Long Noncoding RNA CPS1-IT1 Suppresses Cell Proliferation and Metastasis in Human Lung Cancer

The long noncoding CPS1 intronic transcript 1 (lncRNA CPS1-IT1) is a recently identified tumor suppressor in the lncRNA family of proteins. Whether this lncRNA plays any functional role in solid tumors remains largely unknown. The present study aimed to investigate the role of lncRNA CPS1-IT1 in human lung cancer. Expression of lncRNA CPS1-IT1 was initially assessed in human lung cancer and in a series of lung cancer cell lines. The effects of CPS1-IT1 overexpression on cell proliferation, migration, and invasion were examined in lung cancer cell lines A549 and 95D. It was found that lncRNA CPS1-IT1 was significantly lower in cancerous tissues than in noncancerous tissues. lncRNA CPS1-IT1 was differentially expressed in lung cancer cell lines and expressed the least in two highly invasive cell lines, A549 and 95D. Overexpression of CPS1-IT1 slowed down cell proliferation by 35.7% in A549 cells and 30.8% in 95D cells on the fifth day. Cell migration was inhibited by 59% in A549 cells and 48% in 95D cells, and cell invasion was suppressed by 60% in both cell lines after overexpression of CPS1-IT1. While cell apoptosis was induced, CPS1-IT1 overexpression promoted the activities of caspase 3 and caspase 9 without affecting that of caspase 8. These observations were suggestive of the tumor-suppressive role of lncRNA CPS1-IT1 in lung cancer. Our data suggest that CPS1-IT1 may be used as a biomarker for early diagnosis and therapeutic targets against lncRNA and may be promising in the treatment of lung cancer.