The role of Necl-5 in the invasive activity of lung adenocarcinoma

Nectin-like molucule-5 (Necl-5) is an immunoglobulin-like molecule that was originally identified as a poliovirus receptor and is often upregulated in cancer cells. It has been said that Necl-5 plays a role in not only cell–cell adhesion, but also cell migration, proliferation, and metastasis. In this study, we used a bronchioloalveolar carcinoma (BAC) cell line and fibroblasts to assess the expression of Necl-5 in the development of cancer–stroma communication by using an easy-to-prepare double-layered collagen gel hemisphere (DL-CGH) system that enables visualization of cell migration during invasion. The expression of Necl-5 was higher in BAC cells than in fibroblasts. This tendency didn't change even when the BAC cells were mixed with fibroblasts. To assess the role of Necl-5 in the invasive activity of the BAC cells, we knocked down its expression using RNA interference (RNAi). The invasion assay with DL-CGH revealed that inhibition of Necl-5 expression in the BAC cells was associated with suppressed invasiveness. In addition, Necl-5 knockdown inhibited the movement and proliferation of the BAC cells. Necl-5 expression in lung cancer cells is crucial for their invasiveness in the cancer–stromal interaction, suggesting that Necl-5 could be a favorable molecular target for the suppression of invasiveness in lung adenocarcinoma.