromosome 3 status in uveal melanoma: a comparison of fluorescence in situ hybridization and single-nucleotide polymorphism array

PURPOSE

To compare fluorescence in situ hybridization (FISH) using a centromeric probe for chromosome 3 (CEP3) and 3p26 locus-specific probe with single-nucleotide polymorphism array (SNP-A) analysis in the detection of high-risk uveal melanoma.

METHODS

Fifty cases of uveal melanoma (28 males, 22 females) treated by enucleation between 2004 and 2010 were analyzed. Fresh tissue was used for FISH and SNP-A analysis. FISH was performed using a CEP3 and a 3p26 locus-specific probe. Tumor size, location, and clinical outcome were recorded during the 7-year study period (median follow-up: 35.5 months; mean: 38.5 months). The sensitivity, specificity, positive predictive value, and negative predictive value were calculated.

RESULTS

Monosomy 3 was detected by FISH-CEP3 in 27 tumors (54%), FISH-3p26 deletion was found in 30 (60%), and SNP-A analysis identified 31 (62%) of the tumors with monosomy 3. Due to technical failures, FISH and SNP-A were noninterpretable in one case (2%) and two cases (4%), respectively. In both cases of SNP-A failure, tumors were positive for FISH 3p26 deletion and in a single case of FISH failure, monosomy 3 was found using SNP-A. No statistically significant differences were observed in any of the sensitivity or specificity measures.

CONCLUSIONS

For prediction of survival at 36 months, FISH CEP3, FISH 3p26, and SNP-A were comparable. A combination of prognostication techniques should be used in an unlikely event of technical failure (2%-4%).

Expression of 12 cytokines in aqueous humour of uveal melanoma before and after combined Ruthenium-106 brachytherapy and transpupillary thermotherapy

PURPOSE

To determine the aqueous humour levels of 12 cytokines in eyes with uveal melanoma and whether their expression changes after combined Ru-106 brachytherapy and transpupillary thermotherapy (TTT).

METHODS

Aqueous humour samples were collected from 20 patients with previously untreated uveal melanoma undergoing combined Ru-106 brachytherapy and TTT, both at the time of plaque placement and removal. Using multiplex biochip array technology, 12 different cytokines were measured, including interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, vascular endothelial growth factor (VEGF), tumour necrosis factor (TNF)-α, interferon (IFN)-γ, epidermal growth factor (EGF) and monocyte chemoattractant protein (MCP)-1. Aqueous humour from 20 patients undergoing cataract surgery was used as control.

RESULTS

IL-6, IL-8, IFN-γ and MCP-1 were highly expressed in uveal melanoma, whereas IL-2, IL-10 and TNF- α were low in expression. There was a positive correlation between tumour height and IL-8 level (p = 0.020). Vascular endothelial growth factor tends to be highly expressed in melanoma-containing eyes (p = 0.056). Levels of IL-6, IL-8 and IL-1β increased after the mean 117 ± 38 hrs of brachytherapy and adjunctive TTT with a tumour apex dose of 61 ± 28 Gy and a scleral contact dose of 786 ± 226 Gy. Increase in levels of IL-6 (p = 0.003) and IL-8 (p = 0.046) positively correlated with scleral contact dose.

CONCLUSIONS

Cytokines such as IL-6, IL-8, IFN-γ and MCP-1 may be implicated in the progression of uveal melanoma. Ocular irradiation from a Ru-106 plaque promoted an increase in the levels of IL-6, IL-8 and IL-1β, modulation of which could be useful in managing radiation-related side effects.

[Clinicopathological significance of expression of IGF-1R in uveal melanoma and its association with expression of p-AKT Thr308]

OBJECTIVE

To investigate the clinicopathological significance of expression of insulin-like growth factor-1 receptor (IGF-1R) and its association with the expression of p-AKT Thr308 in uveal melanoma.

METHODS

Experimental study. Twenty-four patients with uveal melanoma were included from January 2000 to December 2008. The levels of IGF-1R and p-AKT Thr308 were detected by immunohistochemical methods, and their association with clinicopathological parameters including localization of tumor, tumor size, largest tumor diameters, cell type, necrosis, degree of pigmentation, lymphocyte infiltration, mitosis rate, scleral invasion and liver metastasis were statistically analyzed. The relationship of expression of IGF-1R with clinicopathological parameters or with the expression of p-AKT Thr308 was analyzed by chi-square test.

