Reduced expression of heterogeneous nuclear ribonucleoprotein B1 in adult T-cell lymphoma/leukemia

It is considered that hnRNP B1 expresses similarly in the various types of tumor cells. Recently, we demonstrated high B1 expression in B-cell lymphoma and carcinoma. To evaluate the difference of B1 expression between B and T-cell lymphoma, we immunologically studied the B1 expression in 22 cases with nodal T-cell lymphoma, comprising adult T-cell leukemia/lymphoma (ATLL; n=15) and angioimmunoblastic T-cell lymphoma (AILD; n=7), using an anti-hnRNP B1 monoclonal antibody, 2B2. In ATLL cases, scattered large transformed lymphoma cells demonstrated strong B1 expression, while the medium-sized lymphoma cells were negative. On the one hand, lymphoma cells in AILD diffusely expressed B1. The mean B1 expression rate in ATLL was 22%, which was significantly lower than that in AILDs (45%), B-cell lymphomas (44%), and metastatic carcinomas (53%) (p<0.01). Our result might suggest that process of hnRNP B1 expression in ATLL differs from those in other lymphoid neoplasms and carcinoma.     

Heterogeneous nuclear ribonucleoprotein B1 expression in malignant mesothelioma

Heterogeneous nuclear ribonucleoprotein B1, an RNA-binding protein required for mRNA maturation, reportedly is overexpressed in early lung cancer and in several other tumors, including precancerous lesions. Expression of the protein was assessed immunohistochemically in 39 specimens of malignant mesothelioma and five of non-neoplastic pleura, and by flow cytometry in a human epithelioid mesothelioma cell line. No tumor showed overexpression, but 29 of 39 cases showed modest expression. Patients whose tumors showed expression had significantly better survival rates than others. Epithelioid tumors and reactive mesothelial cells were more likely to express the protein than sarcomatoid tumors and resting mesothelial cells. Flow cytometric analysis of an epithelioid mesothelioma cell line demonstrated stronger expression in exponentially growing than growth-restricted cells. Heterogeneous nuclear ribonucleoprotein B1 is expressed widely in malignant mesotheliomas and in reactive mesothelial cells, but is not overexpressed. This protein may regulate proliferation linked with differentiation toward epithelioid morphology in mesothelial cells. Expression of the protein may be a prognostic indicator for patents with malignant mesothelioma.     

痰HnRNP A2/B1表达与肺癌的相关性研究

目的探讨异质性细胞核核糖蛋白A2/B1（heterogeneous nuclear ribonucleoprotein A2/B1,HnRNPA2/B1）的表达水平与肺癌的关系。方法应用免疫组化方法检测非小细胞肺癌患者74例及非肿瘤同期住院患者80例痰液HnRNP A2/B1的表达水平。结果非小细胞肺癌患者痰检阳性率77.0%（57/74）,非肿瘤组阳性率26.3%（21/80）。两组间差异有统计学意义（P〈0.01）。HnRNP A2/B1的过表达与患者吸烟、性别、年龄、肿瘤病理和部位均无相关性。结论HnRNP A2/B1在非小细胞肺癌患者痰液中高表达,痰检HnRNP A2/B1可用于非小细胞肺癌的辅助诊断。     

核内不均一核糖核蛋白 A2/B1在非小细胞肺癌中的表达及其临床意义

目的探讨核内不均一核糖核蛋白 A2/B1(hnRNP A2/B1)在非小细胞肺癌(NSCLC)中的表达特征及其临床意义.方法应用免疫组织化学S-P法检测hnRNP A2/B1在58例NSCLC及癌旁组织、支气管切缘和30例肺良性病变肺组织中的表达,并分析该蛋白表达与肺癌临床病理特征的关系.结果 NSCLC组织中hnRNP A2/B1阳性表达率(63.79%)显著高于癌旁肺组织(43.10%)和肺良性病变肺组织(20.00%)(P＝0.000),癌旁肺组织中hnRNP A2/B1阳性率亦显著高于肺良性病变肺组织(P＜0.05).肺癌患者支气管切缘上皮增生组织阳性表达率(40.00%)显著高于正常支气管上皮(15.15%)(P＝0.032).低分化肺癌hnRNP A2/B1阳性表达率(78.13%)显著高于中-高分化肺癌(46.15%)(P＜0.05),伴有淋巴结转移肺癌阳性表达率(75.00%)显著高于无淋巴结转移肺癌(50.00%)(P＜0.05),Ⅲ+Ⅳ期肺癌阳性表达率(78.57%)显著高于Ⅰ+Ⅱ期(50.00%)(P＜0.05),T3+T4肺癌阳性表达率(77.42%)显著高于T1+T2(48.15%)(P＜0.05).不同组织学类型肺癌组织中hnRNP A2/B1表达水平无显著性差异(P＞0.05).结论 hnRNP A2/B1的异常表达在肺癌的发生、发展和转移中可能发挥着重要作用.检测hnRNP A2/B1对NSCLC的早期诊断和预测预后可能具有重要的临床意义.     

