Disparity Analysis of Clinicopathologic Hallmarks between Transformed DLBCL and Primary DLBCL.

BACKGROUND: A variety of indolent lymphomas, particularly marginal zone lymphoma (MZL) and follicular lymphoma (FL) can be histologically transformed to diffuse large B-cell lymphoma (DLBCL). Little is known about the disparity of clinicopathologic characteristics between transformed DLBCL (tDLBCL) and primary DLBCL (pDLBCL). METHODS: This retrospective study analyzed the clinicopathological hallmarks of 10 tDLBCL (7 MZL and 3 FL) and 40 pDLBCL from the Affiliated Hospital of Xuzhou Medical University. RESULTS: Patients of tDLBCL had a higher ECOG score, more B-symptoms, and lower serum albumin level than those in pDLBCL (60.0% vs. 7.50%, 40.0% vs. 10.0%, and 90.0% vs. 10.0%, respectively, p < 0.01). Pathologically, tDLBCL had more c-Myc and BCL-2 dual-expression than that in pDLBCL (60.0% vs. 25.0%, p < 0.01). The positive rate of CD5 expression and the proportion of high Ki-67 score in tDLBCL were higher than those in pDLBCL (50.0% vs. 7.5%, 50.0% vs. 32.5%, respectively, p < 0.01). The median overall survival and progression-free survival were 14 months and 11 months in tDLBCL, 35 months and 28 months in pDLBCL (p < 0.05 and p < 0.001). CONCLUSIONS: Our results demonstrate that tDLBCL manifested aggressive clinical course and pathological features of Myc/BCL-2 expression, CD5 expression, and high Ki-67 score.

Clinicopathologic Features and Genomic Signature of De Novo CD5 + Diffuse Large B-Cell Lymphoma : A Multicenter Collaborative Study.

De novo CD5 + diffuse large B-cell lymphoma (DLBCL) has poor survival in the era of immunochemotherapy. Accurate gene-based typing and prognostic stratification can enhance the development of effective individualized treatments. Therefore, we conducted a multicenter retrospective study to evaluate the clinicopathologic characteristics, genomic profiles, and prognostic parameters of 61 patients with CD5 + DLBCL and 60 patients with CD5 - DLBCL, with the goal of facilitating accurate prognostic stratification and potential individualized treatment strategies. Compared with patients with CD5 - DLBCL, older age, advanced stage, higher incidence of central nervous system involvement, and MYC/BCL-2 and p53 overexpression were more prevalent in CD5 + DLBCL. Most patients with CD5 + DLBCL had lymph nodes with non-germinal center B-cell-like or activated B-cell-like subtype according to immunohistochemistry or Lymph2Cx assay. Next-generation sequencing showed that the proportion of MCD subtype (based on the co-occurrence of MYD88 and CD79B mutations) in the CD5 + DLBCL cohort was higher than that in the CD5 - DLBCL cohort (54.2% vs. 13.0%, P =0.005). Compared with the CD5 - cohort, CD5 + DLBCL patients showed poor 5-year overall survival (70.9% vs. 39.0%, P <0.001). Kaplan-Meier survival analysis indicated that cell of origin, MYC/BCL-2, p53, and BCL-6 expression did not have a prognostic impact on patients with CD5 + DLBCL. Multivariate analysis showed that age above 76 years, advanced stage, higher incidence of central nervous system involvement, and hypoalbuminemia were independent factors for poor prognosis in CD5 + DLBCL patients. In summary, CD5 + DLBCL displays poor prognosis, distinctive clinicopathologic characteristics and predominant genetic features of activated B-cell-like and MCD subtypes with worse survival outcome.

l-Asparaginase synergizes with etoposide via the PI3K/Akt/mTOR pathway in Epstein-Barr virus-positive Burkitt lymphoma.

