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.     

Extraskeletal and skeletal myxoid chondrosarcoma: A multiparameter analysis of three cases including cytogenetic analysis and fluorescence in situ hybridization

Background: Myxoid chondrosarcoma (MCS) is a rare, low-grade, indolent tumor that can occur in soft tissue and bone. It is, however, capable of distant metastases. Previous cytogenetic data include a translocation, t(9;22)(q22-31;q12), occurring in 6 of 14 cases of the extraskeletal variant of the disease. Recently, rearrangement of the EWS gene has been reported in MCS.Methods and Results: Three cases of MCS, two skeletal and one extraskeletal, were examined to identify primary cytogenetic changes and correlate these with immunohistochemical, ultrastructural, and flow-cytometric analysis. The extraskeletal variant of MCS revealed a clonal translocation, t(9;22)(q22;q12), and trisomy for chromosomes 5, 7, 8, 12, 18, and 19. Our two cases of skeletal MCS showed complex karyotypes. In one skeletal tumor, a cryptic translocation involving chromosome 6p21.3 was identified by fluorescence in situ hybridization analysis, using chromosome-specific libraries.Conclusions: Thus far, 50% of cases of extraskeletal MCS, including our cases, have demonstrated a specific translocation, t(9;22)(q22-31;q12). Identifying this translocation is useful in confirming the diagnosis of MCS. Additional cytogenetic and molecular analysis is useful for detecting this translocation, and is also essential to determine other regions of possible diagnostic importance, such as the 6p21.3 breakpoint demonstrated in the present study. These techniques may be most useful for the skeletal lesions, in light of their heterogeneous cell populations and karyotypic variability. (Mol Diagn 1996 Jun;1(2):99-107)     

Interphase cytogenetics for the detection of the t(11;22)(q24;q12) in small round cell tumors.

Among the small round cell tumors differential diagnosis is particularly difficult for their undifferentiated or primitive character. In this mixed group of tumors, only the primitive neuroectodermal tumors, which include Ewing's sarcoma (ES), show the unique and consistent feature of the (11;22)(q24;q12) translocation, which can therefore be considered a hallmark of these neoplasias. We analyzed four primitive neuroectodermal tumor cell lines, one osteosarcoma cell line, and 11 patients by fluorescent in situ hybridization with cosmid clones 23.2 and 5.8, bracketing the t(11;22) at 11q24. Metaphase spreads from tumor cell lines, and from biopsy specimens of three patients with ES were analyzed. In the remaining eight patients comprising five ES, two small cell osteosarcomas and one chronic osteomyelitis, only nuclei preparations were available for analysis. We detected the t(11;22) in interphase nuclei of the four primitive neuroectodermal tumor cell lines, of three patients in which the karyotype demonstrated the translocation and in five cases of ES in which cytogenetic analysis had not been possible. Two cases of small cell osteosarcoma and one chronic osteomyelitis were also analyzed and were both normal with respect to the t(11;22). By analyzing cell lines and small round cell tumor samples by fluorescent in situ hybridization, we established that interphase cytogenetics is a rapid alternative to chromosomal analysis for the detection of the t(11;22) and represents an invaluable tool for the differential diagnosis of small round cell tumors.     

Evidence by spectral karyotyping that 8q11.2 is nonrandomly involved in lipoblastoma

We report two cases of lipoblastoma with chromosome 8-related aberrations, ie, a 92,XXYY,t(7;8)(p22;q11.2)x2 [8]/46,XY[16] in Case 1 and a 46,XY,−8,−13,add(16)(q22),+mar, +r [cp13]/46,XY[7] in Case 2. Using spectral karyotyping and fluorescence in situ hybridization techniques, the karyotype of Case 2 was redesignated as 46,XY, r(8), del(13)(q12), der(16)ins(16;8)(q22;q24q11.2)[cp13]/46,XY[7]. This report delineates a new chromosome rearrangement, ie, der(16)ins(16;8)(q22;q24q11.2) in lipoblastoma, and also confirms the t(7;8)(p22;q11.2), reported only once previously, as a recurrent translocation involved in such a tumor. These findings provide valuable information for clinical molecular cytogenetic diagnosis of lipoblastoma. Furthermore, this report highlights the value of cytogenetic and molecular cytogenetic analysis in differential diagnosis of childhood adipose tissue tumors and adds to the number of lipoblastomas reported with chromosomal abnormalities at 8q11.2.     

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。     

Fluorescence in situ hybridization analysis of immunoglobulin heavy chain translocations in plasma cell myeloma using intact paraffin sections and simultaneous CD138 immunofluorescence

Fluorescence in situ hybridization (FISH) studies are much more sensitive than classical cytogenetics for identification of karyotypic abnormalities in plasma cell myeloma. However, FISH analysis of bone marrow samples is often challenging because of a large number of admixed non-neoplastic hematopoietic elements. In this report, we describe a novel method using FISH analysis of intact paraffin sections of formalin-fixed, bone marrow clot preparations with simultaneous CD138 tyramine signal amplification (TSA)-mediated immunofluorescence. We studied 22 cases of plasma cell myeloma for translocations involving the immunoglobulin heavy chain locus that are of known diagnostic and/or prognostic significance. All cases were analyzed using dual color, break-apart immunoglobulin heavy chain probe and dual color, dual fusion probes for t(11;14)(q13;q32) and t(4;14)(p16;q32). TSA-mediated fluorochrome deposition in CD138+ cells was unaltered by protease pretreatment. Translocations were identified in 10 cases, including five with t(11;14)(q13;q32) and three with t(4;14)(p16.3;q32). When present, abnormalities were identified in a large percentage of CD138+ cells (47 to 93%, median 84%). This technique allows for efficient molecular cytogenetic analysis of plasma cell myeloma using routinely archived paraffin-embedded material.     