RESULTS

The positive rate of expression of IGF-1R in 24 cases of uveal melanoma was 75%. The expression of IGF-1R were associated with the largest tumor diameters, degree of pigmentation, liver metastasis and lymphocyte infiltration (χ(2) = 15.569, P = 0.016; χ(2) = 11.348, P = 0.010; χ(2) = 8.738, P = 0.033; χ(2) = 8.362, P = 0.039). The positive rate of expression of p-AKT Thr308 was 58%. The expression of IGF-1R and p-AKT Thr308 was positively correlated (χ(2) = 17.108, P = 0.009).

CONCLUSION

IGF-1R plays a role in the development of uveal melanoma which may be induced by activation in PI3K/AKT pathway.

Germline BAP1 mutation predisposes to uveal melanoma, lung adenocarcinoma, meningioma, and other cancers

OBJECTIVE

To investigate the potential contribution of germline sequence alterations in the BAP1 gene in uveal melanoma (UM) patients with possible predisposition to hereditary cancer.

DESIGN

A total of 53 unrelated UM patients with high risk for hereditary cancer and five additional family members of one proband were studied. Mutational screening was carried out by direct sequencing.

RESULTS

Of the 53 UM patients studied, a single patient was identified with a germline BAP1 truncating mutation, c. 799 C→T (p.Q267X), which segregated in several family members and was associated with UM and other cancers. Biallelic inactivation of BAP1 and decreased BAP1 expression were identified in the UM, lung adenocarcinoma and meningioma tumours from three family members with this germline BAP1 mutation. Germline BAP1 variants of uncertain significance, likely non-pathogenic, were also identified in two additional UM patients.

CONCLUSION

This study reports a novel hereditary cancer syndrome caused by a germline BAP1 mutation that predisposes patients to UM, lung carcinoma, meningioma, and possibly other cancers. The results indicate that BAP1 is the candidate gene in only a small subset of hereditary UM, suggesting the contribution of other candidate genes.

Mesenchymal transition and dissemination of cancer cells is driven by myeloid-derived suppressor cells infiltrating the primary tumor

In order to metastasize, cancer cells need to acquire a motile phenotype. Previously, development of this phenotype was thought to rely on the acquisition of selected, random mutations and thus would occur late in cancer progression. However, recent studies show that cancer cells disseminate early, implying the existence of a different, faster route to the metastatic motile phenotype. Using a spontaneous murine model of melanoma, we show that a subset of bone marrow-derived immune cells (myeloid-derived suppressor cells or MDSC) preferentially infiltrates the primary tumor and actively promotes cancer cell dissemination by inducing epithelial-mesenchymal transition (EMT). CXCL5 is the main chemokine attracting MDSC to the primary tumor. In vitro assay using purified MDSC showed that TGF-β, EGF, and HGF signaling pathways are all used by MDSC to induce EMT in cancer cells. These findings explain how cancer cells acquire a motile phenotype so early and provide a mechanistic explanation for the long recognized link between inflammation and cancer progression.

Cancer progression has been depicted as a linear process, during which the incipient cancer cell sequentially accumulates mutations that confer the ability to metastasize. However, recent studies show that cancer cells disseminate early, before such mutations can accumulate, implying the existence of a different, faster route to the metastatic phenotype. Using a mouse model of melanoma, we show that the primary tumor attracts a subset of immune cells that actively promote cancer cell motility, dissemination, and metastasis. These tumor-infiltrating immune cells do so by reactivating a cellular program (mesenchymal transition) used by melanocytes during their development to colonize the skin, and also believed to be an essential step in cancer cell dissemination and metastasis. Once the melanoma cells migrate out of the primary tumor, they can lapse back to their original phenotype and lose their migratory potential. This transient phenotypic switch may accelerate carcinogenesis and participate in the plasticity of cancer. It explains how cancer cells might spread to other organs even before the original tumor is detected. In addition to the evidence gleaned from our mouse melanoma model, we show that these immune cells induce typical features of epithelial-mesechymal transition in both melanoma and bladder human cell lines when examined in culture dishes. These findings provide an underlying mechanism for the long-recognized link between inflammation and cancer progression.

