Figure 4

Phosphorylation levels of STAT5, ERK1/2 and RPS6 in TKI-sensitive and -resistant cell lines. Cell lines were treated for 3 h with/without imatinib (200 nM). Phosphorylation of STAT5, ERK1/2 and RPS6 was determined by Western blot analysis. Note that imatinib spares or only marginally induces dephosphorylation of RPS6 in imatinib-resistant cell lines. ERK1/2 dephosphorylation is seen in most imatinib-resistant cell lines. Abbreviations: s TKI-sensitive; r TKI-resistant; sr semi-resistant.