IN-VITRO IMMUNOTOXICITY AND CYTOTOXICITY OF TRICHOSANTHIN AGAINST HUMAN NORMAL IMMUNOCYTES AND LEUKEMIA-LYMPHOMA CELLS

Trichosanthin (TCS) is a ribosome-inactivating protein from root tubers of Trichosanthes kirilowii Maxim. In this paper, the effects of TCS on the viability of human peripheral blood immunocytess, on the proliferation of lymphocytes, and its cytotoxicity to twelve cell lines of lymphoma or leukemia had been observed. TCS at high concentration (>12.5 mu g/ml) affected the viability of human B lymphocytes, but not that of human peripheral blood mononuclear cells (PBMCs), T lymphocytes and granulocytes. Human peripheral blood-derived monocytes/macrophages were highly sensitive to TCS (ID50 at 1.70 mu g/ml). TCS suppressed lymphocyte proliferation stimulated by Concanavalin A (Con A) or lipopolysaccharide (LPS). Human T cell lines and macrophage cell lines were more sensitive (ID50 < 0.9 mu g/ml) to TCS than B cell lines and myeloid lines. These results suggest that selective cytotoxicity of TCS to human macrophages/monocytes may be implicated in anti-HIV activity, and that selectively killing some leukemia-lymphoma cells by TCS merit further evaluation in treatment of some lymphoma and leukemia.

U19/Eaf2 knockout causes lung adenocarcinoma, B-cell lymphoma, hepatocellular carcinoma and prostatic intraepithelial neoplasia

Upregulated gene 19 (U19)/ELL-associated factor 2 (Eaf2) is a potential human tumor suppressor that exhibits frequent allelic loss and downregulation in high-grade prostate cancer. U19/Eaf2, along with its homolog Eaf1, has been reported to regulate transcriptional elongation via interaction with the eleven-nineteen lysine-rich leukemia (ELL) family of proteins. To further explore the tumor-suppressive effects of U19/Eaf2, we constructed and characterized a murine U19/Eaf2-knockout model. Homozygous or heterozygous deletion of U19/Eaf2 resulted in high rates of lung adenocarcinoma, B-cell lymphoma, hepato cellular carcinoma and prostate intraepithelial neoplasia. Within the mouse prostate, U19/Eaf2 defficiency enhanced cell proliferation and increased epithelial cell size. The knockout mice also exhibited cardiac cell hypertrophy. These data indicate a role for U19/Eaf2 in growth suppression and cell size control as well as argue for U19/Eaf2 as a novel tumor suppressor in multiple mouse tissues. The U19/Eaf2 knockout mouse also provides a unique animal model for three important cancers: lung adenocarcinoma, B-cell lymphoma and hepatocellular carcinoma.

Expression of syncytin in leukemia and lymphoma cells

Syncytin is a placenta-specific protein and generally believed to play a pivotal role in syncytiotrophoblast morphogenesis. In this study, transcripts of this gene were quantified by real-time RT-PCR and the translated products were measured by an indirect immunofluorescence assay. Results showed that syncytin was found to be expressed in all nine leukemia and lymphoma cell lines studied albeit at different levels and in 43 peripheral blood samples of 57 leukemia or lymphoma patients. Neither the transcripts nor the translated syncytin was detected in blood samples of normal individuals. In conclusion, peripheral blood syncytin may serve as a marker for leukemia and lymphoma. ©

天花粉蛋白体外抗人白血病和淋巴瘤细胞的作用机制

本研究的目的是探讨天花粉蛋白(TCS)对人白血病和淋巴瘤细胞系的杀伤作用机制.用台盼蓝染色法检测TCS对细胞生长的影响,应用流式细胞术检测TCS诱导细胞凋亡的情况及对细胞生长周期的影响.结果表明:12.5μg/ml浓度的TCS可以显著抑制各种白血病细胞系的增殖,但对T淋巴细胞系和巨噬细胞细胞系表现为诱导细胞凋亡的作用,而对B淋巴瘤细胞系则表现为生长抑制效应.通过细胞周期检测发现,TCS可以将B淋巴瘤细胞系细胞阻滞在S期,从而抑制细胞增殖,但对T淋巴细胞系则无明显影响.结论:TCS以不同的作用机制杀伤白血病细胞,根据不同的细胞类型分别表现为诱导细胞凋亡和阻滞细胞生长周期的作用.

