| dc.description.abstract | High-grade serous ovarian cancer (HGSOC) accounts for ~70% of ovarian cancer deaths. Current treatment regimens remain unchanged these last 3 decades. Neither has the introduction of PARP inhibitors improved overall patient survival. There is an urgent unmet need to further understand mechanisms contributing to disease progression. Long non-coding RNAs (lncRNAs) are crucial in tumourigenesis, yet their functions remain poorly understood in HGSOC. We sought to identify and characterise HGSOC-associated lncRNAs using in silico and in vitro techniques. Our discovery dataset comprised whole-transcriptome RNA-Seq data from 35 metastasis HGSOC omental biopsies. Following, de novo transcript assembly, we identified 1523 annotated and 393 novel lncRNAs. We compared lncRNA expression profiles of each sample to its mechanically determined disease score, identifying 119 disease-associated lncRNAs. Using laser capture microdissected samples (n=2 paired), we characterised 10 tumour-enriched and 69 stromal-enriched lncRNAs. Using TCGA data (n=374), we validated 25 clinically relevant, disease-associated cell type specific lncRNAs. We selected the tumour-enriched FAM86C2P lncRNA, for HGSOC characterisation. FAM86C2P is a 13.7kb transcribed unprocessed pseudogene lncRNA. FAM86C2P’s function is poorly understood, moreover, we reported for the first-time its potential tumour-promoting role in HGSOC. FAM86C2P localised to both cytoplasm and nucleus in HGSOC cell lines, using FISH and fractionation. We used RNAi and gapmeR loss-of-function methods to determine cytoplasmic and nuclear FAM86C2P’s gene pathway targets, respectively. RNA-Seq results showed that cytoplasmic FAM86C2P inhibited RNASEH2A, which is vital in the DNA repair pathway. Additionally, our RT-qPCR results showed that cytoplasmic FAM86C2P inhibited its parental homolog FAM86A /EEF2KMT, a methyltransferase that’s vital in translation. We reported for the first time a potential tumour promoting FAM86C2P/RNASHE2A regulatory axis in HGSOC. More work is required to determine FAM86C2P/RNASHE2A mechanism of action, signalling pathways and biological and clinical relevance, especially in DNA repair pathways, in addition to the potential role of EEF2KMT in this axis. | en_US |
