BIRC6 mRNA, protein, and BIRC6 phosphopeptide are higher in imatinib resistant MYL-R cells.

<p>(A) Sequence and position of the BIRC6 phosphopeptide. (B) Short-term ponatinib treatment of MYL-R cells reduced BIRC6 phosphopeptide. The BIRC6 phosphopeptide was isolated from cell lysates of MYL, MYL-R, and MYL-R cells treated with 10 nM ponatinib or 0.1% DMSO for 1 hour. Label-free quantification of mass spectral data was done using MaxQuant and normalized to MYL. (C and D) Short-term ponatinib treatment suppressed Bcr-Abl and Lyn signaling in MYL-R cells. Total BIRC6 and Mcl-1 proteins were not affected. Immunoblot analyses of the same lysates were performed to validate changes in Bcr-Abl and Lyn observed from the MIB/MS data. (E and F) BIRC6 mRNA and protein were elevated in MYL-R cells compared to MYL and K562 cells. QRT-PCR and immunoblot analyses were performed as described in Materials and Methods on parental MYL, MYL-R, and K562 CML cell lines to examine BIRC6 expression. * Represents <i>p < 0</i>.<i>05</i>. Data are representative of three independent experiments.