Abstract: Embodiments of the present disclosure pertain to compositions that include a compound that inhibits the histone acetyl transferase activity of a protein, such as p300 and/or CBP. Further embodiments of the present disclosure pertain to methods of inhibiting the histone acetyl transferase activity of a protein by exposing the protein to a composition that contains one or more of the compounds of the present disclosure. The compositions of the present disclosure may be exposed to a protein in vitro or in vivo. Additional embodiments of the present disclosure pertain to methods of treating a cancer in a subject by administering a composition of the present disclosure to the subject in order to treat the cancer.