Burkitt lymphoma (BL) is an aggressive Epstein-Barr virus (EBV)-driven B-cell lymphoma characterized by the translocation and rearrangement of the c-Myc proto-oncogene. High-intensity multidrug chemotherapy regimens have a limited effect on the survival of refractory or relapsed BL patients, mainly owing to the high EBV load and drug resistance. l-asparaginase ( l-Asp) and etoposide (VP-16) play a beneficial role in EBV-related lymphoproliferative diseases; however, their roles and mechanisms in BL remain unclear. In this study, we found that VP-16 inhibited BL cell proliferation and arrested the cell cycle at the G2 /M phase. It also induced autophagy and activated the extrinsic and intrinsic apoptotic signaling pathways in BL cells. Mechanistically, VP-16 inhibited c-Myc expression and regulated the PI3K/Akt/mTOR signaling pathway. Notably, VP-16 also showed a specific synergistic effect with l-Asp to induce apoptosis in EBV-positive BL cells but not in EBV-negative BL cells. VP-16 combined with l-Asp further inhibited c-Myc expression and downregulated the PI3K/Akt/mTOR signaling pathway. Additionally, we found that VP-16 inhibited the expression of latent membrane protein 1 (LMP1), and in combination with l-Asp further decreased LMP1 expression in Raji cells. Our in vivo data also showed that the dual-drug combination significantly inhibited the growth of BL tumors and prolonged the survival of mice compared to VP-16 alone. In conclusion, this study provides new evidence that l-Asp may enhance the antitumor effect of VP-16 by inhibiting the PI3K/Akt/mTOR signaling pathway in EBV-positive BL cells.

Anti-PD-1 Therapy Enhances the Efficacy of CD30-Directed Chimeric Antigen Receptor T Cell Therapy in Patients With Relapsed/Refractory CD30+ Lymphoma.

Anti-CD30 CAR-T is a potent candidate therapy for relapsed/refractory (r/r) CD30+ lymphomas with therapy limitations, and the efficacy needed to be further improved. Herein a multi-center phase II clinical trial (NCT03196830) of anti-CD30 CAR-T treatment combined with PD-1 inhibitor in r/r CD30+ lymphoma was conducted. After a lymphocyte-depleting chemotherapy with fludarabine and cyclophosphamide, 4 patients in cohort 1 and 3 patients in cohort 2 received 106/kg and 107/kg CAR-T cells, respectively, and 5 patients in cohort 3 received 107/kg CAR-T cells combined with anti-PD-1 antibody. The safety and the efficacy of CAR-T cell therapy were analyzed. Cytokine release syndrome (CRS) was observed in 4 of 12 patients, and only 1 patient (patient 9) experienced grade 3 CRS and was treated with glucocorticoid and tocilizumab. No CAR-T-related encephalopathy syndrome was observed. Only two patients in cohorts 2 and 3 experienced obviously high plasma levels of IL-6 and ferritin after CD30 CAR-T cell infusion. The overall response rate (ORR) was 91.7% (11/12), with 6 patients achieving complete remission (CR) (50%). In cohorts 1 and 2, 6 patients got a response (85.7%), with 2 patients achieving CR (28.6%). In cohort 3, 100% ORR and 80% CR were obtained in 5 patients without ≥3 grade CRS. With a median follow-up of 21.5 months (range: 3-50 months), the progression-free survival and the overall survival rates were 45 and 70%, respectively. Of the 11 patients who got a response after CAR-T therapy, 7 patients (63.6%) maintained their response until the end of follow-up. Three patients died last because of disease progression. Taken together, the combination of anti-PD-1 antibody showed an enhancement effect on CD30 CAR-T therapy in r/r CD30+ lymphoma patients with minimal toxicities.

A Novel Prognostic Index Model for Adult Hemophagocytic Lymphohistiocytosis: A Multicenter Retrospective Analysis in China.

Hemophagocytic lymphohistiocytosis (HLH) is an immune disorder with rapid progression and poor survival. Individual treatment strategy is restricted, due to the absence of precise stratification criteria. In this multicenter retrospective study, we aimed to develop a feasible prognostic model for adult HLH in China. A total of 270 newly diagnosed patients of adult HLH were retrieved from the Huaihai Lymphoma Working Group (HHLWG), of whom 184 from 5 medical centers served as derivation cohort, and 86 cases from 3 other centers served as validation cohort. X-Tile program and Maxstat analysis were used to identify optimal cutoff points of continuous variables; univariate and multivariate Cox analyses were used for variable selection, and the Kaplan-Meier curve was used to analyze the value of variables on prognosis. The C-index, Brier Score, and calibration curve were used for model validation. Multivariate analysis showed that age, creatinine, albumin, platelet, lymphocyte ratio, and alanine aminotransferase were independent prognostic factors. By rounding up the hazard ratios from 6 significant variables, a maximum of 9 points was assigned. The final scoring model of HHLWG-HPI was identified with four risk groups: low risk (≤3 pts), low-intermediate risk (4 pts), high-intermediate risk (5-6 pts), and high risk (≥7 pts), with 5-year overall survival rates of 68.5%, 35.2%, 21.3%, and 10.8%, respectively. The C-indexes were 0.796 and 0.758 in the derivation and validation cohorts by using a bootstrap resampling program. In conclusion, the HHLWG-HPI model provides a feasible and accurate stratification system for individualized treatment strategy in adult HLH.

