NFYC-AS1 antisense lncRNA as a potential novel player in cell cycle regulation in human cancer

NFY is a pioneer transcription factor that in physiological conditions drives the transcription of a plethora of cell-cycle regulatory genes, thus acting as a master regulator of proliferation. It is a heterotrimer composed of NFYA, NFYB, and NFYC subunits, which acts by binding to CCAAT-boxes on the DNA. Notably, CCAAT-boxes are overrepresented in promoters of genes upregulated in diverse types of human cancer and a multitude of NFY-regulated genes are overexpressed in tumor cells to mediate cell growth and metabolism, thus suggesting that increased NFY activity may have a role in tumorigenesis. Different layers of regulation were shown to tune NFY expression, however post-transcriptional mechanisms have been so far poorly investigated, especially about the role of noncoding RNAs. In this regard, the function of a peculiar antisense lncRNA transcribed head-to-head to NFYC, the so called NFYC-AS1, is completely unexplored. We found that NFYC-AS1 (and not its sense gene NFYC) is overexpressed in most human tumors compared to normal tissues, among which lung adenocarcinoma and squamous cell carcinoma, the main histotypes of non-small cell lung cancer. Analyses are ongoing to define the exact structure of NFYC-AS1 transcript(s), its biological function and mechanisms of action (in cis vs in trans). Our preliminary functional data show that NFYC-AS1 is prevalently nuclear and that its knock-down in squamous cell carcinoma cells, obtained by using gapmer antisense oligonucleotides targeting different regions of the transcript, leads to alterations of cell cycle related pathways. Accordingly, NFYC-AS1 silencing reduces cell growth in a time-dependent manner. Moreover, experiments of cell cycle re-entry show a rapid increase in NFYC-AS1 levels at the very beginning of G1 phase. Altogether, our findings indicate a possible involvement of NFYC-AS1 in supporting cancer cell proliferation. Current efforts are aimed at developing innovative CRISPR approaches to modulate NFYC-AS1 expression and fully characterize its mechanism of action.