MYC Protein Expression in Primary Diffuse Large B-Cell Lymphoma of the Central Nervous System

Primary diffuse large B-cell lymphoma of the central nervous system (CNS DLBCL) is a rare, aggressive subtype of DLBCL, the biology of which is poorly understood. Recent studies have suggested a prognostic role of MYC protein expression in systemic DLBCL, but little is known about the frequency and significance of MYC protein expression in CNS DLBCL. Hence, we investigated MYC protein expression profiles of CNS DLBCL and assessed the relationship between MYC expression and a variety of histopathologic, immunophenotypic, genetic, and clinical features. Fifty-nine CNS DLBCL diagnosed at our institution over the past 13 years were evaluated. The majority of cases (80%) showed centroblastic morphology, and 12 (20%) displayed a perivascular pattern of infiltration. According to the Hans criteria, 41 (69%) cases had a non-germinal center B-cell and 18 (31%) had a germinal center B-cell cell-of-origin (COO) phenotype. Mean MYC protein expression was 50% (median: 50%, range: 10-80%). Forty-three cases (73%) showed MYC overexpression (≥40%), and 35 (60%) showed MYC/BCL2 coexpression. MYC overexpression was seen in the single case harboring MYC translocation and in the cases showing increased copies of MYC (27%); however, no significant difference in mean MYC expression was seen between groups harboring or lacking MYC aberrations. In our series, age was associated with a significantly increased risk of death, and the perivascular pattern of infiltration was associated with a significantly increased risk of disease progression. Neither MYC expression (with or without BCL2 coexpression) nor other variables, including COO subtype were predictive of clinical outcome. Our findings indicate that the proportion of CNS DLBCL overexpressing MYC is higher compared to systemic DLBCL, and MYC overexpression appears to be independent of genetic MYC abnormalities. Thus, MYC expression and other immunophenotypic markers used for prognostication of systemic DLBCL might not apply to CNS DLBCL due to differences in disease biology.     

Expression of DBC1 and Androgen Receptor Predict Poor Prognosis in Diffuse Large B Cell Lymphoma

BACKGROUND: Recently, deleted in breast cancer 1 (DBC1) has been suggested as a poor prognostic indicator of various human cancers and may possibly have a role as a coactivator of androgen receptor (AR). However, their roles in lymphoma are still unknown. MATERIALS AND METHODS: We investigated the effect of the expression of DBC1 and AR in diffuse large B cell lymphoma (DLBCL). Immunohistochemical expression of DBC1 and AR were evaluated in 101 DLBCL samples by tissue microarray. RESULTS: Positive expression of DBC1 and AR was seen in 73% and 70% of DLBCL, respectively. In total DLBCL patients, DBC1 and AR expression were significantly associated with high clinical stage, elevated serum lactate dehydrogenase levels, and high international prognostic index scores, and they predicted shorter overall survival (OS) and relapse-free survival (RFS) by univariate analysis. DBC1 expression was also an independent prognostic indicator by multivariate analysis (OS, P = .017; RFS, P = .004). Especially, both DBC1 and AR expression significantly correlated with shorter OS and RFS in non-germinal center B cell (non-GCB)-type DLBCL by univariate analysis. In multivariate analysis, DBC1 expression was an independent prognostic predictor for OS (P = .035) and AR expression significantly correlated with RFS (P = .005). CONCLUSION: We demonstrate that the expression of DBC1 and AR are significant prognostic indicators for DLBCL patients, especially for unfavorable non-GCB-type DLBCL.     

The Cdc20-binding Phe Box of the Spindle Checkpoint Protein BubR1 Maintains the Mitotic Checkpoint Complex During Mitosis

The spindle checkpoint ensures accurate chromosome segregation by monitoring kinetochore-microtubule attachment. Unattached or tensionless kinetochores activate the checkpoint and enhance the production of the mitotic checkpoint complex (MCC) consisting of BubR1, Bub3, Mad2, and Cdc20. MCC is a critical checkpoint inhibitor of the anaphase-promoting complex/cyclosome, a ubiquitin ligase required for anaphase onset. The N-terminal region of BubR1 binds to both Cdc20 and Mad2, thus nucleating MCC formation. The middle region of human BubR1 (BubR1M) also interacts with Cdc20, but the nature and function of this interaction are not understood. Here we identify two critical motifs within BubR1M that contribute to Cdc20 binding and anaphase-promoting complex/cyclosome inhibition: a destruction box (D box) and a phenylalanine-containing motif termed the Phe box. A BubR1 mutant lacking these motifs is defective in MCC maintenance in mitotic human cells but is capable of supporting spindle-checkpoint function. Thus, the BubR1M-Cdc20 interaction indirectly contributes to MCC homeostasis. Its apparent dispensability in the spindle checkpoint might be due to functional duality or redundant, competing mechanisms.     

