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.     

Cripto-1 expression in uveal melanoma: an immunohistochemical study

Human Cripto, the founder member of the epidermal growth factor-Cripto-FRL1-Cryptic (EGF-CFC) family, plays an important role during early embryonic development and in particular in carcinogenesis and the development of cancer metastases. Cripto-1 is over-expressed in most cancers, but is absent or only weakly expressed in normal cells. For this reason, Cripto-1 could be of potential value in the targeted treatment. There is no information on the expression of Cripto-1 in human uveal melanoma. Cripto-1 reactivity was evaluated by immunohistochemistry on 36 archival uveal melanomas using the polyclonal antibody to Cripto-1. The tumors were divided in to 2 groups. There were 18 uveal melanomas with no intrascleral or extrascleral extension and 18 uveal melanomas with intrascleral/extrascleral extension/liver metastasis. Cripto-1 reactivity was correlated with tumor aggressiveness and cell type. Furthermore, we studied the immunolocalization of Cripto-1 in 4 uveal melanoma cell lines OCM-1, OCM-8, and 92-1, and OMM-1 and in 2 primary uveal melanocyte cultures. Cripto-1 was expressed in both the non-invasive and aggressive uveal melanomas. Cripto-1 was positive in the 4 uveal melanoma cell lines and absent in the primary uveal melanocyte cultures. Retinal tissue did not express Cripto-1. The results suggest that Cripto-1 is expressed in uveal melanoma, negative in the non-neoplastic ocular tissue and point to its use as a target for therapy.     

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.     

PD-L1: PD-1 interaction contributes to the functional suppression of T-cell responses to human uveal melanoma cells in vitro

PURPOSE: To assess the expression of PD-L1 on human uveal melanomas and its potential to suppress T-cell function. METHODS: A panel of primary and metastatic uveal melanoma cell lines was evaluated for PD-L1 expression by RT-PCR and flow cytometric analysis. Uveal melanoma-containing eyes were examined for PD-L1 expression by immunohistochemistry. PD-L1 function was tested by coculturing IFN-gamma-pretreated uveal melanoma cells with activated Jurkat T cells for 48 hours and assessing T-cell production of IL-2 by ELISA. RESULTS: Five of the nine primary and one of the five metastatic uveal melanoma cell lines tested constitutively expressed PD-L1 protein at various levels. However, all primary and metastatic uveal melanoma cell lines upregulated PD-L1 expression after stimulation with IFN-gamma. Immunohistochemistry demonstrated that PD-L1 was not expressed by primary uveal melanomas in situ. IL-2 production by activated Jurkat T cells was decreased significantly when the cells were cocultured with IFN-gamma-pretreated uveal melanoma cells. More than 70% of IL-2 production was restored by addition of either anti-PD-L1 or anti-PD-1 antibody to the coculture assays (P < 0.01). CONCLUSIONS: Expression of PD-L1 by uveal melanoma cells regulates T-cell function by suppressing IL-2 production. The results imply that the presence of IFN-gamma in the tumor local microenvironment promotes upregulation of PD-L1 expression by uveal melanoma, which may, in part, promote immune escape by impairing T-cell function. The selective blockade of PD-L1 is a potential strategy in T-cell-based immunotherapy for uveal melanoma.     

In vitro targeting of NG2 antigen by 213Bi-9.2.27 alpha-immunoconjugate induces cytotoxicity in human uveal melanoma cells

