Paired-like homeodomain 2B contributes to tumour progression and anti-autophagy in human lung cancer.

Paired-like homeodomain transcription factor 2 () is well known to play an essential role in normal embryonic development. Emerging evidence suggests that may be involved in human tumorigenesis, but the role of in tumour progression remains largely unclear. The expression levels of in lung cancer cells were determined by qRT-PCR and Western blot analyses. Gain- and loss-of-function experiments were conducted to investigate the biological roles of in the phenotype of lung cancer cells. Immunofluorescence staining and transmission electron microscopy were used to observe autophagy. The expression level and clinical significance of were determined in a Taiwanese cohort and the Gene Expression Omnibus (GEO) database, respectively. Here, we show that is the most abundant isoform of the bicoid homeodomain family in lung cancer cells. The enforced expression of PITX2B promoted lung cancer tumorigenesis and progression and . The mechanistic analysis revealed that the nuclear localization of PITX2B is correlated with its oncogenic functions and two important nuclear localization signals. In addition, knockdown in lung cancer cells caused a marked increase in autophagy and apoptosis, suggesting that PITX2B plays an important role in lung cancer cell survival. Moreover, a high expression of was associated with a poor overall survival (<0.05) in both Taiwanese non-small-cell lung cancer patients and GEO lung cancer cohorts. These results provide new insight into the contribution of to lung cancer progression, implicate PITX2B as an important component of cell survival signals and further establish as a therapeutic target for lung cancer treatment.