ALBERT

Description: This paper reports an investigation into palaeoflooding along the upper reaches of the Hanjiang River valley, China. Based on the sedimentary evidence of the palaeohydrological regime, two bedsets of palaeoflood slackwater deposits (SWDs) were identified interbedded within the Holocene loess–soil sequence along the riverbanks of the Ankang east reach. Optical Stimulated Luminescence (OSL) dating and stratigraphical correlation with previously dated sites were used to reconstruct the chronology of the palaeoflood events. The results show that the palaeoflood events represented by SWD1 occurred between 13 000 and 12 400 a, coincident with the climatic transition from the Bølling–Allerød (BL+AL) stage to the Younger Dryas (YD) event. The palaeoflood events recorded by SWD2 were dated to 1000–800 a, corresponding to the later stages of the North Song Dynasty (AD 960–1127) and the subsequent South Song Dynasty (AD 1127–1279), which was a time of climatic decline according to historical documents. Palaeoflood discharges were estimated using the step-backwater method, and the peak discharges were estimated to be in the range 35 200–47 400 m 3  s −1 . These results are of significance to our understanding of the regional hydrological response to global climatic change, the utilization of water resources, hydraulic engineering, flood control and disaster reduction.

Description: OBJIECTIVE To investigate the effect of apatinib, a small-molecule vascular endothelial growth factor receptor-2 tyrosine kinase inhibitor, on the proliferation and apoptosis of acute myeloid leukemia stem/progenitor like cell (kg1α) and its molecule mechanism. METHODS The kg1α cells were treated with a serial of concentrations of apatinib for 48 h and 72 h, the inhibitory ratio was measured by CCK8 assay, the apoptosis percent was measured by flow cytometry. Western bolt was used to analyzed AKT/p-AKT、p-Raf and p-PTEN expression after treatment with 0、10 and 20μM apatinib. RESULTS ①After treatment with a serial of apatinib (2.5、5、10、20、40μM) on AML stem-like cell line(kg1α)for 48 and 72 hours, the cell proliferation were significantly inhibited in a dose- and time-dependent mode. For treating with 48h, the cell viability were respectively (92.32±0.82) %、 (80.59±4.95) %、 (61.75±0.47) %、 (51.51±4.10) %、 (26.42±4.20) %, and all the differences had statistical significance compared with control group, and with the 50% inhibitory concentration(IC50) value of (16.98±0.08) μM; However, the viability were respectively (88.42±2.91) %、 (70.83±4.45) %、 (47.87±1.59) %、 (31.41±3.57) %、 (13.26±1.96) % for 72h, and with the 50% inhibitory concentration(IC50) value of (10.05±0.08) μM .②The results of Annexin V/PI showed that various concentration of apatinib induced significantly apoptosis on kg1α cells. After the treatment of 10、20、30 and 40μM apatinib for 48 hours, the apoptosis percentage was significantly higher than control group (6.12±1.26) %, respectively (4.57±1.16) %、 (12.6±2.34) %、 (16.37±4.38) % and (19.77±2.55) % ,and the differences(except for 10μM) had clearly significance compared with control group(F=18.85,P

Description: Acute myeloid leukemia is a heterogeneous hematopoietic neoplasia with a poor clinical outcome despite its treatment have made great progress in recent years. Strategies for targeting Bcl-2 using ABT-199 attract increasing attentions. however, most treatment failure strongly correlates with acquired up-regulation of MCL-1, which become the Achilles's heel of ABT-199 in clinical use. Here we describe low-cytotoxicity dosage of Chidamide (CS055), a novel selective HDACi designed in China, potentiated the cytotoxicity of ABT-199 towards diverse AML cell lines in vitro and primary samples obtained from patients with AML ex vivo, especially those carrying hyperleukocytosis, as well as highly active in vivo in a AML patient-derived xenograft murine model, while sparing normal peripheral blood mononuclear cells. Mechanistically, ABT-199/CS055-induced cytotoxicity was closely associated with inactivation of Mcl-1 and simultaneous induction of DNA damage accumulation. Of note, we also find a superior resensitization activity of CS055 in contrast with Romidepsin. In summary, our findings suggest that CS055 enhance the eliminating activity of ABT-199 towards AML cells, thus implying a highly promising and potent strategy for treatment of relapsed and refractory AML. Disclosures No relevant conflicts of interest to declare.

