Effects of stromal cells on sentitivity to imatinib in Sup-B15 Philadelphia chromosome positive acute lymphoblastic leukemia cells / 中华血液学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the sensitivity of imatinib (IM) on Sup-B15 Ph+ acute lmphoblastic leukemia (ALL) cells indused by stromal cells OP9, and to further explore its mechanism.</p><p><b>METHODS</b>The study is divided into two group, Sup-B15 cells group and co-cultured with OP9 cells group (Sup-B15/OP9 group). The inhibitory effects of IM on leukemia cells were measured by CCK-8 test, and the apoptosis by Annexin Ⅴ/7-AAD dyeing and the percentage of CD 34+CD38- leukemia cells were determined by flow cytometry. ALDH1, CD144, and β-catenin mRNA were detected by real-time RT-PCR, protein levels by Western blot. Inmunoprecipitation was used to detect the level of β-catenin connected to CD144.</p><p><b>RESULTS</b>IM presented inhibitory effects on Sup-B15 and Sup-B15/OP9 cells at multiple concentrations from 10 μmol/L to 45 μmol/L. The IC50 of IM on Sup-B15/OP and Sup-B15 cells were 35.8 μmol/L and 6.3 μmol/L, respectively (P<0.05). After 24 h of 30 μmol/L IM treatment, the percentages of apoptosis cells in Sup-B15/OP9 and Sup-B 15 cell were (14.24 ± 2.11)% and (3.45 ± 0.68)%, respectively (P<0.05). The percentage of CD34+CD38- cells in Sup-B15/OP9 group was significantly higher than that in Sup-B15 group [(3.42 ± 0.28)% vs (0.16 ± 0.15)%, P<0.05]. As compared to Sup-B15 cells, the transcription of ALDH1 in Sup-B15/OP9 group was remarkably upregulated (0.097 ± 0.012 vs 0.046 ± 0.010, P<0.05), and the CD133 protein level was also upregulated in Sup-B15/OP9 group. The transcription of CD144 in Sup-B15/OP9 group was remarkably upregulated compared with Sup-B15 group (0.103 ± 0.015 vs 0.010±0.003, P<0.05), as well as the CD144 protein. β-catenin mRNA transcription has no obvious changes between Sup-B15 group and Sup-B15/OP9 group (P>0.05), while the whole β-catenin protein and the cell nucleus β-catenin significantly increased, as well as the β-catenin protein combined with CD144.</p><p><b>CONCLUSION</b>Co-cultured with OP9 cells, Sup-B15 cells show less sensitivity to imatinib. The raising activity of CD144 and CD144/β-catenin signaling may work in this procession.</p>