Linc-Pint Long Non‑Coding RNA Sponges miR‑7 and Regulates WNT Signaling Pathway in Breast Cancer Cells

Abstract

\n Several non-coding RNAs (ncRNAs) are known to regulate signaling pathways in breast cancer (BC) to date. Looking for the differentially expresses lncRNAs, first, RNAseq data analysis indicated that Linc-Pint (Loc646329) gene is downregulated in BC tissues. Consistently, RT-qPCR analysis confirmed its downregulation in BC specimens compared with normal pairs. Then, overexpression of Linc-Pint in MCF7 cells was followed by elevated APC, APC2, and Axin genes expression (all tumor suppressors of Wnt signaling), while c-Myc, CCND1 and CCND2 genes were downregulated, detected by RT-qPCR. Consistently, Top/Fop flash assay supported Linc-Pint suppressive effect on Wnt signaling in MCF7 cells. On the other hand, miR-7 was predicted to be sponged by Linc-Pint and clash-Seq data analysis supported their interaction. Furthermore, dual luciferase assay verified their interaction and consistently, overexpression of Linc-Pint ended in elevated expression level of TGFBR2 and IGF1R (as target genes of miR-7). Flow cytometry results indicated that Linc-Pint overexpression in MCF7 cells was followed by cell cycle arrest at G1 phase and scratch test assay supported its inhibitory effect on cell migration. Overall, our results indicated that Linc-Pint tumor suppressor attenuates Wnt signaling at least by sponging miR-7 in MCF7 cells. This makes Linc-Pint transcript as a potential new therapeutic target.