LINC01320 facilitates cell proliferation and migration of ovarian cancer via regulating PURB/DDB2/NEDD4L/TGF-β axis

Ovarian cancer (OC) is one of the most prevalent and lethal malignancies affecting the female reproductive system, due to its tendency for metastasis and recurrence. This study identified the overexpression of LINC01320 (or long intergenic nonprotein coding RNA 1320) in tissues of ovarian cancer through the analysis of patient samples and online datasets. In vitro and in vivo experiments demonstrate that silencing of LINC01320 expression led to inhibition of proliferation and metastasis of OC cells. RNA pull-down followed by liquid chromatography tandem mass spectrometry (RNA pull-down-LC-MS/MS) revealed that LINC01320 interacted with purine-rich element binding protein B (PURB), a transcriptional repressor. Furthermore, the RNA-seq analysis identified damage-specific DNA binding protein 2 (DDB2) as a major common target of LINC01320 and PURB. Mechanistically, LINC01320 could recruit PURB to the promoter region of DDB2 to repress DDB2 transcription; thus, promoting the expression of NEDD4L and impeding the TGF-β/SMAD signaling pathway, and ultimately facilitating the progression of OC. Finally, rescue experiments confirmed the involvement of the DDB2/NEDD4L/TGF-β axis in LINC01320-mediated OC progression. In conclusion, this study unveils for the first time the pivotal function of the LINC01320/PURB/DDB2/NEDD4L/TGF-β axis and explores its prospective clinical implications in OC.