Bing Xiu

PD-1 expression defines two distinct T-cell sub-populations in follicular lymphoma that differentially impact patient survival

To determine the biological and clinical relevance of programmed death 1 (PD-1) in follicular lymphoma (FL), we characterized PD-1+ T-cell subsets and assessed their biological function as well as potential clinical impact. We found that PD-1 is expressed on intratumoral CD4+ T cells with both bright and dim intensity, representing two different sub-populations of cells. By immunohistochemistry, we found that CD4+PD-1high T cells predominantly reside in the lymph node follicles, while PD-1low T cells are mainly located in an interfollicular pattern. Intratumoral CD4+PD-1high T cells have a TFH cell phenotype, express CXCR5, secrete IL-21 and are BCL-6 positive with no TIM-3 expression. In contrast, CD4+PD-1low T cells have an exhausted phenotype, express TIM-3 and do not express BCL-6 and CXCR5. Functionally, CD4+PD-1high T cells actively supported B-cell growth, while CD4+PD-1low T cells displayed a reduced cytokine production and cell-signal transduction. Clinically, we observed that the numbers of CD4+ or CD8+PD-1low T cells significantly correlate with a reduced overall survival in FL patients (P=0.007 and 0.04 respectively; n=32). In contrast, the number of CD4+PD-1high T cells was not associated with patient outcome. Taken together, these results indicated that PD-1 expression defines two sub-populations with distinct functions that differentially impact patient outcome in FL.

TGF-Β upregulates CD70 expression and induces exhaustion of effector memory T cells in B-cell non-Hodgkin's lymphoma

Transforming growth factor beta (TGF-β) has an important role in mediating T-cell suppression in B-cell non-Hodgkin lymphoma (NHL). However, the underlying mechanism responsible for TGF-β-mediated inhibition of effector memory T (Tm) cells is largely unknown. As reported here, we show that exhaustion is a major mechanism by which TGF-β inhibits Tm cells, and TGF-β mediated exhaustion is associated with upregulation of CD70. We found that TGF-β upregulates CD70 expression on effector Tm cells while it preferentially induces Foxp3 expression in naive T cells. CD70 induction by TGF-β is Smad3-dependent and involves IL-2/Stat5 signaling. CD70+ T cells account for TGF-β-induced exhaustion of effector Tm cells. Both TGF-β-induced and preexisting intratumoral CD70+ effector Tm cells from B-cell NHL have an exhausted phenotype and express higher levels of PD-1 and TIM-3 compared with CD70− T cells. Signaling transduction, proliferation and cytokine production are profoundly decreased in these cells, and they are highly susceptible to apoptosis. Clinically, intratumoral CD70-expressing T cells are prevalent in follicular B-cell lymphoma (FL) biopsy specimens, and increased numbers of intratumoral CD70+ T cells correlate with an inferior patient outcome. These findings confirm TGF-β-mediated effector Tm cell exhaustion as an important mechanism of immune suppression in B-cell NHL.

Pattern of CD14+ follicular dendritic cells and PD1+ T cells independently predicts time to transformation in follicular lymphoma

Purpose: Transformation of follicular lymphoma is a critical event associated with a poor prognosis. The role of the tumor microenvironment in previous transformation studies has yielded conflicting results. Experimental Design: To define cell subtypes associated with transformation, we examined tissue specimens at diagnosis from patients with follicular lymphoma that later transformed and, using immunohistochemistry (IHC), stained for CD68, CD11c, CD21, CXCL13, FOXP3, PD1, and CD14. Cell content and the pattern of expression were evaluated. Those identified as significantly associated with time to transformation (TTT) and overall survival (OS) were further characterized by flow cytometry and multicolor IHC. Results: Of note, 58 patients were analyzed with median TTT of 4.7 years. The pattern of PD1+ and CD14+ cells rather than the quantity of cells was predictive of clinical outcomes. On multivariate analysis, including the follicular lymphoma international prognostic index score, CD14+ cells localized in the follicle were associated with a shorter TTT (HR, 3.0; P = 0.004). PD1+ cells with diffuse staining were associated with a shorter TTT (HR, 1.9; P = 0.045) and inferior OS (HR, 2.5; P = 0.012). Multicolor IHC and flow cytometry identified CD14+ cells as follicular dendritic cells (FDC), whereas PD1+ cells represented two separate populations, TFH and exhausted T cells. Conclusion: These results identify the presence of PD1+ T cells and CD14+ FDC as independent predictors of transformation in follicular lymphoma. Clin Cancer Res; 20(11); 2862–72. ©2014 AACR.