CTLA-4在弥漫大B细胞淋巴瘤患者外泌体的表达及初步机制研究

摘要 目的：探讨细胞毒性T淋巴细胞相关抗原4（CTLA-4）在弥漫大B细胞淋巴瘤（DLBCL）患者外泌体的表达及初步机制。方法：2019年6月至2020年11月就诊于本院的DLBCL患者纳入本项研究,分为缓解组和复发组;选取来医院体检的健康志愿者做为对照组;采用试剂盒分离外泌体,CD63抗体包被磁珠结合后,流式细胞术检测CTLA-4+外泌体的比例;流式细胞术检测CD4⁺T细胞、CD8⁺T细胞和调节性T细胞（Treg细胞）的比例。结果：相对于对照组,缓解组DLBCL患者CTLA-4+外泌体的比例升高了37.42%;复发组DLBCL患者CTLA-4+外泌体的比例为6.04%,相对于缓解组,差异具有显著的统计学意义;复发组DLBCL患者CD4/CD8⁺T细胞比值和Treg细胞比例分别为0.85和0.44%,相对于缓解组,差异均具有显著的统计学意义;相关性分析结果显示CTLA-4+外泌体比例与CD4/CD8⁺T细胞比值呈负相关,而与Treg细胞比例呈正相关。结论：CTLA-4+外泌体比例在DLBCL患者显著升高,且与淋巴瘤的治疗效果和抗肿瘤免疫反应均具有紧密的相关性。     

利妥昔单抗联合化疗治疗弥漫型大B细胞淋巴瘤患者的临床研究

目的:探讨利妥昔单抗与化疗相结合治疗弥漫型大B细胞淋巴瘤(diffuse large Bcelllymphoma,DLBCL)患者的可行性。方法:选取2002年1月至2011年5月我院收治的84例CD20阳性的DLBCL患者,采用利利妥昔单抗与化疗相结合的方法治疗,对其疗效及安全性进行评价,并对其影响因素进行分析。结果:有56例患者治疗艹6个周期,占66.67%;有28例患者治疗6个周期,占33.33%。84例患者治疗的总有效率为83.33%。其中,初治组的总有效率为91.67%,明显高于复治组的62.5%,差异有统计学意义(P0.05)。红细胞沉降率、国际预后指数评分、是否为初治、是否存在B症状以及利妥昔单抗的治疗周期等变量成为影响治疗效果的独立危险因素(P0.05)。随访5年,治疗后第l年、2年、3年和5年患者的生存率分别为88.1%(74/84)、72.62%(61/84)、60.71%(51/84)、60.71%(51/84)。国际预后指数评分、利妥昔单抗的治疗周期以及治疗效果等变量是影响患者生存的独立危险因素(P0.05)。结论:对于弥漫型大B细胞淋巴瘤患者尤其是对初治患者而言,利妥昔单抗联合化疗治疗具有更好的治疗效果,临床应用时不会加重患者的不良反应。     

Ezrin在化疗敏感性不同大B细胞淋巴瘤中表达的实验研究

目的：比较化疗敏感性不同弥漫性大B细胞淋巴瘤的蛋白质表达差异,寻找可反映大B细胞淋巴瘤化疗敏感性的标志物。方法：通过肿瘤药物敏感试验选取化疗高敏感性和低敏感性大B细胞淋巴瘤组织,进行蛋白质组学比较研究后得出差异表达蛋白;对在高敏感组中高表达的埃兹蛋白（Ezrin）进一步行免疫印迹验证,应用免疫组化技术检测在临床病例中的表达情况。结果：建立了化疗高敏感和低敏感大B细胞淋巴瘤差异表达蛋白质凝胶2D图谱,鉴定了28种差异表达蛋白,发现Ezrin蛋白在化疗高敏感组表达高于低敏感组,免疫印迹和免疫组化结果也进一步证实了Ezrin的这一表达状态。结论：Ezrin蛋白表达在化疗敏感性不同大B细胞淋巴瘤中存在差别,可能作为预测淋巴瘤化疗敏感性的候选标志物。     

