FIGNL1 promotes non-small cell lung cancer cell proliferation

Lung cancer is the most frequently diagnosed cancer and the leading cause of cancer-associated mortality worldwide. In the present study, a novel molecular therapeutic target for lung cancer was investigated. The protein expression level of fidgetin-like 1 (FIGNL1) in human lung cancer tissues was determined and its potential functions in the H1299 and A549 lung cancer cell lines was subsequently studied. In addition, the protein expression level of FIGNL1 in 109 lung cancer samples and corresponding para-cancerous tissues was investigated, using immunohistochemical staining. RNA interference and overexpression of FIGNL1 was used to determine the role of FIGNL1 in regulating cell proliferation, and cDNA microarray analysis was performed to identify the potential regulatory pathways. Lastly, the potential role of FIGNL1 in regulating tumorigenesis in lungs and also the proliferation of lung cancer cells was investigated. Firstly, lung cancer tissues were found to express higher protein levels of FIGNL1 and was significantly associated with decreased cell proliferation, migration and invasion abilities, and enhanced cell death. Overexpression of FIGNL1 significantly promoted cell proliferation, including decreased arrest at the G(1) phase of the cell cycle and apoptosis, as well as increased ability for fission and migration. These in vitro findings were consistent with the results of the cell-line derived xenografts in BALB/c nude mice, where tumor growth was decreased when injected with cells transfected with shFIGNL1. Collectively, these results provide suggest that FIGNL1 is involved in cell growth and tumorigenesis.