Expression and Function of C1orf132 Long-Noncoding RNA in Breast Cancer Cell Lines and Tissues

miR-29b2 and miR-29c play a suppressive role in breast cancer progression. C1orf132 (also named MIR29B2CHG) is the host gene for generating both microRNAs. However, the region also expresses longer transcripts with unknown function. We employed bioinformatics and experi-mental approaches to decipher C1orf132 expression and function in breast cancer tissues. We also used the CRISPR/Cas9 technique to excise a predicted C1orf132 distal promoter and followed the behavior of the edited cells by real-time PCR, flow cytometry, migration assay, and RNA-seq tech-niques. We observed that C1orf132 long transcript is significantly downregulated in tri-ple-negative breast cancer. We also identified a promoter for the longer transcripts of C1orf132 whose functionality was demonstrated by transfecting MCF7 cells with a C1orf132 promoter-GFP construct. Knocking-out the promoter by means of CRISPR/Cas9 revealed no expression alteration of the neighboring genes CD46 and CD34, while the expression of miR-29c was reduced by half. Furthermore, the promoter knock-out elevated the migration ability of the edited cells. RNA se-quencing revealed many up- and downregulated genes involved in various cellular pathways, in-cluding epithelial to mesenchymal transition and mammary gland development pathways. Alto-gether, we are reporting here the existence of an additional/distal promoter with an enhancer effect on miR-29 generation and an inhibitory effect on cell migration. Overall design: RNA-seq transcriptome profiling of wild-type and C1orf132-edited MCF12A cells. 4 samples, 2 biological replicates for each condition.