Description: Background The emergence of Imatinib has brought a new era for the treatment of chronic myeloid leukemia. However, resistant to Imatinib might lead to the treatment failure and death of patients. Thus, finding a drug which could enhance the Imatinib-induced apoptosis in vitro could provide the experimental base for the treatment of chronic myeloid leukemia. K562 cell line is a common cell line used in the study of chronic myeloid leukemia while K562/G cell line which is resistant to Imatinib is derived from K562 cell line. Aim This study aims to explore whether low-dose Triptolide(TPL) could enhance the Imatinib-induced apoptosis in K562/G cells and related mechanism. Methods K562/G cells were subjected to different treatments and thereafter MTT assay, flow cytometry and Western blot or RT-PCR were used to determine IC50, apoptotic status and expression of Nrf2, HIF-1α and their target genes. Results Triptolide is highly cytotoxic to K562/G cells in a concentration-dependent manner. To determine the combination effect of TPL and anticancer agents, K562/G cells were exposed to Imatinib(50μM) with or without TPL (25nM) for 24h. The apoptotic cells were determined by PI/Annexin V staining and flow cytometric analysis. Apoptotic ratio of cells treated by Imatinib together with TPL is significantly increased compared to cells treated by Imatinib alone (24.78±1.12 vs. 77.52±7.75, P

Description: Abstract 4340 Background: Myelodysplastic syndrome (MDS) is a malignant hematological disease that comprises a heterogeneous group of clonal hematopoietic stem and progenitor cell disorders, with peripheral cytopenias, bone marrow hypercellularity, high-risk of evolving into acute myeloid leukemia (AML). MDS/AML is a special refractory and palindromic AML characterized by poor therapeutic effects and low complete response rate, as well as high treatment-related complications and mortality. Patients with MDS/AML are often elders and represent more intolerance to routine or intensive chemotherapies. Homoharringtonine, an alkaloid found as the major active component in Chinese plants cephatotaxus fortuneif., has been widely used in AML since the 1970s in China. Decitabine, a hypomethylating agent, is active and has been approved for the treatment of myelodysplastic syndrome (MDS) in recent years. Objective: In order to compare the efficacy, toxicity and long-term prognosis of two chemotherapies HA (Homoharringtonine and cytarabine) and Decitabine regiment in MDS/AML. Methods: A total of 26 MDS/AML patients consisting of 14 males and 12 females were included in this study. They were randomly assigned to receive either HA (H 4mg.d−1,d1–3; A 100mg.m−2d−1, d1–7) or decitabine£.. 20mg.m−2d−1, d1–5£© The effect measures used were hazard ratios (HR) for overall survival (OS), progression-free survival (PFS) and freedom from first progression. Relative risks were used to analyse complete response rate, total response rate, treatment-related mortality and adverse events. A Log-rank test was used in survival analysis, and a Chi-square test was performed for other outcomes. Results: The complete remission (CR) rate with HA regimen according to MDS/AML criteria was 33% and 36% with decitabine (P〉0.05). HA group had no lower total response rate than Decitabine group (53% versus 64%, P〉0.05). The freedom from first progression in chemotherapy with HA regiment and decitabine was 20% and 18% (P〉0.05), respectively. PFS was not statistically significantly longer for two comparators with HR was 0.41(95% confidence interval (CI) 0.09722 to 1.740). There was no statistically significant difference in OS between the HA group and decitabine group with HR was 0.799 (95% CI 0.2992 to 2.133); median survival: 300 days vs 291 days (P〉0.05,95% confidence interval (CI) 0.6165 to 1.445). The