PURPOSE: To examine uveal melanoma cell lines for the expression of human melanoma proteoglycan (NG2) using monoclonal antibody (mAb) 9.2.27 and subsequently to assess the in vitro specificity and cytotoxicity of mAb 9.2.27 conjugated to the alpha-particle-emitting radioisotope 213bismuth (213Bi-9.2.27) for uveal melanoma cells. METHODS: Immunocytochemistry and flow cytometry were used to examine OCM-1, OCM-3, OCM-8, OMM-1, Mel202 and 92-1 melanoma cell lines for NG2 expression. Melanoma cells were treated with test (213Bi-9.2.27) or control (213Bi-A2) alpha-immunoconjugates (AICs). The specific cytotoxicity of 213Bi-9.2.27 AIC was evaluated using an MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfenyl)-2H-tetrazolium, inner salt) assay. Cell death was also assessed using TUNEL. RESULTS: OCM-1, OCM-8, OMM-1, and Mel202 cells strongly expressed NG2. OCM-3 cells showed moderate expression and 92-1 cells were NG2-negative. 213Bi-9.2.27 specifically killed NG2-positive OCM-1, OCM-8, and OMM-1 cells in a concentration-dependent manner. D0 values for 37% cell survival of NG2-positive OCM-1, OCM-8, and OMM-1 cells were 5.8, 5.0, and 5.6 microCi, respectively, and the value was 43.4 muCi for NG2-negative 92-1 cells. CONCLUSIONS: The specific cytotoxicity of 213Bi-9.2.27 AIC for NG2-positive, but not NG2-negative, cells suggests NG2 is a suitable target for alpha-immunotherapy in uveal melanoma. 213Bi-9.2.27 AIC used directly or as adjunct therapy may be a promising new agent for treating NG2-positive uveal melanomas or metastases.     

Establishment and characterization of two uveal melanoma cell lines derived from tumors with loss of one chromosome 3

Uveal melanoma (UM) is the most common intraocular malignancy. Approximately 50% of UM patients die of metastases, which mainly arise from primary tumors with loss of an entire chromosome 3 (monosomy 3). To identify cell lines with monosomy 3 that may serve as a model system for UM with high metastatic potential, we determined the chromosome 3 status of previously established and frequently used UM cell lines by microsatellite analysis (Mel202, Mel285, Mel290, 92-1, OMM-1, OCM-1, OCM-3, OCM-8) and cytogenetic analysis (Mel202, Mel285, OCM-8). We found that none of these cell lines has monosomy 3. Therefore we established and characterized two novel cell lines, UPMM-1 and UPMM-2 that are both developed from primary uveal melanoma tissue samples with monosomy 3. The cell line UPMM-1 has retained the chromosome 3 status of the primary tumor. In UPMM-2 chromosome 3 has undergone duplication (isodisomy) and is present on the background of a hypotetraploid karyotype. Our data suggest that, UPMM-1 may serve as a model system to study the mechanisms underlying the metastatic potential of uveal melanomas with monosomy 3.     

胰岛素样生长因子1受体（IGF-1R）基因表达对脉络膜黑色素瘤细胞增殖、凋亡及STAT3信号通路的调控作用

目的　探讨胰岛素样生长因子1受体（insulin-like growth factor 1 receptor，IGF-1R）基因表达对脉络膜黑色素瘤（choroidal melanoma，CM）细胞增殖、凋亡及STAT3信号通路的调控作用。方法　参照Lipofectamine^TM2000说明将干扰IGF-1R表达的siRNA转染人CM细胞OCM-1作为IGF-1R-siRNA组，并设置无干扰作用的siRNA及加入脂质体的细胞作为阴性对照组和空白对照组，AG490作为STAT3信号通路抑制剂，收集转染48 h的细胞，通过CCK8法及流式细胞仪分别检测细胞活力及细胞凋亡率；Western blot检测STAT3信号通路磷酸化的p-JAK2和p-STAT3及下游靶基因Cyclin D1和Bcl-xL的表达。结果　阴性对照组IGF-1R表达量（0.243±0.036）与空白对照组（0.228±0.030）差异无统计学意义（P>0.05），IGF-1R-siRNA组IGF-1R表达量（0.071±0.010）低于空白对照组，差异有统计学意义（P<0.05）。IGF-1R-siRNA转染的OCM-1细胞IGF-1R的表达明显降低；与空白对照组比较，IGF-1R-siRNA组细胞活力显著降低，细胞凋亡率显著升高（均为P<0.05）。IGF-1R-siRNA组p-JAK2、p-STAT3、Cyclin D1和Bcl-xL的蛋白表达均低于空白对照组，差异均有统计学意义（均为P<0.05）。IGF-1R-siRNA+AG490组细胞活力低于IGF-1R-siRNA组，细胞凋亡率高于IGF-1R-siRNA组，差异均有统计学意义（均为P<0.05）。IGF-1R-siRNA组p-JAK2、p-STAT3、Cyclin D1和Bcl-xL的蛋白表达均高于IGF-1R-siRNA+AG490组，差异均有统计学意义（均为P<0.05）。结论　下调 IGF-1R基因表达可通过抑制STAT3信号通路降低CM细胞增殖并诱导细胞凋亡。     

