Hereditary uveal melanoma: a report of a germline mutation in BAP1.

Melanoma of the eye is a rare and distinct subtype of melanoma, which only rarely are familial. However, cases of uveal melanoma (UM) have been found in families with mixed cancer syndromes. Here, we describe a comprehensive search for inherited genetic variation in a family with multiple cases of UM but no aggregation of other cancer diagnoses. The proband is a woman diagnosed with UM at 16 years who within 6 months developed liver metastases. We also identified two older paternal relatives of the proband who had died from UM. We performed exome sequencing of germline DNA from members of the affected family. Exome-wide analysis identified a novel loss-of-function mutation in the BAP1 gene, previously suggested as a tumor suppressor. The mutation segregated with the UM phenotype in this family, and we detected a loss of the wild-type allele in the UM tumor of the proband, strongly supporting a causative association with UM. Screening of BAP1 germline mutations in families predisposed for UM may be used to identify individuals at increased risk of disease. Such individuals may then be enrolled in preventive programs and regular screenings to facilitate early detection and thereby improve prognosis.

Expression and prognostic significance of iNOS in uveal melanoma.

Uveal melanoma (UM) is the most common primary intraocular tumor in adults. Disease metastasis occurs in half of the patients and is uniformly fatal despite systemic therapy. Inducible nitric oxide synthase (iNOS) is associated with disease progression in various malignancies including cutaneous melanoma. In this retrospective cohort, we examined the prognostic value of iNOS in UM by performing immunohistochemistry on paraffin-embedded sections of primary tumors (90 patients) and matched primary and metastatic hepatic tumors (19 patients) with complete histopathological and clinical data. We show that iNOS is expressed in UM (57% of the patients) and high iNOS levels significantly (p = 0.04; hazard ratio (HR) = 2.3) predict disease-specific survival (DSS) as assessed by Kaplan-Meier analysis and univariate Cox's proportional hazards regression model. Furthermore, high iNOS expression in the UM primary tissue was significantly associated with metastatic disease and vice versa. Expression of iNOS in hepatic metastases significantly (p = 0.02) predicted a shortened survival as assessed by Kaplan-Meier analysis. However, iNOS did not appear to be a significant (p = 0.16; HR = 1.9) factor in the multivariate Cox's regression analysis performed together with the clinical parameters tumor diameter, tumor cell type, and tumor location in which only tumor diameter predicted DSS. In conclusion, iNOS predicts DSS in UM and may play a role in disease progression but it is not an independent prognostic factor.

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 insulinlike growth factor-1 receptor (IGF-1R) and inhibits the growth of uveal melanoma cells in vitro and in vivo. In this study, the authors investigated the efficiency of orally administered PPP on the growth of uveal melanoma xenografts. In addition, they focused on the effect of PPP on vascular endothelial growth factor (VEGF) in vivo and evaluated its effects in combination with other established antitumor 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-fluorouracil, and doxorubicin. Cell viability was determined by XTT assay. SCID mice that underwent xenografting with uveal melanoma cells were used to determine antitumor efficacy of oral PPP in vivo. Five mice were used per group. 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 antitumor agents in killing uveal melanoma cells in all four cell lines (IC50 < 0.05 microM). Oral PPP inhibited uveal melanoma growth in vivo in OCM-3 (P = 0.03) and OCM-8 (P = 0.01) xenografts and was well tolerated by the animals. PPP decreased VEGF expression in the OCM-1 (P = 0.006) and OCM-8 (P = 0.01) tumors. CONCLUSIONS: Oral PPP was well tolerated in vivo, caused total growth inhibition of uveal melanoma xenografts, and decreased VEGF levels in the tumors.

Inhibition of VEGF secretion and experimental choroidal neovascularization by picropodophyllin (PPP), an inhibitor of the insulin-like growth factor-1 receptor.