Altered expression and localization of creatine kinase B, heterogeneous nuclear ribonucleoprotein F, and high mobility group box 1 protein in the nuclear matrix associated with colon cancer

Identification of biomarkers could lead to the development of effective screening tests for colorectal cancer. A previous study from our laboratory showed specific alterations of nuclear structure in colon cancer. In an effort to characterize these biomarkers, protein spots were selected from separations made by two-dimensional gel electrophoresis, which were analyzed by mass spectrometry. The sequences obtained from the isolated spots revealed that they have close similarity to creatine kinase B (CKB) isoforms, heterogeneous nuclear ribonucleoprotein F (hnRNP F) and high mobility group box 1 protein (HMGB1) isoforms. To determine the expression of these proteins in colon cancer, expression was studied in 9 tumor and matched adjacent normal pairs, 5 donor colons, 16 polyps, 4 metastatic liver lesions and matched adjacent normal pairs, and 3 liver donors. CKB and hnRNP F were expressed in 78% and 89% of colon tumors, respectively. hnRNP F had a higher frequency of expression than CKB in premalignant polyps. With the establishment of differential expression of the proteins in colon cancer, their subcellular localization was analyzed. The subcellular fractions studied both showed high protein levels of hnRNP F in colon tumors compared with normal colon tissues. Surprisingly, subcellular levels of CKB were decreased in colon tumors, suggesting that the observed high CKB levels in nuclear matrix extracts are caused by the enhanced localization of CKB to the nuclear matrix during colon tumorigenesis. These results suggest an involvement of hnRNP F and CKB in colorectal cancer. Additionally, they suggest that hnRNP F is a potential marker for colorectal cancer progression.     

核不均一核糖核蛋白A2/B1在非小细胞肺癌发病机制中作用的探讨

目的 观察核不均一核糖核蛋白A2/B1(hnRNP A2/B1)在非小细胞肺癌(NSCLC)中的表达及其与DNA修复酶O6-甲基鸟嘌呤-DNA甲基转移酶(MGMT)、8-羟基鸟嘌呤DNA糖苷酶(OGG1)、氧化还原因子1(Ref-1)、DNA依赖性蛋白激酶复合物DNA-PKcs和Ku mRNA之间的相互作用,并进一步探讨其在NSCLC发病机制中的作用.方法 采用免疫组化、Western blot及荧光实时定量PCR方法,检测NSCLC患者癌组织及正常肺组织hnRNP A2/B1的表达.采用免疫共沉淀结合逆转录聚合酶链反应(RT-PCR)方法,研究人肺鳞癌细胞株中hnRNP A2/B1蛋白是否与上述5种DNA修复酶的mRNA直接结合,然后采用免疫组化及荧光实时定量PCR方法,检测NSCLC患者癌组织及正常肺组织MGMT的表达情况.结果 免疫组化染色显示,hnRNP A2/B1定位于细胞核,hnRNPA2/B1在NSCLC癌组织中的表达阳性率(100%)和蛋白表达评分[(5.3±0.9)分]均显著高于正常肺组织[32%和(2.2±0.7)分,P＜0.01],在Ⅲ～Ⅳ期NSCLC组织中的表达略高于Ⅰ～Ⅱ期(P＜0.05),而与年龄、性别、组织学类型及吸烟状况无关(均P＞0.05).通过RT-PCR方法可以从人肺鳞癌细胞株免疫共沉淀产物中扩增出MGMT mRNA,提示hnRNP A2/B1与MGMT mRNA相结合.进一步的免疫组化染色结果显示,在NSCLC组织中,MGMT的表达阳性率为32.0%,明显低于正常肺组织(78.0%),蛋白表达评分[(2.2±0.8)分]也显著低于正常肺组织[(4.1±1.2)分,P＜0.01].荧光实时定量PCR结果显示,NSCLC组织中MGMT mRNA的表达量为1.8(0.6～3.1),明显低于正常肺组织[9.8(6.8～18.3),P＜0.01].结论 HnRNP A2/B1蛋白及mRNA在NSCLC组织中的表达均升高,hnRNP A2/B1与MGMT mRNA相结合,可能通过对MGMT mRNA的转录后调控参与NSCLC的发生.