The Acetyltransferase KAT5 Inhibitor NU 9056 Promotes Apoptosis and Inhibits JAK2/STAT3 Pathway in Extranodal NK/T Cell Lymphoma.

BACKGROUND: Extranodal natural killer/T cell lymphoma (ENKTL) is an aggressive malignant non- Hodgkin's lymphoma (NHL) with a poor prognosis. Therefore, novel therapeutic biomarkers and agents must be identified for the same. KAT5 inhibitor, NU 9056, is a small molecule that can inhibit cellular proliferation; however, its role in ENKTL has not been studied. OBJECTIVE: The present study investigated the effect of NU 9056 in ENKTL cells and explored the possible molecular mechanism for its antitumour effect. METHODS: The role of NU 9056 in ENKTL cells was investigated through the Cell Counting Kit-8 assay, flow cytometry, Western blot, and real-time quantitative polymerase chain reaction assay. RESULTS: NU 9056 inhibited ENKTL cell proliferation and induced G2/M phase arrest. NU 9056 also induced apoptosis by upregulating DR4, DR5, and caspase 8 expressions. Additionally, NU 9056 increased the expression of Bax, Bid, and cytochrome C and decreased the expression of Bcl-2, Mcl-1, and XIAP. Furthermore, NU 9056 activated endoplasmic reticulum (ER) stress and inhibited the JAK2/STAT3 signalling pathway. The p38 mitogen-activated protein kinase (MAPK) signalling pathway was also activated by NU 9056, and the ERK signalling pathway was suppressed in natural killer/T cell lymphoma cells. CONCLUSION: NU 9056 inhibited cell proliferation, arrested cell cycle in the G2/M phase, and induced apoptosis through the stimulation of ER stress, thus inhibiting the JAK2/STAT3 signalling pathway and regulating MAPK pathways in ENKTL cells.

Humanized Anti-CD19 CAR-T Cell Therapy and Sequential Allogeneic Hematopoietic Stem Cell Transplantation Achieved Long-Term Survival in Refractory and Relapsed B Lymphocytic Leukemia: A Retrospective Study of CAR-T Cell Therapy.

Early response could be obtained in most patients with relapsed or refractory B cell lymphoblastic leukemia (R/R B-ALL) treated with chimeric antigen receptor T-cell (CAR-T) therapy, but relapse occurs in some patients. There is no consensus on treatment strategy post CAR-T cell therapy. In this retrospective study of humanized CD19-targeted CAR-T cell (hCART19s) therapy for R/R B-ALL, we analyzed the patients treated with allogeneic hematopoietic stem cell transplantation (allo-HSCT) or received a second hCART19s infusion, and summarized their efficacy and safety. We retrospectively studied 28 R/R B-ALL patients treated with hCART19s in the Affiliated Hospital of Xuzhou Medical University from 2016 to 2020. After the first hCART19s infusion, 10 patients received allo-HSCT (CART+HSCT group), 7 patients received a second hCART19s infusion (CART2 group), and 11 patients did not receive HSCT or a second hCART19s infusion (CART1 group). The safety, efficacy, and long-term survival were analyzed. Of the 28 patients who received hCART19s treatment, 1 patient could not be evaluated for efficacy, and 25 (92.6%) achieved complete remission (CR) with 20 (74.7%) achieving minimal residual disease (MRD) negativity. Seven (25%) patients experienced grade 3-4 CRS, and one died from grade 5 CRS. No patient experienced ≥3 grade ICANS. The incidence of second CR is higher in the CART+HSCT group compared to the CART2 group (100% vs. 42.9%, p=0.015). The median follow-up time was 1,240 days (range: 709-1,770). Significantly longer overall survival (OS) and leukemia-free survival (LFS) were achieved in the CART+HSCT group (median OS and LFS: not reached, p=0.006 and 0.001, respectively) compared to the CART2 group (median OS: 482; median LFS: 189) and the CART1 group (median OS: 236; median LFS: 35). In the CART+HSCT group, the incidence of acute graft-versus-host disease (aGVHD) was 30% (3/10), and transplantation-related mortality was 30% (3/10). No chronic GVHD occurred. Multivariate analysis results showed that blasts ≥ 20% in the bone marrow and MRD ≥ 65.6% are independent factors for inferior OS and LFS, respectively, while receiving allo-HSCT is an independent factor associated with both longer OS and LFS. In conclusion, early allo-HSCT after CAR-T therapy can achieve long-term efficacy, and the adverse events are controllable.

