Alterations in expression of specific microRNAs by combination of 4-HPR and EGCG inhibited growth of human malignant neuroblastoma cells.

Malignant neuroblastomas are childhood tumors that remain mostly incurable. We explored efficacy of N-(4-hydroxyphenyl) retinamide (4-HPR) and (-)-epigallocatechin-3-gallate (EGCG) in altering expression of oncogenic microRNAs (OGmiRs) and tumor suppressor miRs (TSmiRs) for controlling growth of human malignant neuroblastoma SK-N-BE2 and IMR-32 cells. Combination of 4-HPR and EGCG most significantly decreased expression of OGmiRs (miR-92, miR-93, and miR-106b) and increased expression of TSmiRs (miR-7-1, miR-34a, and miR-99a) in both cell lines. Overexpression of miR-93 and miR-7-1, respectively, decreased and increased efficacy of treatments. Thus, alterations in expression of specific OGmiRs and TSmiRs by 4-HPR and EGCG inhibited growth of malignant neuroblastomas.