miRNA profiling in vitreous humor, vitreal exosomes and serum from uveal melanoma patients: Pathological and diagnostic implications

Abstract

Uveal melanoma (UM) represents approximately 5-6% of all melanoma diagnoses and up to 50% of patients succumb to their disease. Although several methods are available, accurate diagnosis is not always easily feasible because of potential accidents (e.g., intraocular hemorrhage). Based on the assumption that the profile of circulating miRNAs is often altered in human cancers, we verified whether UM patients showed different vitreous humor (VH) or serum miRNA profiles with respect to healthy controls. By using TaqMan Low Density Arrays, we analyzed 754 miRNAs from VH, vitreal exosomes, and serum of 6 UM patients and 6 healthy donors: our data demonstrated that the UM VH profile was unique and only partially overlapping with that from serum of the same patients. Whereas, 90% of miRNAs were shared between VH and vitreal exosomes, and their alterations in UM were statistically overlapped with those of VH and vitreal exosomes, suggesting that VH alterations could result from exosomal dysregulation. We report 32 miRNAs differentially expressed in UM patients in at least 2 different types of samples analyzed. We validated these data on an independent cohort of 12 UM patients. Most alterations were common to VH and vitreal exosomes (e.g., upregulation of miR-21,-34 a,-146a). Interestingly, miR-146a was upregulated in the serum of UM patients, as well as in serum exosomes. Upregulation of miR-21 and miR-146a was also detected in formalin-fixed, paraffin-embedded UM, suggesting that VH or serum alterations in UM could be the consequence of disregulation arising from tumoral cells. Our findings suggest the possibility to detect in VH and serum of UM patients "diagnostic" miRNAs released by the affected eye: based on this, miR-146a could be considered a potential circulating marker of UM.

Retinal and Circulating miRNAs in Age-Related Macular Degeneration: An In vivo Animal and Human Study

“…We used miR-320a as reference gene for normalization of human serum samples (Ragusa et al, 2015), U6 and miR-16 for rat serum and retina samples (Tea et al, 2013). Real Time PCRs was carried out on a 7,900 HT Fast Real Time PCR System (Applied Biosystems, Monza, Italy).…”

Increased Ocular Levels of MicroRNA-148a in Cases of Retinal Detachment Promote Epithelial–Mesenchymal Transition

“…For instance, miR-155 has been shown to promote the expansion of pathogenic Th17 cells, which mediate experimental uveitis 41 ; intravitreal miR-21 and miR-146 have been demonstrated as tumor markers of uveal melanoma 26 ; and intravitreal miR-146 has been demonstrated to control retinal inflammation in diabetic retinitis. 23 Further, the expression levels of microRNA transcripts have been compared between patients with proliferative diabetic retinopathy and patients with MH.…”

“…In group 3, four blood serum samples were collected in addition to SRF from the same patients (Nos. [26][27][28][29].…”

Biology, Therapy and Implications of Tumor Exosomes in the Progression of Melanoma

“…A study by Ragusa et al revealed that exosomes derived from uveal melanoma patients contained a common miRNA in the exosomes, miR-146a, within the vitreous humor, as well as those circulating through the body [93]. Another miRNA in exosomes, miR-126b, was down-regulated only in patients with advanced melanoma compared to healthy donors [94].…”