胰岛素样生长因子-1受体在原发性葡萄膜恶性黑色素瘤中的表达及临床意义

目的 观察胰岛素样生长因子-1受体(insulin-like growth factor-1-receptor,IGF-1R)对人葡萄膜恶性黑色素瘤预后评估的作用.方法 用免疫组织化学SABC法检测IGF-1R在41例葡萄膜恶性黑色素瘤组织的表达.用x2检验分析其表达与临床病理参数之间的关系.采用乘积极限法分析生存率,并绘制Kaplan-Meier曲线.建立Cox比例风险模型,探讨影响预后的相关危险因素.结果 41例葡萄膜恶性黑色素瘤标本中,IGF-1R在28例肿瘤的细胞胞浆中表达,阳性率68.3%.x2检验分析显示:IGF-1R的表达水平与肿瘤的细胞类型、最大基底直径、肿瘤的高度显著相关(P<0.05).单因素及多因素分析提示:IGF-1R的表达为影响预后的因素.结论 IGF-1R在葡萄膜恶性黑色素瘤中的高表达是影响预后的因素,可能成为临床判断预后和指导治疗的重要指标.     

Heat shock protein expression in the eye and in uveal melanoma

PURPOSE: Expression of heat shock proteins (HSPs) is of prognostic significance in several tumor types, whereas HSPs may also have clinical use as stimulators in tumor vaccination. HSP expression levels were determined in normal eyes and in uveal melanoma and tested whether HSPs expression was associated with prognostic parameters in the uveal melanoma. METHODS: Expression of HSP27, HSP70, HSP90, and glycoprotein96 (GP96) were determined on paraffin-embedded and frozen sections from seven healthy eyes, 20 primary uveal melanomas without prior treatment, and 18 uveal melanomas after prior treatment. HSP expression was determined by alkaline phosphatase-anti-alkaline phosphatase (APAAP) immunohistochemistry, using appropriate monoclonal antibodies and scored semiquantitatively. Expression of HSPs was validated on retinal tissue of a normal eye and in two uveal melanoma cell lines by Western blot analysis. RESULTS: Expression of HSPs was observed in epithelial and pigment cells of the normal eyes. In uveal melanoma, the level of expression of HSPs varied. Expression of HSP27 and GP96 was noted in more than 30 of 38 uveal melanomas (with, respectively, a mean of 66% and 53% positive cells). HSP70 and HSP90 were expressed in 6% of tumor cells. The amount of expression of any of the HSP types was not significantly associated with known prognostic factors. There was not a significant difference in expression of the HSPs between uveal melanomas with or without any type of prior treatment. CONCLUSIONS: In this study, expression of HSPs in uveal melanoma is not correlated with known histopathologic prognostic factors. The high expression of GP96 indicates that this protein is a potential vector in tumor vaccination in patients with large uveal melanomas.     

Melanocortin 1 receptor is expressed by uveal malignant melanoma and can be considered a new target for diagnosis and immunotherapy

PURPOSE: Uveal melanoma is the most common primary malignant ocular cancer in adults. This tumor has a distinct expression pattern of markers compared with cutaneous melanoma. MC1R is under study as a potential target for antitumor immunity. Because of the potential immunogenicity of MC1R, it is important to evaluate its expression on uveal melanomas. METHODS: Two novel monoclonal antibodies (MP1.1C11 and MP1.1B7) were used to examine the expression of MC1R in uveal melanomas. Tissue samples obtained from 17 patients were analyzed for expression of MC1R by immunohistochemistry. Additionally, uveal melanoma cell lines were treated with proinflammatory cytokines, after which MC1R cell surface expression was analyzed by flow cytometry. RESULTS: Results demonstrated that MC1R is expressed by uveal melanoma to a significantly greater extent than other melanoma markers. With the use of MP1.1C11 or MP1.1B7, MC1R was detected in 95% of the tested melanoma tissues, including one liver metastasis. In contrast, MART-1, S100-specific protein, and gp-100 were only expressed by 66%, 33%, and 67% of the analyzed samples, respectively. Results also demonstrated that even though MC1R is mainly located intracellularly, its cell surface expression can be promoted by cytokines such as IFN-gamma, TNF-alpha, IL-4, and IL-10. CONCLUSIONS: These observations support the inclusion of MC1R in the panel of markers for the diagnosis of uveal melanoma. Therapeutic use of MC1R-specific antibodies targeting cytokine-induced MC1R potentially requires expression of the target molecule on the surfaces of tumor cells. Data presented here support MC1R as a new marker and a putative therapeutic target for uveal melanoma.     

