The Synovial Sarcoma-Associated SYT-SSX2 Oncogene Antagonizes the Polycomb Complex Protein Bmi1

This study demonstrates deregulation of polycomb activity by the synovial sarcoma-associated SYT-SSX2 oncogene, also known as SS18-SSX2. Synovial sarcoma is a soft tissue cancer associated with a recurrent t(X:18) translocation event that generates one of two fusion proteins, SYT-SSX1 or SYT-SSX2. The role of the translocation products in this disease is poorly understood. We present evidence that the SYT-SSX2 fusion protein interacts with the polycomb repressive complex and modulates its gene silencing activity. SYT-SSX2 causes destabilization of the polycomb subunit Bmi1, resulting in impairment of polycomb-associated histone H2A ubiquitination and reactivation of polycomb target genes. Silencing by polycomb complexes plays a vital role in numerous physiological processes. In recent years, numerous reports have implicated gain of polycomb silencing function in several cancers. This study provides evidence that, in the appropriate context, expression of the SYT-SSX2 oncogene leads to loss of polycomb function. It challenges the notion that cancer is solely associated with an increase in polycomb function and suggests that any imbalance in polycomb activity could drive the cell toward oncogenesis. These findings provide a mechanism by which the SYT-SSX2 chimera may contribute to synovial sarcoma pathogenesis.     

Establishment and characterization of a clonal human extraskeletal Ewing's sarcoma cell line, EES1

Ewing's sarcoma, a small round cell sarcoma arising in soft tissue as well as the bone, is one of the most malignant tumors in children and young adults. Few established cell lines of extraskeletal Ewing's sarcoma (EES) have been reported, which made it difficult to examine the biological features of EES. Therefore, we have established a new clonal cell line of EES. We report its morphological characters, results of chromosomal and immunohistochemical analysis. A piece of tumor obtained from the 18-year-old female patient with EES was xenografted in a nude mouse. In vitro subcultured cells were then obtained from this xenograft. A clonal cell line was subsequently established by limiting dilution and designated EES1. EES1 cells had a doubling time of 24 hours. In the xenografted tumor, the cells expressed vimentin, CD99 (MIC2), neuron specific enolase (NSE) and cytokeratin. The original tumor cells also expressed vimentin, CD 99, and NSE, but was negative for cytokeratin. The morphological and immunohistochemical features of this cell line established, except for cytokeratin expression, were consistent with those of the primary tumor. Cytogenetic analysis of EES1 revealed chromosomal translocation of t(11; 12)(q24;ql2). The chimeric fusion of the Ewing's sarcoma gene in band 22q12 with the Friend leukemia virus integration-1 gene in band 11q24 was also demonstrated. Fluorescence in situ hybridization further confirmed the presence of translocation involving the Ewing's sarcoma gene in both the primary tumor and EES1 cells. In conclusion, we have established a human EES cell line EES1, which will provide a useful model for studying various aspects of human EES.     

一种新的早幼粒细胞白血病/维甲酸受体α融合基因S亚型变异易位

目的：逆转录聚合酶链反应（RT－PCR）检测早幼粒细胞白血病／维甲酸受体α（PML／RARα）融合基因，筛查变异易位并对变异易位产物测序，以进一步了解变异易位的特点及临床意义。方法：取急性早幼粒细胞白血病（APL）患者骨髓，RT－PCR检测L亚型和S亚型，发现的变异易位经全自动测序仪测定其碱基序列。结果：11例PML／RARα融合基因表达的患者中，S亚型1例、L亚型8例、变异S亚型合并L亚型2例；变异S亚型产物测序得到206bp的碱基序列，检索证实是一种新的变异易位。结论：发现了一种新的S亚型变异易位，证实同一个体可有S和L二种不同亚型并存；提示PML／RARα融合基因的RT－PCR检测中，识别变异易位有重要意义。     

