NFATC3-PLA2G15 fusion transcript identified by RNA sequencing promotes tumor invasion and proliferation in colorectal cancer cell lines

Purpose :This study was designed to identify novel fusion transcripts (FTs) and their functional significance in colorectal cancer (CRC) lines. Materials and Methods: We performed paired-end RNA sequencing of 28 CRC cell lines. FT candidates were identified using TopHat-fusion, ChimeraScan, and FusionMap tools and further experimental validation was conducted through reverse transcription-polymerase chain reaction and Sanger sequencing. FT was depleted in human CRC line and the effects on cell proliferation, cell migration, and cell invasion were analyzed. Results: One thousand three hundred eighty FT candidates were detected through bioinformatics filtering. We selected six candidate FTs, including four inter-chromosomal and two intra-chromosomal FTs and each FT was found in at least one of the 28 cell lines. Moreover, when we tested 19 pairs of CRC tumor and adjacent normal tissue samples, NFATC3-PLA2G15 FT was found in two. Knockdown of NFATC3-PLA2G15 using siRNA reduced mRNA expression of epithelial-mesenchymal transition (EMT) markers such as vimentin, twist, and fibronectin and increased mesenchymal-epithelial transition markers of E-cadherin, claudin-1, and FOXC2 in colo-320 cell line harboring NFATC3-PLA2G15 FT. The NFATC3-PLA2G15 knockdown also inhibited invasion, colony formation capacity, and cell proliferation. Conclusion: These results suggest that that NFATC3-PLA2G15 FTs may contribute to tumor progression by enhancing invasion by EMT and proliferation.