Whole-body bioluminescent imaging of human uveal melanoma in a new mouse model of local tumor growth and metastasis

PURPOSE: Human uveal melanoma develops in one of the most capillary-rich tissues of the body and has a pure hematogenous dissemination. Radiodiagnostic examinations, such as ultrasonic diagnostic resonance imaging and chest radiographs plus liver enzyme studies in blood, are methods used to detect liver and other distant metastases in patients. Nevertheless, the mortality rate is high, because of the frequent occurrence of metastases and the lack of systemic therapy. Therefore, the development of novel anticancer strategies is urgent, and more sensitive and less invasive methods of detecting and monitoring in vivo tumor growth and metastatic disease in cancer models are needed. METHODS: A luciferase (Luc)-positive human uveal melanoma cell line (OCM-1 FRT/luc) was established. Tumor cells were inoculated into the anterior chamber of murine eyes for induction of orthotopic growth or into the left heart ventricle to mimic hematogenous micrometastatic spread. Development of metastases and tumor growth was monitored weekly by whole-body bioluminescent reporter imaging (BLI). RESULTS: Injection of cancer cells into the anterior chamber of the eye of mice closely mimicked orthotopic tumor growth of uveal melanoma. Tumor progression could be quantitatively monitored 3 weeks after inoculation of 10(5) OCM-1 FRT/luc cells. Of the mice injected, 83% exhibited a detectable tumor within 5 weeks. Intracardiac injection of tumor cells resulted in metastatic growth, especially in bone. Mice had bone (maxillofacial region and femora) and visceral (lung and mediastinum) metastases after 4 to 6 weeks. OCM-1 FRT/luc cells may also have a propensity to colonize the eye after intracardiac inoculation. CONCLUSIONS: BLI enables continuous quantitative monitoring in the same animal of growth kinetics for each tumor and its metastases. This model will accelerate the understanding of the pathogenesis and treatment of uveal melanoma and metastasis.     

HLA-I-Antigenexpression korreliert mit dem histologischen Zelltyp uvealer Melanome

PURPOSE: The prognosis of uveal melanoma is correlated with its histologic cell type. The epithelioid cell type is associated with a higher metastatic rate than the spindle cell type. The Human Leucocyte Antigen Class I (HLA-I) expression of the melanoma also correlates with the prognosis. In this study, we analyzed HLA-I antigen expression of uveal melanomas to determine whether a relationship exist between antigenic expression and melanoma cell type. METHODS: Formalin-fixed, paraffin-embedded spindle cell type (n = 11) and epithelioid cell type (n = 11) uveal melanomas were immunostained with the HC10 antibody (1:80) for HLA-I antigen expression with appropriate positive and negative controls. Sections were assessed semiquantitatively according to the percentage of stained cells. RESULTS: Among the spindle cell type melanomas, 2 out of 11 (18%) stained with HC10 antibodies. The staining intensity was less than 25% of the cells in these two melanomas. Among the epithelioid cell type melanomas, 9 out of 11 (82%) stained with HC10. The staining intensity was more than 25% of the cells in 5 of these 9 melanomas. CONCLUSIONS: It is unknown why spindle and epithelioid cell type uveal melanomas have different prognoses. Human uveal melanoma cell lines with low HLA-I expression are susceptible to NK cell-mediated lysis in vitro and in murine studies. The prognostically more favorable spindle cell type melanoma expresses less HLA-I than the epithelioid cell type melanoma. These results stress the role of NK cells in the rejection of 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.     

