Figure 4. Compound genetic deficiency of GSK3-α and GSK3-β impairs the growth and leukemogenicity of MLL-transformed cells.

a, Western blot analysis was performed on wild type (WT) and Gsk3b^−/− myeloid progenitors transformed by the indicated oncogenes (top) and transduced by lentiviral vectors lacking (−) or expressing (+) Gsk3a shRNA . b, Myeloid progenitors transformed by the indicated oncogenes were acutely transduced with lentiviral vectors lacking or expressing Gsk3a shRNA and then plated in methylcellulose medium. Colonies were enumerated after 5 days, and the mean (± s.e.m.) numbers of three independent determinations are expressed relative to vector alone. c, Proliferation of myeloid progenitors (WT, Gsk3b^−/− or Gsk3b^−/− Gsk3a^KD) transformed by MLL–ENL (left panel) or NUP98–HOXA9 (right panel) was assessed at the indicated days in liquid culture (± s.e.m. of triplicate analyses). d, The morphological features of MLL–ENL transformed myeloid progenitors with the indicated genotypes were assessed after 4 days of culture. The bar graph indicates the mean number of cells with the indicated morphological features (n = 3). e, Survival curves are shown for cohorts of mice transplanted with cells (WT, Gsk3b^−/− or Gsk3b^−/− Gsk3a^KD) stably transduced with MLL–ENL (10 mice each). f, Cell numbers were determined after 3 days of culture in the indicated concentrations of lithium chloride. g, Survival curves show significantly different latencies (P < 0.001) for the development of acute leukaemia in cohorts of mice transplanted with MLL–AF4 leukaemia cells (5 × 10⁴) and maintained on normal or lithium carbonate (0.4%) laced chow as indicated.