Human/Mouse STAT5a Antibody

Detection of Mouse STAT5A by Western Blot

Effects of inhibition of IGF-IR on IGF-IR, BCR-ABL and downstream target proteins in CML cell lines. (A) PPP induces concentration-dependent decrease in IGF-IR tyrosine kinase activity in K562 and KBM-5 cell lines. In contrast, PPP fails to cause similar effect in BCR-ABL tyrosine kinase activity. The results represent the means ± S.D. of three consistent experiments. *: P < 0.01 and †: P < 0.001 compared with control untreated cells. (B) Western blotting and co-immunoprecipitation studies confirm that PPP decreases the tyrosine phosphorylation of IGF-IR in a concentration-dependent fashion (results shown are representative and were obtained from the KBM-5 cell line). The basal levels of IGF-IR did not change after treatment with PPP. The phosphorylation level of BCR-ABL remains unchanged after treatment with PPP. The decrease in pIGF-IR is associated with down-regulation of pAkt and pSTAT5, two oncogenic proteins in CML. Changes are not seen in Akt and STAT5. Also, PPP induces changes consistent with apoptotic cell death including down-regulation of Bcl-2, Bcl-XL and caspase-3. Moreover, treatment with PPP induces up-regulation of cyclin B1 and down-regulation of cyclin E and pCdc2, whereas the levels of Cdc2 and p16 remain unchanged. Overall, the changes in the cell cycle regulatory proteins are consistent with G2/M-phase cell cycle arrest. beta-Actin shows equal loading of the proteins. (C) IGF-IR siRNA decreases IGF-IR levels in the KBM-5 cell line and this decrease is associated with down-regulation of pAkt and pSTAT5. Basal levels of these two proteins remain unchanged. IGF-IR siRNA did not induce alterations in BCR-ABL or pBCR-ABL protein. beta-Actin confirms equal loading of the proteins. Image collected and cropped by CiteAb from the following publication (https://pubmed.ncbi.nlm.nih.gov/19508387), licensed under a CC-BY license. Not internally tested by R&D Systems.