Uveal Melanoma Tissues Research Articles

Genomic evolution of uveal melanoma arising in ocular melanocytosis

Ocular melanocytosis is the most important predisposing condition for the eye cancer uveal melanoma (UM). Here, we present a patient who developed UM arising within ocular melanocytosis who was treated with enucleation (eye removal), which provided an invaluable opportunity to interrogate both the UM and adjacent uveal tissue containing the melanocytosis using whole-exome and deep-targeted sequencing. This analysis revealed a clonal PLCB4 mutation in the melanocytosis, confirming that this is indeed a neoplastic condition and explaining why it predisposes to UM. This mutation was present in 100% of analyzed UM cells, indicating that a PLCB4-mutant cell gave rise to the UM. The earliest aberrations specific to the tumor were loss of Chromosomes 1p, 3, and 9p, which were present in virtually all tumor cells. A mutation in BAP1 arose later on the other copy of Chromosome 3 in a tumor subclone, followed by a gain of Chromosome 8q. These findings provide a mechanistic explanation for the well-known clinical association between ocular melanocytosis and UM by showing that this predisposing condition introduces the first “hit” and thereby increases the stochastic likelihood of acquiring further aberrations leading to UM.

Higher expression of cation transport regulator-like protein 1 (CHAC1) predicts of poor outcomes in uveal melanoma (UM) patients.

The purpose of our present study was to investigate the expression of cation transport regulator-like protein 1 (CHAC1) in uveal melanoma (UM) tissues and its function in UM progression. The mRNA expression of CHAC1 in UM tissues and its prognostic value were investigated based on Gene Expression Omnibus database and The Cancer Genome Atlas database. SP6.5 and M23 UM cell lines with depleted CHAC1 were constructed using small interfering RNA. The viability and migration ability of SP6.5 and M23 UM cells were determined by MTT and wound healing assays, respectively. Western blot was conducted to test the influences of CHAC1 depletion on PI3K signaling pathway. Higher expression of CHAC1 was observed in the UM tissues from patients with liver metastases compared to that from patients without metastases. High CHAC1 expression was correlated with poor prognostic and was an independent predictor for UM patients. Depletion of CHAC1 remarkably inhibited the proliferation and motility of SP6.5 and M23 UM cells. Moreover, the ratios of p-AKT/AKT and p-mTOR/mTOR were reduced notably after silencing CHAC1. Our results suggested that CHAC1 functioned as a facilitator in UM cell proliferation and migration and possessed the potential to be a predictor as well as a therapeutic target for UM patients.

Spatial intratumor heterogeneity in uveal melanoma: Tumor cell subtypes with a presumed invasive potential exhibit a particular epigenetic staining reaction

Cancer evolves from a combination of genetic and epigenetic abnormalities resulting in aberrant gene expression profiles as well as altered epigenomic patterns. Epigenetic alterations such as DNA methylation and histone modification play an important role in tumorigenesis. While in the pathobiology of uveal melanoma (UM) genetic changes have been well characterized, there is growing evidence suggesting that epigenetic changes are also involved. We investigated whether epigenetic modifications (global levels of histone acetylation, DNA methylation, ubiquitination) are detectable in UM tissues compared to healthy controls with respect to inter- and intratumoral heterogeneity. Formalin-fixed paraffin-embedded tissues of primary UM (n = 15), UM metastasis (n = 13), and control choroid (n = 12) were immunohistochemically investigated by two ophthalmic pathologists for global levels of histone acetylation (Histone 3 acetylation, H3Ac; Histone 4 acetylation, H4Ac), DNA methylation (5-methylcytosine, 5-MeC; 5′-hydroxymethylcytosine, 5-hMeC), global ubiquitination (UBC) as well as Ubiquityl-Histone H2A (H2Aub). The nuclear staining intensity of primary tumors, metastases and control choroids was evaluated using a score from 0 to 3, which was multiplied with the percentage of stained cells (score from 0 to 4). The control choroid and the choroid next to the tumor showed a more intense nuclear staining than the primary tumor tissue. The choroid next to the tumor was stained less than the control choroid. The nuclear staining intensity in the tumor was comparable to that in the metastases. The tumor tissue itself often exhibited a heterogeneous staining pattern, as nuclei in the tumor center were less intensely stained than in the periphery. Cells with a presumed invasive potential (extraocular extension, growth along emissary canals) showed also an intense staining reaction. Although no prognostically relevant pattern of global epigentic markers could be identified, our results suggest that epigenetic changes play a role in UM pathogenesis and metastasis. In particular the staining reaction of tumor cell subtypes with a presumed invasive potential warrants further attention. The role of epigenetically relevant interactions with the tumor micromilieu should be further investigated as immune cells are predominantly located in the tumor periphery which showed a different staining intensity than the tumor center. However, as considerable epigenetic diversity exists in primary tumors, studies on biopsy tissue are not recommended for the immunohistochemical investigation of epigenetic markers.