Immunohistochemical assessment of mitotic count in uveal melanoma

BACKGROUND/AIMS

The mitotic count of uveal melanomas correlates with the risk of metastatic death, but with haematoxylin and eosin (H&E)-stained sections, it can be difficult to identify mitotic figures (MF) reliably. We investigated whether this measurement could be enhanced by immunohistochemistry, using the mitosis-specific marker Phospho-Histone H3 Ser10 (PHH3).

METHODS

Formalin-fixed, paraffin-embedded choroidal melanomas from patients treated by enucleation or trans-scleral local resection between 2006 and 2008 were used in this study. Sections from 132 tumours were stained with H&E and PHH3. Mitotic count was defined as the sum of MF counted in 40 high-power fields (HPF). In both H&E and PHH3-stained sections, mitotic count was determined independently by an experienced pathologist (SEC) and by a trainee ophthalmologist (MA). Data were assessed using the Kolmogorov-Smirnov (KS) statistical test and the Bland-Altman (BA) analysis.

RESULTS

The mitotic count determined by SEC in H&E and PHH3-stained sections had median values of 4/40 HPF and 8/40 HPF, respectively (KS, Z = 2.585 p < 0.001; BA, mean difference -5.95 [CI -22.15-10.22]), indicating poor reproducibility between these two methods. Similarly, the mean difference between the H&E and the PHH3 methods for calculating the mitotic count by MA was -7.03 (BA) [CI -23.38-9.31]. In contrast, the median mitotic counts determined by SEC & MA using PHH3 were 8/40 HPF and 9/40 HPF, respectively (KS, Z = 0.308 p = 1; BA, mean difference -0.29 [CI -2.65-2.06]), indicating good reproducibility between examiners.

CONCLUSIONS

MF were more easily identified following immunohistochemical staining with anti-PHH3. This resulted in higher mitotic counts than obtained with H&E sections. For PHH3, the mitotic count determined by a MA was virtually the same as those obtained by an experienced pathologist. PHH3 is now routinely used in our centre, and new prognostic thresholds for uveal melanoma will be defined in further studies.

Insulin-like growth factor system and sporadic malignant melanoma

Insulin and insulin-like growth factors (IGFs) are important regulators of energy metabolism and growth. Several findings have outlined an important role played by this family of molecules in both tumor maintenance and development. Despite the established contribution of the IGF system in carcinogenesis, little and contrasting data have been reported concerning the intertwined relationships between melanoma and this family of molecules. The present minireview aims to summarize the main topics and evidence concerning this malignant skin cancer, with a focus on the following: i) melanoma and cell proliferation effects induced by the IGF system, ii) in vitro and in vivo experimental data, and iii) targeting studies. Because of consistent findings regarding the role of the IGF-1 receptor in the modulation of IGF-1 activity, possible therapeutic strategies combining the use of antisense oligonucleotides against IGF-1 receptor mRNA could be applied in the future.

Intraocular lymphoma diagnosed by fine-needle aspiration biopsy

PURPOSE

To describe clinical experience in the diagnosis of intraocular lymphoma by fine-needle aspiration biopsy (FNAB) in patients with one or more discrete intraocular infiltrative lesions and limited or absent intravitreal tumour cells.

METHODS

 Retrospective descriptive analysis of patients who underwent intraocular FNAB of a solid retinal, subretinal pigment epithelial or uveal tumour that proved to be a malignant lymphoma.

RESULTS

After exclusions, our study group consisted of seven patients, each of whom had one or more discrete intraocular infiltrative lesions and limited or absent intravitreal tumour cells and underwent a diagnostic intraocular FNAB that confirmed malignant intraocular lymphoma cytopathologically. These included three patients with one or more geographic yellow subretinal pigment epithelial infiltrates and one patient each with a prominent nodular white subretinal pigment epithelial tumour, a rapidly developing solid placoid choroidal mass, a haemorrhagic retinal infiltrative lesion and an infiltrative iris tumour, respectively. A prominent feature of virtually all aspirates was a large proportion of degenerated lymphoid cells in the background. Cytologically intact tumour cells ranged from relatively homogeneous small round cells with large nucleus to cytoplasm ratio to pleomorphic large cells with irregular knob-like nuclear protrusions. Immunocytochemical stains for lymphoid markers were helpful in confirming the pathological diagnosis of lymphoma in the five patients in whom this testing was performed.