Risk stratification model based on VEGF and International Prognostic Index accurately identifies low-risk diffuse large B-cell lymphoma patients in the rituximab era.

Vascular endothelial growth factor affects the invasiveness of solid tumors by regulating angiogenesis. However, it is not clear whether VEGF could be used to predict the prognosis of DLBCL in the era of rituximab-based immunotherapy. We conducted a retrospective study to explore response to therapy and the prognostic value of VEGF on DLBCL in the rituximab era. The subjects were 65 patients with a histological diagnosis of DLBCL from the Affiliated Hospital of Xuzhou Medical University. Kaplan-Meier analysis was performed to estimate the cumulative survival rate of patients with different VEGF and IPI levels, and comparisons between groups were made using the log-rank test. DLBCL patients with elevated VEGF were more likely to have extranodal involvement, advanced stage, Myc/Bcl-2 double expression, and a higher Ki-67 score. Elevated VEGF was associated with poor therapeutic response and survival. When patients were divided into low, low-intermediate, high-intermediate and high-risk groups using the V-IPI model based on VEGF and IPI, PFS rates were 94.4, 74.1, 40.6 and 14.8%, respectively. This model better identified low-risk patients than IPI (85.9, 88.9, 37 and 7.8%). Our results demonstrate that VEGF predicts therapeutic response in DLBCL and the V-IPI model accurately predicts PFS of low-risk DLBCL in the rituximab era.

EHMT2 inhibitor BIX-01294 induces endoplasmic reticulum stress mediated apoptosis and autophagy in diffuse large B-cell lymphoma cells.

Despite advancement in the treatment of diffuse large B-cell lymphoma (DLBCL), many patients tend to relapse or become refractory after initial therapy. Therefore, it is essential to identify novel therapeutic targets and drugs, understand the molecular pathogenesis mechanism of DLBCL, and find ways to prevent and treat relapsed or refractory DLBCL. BIX-01294 is a small molecule compound that specifically inhibits EHMT2 activity. In this study, we demonstrate that BIX-01294 triggered the inhibition of human DLBCL cell proliferation, lead to G1 phase arrest via increasing P21 level and reducing cyclin E level. BIX-01294 also induced apoptosis via endogenous and exogenous apoptotic pathways. Moreover, BIX-01294 triggered autophagy and activated ER stress in human DLBCL cells. Furthermore, we showed that both key components of ER stress, ATF3, and ATF4, are required for BIX-01294-induced apoptosis and autophagy. Hence, this study provides new evidence that EHMT2 may be a new therapeutic target, and BIX-01294 may be a potential therapeutic drug for treating DLBCL.

Kinetics of immune reconstitution after anti-CD19 chimeric antigen receptor T cell therapy in relapsed or refractory acute lymphoblastic leukemia patients.

INTRODUCTION: Anti-CD19 chimeric antigen receptor (CAR) -T cells, which recognize and kill both B lymphoblasts and normal B cells, result in B cell aplasia and humoral immunodeficiency. However, there were only a few detailed reports on the profile of immune reconstitution after anti-CD19 CAR-T cell therapy. METHODS: Thirty nine patients with relapsed or refractory (R/R) B cell acute lymphoblastic leukemia (ALL) receiving anti-CD19 CAR-T cell therapy were enrolled. Subjects died, relapsed, received other treatment, or lost to follow-up within 60 days post-infusion were excluded. 21 patients were finally selected. Laboratory and clinical data were collected for analysis of immune reconstitution. RESULTS: CD8+ cells were the first to recover with a median time on day 21(7-87), followed by CD16/CD56+ cells on day 28(14-87), and finally CD4+ cells with only 5(23.81%) patients recovered within 60 days post-infusion. CD4/CD8 ratio was inverted, sustaining for at least 1 year. B cell aplasia occurred in all patients and CD19+ cells returned to normal on a median time of day 79(41-118). All patients developed hypogammaglobulinemia with a median onset time of 2 weeks post-infusion. IgG recovered in 6 patients with a median time on day 184(89-346). IgM recovered on days 212, 242, and 346 in 3 patients. IgA recovered most slowly and remained low >1 year postinfusion. A total of 9 infections occurred in 6(28.57%) patients. CONCLUSIONS: Our data showed prolonged reconstitution of immune function, especially humoral immunity, in R/R B cell ALL patients receiving anti-CD19 CAR-T cell therapy.

