Smad7-overexpressing BM cells exhibit reduced proliferative and clonogenic capacity in vitro. (A) BM cells were sorted for GFP directly after transduction and plated in serum-free media. Cells were counted and replated every third day. Day 0 indicates day of sorting. Data represent fold increase in number of cells ± SEM from 4 separate experiments (P ≤ .03 for days 6, 9, and 12). (B) Cells from the liquid culture were plated at indicated days into methylcellulose supporting growth of CFU-GM colonies. Data represent number of colonies/1000 input cells on day 0. Mean values ± SEM (P = .02 day 12). (C) BM cells were sorted for GFP directly after transduction (day 0) and plated onto preseeded sl/sl stromal cells in serum-free media. BM cells were counted and replated every third day for up to 12 days after transduction. Data represent mean values of fold expansion of number of cells ± SEM (n = 3). No significant differences in growth were detected between MIG and Smad7 on sl/sl stroma on days 9 and 12 (P > .05). Also included in the graph is Smad7-overexpressing cells grown under stroma-free conditions (n = 4).