Mycosis fungoides-derived exosomes promote cell motility and are enriched with microRNA-155 and microRNA-1246, and their plasma-cell-free expression may serve as a potential biomarker for disease burden.

BACKGROUND: Literature regarding exosomes as mediators in intercellular communication to promote progression in mycosis fungoides (MF) is lacking. OBJECTIVES: To characterize MF-derived exosomes and their involvement in the disease. METHODS: Exosomes were isolated by ultracentrifugation from cutaneous T-cell lymphoma (CTCL) cell lines, and from plasma of patients with MF and controls (healthy individuals). Exosomes were confirmed by electron microscopy, NanoSight and CD81 staining. Cell-line exosomes were profiled for microRNA array. Exosomal microRNA (exomiRNA) expression and uptake, and plasma-cell-free microRNA (cfmiRNA) were analysed by reverse-transcriptase quantitative polymerase chain reaction. Exosome uptake was monitored by fluorescent labelling and CD81 immunostaining. Migration was analysed by transwell migration assay. RESULTS: MyLa- and MJ-derived exosomes had a distinctive microRNA signature with abundant microRNA (miR)-155 and miR-1246. Both microRNAs were delivered into target cells, but only exomiR-155 was tested, demonstrating a migratory effect on target cells. Plasma levels of cfmiR-1246 were significantly highest in combined plaque/tumour MF, followed by patch MF, and were lowest in controls (plaque/tumour > patch > healthy), while cfmiR-155 was upregulated only in plaque/tumour MF vs. controls. Specifically, exomiR-1246 (and not exomiR-155) was higher in plasma of plaque/tumour MF than in healthy controls. Plasma exosomes from MF but not from controls increased cell migration. CONCLUSIONS: Our findings show that MF-derived exosomes promote cell motility and are enriched with miR-155, a well-known microRNA in MF, and miR-1246, not previously reported in MF. Based on their plasma expression we suggest that they may serve as potential biomarkers for tumour burden.

Unilesional mycosis fungoides is associated with increased expression of microRNA-17~92 and T helper 1 skewing.

BACKGROUND: The molecular basis of unilesional mycosis fungoides (MF), characterized by a solitary lesion that is clinicopathologically indistinguishable from multifocal patch or plaque MF (early MF), is unknown. OBJECTIVES: To investigate the microRNA profile in unilesional MF distinguishing it from early MF. METHODS: Biopsy samples of unilesional MF and early MF were evaluated with the Affymetrix microRNA array, with further comparison with inflammatory dermatosis, using quantitative polymerase chain reaction. NanoString technology was applied to analyse the gene expression of T helper (Th)1 immune markers, and immunohistochemistry was used to evaluate CXCR3 and GATA-binding protein 3 (GATA3) markers for Th1 and Th2 cells, respectively. RESULTS: Unilesional MF had a significantly higher level of expression of all members of the microRNA miR-17~92 cluster than early MF. Specifically, unilesional MF had a higher miR-17 level than early MF and inflammatory dermatoses. There was downregulation of the expression of phosphatase and tensin homolog (PTEN) and CREB1, known targets of miR-17~92 members; higher gene expression of interleukin-2 and interferon-γ; and a statistically lower average percentage of GATA3+ dermal cells (6·7% vs. 42·3%), were detected in unilesional MF compared with early MF. High immunoreactivity of CXCR3 was noted in both unilesional and early MF. CONCLUSIONS: Unilesional MF exhibits a microRNA profile distinct from that of conventional early MF, with a higher level of miR-17~92 members along with Th1 skewing. These findings suggest a robust reactive T-cell immune response in unilesional MF and might account for the localized nature of this disease.