XPO1 expression is enhanced in Ph⁺ acute leukemia (CML-BC and B-ALL) progenitors. (A) Top right panel: XPO1 and BCR-ABL1 protein levels in BCR-ABL1- or empty vector–transduced 32Dcl3 myeloid cells were determined by immunoblot. Left panel: Protein levels of XPO1 expressed as mean ± standard error of the mean (SEM) of densitometric units after normalization with Grb2 levels, were determined by immunoblot of NBM (n = 7), CML-CP (n = 3), and CML-BC (n = 7) CD34⁺ progenitors, and Ph⁺ B-ALL (n = 5) and Ph⁻ B-ALL (n = 4) CD34⁺/CD19⁺ progenitors. Bottom right panel: Sample of immunoblots used to determine XPO1 protein levels used for quantification. (B) Left panel: XPO1 protein levels expressed as mean ± SEM in vehicle- or imatinib-treated (1 µM, 12 hours) CML-BC CD34⁺ cells and Ph⁺ B-ALL CD34⁺/CD19⁺ cells. Right panel: Representative immunoblot of XPO1 protein levels and BCR-ABL1 activity (anti-PY) in vehicle- or imatinib-treated (1 µM, 12 hours) Ph⁺ B-ALL CD34⁺/CD19⁺ (lanes 1 and 2) and CML-BC CD34⁺ (lanes 3 and 4) cells. (C) Left panel: XPO1 protein levels in 32D-BCR/ABL cells treated (24 hours) with the indicated kinase inhibitors. Right panel: XPO1 mRNA levels assessed by quantitative reverse-transcription PCR in 32Dcl3 and untreated and kinase inhibitor–treated (24 hours) 32D-BCR/ABL cells. Asterisks indicate P values vs NBM; *P < .05, **P < .01.