Anguilla japonica lectin 1 delivery through adenovirus vector induces apoptotic cancer cell death through interaction with PRMT5. BACKGROUND:  Our previous studies have demonstrated that, through adenovirus mediated gene delivery, various exogenously expressed lectins elicited cytotoxicity to cancer cells, utilizing protein arginine methyltransferase 5 (PRMT5) as a common binding target. METHODS:  In the present study, a FLAG tagged Anguilla japonica lectin 1 (AJL1) expression cassette was genetically harbored in a replication-defective adenovirus genome, forming Ad.FLAG-AJL1. The exogenous AJL1-induced cytotoxicity and the underlying mechanisms were analyzed. RESULTS:  The exogenous AJL1 suppressed the proliferation of a variety of human cancer cells by inducing apoptosis. Caspase 9, Bcl-2, X-linked inhibitor of apoptosis protein, mitogen-activated protein kinase kinase 1/2-extracellular signal-regulated kinase and p38 mitogen-activated protein kinase were found to be responsible for the exogenous AJL1-induced cytotoxicity. AJL1 was further suggested to regulate PRMT5-E2F-1 pathway, a pathway shared by previously reported marine lectins Dicentrarchus labrax fucose binding lectin and Strongylocentrotus purpuratus rhamnose binding lectin. A localization study revealed that exogenous AJL1 widely distributed in the cell membrane and cytoplasm. CONCLUSIONS:  The results of the present study suggest that the PRMT5-E2F-1 pathway may act as a common target for exogenous lectins including AJL1, and the cellular response to exogenous AJL1 may suggest a novel agent for cancer gene therapy. Copyright © 2016 John Wiley & Sons, Ltd.