Overexpression of PRAD1 gene in B-cell malignancy with t(11;14)(q13;q32) translocation]

PRAD1 (parathyroid adenoma 1) gene at chromosome 11q13 has been cloned from parathyroid adenomas as a putative oncogene, activated by translocation with the parathyroid hormone gene. 4.5 kb and 1.7 kb mRNA are transcribed and both have the same open reading frame of 885 bp encoding 34 kd protein of a cyclin gene family, cyclin D1. Recently, overexpression of PRAD1 gene has been reported to be correlated closely with the rearrangement of bcl-1 locus, particularly in centrocytic lymphoma. In our study, overexpression of PRAD1 gene was shown in five B cell lines with t(11;14)(q13;q32) including one centrocytic lymphoma line and 4 myeloma lines, when compared with other hematopoietic cell lines without translocation. One of the cell lines, SP-49, demonstrated a truncated mRNA of 3.4 kb, in addition to 1.7 kb of normal size. Southern blot analysis demonstrated a rearrangement with PRAD1 cDNA probe, suggesting that the gene is altered in this particular cell line. By cloning analysis, we confirmed that 1.8 kb deletion in 3' region of PRAD1 gene eliminating the destabilizing signal of PRAD1 mRNA, gave rise to the aberrant mRNA of 3.4 kb. These findings suggest that PRAD1 gene is most likely the candidate oncogene for bcl-1 activated by t(11; 14)(q13;q32) translocation. The gene alteration found in one cell line, SP-49, might also play an important role for deregulation of the gene.     

EWS-Fli1 antisense oligodeoxynucleotide inhibits proliferation of human Ewing's sarcoma and primitive neuroectodermal tumor cells.

The translocation t(11;22) is a common chromosomal abnormality detected both in Ewing's sarcoma and in primitive neuroectodermal tumor cells. The translocation results in an EWS-Fli1 fusion gene, made up of the 5' half of the EWS gene on chromosome 22 fused to the 3' half of the Fli1 gene on chromosome 11. Recent studies have evaluated possible roles of the fusion gene products. However, the biological significance of EWS-Fli1 is still unknown. Using a competitive polymerase chain reaction technique, we show here that there might be a correlation between the expression levels of the EWS-Fli1 fusion gene and the proliferative activities of Ewing's sarcoma and primitive neuroectodermal tumor cells. When the EWS-Fli1 expression is inhibited by antisense oligodeoxynucleotides against the fusion RNA, the growth of the tumor cells is significantly reduced both in vitro and in vivo. The data further indicate the growth inhibition of the cells by the antisense sequence might be mediated by G0/G1 block in the cell cycle progression. These results suggest that EWS-Fli1 may play an important role in the proliferation of the tumor cells, and the EWS-Fli1 fusion RNA could be used as a target to inhibit the growth of Ewing's sarcoma and primitive neuroectodermal tumor with the specific antisense oligonucleotide.     

二例伴有t(3;5)(q25;q34)的骨髓增生异常综合征的临床和实验研究

目的：报道2例伴有t(3；5）（q25；q34）的骨髓增生异常综合征（MDS）。方法：骨髓细胞24h培养后按常规方法制备染色体，用R显带技术进行细胞遗传学分析，并以3号和5号染色体涂染探针进行荧光原位杂交（FISH）检测。结果：2例的临床和血液学改变符合MDS诊断，染色体核型分析揭示2例患者均有一致的核型异常：46，XY，t(3；5）（q25；q34）；其中1例患者的双色FISH检测证实1条3号染色体长臂和1条5号染色体长臂之间发生了相互易位。结论：t(3；5）（q25；q34）是一种少见的核型异常，它和MD有特别的联系，常有涉及三系的病态造血改变；染色体涂染技术是检测该易位的可靠手段。     

CD99 inhibits neural differentiation of human Ewing sarcoma cells and thereby contributes to oncogenesis

Ewing sarcoma (EWS) is an aggressive bone tumor of uncertain cellular origin. CD99 is a membrane protein that is expressed in most cases of EWS, although its function in the disease is unknown. Here we have shown that endogenous CD99 expression modulates EWS tumor differentiation and malignancy. We determined that knocking down CD99 expression in human EWS cell lines reduced their ability to form tumors and bone metastases when xenografted into immunodeficient mice and diminished their tumorigenic characteristics in vitro. Further, reduction of CD99 expression resulted in neurite outgrowth and increased expression of β-III tubulin and markers of neural differentiation. Analysis of a panel of human EWS cells revealed an inverse correlation between CD99 and H-neurofilament expression, as well as an inverse correlation between neural differentiation and oncogenic transformation. As knockdown of CD99 also led to an increase in phosphorylation of ERK1/2, we suggest that the CD99-mediated prevention of neural differentiation of EWS occurs through MAPK pathway modulation. Together, these data indicate a new role for CD99 in preventing neural differentiation of EWS cells and suggest that blockade of CD99 or its downstream molecular pathway may be a new therapeutic approach for EWS.