Osteopontin expression and serum levels in metastatic uveal melanoma: a pilot study

PURPOSE: This was a pilot study conducted to examine the expression of osteopontin in uveal melanoma and to determine whether serum osteopontin can be used in detecting metastatic uveal melanoma. METHODS: Osteopontin mRNA was measured in three uveal melanoma cell lines of various invasive potential by real-time PCR. Tissue sections of primary and metastatic uveal melanomas were stained for osteopontin. Serum osteopontin levels were measured by ELISA assays in 15 patients with metastatic uveal melanoma and in 37 patients who were disease-free for at least 10 years after treatment of the primary tumor. Paired serum samples drawn from eight patients before and after development of metastasis were analyzed. RESULTS: By real-time PCR, highly invasive primary and metastatic uveal melanoma cells expressed 6- and 250-fold excess osteopontin mRNA, respectively, compared with poorly invasive primary uveal melanoma cells. Tissue sections of primary uveal melanomas lacking looping vasculogenic mimicry patterns either did not stain for osteopontin or exhibited weak, diffuse staining. In primary melanomas containing looping vasculogenic mimicry patterns, strong osteopontin staining was detected in the tumor periphery where patterns were located. Diffuse strong expression of osteopontin was detected in eight samples of uveal melanomas metastatic to the liver. Serum osteopontin levels were significantly higher in patients with metastatic uveal melanoma than in patients who had been disease free for at least 10 years after treatment (P = 0.0001) or in age-matched control subjects. Serum osteopontin levels were significantly higher (P = 0.008) after metastasis than before the detection of metastasis in eight patients. When a cutoff of 10 ng/mL was used, the sensitivity and specificity of serum osteopontin in detecting metastatic melanoma was 87.5%, and the area under the receiver operator characteristic curve was 96%. CONCLUSIONS: Osteopontin is expressed diffusely in tissue sections of hepatic metastases from uveal melanoma, and increased serum osteopontin levels correlate with melanoma metastasis to the liver with high specificity and sensitivity.     

骨桥蛋白在不同侵袭转移潜能葡萄膜黑色素瘤中的表达及意义

背景 骨桥蛋白(OPN)在多种转移性肿瘤组织中表达增高,但在葡萄膜黑色素瘤(UM)中的表达与临床病理特征及侵袭转移是否相关尚不清楚. 目的 研究UM组织及不同转移潜能人UM细胞系MUM-2B、C918和OCM-1A中OPN的表达情况,分析OPN的组织及细胞系表达水平与UM患者临床病理特征与转移预后之间的关系.方法 收集2004年1月至2007年12月在北京同仁医院行眼球摘除手术并已经病理证实为脉络膜黑色素瘤组织的标本共50例,应用免疫组织化学法检测石蜡标本中OPN的表达,分析其与临床资料的相关性.应用定量聚合酶链反应(Q-PCR)技术检测不同侵袭性转移潜能的人UM细胞系中OPN mRNA的表达情况.结果 50例UM组织中发生肝转移者13例,其中10例OPN表达阳性,未发生肝转移的37例中14例OPN表达阳性;上皮型与非上皮型脉络膜黑色素瘤OPN表达阳性者分别为11/15和13/35;肿瘤累及睫状体和未累及者OPN表达阳性者分别为20/30和4/20;上述指标的比较差异均有统计学意义(X2=5.888、5.510、10.470,P＜0.05).患者不同性别、年龄、眼别、肿瘤最大基底径以及是否侵犯巩膜导管间OPN表达阳性例数的比较差异均无统计学意义(P=0.536、0.256、0.802、0.848、0.555).转移潜能细胞系由高到低依次为MUM-2B、C918、OCM-1A,其OPN mRNA相对表达量分别为1.00±0.04、0.91±0.03、0.08±0.01,差异有统计学意义(F=33.135,P＜0.05),MUM-2B、C918中OPN mRNA的表达水平较OCM-1A中明显增高,差异均有统计学意义(P=0.00),而MUM-2B、C918中OPN mRNA的表达水平差异无统计学意义(P=0.804).结论 OPN与UM侵袭能力及转移潜能密切相关,发生转移的UM组织及高侵袭转移性细胞系中OPN表达水平明显升高,提示OPN可能作为预测UM侵袭能力、转移潜能以及患者预后的指标.     

