Monosomy 3 Influences Epithelial-Mesenchymal Transition Gene Expression in Uveal Melanoma Patients; Consequences for Liquid Biopsy

Heterogeneity and molecular landscape of melanoma: implications for targeted therapy

Uveal cancer (UM) offers a complex molecular landscape characterized by substantial heterogeneity, both on the genetic and epigenetic levels. This heterogeneity plays a critical position in shaping the behavior and response to therapy for this uncommon ocular malignancy. Targeted treatments with gene-specific therapeutic molecules may prove useful in overcoming radiation resistance, however, the diverse molecular makeups of UM call for a patient-specific approach in therapy procedures. We need to understand the intricate molecular landscape of UM to develop targeted treatments customized to each patient's specific genetic mutations. One of the promising approaches is using liquid biopsies, such as circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA), for detecting and monitoring the disease at the early stages. These non-invasive methods can help us identify the most effective treatment strategies for each patient. Single-cellular is a brand-new analysis platform that gives treasured insights into diagnosis, prognosis, and remedy. The incorporation of this data with known clinical and genomics information will give a better understanding of the complicated molecular mechanisms that UM diseases exploit. In this review, we focused on the heterogeneity and molecular panorama of UM, and to achieve this goal, the authors conducted an exhaustive literature evaluation spanning 1998 to 2023, using keywords like "uveal melanoma, "heterogeneity". "Targeted therapies"," "CTCs," and "single-cellular analysis".

Factors influencing the diagnostic and prognostic values of circulating tumor cells in breast cancer: a meta-analysis of 8,935 patients

Background

Circulating tumor cells (CTCs) could serve as a predictive biomarker in breast cancer (BC). Due to its high heterogeneity, the diagnostic and prognostic values of CTC are challenging.

Methods

We searched published studies from the databases of PubMed, Cochrane Library, Embase, and MEDLINE. The detection capability and hazard ratios (HRs) of CTCs were extracted as the clinical diagnosis and prognosis evaluation. Subgroup analyses were divided according to the detection methods, continents, treatment periods, therapeutic plans, and cancer stages.

Results

In this study, 35 publications had been retrieved with 8,935 patients enrolled. The diagnostic efficacy of CTC detection has 74% sensitivity and 98% specificity. The positive CTC detection (CTC+ ) would predict worse OS and PFS/DFS in both mid-therapy and post-therapy (HROS, 3.09; 95% CI, 2.17–4.39; HRPFS/DFS, 2.06; 95% CI, 1.72–2.47). Moreover, CTC+ indicated poor survival irrespective of the treatment phases and sampling times (HROS, 2.43; 95% CI, 1.85–3.19; HRPFS/DFS, 1.82; 95% CI, 1.66–1.99). The CTC+ was associated with poor survival regardless of the continents of patients (HROS = 2.43; 95% CI, 1.85–3.19).

Conclusion

Our study suggested that CTC+ was associated with a worse OS and PFS/DFS in the Asian population. The detection method, the threshold level of CTC+ , therapeutic approaches, and sampling times would not affect its diagnostic and prognostic values.

Circulating Tumor DNA as a Prognostic Factor in Patients With Resectable Hepatic Metastases of Uveal Melanoma

OBJECTIVE

We report here the results of a prospective study of circulating tumor DNA (ctDNA) detection in patients undergoing uveal melanoma (UM) liver metastases resection (NCT02849145).

BACKGROUND

In UM patients, the liver is the most common and often only site of metastases. Local treatments of liver metastases, such as surgical resection, have a likely benefit in selected patients.

METHODS

Upon enrollment, metastatic UM patients eligible for curative liver surgery had plasma samples collected before and after surgery. GNAQ / GNA11 mutations were identified in archived tumor tissue and used to quantify ctDNA by droplet digital polymerase chain reaction which was then associated with the patient's surgical outcomes.

RESULTS

Forty-seven patients were included. Liver surgery was associated with a major increase of cell-free circulating DNA levels, with a peak 2 days after surgery (∼20-fold). Among 40 evaluable patients, 14 (35%) had detectable ctDNA before surgery, with a median allelic frequency of 1.1%. These patients experienced statistically shorter relapse-free survival (RFS) versus patients with no detectable ctDNA before surgery (median RFS: 5.5 vs 12.2 months; hazard ratio=2.23, 95% CI: 1.06-4.69, P =0.04), and had a numerically shorter overall survival (OS) (median OS: 27.0 vs 42.3 months). ctDNA positivity at postsurgery time points was also associated with RFS and OS.