Proteomic Analysis Identified DJ-1 as a Cisplatin Resistant Marker in Non-Small Cell Lung Cancer

The aim of study is to identify cisplatin-resistance associated biomarkers for non-small cell lung cancers (NSCLC). We use two-dimensional electrophoresis (2-DE) combined with MALDI-TOF mass spectrometry to compare the proteome between lung cancer cell line A549 and its cisplatin-resistant subline A549/DDP. Nine cisplatin resistance-related proteins were identified, and DJ-1, one of the differently expressed proteins, was selected for further validation and evaluation. Immunohistochemical results demonstrated that high expression level of DJ-1 was associated with cisplatin resistance and a predictor for poor prognosis in 67 locally advanced NSCLC patients. Furthermore, in vitro results showed that silencing DJ-1 increased the proliferation inhibitory effect of cisplatin to A549/DDP cells. In conclusion, DJ-1 might play an important role in the resistibility to cisplatin, and it could also act as a novel candidate biomarker for predicting the response of NSCLC patients to cisplatin-based chemotherapy.

Soluble and Membrane-Bound TGF-β-Mediated Regulation of Intratumoral T Cell Differentiation and Function in B-Cell Non-Hodgkin Lymphoma

While the effect of TGF-β on malignant B cells in non-Hodgkin lymphoma (NHL) has been previously evaluated, studies to specifically define the role of TGF-β in tumor immunity in B-cell NHL are limited. We found that soluble TGF-β, secreted by both lymphoma cells and intratumoral T cells, is present in the serum of patients with B-cell NHL. Soluble TGF-β promoted regulatory T (Treg) cells by enhancing expression of Foxp3 in CD4+ T cells and suppressed effector helper T (TH) cells by inhibiting expression of IFN-γ and IL-17. Blockade of the IL-2 signaling pathway diminished the effect of soluble TGF-β on T cell differentiation. Furthermore, we found that membrane-bound TGF-β is expressed specifically on the surface of malignant B cells in B-cell NHL. TGF-β was able to bind to the surface of lymphoma B cells through an interaction with heparan sulfate (HS) but not through the TGF-β receptor. We showed that pretreatment of lymphoma B cells with TGF-β significantly inhibits the proliferation and cytokine production of intratumoral T cells. Taken together, these results suggest that tumor-associated soluble and membrane-bound TGF-β are involved in the regulation of intratumoral T cell differentiation and function in B-cell NHL.

Down-regulation of SENP1 expression increases apoptosis of Burkitt lymphoma cells.

