SIRT1 and breast cancer: In contrast to previous reports that SIRT1 negatively regulates oncoprotein â-catenin in colon cancer [21] and survivin in breast cancer [30], in our studies SIRT1 overexpression induced increased â-catenin mRNA and protein expression, increased â-catenin TCF/LEF transcription co-activation and increased expression of â-catenin target genes cyclin D1 and survivin in liver tumor cells (Figure S2).