Pyrophosphorolysis detects B-RAF mutations in primary uveal melanoma

PURPOSE: Mutations in the genes that control cell proliferation in cutaneous melanoma are generally uncommon in uveal melanoma. Despite the absence of known activating mutations, the RAF-MEK-ERK, or mitogen-activated protein kinase (MAPK), pathway is usually activated in uveal melanoma. An assay with increased potential to identify mutations is now available, and this study was therefore conducted to reanalyze uveal melanoma cell lines and primary tumors for this mutation. METHODS: Eleven uveal melanoma cell lines and 45 primary uveal melanomas were analyzed for mutations in exon 15 of the B-RAF gene by using pyrophosphorolysis-activated polymerization (PAP). Mutations were validated by sequencing of the PAP product. RESULTS: B-RAF mutations were detected in cell lines OCM-1 and -3 (V600E) and in six primary uveal melanomas. The V600K mutation was detected in one primary uveal melanoma, for which the V600E assay turned out to be sensitive as well. Direct sequencing of the exon 15 PCR product did not reveal the mutations found with the PAP-assay, indicating a low frequency of the mutant allele in primary samples. CONCLUSIONS: Because of the very sensitive PAP technology, B-RAF mutations were found in cell lines and primary uveal melanomas, which suggests that they may occasionally play a role in the activation of the MAPK pathway in uveal melanoma and indicates a higher prevalence of B-RAF mutations in uveal melanoma than was reported earlier. However, the relative scarcity of the B-RAF mutation excludes an elemental role for this mutation in uveal melanoma.     

The effect of ultraviolet radiation on choroidal melanocytes and melanoma cell lines: cell survival and matrix metalloproteinase production

Background Ultraviolet radiation (UVR) can induce DNA damage and regulate the expression of factors important for tumour growth and metastasis, including matrix metalloproteinases (MMPs). Epidemiological studies suggest that chronic UVR exposure, especially during early adulthood, may be a risk factor in patients with choroidal melanoma. However, the effects of UV(R)-B on human choroidal melanocyte survival and growth are unknown. In this study, we investigated if UV(R)-B affected the in vitro survival, growth and MMP production of choroidal melanocytes and melanoma cells. Methods Cultures of primary choroidal melanocytes and melanoma cell lines (OCM-1 and OCM-8) were exposed to UV(R)-B (0–30 mJ/cm²). The cell morphology and growth were examined, and cell viability was assessed using an MTT assay. Gelatin zymography was used to assess the enzymatic activity for MMP-2 and -9 in conditioned media following UV(R)-B treatment. Results UV(R)-B ≥20 mJ/cm² was cytotoxic for choroidal melanocytes. Cytotoxic doses of 5 to 10 mJ/cm² were found for OCM-8 and OCM-1 melanoma cell lines. Low levels of UV(R)-B (2.5 and 3.5 mJ/cm²) significantly reduced melanoma cell viability after 48 h, although melanocyte viability was not affected by doses of UV(R)-B <10 mJ/cm². Conditioned media from melanoma cells and melanocytes displayed pro-MMP-2 activity independent of UV(R)-B. Control and UV(R)-B-treated OCM-1 cells secreted active MMP-2 up to 72 h. Pro-MMP-9 activity was seen from 36 h for control and UV(R)-B-treated OCM-1 and OCM-8 cells. Conclusions Melanocytes appeared more resistant to physiological doses of UV(R)-B than melanoma cells; the potential of melanocytes to initially survive DNA damage following UV(R)-B exposure may be relevant to the subsequent transformation of melanocytes to melanomas. Although UV(R)-B did not induce the production and/or activation of MMP-2 and -9 in melanocytes or melanoma cells, we are currently investigating whether DNA damage-response genes such as p53 and p21 can be regulated following UVR exposure, and whether they are important for choroidal melanoma development. This study was supported in part by grants from the Sydney Foundation for Medical Research (MCM) and the National Health and Medical Research Council, Australia (RMC).