Abstract：

Objective To study the expression of heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) in non-small cell lung cancer(NSCLC),and the interaction between hnRNP A2/B1 protein and mRNA of DNA repair enzymes O6-methylguanine DNA-methyltransferase(MGMT),8-oxoguanine DNA glycosylase(OGG1),redox factor 1(Ref-1),DNA-dependent protein kinase(including DNA-PKcs and ku). Methods The expression and distribution of hnRNP A2/B1 were detected by immunohistochemistry and Western blot on 50 NSCLC samples from patients who underwent resection in Zhongshan Hospital.The hnRNP A2/B1 mRNA expression was tested by real-time PCR.Coimmunoprecipitation(co-IP) combined RT-PCR was used to investigate whether hnRNP A2/B1 could be bound with the mRNA of the above mentioned 5 DNA repair enzymes in human lung cancer cell line(HTB-182).Then immunohistochemistry and real-time PCR were used to detect the expression of MGMT in the same group of patients. Results HnRNP A2/B1 protein and mRNA expressions were increased in the NSCLC tissues than that in the corresponding normal lung tissues.HnRNP A2/B1 was expressed predominantly in the nuclei of tumor cells.The positive rate and immunohistochemistry score of hnRNP A2/B1 in tumor tissue were significantly higher than that in normal tissue(P ＜0.01).In stage Ⅲ-Ⅳ NSCLC,hnRNP A2/B1 expression was higher than that in stage Ⅰ-Ⅱ.There was no significant differences of hnRNP A2/B1 expression among patients of different age,sex,histological type,and smoking history.The results of co-IP combined RT-PCR suggested that hnRNP A2/B1 is bound with MGMT mRNA,and MGMT expression is decreased in tumor tissue of NSCLC. Conclusions The results of this study show that hnRNP A2/B1 protein and mRNA are highly expressed in NSCLC,and hnRNP A2/B1 is bound with MGMT mRNA,which indicate that it might be one of the mechanisms of hnRNP A2/B1 participating in the pathogenesis of NSCLC.     

Spontaneous follicular center cell lymphomas of B cell origin in cataract mice.

Spontaneous lymphomas from a strain of hereditary cataract (CAC-nct/+) mice were examined by light and electron microscopy and by immunohistochemical reaction for the mouse heavy and light immunoglobulin chains. Lymphomas occurred in 28 out of 45 male cataract mice and in 34 out of 52 females at 25 to 65 weeks of age. All of the lymphoma-bearing mice showed an enlargement of the spleen and mesenteric lymph nodes, and some mice also had hepatomegaly. Morphologically, all tumors were composed of a mixed population of small and large cells. Neoplastic cells had features of follicular center cell lymphomas, such as scant to moderate amounts of cytoplasm and cleaved and/or round nuclei with a large nuclear-to-cytoplasmic ratio. Large cells were often admixed with small cells, and had vesicular nuclei with prominent nucleoli juxtaposed to the nuclear membrane. Intracytoplasmic eosinophilic inclusions were observed in occasional cells, but Golgi apparatus was poorly developed and rough-surfaced endoplasmic reticulum was scant, unlike those in plasma cells. C-particles were seen in all lymphoma-bearing mice by electron microscopy. Intracisternal A-particles were detected in some mice. Immunohistochemically, neoplastic lymphoid cells were positive for the kappa light chain and the surface/cytoplasmic immunoglobulin M. These results indicate that lymphoid cell neoplasms found in hereditary cataract mice originate from follicular center B cells.     