LncRNA PVT1 knockdown affects proliferation and apoptosis of uveal melanoma cells by inhibiting EZH2.

To detect the expression of long non-coding ribonucleic acid (lncRNA) plasmacytoma variant translocation gene 1 (PVT1) in uveal melanoma (UM) tissues, and to investigate its influence on the proliferation and apoptosis of UM cells as well as its mechanism. 40 cases of UM tissues and 40 cases of adjacent tissues surgically resected in our hospital from October 2015 to April 2018 were collected. The expression level of lncRNA PVT1 in these tissues was determined by Reverse Transcription-Polymerase Chain Reaction (RT-PCR). Stable knockdown of lncRNA PVT1 was constructed in human UM cell line OCM-1 using small interfering RNA (siRNA). The impact of lncRNA PVT1 on UM cell proliferation was detected by Cell Counting kit-8 (CCK-8) and colony formation assay. Flow cytometry was applied to measure the apoptotic level of UM cells in the blank control group and lncRNA PVT1 knockdown group. Meanwhile, the expression level of enhancer of zeste homologue 2 (EZH2) was determined by Western blotting. The expression level of lncRNA PVT1 in UM tissues was remarkably higher than that in the adjacent tissues (p<0.05). UM cell proliferation was notably repressed after lncRNA PVT1 knockdown by siRNA. Flow cytometry results indicated that the number of apoptotic UM cells in lncRNA PVT1 knockdown group significantly increased compared with that in the blank control group (p<0.05). The protein expression of EZH2 was suppressed after lncRNA PVT1 knockdown (p<0.05). LncRNA PVT1 knockdown in UM cells can repress the proliferation of UM cells and promote their apoptosis by regulating EZH2 expression.

MiR‐224‐5p inhibits proliferation, migration, and invasion by targeting PIK3R3/AKT3 in uveal melanoma

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. Accumulating investigations have identified the aberrant expression of miRNAs (microRNAs) in UM, such as miR-181, miR-20a, miR-144, miR-146a. The purpose of this study is to investigate the biological function of miR-224-5p in UM. The expression of miR-224-5p, PIK3R3, and AKT3 in 30 tumor tissues and paired adjacent noncancerous tissues were analyzed using Western blot analysis and quantitative real-time polymerase chain reaction (qRT-PCR) assays. Cell proliferation assay, transwell assay, and wound healing assay were used to measure the effects of miR-224-5p on the motility of UM in vitro. Western blot analysis and luciferase assays were used to detect the expression of PIK3R3 and AKT3 as miR-224-5p downstream targets. The results of Western blot analysis and qRT-PCR assays indicated that the expression of miR-224-5p was lower in UM tissues compared to normal tissue, while the expression of PIK3R3 and AKT3 were simultaneously increased. Upregulation of miR-224-5p significantly inhibited capacities of proliferation, invasion, and migration of OCM-1A cells and decreased expression of PIK3R3 and AKT3. Luciferase assay demonstrated PIK3R3 and AKT3 as downstream targets of miR-224-5p. Moreover, upregulating PIK3R3 and AKT3 restrained miR-224-5p-induced inhibition of the motility of OCM-1A cells. Thus, our study proved that miR-224-5p was involved in proliferation, invasion, and migration of UM cells via regulation the expression of PIK3R3 and AKT3. And the results also established a miR-224-5p/PIK3R3/PI3K/AKT axis in the regulation of UM progression, providing an experimental basis for further exploring the miR-224-5p as a therapeutic and diagnosis target for patients with UM.