Cladribine Induces ATF4 Mediated Apoptosis and Synergizes with SAHA in Diffuse Large B-Cell Lymphoma Cells.

Cladribine is a purine nucleoside analog used to treat B-cell chronic lymphocytic leukemia and hairy cell leukemia, also functions as an inhibitor of DNA synthesis to block the repair of the damaged DNA. The therapeutic role of cladribine against diffuse large B-cell lymphoma cells (DLBCL) is still undefined. In the present study, we demonstrated that cladribine inhibited cell proliferation and induced G1 phase arrest in human DLBCL cells. Furthermore, we showed that cladribine induced apoptosis by decreasing the expression of c-FLIPL and increasing the expression of DR4 and the cleaved form of caspase8. Cladribine also upregulated the expression of Bax, and downregulated the expression of Mcl-1 and Bcl-2 in a dose-dependent manner. It also activated endoplasmic reticulum (ER) stress, and ATF4 expression was required for cladribine induced apoptosis. Also, we showed that suberoylanilide hydroxamic acid (SAHA) enhanced the pro-apoptotic role of cladribine. Collectively, cladribine activated extrinsic and intrinsic apoptotic signaling pathways via stimulating ER stress signaling pathway and eliciting synergistic effect with SAHA in DLBCL cells.

Phase II trial of co-administration of CD19- and CD20-targeted chimeric antigen receptor T cells for relapsed and refractory diffuse large B cell lymphoma.

PURPOSE: Anti-CD19 chimeric antigen receptor T (CAR-T) cell therapy has demonstrated remarkable efficacy for refractory and relapsed diffuse large B cell lymphoma (R/R DLBCL). However, this therapy failed in nearly 25% patients mainly due to antigen loss. The authors performed a phase Ⅱ trial by coadministration of anti-CD19 and anti-CD20 CAR-T cells treatment for R/R DLBCL and evaluated its efficacy and toxicity. METHODS: Totally 21 patients with DLBCL were enrolled in this study. The patients were conditioned with fludarabine and cyclophosphamide before the infusion of anti-CD19 and anti-CD20 CAR-T cells. Treatment response, toxicity, and persistence were monitored continuously. RESULTS: Of the 21 patients received the treatment, the objective response rate (ORR) is 81.0% (95% confidence interval [CI], 58.1%-94.6%) with four cases of bulk (4/5) and one case of testis involvement; 52.4% (95% CI, 29.8%-74.3%) had a complete response (CR). Peak levels of anti-CD19 and anti-CD20 CAR cells were associated with response (P = .007 and .002). Grade 3-4 cytokine release syndrome (CRS) and neurologic events occurred in 28.5% and 9.5% patients, respectively. Median overall survival (OS) and progression-free survival (PFS) were 8.1 and 5.0 months, respectively. The maximum standard uptake value (SUVmax) of CD4/CD8 ratio before and after infusion were associated with responses, and the total lesion glycolysis (TLG) before infusion correlates with cytokines level. CONCLUSIONS: Coadministration of anti-CD19 and CD20 CAR-T cells therapy for DLBCL is feasible with manageable toxicity. Cytokine markers are related to toxicity and SUVmax could predict efficacy. This trial was registered at www.clinicaltrials.gov as NCT03207178.

Study on the Reducing Injection Pressure Regulation of Hydrophobic Carbon Nanoparticles.