Ran GTPase-Activating Protein 1 Is a Therapeutic Target in Diffuse Large B-Cell Lymphoma

Lymphoma-specific biomarkers contribute to therapeutic strategies and the study of tumorigenesis. Diffuse large B-cell lymphoma (DLBCL) is the most common type of malignant lymphoma. However, only 50% of patients experience long-term survival after current treatment; therefore, developing novel therapeutic strategies is warranted. Comparative proteomic analysis of two DLBCL lines with a B-lymphoblastoid cell line (LCL) showed differential expression of Ran GTPase-activating protein 1 (RanGAP1) between them, which was confirmed using immunoblotting. Immunostaining showed that the majority of DLBCLs (92%, 46/50) were RanGAP1⁺, while reactive lymphoid hyperplasia (n = 12) was RanGAP1⁺ predominantly in germinal centers. RanGAP1 was also highly expressed in other B-cell lymphomas (BCL, n = 180) with brisk mitotic activity (B-lymphoblastic lymphoma/leukemia: 93%, and Burkitt lymphoma: 95%) or cell-cycle dysregulation (mantle cell lymphoma: 83%, and Hodgkin’s lymphoma 91%). Interestingly, serum RanGAP1 level was higher in patients with high-grade BCL (1.71 ± 2.28 ng/mL, n = 62) than in low-grade BCL (0.75 ± 2.12 ng/mL, n = 52) and healthy controls (0.55 ± 1.58 ng/mL, n = 75) (high-grade BCL vs. low-grade BCL, p = 0.002; high-grade BCL vs. control, p < 0.001, Mann-Whitney U test). In vitro, RNA interference of RanGAP1 showed no effect on LCL but enhanced DLBCL cell death (41% vs. 60%; p = 0.035) and cell-cycle arrest (G0/G1: 39% vs. 49%, G2/M: 19.0% vs. 7.5%; p = 0.030) along with decreased expression of TPX2 and Aurora kinases, the central regulators of mitotic cell division. Furthermore, ON 01910.Na (Estybon), a multikinase inhibitor induced cell death, mitotic cell arrest, and hyperphosphorylation of RanGAP1 in DLBCL cell lines but no effects in normal B and T cells. Therefore, RanGAP1 is a promising marker and therapeutic target for aggressive B-cell lymphoma, especially DLBCL.     

ICE方案治疗复发难治性非霍奇金弥漫大B细胞淋巴瘤临床观察

目的:观察ICE方案(异环磷酰胺IFO,卡铂CBP,依托泊苷VP-16)治疗复发/难治性非霍奇金弥漫大B细胞淋巴瘤(Non-hodgkin's lymphoma,NHL)的疗效及安全性。方法:20例经系统化疗后复发或进展的非霍奇金弥漫大B细胞淋巴瘤(DLBCL)患者,采用ICE方案化疗至少2周期,IFO 5 g/m2,第2天,持续24小时静脉输注,CBP按AUC=5,max 800 mg,第2天,静脉输注,VP-16.100 mg/m2,第1-3天,静脉输注。结果:完全缓解(complete response,CR)5例,部分缓解(partial response,PR)8例,疾病稳定(stable disease,SD)4例,疾病进展(progress disease,PD)3例,总有效率(overall response rate,ORR,CR+PR)65%,化疗副作用主要为骨髓抑制(Ⅰ、Ⅱ度6例,Ⅲ、Ⅳ度14例),其他不良反应包括胃肠道反应、粘膜损伤、肝肾毒性及脱发等均可耐受。结论:ICE方案可用于非霍奇金弥漫大B细胞淋巴瘤的二线化疗方案。     