CONCLUSIONS

This study is the first to report ctDNA detection rate and prognostic impact in UM patients eligible for surgical resection of their liver metastases. If confirmed by further studies in this setting, this noninvasive biomarker could inform treatment decisions in UM patients with liver metastases.

Suicide-Gene-Modified Extracellular Vesicles of Human Primary Uveal Melanoma in Future Therapies

Extracellular vesicles secreted from uveal melanoma (UM) cells are involved in the establishment of the premetastatic niche and display transforming potential for the formation of metastases, preferentially in the liver. In this study, we cultivated human primary UM cells and uveal melanoma-associated fibroblasts in vitro to be transduced by infection with a retrovirus containing the suicide gene-fused yeast cytosine deaminase::uracil phospho-ribosyl transferase (yCD::UPRT). A homogenous population of yCD::UPRT-UM cells with the integrated provirus expressed the gene, and we found it to continuously secrete small extracellular vesicles (sEVs) possessing mRNA of the suicide gene. The yCD::UPRT-UM-sEVs were internalized by tumor cells to the intracellular conversion of the prodrug 5-fluorocytosine (5-FC) to the cytotoxic drug 5-fluorouracil (5-FU). The host range of the yCD::UPRT-UM-sEVs was not limited to UMs only. The yCD::UPRT-UM-sEVs inhibited the growth of the human cutaneous melanoma cell line A375 and uveal melanoma cell line MP38, as well as other primary UMs, to various extents in vitro. The yCD::UPRT-UM-sEVs hold the therapeutic and prophylactic potential to become a therapeutic drug for UM. However, the use of yCD::UPRT-UM-sEVs must first be tested in animal preclinical studies.

USP2 promotes cell proliferation and metastasis in choroidal melanoma via stabilizing Snail

BACKGROUND

Choroidal melanoma (CM) is an intraocular tumor that arises from melanocytes. While ubiquitin-specific protease 2 (USP2) modulates the progression of numerous diseases, its role in CM is not known. This study aimed to determine the role of USP2 in CM and elucidate its molecular mechanisms.

METHODS

MTT, Transwell, and wound-scratch assays were used to investigate the function of USP2 in the proliferation and metastasis of CM. Western blotting and qRT-PCR were used to analyze the expression of USP2, Snail, and factors associated with the epithelial-mesenchymal transition (EMT). The relationship between USP2 and Snail was explored by co-immunoprecipitation and in vitro ubiquitination assays. A nude mouse model of CM was established for verifying the role of USP2 in vivo.

RESULTS

USP2 overexpression promoted proliferation and metastasis, and induced the EMT in CM cells in vitro, while specific inhibition of USP2 by ML364 produced the opposite effects. ML364 also suppressed CM tumor growth in vivo. Mechanistically, USP2 is known to deubiquitinate Snail, stabilizing the latter through the removal of its K48 poly-ubiquitin chains. However, a catalytically inactive form of USP2 (C276A) had no effect on Snail ubiquitination and failed to increase Snail protein expression. The C276A mutant was also unable to promote CM cell proliferation, migration, and invasion, as well as EMT progression. Furthermore, Snail overexpression partly counteracted the effects of ML364 on proliferation and migration, while rescuing the effects of the inhibitor on the EMT.

CONCLUSIONS

The findings demonstrated that USP2 modulated CM development through the stabilization of Snail and suggest that USP2 may be a useful target for the development of novel treatments for CM.

Methylation-driven gene DLL3 is a potential prognostic biomarker in ocular melanoma correlating with metastasis

Background

Ocular melanoma is an aggressive malignancy with a high rate of metastasis and poor prognosis. Increasing evidence indicated that DNA methylation plays an important role in the occurrence and development of ocular melanoma. Hence, exploring new diagnostic and prognostic biomarkers at the genetic level may be beneficial to the prognosis of patients with ocular melanoma.