treatment-related mortality was 13% with HA regimen versus 18% with decitabine at 3 weeks (P〉0.05) and 40% with HA regiment versus 18% with decitabine at 3 months (P〉0.05). The haematological toxicities and liver function lesion WHO grade III or IV were not significantly higher in the HA group than that in the decitabine group (P〉0.05). The total secondary infection rates in all sections of chemotherapies were 58% and 19% (P=0.005) in the two groups, respectively. Secondary infection rate was significantly lower in the decitabine group than that in the HA group. Conclusions: This analysis showed that Homoharringtonine and cytarabine regiment in treating MDS/AML has a similar therapeutic effect and long-term benefit with decitabine, both regiments were associated with relatively safe and effective outcomes in patients with MDS/AML. However, HA regiment shows a higher risk of secondary infection than decitabine. Longer follow-up and further studies will evaluate prospectively the results of HA regiment versus decitabine in this setting. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 4088 Backgrounds Acute myeloid leukemia(AML) is a hierarchical disease initiating from a rare population of cells known as leukemia stem cells (LSCs), which are typically enriched in CD34+CD38- cells and presumed responsible for the relapse and refractory of AML. Moreover, current regimens may not effectively discriminate between normal and malignant cells. For this reason, it is important to identify therapies that can specifically target the LSC population without affecting normal cells. Disulfiram (DS) is an anti-alcoholism drug that has recently been indicated to show cytotoxic to multiple cancers including acute myeloid leukemia (AML) and the antineoplastic activity was enhanced in the present of copper (Cu). In the present study, we investigated the effect of DS/Cu on LSCs and further explored its mechanism. Methods and Results CD34+CD38- leukemia stem cell (LSC) enriched subpopulations were sorted from both KG1a cell lines and primary AML bone marrow or peripheral blood mononuclear cells (n=6) by fluoresce-activated cell sorting (FACS) analysis. Using MTT cell proliferation assay and Annexin-V/PI staining assay, We demonstrated that DS/Cu inhibited proliferation and induced apoptosis in CD34+CD38−KG1a cells (IC50= 0.788± 0.451 μM at 24h). With the increasing concentrations of DS (DS=0.05, 0.5, 5, 50μM), the apoptotic proportion increased from 7.2% to 89.5% at 24h. Apoptosis was also observed in CD34+CD38- primary AML cells and the exposure to DS/Cu (DS=0.01, 0.1, 1μM;Cu=0.5μM clearly inhibited the growth of AML-colony-forming units (CFUs) for both CD34+CD38-LSC enriched subpopulations (AML-CFUs decreased from 34.2% to 0% in KG1a cells), but was relatively sparing to normal hematopoietic progenitors. Further more, using flow cytometric analysis, western blot and RT-PCR, we identified that the change in redox status and redox-dependent signaling events play a crucial role in DS/Cu-induced apoptosis. We showed that DS/Cu(DS= 0.625,1.25,2.5,5μM, Cu=1μM) increased reactive oxygen species (ROS) and activated its downstream apoptosis-related SAPK/JNK pathway in association with blockade translocation of Nrf2 and expression of Nrf2-regulated genes in CD34+CD38−KG1a cells. Notably, blockade of ROS by glutathione precursor N-acetylcysteine (NAC)(10mM) strongly diminished DS/Cu mediated lethality and restored Nrf2 nuclear translocation and blocked JNK activation. Additionally, consistent with the ROS accumulation, we also seen that translocation of RelA/p65 and the expression of NF-κb-related gene, associated with abnormal apoptotic response of LSCs, were significantly inhibited by DS/Cu. Conclusion Taken together, we concluded that DS/Cu might selectively eradicate LSCs by induction of oxidatibe stress and blockade the NF-κb pathway and offers a potential therapeutic option in AML. