Embodiments of the invention employ methods and compositions for enhancing potency of immune cells that express one or more therapeutic proteins. In certain cases, the methods modulate expression of a CAR transgene in an immune cell, such as a T cell. Specific embodiments employ the exposure of cells and/or individuals to be treated with the cells with an effective amount of at least one agent that upregulates expression of the therapeutic protein, such as a mitogen, histone deacetylase inhibitor, and or DNA methyltransferase inhibitor.