OBJECTIVE To investigate the effect of down-regulation of Sentrin/SUMO-specific protease 1 (SENP1) expression on the apoptosis of human Burkitt lymphoma cells (Daudi cells) and potential mechanisms. METHODS Short hairpin RNA (shRNA) targeting SENP1 was designed and synthesized and then cloned into a lentiviral vector. A lentiviral packaging plasmid was used to transfect Daudi cells (sh-SENP1-Daudi group). Daudi cells without transfection (Daudi group) and Daudi cells transfected with blank plasmid (sh-NC-Daudi group) served as control groups. Flow cytometry was performed to screen GFP positive cells and semiquantitative PCR and Western blot assays were employed to detect the inference efficiency. The morphology of cells was observed under a microscope before and after transfection. Fluorescence quantitative PCR and Western blot assays were conducted to measure the mRNA and protein expression of apoptosis related molecules (caspase-3, 8 and 9). After treatment with COCl2 for 24 h, the mRNA and protein expression of hypoxia inducible factor -1α (HIF-1α) was determined. RESULTS Sequencing showed the expression vectors of shRNA targeting SENP1 to be successfully constructed. Following screening of GFP positive cells by FCM, semiqualitative PCR showed the interference efficiency was 79.2±0.026%. At 48 h after transfection, the Daudi cells became shrunken, had irregular edges and presented apoptotic bodies. Western blot assay revealed increase in expression of caspase-3, 8 and 9 with prolongation of transfection (P<0.05). Following hypoxia treatment, mRNA expression of HIF-1α remained unchanged in three groups (P>0.05) but the protein expression of HIF-1α markedly increased (P<0.05). However, in the sh-SENP1-Daudi group, the protein expression of HIF-1α remained unchanged. CONCLUSION SENP1-shRNA can efficiently inhibit SENP1 expression in Daudi cells. SENP1 inhibition may promote cell apoptosis. These findings suggest that SENP1 may serve as an important target in the gene therapy of Burkitts lymphoma.

Nanocomposite-siRNA approach for down-regulation of VEGF and its receptor in myeloid leukemia cells

BACKGROUND Efficient modulation of aberrant vascular endothelial growth factor (VEGF) and its receptor-1 (Flt-1) expressions have become a potential therapeutic strategy for hematologic malignancies including myeloid leukemia. In this study, we explored the safety and efficacy of chitosan nanoparticle siRNA-VEGF and Flt-1 in leukemic U973 cells. METHODS Cell transfection efficiencies were analyzed by fluorescence microscope, quantitative Real Time PCR; cell growth inhibitory rates were analyzed by CCK-8 assays and flow cytometry. RESULTS siRNA-coated chitosan nanosphere transfection led to 65%, Lipofectamine 2000 to 50% and adenovirus to 90% transfection efficiencies. Three days after transfection of U973 cells, the siRNA induced gene silencing rates of VEGF and Flt-1 were 68% and 65% in the adenovirus, 45% and 43% in the chitosan nanoparticle group. The cell growth inhibitory rates were 34.73% for VEGF and 27.61% for Flt-1 silencing in the adenovirus and 27.04% for VEGF and 21.49% for Flt-1 silencing in the chitosan nanoparticle group. CONCLUSION Chitosan nanoparticle siRNA technology can effectively inhibit the expression of VEGF and its receptor in leukemic cells, which led to suppression of their proliferation. Though less efficient than adenoviruses, their non-viral properties suggest that chitosan nanoparticle siRNA complex gene silencing is suitable for further trials.

Genetic inhibition of vascular endothelial growth factor receptor-1 significantly inhibits the migration and proliferation of leukemia cells and increases their sensitivity to chemotherapy

Little is known about the role of vascular endothelial growth factor (VEGF) receptor-1 (VEGFR-1) in acute leukemia. In this study, using real-time PCR and ELISA, we found that VEGF and VEGFR-1 are highly expressed in U937 leukemia cells and primary leukemia cells (M4/M5 subtypes), which are associated with an increased migration rate and extramedullary disease. In order to elucidate the role of VEGFR-1 in acute leukemia, we used a lentivirus-mediated shRNA expression system to specifically inhibit VEGFR-1 expression in the U937 cell line. In addition, a series of in vitro experiments were conducted, including cell proliferation and migration assays and drug treatments. Our results showed that shRNA reduced the proliferation and migration of U937 cells. RNA interference targeting VEGFR-1 in combination with bevacizumab did not exert synergistic antitumor effects. However, shRNA enhanced the sensitivity of the U937 cells to cytarabine by decreasing the IC50 of cytarabine, reducing the number of cells in the S phase and suppressing the expression of the survivin gene. Taken together, these results suggest that VEGFR-1 interference may serve as a novel antitumor therapeutic strategy for the treatment of leukemia.

