A. RAW264.7, MEF-1, and B16F10 cells, which had been transfected with the indicated plasmid (2 μg/100 mm dish), were co-cultured in Boyden chambers (stromal cells in the upper chamber and cancer cells in the lower chamber). B. Human ovarian cancer cells (SKOV3 and SNU840) and human fibroblasts (CCD18Lu), which had been transfected with the indicated plasmids, were co-cultured in Boyden chambers. C. B16F10, SKOV3, SNU840, MEF-1, and CCD18Lu cells, which had been transfected with the indicated siRNAs (80 nM), were co-cultured in Boyden chambers. Cell growth was analyzed using MTT. Data (mean ± s.d.; n=4) are plotted as a function of incubation time. *, p < 0.05. P, +S, N, and -S denote the transfection with pcDNA, SIRT1 plasmid, non-targeting RNA, and SIRT1-targeting siRNA, respectively.