前列腺癌组织中TMPRSS2基因与ETS家族基因的多种融合亚型及意义

目的：了解前列腺癌组织标本中跨膜丝氨酸蛋白酶2（TMPRSS2）基因与ETS转录因子家族成员ETS相关基因（ERG）、ETS变异体1（ETV1）及ETS变异体4（ETV4）基因之间的融合情况及意义。方法：采用巢式逆转录聚合酶链反应（RT—PCR）琼脂糖凝胶电泳法，检测32例前列腺癌患者及34例前列腺良性增生患者，前列腺组织中TMPRSS2基因与ETS家族基因融合的TMPRSS2／ERG、TMPRSS2／ETV1、TMPRSS2／ETV4转录体；琼脂糖凝胶电泳阳性者，纯化PCR产物进行直接测序，用BLAST在线软件比对确定融合位点；分析融合基因与Gleason分级关系。结果：在32例前列腺癌患者组织标本中，检测到TMPRSS2／ERG融合基因17例（53．1％），含5种不同融合基因亚型，其中1种为新发现融合基因亚型（Genbank登录号：EU090248），单一标本中可检测到一种以上TMPRSS2／ERG融合基因亚型；检测到TMPRSS2／ETV1融合基因2例（6．3％），为新发现融合基因亚型（Genbank登录号：EU090249）；未检到TMPRSS2／ETV4融合基因型；34例前列腺良性增生组织标本中均未检测到TMPRSS2／ERG、TMPRSS2／ETV1和TMPRSS2／ETV4融合基因型；按Gleason评分值分为中分化与低分化的两组前列腺癌组织标本之间融合基因阳性率无统计学差异（P=0．169）。结论：前列腺癌组织中存在TMPRSS2／ERG和TMPRSS2／ETV1融合基因及多种亚型；前列腺癌融合基因的发现有望为前列腺癌的发病机制研究提供新的思路。     

多发性骨髓瘤患者IgH-MMSET基因的检测及其意义

目的：检测多发性骨髓瘤(MM)患由于t(4；14)所形成的IgH-MMSET融合基因，探讨其在MM中的临床意义。方法：采用RT-PER法在25例MM患骨髓标本和MM细胞系NCI-H929中检测IgH-MMSET融合基因，并且通过巢式PCR法提高反应的灵敏度。PCR产物纯化后克隆到pGEM-T载体，并用引物M13 Forward测序。将PCR产物的序列与GenBank进行对照，进一步证实发生易位的基因。结果：作为阳性对照的MM细胞系NCI-H929扩增出一明显条带，长度为438bp，经测序后证实为IgH基因与MMSET基因的融合产物。14号染色体及4号染色体上的断裂点分别位于IgH基因的Cμ区及MMSET基因的第3内含子中。25例MM患的骨髓标本扩增后有3例(12．O％)呈现阳性，经分别测序后证实为IgH-MMSET融合基因，扩增产物的长度分别为237bp、239bp和239bp，三第4染色体的断裂方式均与NCI-H929相同，其中l例缺失了MMSET基因的第4外显子的第74位碱基(A)和第75位碱基(T)。结论：MM患IgH-MMSET融合基因是由于t(4；14)所形成，其发生率为12．O％。IgH-MMSET融合基因的出现可能是MM患预后不良的指标之一。     

Delving deeper into MALT lymphoma biology

Mucosa-associated lymphoid tissue (MALT) lymphomas can arise in a variety of extranodal sites. Interestingly, at least 3 different, apparently site-specific, chromosomal translocations, all affecting the NF-kappaB pathway, have been implicated in the development and progression of MALT lymphoma. The most common is the translocation t(11;18)(q21;q21), which results in a fusion of the cIAP2 region on chromosome 11q21 with the MALT1 gene on chromosome 18q21 and is present in more than one-third of cases. The frequency of this translocation is site-related: common in the gastrointestinal tract and lung, rare in conjunctiva and orbit, and almost absent in salivary glands, thyroid, liver, and skin. In this issue of the JCI, Hu et al. add to our understanding of the molecular consequences of this translocation, showing that its fusion product, cIAP2-MALT1, may concomitantly contribute to lymphomagenesis both as a tumor suppressor gene and as an oncogene.     

两例急性髓系白血病伴t(6;21;8)(p22;q22;q22)复杂易位患者的临床与实验室研究

目的探讨2例急性髓系白血病（AML）伴t（6;21;8）（p22;q22;q22）复杂易位患者的临床及实验室特点.方法骨髓细胞经短期24 h培养后按常规方法制备染色体标本,R显带进行核型分析;双色双融合AML1/ETO探针进行丝裂间期及中期荧光原位杂交（FISH）检测AML1/ETO融合信号;逆转录-聚合酶链反应（RT-PCR）检测AML1/ETO融合基因转录本;综合分析临床特征.结果2例患者常规细胞遗传学分析显示均存在t（6;21;8）（p22;q22;q22）,间期和中期FISH证实了核型结果;RT-PCR检测到AML1/ETO融合基因转录本;尽管2例患者均诊断为AML-M2,但二者的免疫表型和治疗反应不同.结论t（6;21;8）（p22;q22;q22）是一种少见的t（8;21）（q22;q22）的复杂变异易位,还需要更多的病例以明确其临床特征和预后价值.     

