Songfu Jiang

Musashi-2 Silencing Exerts Potent Activity against Acute Myeloid Leukemia and Enhances Chemosensitivity to Daunorubicin.

RNA-binding protein Musashi-2 (Msi2) is known to play a critical role in leukemogenesis and contributes to poor clinical prognosis in acute myeloid leukemia (AML). However, the effect of Msi2 silencing on treatment for AML still remains poorly understood. In this study, we used lentivirus-mediated RNA interference targeting Msi2 to investigate the resulting changes in cellular processes and the underlying mechanisms in AML cell lines as well as primary AML cells isolated from AML patients. We found that Msi2 was highly expressed in AML cells, and its depletion inhibited Ki-67 expression and resulted in decreased in vitro and in vivo proliferation. Msi2 silencing induced cell cycle arrest in G0/G1 phase, with decreased Cyclin D1 and increased p21 expression. Msi2 silencing induced apoptosis through down-regulation of Bcl-2 expression and up-regulation of Bax expression. Suppression of Akt, Erk1/2 and p38 phosphorylation also contributed to apoptosis mediated by Msi2 silencing. Finally, Msi2 silencing in AML cells also enhanced their chemosensitivity to daunorubicin. Conclusively, our data suggest that Msi2 is a promising target for gene therapy to optimize conventional chemotherapeutics in AML treatment.

Maintenance therapy with all-trans retinoic acid and arsenic trioxide improves relapse-free survival in adults with low- to intermediate-risk acute promyelocytic leukemia who have achieved complete remission after consolidation therapy.

Background Currently, the optimal maintenance therapy for patients with acute promyelocytic leukemia (APL) who have achieved complete remission (CR) after completing consolidation chemotherapy remains controversial. The comparative effectiveness of the all-trans retinoic acid (ATRA) plus arsenic trioxide (As2O3) maintenance strategy with classic ATRA plus chemotherapy has not been evaluated. In this study, we compared the efficacy and toxicity of maintenance therapy with ATRA plus As2O3 and classic ATRA plus chemotherapy in low- to intermediate-risk APL patients reaching the first CR after induction and consolidation therapy. Methods A retrospective review of 58 adult patients diagnosed with APL was conducted. After receiving consolidation therapy and achieving CR, 30 patients were administered maintenance therapy with an ATRA plus As2O3 regimen (ATRA+As2O3 group), whereas 28 patients were administered 3-monthly cycles of an ATRA plus chemotherapy regimen (ATRA+chemotherapy group). Results Grade 3–4 neutropenia was significantly more frequent in the ATRA+chemotherapy group (N=9, 32.1%) than in the ATRA+As2O3 group (N=0) (P=0.001). At a median follow-up of 49.1 months (range: 9.7–97.4 months) from the completion of consolidation, no relapses were observed in the ATRA+As2O3 group, whereas seven relapses occurred in the ATRA+chemotherapy group. The risk of relapse in the patients administered ATRA+As2O3 maintenance was significantly lower than that in those administered ATRA+chemotherapy maintenance (P=0.004). Based on log-rank analysis, only maintenance therapy with ATRA and As2O3 was associated with a significantly higher relapse-free survival (P=0.0159). Conclusion Maintenance therapy with ATRA and As2O3 was beneficial in low- to intermediate-risk APL patients who were effectively treated to achieve CR. Further clinical trials with reliable designs are needed to confirm these observations.

Quercetin suppresses the proliferation of multiple myeloma cells by down-regulating IQ motif-containing GTPase activating protein 1 expression and extracellular signal-regulated kinase activation

Abstract The flavonoid quercetin has shown anti-tumor effects against a variety of solid tumors. However, its effects on multiple myeloma (MM) remain unclear. In this study we examined the proliferation of human myeloma cell lines U266, KM3 and RPMI8226 and MM derived cells from four patients with MM after quercetin treatment, and detected the expression of IQ motif-containing GTPase activating protein 1 (IQGAP1), a scaffold protein involved in mitogen-activated protein kinase (MAPK) signaling, by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. We found that quercetin inhibited the proliferation of MM cells in a dose- and time-dependent manner, accompanied by reduced IQGAP1 expression at mRNA and protein levels, and reduced extracellular signal-regulated kinase 1/2 (ERK1/2) activation. Furthermore, we found that quercetin inhibited the interaction between IQGAP1 and ERK1/2 in RPMI8226 cells. In summary, our results suggest that quercetin suppresses the proliferation of MM cells by down-regulating IQGAP1 expression and ERK activation, and has potential as a novel agent to target oncogenic kinase cascades for MM therapy.

IQGAP1 plays an important role in the cell proliferation of multiple myeloma via the MAP kinase (ERK) pathway.