The interest in the application of nanofluid in reducing injection pressure has been increasing especially for tight reservoirs. In this work, a new type of hydrophobic carbon nanofluid was prepared and the pressure-reducing performance was investigated. The results of particle size distribution, zeta potential, and transmission electron microscopy image showed that the dispersion of nanofluid was uniform and stable. In addition, the hydrophobic carbon nanofluid showed excellent antitemperature and antisalinity property. The contact angle of oil-wet glass slide can range from 45 to 89° after it adsorbs hydrophobic carbon nanoparticles (HCNPs). The atomic force microscope tests showed that the core surface roughness was reduced about 16.67%. The core flooding tests showed that the pressure-reducing rate of 0.15 wt % HCNP nanofluid can reach 17.00%. HCNPs show good performance in reducing pressure and have a broad application prospect in oil field development.

[Significance of Peripheral Blood Lymphatic to Monocyte Ratio in the Progress of PGI-DLBCL].

OBJECTIVE: To explore the significance of lymphocyte to monocyte ratio (LMR) in the disease progress of primary gastrointestinal diffuse large B-cell lymphoma (PGI-DLBCL). METHODS: The clinical data of 43 patients diagnosed as PGI-DLBCL in our hospital from January 2011 to December 2015 were collected, and the disease progress was followed up. RESULTS: According to the ROC curve, the threshold value of LMR for 2 years PFS (%) of PGI-DLBCL patients was 2.6. Unvariate analysis showed that LMR (P＜0.05), large enclosed mass lesion (P＜0.01) and IPI (P＜0.05) were prognostic factors affecting PFS, the COX regression model multivariate analysis showed that LMR＜2.6 [ (risk ratio (RR)=3.083, 95%CI 1.828-8.313, P＜0.01], and large enclosed mass lesions (RR=2.718, 95%CI 1.339-6.424, P＜0.05) were the independent adverse prognostic factor for two years PFS. CONCLUSION: Both LMR＜2.6 and large enclosed mass lesions relate with the progress of PGI-DLBCL.

A Study on Preparation and Stabilizing Mechanism of Hydrophobic Silica Nanofluids.

Nanofluids have increasingly drawn interest in recent years with their various applications in a number of fields. The method for the preparation of stable nanofluids is a key concern for extending the application of nanofluids. This study focuses on the effect of pH, dosage of surfactant (TX-100), and nanofluid concentration on the stability of a silica nanofluid. Particle size and zeta potential are two important factors to consider in evaluating the stability of the silica nanofluid. Results indicate that the stability of the silica nanofluid highly depends on pH, dosage of surfactant (TX-100), and nanofluid concentration. On the basis of these experiments, the best conditions for the preparation of a silica nanofluid are 0.1 wt. % for the concentration of silica nanoparticles and TX-100 and 10 for pH. A transparent and stable silica nanofluid can thus be obtained.

[Effect of OCT4A Gene on the Biological Characteristics of K562 Cells].

OBJECTIVE: To evaluate biological effects of OCT4A gene on K562 cells and explore the molecular mechanism of K562 cell apoptosis. METHODS: Two recombinant lentiviral vectors were constructed, which could stablely up- regulate and down- regulate OCT4A protein. Recombinant lentivirus was generated by co-transfection of three-plasmids and transfec-ted into K562 cells. The experiments were divided into 5 groups: normal, pLVX-OCT4A-ZsGreen1, pLVX vector control, PLB-OCT4A shRNA and non-specific shRNA groups. Western blot was applied to detect the expression of OCT4A protein, the cell counting kit-8 was applied to evaluate the effect of OCT4A on proliferation of K562 cells. The apoptosis and differentiation of K562 cells were detected by flow cytometry with AnnexinV/7-AAD double staining. The mRNA expressions of caspase-3,BIM,BCL-xL,BAX in K562 cells were determined by real time PCR. RESULTS: The OCT4A fragment was amplified by reverse transcription polymerase chain reaction(RT-PCR), the 2 lentiviral vectors were successfully constructed. In comparson with those in the control group, the expression of OCT4A protein of pLVX-OCT4A-ZsGreen1 group was significantly increased, but decreased in PLB-OCT4A shRNA group. CCK-8 assay showed that the higher the content of OCT4A protein, the faster the cell proliferation. The apoptosis rate was (3.48±0.52)% of pLVX-OCT4A-ZsGreen1 group, which was lower than that of control group, while the apoptosis rate PLB-OCT4A shRNA group was (7.25±0.57)%, which was higher than that of control group (P<0.05), however, the K562 cells differentiation was not influenced(P>0.05). Compared with control group, the gene expression of Caspase-3,BIM and BAX was down-regulated(P>0.05), but a significant up-regulation of BCL-xL gene expression was observed(P<0.05). CONCLUSION: Two lentiviral vectors have been successfully constructed, which can stably up- and down- regulate the expression of OCT4A in K562 cells respectively. OCT4A can promote the K562 cell proliferation and inhibit the apoptosis, the mechanism may be related with up-regulation of BCL-xl expression.