Quantification of bcl-2/JH fusion sequences and a control gene by multiplex real-time PCR coupled with automated amplicon sizing by capillary electrophoresis

Follicular lymphoma is characterized by the presence of the t(14;18)(q32;q21) chromosomal translocation which juxtaposes the bcl-2 gene at 18q21 with the immunoglobulin heavy chain locus at 14q32. Quantification of t(14;18) carrying cells in FL patients can be achieved by real-time PCR, a highly sensitive technique for evaluating treatment efficacy and minimal residual disease. Despite the many advantages of real-time technology for this purpose, one disadvantage is that current real-time t(14;18) PCR assays amplify a control gene as a normalizer in a separate reaction. Since each PCR reaction has its own kinetics, separate PCR assays for target and control sequences can potentially result in inaccurate quantification of t(14;18)-positive cells. In addition, the real-time t(14;18) PCR assays do not determine the size of the amplified fusion sequence, which is helpful for excluding contamination and is commonly used to demonstrate clonal identity between pre- and post-treatment specimens from a patient. To address these limitations, we designed a multiplex real-time PCR protocol that allows amplification of control and target genes in the same reaction and precise size determination of bcl-2/JH fusion sequences by capillary electrophoresis. This multiplex PCR assay is equally sensitive to previous assays, allows more accurate quantification of bcl-2/JH fusion sequences, and is more convenient.     

Usefulness of long‐distance inverse polymerase chain reaction for molecular detection of 14q32 translocation in a clinical setting

All mature B‐cell leukaemias and lymphomas have a clonal Ig gene recombination, and half of them have a reciprocal chromosomal translocation involving the 14q32 locus. The 14q32 translocation partners are variable, such as BCL‐2, BCL‐1 and BCL‐6, thus accounting for the difficulty in molecular detection by the current genomic polymerase chain reaction (PCR) method. To identify B‐cell clones efficiently with an Ig gene rearrangement and reciprocal inter‐chromosomal translocation, we verified the usefulness, in a practical laboratory setting, of our modified long‐distance inverse (LDI) PCR method for detecting IgH gene rearrangements involving inter‐ and intra‐chromosomal segments. The total run time of this LDI PCR method was 5.5?h. Using 24 samples of mature B‐cell leukaemias and lymphomas, the modified LDI PCR gave clonally rearranged amplicons in 83?% (20/24) of cases. Direct sequencing results of the amplicons revealed inter‐chromosomal translocations in 5 cases (25?%) and intra‐chromosomal rearrangements in the remaining 15 cases (75?%). The partners of the inter‐chromosomal translocation consisted of the 11q13.3 segment containing a partial BCL1 sequence in 3 cases; 18q21.3 segment containing a partial BCL2 sequence in one case; and a segment of 7q11.2 in one case. We present an LDI PCR‐based methodology for the efficient identification of 14q32 translocations, with modifications to reduce the total run time to within one day.     

Genotype-specific signal generation based on digestion of 3-way DNA junctions: application to KRAS variation detection

BACKGROUND: Genotyping methods that reveal single-nucleotide differences are useful for a wide range of applications. We used digestion of 3-way DNA junctions in a novel technology, OneCutEventAmplificatioN (OCEAN) that allows sequence-specific signal generation and amplification. We combined OCEAN with peptide-nucleic-acid (PNA)-based variant enrichment to detect and simultaneously genotype v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) codon 12 sequence variants in human tissue specimens. Materials and METHODS: We analyzed KRAS codon 12 sequence variants in 106 lung cancer surgical specimens. We conducted a PNA-PCR reaction that suppresses wild-type KRAS amplification and genotyped the product with a set of OCEAN reactions carried out in fluorescence microplate format. The isothermal OCEAN assay enabled a 3-way DNA junction to form between the specific target nucleic acid, a fluorescently labeled "amplifier", and an "anchor". The amplifier-anchor contact contains the recognition site for a restriction enzyme. Digestion produces a cleaved amplifier and generation of a fluorescent signal. The cleaved amplifier dissociates from the 3-way DNA junction, allowing a new amplifier to bind and propagate the reaction. RESULTS: The system detected and genotyped KRAS sequence variants down to approximately 0.3% variant-to-wild-type alleles. PNA-PCR/OCEAN had a concordance rate with PNA-PCR/sequencing of 93% to 98%, depending on the exact implementation. Concordance rate with restriction endonuclease-mediated selective-PCR/sequencing was 89%. CONCLUSION: OCEAN is a practical and low-cost novel technology for sequence-specific signal generation. Reliable analysis of KRAS sequence alterations in human specimens circumvents the requirement for sequencing. Application is expected in genotyping KRAS codon 12 sequence variants in surgical specimens or in bodily fluids, as well as single-base variations and sequence alterations in other genes.     