N-Propionyl polysialic acid precursor enhances the susceptibility of multiple myeloma to antitumor effect of anti-NprPSA monoclonal antibody.

Aim:To study the antitumor effect of anti-NprPSA monoclonal antibody (mAb) in combination with ManNPr, a precursor of N-propionyl PSA, in multiple myeloma (MM), and to explore the mechanisms of the action.Methods:Human multiple myeloma cell line RPMI-8226 was tested. The cells were pre-treated with ManNPr (1, 2, and 4 mg/mL), and then incubated with anti-NprPSA mAb (1 mg/mL). Cell apoptosis in vitro was detected using MTT assay and flow cytometry. BALB/c nude mice were inoculated sc with RPC5.4 cells. On 5 d after the injection, the mice were administered sc with anti-NprPSA mAb (200 μg/d) and ManNPr (5 mg/d) for 8 d. The tumor size and body weight were monitored twice per week. TUNEL assay was used for detecting apoptosis in vivo. The apoptotic pathway involved was examined using Western blot analysis and caspase inhibitor.Results:Treatment of RPMI-8226 cells with anti-NprPSA mAb alone failed to inhibit cell growth in vitro. In RPMI-8226 cells pretreated with ManNPr, however, the mAb significantly inhibited the cell proliferation, decreased the viability, and induced apoptosis, which was associated with cleavage of caspase-3, caspase-8, caspase-9, and poly(ADP-ribose) polymerase. In the mouse xenograft model, treatment with the mAb in combination with ManNPr significantly inhibited the tumor growth, and induced significant apoptosis as compared to treatment with the mAb alone. Moreover, apoptosis induced by the mAb in vivo resulted from the activation of the caspases and poly(ADP-ribose) polymerase.Conclusion:The anti-NprPSA mAb in combination with ManNPr is an effective treatment for in vitro and in vivo induction of apoptosis in multiple myeloma.

Efficacy and safety of combined immunosuppressive therapy plus umbilical cord blood infusion in severe aplastic anemia patients: A cohort study

The present study aimed to evaluate the efficacy and safety of combined immunosuppressive therapy (IST) plus umbilical cord blood infusion (UCBI) in severe aplastic anemia (SAA) patients. A total of 68 patients with SAA were enrolled in the current prospective cohort study and divided into the IST (n=35; positive control) and IST+UCBI (n=33; experimental) groups according to the treatment conditions. Patients in the IST group were treated with rabbit antithymocyte globulin (r-ATG) at a dose of 2.5 mg/kg through intravenous infusion once a day for five days. This was combined with oral cyclosporine A (CsA) at a dose of 3–5 mg/kg twice a day for 2 years. Patients in the IST+UBCI group were treated with r-ATG and CsA at the same doses and frequencies as the IST group plus one UCBI 1 day after the final treatment with r-ATG. At 6 months post treatment, the complete response and overall response rate (ORR) of the IST+UCBI group were markedly higher compared with those in the IST group. Furthermore, patients in the IST+UCBI group achieved absolute neutrophil count (ANC) and platelet count responses more rapidly as compared with the IST group. However, no difference in the hemoglobin (Hb) response was identified between the two groups. In addition, SAA patients achieved responses in the ANC and platelet count more rapidly in comparison with very severe aplastic anemia (VSAA) patients, while the number of days to Hb responses were similar in the SAA and VSAA patients. Multivariate logistic regression analysis also revealed that IST+UCBI treatment was an independent predicting factor for patients achieving complete response or partial response, whereas VSAA was an independent predictor of a worse ORR. Platelet and reticulocyte were also independent predicting factors. Finally, the survival of patients was similar between the groups, and no difference in the safety of the treatment was observed. In conclusion, combined IST plus UCBI treatment may be applied as an effective and safe therapy for SAA patients.