Digital PCR-Based T-cell Quantification–Assisted Deconvolution of the Microenvironment Reveals that Activated Macrophages Drive Tumor Inflammation in Uveal Melanoma

Uveal melanoma progression can be predicted by gene expression profiles enabling a clear subdivision between tumors with a good (class I) and a poor (class II) prognosis. Poor prognosis uveal melanoma can be subdivided by expression of immune-related genes; however, it is unclear whether this subclassification is justified; therefore, T cells in uveal melanoma specimens were quantified using a digital PCR approach. Absolute T-cell quantification revealed that T-cell influx is present in all uveal melanomas associated with a poor prognosis. However, this infiltrate is only accompanied by differential immune-related gene expression profiles in uveal melanoma with the highest T-cell infiltrate. Molecular deconvolution of the immune profile revealed that a large proportion of the T-cell-related gene expression signature does not originate from lymphocytes but is derived from other immune cells, especially macrophages. Expression of the lymphocyte-homing chemokine CXCL10 by activated macrophages correlated with T-cell infiltration and thereby explains the correlation of T-cell numbers and macrophages. This was validated by in situ analysis of CXCL10 in uveal melanoma tissue with high T-cell counts. Surprisingly, CXCL10 or any of the other genes in the activated macrophage-cluster was correlated with reduced survival due to uveal melanoma metastasis. This effect was independent of the T-cell infiltrate, which reveals a role for activated macrophages in metastasis formation independent of their role in tumor inflammation. IMPLICATIONS: The current report uses an innovative digital PCR method to study the immune environment and demonstrates that absolute T-cell quantification and expression profiles can dissect disparate immune components.

Abnormally expressed JunB transactivated by IL-6/STAT3 signaling promotes uveal melanoma aggressiveness via epithelial-mesenchymal transition.

Uveal melanoma (UM) is the most common primary intraocular tumor in adults, and it carries a high risk of metastasis and mortality. Various proinflammatory cytokines have been found to be significantly increased in the aqueous humor or vitreous fluid of UM patients; however, the role of these cytokines in UM metastasis remains elusive. In the present study, we found that long-term interleukin (IL)-6 exposure promoted the migration and invasion of UM cells, diminished cell–cell adhesion, and enhanced focal adhesion. Moreover, IL-6 treatment decreased the membranous epithelial marker TJP1 and increased the cytoplasmic mesenchymal marker Vimentin. Further investigation demonstrated that JunB played a critical role in IL-6-induced UM epithelial–mesenchymal transition (EMT). In UM cells, the expression of JunB was significantly up-regulated during the IL-6-driven EMT process. Additionally, JunB induction occurred at the transcriptional level in a manner dependent on phosphorylated STAT3, during which activated STAT3 directly bound to the JunB promoter. Importantly, the knockdown of STAT3 prevented the IL-6-induced EMT phenotype as well as cell migration and invasion, whereas JunB overexpression recovered the attenuated aggressiveness of UM cells. Similarly, with IL-6 stimulation, the stable overexpression of JunB strengthened the migratory and invasive capabilities of UM cells and induced the EMT-promoting factors (Snail, Twist1, matrix metalloproteinase (MMP)-2, MMP-14, and MMP-19). Analysis of The Cancer Genome Atlas (TCGA) database indicated that JunB was positively correlated with IL-6 and STAT3 in UM tissues. The present study proposes an IL-6/STAT3/JunB axis leading to UM aggressiveness by EMT, which illustrates the negative side of inflammatory response in UM metastasis.

Somatostatin Receptors as Molecular Targets in Human Uveal Melanoma.

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults, with an incidence of 4–5 cases per million. The prognosis of UM is very poor. In the present study, our aim was to investigate the expression of mRNA and protein for somatostatin receptor types-1, -2, -3, -4, -5 (SSTR-1–5) in human UM tissue samples and in OCM-1 and OCM-3 human UM cell lines by qRT-PCR, western blot and ligand competition assay. The mRNA for SSTR-2 showed markedly higher expression in UM tissues than SSTR-5. The presence of SSTRs was demonstrated in 70% of UM specimens using ligand competition assay and both human UM models displayed specific high affinity SSTRs. Among the five SSTRs, the mRNA investigated for SSTR-2 and SSTR-5 receptors was strongly expressed in both human UM cell lines, SSTR-5 showing the highest expression. The presence of the SSTR-2 and SSTR-5 receptor proteins was confirmed in both cell lines by western blot. In summary, the expression of somatostatin receptors in human UM specimens and in OCM-1 and OCM-3 human UM cell lines suggests that they could serve as a potential molecular target for therapy of UM using modern powerful cytotoxic SST analogs targeting SSTR-2 and SSTR-5 receptors.