婴儿急性白血病的临床的分子生物学特点

目的 对２岁以下的婴儿急性白血病作临床和分子生物学特点的研究。方法 用Ｒ带和（或）Ｇ带分带技术进行核型分析，ＤＮＡ印迹法检测ＨＲＸ重排，聚合酶链瓜作逆转录－聚合酶链反应进行融合基因检测。结果 ２０例患经检测后其中１０例有ＨＲＸ基因重排，该１０例作融合基因的检测，５例是ＡＦ－４／ＨＲＸ，２例是ＡＦ－９／ＨＲＸ，１例是ＨＲＸ／ＥＮＬ，１例是ＨＲＸ自我融合，１例是未曾报告过的命名为ＨＲＸ／ＥＥＮ的融合     

一株伴有t(6;11)(q27;q23)和p53基因异常的人单核细胞白血病细胞系SHI-1的建立及鉴定

目的建立人急性单核细胞白血病(AML—M5b)细胞系并研究其生物学特性。方法从1例AML—M5b患者白血病复发时的骨髓标本分离出单个核细胞，用液体培养法进行培养。采用瑞特染色、电子显微镜、细胞化学染色、流式细胞仪、R显带核型分析、逆转录-聚合酶链反应(RT—PCR)、荧光原位杂交(FISH)、半固体甲基纤维素集落培养、裸小鼠致瘤实验、荧光定量PCR、DNA荧光染色法及支原体肉汤培养法、短串联重复序列(STR)-PCR、p53基因的PCR扩增产物测序、多色FISH(M—FISH)和^3H—TdR掺入实验等方法对SHI-1细胞的生物学特性进行了鉴定、结果建立了1个可持续增殖的人单核细胞白血病细胞系SHI-1；形态学和免疫表型呈现典型的单核系特征；核型分析显示SHI-1细胞系有和患者复发时骨髓细胞完全相同的异常：46，XY，t(6；11)(q27；q23)，del(17)(p11)；RT—PCR检出MLL—AF6融合基因的转录本；FISH俭测结果显示存在6号和11号染色体之间易位、MLL基因的重排和p53基因的缺失；PCR产物测序结果显示1个p53等位基因6号外显子发生点突变ATC→ACC集落培养显示SHI-1细胞具有较强的集落形成能力；皮下接种4只裸小鼠均形成实体肿瘤；荧光定量PCR提示无EB病毒感染；DNA荧光染色法和支原体肉汤培养法术检出支原体；M—FISH证实传代至2003年3月的SHI-1细胞除有t(6；11)、del(17)(p11)外，还有t(7；13)所致的衍生7号染色体、18单体和来自8号染色体的微小体；STR—PCR结果显示SHI-1细胞系确实来自患者原代白血病细胞；IL4-和IL-15可促进SHI-1细胞的增殖，IFN-1、TNFα、IL-2、PDGF和IL-7可抑制SHI-1细胞的增殖。结论SHI-1是1个伴有t(6；11)(q27；q23)和P53基因异常的裸小鼠高致瘤性人单核细胞白血病细胞系，为白血病研究提供了一个新的有价值的工具。     

Histone deacetylase inhibitors induce growth arrest, apoptosis, and differentiation in clear cell sarcoma models

Clear cell sarcoma is an aggressive malignancy occurring most commonly in the distal extremities of young adults, characterized by t(12;22)(q13;q12) creating the chimeric fusion oncoprotein EWS-ATF1. We assessed growth inhibition and differentiation effects of histone deacetylase inhibitors MS-275 and romidepsin (depsipeptide, FK228) on clear cell sarcoma cells and evaluated drug sensitivity among related translocation-associated sarcomas and other cell models. Three clear cell sarcoma cell lines, seven other sarcomas, six nonsarcoma malignant cell lines, and two nonneoplastic mesenchymal cell models were treated with MS-275 or romidepsin. Growth inhibition was assayed by monolayer 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Induction of cell cycle arrest and apoptosis were assessed by propidium iodide/Annexin V flow cytometry in monolayer and spheroid cultures and by immunoblotting analysis. Expression levels of key genes involved in mesenchymal differentiation and of EWS-ATF1 were measured by quantitative real-time PCR in clear cell sarcoma cells treated with histone deacetylase inhibitors. MS-275 and romidepsin inhibited growth in clear cell sarcoma cells by inducing cell cycle arrest and apoptosis in a time- and dose-dependent manner. Sarcomas showed greater sensitivity than other tumor types, with clear cell sarcomas most sensitive of all, whereas nonmalignant mesenchymal cells were highly resistant. MS-275 at 1 micromol/L and romidepsin at 1 nmol/L induced histone H3 acetylation, cell cycle arrest, apoptosis, and differentiation in clear cell sarcoma cells within 24 hours. Histone deacetylase inhibitors increased expression of SOX9, MYOD1, and PPARG and decreased EWS-ATF1 expression in clear cell sarcoma cells. Histone deacetylase inhibitors show promising preclinical activity in multiple clear cell sarcoma models.