E35 ablates acute leukemia stem and progenitor cells in vitro and in vivo.

Leukemia stem cells (LSCs) have critical functions in acute leukemia (AL) pathogenesis, participating in its initiation and relapse. Thus, identifying new molecules to eradicate LSCs represents a high priority for AL management. This work identified E35, a novel Emodin derivative, which strongly inhibited growth and enhanced apoptosis of AL stem cell lines, and primary stem and progenitor cells from AL cases, while sparing normal hematopoietic cells. Furthermore, functional assays in cultured cells and animals suggested that E35 preferentially ablated primitive leukemia cell populations without impairing their normal counterparts. Moreover, molecular studies showed that E35 remarkably downregulated drug-resistant gene and dramatically inhibited the Akt/mammalian target of rapamycin signaling pathway. Notably, the in vivo anti-LSC activity of E35 was further confirmed in murine xenotransplantation models. Collectively, these findings indicate E35 constitutes a novel therapeutic candidate for AL, potentially targeting leukemia stem and progenitor cells.

Effect of nucleolin on adriamycin resistance via the regulation of B-cell lymphoma 2 expression in Burkitt's lymphoma cells.

Nucleolin (NCL, C23) is an important nucleocytoplasmic multifunctional protein. Due to its multifaceted profile and high expression in cancer, NCL is considered to be a marker of drug resistance associated with chemotherapy. However, the biochemical mechanisms in which NCL suppresses drug sensitivity in several cancers have yet to be fully elucidated. This study aims to explore the effect of NCL on drug sensitivity and its potential mechanism in CA46 Burkitt's lymphoma (BL) cells. CA46 BL cells were transfected with lentiviruses carrying the NCL gene (CA46-NCL-overexpression, CA46-NCL-OE), or shRNA sequences that target the endogenous NCL gene (CA46-NCL-knockdown, CA46-NCL-KD). Adriamycin (ADM) IC50 levels for CA46-NCL-overexpressed (OE), CA46-NCL-OE control (OEC), CA46-NCL-knockdown (KD), and CA46-NCL-KD control (KDC) cells were 0.68 ± 0.06 µg/ml, 0.68 ± 0.06 µg/ml, 0.68 ± 0.06 µg/ml, and 0.30 ± 0.04 µg/ml, respectively. Apoptosis rates were significantly increased following NCL KD, whereas the opposite effect was noted in OE cells. A significant reduction of B-cell lymphoma 2 (Bcl-2) mRNA and protein levels in KD cells was observed, while OE cells displayed the opposite effect. The stability of Bcl-2 mRNA was influenced by NCL levels, the half-life of which was extended after NCL-OE, whereas it was reduced in KD cells. Finally, results of RNA-immunoprecipitation assays indicated that NCL could bind to Bcl-2 mRNA in CA46 cells. Taken together, these results suggested that NCL could mediate Bcl-2 expression and stability, and thus enhance ADM resistance in CA46 BL cells.

Emodin and Its Combination with Cytarabine Induce Apoptosis in Resistant Acute Myeloid Leukemia Cells in Vitro and in Vivo.

BACKGROUND/AIMS: Acute myeloid leukemia (AML) remains a hematologic malignancy with poor survival and a high risk of relapse, which is mainly caused by the emergence of multidrug resistance (MDR). The identification of novel agents to improve therapeutic strategies becomes important priority for AML treatment. It has been shown that emodin has therapeutic effects on many kinds of human malignant tumors. In this study, we investigated the anti-leukemia effects of emodin alone or in combination with cytarabine (Ara-C) on multidrug-resistant AML HL-60/ADR cells and in a mouse xenograft model of human highly tumorigenic AML HL-60/H3 cells. The underlying mechanism was also addressed. METHODS: Cell viability after treatment was measured by MTT assay. The DNA fragmentation assay, Annexin V-PE/7-AAD, AO/EB staining, and electron microscopy were introduced to assess the apoptotic induction effects. Changes in protein expression in the Akt and ERK signaling pathways were determined by western blotting. In vivo antileukemia effects on HL-60/H3 xenograft model and overall mouse survival outcomes were further analyzed in this study. RESULTS: Emodin dose-dependently induced growth inhibition and apoptotic effects in resistant HL-60/ADR cells in vitro as well as in the HL-60/H3 xenograft models in vivo. Moreover, emodin significantly enhanced chemosensitivity of AML cells to Ara-C, inhibited leukemic cell growth, and improved survival in the mouse xenograft model of AML. Dual targeting of Akt and ERK signaling pathways might contribute to the anti-leukemia effects on AML cells in vitro and in vivo. CONCLUSION: Emodin and its combination with Ara-C may be considered a promising therapeutic approach in AML and worthy of further investigation.

Association of Platelet Desialylation and Circulating Follicular Helper T Cells in Patients With Thrombocytopenia.