[Establishment and Identification of Mouse Model of Philadelphia Chromosome Positive Acute Lymphoblastic Leukemia].

OBJECTIVE: To establish a mouse model of Ph+ acute lymphoblastic leukemia (ALL) for providing a valuable tool to facilitate the researches on Ph+ ALL. METHODS: CML-like mice were generated by transfection to bone marrow cells of BABL/c with Mig190 retrovirus. The Ph+ ALL mouse model was established by infusion of sorted CML like mouse-derived BCR-ABL+ B cells into the mice of same linege. Immonophenotypes, BCR-ABL transcription and expression of these leukemic cells were detected by flow cytometry, RT-PCR and Western blot respectively. RESULTS: CML-like presentation appeared in the mice after Mig190 virus transfection. After infusion with sorted BCR-ABL+ B cells, all the receipted mice eventually presented the clinical signs of acute leukemia. Flow cytometry analysis showed that these leukemic cells were positive for CD19+; both RT-PCR and Western blot indicated that this mouse model is consistent with Ph+ ALL phenotypecally and molecalarlly. CONCLUSION: A novel method to establish Ph+ ALL mouse model has been developed successfully, and this model can provide useful tool for the study of Ph+ ALL.

[In vitro study of BRD4 inhibitor GSK525762A against primary adult common B-cell acute lymphoblastic leukemia cells in vitro].

OBJECTIVE: To investigate the effects of bromodomain-containing protein 4 (BRD4) inhibitor GSK525762A on the proliferation and apoptosis of primary common B-cell acute lymphoblastic leukemia (common B-ALL) cells from adult patients, then to further explore the possible mechanisms. METHODS: Purified leukemia cells from 14 common B-ALL adult patients (4 Ph⁺ and 10 Ph⁻ cases) were obtained by flow cytometry sorting, and maintained in a mimic bone marrow microenvironment culture system for short-term culture. Leukemia cells were treated with various concentrations of GSK525762A. The inhibitory effects of BRD4 inhibitor on common B-ALL leukemia cells were measured by CCK-8 assay and the apoptosis of those cells was determined by AnnexinⅤ/7-AAD staining using flow cytometry. The transcripts of c-MYC, CDK6 and Bcl-2 were detected by quantitative RT-PCR, and the expression of c-MYC, CDK6 and Bcl-2 proteins were detected via Western blot. RESULTS: GSK525762A could inhibit the proliferation of leukemia cells from all 14 common B-ALL patients in a dose-dependent manner, the median value of IC50 was 256.25 (90.64-1 378.39)nmol/L. GSK525762A could promote cells apoptosis of B-ALL leukemia cells in a dose-dependent manner, the median apoptosis rates respectively were 45.17%(9.38%-70.91%), 66.02% (24.36%-96.34%) and 89.29% (39.29%-99.37%) after treated by 500, 1 000 and 2 500 nmol/L GSK525762A. GSK525762A has a similar effect on Ph⁺ ALL and Ph⁻ B-ALL, but the effect of proliferation inhibition and apoptosis enhancement on Ph+ B-ALL is weaker than that on Ph⁻ B-ALL. Compared with vehicle control group, the levels of c-MYC, Bcl-2 and CDK6 transcripts in leukemic cells were reduced after treatment for 24 h and 48 h by 1 000 nmol/L GSK525762A, and there are no significant differences in the downregulation of c-MYC and CDK6 mRNA between Ph⁺ and Ph⁻ B-ALL; however, the inhibitory effect on Bcl-2 transcription was weaker in Ph⁺ B-ALL cells than that in Ph⁻ B-ALL cells. Moreover, c-MYC, Bcl-2 and CDK6 protein levels decreased in GSK525762A treated group. CONCLUSION: GSK525762A could strongly inhibit the proliferation of common B-ALL and trigger apoptosis; meanwhile it has certain effects against Ph⁺ ALL in vitro. The effect may be achieved by down-regulation of c-MYC, CDK6 and Bcl-2 expression.

