Nkx2-2as suppression contributes to the pathogenesis of Sonic Hedgehog medulloblastoma

Aberrant Hedgehog signaling and excessive activation of the Gli family of transcriptional activators are key drivers of medulloblastoma (MB), the most common human pediatric brain malignancy. MB originates mainly from cerebellar granule neuron progenitors (CGNP), but the mechanisms underlying CGNP transformation remain largely obscure. In this study, we found that suppression of the non-coding RNA Nkx2-2as promotes Sonic Hedgehog (Shh)-potentiated MB development. Nkx2-2as functioned as a competing endogenous RNA (ceRNA) against miR-103 and miR-107, sequestering them and thereby de-repressing their tumor suppressive targets BTG2 and LATS1 and impeding cell division and migration. We also found that Nkx2-2as tethered miR-548m and abrogated its LATS2 targeting activity, Shh signaling impaired Nkx2-2as expression by upregulating the transcriptional repressor FoxD1. In clinical specimens of Shh-subgroup MB we validated coordinated expression of the aforementioned proteins. Notably, exogenous expression of Nkx2-2as suppressed tumorigenesis and prolonged animal survival in MB mouse models. Our findings illuminate the role of non-coding RNAs in Hedgehog signaling and MB occurrence, with implications for identifying candidate therapeutic targets for MB treatment.

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