INTRODUCTION: Choroidal neovascularization (CNV) is a debilitating complication of age-related macular degeneration (AMD) and a leading cause of vision loss. Along with other angiogenic factors such as vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF)-1 and its receptor, IGF-1R, have been implicated in CNV. PURPOSE: A prior study has shown that the cyclolignan picropodophyllin (PPP) efficiently blocks the insulin-like growth factor-1 receptor (IGF-1R) activity and causes cell death in uveal melanoma cell lines and in an in vivo model. In this study we investigated the effect of PPP on VEGF expression, both in vitro and in vivo, and whether this effect has antiangiogenic consequences in a murine CNV model. METHODS: C57BL/6J mice with laser-induced CNVs were treated with PPP. Effects on CNV area were assayed by image analysis. VEGF levels in the choroid and retinal pigment epithelial cells (ARPE-19) were measured by Western blot or ELISA. Transcriptional activation of the VEGF promoter was determined by luciferase reporter gene assay. RESULTS: Mice treated with PPP, administered intraperitoneally or orally, showed a 22% to 32% (P = 0.002) decrease in CNV area. Furthermore, VEGF levels in the choroid were significantly reduced. In cultured ARPE-19 cells, IGF-1 was shown to increase VEGF secretion. This increase was completely blocked by PPP. PPP reduced the level of transcriptional activity of the VEGF promoter. CONCLUSIONS: PPP reduces IGF-1-dependent VEGF expression and CNV in vivo. Accordingly, IGF-1R inhibitors may be useful tools in the treatment of conditions associated with CNV, including neovascular AMD.

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. RESULTS: We showed that PPP efficiently blocks growth and viability of uveal melanoma cells in cultures and causes tumor regression in xenografted mice. In addition, treatment with PPP inhibited several mechanisms involved in metastasis, including tumor cell 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 layers. Furthermore, PPP significantly delayed establishment of uveal melanoma tumors and drastically reduced the incidence of liver metastasis in mice. CONCLUSIONS: Our data suggest that IGF-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.

Heterogeneity in retinoblastoma: a tale of molecules and models.

Retinoblastoma, an intraocular pediatric cancer, develops in the embryonic retina following biallelic loss of RB1. However, there is a wide range of genetic and epigenetic changes that can affect RB1 resulting in different clinical outcomes. In addition, other transformations, such as MYCN amplification, generate particularly aggressive tumors, which may or may not be RB1 independent. Recognizing the cellular characteristics required for tumor development, by identifying the elusive cell-of-origin for retinoblastoma, would help us understand the development of these tumors. In this review we summarize the heterogeneity reported in retinoblastoma on a molecular, cellular and tissue level. We also discuss the challenging heterogeneity in current retinoblastoma models and suggest future platforms that could contribute to improved understanding of tumor initiation, progression and metastasis in retinoblastoma, which may ultimately lead to more patient-specific treatments.

An international survey of classification and treatment choices for group D retinoblastoma.

AIM: To determine which IIRC scheme was used by retinoblastoma centers worldwide and the percentage of D eyes treated primarily with enucleation versus globe salvaging therapies as well as to correlate trends in treatment choice to IIRC version used and geographic region. METHODS: An anonymized electronic survey was offered to 115 physicians at 39 retinoblastoma centers worldwide asking about IIRC classification schemes and treatment patterns used between 2008 and 2012. Participants were asked to record which version of the IIRC was used for classification, how many group D eyes were diagnosed, and how many eyes were treated with enucleation versus globe salvaging therapies. Averages of eyes per treatment modality were calculated and stratified by both IIRC version and geographic region. Statistical significance was determined by Chi-square, ANOVA and Kruskal-Wallis tests using Prism. RESULTS: The survey was completed by 29% of physicians invited to participate. Totally 1807 D eyes were diagnosed. Regarding IIRC system, 27% of centers used the Children's Hospital of Los Angeles (CHLA) version, 33% used the Children's Oncology Group (COG) version, 23% used the Philadelphia version, and 17% were unsure. The rate for primary enucleation varied between 0 and 100% and the mean was 29%. By IIRC version, primary enucleation rates were: Philadelphia, 8%; COG, 34%; and CHLA, 37%. By geographic region, primary enucleation rates were: Latin America, 57%; Asia, 40%; Europe, 36%; Africa, 10%, US, 8%; and Middle East, 8%. However, systemic chemoreduction was used more often than enucleation in all regions except Latin America with a mean of 57% per center (P<0.0001). CONCLUSION: Worldwide there is no consensus on which IIRC version is used, systemic chemoreduction was the most frequently used initial treatment during the study period followed by enucleation and primary treatment modality, especially enucleation, varied greatly with regards to IIRC version used and geographic region.

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.

Choroidal biopsies for intraocular tumors of indeterminate origin.

