This invention relates to regulation of cell signaling, cell growth, and more particularly to the regulation of cancer or inflammatory cell growth and/or activation. The invention provides methods of, and compositions useful for, inhibiting interactions between MUC1 and a kruppel-like factor (KLF), method of inhibiting interactions between a KLF protein and the p53 promoter, methods of inhibiting the interaction between MUC1 and the p53 promoter, methods of increasing p53 activity, and methods of increasing histone acetylation. The invention also provides screening methods for identifying compounds that inhibit the aforementioned interactions. Pharmaceutical compositions containing the identified compounds can be useful in treating cancers and inflammatory conditions.