FIG. 8.

Plakoglobin enhances growth of the 32D hematopoietic progenitor cells. (a) The murine 32D cell line was stably transfected with a plakoglobin expression vector (pCGN-plakoglobin). Single clones were expanded and tested by Western blotting for plakoglobin expression. Levels of plakoglobin protein expression were comparable to those induced by AML1-ETO in U937 cells. (b) Plakoglobin-expressing 32D cells grew faster than their control vector-transfected counterparts. Shown are the means of three experiments. In each experiment, two independent cell lines each of the control- and the plakoglobin-transfected cells were analyzed. (c) Expression of plakoglobin in 32D cells was associated with increased proliferation, as shown by a [³H]thymidine incorporation assay. The plakoglobin effect was present at low as well as at high serum concentrations. The assay was independently performed three times. For each experiment, all conditions were tested in quadruplicate.(d) To analyze colony-forming abilities, control vector- or plakoglobin-expressing 32D cells were plated in colony assays. The number of colonies formed by plakoglobin-expressing cells was significantly higher than the number of colonies formed by control-transfected cells. Indicated are the mean and standard error of four different experiments performed with two independent control and plakoglobin cell lines each.