初探Septin 9作为大B细胞淋巴瘤化疗敏感性相关标志物

目的：初步探讨Septin 9作为大B细胞淋巴瘤化疗敏感性相关标志物的实验依据。方法：通过肿瘤药物敏感试验选取化疗高敏感性和低敏感性大B细胞淋巴瘤组织,进行蛋白质组学比较研究后得出差异表达蛋白;对在低敏感组中高表达的Septin 9进一步行Western Blot验证,应用免疫组化技术检测Septin 9在临床病例中的表达情况。结果：化疗高敏感性和低敏感性大B细胞淋巴瘤组织蛋白质组学比较研究显示Septin 9蛋白在高敏感组表达低于低敏感组,免疫印迹和免疫组化结果与蛋白质组结果是一致的。结论：Septin 9蛋白表达在化疗敏感性不同大B细胞淋巴瘤中存在差别,存在化疗敏感性越高Septin 9表达越低的趋势,可能作为预测淋巴瘤化疗敏感性的候选标志物。     

High Level of COP1 Expression is Associated with Poor Prognosis in Primary Gastric Cancer

COP1 (constitutive photomorphogenic 1, also known as RFWD2) is a p53-targeting E3 ubiquitin ligase containing RING-finger, coiled-coil, and WD40-repeat domains. Recent studies have identified that COP1 is overexpressed in several cancer types and that increased COP1 expression promotes cell proliferation, cell transformation, and tumor progression. In the present study, we investigated the expression and prognostic value of COP1 in primary gastric cancer. To investigate the role of the COP1 gene in primary gastric cancer pathogenesis, real-time quantitative PCR and western blotting were performed to examine COP1 expression in paired cancerous and matched adjacent noncancerous gastric tissues. The results revealed high COP1 mRNA (P=0.030) and protein (P=0.008) expression in most tumor-bearing tissues compared with the matched adjacent non-tumor tissues. The correlated protein expression analysis revealed a negative correlation between COP1 and p53 in gastric cancer samples (P=0.005, r=-0.572). Immunohistochemical staining of gastric cancer tissues from the same patient showed a high COP1 expression and a low p53 expression. To further investigate the clinicopathological and prognostic roles of COP1 expression, we performed immunohistochemical analysis of 401 paraffin-embedded gastric cancer tissue blocks. The data revealed that high COP1 expression was significantly correlated with T stage (P=0.030), M stage (P=0.048) and TNM stage (P=0.022). Consistent with these results, we found that high expression of COP1 was significantly correlated with poor survival in gastric cancer patients (P<0.001). Cox regression analyses showed that COP1 expression was an independent predictor of overall survival (P<0.001). Our data suggest that COP1 could play an important role in gastric cancer and might serve as a valuable prognostic marker and potential target for gene therapy in the treatment of gastric cancer.     

弥漫大B细胞淋巴瘤1号染色体的基因表达分析

目的:探讨弥漫大B细胞淋巴瘤(Diffuse Large B-Cell Lymphoma,DLBCL)中1号染色体基因表达情况。方法:采用激光显微切割技术分离临床DLBCL病人淋巴结标本中的淋巴细胞,提取淋巴细胞的mRNA并与表达谱芯片杂交,通过信号扫描、处理后获得表达基因杂交信号强度。每基因设11-20对探针。杂交信号与错配探针对比,扣除背景值后,使用Wilcoxon符号秩和检验选取与错配杂交信号有显著差异的基因作为分析结果(P=0.05)。然后随机选取四个检测到的基因,使用PCR方法检验基因芯片结果的可靠性。结果:成功地从快速冷冻保存的DLBCL标本中提取RNA。使用表达谱芯片进行研究,发现了共316条1号染色体编码的基因在DLBCL细胞中表达。根据胞内定位,基因功能和基因所属的代谢通路三种分类方法对所得基因进行分类分析。基因表达密度分析显示DLBCL中1号染色体上的基因表达情况与编码基因分布情况存在统计学差异。结论:使用表达谱芯片研究了DLBCL中1号染色体上的基因表达情况。     

Ectopic Expression of Plk1 Leads to Activation of the Spindle Checkpoint

Polo-like kinase 1 (Plk1), the best characterized member of the mammalian polo-like kinase family, is well regulated throughout the cell cycle, and is inhibited following DNA damage. Chk1 plays a key role in the response to DNA damage. We recently reported that Chk1 is required for mitotic progression through negative regulation of Plk1. Here, we report the phenotypes of cultured cells upon ectopic expression of various forms of Plk1. Epitopic expression of Plk1 led to mitotic arrest, whereas co-expression of Chk1 could release this mitotic block. Moreover, the Plk1 expression-induced mitotic block was also released by inactivation of the spindle-assembly checkpoint.     