Thrombocytopenia is a multifactorial condition that frequently involves concomitant defects in platelet production and clearance. The physiopathology of low platelet count in thrombocytopenia remains unclear. Sialylation on platelet membrane glycoprotein and follicular helper T cells (TFHs) are thought to be the novel platelet clearance pathways. The aim of this study was to clarify the roles of platelet desialylation and circulating TFHs in patients with immune thrombocytopenia (ITP) and non-ITP thrombocytopenia. We enrolled 190 patients with ITP and 94 patients with non-ITP related thrombocytopenia including case of aplastic anemia (AA) and myelodysplastic syndromes (MDS). One hundred and ten healthy volunteers were included as controls. We found significantly increased desialylated platelets in patients with ITP or thrombocytopenia in the context of AA and MDS. Platelet desialylation was negatively correlated with platelet count. Meanwhile, the circulating TFH levels in patients with thrombocytopenia were significantly higher than those of normal controls, and were positively correlated with desialylated platelet levels. Moreover, TFHs-related chemokine CXCL13 and apoptotic platelet levels were abnormally high in ITP patients. The upregulation of pro-apoptotic proteins and the activation of the MAPK/mTOR pathway were observed in the same cohort. These findings suggested that platelet desialylation and circulating TFHs may become the potential biomarkers for evaluating the disease process associated with thrombocytopenia in patients with ITP and non-ITP.

Doxorubicin/Nucleophosmin Binding Protein-Conjugated Nanoparticle Enhances Anti-leukemia Activity in Acute Lymphoblastic Leukemia Cells in vitro and in vivo.

Acute lymphoblastic leukemia (ALL) is an aggressive malignancy. Adults with ALL have more than 50% relapse rates. We have previously validated that overexpression of nucleophosmin (NPM) is involved in the multidrug resistance (MDR) development during ALL; and a synthetically engineered recombinant NPM binding protein (NPMBP) has been developed in our group; NPMBP and doxorubicin (DOX) can be conjugated in a nanoparticle-based drug delivery system named DOX-PMs-NPMBP to counteract MDR during ALL. Here, we evaluated the antileukemia potential of DOX-PMs-NPMBP in resistant ALL cells. This study demonstrates that DOX-PMs-NPMBP significantly enhances chemosensitivity to DOX in ALL cells. Despite at variable concentrations, both resistant and primary ALL cells from relapsed patients were sensitive to DOX-PMs-NPMBP. In detail, the half maximal inhibitory concentration (IC50) values of DOX-PMs-NPMBP were between 1.6- and 7.0-fold lower than those of DOX in cell lines and primary ALL cells, respectively; and apoptotic cells ratio was over 2-fold higher in DOX-PMs-NPMBP than DOX. Mechanistically, p53-driven apoptosis induction and cell cycle arrest played essential role in DOX-PMs-NPMBP-induced anti-leukemia effects. Moreover, DOX-PMs-NPMBP significantly inhibited tumor growth and prolonged mouse survival of ALL xenograft models; and no systemic toxicity occurrence was observed after treatment during follow-up. In conclusion, these data indicate that DOX-PMs-NPMBP may significantly exert growth inhibition and apoptosis induction, and markedly improve DOX antileukemia activity in resistant ALL cells. This novel drug delivery system may be valuable to develop as a new therapeutic strategy against multidrug resistant ALL.

Integrated bioinformatics analysis of the crucial candidate genes and pathways associated with glucocorticoid resistance in acute lymphoblastic leukemia.

Glucocorticoids (GC) are the foundation of the chemotherapy regimen in acute lymphoblastic leukemia (ALL). However, resistance to GC is observed more frequently than resistance to other chemotherapy agents in patients with ALL relapse. Moreover, the mechanism underlying the development of GC resistance in ALL has not yet been fully uncovered. In this study, we used bioinformatic analysis methods to integrate the candidate genes and pathways participating in GC resistance in ALL and subsequently verified the bioinformatics findings with in vitro cell experiments. Ninety-nine significant common differentially expressed genes (DEGs) associated with GC resistance were determined by integrating two gene profile datasets, including GC-sensitive and -resistant samples. Using Kyoto Encyclopedia of Genes and Genomes (KEGG) and REACTOME pathways analysis, the signaling pathways in which DEGs were significantly enriched were clustered. The GC resistance-related biologically functional interactions were visualized as DEG-associated Protein-Protein Interaction (PPI) network complexes, with 98 nodes and 127 edges. MYC, a node which displayed the highest connectivity in all edges, was highlighted as the core gene in the PPI network. Increased C-MYC expression was observed in adriamycin-resistant BALL-1/ADR cells, which we demonstrated was also resistant to dexamethasone. These results outlined a panorama in which the solitary and scattered experimental results were integrated and expanded. The potential promising target of the candidate pathways and genes involved in GC resistance of ALL was concomitantly revealed.