PURPOSE: To evaluate the role of pars plana vitrectomy-assisted incisional biopsies in the management of choroidal tumors of unclear origin. DESIGN: Retrospective, noncomparative, consecutive interventional case series. METHODS: Ten consecutive patients with indeterminate choroidal tumors underwent a standardized three-port pars-plana vitrectomy-assisted subretinal biopsy using a bimanual approach with standard intraocular forceps and a diamond knife. Specimens were fixed in formaldehyde embedded in paraffin and further subjected to histopathological and immunohistochemical analyses. RESULTS: A histologic diagnosis was obtained in all (10 of 10) cases including choroidal melanoma (five of 10), metastasis (two of 10), subretinal hemorrhage (two of 10), and nodular scleritis (one of 10). Five eyes were enucleated as a result of the histologic diagnosis. Three cases of postoperative complications were seen in three patients (newly formed rhegmatogenous retinal detachment, increased serous retinal detachment, and vitreous hemorrhage). No cases of intra- or extraocular tumor spread were detected through follow-up periods ranging from 3 to 29 months. CONCLUSIONS: Pars plana vitrectomy-assisted incisional biopsy is a valuable diagnostic procedure for cases of choroidal tumors of unknown origin in selected patients. However, the relatively high frequency of postoperative complications noted in the present study and the potential risk of dissemination of tumor cells underscores the importance of rigorous case selection.

Insulin-like growth factor-1 receptor in uveal melanoma: a predictor for metastatic disease and a potential therapeutic target.

PURPOSE: To investigate the expression of the insulin-like growth factor-1 receptor (IGF-1R) with special focus on its role in cell growth in uveal melanoma. METHODS: Paraffin material from 36 clinicopathologically well characterized cases of primary uveal melanomas (18 of which had metastasized to the liver) with more than 15 years' follow-up was used for immunohistochemical analysis. In the experimental studies, three uveal melanoma cell lines (OCM-1, OCM-3, and 92-1) were used. The expression level of IGF-1R in the cell lines was modulated by glycosylation inhibitors, and the IGF-1R was neutralized with the antibody alphaIR-3. Expression of IGF-1R was assayed by Western blot analysis and immunohistochemistry. Cell growth and survival were analyzed by cell counting, thymidine incorporation, and viability assays. RESULTS: Western blot analysis and immunohistochemistry confirmed that IGF-1R is expressed in uveal melanoma. Although 10 of 18 patients who died of metastasizing disease showed high IGF-1R expression, only 5 of 18 tumors from patients who survived for 15 years or more after enucleation exhibited a high IGF-1R expression. Kaplan-Meier analysis showed a significant association (P = 0.035) between a high IGF-1R expression and death due to metastatic uveal melanoma. Using in vitro experimental models, we found that inhibition of the IGF-1R activity (tyrosine phosphorylation) was associated with a drastic decrease in uveal melanoma cell viability. CONCLUSIONS: These data suggest an important role of IGF-1R in uveal melanoma. The significant association between high IGF-1R expression and death due to metastatic disease may be explained by the fact that IGF-1 is mainly produced in the liver, which is the preferential site for uveal melanoma metastases. These data also point to the possibility of therapeutically interfering with IGF-1R, which appears to be expressed preferentially in uveal melanomas that appear to follow an aggressive clinical course.

c-Kit-dependent growth of uveal melanoma cells: a potential therapeutic target?

PURPOSE: This study was conducted to investigate the expression and functional impact of the proto-oncogene c-kit in uveal melanoma. METHODS: Based on immunohistochemical (IHC) study of paraffin-embedded specimens from 134 uveal melanomas and Western blot analysis on eight fresh-frozen samples the expression of c-kit in uveal melanoma was studied. Furthermore, the phosphorylation of c-kit and the impact of the tyrosine kinase inhibitor STI571 was examined in the three uveal melanoma cell lines OCM-1, OCM-3, and 92-1. RESULTS: Eighty-four of 134 paraffin-embedded samples and six of eight fresh-frozen samples expressed c-kit. c-Kit was strongly expressed and tyrosine phosphorylated in cultured uveal melanoma cells compared with cutaneous melanoma cells. Moreover, in contrast to cutaneous melanoma cell lines c-kit maintained a high phosphorylation level in serum-depleted uveal melanoma cells. No activation-related mutations in exon 11 of the KIT gene were found. On the contrary, expression of the stem cell growth factor (c-kit ligand) was detected in all three uveal melanoma cell lines, suggesting the presence of autocrine (paracrine) stimulation pathways. Treatment of uveal melanoma cell lines with STI571, which blocks c-kit autophosphorylation, resulted in cell death. The IC(50) of the inhibitory effects on c-kit phosphorylation and cell proliferation was of equal size and less than 2.5 microM. CONCLUSIONS: The results confirm that c-kit is vastly expressed in uveal melanoma, suggest that the c-kit molecular pathway may be important in uveal melanoma growth, and point to its use as a target for therapy with STI571.