VR09 Cell Line: An EBV-Positive Lymphoblastoid Cell Line with In Vivo Characteristics of Diffuse Large B Cell Lymphoma of Activated B-Cell Type

Background

small B-cell neoplasms can show plasmacytic differentiation and may potentially progress to aggressive lymphoma (DLBCL). Epstein-Barr virus (EBV) infection may cause the transformation of malignant cells in vitro.

Design and Method

we established VR09 cell line with plasmacytic differentiation, obtained from a case of atypical, non-CLL B-cell chronic lymphoproliferative disease with plasmacytic features. We used flow cytometry, immunohistochemistry, polymerase chain reaction, cytogenetic analysis and florescence in situ hybridization in the attempt at thoroughly characterizing the cell line. We showed VR09 tumorigenic potential in vivo, leading to the development of activated DLBCL with plasmacytic features.

Results

VR09 cells displayed plasmacytic appearance and grew as spherical tumors when inoculated subcutaneously into immunodeficient Rag2^−/− γ-chain^−/− mice. VR09 cell line and tumors displayed the phenotype of activated stage of B cell maturation, with secretory differentiation (CD19+ CD20+ CD79a+ CD79b+/− CD138+ cyclin D1- Ki67 80% IgM+ IgD+ MUM1+ MNDA+ CD10- CD22+ CD23+ CD43+ K+, λ- Bcl2+ Bcl6-) and they presented episomal EBV genome, chromosome 12 trisomy, lack of c-MYC rearrangement and Myd88 gene mutation, presence of somatic hypermutation in the VH region, and wild-type p53.

Conclusion

This new EBV-positive cell line may be useful to further characterize in vivo activated DLBCL with plasmacytic features.     

The Telomere Repeat Binding Protein Trf1 Interacts with the Spindle Checkpoint Protein Mad1 and Nek2 Mitotic Kinase

The mitotic spindle checkpoint arrests cells in metaphase until all kinetochores arecorrectly attached to spindle fibres. In a search for new components of the spindlecheckpoint, based on protein interaction, we have identified mouse Telomeric RepeatBinding Factor 1 (Trf1) as a protein that interacts directly with the spindle checkpointprotein Mad1 and the mitotic kinase Nek2. Trf1 has a role in the regulation of telomerelength, but has also been implicated in cell cycle regulation. These interactions nowprovide a direct link between telomere length regulation and the control of mitoticprogression.     

The Insulin Receptor Adaptor IRS2 is an APC/C Substrate That Promotes Cell Cycle Protein Expression and a Robust Spindle Assembly Checkpoint

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Highlights

• •Chemical proteomics in G₁ cells treated with small molecule APC/C inhibitors reveals novel putative APC/C substrates.
• •The insulin receptor adaptor IRS2 is an APC/C substrate that is targeted for degradation by APC/C^Cdh1.
• •Quantitative proteomics in IRS2 knockout cells reveals a deficiency in cell cycle related protein expression.
• •IRS2 promotes a robust spindle assembly checkpoint (SAC) during M-phase.

     

Down-Regulation of eIF4GII by miR-520c-3p Represses Diffuse Large B Cell Lymphoma Development

Deregulation of the translational machinery is emerging as a critical contributor to cancer development. The contribution of microRNAs in translational gene control has been established however; the role of microRNAs in disrupting the cap-dependent translation regulation complex has not been previously described. Here, we established that elevated miR-520c-3p represses global translation, cell proliferation and initiates premature senescence in HeLa and DLBCL cells. Moreover, we demonstrate that miR-520c-3p directly targets translation initiation factor, eIF4GII mRNA and negatively regulates eIF4GII protein synthesis. miR-520c-3p overexpression diminishes cells colony formation and reduces tumor growth in a human xenograft mouse model. Consequently, downregulation of eIF4GII by siRNA decreases translation, cell proliferation and ability to form colonies, as well as induces cellular senescence. In vitro and in vivo findings were further validated in patient samples; DLBCL primary cells demonstrated low miR-520c-3p levels with reciprocally up-regulated eIF4GII protein expression. Our results provide evidence that the tumor suppressor effect of miR-520c-3p is mediated through repression of translation while inducing senescence and that eIF4GII is a key effector of this anti-tumor activity.