Knockdown of Long Noncoding RNA PCAT6 Inhibits Proliferation and Invasion in Lung Cancer Cells

As a newly identified oncogenic long noncoding RNA (lncRNA), prostate cancer-associated transcript 6 (PCAT6) promoted cellular proliferation and colony formation of prostate cancer. However, the biological function of PCAT6 in lung cancer is still largely unknown. In this study, we found that PCAT6 is significantly increased in cancer tissues compared to normal tissues and positively correlates with metastasis of lung cancer in patients. We then examined PCAT6 expression in lung cancer cell lines and identified that PCAT6 expression was significantly elevated in lung cancer cells compared to normal human bronchial epithelial (NHBE) cells, especially in CL1-5 and H446 cells. PCAT6 knockdown significantly inhibited cellular proliferation and metastasis, as well as induced early apoptosis of lung cancer cells. Molecular analysis revealed that PCAT6 regulated the expression of two pivotal cancer-related proteins, c-Myc and p53, in lung cancer cells. However, PCAT6 was not directly combined with c-Myc and p53 as confirmed by RNA immunoprecipitation. Finally, a retrospective study further revealed that PCAT6 negatively correlates with overall survival of lung cancer patients. In conclusion, these results suggest that PCAT6 could play an oncogenic role in lung cancer progression and may serve as a biomarker for prognosis of lung cancer patients.