The heterogenic final cell cycle of chicken retinal Lim1 horizontal cells is not regulated by the DNA damage response pathway.

Cells with aberrations in chromosomal ploidy are normally removed by apoptosis. However, aneuploid neurons have been shown to remain functional and active both in the cortex and in the retina. Lim1 horizontal progenitor cells in the chicken retina have a heterogenic final cell cycle, producing some cells that enter S-phase without proceeding into M-phase. The cells become heteroploid but do not undergo developmental cell death. This prompted us to investigate if the final cell cycle of these cells is under the regulation of an active DNA damage response. Our results show that the DNA damage response pathway, including γ-H2AX and Rad51 foci, is not triggered during any phase of the different final cell cycles of horizontal progenitor cells. However, chemically inducing DNA adducts or double-strand breaks in Lim1 horizontal progenitor cells activated the DNA damage response pathway, showing that the cells are capable of a functional response to DNA damage. Moreover, manipulation of the DNA damage response pathway during the final cell cycle using inhibitors of ATM/ATR, Chk1/2, and p38MAPK, neither induced apoptosis nor mitosis in the Lim1 horizontal progenitor cells. We conclude that the DNA damage response pathway is functional in the Lim1 horizontal progenitor cells, but that it is not directly involved in the regulation of the final cell cycle that gives rise to the heteroploid horizontal cell population.

A 10-year experience of outcome in chemotherapy-treated hereditary retinoblastoma.

PURPOSE: The aim is to report the 10-year retrospective experience of systemic chemotherapy for a population-based group of patients with hereditary retinoblastoma at a national referral centre. The outcomes include control rates, treatment side-effects, adjuvant therapy, failure rate, survival, secondary cancers and visual acuity. METHODS: All patients (n = 24, 46 eyes) diagnosed with retinoblastoma and treated with systemic chemotherapy at a national referral centre during 2001-2011 were included. Data were extracted from medical records. RESULTS: The patients were followed for a mean of 60 months (range 13-144). Four-six cycles of VEC was administered to all newly diagnosed group B/C/D/E eyes with bilateral disease and 83% (38 of 46) responded to the treatment. None of the patients discontinued chemotherapy because of adverse reactions. Altogether 26% (12 of 46) of the eyes received second-line therapy (other than thermotherapy, cryotherapy and chemotherapy). The failure rate was 35% (16 of 46) and mortality rate 0%. None of the patients developed CNS manifestations (metastases or trilateral retinoblastoma). One of the patients developed a second primary tumour (osteosarcoma) 4 years following retinoblastoma diagnosis. Altogether 17% (4 of 24) patients received radiation therapy, 28% (13 of 46) of the eyes had to be enucleated, and one patient underwent bilateral enucleation. The age-correlated visual acuity was mean of 73% of expected visual acuity. CONCLUSION: Group A/B retinoblastomas have a distinct chemotherapy response, while group C/D/E tumours do not respond as well. The success rate was 65%; while patients have a good prognosis for life, approximately one-third of all hereditary cases received radiation therapy or underwent enucleation.

The terminal basal mitosis of chicken retinal Lim1 horizontal cells is not sensitive to cisplatin-induced cell cycle arrest.

For proper development, cells need to coordinate proliferation and cell cycle-exit. This is mediated by a cascade of proteins making sure that each phase of the cell cycle is controlled before the initiation of the next. Retinal progenitor cells divide during the process of interkinetic nuclear migration, where they undergo S-phase on the basal side, followed by mitoses on the apical side of the neuroepithelium. The final cell cycle of chicken retinal horizontal cells (HCs) is an exception to this general cell cycle behavior. Lim1 expressing (+) horizontal progenitor cells (HPCs) have a heterogenic final cell cycle, with some cells undergoing a terminal mitosis on the basal side of the retina. The results in this study show that this terminal basal mitosis of Lim1+ HPCs is not dependent on Chk1/2 for its regulation compared to retinal cells undergoing interkinetic nuclear migration. Neither activating nor blocking Chk1 had an effect on the basal mitosis of Lim1+ HPCs. Furthermore, the Lim1+ HPCs were not sensitive to cisplatin-induced DNA damage and were able to continue into mitosis in the presence of γ-H2AX without activation of caspase-3. However, Nutlin3a-induced expression of p21 did reduce the mitoses, suggesting the presence of a functional p53/p21 response in HPCs. In contrast, the apical mitoses were blocked upon activation of either Chk1/2 or p21, indicating the importance of these proteins during the process of interkinetic nuclear migration. Inhibiting Cdk1 blocked M-phase transition both for apical and basal mitoses. This confirmed that the cyclin B1-Cdk1 complex was active and functional during the basal mitosis of Lim1+ HPCs. The regulation of the final cell cycle of Lim1+ HPCs is of particular interest since it has been shown that the HCs are able to sustain persistent DNA damage, remain in the cell cycle for an extended period of time and, consequently, survive for months.

