Oncogenic function of TUSC3 in non-small cell lung cancer is associated with Hedgehog signalling pathway.

Non-small cell lung cancer (NSCLC) represents 75-80% of all lung carcinomas, which is the most common cause of death from cancer. Tumour suppressor candidate 3 (TUSC3) is pivotal in many biochemical functions and cytological processes. Dis-regulation of TUSC3 is frequently observed in epithelial cancers. In this study, we observed up-regulated TUSC3 expression at the mRNA and protein levels in clinical NSCLC samples compared with adjacent non-tumorous lung tissues. The expression level of TUSC3 is significantly correlated with tumour metastasis and patient survival. Overexpression of TUSC3 in NSCLC cells led to increased proliferation, migration, and invasion in vitro and accelerated xenograft tumour growth in vivo, while the opposite effects were achieved in TUSC3-silenced cells. Increased GLI1, SMO, PTCH1, and PTCH2 abundance were observed in TUSC3 overexpressed cells using western blotting. Co-immunoprecipitation and immunofluorescence analyses further revealed interaction between TUSC3 and GLI1. In conclusion, our study demonstrated an oncogenic role of TUSC3 in NSCLC and showed that dis-regulation of TUSC3 may affect tumour cell invasion and migration through possible involvement in the Hedgehog (Hh) signalling pathway.