CONCLUSION

FNAB was a useful diagnostic tool in the described subgroup of patients with suspected intraocular lymphoma. FNAB should be considered as a diagnostic option in selected patients with suspected intraocular lymphoma, especially if there are few or no vitreous cells.

SPARC is expressed in human uveal melanoma and its abrogation reduces tumor cell proliferation

BACKGROUND

Secreted protein acidic and rich in cysteine (SPARC) has been shown to play an integral role in the progression of numerous malignancies. The aim of this study was to investigate the expression of SPARC in uveal melanoma (UM).

MATERIALS AND METHODS

SPARC expression was assessed in UM cell lines using RT-PCR and immunocytochemistry. Small interfering RNA directed against SPARC was used to transfect each of the cell lines, which were subsequently run in proliferation assays. SPARC expression was further investigated in 19 cases of human UM and 11 primary and 8 metastatic tumors from a rabbit xenograft model.

RESULTS

The cell lines transfected with SPARC siRNA showed a significant decrease in proliferation compared to controls. All cases of human uveal melanoma demonstrated positive staining for SPARC as did all primary and metastatic tumors from the xenograft model.

CONCLUSION

SPARC may represent a novel target to inhibit growth of UM.

KI-67 Immunopositivity in Choroidal and Ciliary Body Melanoma with Respect to Nucleolar Diameter and Other Prognostic Factors

PURPOSE

To study the association of cell proliferation in uveal melanoma with the mean of the 10 largest nucleoli (MLN), microvascular prognostic factors, and survival.

METHODS

Population-based, retrospective cohort study of 167 choroidal and ciliary body melanomas enucleated from 1972 to 1981. Mouse monoclonal antibody Ki-67 (clone 7B11) was used to identify proliferating cells. MLN was measured from silver stained slides. Kaplan-Meier and Cox regression analysis were performed.

RESULTS

The median number of Ki-67 immunopositive cells was 8 per tumor cross-section (range, 0-272) corresponding to a median of 0.30 cells/mm2. The percentage of immunopositive cells was 0.02% of all cells (range, 0-3.2). Tumors with epithelioid cells tended to have a higher percentage of immunopositive cells (p = 0.089). Ki-67 immunoreactivity, MLN, and presence of extravascular loops and networks were independent predictors of melanoma-related mortality, whereas Ki-67 immunoreactivity was not an independent predictor of mortality when presence of epithelioid cells was in the model.

CONCLUSIONS

Taken together with previous data, the results of this population-based study support the theory that high cell proliferation index is associated with presence of epithelioid cells and that presence of a high cell proliferation index is associated with a higher risk of metastatic death independent of MLN, microvascular density, and presence extravascular loops and networks.

Uveal melanoma and macular degeneration: molecular biology and potential therapeutic applications

Uveal melanoma is the most common primary intraocular malignant tumor in adults with 30% to 50% of patients that ultimately succumb to metastatic disease, mainly to the liver. (Shields et al. 1991) Although new diagnostic and therapeutic tools have been developed during the most recent years, only the eye conservation rate has been achieved, while the survival rate remains poor. The reason for this liver-homing is largely unknown, but it is conceivable that hepatic environmental factors may be implicated in the growth, dissemination, and progression of this malignancy. The insulin-like growth factor (IGF-1) that binds to the IGF-1 receptor (IGF-1R) is mainly produced in the liver. It has been shown to be crucial for tumor transformation, maintenance of malignant phenotype, promotion of cell growth, and prevention of apoptosis. (Baserga 1995) The hepatocyte growth factor/scatter factor (HGF/SF) is another growth factor produced in the liver and exerts its biological effects through binding to the plasma membrane receptor c-Met. The activation of this receptor by HGF/SF ligand can induce proliferation, motility, adhesion, and invasion of tumor cells. (Cruz et al. 2003) Metastasis is a process involving many components, including tumor cell adhesion, migration, extracellular matrix (ECM) proteolysis, and invasion. The tumor cells undergo intravasation, disperse via the vascular and the lymphatic systems, and finally extravasate to invade the secondary sites. In all these steps, proteolytic enzyme systems are involved, including the matrix metalloproteinase (MMP) system and the plasminogen activation system. The migration of a malignant cell through the ECM and the basement membrane requires proteolytic activities. (Stetler-Stevenson et al. 1993). Efforts to target the IGF-I system has been made with different types of cancer but not with uveal melanoma.