The present study was designed to explore the role of IQ motif-containing GTPase activating protein 1 (IQGAP1) in the cell proliferation of multiple myeloma (MM) via the MAP kinase (ERK) pathway. Reverse transcription‑polymerase chain reaction (RT-PCR) and western blot analysis were carried out to evaluate the expression of IQGAP1 in RPMI8226, U266 and KM3 cell lines and in primary MM cells from 4 MM patients. shRNA-expressing plasmids were used in RPMI8226 cells to knock down IQGAP1 and an MTT assay was used to examine the proliferative activity of the RPMI8226-shIQGAP1 (clone 1), RPMI8226-shRNA negative and untransfected RPMI8226 cells in subgroups stimulated with VEGF/IL-6 or without. Western blot analyses were then performed to examine the protein levels of p-ERK1/2, ERK1/2, AKT, p-AKT, STAT3, p-STAT3 in the RPMI8226-shIQGAP1 (clone 1), RPMI8226-shRNA negative and untransfected RPMI8226 cells. Co-immunoprecipitation was used to verify the interaction between the IQGAP1 scaffold and the MAP ERK kinase. We found that IQGAP1 was overexpressed in the human myeloma cell lines and in the patient MM cells. The proliferation rate in the RPMI8226 cells was decreased when IQGAP1 was knocked down with shRNA. IQGAP1 was found to affect RPMI8226 cell proliferation by regulation of the MAP kinase (ERK1/2) pathway; IQGAP1 scaffold-MAP kinase (ERK) interaction was noted in the human myeloma RPMI8226 cell lines. In conclusion, IQGAP1 plays an important role in the cell proliferation of MM via the MAP kinase (ERK) pathway.

Benzene metabolite hydroquinone induces apoptosis of bone marrow mononuclear cells through inhibition of β-catenin signaling

The Akt/glycogen synthase kinase-3β (GSK-3β)/β-catenin signaling pathway has been shown to play an important role in hematopoiesis, and hematopoietic cells are sensitive targets for benzene-induced hematotoxicity. We therefore hypothesized that dysregulation of the Akt/GSK-3β/β-catenin signaling was associated with benzene-induced hematotoxicity. Here, we showed that hydroquinone (HQ), a major metabolite of benzene in humans, significantly inhibited cell viability and colony formation while inducing apoptosis of human bone marrow mononuclear cells in vitro. Interestingly, we found that HQ inhibited the Akt affected β-catenin signaling by activation of GSK-3β, resulting in downregulation of β-catenin and its targets Cyclin D1 and Survivin. HQ blocked nuclear translocation of β-catenin and lymphoid enhancer-binding factor 1 (LEF-1), and importantly, HQ also reduced the interaction of β-catenin and LEF-1 in the nucleus. As expected, blockage of GSK-3β activity with a GSK-3β inhibitor lithium chloride (LiCl) or activation of Akt signaling with an Akt agonist insulin-like growth factor-1 (IGF-1) could inhibit HQ-induced activation of GSK-3β as well as hematotoxicity. Taken together, our results suggest that HQ-induced hematotoxicity in bone marrow mononuclear cells is associated with dysregulation of Akt/GSK-3β/β-catenin signaling due to the dissociation of β-catenin/LEF-1 complex, and LiCl and IGF-1 may be two potential agents to ameliorate HQ-induced hematotoxicity.

Prognostic significance of the red blood cell distribution width in diffuse large B-cell lymphoma patients

This study examined the prognostic value of the baseline red blood cell distribution width (RDW) in diffuse large B cell lymphoma (DLBCL) patients. The associations between RDW and clinical characteristics were assessed in 161 DLBCL patients from 2005 to 2016. The log-rank test, univariate analysis, and Cox regression analysis were used to evaluate the relationship between RDW and survival. A RDW of 14.1% was considered to be the optimal cut-off value for predicting prognosis. A high RDW was associated with more frequent B symptoms (P=0.001), a higher International Prognostic Index score (P=0.032), more extranodal sites of disease (P=0.035), and significantly lower Eastern Cooperative Oncology Group performance status (P=0.031). The log-rank test demonstrated that patients with a high RDW had a shorter overall survival (OS) (2-year OS rate, 53.6% vs. 83.6%, P<0.001) and progression-free survival (PFS) (2-year PFS rate, 44.7% vs. 81.8%, P<0.001). The multivariate analysis demonstrated that RDW ≥14.1% was an independent predictor of OS (odds ratio [OR] = 0.345, P<0.001) and PFS (OR = 0.393, P=0.001). We demonstrated that a high RDW predicted an unfavorable prognosis in patients with DLBCL.

