LRRC3B is downregulated in non-small-cell lung cancer and inhibits cancer cell proliferation and invasion.

LRRC3B has emerged as a tumor suppressor in several human cancers. However, its expression pattern and biological roles in human non-small-cell lung cancer (NSCLC) have not been explored. In the present study, we investigated clinical significance of LRRC3B in 101 NSCLC specimens. We found that LRRC3B expression was downregulated in NSCLC tissues compared with normal bronchial epithelium and that its downregulation significantly correlated with tumor-node-metastasis (TNM) stage (p < 0.0001), nodal metastasis (p < 0.0001), and poor patient prognosis (p = 0.0016, log-rank test). We also checked LRRC3B levels in several lung cancer cell lines and found that its expression was downregulated in four of nine lung cancer cell lines compared with normal human bronchial epithelial (NHBE) cell line. We further explored the biological role of LRRC3B. LRRC3B plasmid transfection in H460 and A549 cell lines inhibited proliferation, colony formation ability, and invading ability. Furthermore, we identified that LRRC3B could inhibit cell cycle progression with downregulation of cyclin D1 and decreased MMP9 expression. In addition, LRRC3B depletion in HBE cells promoted proliferation and invasion. In conclusion, our data suggested that LRRC3B may serve as an important tumor suppressor in NSCLC.