Receptors for the liver synthesized growth factors IGF-1 and HGF/SF in uveal melanoma: intercorrelation and prognostic implications

PURPOSE

Uveal melanoma disseminates preferentially to the liver. The mechanism for this homing is largely unknown, but growth factors synthesized in the liver may be involved. The present study was undertaken to investigate the possible relationship between cell surface receptors for two such growth factors: the c-Met proto-oncogene, which constitutes the receptor for hepatocyte growth factor/scatter factor (HGF/SF), and the insulin-like growth factor 1 receptor (IGF-1R). Their role as a prognostic factor was also clarified.

METHODS

Paraffin-embedded tumor specimens from 132 patients with primary uveal melanoma were analyzed by using well-established specific antibodies against c-Met and IGF-1R. The intercorrelation of receptor expression and association with melanoma-related survival of patients were determined by univariate and multivariate analyses.

RESULTS

Whereas the expression of both IGF-1R and c-Met was significantly associated with melanoma-specific mortality by univariate analysis (p = 0.004 and p = 0.007, respectively) only IGF-1R showed independent prognostic value by multivariate analysis, p = 0.004. The prognostic value of IGF-1R was stronger than such currently used prognostic parameters as tumor cell type and tumor diameter (p = 0.021 and p = 0.026, respectively). The expression patterns of the two growth factors receptors were weakly intercorrelated.

CONCLUSIONS

In conclusion, the data suggest that the receptors for IGF-1 and HGF/SF may play a role in the spread of uveal melanoma and its affinity to the liver. The strong correlation between IGF-1R expression and melanoma-specific mortality points to the use of IGF-1R as a prognostic tool [Economou MA, All-Ericsson C, Bykov V, Girnita L, Bartolazzi A, Larsson O & Seregard S (2005): Receptors for the liver synthesized growth factors IGF-1 and HGF/SF in uveal melanoma: intercorrelation and prognostic implications.

Oral picropodophyllin (PPP) is well tolerated in vivo and inhibits IGF-1R expression and growth of uveal melanoma

PURPOSE

The cyclolignan picropodophyllin (PPP) efficiently blocks the activity of insulin-like growth factor-1 receptor (IGF-1R) and inhibits growth of uveal melanoma cells in vitro and in vivo. In this study, we aimed to investigate the efficiency of orally administered PPP on growth of uveal melanoma xenografts. Further, we focused on the effect of PPP on vascular endothelial growth factor (VEGF) in vivo and evaluated its effects in combination with other established anti-tumor agents in vitro.

METHODS

Four different uveal melanoma cell lines (OCM-1, OCM-3, OCM-8, 92-1) were treated with PPP alone and in combination with imatinib mesylate, cisplatin, 5-FU and doxorubicin. Cell viability was determined by XTT assay. SCID mice xenografted with uveal melanoma cells were used to determine anti-tumor efficacy of oral PPP in vivo. Tumor samples obtained from the in vivo experiments were analyzed for VEGF and IGF-1R expression by western blotting.

RESULTS

PPP was found to be superior to the other anti-tumor agents in killing uveal melanoma cells. Oral PPP inhibited uveal melanoma growth in vivo and was well tolerated by the animals. PPP decreased VEGF expression in the tumors.

CONCLUSIONS

Oral PPP is well tolerated in vivo and caused total growth inhibition of uveal melanoma xenografts as well as it decreased the levels of VEGF in the tumors.

The insulin-like growth factor-I receptor inhibitor picropodophyllin causes tumor regression and attenuates mechanisms involved in invasion of uveal melanoma cells

PURPOSE

Uveal melanoma has a high mortality rate due to a high incidence of metastasis (up to 50%) which preferentially occurs in the liver. Conventional chemotherapy being the only therapeutic option today against metastatic uveal melanoma, has not proved to be effective. Therefore, new molecular targets important for malignant phenotype of uveal melanoma have to be found to design efficient pharmacologic agents.