MOLECULAR PROGNOSTICS FOR UVEAL MELANOMA.

To review laboratory methods, currently available commercial tests, caveats and clinical tips regarding prognostic analysis of uveal melanoma tissue. A review of the literature was performed focused on the genetic abnormalities found in uveal melanoma cells, their correlation to the development of metastases, the validity of various laboratory approaches in their detection, and the existing commercially available tests for uveal melanoma prognostication. Numerous laboratory methods exist for analyzing genetic material obtained from uveal melanoma cells. Older tests have been gradually replaced with contemporary methods that are simpler with greater accuracy. Two commercially available assays exist which have not been directly compared-a gene expression profiling test has been validated directly through a large, prospective multicenter study and a DNA-based test which uses laboratory methods supported by extensive historical data. There are myriad laboratory methods for prognostic analysis of uveal melanoma tissue. These tests were historically only available to those with access to an outfitted laboratory. Newer commercially available assays have increased the accessibility of prognostic biopsy for uveal melanoma. The various caveats that exist when considering and performing prognostic biopsy of uveal melanoma are discussed.

Novel circular RNA expression profile of uveal melanoma revealed by microarray.

ObjectiveThe present study aimed to investigate circular RNA (circRNA) expression in uveal melanoma (UM).MethodsFirst, we used microarray to compare the expression profiles of circRNA in five UM samples and five normal uvea tissues. Next, bioinformatics analyses, including gene ontology (GO) analysis and pathway analysis, were applied to study these differentially expressed circRNAs to predict pathogenic pathways that may be involved. Quantitative real-time polymerase chain reaction (qRT-PCR) in 20 UM samples and 20 normal uvea samples was used to confirm the circRNA expression profiles obtained from the microarray data. Finally, we analyzed the interaction between validated circRNAs and their potential cancer-associated miRNA targets.ResultsIn total, 50,579 circRNAs [fold change (FC) ≥2.0; P<0.05], including 20,654 up-regulated and 29,925 down-regulated circRNAs, were identified as differentially expressed between UM tissues and normal uvea tissues. We used qRT-PCR to verify seven dysregulated circRNAs indicated by the microarray data, including hsa_circ_0119873, hsa_circ_0128533, hsa_circ_0047924, hsa_circ_0103232, hsa-circRNA10628-6, hsa_circ_0032148 and hsa_circ_0133460, which may be promising candidates to study future molecular mechanisms.ConclusionsThis study explored, for the first time, the abnormal expression of circRNAs in UM and described the expression profile of circRNAs, providing a new potential target for the mechanism of UM and future treatment of UM.

Genome-Wide Analysis of Uveal Melanoma Metastasis-Associated LncRNAs and Their Functional Network.

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. Up to 50% of primary UM cases will develop distant metastasis, but no effective therapies are currently available. The present study aimed to characterize the expression profile of the long noncoding RNAs (lncRNAs) and screen the potential metastasis-associated lncRNAs in UM. A genome-wide analysis of the transcriptome was performed on 11 primary UM tissues (6 metastasized and 5 nonmetastasized) through RNA sequencing. A total of 40,878 lncRNAs were detected in UM, 4,983 of which were novel candidates. We identified 329 differentially expressed lncRNAs (DELs) and 802 differentially expressed mRNAs (DEMs) by comparing the transcriptome profile between metastasized and nonmetastasized UM group. The DEL-DEM coexpression network revealed that the RP11-551L14.4, TCONS_00004101, and TCONS_00004845 DELs had the highest connectivity with the DEMs, coexpressed with 225, 28, and 10 DEMs, respectively, whereas the SPOCD1, PEA15, and SLC44A3 DEMs were most closely connected with the DELs, and were coexpressed with 89, 27, and 22 DELs, respectively. Moreover, 17 and 743 DEMs were targeted by the DELs through cis- or trans-action, respectively. These targeted DEMs were significantly enriched in D-Arginine and D-ornithine metabolism and glycerolipid metabolism of Kyoto Encyclopedia of Genes and Genomes pathways, and enriched in bradykinin receptor activity and haptoglobin binding of gene ontology biological processes. Quantitative real-time PCR confirmed the sequencing data. These findings have provided new insights into the molecular mechanism of UM metastasis and paved the way for further investigations regarding lncRNA in UM.

