The present invention relates to compositions and methods for enhancing the oncolytic activity of replication-competent, target cell-specific adenovirus vectors by modification of the E1A gene product. The target cell-specific replication-competent adenovirus vectors comprise a chimera of an adenovirus gene essential for replication, preferably an early gene, and the Androgen receptor (or a portion thereof) under the transcriptional control of a cell type-specific transcriptional regulatory element (TRE). By providing for cell type-specific transcription through the use of one or more cell type-specific TREs, the adenovirus vectors effect prostate-specific cytotoxicity due to selective replication.