[Effects of stromal cells on sentitivity to imatinib in Sup-B15 Philadelphia chromosome positive acute lymphoblastic leukemia cells].

OBJECTIVE: To investigate the sensitivity of imatinib (IM) on Sup-B15 Ph+ acute lmphoblastic leukemia (ALL) cells indused by stromal cells OP9, and to further explore its mechanism. METHODS: The study is divided into two group, Sup-B15 cells group and co-cultured with OP9 cells group (Sup-B15/OP9 group). The inhibitory effects of IM on leukemia cells were measured by CCK-8 test, and the apoptosis by Annexin Ⅴ/7-AAD dyeing and the percentage of CD 34+CD38- leukemia cells were determined by flow cytometry. ALDH1, CD144, and ß-catenin mRNA were detected by real-time RT-PCR, protein levels by Western blot. Inmunoprecipitation was used to detect the level of ß-catenin connected to CD144. RESULTS: IM presented inhibitory effects on Sup-B15 and Sup-B15/OP9 cells at multiple concentrations from 10 µmol/L to 45 µmol/L. The IC50 of IM on Sup-B15/OP and Sup-B15 cells were 35.8 µmol/L and 6.3 µmol/L, respectively (P<0.05). After 24 h of 30 µmol/L IM treatment, the percentages of apoptosis cells in Sup-B15/OP9 and Sup-B 15 cell were (14.24 ± 2.11)% and (3.45 ± 0.68)%, respectively (P<0.05). The percentage of CD34+CD38- cells in Sup-B15/OP9 group was significantly higher than that in Sup-B15 group [(3.42 ± 0.28)% vs (0.16 ± 0.15)%, P<0.05]. As compared to Sup-B15 cells, the transcription of ALDH1 in Sup-B15/OP9 group was remarkably upregulated (0.097 ± 0.012 vs 0.046 ± 0.010, P<0.05), and the CD133 protein level was also upregulated in Sup-B15/OP9 group. The transcription of CD144 in Sup-B15/OP9 group was remarkably upregulated compared with Sup-B15 group (0.103 ± 0.015 vs 0.010±0.003, P<0.05), as well as the CD144 protein. ß-catenin mRNA transcription has no obvious changes between Sup-B15 group and Sup-B15/OP9 group (P>0.05), while the whole ß-catenin protein and the cell nucleus ß-catenin significantly increased, as well as the ß-catenin protein combined with CD144. CONCLUSION: Co-cultured with OP9 cells, Sup-B15 cells show less sensitivity to imatinib. The raising activity of CD144 and CD144/ß-catenin signaling may work in this procession.

[Effect of Metformin on Proliferation, Differentiation and Apoptosis of THP-1 Cells].

OBJECTIVE: To investigate the effect of metformin on proliferation, differentiation and apoptosis of THP-1 cells and explore its possible mechanism. MEHODS: THP-1 cells were cultured with different concentrations of metformin for 24 h and 48 h. The cell proliferation was evaluated by CCK-8, the cell apoptosis was analyzed by Annexin V/7-AAD double labeling, the expression of CD14 and CD11b (surface differentiation antigens on THP-1 cells) was evaluated by flow cytometry, the BCL-XL, BAX, BIM and caspase-3 mRNA expressions of THP-1 cells were detected by real time quantitative PCR. RESULTS: Metformin could significantly inhibit the growth of THP-1 cells in a time- and dose- dependent manner. After treated with 20 mmol/L metformin for 24 h, the expressions of CD14 and CD11b in THP-1 cells didn't change much (P>0.05), the early apoptosis rates in exprimental and control groups were (2.02±0.85)% and (4.46±1.33)% respectively, the late apoptosis rates in experimental and control groups were (1.43±0.83)% and (3.31±0.59)% respectively. In process of inducing effect of 20 mmol/L metformin on THP-1 cells, the expressions of BCL-XL and BIM did not significantly changed, while the expressions of BAX and caspase-3 significantly increased (P<0.01). CONCLUSION: Metformin can effectively inhibit proliferation and induce apoptosis of THP-1 cells. However, it has no significant effect on differentiation of THP-1 cells, its mechanism inducing apoptosis maybe related with up-regulating BAX and caspase-3.