Long non-coding RNA FTH1P3 facilitates uveal melanoma cell growth and invasion through miR-224-5p.

Growing evidences indicated that Long noncoding RNAs (lncRNAs) played important roles in tumor initiation and progression. However, the function and mechnism of lncRNA ferritin heavy chain 1 pseudogene 3 (FTH1P3) remain unknown in uveal melanoma. We showed that the expression level of FTH1P3 was upregulated in uveal melanoma cell lines and tissues. Elevated expression of FTH1P3 promoted uveal melanoma cell proliferation, cell cycle and migration. Moreover, we found that FTH1P3 was a direct target gene of miR-224-5p in uveal melanoma cell. Overexpression of FTH1P3 suppressed miR-224-5p expression and promoted the expression of Rac1 and Fizzled 5, which were the direct target genes of miR-224-5p. Furthermore, we showed that miR-224-5p expression level was downregulated in uveal melanoma cell lines and tissues. FTH1P3 expression was inversely correlated with the miR-224-5p expression in uveal melanoma tissues. Ectopic expression of miR-224-5p decreased uveal melanoma cell proliferation, cell cycle and migration. Elevated expression of FTH1P3 enhanced uveal melanoma cell proliferation and migration by inhibiting miR-224-5p expression. These results suggest that lncRNA FTH1P3 plays a crucial role in uveal melanoma. Investigation of the underlying mechanism may be a target for the treatment of uveal melanoma.

MiR-155 Promotes Uveal Melanoma Cell Proliferation and Invasion by Regulating NDFIP1 Expression.

MicroRNAs refer to small RNA molecules that destroy the messenger RNA by binding on them inhibiting the production of protein. However, the role of miR-155 in uveal melanoma metastasis remains largely unknown. In this study, we found that miR-155 was upregulated in both uveal melanoma cells and tissues. Transfection of miR-155 mimic into uveal melanoma cells led to an increase in cell growth and invasion; in contrast, inhibition of miR-155 resulted in opposite effects. Also, we identified Nedd4-family interacting protein 1 as a direct target of miR-155, and the expression of Nedd4-family interacting protein 1 was inhibited by miR-155. Furthermore, ectopic expression of Nedd4-family interacting protein 1 restored the effects of miR-155 on cell proliferation and invasion of uveal melanoma cells. In conclusion, miR-155 acts as a tumor promotor in uveal melanoma through increasing cell proliferation and invasion. Thus, miR-155 might serve as a potential therapeutic target in patients with uveal melanoma.

Grb2-associated binder 2 expression and its roles in uveal melanoma invasion.

Uveal melanoma (UM) is characterized by high metastasis and poor prognosis. A more improved understanding of the metastatic mechanism in UM cells is essential for the design of molecular therapy. Grb2-associated binder 2 (Gab2) has been reported to serve important roles in the progression of various types of human cancer. However, the role of Gab2 in the migration and invasion of UM remains unclear. The present study sought to further assess the expression of Gab2 in UM and the role of Gab2 in the invasion of UM cells. Clinical UM tissue samples and UM cell lines were analyzed using western blot analysis for the expression of Gab2. RNA interference was used to investigate the effect of Gab2 on the migratory and invasive characteristics of UM cells in vitro. The expression levels of matrix metalloproteinase (MMP)2, MMP9 and fascin in Gab2-knockdown, and control cells were also detected using western blot analysis. A total of 20 clinical UM samples and a subset of UM cell lines were investigated with uniformly high Gab2 expression. In the in vitro experiment, reduction of Gab2 using small interfering RNA inhibited the migration and invasion of UM cells by mediating MMPs, and fascin expression. These data suggest that Gab2 is a useful prognostic marker for UM and a novel therapeutic target for UM metastasis intervention.

