PIWI-interacting RNA 39980 promotes tumor progression and reduces drug sensitivity in neuroblastoma cells.

Neuroblastoma (NB) is the leading pediatric cancer known for its heterogeneity and clinical aggressiveness leading to chemoresistance. Recent evidence in small RNA research has led to the discovery of PIWI-interacting RNAs (piRNAs) which work in an orchestrated fashion to modulate gene expression both in homeostatic conditions and abnormalities like cancer including NB. This study aims to decipher the possible role of a repeat-derived piRNA, piR-39980 (identified from our previous piRNA profiling study in human NB cell lines) in tumorigenesis of NB cells. piR-39980, overexpressed in NB cells act as an oncopiR and promotes tumor progression, while its inhibition resulted in reduced viability, invasion as well as the migration of IMR-32 cells. Interestingly, we observed that inhibition of piRNA induces senescence of NB cells without affecting the classical apoptosis pathway by modulating the expression of JAK3 through target binding. In addition, piR-39980 was found to desensitize the effect of doxorubicin and inhibit drug-induced apoptosis. Overall, we report piR-39980, as the first oncopiR which might serve as a novel therapeutic target for this malignancy.