Characterization, treatment, and outcome of uveal melanoma in the first two years of life

Hindsight: Review of Preclinical Disease Models for the Development of New Treatments for Uveal Melanoma

The molecular, histopathological, genomic and transcriptomic characteristics of uveal melanoma (UM) have identified four molecular subgroups with different clinical outcomes. Despite the improvements in UM classification and biological pathology, current treatments do not reduce the occurrence of metastasis. The development of effective adjuvant and metastatic therapies for UM has been slow and extremely limited. Preclinical models that closely resemble the molecular and genetic UM subgroups are essential for translating molecular findings into improved clinical treatment. In this review, we provide a retrospective view of the existing preclinical models used to study UM, and give an overview of their strengths and limitations. We review targeted therapy clinical trial data to evaluate the gap in the translation of preclinical findings to human studies. Reflecting on the current high attrition rates of clinical trials for UM, preclinical models that effectively recapitulate the human in vivo situation and/or accurately reflect the subtype classifications would enhance the translational impact of experimental data and have crucial implications for the advancement of personalised medicine.

UVEAL MELANOMA IN A 15-YEAR-OLD GIRL. CASE REPORT

Uveal melanoma is the most common intraocular tumour in adults, it is a form of cancer that affects mostly older adults, as the average age at detection of this tumour is 60 years, but it can occur in any age group with no significant gender difference. However, uveal melanoma is very rare in children compared to the adult population, accounting for 1 % of all cases. In pediatric patients, malignant uveal melanoma is more frequently manifested during puberty, leading to speculation of an association between uveal melanoma and growth hormone levels. Prognostic factors for uveal melanoma include tumour histology, chromosomal abnormalities, tumour size, extrascleral spread and tumour location. Risk factors for uveal melanoma include melanocytosis, neurofibromatosis type 1 and dysplastic naevus syndrome. Some studies point to a significantly lower risk of developing metastases in younger patients, but the prognosis of uveal melanoma in children is not yet fully known. Clinical signs and treatment options for malignant uveal melanoma in children are still under discussion. Differential diagnosis of uveal lesions in children can sometimes be very difficult, as evidenced by following case report in which authors describe a case of choroidal melanoma in a 15-year-old girl.

MSK1 promotes cell proliferation and metastasis in uveal melanoma by phosphorylating CREB

INTRODUCTION

Uveal melanoma is known as a frequent intraocular tumor, with high metastasis and poor prognosis. Mitogen- and stress-activated protein kinase 1 (MSK1) is a serine/threonine kinase that has been reported to be associated with tumor progression in several types of human cancer. However, the role of MSK1 has rarely been studied in uveal melanoma and the underlying mechanism remained unclear.

MATERIAL AND METHODS

The expression level of MSK1 in human uveal melanoma tissues and normal uveal tissues was determined by qRT-PCR analysis, western blotting and immunohistochemistry (IHC). Subsequently, MTT assay, colony formation assay and flow cytometry assay were performed to assess the effects of MSK1 on cell proliferation. Wound-healing and transwell chamber assays were adopted to clarify the role of MSK1 in cell metastasis. Finally, the function of MSK1 was confirmed in vivo in a tumor-bearing mouse model.

RESULTS

The expression levels of MSK1 and p-cyclic AMP-responsive element binding protein (CREB) were strongly up-regulated in human uveal melanoma tissues. MSK1 overexpression facilitated cell viability and clone formation, and promoted migration and invasion of uveal melanoma cells. However, mutation of cyclic AMP-responsive element binding protein (CREB) at Ser133 residues reversed the effect of MSK1 on uveal melanoma cell proliferation and metastasis. The in vivo experiment suggested that the tumor weight was lower and the tumor mass grew more slowly in the shMSK1 group as compared to the shNC group.

CONCLUSIONS

MSK1 promotes proliferation and metastasis of uveal melanoma cells by phosphorylated CREB at Ser133 residues. Therefore, MSK1 could be a promising candidate for uveal melanoma therapy and especially has tremendous potential in the treatment of cancers in which the MSK1-CREB pathway is abnormally active.

Posterior uveal melanoma in adolescents and children: current perspectives

Recognizing that <1% of all uveal melanomas occur in young persons, and that very few clinicians encounter more than a few such cases over an extended career, we felt that a retrospective review of literature and sharing of our clinical experience would be appropriate to remind readers about this age subgroup of patients with posterior uveal melanoma. This interest stems from the increase in reported cases of uveal melanoma in younger individuals and recent advances in the field.

Targeted silencing of the ADP-ribosyltransferase 3 gene inhibits the migration ability of melanoma cells

Melanoma is the most common primary intraocular malignancy and metastasis of melanoma to other organs often results in a poor prognosis. ADP-ribosyltransferase 3 (ART3) is involved in cell division and DNA repair. However, its biological function in melanoma remains unclear. In the present study, it was identified that ART3 is highly expressed in melanoma cells and melanoma tissues compared with the normal RPE cell line, and adjacent normal tissue, respectively. Small interfering RNA and short hairpin RNA were used to silence ART3 gene expression, and the results revealed that the silencing of ART3 inhibits the migratory ability of melanoma cells. The present study indicates that ART3 serves a notable role in the metastasis of melanoma and provides a potential therapeutic target for this disease.

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.

Multifocal iris melanoma in a 2-year-old managed with I-125 plaque brachytherapy

We report a 23-month-old patient presenting with multifocal iris melanoma who underwent plaque brachytherapy with full corneal coverage. The lesion demonstrated several high-risk clinical and histopathologic features associated with iris melanoma in adults, including growth and angle seeding. The patient has been subsequently followed for 3.5 years with no evidence of recurrence. This report demonstrates the importance of serial examination of suspected melanocytic iris lesions in very young children and the effective treatment option of globe-sparing radiation therapy.