EXPERIMENTAL DESIGN

We previously reported data indicating that the insulin-like growth factor-1 receptor (IGF-IR) is a metastasis predictor as well as a therapeutic target for uveal melanoma. In the present study, we made use of the cyclolignan picropodophyllin (PPP), which is an inhibitor of the IGF-IR.

RESULT

We showed that PPP efficiently block growth and viability of uveal melanoma cells in cultures and causes tumor regression in xenografted mice. In addition, treatment with PPP inhibited several mechanism involved in metastasis, including tumor cells adhesion to extracellular matrix proteins, activity and expression of matrix metalloproteinase 2, and cell migration as well as invasion through basement membranes and endothelial cell layer. Furthermore, PPP significantly delayed established of uveal melanoma tumor and drastically reduced the incidence of liver metastasis in mice.

CONCLUSIONS

Our data suggest that IGR-IR is crucial for growth and survival as well as invasion and metastasis of uveal melanoma cells. Targeting this receptor may therefore comprise a strategy to treat ongoing disease (today incurable) as well as a strategy to prevent development of metastases in patients with primary disease.

Melanoma associated spongiform scleropathy: characterization, biochemical and immunohistochemical studies

SUMMARY

Melanoma associated spongiform scleropathy (MASS) is a non-inflammatory scleral change with a spongiotic morphology seen in association with uveal melanoma. MASS is seen as whitish spindle shaped areas within the sclera that is adjacent to and in contact with a choroidal or ciliary body melanoma. This change can be seen as small scattered lesions in the inner scleral layers or as extensive areas along the whole extent of contact between the tumour and the sclera and involves most of the scleral thickness. MASS changes of different grades of severity were seen in 38% of 363 melanoma eyes investigated. The presence of MASS showed a statistical correlation with age. A significant high incidence of MASS was found in old age groups. This might due to the fact that MASS needs a longer period of contact between the tumour and the sclera to develop. It is also possible that age-related changes of the extracellular matrix might alter its response to melanoma produced factors leading to the development of MASS. The development of MASS and its severity are influenced by the extent of contact between the tumour and the sclera. This is supported by the significant statistical relation between the largest basal diameter of the tumours and the severity of MASS. Statistical correlation was found between MASS and scleral and extrascleral tumour extension. More than 90% of 82 specimens that showed tumour extension were associated with MASS. A biochemical analysis of scleral samples taken from areas with severe MASS showed a significant reduction of the main amino acids of collagen type I, which is the main scleral collagen. The amounts of total scleral proteins were significantly reduced. This scleral protein reduction is associated with an increase in glycosaminoglycans. These findings indicate a collagen degradation process. Immunohistochemical studies were performed to investigate the expression of matrix metalloproteinases (MMPs). In situ hybridization showed a significantly more frequent and more intense expression of MMP-2 by scleral fibroblasts in areas with MASS compared with areas without MASS. This was also seen by immunohistochemical staining. Similar high frequency and intense expression of MMP-2 were seen in tumour infiltrating macrophages. The results of biochemical and immunohistochemical studies indicate a collagen degradation process. This degradation may be the result of the proteolytic enzyme MMP-2 expressed by scleral fibroblasts under the effect of tumour humeral factors and/or tumour infiltrating macrophages. This scleral degradation results in fragmentation of the scleral collagen fibrils. This along with the accumulation of water in the sclera, as a result of the increase in the production of glycosaminoglycans, results in increase of scleral thickness in MASS areas and forms the histopathological picture of MASS. The scleral degradation may facilitate tumour invasion and may explain the statistical relation between MASS and scleral tumour invasion. MASS was found in a few of the eyes that had received pre-enucleation radiation. The possible explanation is that radiation might cause destruction of scleral fibroblasts reducing their ability to produce MMP-2, thus decreasing the development of MASS. No relation between MASS and survival was found. This is probably explained by the fact that the main cause of death due to uveal melanoma is distant metastasis. MASS changes are found to be associated with local tumour invasion but not statistically correlated to survival.