Human bone marrow mesenchymal stem cell-driven LncRNA PTCSC3 upregulation within lung adenocarcinoma cells reduces erlotinib resistance by mitigating Wnt/β-Catenin pathway

lncRNA PTCSC3, which stands for Papillary Thyroid Carcinoma Susceptibility Candidate 3, has been found to play a role in various cellular processes, including cell proliferation, apoptosis, and migration, acting as either an oncogene or a tumor suppressor depending on the context. This study investigates the influence of lncRNA PTCSC3, derived from human bone marrow mesenchymal stem cell (hBMSC), on the efficacy of erlotinib (Er)-resistant lung adenocarcinoma (LUAD) cells and elucidates underlying mechanism. The hBMSCs and LUAD (PC9 and A549) cells were employed to establish an Er-resistant LUAD cell model. It was observed that exposure to hBMSCs reduced the viability of A549-Er and PC9-Er cells and increased their rate of apoptosis. Further investigations revealed that in the presence of hBMSCs-containing medium, PTCSC3 expression was significantly upregulated, concomitantly with a suppression of the Wnt/beta-Catenin pathway. Conversely, silencing PTCSC3 led to enhanced A549-Er and PC9-Er activities, reduced cell apoptosis, and activated Wnt/beta-Catenin pathway. The effects of PTCSC3 modulation were also examined by transfecting LUAD cells with different PTCSC3 expression vectors and treating them with XAV939, a Wnt/beta-Catenin pathway inhibitor, which similarly decreased cell viability. In the rescue experiment, the effect of hBMSCs on LUAD cells could be counteracted by down-regulation of PTCSC3, and the effect of PTCSC3 down-regulation on cells was mitigated by XAV939. This study revealed that hBMSCs promote the up-regulation of PTCSC3 in LUAD cells, thus inhibiting Wnt/beta-Catenin pathway and reversing Er resistance, offering a potential novel strategy to enhance the efficacy of chemotherapy in LUAD.