Effect of absolute monocyte count post-transplant on the outcome of patients with acute myeloid leukemia undergoing myeloablative allogeneic hematopoietic stem cell transplant with busulfan and cyclophosphamide conditioning

Peripheral monocytes have recently been evaluated as a prognostic factor in different types of hematological malignancies. This study assessed the prognostic value of absolute monocyte count (AMC) post-transplant on the clinical outcomes of 59 patients with acute myeloid leukemia (AML) who had undergone myeloablative conditioning (MAC) allogeneic hematopoietic stem cell transplant (allo-HSCT) with busulfan and cyclophosphamide (Bu/Cy). Kaplan-Meier analysis showed that patients with a high AMC (≥ 0.57 × 109/L) on post-transplant day (PTD) 15 had a significantly worse overall survival (OS) compared to patients with a low AMC (< 0.57 × 109/L) on PTD 15 (P = .0049). Univariate Cox proportional hazard analyses revealed that only high AMC on PTD 15 was a poor prognostic factor for OS (P = .008) and post-relapse survival (P = .030). We conclude that AMC ≥ 0.57 × 109/L on PTD 15 is associated with more deaths in patients with AML who have undergone MAC allo-HSCT with Bu/Cy.

Inhibition of autophagy enhances the antitumour activity of tigecycline in multiple myeloma

Accumulating evidence shows that tigecycline, a first‐in‐class glycylcycline, has potential antitumour properties. Here, we found that tigecycline dramatically inhibited the proliferation of multiple myeloma (MM) cell lines RPMI‐8226, NCI‐H929 and U266 in a dose and time‐dependent manner. Meanwhile, tigecycline also potently impaired the colony formation of these three cell lines. Mechanism analysis found that tigecycline led to cell cycle arrest at G0/G1 with down‐regulation of p21, CDK2 and cyclin D1, rather than induced apoptosis, in MM cells. Importantly, we found that tigecycline induced autophagy and an autophagy inhibitor bafilomycin A1 further amplified the tigecycline‐induced cytotoxicity, suggesting that autophagy plays a cytoprotective role in tigecycline‐treated MM cells. Mechanisms modulating autophagy found that tigecycline enhanced the phosphorylation of AMPK, but did not decrease the phosphorylation of Akt, to inhibit the phosphorylation of mTOR and its two downstream effectors p70S6K1 and 4E‐BP1. Tigecycline effectively inhibited tumour growth in the xenograft tumour model of RPMI‐8226 cells. Autophagy also occurred in tigecycline‐treated tumour xenograft, and autophagy inhibitor chloroquine and tigecycline had a synergistic effect against MM cells in vivo. Thus, our results suggest that tigecycline may be a promising candidate in the treatment of MM.

Mean platelet volume predicts prognosis in patients with diffuse large B-cell lymphoma

To determine the prognostic value of baseline mean platelet volume (MPV) in diffuse large B‐cell lymphoma (DLBCL) patients. We retrospectively analyzed 161 DLBCL patients who received R‐CHOP chemotherapy. The associations between MPV and clinicopathological factors were assessed. A low MPV (MPV ≤ 9.1 fl, cut‐off was calculated by receiver operating characteristics) was not associated with any other clinicopathological factors. Patients with MPV ≤ 9.1 fl experienced a shorter progression‐free survival (PFS) (2‐year PFS rate, 60.6% vs 84.0%, P = 0.003) and overall survival (OS) (2‐year OS rate, 70.4% vs 87.9%, P = 0.030), compared with those with MPV > 9.1 fl. The multivariate analysis demonstrated that MPV ≤ 9.1 fl was an independent prognostic factor of OS (Hazard Ratio [HR] = 0.588, P = 0.045) and PFS (HR = 0.456, P = 0.010). Therefore, we demonstrated that low baseline MPV is an independent prognostic marker of poor outcome in patients with DLBCL.

Acute Myeloid Leukemia Cells Express ICOS Ligand to Promote the Expansion of Regulatory T Cells

CD4+CD25+Foxp3+ regulatory T cells (Tregs) accumulate in bone marrow microenvironment in acute myeloid leukemia (AML). However, little is known about how the tumor environment including tumor cells themselves affects this process. Here we demonstrated that AML cells expressed inducible T-cell costimulator ligand (ICOSL) that can provide costimulation through ICOS for the conversion and expansion of Tregs sustaining high Foxp3 and CD25 expression as well as a suppressive function. TNF-a stimulation up-regulated the expression of ICOSL. Furthermore, both the conversion and expansion of CD4+CD25+Foxp3+ T cells and CD4+ICOS+Foxp3+ T cells were induced by co-culture with AML cells overexpressed ICOSL. CD4+CD25+ICOS+ T cells possessed stronger ability to secrete IL-10 than CD4+CD25+ICOS− T cells. The mechanism by which IL-10 promoted the proliferation of AML cells was dependent on the activation of the Akt, Erk1/2, p38, and Stat3 signaling pathways. Blockade of ICOS signaling using anti-ICOSL antibody impaired the generation of Tregs and retarded the progression of an AML mice model injected with C1498 cells. The expression of ICOSL of patient AML cells and ICOS+ Tregs were found to be predictors for overall survival and disease-free survival in patients with AML, with ICOS+ Treg cell subset being a stronger predictor than total Tregs. These results suggest that ICOSL expression by AML cells may directly drive Treg expansion as a mechanism of immune evasion and ICOS+ Treg cell frequency is a better prognostic predictor in patients with AML.