[Uveal and iridociliary melanomas in young patients : A retrospective analysis of 57 cases]

BACKGROUND

Uveal melanomas (UM) are rare malignancies in young patients. It is unknown if UM in young patients significantly differs from those in older patients concerning tumor size and localization, metastasis and genetics. The aim of this study was to evaluate the clinical course and tumor characteristics in young patients with UM.

MATERIAL AND METHODS

All patients with UM below the age of 32 years who had been treated at our hospital were included in the study. Patient age and sex, duration of symptoms, visual impairment, tumor size and location, genetics, therapy, follow-up interventions and tumor-associated deaths were documented.

RESULTS

A total of 57 patients (67 % male, mean age 24.7 years) were included in the study with an average symptomatic course of 5 months. Of the patients 8 (14 %) had an initial visual acuity of ≥ 0.9, 16 (28 %) 0.5-0.8, 22 (39 %) 0.05-0.4 and 9 (16 %) < 0.05 (no data for 2 patients, 4 %). After therapy visual acuity was < 0.05 in 54 % and 53 % of the tumors were choroidal UM (70 % juxtapapillary/circumpapillary), whereas 47 % were ciliochoroidal (54 % with iridociliary involvement). The average tumor size was 12.7 ± 3.6 mm with an average prominence of 6.2 ± 3.2 mm. Genetic evaluation (n = 16) revealed disomy 3 in 64 % and 54 % of the patients received radiotherapy with local application of ruthenium 106. In 46 % of cases follow-up interventions were neccessary including 70 % due to radiogenic retinopathy.

CONCLUSION

In young patients UM did not show any preferred localization. The majority of genetically evaluated tumors revealed disomy 3 with no significant correlation to tumor location. Independent of tumor size, location and therapy, approximately half of the patients needed follow-up interventions, predominantly due to radiogenic retinopathy.

Mutational status of IDH1 in uveal melanoma

Uveal (intraocular) melanoma is an uncommon malignancy that comprises a small percentage of all melanoma cases. While many uveal melanomas harbor mutations in the BRCA-Associated Protein 1 (BAP1) gene, the genetics of non-BAP1 associated tumors are not completely understood. Recent studies have shown that a small subset of non-uveal melanomas hold mutations in isocitrate dehydrogenase (IDH), but the mutational status of IDH in uveal melanoma is unclear. Mutations in IDH are strongly prognostic and predictive of tumor behavior in other cancers, mainly diffuse gliomas, which commonly contain the IDH1-R132H mutation. For this study, we hypothesized that uveal melanoma may contain the IDH1-R132H mutation, similar to non-uveal melanoma and other cancers. A search of our institutional pathology files identified 50 consecutive cases of uveal melanoma with additional material utilized for retrospective IDH1-R132H immunohistochemical testing. The demographics of these patients included similar ages, gender distributions, and other clinical characteristics as described in previous studies. Similarly, histological subtype distributions and the presence of high risk pathologic features were consistent with other reports. All 50 of the uveal melanoma cases demonstrated negativity for IDH1-R132H by immunohistochemistry. This rate is unlike that of non-uveal melanoma and further supports their distinct molecular oncogenic profile.

MiR-144 Inhibits Uveal Melanoma Cell Proliferation and Invasion by Regulating c-Met Expression

MicroRNAs (miRNAs) are a group endogenous small non-coding RNAs that inhibit protein translation through binding to specific target mRNAs. Recent studies have demonstrated that miRNAs are implicated in the development of cancer. However, the role of miR-144 in uveal melanoma metastasis remains largely unknown. MiR-144 was downregulated in both uveal melanoma cells and tissues. Transfection of miR-144 mimic into uveal melanoma cells led to a decrease in cell growth and invasion. After identification of two putative miR-144 binding sites within the 3' UTR of the human c-Met mRNA, miR-144 was proved to inhibit the luciferase activity inMUM-2B cells with a luciferase reporter construct containing the binding sites. In addition, the expression of c-Met protein was inhibited by miR-144. Furthermore, c-Met-mediated cell proliferation and invasion were inhibited by restoration of miR-144 in uveal melanoma cells. In conclusion, miR-144 acts as a tumor suppressor in uveal melanoma, through inhibiting cell proliferation and migration. miR-144 might serve as a potential therapeutic target in uveal melanoma patients.

MicroRNA dysregulation in uveal melanoma: a new player enters the game

Uveal melanoma is the second most common form of melanoma and a predominant intraocular malignant tumor in adults. The development of uveal melanoma is a multistep process involving genetic and epigenetic alteration of proto-oncogenes and tumor-suppressor genes. Recent discoveries have shed a new light on the involvement of a class of noncoding RNA known as microRNAs (miRNAs) in uveal melanoma. A lot of miRNAs show differential expressions in uveal melanoma tissues and cell lines. Genes coding for these miRNAs have been characterized as novel oncogene and tumor-suppressor genes based on findings that these miRNAs control malignant phenotypes of uveal melanoma cells. Several studies have confirmed that dysregulation of miRNAs promotes cell-cycle progression, confers resistance to apoptosis, and enhances invasiveness and metastasis. Moreover, several miRNAs have also been shown to correlate with uveal melanoma initiation and progression, and thus may be used as biomarkers for early diagnosis and prognosis. Elucidating the biological aspects of miRNA dysregulation may help us better understand the pathogenesis of uveal melanoma and promote the development of miRNA directed-therapeutics against this disease.