[Inhibitory Effect of NPM Gene Knockdown on Proliferation of Chronic Myeloid Leukemia Cell Line K562 and Its Mechanism].

OBJECTIVE: To investigate the role of nucleophosmin (NPM) in the proliferation of chronic myeloid leukemia cells (K562 cells) and its mechanism by RNAi technology. METHODS: shRNA was used to inhibit the expression of NPM. The expression of NPM gene was detected by real-time quantitative PCR. The effect of inhibiting NPM gene on cell proliferation was detected by MTS assay. Change of cell cycle was detected by flow cytometry. Western blot was used to detect the expression of cell cycle-related proteins. RESULTS: The shRNA lentiviral vector targeting at NPM gene was successfully constructed and used to transfect the K562 cells. The results showed that compared with the control groups, suppression of NPM gene expression in K562 cells could inhibit the cell proliferation and decrease the cell colony formation. Moreover, interference of NPM gene could prolong G0/G1 phase and arrest cell cycle, which may be related to the down-regulation of NPM gene expression and activation of p21 protein expression, thereby inhibited the formation of CDK2/ Cyclin E complex. CONCLUSION: Down-regulation of NPM gene expression in K562 cells can induce cell cycle arrest and inhibit cell proliferation.

[Effect of Baicalin Derivative 02-036 on Burkitt Lymphoma Cell Line CA46 and Its Related Mechanisms].

OBJECTIVE: To investigate the effect of baicalin derivative 02-036 on proliferation and apoptosis human Burkitt lymphoma cell line CA46 and its related mechanisms. METHODS: The MTT assay and cell colony formation assay were used to measure the growth inhibition of CA46 cells after 02-036 treatment. The flow cytometry with AnnexinV-FITC/PI double staining was employed to detect the apoptosis induction effect of 02-036 on CA46 cells. Cell cycle distribution of CA46 cells was estimeted by using DNA ploid analysis. Western blot was used to determine the changes of apoptosis-related proteins, including C-MYC, BCL-2, Procaspase-9, Procaspase-3, PARP and Cleaved-PARP. RESULTS: Baicalin derivative 02-036 obviously inhibited the proliferation of CA46 cells, with dose- and time-dependent manner (r=0.963, r=0.992). The averaged IC50 value of CA46 cells was (6.04±0.11) µmol/L after 48-hour treatment. Low concentration of 02-036 could significantly inhibit the colony formation of CA46 cells. Flow cytometry analysis confirmed that 02-036 could effectively induce CA46 cell apoptosis. The apoptosis rate correlated with drug concentrations (r=0.959). Also, DNA ploid analysis showed that the cell cycle of CA46 was arrested in the S phase. The expression levels of BCL-2, Pro-caspase-9, Pro-caspase-3, PARP and C-MYC proteins decreased with a 02-036-dose dependent manner (r values were -0.990, -0.939, -0.971 and -0.967, respectively). In contrast, the expression level of cleaved-PARP increased with the same manner (r=0.920). CONCLUSION: Baicalin derivative 02-036 can effectively inhibit the proliferation and induce apoptosis of CA46 cells, and its related mechanisms may be correlated with the down-regulation of apoptosis-related molecule expression levels, such as BCL-2, Pro-caspase-9, Pro-caspase-3, PARP and C-MYC.

Integration of bioinformatics and experiments to identify TP53 as a potential target in Emodin inhibiting diffuse large B cell lymphoma.

Non-Hodgkin's Lymphoma (NHL) is a group of lymphoid malignancies with unsatisfactory treatment effect in some aggressive subtypes, including diffuse large B cell lymphoma (DLBCL). Emodin is an anthraquinone with potent anti-cancer activities. However, the molecular mechanism of Emodin repressing aggressive NHL remains to be revealed in detail. This study delineated the active mechanism of Emodin action in aggressive NHL by using bioinformatics analysis and in vitro assay. 4 Emodin's primary direct protein targets (DPT) were identified and the DPTs-associated proteins/genes were predicted. Those Emodin-related proteins/genes were subject to enrich Emodin-associated pathways, from which 3 significantly NHL-related signal pathways were refined identified. Advanced integrated analysis exhibited TP53 and PI3K as the significant molecule and pathway by which Emodin may function in NHL. To verify those bioinformatics findings, effects of Emodin and E35, a novel derivative of emodin were investigated on DLBCL cell lines SU-DHL4. Emodin and E35 suppressed proliferation and induced apoptosis of SU-DHL4 cells in a time- and dose-dependent manner. Emodin and E35 declined TP53 protein expression and decreased phosphorylation of PI3K/AKT protein in a dose-dependent manner. All of above showed that combined bioinformatics analysis with experiments offered a novel approach for outlining the mechanisms of Emodin action in DLBCL with convenience and integrity.