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Objective: 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., Methods: 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., Results: 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., Conclusion: 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.

Objective: To observe the efficacy of high-dose dexamethasone in combination with low-dose rituximab as a second-line treatment for patients with immune thrombocytopenia (ITP)., Methods: 65 patients with ITP, previously by conventional dose of glucocorticoids, received high-dose dexamethasone in combination with low-dose rituximab (dexamethasone 40 mg/d for 4 days, rituximab 100 mg, d 7, 14, 21, 28 intravenous infusion). Treatment response, regulatory T cells (Treg), cytokines levels and treatment-related adverse effects were observed., Results: Total response rate 1 month after treatment was achieved in 81.5% (53/65) of patients, and complete response at 3,6 and 12 months was 72.3% (47/65), 66.2%(43/65), 63.1%(41/65). The higher efficiency and complete response rate was achieved in preexisting glucocorticoid-dependent patients. For patients with complete response, Treg cells continued to show a high level state [(3.01 ± 0.95)% vs (1.69 ± 0.35)%, P=0.032], cytokines of BAFF [(648.03 ± 79.63) ng/L vs (972.35 ± 93.64) ng/L, P=0.001], IL-2 [(2.84 ± 0.32) ng/L vs (4.18 ± 0.46) ng/L, P=0.012], sCD40L[(4.55 ± 0.66) ng/L vs (7.73 ± 1.04) ng/L, P=0.006] significantly lower than that before treatment. The level of IL-10 was increased, but without significance compared with that before treatment (P=0.136). All patients completed the protocol with no serious adverse reactions., Conclusion: The data show high-dose dexamethasone in combination with low-dose rituximab still has a satisfactory outcomes for patients previously with conventional dose of glucocorticoid.

Objective: To investigate the effect of bromdomain protein 4 (BRD4) inhibitor GSK525762A on the proliferation, apoptosis of B-cell acute lymphoblastic leukemia cell line RS4;11 cells, and to further explore the mechanism., Methods: Compared with Jurkat leukemia cells, the activity of BRD4 on RS4; 11 cells were inhibited by the inhibitor GSK525762A. The inhibitory effects of BRD4 on RS4; 11 cells were measured by CCK-8 test and the apoptosis of those cells was determined by AnnexinV/7-AAD dyeing using flow cytometry. The transcripts of anti-apoptotic genes c-myc, Bcl-2, CDK6 and proapoptotic genes Bad, Bak, Bax were detected by quantitative PCR, and the expression of Bcl-2 and Bak proteins were detected via Western blot., Results: Proliferation of RS4;11 cells could be inhibited by GSK525762A in a time- and dose-dependent manner, and the inhibitory IC50 at 48 and 72 h was 6.174 and 1.996 μmol/L, respectively. Compared with DMSO in control group, the levels of c-myc, Bcl-2 and CDK6 mRNA transcripts in RS4; 11 cells were reduced in GSK525762A treated group, while the levels of Bad, Bak, Bax mRNA transcripts were enhanced,moreover, Bcl- 2 protein levels decreased and Bak protein levels increased. However, the inhibitory effect of GSK525762A on Jurkat cells proliferation was not obvious., Conclusion: GSK525762A can inhibit the proliferation of RS4; 11 cells and promoted cells apoptosis. The possible mechanisms underlying this phenomenon might be achieved via downregulation of Bcl-2 protein induced apoptosis of leukemia cells.