A Novel ceRNET Relying on the lncRNA JPX, miR-378a-3p, and Its mRNA Targets in Lung Cancer

Simple Summary Non-coding RNAs, particularly microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), are emerging as a driving force for lung cancer, the leading cause of cancer-related death. In this experimental work, we unveiled a novel competing endogenous RNA network (ceRNET) involving the lncRNA JPX, miR-378a-3p, and its downstream oncogenic targets in lung adenocarcinoma cells. First, a reverse expression pattern of JPX and miR-378a-3p was found in tumor tissues compared to normal lungs; subsequently, physical interaction between the molecules was demonstrated. Then, the boosting of either JPX or/and miR-378a-3p levels in lung cancer cells demonstrated the oncogenic role of JPX, the oncosuppressive function of the miRNA, and their functional relationship using an array of biological assays evaluating cell proliferation, migration, invasion, and 3D-spheroid formation. Finally, the ability of JPX to inhibit the silencing activity of miR-378a-3p toward its targets GLUT1, NRP1, YY1, and Wnt5a, and thus the contribution to lung cancer, was demonstrated.Abstract Lung cancer is the leading cause of cancer-related death worldwide. Non-coding RNAs are emerging as critical players for the onset and progression of cancer. Analyses of three different datasets revealed that the lncRNA JPX was overexpressed in adenocarcinoma tissues in comparison to normal lungs, as expected for an oncogene. Intriguingly, the predicted binding miR-378a-3p showed a significant inverse correlation with JPX expression. The lncRNA/miRNA physical interaction was validated by reporter vectors. Then, the oncogenic activity of JPX, the tumor-suppressive role of miR-378a-3p, and the contribution of their functional interaction to cancer hallmarks were demonstrated using assays for cell proliferation, migration, invasion, and 3D-spheroid formation. Finally, molecular circuits were investigated by boosting the expression of both JPX and miR-378a-3p, singularly and in combination, demonstrating that JPX counteracted miR-378a-3p silencing activity toward its oncogenic targets GLUT1, NRP1, YY1, and Wnt5a. Overall, the data unveil a novel ceRNET (competing endogenous RNA network), wherein JPX acts as a ceRNA by binding to miR-378a-3p, thus reducing the miRNA silencing activity toward its downstream targets, and eliciting oncogenic pathways driving lung cancer. The knowledge of the network may pave the way to develop new diagnostic panels, and innovative RNA-targeted and RNA-based therapeutic strategies.