We found that all 3 INSM1-negative neuroblastoma patients with available follow-up were alive at a median of 15 years, in comparison to 9 of 13 INSM1-positive neuroblastoma patients living at a median of 5 years.
5'-Iodotubercidin treatment and INSM1 inhibition suppressed extracellular signal-regulated kinase 1/2 (ERK1/2) activity and the AKT signaling pathways required for NB cell proliferation.
The current data supports our hypothesis that a positive-feedback loop of sonic hedgehog signaling induced INSM1 through N-myc and INSM1 enhanced N-myc stability contributing to the transformation of human neuroblastoma.
Northern blot analysis and transient transfection of an INSM1 promoter-driven luciferase reporter gene indicated that the INSM1 promoter was active in neuroblastoma (IMR-32), retinoblastoma (Y79), and medulloblastoma (D283 Med) cells, but not in glioblastoma (U-87 MG) cells.