Intratumoral forkhead box P3-positive regulatory T cells predict poor survival in cyclooxygenase-2-positive uveal melanoma.

BACKGROUND: Forkhead box P3 (FOXP3)-positive regulatory T cells (Tregs) are key mediators of peripheral tolerance and suppress efficient antitumor responses. Prostaglandin E(2) (PGE(2)) produced by inducible cyclooxygenase-2 (COX-2) can lead to Treg induction. COX-2 expression has been linked to tumorigenesis and growth in various malignancies. The objective of the current study was to investigate whether Tregs infiltrate uveal melanomas (UMs) and whether their prevalence is linked to COX-2 expression and the prediction of overall survival (OS). METHODS: One hundred patients who underwent enucleation after they were diagnosed with UM were included in the study. Immunohistochemical staining with monoclonal anti-FOXP3, anti-CD4, and anti-COX-2 antibodies was performed, and immunoreactivity was assessed. Correlations of COX-2 expression with the presence of Tregs, established clinicopathologic parameters, and OS were evaluated in univariate and multivariate analyses. RESULTS: High expression of COX-2 was predictive of shortened OS. FOXP3-positive Tregs were detectable in 24% of UMs and were restricted to malignant tissue. The extent of COX-2 expression was associated significantly with Treg prevalence (P = .004) and Treg intratumoral localization (P = .005). Intratumoral Tregs (but not the prevalence of Tregs) were independent marker for worse OS with a hazard ratio of 5.36 in patients with COX-2-positive tumors. CONCLUSIONS: The current results demonstrated that high COX-2 expression is associated with OS and Treg prevalence in UM. These findings are in line with the observations that COX-2/PGE(2) induces Tregs and that Tregs may alter antitumor responses, resulting in a negative effect on the clinical disease course. Intratumoral Tregs are an independent prognostic marker for COX-2-positive UM, and these results put COX-2 inhibitors and Treg depletion into the spotlight of potential novel treatment modalities for patients with UM.

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.

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.

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.

Inhibition of VEGF secretion and experimental choroidal neovascularization by picropodophyllin (PPP), an inhibitor of the insulin-like growth factor-1 receptor.

INTRODUCTION: Choroidal neovascularization (CNV) is a debilitating complication of age-related macular degeneration (AMD) and a leading cause of vision loss. Along with other angiogenic factors like vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF-1) and its receptor, IGF-1R, have been implicated in CNV. PURPOSE: We have previously shown that the cyclolignan picropodophyllin (PPP) efficiently blocks the insulin-like growth factor-1 receptor (IGF-1R) activity and causes cell death in uveal melanoma cell lines and in an in-vivo model. In this study we investigated the effect of PPP on VEGF expression both in vitro and in vivo and whether this effect has anti-angiogenic consequences in a murine CNV model. MATERIALS AND METHODS: C57BL/6J mice with laser-induced CNVs were treated with PPP. Effects on CNV area were assayed by image analysis. VEGF levels in choroids and retinal pigment epithelial cells (APRE-19) were measured by Western blot or ELISA. Transcriptional activation of the VEGF promoter was determined by luciferase reporter gene assay. RESULTS: Mice treated with PPP, administered intraperitoneally or orally, showed 22-32% (p = 0.002) decrease in CNV area. Furthermore, VEGF levels in the choroids were significantly reduced. In cultured APRE-19 cells, IGF-1 was shown to increase VEGF secretion. This increase was completely blocked by PPP. We could confirm that PPP reduced the level of transcriptional activity of VEGF promoter. CONCLUSIONS: PPP reduces IGF-1 dependent VEGF expression and CNV in vivo. Accordingly, IGF-1R inhibitors may be useful tools in the therapy of conditions associated with CNV including neovascular AMD.