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 4869 Disulfiram (DS), an antialcoholism drug, demonstrates strong antitumor activity in a copper (Cu)-dependent manner. Our previous study showed that it is highly cytotoxic in doxorubicin resistant leukemia cells and enhances cytotoxicity of doxorubicin. DS/Cu induces reactive oxidative stress (ROS) which activates stress related signaling pathway (c-Jun-amino-terminal kinase, JNK). Cancer cells possess higher ROS activity and some antiapoptotic factors. Therefore cancer cells may be effectively targeted by simultaneous inducing ROS and inhibiting antiapoptotic factors. Our study investigated the cytotoxicity of DS/Cu complex in acute lymphoblastic leukemia and Burkitt's lymphoma cell lines. MTT assay showed that at a low concentration (1μM) of Cu2+, DS induces cytotoxicity to Molt4 and Raji cells with IC50s of 0.435±0.109μM and 0.085±0.015μM respectively. The morphology and Annexin-V/PI flow cytometric analysis indicated that DSF/Cu induced apoptosis of Molt4 and Raji cells. The apoptotic proportion of Molt4 cells increased from 17.75% to 79.5% when exposed to increasing concentrations of DS (0.125, 0.25, 0.5, 1μM) for 24h. The DS/Cu induced apoptosis is also time-dependent. The apoptotic proportion of Raji cells increased from 18.89±5.86% to 81.03±7.91% when exposed to DS (3.3μM) and Cu (1μM) for 6, 12 and 24h. Nrf2 is a key antioxidant factor. Western blot indicated that Nrf2 nuclear translocation was changed in a time-dependent manner after cells being treated by DS/Cu. Nrf2 expression was increased when Raji cells were treated for less than 12h and decreased after 18h or 24h treatment (Figure 1). Inhibition of Nrf2 could also be seen in Molt4 cells after 24h treatment. QT-PCR showed that DS/Cu down-regulated Nrf2 gene expression in a concentration dependent manner. ROS levels are closely related to Nrf2. Flow cytometric analysis showed that DS/Cu induced ROS generation. Western blot manifested that DS/Cu complex induced phosphorylation of JNK expression and inhibited P65 activity (Figure 2). N-acetyl-L-cysteine (NAC), an antioxidant, can partially attenuate DS/Cu complex-induced apoptosis, restore Nrf2 nuclear translocation, reactivate P65 activity and block JNK activation (Figure 3). In conclusion, our study showed that DS/Cu induces apoptosis in vitro and shows anticancer activity in vivo to lymphoid malignancy cell lines. We also demonstrated that ROS played a key role in DS/Cu- induced apoptosis. ROS can partially inhibit P65 activity and activate JNK while having bi phase regulation of Nrf2 expression. The initially increased Nrf2 expression decreases after 18h and 24h treatment. Therefore the DS/Cu induced ROS may be higher than that antioxidant factors could protect and thus the Nrf2-mediated cellular survival mechanism was disabled through down regulation of Nrf2 to allow initiation of death process. Figure 1. Bi phase regulation (right) and decrease (left) of Nrf2 expression in Molt4 (left) and Raji (right) cells Figure 1. Bi phase regulation (right) and decrease (left) of Nrf2 expression in Molt4 (left) and Raji (right) cells Figure 2. Inhibition of P65 activity and activation of JNK by DS/Cu in Molt4 (left) and Raji (right) cells Figure 2. Inhibition of P65 activity and activation of JNK by DS/Cu in Molt4 (left) and Raji (right) cells Figure 3. Partially restoration of Nrf2 nucelar translocation, block of inhibition of P65 activity and activation of JNK in Molt4 (A) and Raji (B) cells Figure 3. Partially restoration of Nrf2 nucelar translocation, block of inhibition of P65 activity and activation of JNK in Molt4 (A) and Raji (B) cells Disclosures: No relevant conflicts of interest to declare.