The invention provides adenoviral vectors (preferably replication competent)
comprising both an E3 sequence and at least one adenoviral gene under transcriptional
control of a target cell-specific transcriptional response element. These vectors
display significantly improved cytotoxicity, which is especially useful in the
cancer context, in which selective destruction of target cells is desirable. The
invention further provides host cells comprising the vectors. The invention further
provides methods of using the adenoviral vectors.