Significance of heterogeneous nuclear ribonucleoprotein B1 as a new early detection marker for oral squamous cell carcinoma.

The development of an early tumor detection marker for oral cancer is an obvious need due to the high recurrence rate and poor survival rate. Based on our previous report that overexpression of heterogeneous nuclear ribonucleoprotein (hnRNP) B1 protein was found in 100% of squamous cell carcinomas of human lung, we applied the same immunohistochemical method, using anti-hnRNP B1 antibody, to human oral squamous cell carcinoma (OSCC). Seven human tissue sections of OSCC showed strong staining with anti-hnRNP B1 antibody, and hnRNP B1 protein of 37 kDa was identified in protein fractions isolated from six of the cancerous tissue sections, while it was not found in adjacent noncancerous tissue. Moreover, three non-homogeneous (nodular) leukoplakia sections showed significant anti-hnRNP B1 staining. The results suggest that this antibody detects precancerous lesions as well as advanced lesions (stages I to IV) of OSCC. We also present positive results of cytodiagnosis for two smear specimens. All of the above results indicate that hnRNP B1 is a new and useful marker for early detection of OSCC.     

The expression of PRAME in chronic lymphoproliferative disorders

The PRAME gene encodes an antigen recognized by autologous T lymphocytes and is expressed in trophoblasts, testis and frequently in human solid cancers and acute leukemias, making it a candidate for immunotherapy and for detecting MRD. We demonstrate expression of PRAME by RT-PCR in the peripheral blood or bone marrow of 26% of 58 patients with CLD (38 cases of CLL, 4 cases of PLL and 16 cases of NHL). Seven out 16 cases of MCL, 2 out 4 of PLL and 6 cases of CLL demonstrated some degree of gene expression. Thus, CLD are among the hematopoietic malignancies for which PRAME may be the target of immunological therapy or used to evaluate MRD. The stronger and more frequent expression of PRAME in MCL is apparently an additional distinguishing feature on this group of lymphoproliferative disorders.     

Expression and mutation analysis of heterogeneous nuclear ribonucleoprotein G in human oral cancer

We previously reported that wild type (wt) hnRNP G exhibited tumor suppressive activity in human oral squamous cell carcinoma (HOSCC) cell lines lacking hnRNP G. Wt hnRNP G markedly inhibited the proliferation capacity, anchorage independency and in vivo tumorigenicity of HOSCC cells and notably enhanced the DNA repair capabilities of these cells. In the present study, we studied the genetic and expression states of hnRNP G in normal, premalignant and malignant human oral tissues to further understand the relationship between the hnRNP G alterations and the development of human oral cancer. To correlate the cancer development and the level of hnRNP G expression, we performed an immunohistochemistry staining of hnRNP G in normal, premalignant and malignant human oral tissues. Moreover, we examined the entire coding regions of hnRNP G from selected samples to understand the cause of the alterations of the gene expression.The expression of hnRNP G was notably decreased or completely abolished in 80% of premalignant-dysplastic and malignant oral epithelial tissues, whereas 100% of normal and 90% of hyperplastic non-dysplastic epithelium showed high level of hnRNP G in the nucleus of the basal cell layers. Approximately 80% of HOSCC lacking the expression of hnRNP G showed genetic alteration in hnRNP G, i.e., point mutation and exonic deletion. This study suggest that genetic alterations and aberrant expression of hnRNP G occurring during oral carcinogenesis might be useful markers for the early detection of human oral cancer.     

Emerging roles of heterogeneous nuclear ribonucleoprotein K (hnRNP K) in cancer progression

The heterogeneous nuclear ribonucleoprotein K (hnRNP K) is a nucleic acid-binding protein that serves as a docking platform integrating transduction pathways to nucleic acid -directed processes. Recently, this protein has emerged as an important player in carcinogenesis process. HnRNP K is overexpressed in several human cancers and its aberrant cytoplasmic localization has been associated with a worse prognosis for patients, suggesting that it has a role in cancer progression. Herein, we provide a brief overview of the multifunctional roles of hnRNP K and discuss clinical studies that have demonstrated its involvement in cancer development and progression.