Objective To investigate the effect of histone deacetylase inhibitor LBH589 on proliferation,apoptosis and drug resistance of chemoresistant acute myeloid leukemia cells HL60/ADM.Methods HL60/ADM cells were treated with LBH589.Proliferation,apoptosis and adriamycin IC50 were evaluated by MTT assay and AnnexinV-FITC/PI stain.The change in MRP1 expression and intercellular adriamycin accumulatiom were analyzed by flow cytometry.Results Effective proliferative inhibition and apoptotic induction in HL60/ADM cells were observed after treatment with 10-80 nmol/L LBH589 with maximal effect detected after treatment with 70 nmol/L LBH589 for 60 hours.However,inhibition ratio remain unchanged with the further increase of drug dose and incubation time (P ＞ 0.05).Downregulation of MRP1 [(93.90±4.20) ％ vs (76.19±6.53) ％],upregulation of adriamycin accumulation [(8.53±0.68) ％ vs (25.67±1.34) ％] and decrease in adriamycin IC50 [(6.833±0.319) μg/ml vs (1.382±0.104) μg/ml] were induced by the treatment with 20 nmol/L LBH589 (P ＜ 0.01),whose reversal fold was 4.9.The expression of acetylated histone 3 after treatment with LBH589 was higher than that before treatment (P ＜ 0.01).However,relative p-Akt levels after treatment for 24 h and 48 h were 1.07±0.09 and 0.59±0.01,respectively,which were lower than that before treatment (2.03±0.12) (P ＜ 0.01).Meanwhile,expression levels of p53 were 0.57±0.04 and 1.31±0.09,respectively,which were higher than that before treatment (0.21 ±0.02) (P ＜ 0.01).Conclusion Treatment with LBH589 has the capability of inhibiting proliferation and inducing apoptosis,as well as increasing intercellular adriamycin accumulation and sensitivity through downregulation of MRP1 expression and inhibition of PI3K-Akt signaling pathway in HL60/ADM cells.

Heat shock protein A9 (HSPA9), a member of the heat shock protein family, is a putative receptor for Tembusu virus (TMUV). By using Western blot and co-immunoprecipitation assays, E protein domains I and II were identified as the functional domains that facilitate HSPA9 binding. Twenty-five overlapping peptides covering domain I and domain II sequences were synthesized and analyzed by using an HSPA9 binding assay. Two peptides showed the capability of binding to HSPA9. Dot blot assay of truncated peptides indicated that amino acid residues 19 to 22 and 245 to 252 of E protein constitute the minimal motifs required for TMUV binding to HSPA9. Importantly, peptides harboring those two minimal motifs could effectively inhibit TMUV infection. Our results provide insight into TMUV-receptor interaction, thereby creating opportunities for elucidating the mechanism of TMUV entry.
Blotting, Western ; Heat-Shock Proteins ; Hot Temperature ; Humans ; Immunoprecipitation ; Peptides ; Protein Structure, Tertiary