Fig. 2 | Leukemia

Fig. 2

From: The phosphatase UBASH3B/Sts-1 is a negative regulator of Bcr-Abl kinase activity and leukemogenesis

Fig. 2

Sts-1 negatively regulates Bcr-Abl-dependent leukemogenesis and cell proliferation and its expression is upregulated by dexamethasone. a The proliferation competition assay with Ba/F3 cell transduced with BCR-ABL1 wt or T315I in the absence or presence of STS-1 expression and without (left) or with (right) imatinib treatment (2 µM). BCR-ABL1-positive cells are marked with GFP and the relative changes in GFP expression were measured by FACS and followed over time. Mean values ± SD from three replicates are shown.b Equal amounts of primary murine Lin c-Kit+ Sca-1+ cells from wt or Sts-1/Sts-2 knockout animals expressing BCR-ABL1 were injected in lethally irradiated recipient mice (n = 8 for each group). Overall survival of transplanted mice was monitored over 60 days. P-value = 0.014 was calculated using a logrank (Mantel–Cox) test. Representative spleens from control mice, BCR-ABL1/Sts-1/2 wt and BCR-ABL1/Sts-1/2 KO mice are shown. c SupB15 Ph+ ALL cells and their imatinib-resistant subline SupB15RT were exposed to 10−7 M dexamethasone, and STS-1 expression was investigated at the given time points. α-Tubulin was used as loading control. d SupB15 Ph+ ALL cells and their imatinib-resistant subline SupB15RT were exposed to 10−7M dexamethasone, and the effect of increasing expression of STS-1 on BCR-ABL1 phosphorylation was investigated by an anti-p-Tyr antibody. e SupB15 and SupB15RT were exposed to imatinib (1 µM) and 10−7M dexamethasone alone or in combination and proliferation was analyzed by the XTT assay. The bars represent the mean (±SEM) of three independent experiments, each performed in triplicates. Statistical significance was calculated using student’s t test. ***p ≤ 0.001

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