Introduction: Previous studies have shown that miR-373 functions as either a tumor suppressor or an oncogene depending on which type of cancer it's operating in. However, the functional role of miR-373 in neuroblastoma (NB) remains largely unclear.
Methods: Expression of miR-373 and SRC kinase signaling inhibitor 1 (SRCIN1) in 20 metastatic and 20 primary NB tissues was detected by quantitative real-time PCR (qRT-PCR) and Western blotting. MTT assay, flow cytometry analysis and transwell migration and invasion assays were performed to evaluate the influence of miR-373 inhibition on the growth, migration and invasion of NB cells, respectively. In vivo experiment was applied to determine the effect of miR-373 inhibition on tumor growth. Dual-luciferase reporter assay was used to confirm the interaction between miR-373 and SRCIN1.
Results: We observed a significant increase in the expression of miR-373 in metastatic NB samples compared with primary NB samples, and this was inversely correlated with SRCIN1 expression. Functional studies revealed that depletion of miR-373 inhibited in vitro NB cell growth, migration and invasion, and also suppressed tumor growth in an in vivo mouse model. Moreover, we identified that SRCIN1 was a direct and functional target gene of miR-373. Silencing of SRCIN1 partially rescued the antimiR-373-mediated inhibition of cell growth, migration and invasion.
Conclusion: The data from our study verified a potential oncogenic role of miR-373 in NB cells that occurs through direct targeting SRCIN1. The newly identified miR-373/SRCIN1 axis represents a new potential candidate for therapeutic intervention of malignant NB.
Keywords: NB; SRCIN1; growth; invasion; miR-373; migration.