合胞素在白血病和淋巴瘤细胞中的表达及意义研究

人类内源性病毒(HERVs)是远古具有感染能力的逆转录病毒整合于人类基因组的遗迹, 大约占人类基因组的3%~8%，至少包括31个家族。它们通过不同的途径参与人类各种生理和病理活动的调节过程。大多数人类内源性病毒的基因, 由于基因的突变或部分缺失而失去了转录的能力。但有些基因依然保持完整的开放读码框, 能翻译成有功能的蛋白, 如HERV-W家族的囊膜蛋白合胞素基因, 可以被转录并翻译成有功能的蛋白质。目前合胞素的生理功能以及在各种病理过程中的作用机制仍然不清楚。国内对于合胞素的功能研究处于起步阶段，尚无商品化试剂，而且也没有合胞素抗体制备的报道。我们通过PCR扩增人合胞素基因编码区的DNA片段，将其克隆入原核表达质粒pET30a (+)，转化大肠杆菌 BL21，诱导产生了合胞素-His融合蛋白。采用割胶回收的方法纯化目的蛋白, 免疫新西兰白兔, 制备了多克隆抗体。最后通过ELISA、Western-Blot和免疫组织化学等方法检测抗体的效价和特异性。我们成功表达并纯化了合胞素-His融合蛋白, SDS-PAGE分析表明融合蛋白主要以包涵体形式存在；ELISA法测定抗体效价为 1:10 000；Western-Blot和免疫组织化学结果显示所制备的抗体能特异性识别合胞素蛋白，为下一步研究合胞素的生物学功能奠定了基础。我们首次发现，合胞素能够在白血病和淋巴瘤细胞系中表达。利用我们制备的抗合胞素多克隆抗体，我们进一步检测该基因是否在白血病和淋巴瘤患者的外周血中表达，所有患者的外周血标本，均来自云南省有关医院。作为对照，我们还检测了20 名健康志愿者的外周血细胞。实验证明，合胞素基因(包括 mRNA 和蛋白)也在白血病患者的外周血细胞表达，而不表达于健康志愿者的血细胞。在30 名不同的白血病和淋巴瘤患者中，有22 名有合胞素的表达。荧光实时定量RT-PCR 的方法比较了合胞素在细胞系和白血病患者外周血中表达的相对定量，发现合胞素基因在所检测的5 种淋巴细胞系、3 种粒细胞系和1 种淋巴瘤细胞系中都有相对稳定的表达，表达水平与C8166 细胞系相比，介于0.5-2 倍之间。而在白血病患者中的表达则介于1.8-33.4 倍不等。我们的结果提示，合胞素可能与白血病的形成有关，因为该基因表达的囊膜蛋白具有很强的促细胞融合活性，含有具有免疫抑制活性的肽段，而且已发现某些与其类似的蛋白有致瘤能力。

Study on bioactivity of extracts from marine sponges in Chinese Sea

The bioactivity screening of fractions from two inter-tidal sponges collected from the north of China Yellow Sea and one sponge collected from the South Chinese Sea was reported in this study. In sponge Hymeniacidon perleve there were 9 fractions out of 15 from CHCl3 extract with anti Staphylococcus aureus activity, 9 fractions out of 19 from BuOH extract with anti Escherichia coli activity, and three fractions from CHCl3 extract which had moderate to strong activity in inhibiting Bacillus subtilis, Candida albicans, and Aspergilus niger. The fractions of Reniochalina sp. showed bioactivity against bacteria and fungi. The fractions of Acanthella acuta Schmidt showed bioactivity against S. aureus and fungi. One compound from H. perleve obtained by the bioactively directing isolation was tested for bioactivity against the human hepatoma cell line Qgy7701 (IC50 10.1 mug/ml), Burkitt's lymphoma cell line Raji (IC50 9.76 mug/ml) and chronic myelogenous leukemia K562 (IC50 1.90 mug/ml). (C) 2003 Elsevier B.V. All rights reserved.