LncRNA HOXA11-AS Exerts Oncogenic Functions by Repressing p21 and miR-124 in Uveal Melanoma.

Long noncoding RNAs (lncRNAs) have been reported to play vital roles in various human cancers. The aim of this study was to explore the critical role of lncRNA HOXA11-AS in uveal melanoma (UM) progression. Briefly, we found that HOXA11-AS is overexpressed in UM tissues and cells; HOXA11-AS could regulate UM cell growth, invasion, and apoptosis. Mechanistically, RNA immunoprecipitation demonstrated that HOXA11-AS could simultaneously interact with enhancer of zeste homolog 2 (EZH2) to suppress its target p21 protein expression. In addition, we demonstrated that HOXA11-AS functioned as a molecular sponge for miR-124, and overexpression of miR-124 attenuated the proliferation and invasion-promoting effect of HOXA11-AS. Collectively, our findings reveal an oncogenic role for HOXA11-AS in UM tumorigenesis.

Evaluation of &lt;em&gt;p53&lt;/em&gt; gene expression and prognosis characteristics in uveal melanoma cases

ObjectiveThe objective of this study was to evaluate the correlation between the expression of p53 gene and the prognosis after local excision in uveal melanoma.Materials and methodsReal-time polymerase chain reaction (RT-PCR) test and Western blot were used to detect the expression of p53 in C918, MUM-2B, and D78 cell lines at the levels of messenger RNA (mRNA) and protein. Immunohistochemistry staining was done in the tissues of 68 patients, which were diagnosed with uveal melanoma. Furthermore, the effects of p53 protein on the invasion abilities of both the cell lines were studied by transinfection of p53 small interfering RNA. The clinical and prognostic data regarding the effect of p53 protein on the patient’s prognosis were calculated and further analyzed by Kaplan–Meier univariate analysis method.ResultsThe results of RT-PCR and Western blot revealed that p53 mRNAs were highly expressed in C918 and MUM-2B cells. The high expression rate of p53 among the 88 uveal melanoma tissues was 77.27%. Transinfection of p53 serine could inhibit the expression of p53 in uveal melanoma and the invasion ability of the cells. This study found that the high expression of p53 and the prognosis of uveal melanoma patients were statistically correlated.ConclusionThe expression of p53 protein in uveal melanoma was unusual and was associated with the invasion ability of uveal melanoma. This indicates that the highest expression of p53 protein indicates worse prognosis of uveal melanoma patients.

MiR-367 promotes uveal melanoma cell proliferation and migration by regulating PTEN.

We aimed to investigate the biological role of miR-367 in uveal melanoma cell growth and migration, and the underlying mechanism responsible. Quantitative real-time polymerase chain reaction was performed to evaluate miR-367 expression in uveal melanoma tissue samples and cell lines. A miR-367 mimic, miR-367 inhibitor, and negative control oligonucleotide were transfected into these cells to investigate the function of this microRNA. In addition, the role of PTEN in miR-367-mediated uveal melanoma cell growth and migration was evaluated. miR-367 was significantly upregulated in uveal melanoma cells and tissue samples (both P < 0.01). Its inhibition suppressed the proliferation, cell cycle transition, and migration of such cells, and increased levels had the opposite effect. PTEN was confirmed to be a target gene of miR-367. More importantly, co-transfection with a PTEN construct lacking the 3'-untranslated region mitigated miR-367 mimic-induced promotion of uveal melanoma cell proliferation and migration. In summary, miR-367 was found to be upregulated in this malignancy, and may promote uveal melanoma cell proliferation and migration, at least in part by regulating PTEN.

Oncogenic role of microRNA‑20a in human uveal melanoma.

