Multiomics to investigate the mechanisms contributing to repression of PTPRC and SOCS2 in pediatric T-ALL: Focus on miR-363-3p and promoter methylation.

T-cell acute lymphoblastic leukemia (T-ALL) is a heterogeneous and aggressive malignancy arising from T-cell precursors. MiRNAs are implicated in negative regulation of gene expression and when aberrantly expressed contribute to various cancer types, including T-ALL. Previously we demonstrated the oncogenic potential of miR-363-3p overexpression in a subgroup of T-ALL patients. Here, using combined proteomic and transcriptomic approaches, we show that miR-363-3p enhances cell growth of T-ALL in vitro via inhibition of PTPRC and SOCS2, which are implicated in repression of the JAK-STAT pathway. We propose that overexpression of miR-363-3p is a novel mechanism potentially contributing to overactivation of JAK-STAT pathway. Additionally, by combining the transcriptomic and methylation data of T-ALL patients, we show that promoter methylation may also contribute to downregulation of SOCS2 expression and thus potentially to JAK-STAT activation. In conclusion, we highlight aberrant miRNA expression and aberrant promoter methylation as mechanisms, alternative to mutations of JAK-STAT-related genes, which might lead to the upregulation of JAK-dependent signaling in T-ALL.