Methods

We collected DNA methylation and gene expression profiles of human UM (uveal melanoma) and CM (conjunctival melanoma) samples from various datasets. We conducted differential methylation and expression analyses to screen the potential biomarkers. Correlation analysis was performed to investigate the relationships between the expression level of DLL3 (delta-like protein 3) and the methylation level of its corresponding CpGs. We explored the prognostic and diagnostic value of DLL3 in UM and CM. Functional annotation and GSEA (gene set enrichment analysis) were applied to get insight into the possible biological roles of DLL3. A cohort of 60 ocular melanoma patients as well as UM and CM cell lines were used to validate our findings in bioinformatic analyses.

Results

We found that DLL3 was a methylation-driven gene correlating with UM metastasis. The CpGs of DLL3 are mainly located in the gene body and their methylation level positively correlated to DLL3 expression. Multivariate Cox regression analysis revealed that DLL3 was an independent protective factor for UM patients. High DLL3 expression significantly prolonged the overall survival and disease-free survival of UM patients. DLL3 also showed a promising power to distinguish CM from normal tissues. Functional annotation exhibited that DLL3 may suppress UM progression through modulating immune activities and down-regulating various signaling pathways. External datasets, biospecimens, and cell lines further validated the aberrant expression and prognostic role of DLL3 in ocular melanoma.

Conclusion

Methylation-driven gene DLL3 could serve as a new potential diagnostic and prognostic biomarker in ocular melanoma. Our findings may contribute to improving the clinical outcomes of patients with UM or CM.

Future perspectives of uveal melanoma blood based biomarkers

Uveal melanoma (UM) is the most common primary intraocular malignancy affecting adults. Despite successful local treatment of the primary tumour, metastatic disease develops in up to 50% of patients. Metastatic UM carries a particularly poor prognosis, with no effective therapeutic option available to date. Genetic studies of UM have demonstrated that cytogenetic features, including gene expression, somatic copy number alterations and specific gene mutations can allow more accurate assessment of metastatic risk. Pre-emptive therapies to avert metastasis are being tested in clinical trials in patients with high-risk UM. However, current prognostic methods require an intraocular tumour biopsy, which is a highly invasive procedure carrying a risk of vision-threatening complications and is limited by sampling variability. Recently, a new diagnostic concept known as "liquid biopsy" has emerged, heralding a substantial potential for minimally invasive genetic characterisation of tumours. Here, we examine the current evidence supporting the potential of blood circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), microRNA (miRNA) and exosomes as biomarkers for UM. In particular, we discuss the potential of these biomarkers to aid clinical decision making throughout the management of UM patients.

KIT Expression Is Regulated by DNA Methylation in Uveal Melanoma Tumors

Uveal melanoma (UM) is an ocular tumor with a dismal prognosis. Despite the availability of precise molecular and cytogenetic techniques, clinicopathologic features with limited accuracy are widely used to predict metastatic potential. In 51 UM tissues, we assessed a correlation between the expression of nine proteins evaluated by immunohistochemistry (IHC) (Melan-A, S100, HMB45, Cyclin D1, Ki-67, p53, KIT, BCL2, and AIFM1) and the presence of UM-specific chromosomal rearrangements measured by multiplex ligation-dependent probe amplification (MLPA), to find IHC markers with increased prognostic information. Furthermore, mRNA expression and DNA methylation values were extracted from the whole-genome data, achieved by analyzing 22 fresh frozen UM tissues. KIT positivity was associated with monosomy 3, increasing the risk of poor prognosis more than 17-fold (95% CI 1.53–198.69, p = 0.021). A strong negative correlation was identified between mRNA expression and DNA methylation values for 12 of 20 analyzed positions, five located in regulatory regions of the KIT gene (r = −0.658, p = 0.001; r = −0.662, p = 0.001; r = −0.816; p < 0.001; r = −0.689, p = 0.001; r = −0.809, p < 0.001, respectively). DNA methylation β values were also inversely associated with KIT protein expression (p = 0.001; p = 0.001; p = 0.015; p = 0.025; p = 0.002). Our findings, showing epigenetic deregulation of KIT expression, may contribute to understanding the past failure to therapeutically target KIT in UM.

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.