As a member of the microRNA (miR)-17-92 cluster, miR-20a has been indicated to be involved in the regulation of the proliferation and invasion of various cancer cells. Previous studies have observed elevated plasma levels of miR-20a in patients with uveal melanoma (UM), compared with normal controls. In the present study, the potential function of miR-20a in UM was investigated. Reverse transcription-quantitative polymerase chain reaction analysis was performed to detect the expression levels of miR-20a in UM cells and tissues. The functions of miR-20a on cell proliferation, migration and invasion were determined in vitro using 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide and Transwell assays, respectively. The expression levels of miR-20a were significantly increased in the UM cells and tissues (P<0.05). Subsequently, miR-20a mimics were transfected into UM cells, which led to increases in cell growth, migration and invasion activities. By contrast, miR-20a inhibition markedly suppressed the viability and motility of UM cells in vitro. These data provided convincing evidence that miR-20a may function as an oncogenic miRNA, and may be involved in promoting cell growth and motility in the molecular etiology of UM, suggesting its potential as a candidate therapeutic target for the treatment of patients with UM.

Prognostic value of legumain in uveal melanoma.

The present study aimed to assess the expression of legumain in uveal melanoma (UM) cell lines and primary UM specimens, and to determine the possible association between legumain expression and clinical as well as pathological characteristics to reveal its impact on the prognosis of patients with UM. Records of primary UM cases treated at Beijing Tongren Hospital and Tianjin Eye Hospital between 1996 and 2005 were retrieved for analysis and a total of 82 patients with uveal melanoma were included in the study. The expression of legumain in the formalin-fixed and paraffin-embedded surgical specimens of these 82 patients was determined using immunohistochemical analysis. In addition, the expression of legumain was examined in two uveal melanoma cell lines using polymerase chain reaction and western blot analyses. The association of legumain expression with clinical/pathological characteristics was analyzed using the χ2 and Fisher's exact test. In addition, the impact of legumain on the prognosis of patients with uveal melanoma was examined. Upregulation of legumain was more predominant in the highly invasive uveal melanoma cell line MUM-2B compared with that in the MUM-2C with low invasiveness. Of 82 primary uveal melanoma tissues, 35 exhibited high expression of legumain, while the other 47 specimens exhibited low or negative expression of legumain. High legumain expression was primarily associated with local invasion of UM. Overall survival analysis revealed that the patients with high legumain expression exhibited poorer survival than patients with low/negative legumain expression. These findings suggested that upregulation of legumain is associated with malignant behavior of UM and that legumain may be used as an negative prognostic factor as well as a therapeutic target.

Clinico-Pathological Association of Delineated miRNAs in Uveal Melanoma with Monosomy 3/Disomy 3 Chromosomal Aberrations.

PurposeTo correlate the differentially expressed miRNAs with clinico-pathological features in uveal melanoma (UM) tumors harbouring chromosomal 3 aberrations among South Asian Indian cohort.MethodsBased on chromosomal 3 aberration, UM (n = 86) were grouped into monosomy 3 (M3; n = 51) and disomy 3 (D3; n = 35) by chromogenic in-situ hybridisation (CISH). The clinico-pathological features were recorded. miRNA profiling was performed in formalin fixed paraffin embedded (FFPE) UM samples (n = 6) using Agilent, Human miRNA microarray, 8x15KV3 arrays. The association between miRNAs and clinico-pathological features were studied using univariate and multivariate analysis. miRNA-gene targets were predicted using Target-scan and MiRanda database. Significantly dys-regulated miRNAs were validated in FFPE UM (n = 86) and mRNAs were validated in frozen UM (n = 10) by qRT-PCR. Metastasis free-survival and miRNA expressions were analysed by Kaplen-Meier analysis in UM tissues (n = 52).ResultsUnsupervised analysis revealed 585 differentially expressed miRNAs while supervised analysis demonstrated 82 miRNAs (FDR; Q = 0.0). Differential expression of 8 miRNAs: miR-214, miR-149*, miR-143, miR-146b, miR-199a, let7b, miR-1238 and miR-134 were studied. Gene target prediction revealed SMAD4, WISP1, HIPK1, HDAC8 and C-KIT as the post-transcriptional regulators of miR-146b, miR-199a, miR-1238 and miR-134. Five miRNAs (miR-214, miR146b, miR-143, miR-199a and miR-134) were found to be differentially expressed in M3/ D3 UM tumors. In UM patients with liver metastasis, miR-149* and miR-134 expressions were strongly correlated.ConclusionUM can be stratified using miRNAs from FFPE sections. miRNAs predicting liver metastasis and survival have been identified. Mechanistic linkage of de-regulated miRNA/mRNA expressions provide new insights on their role in UM progression and aggressiveness.