Growth and survival of B-chronic lymphocytic leukaemia cells

Although chronic lymphocytic leukaemia of B-cell type (B-CLL) is the most common form of leukaemia in the Western world, several questions about the biology of B-CLL remain to be clarified. To obtain a conceptual model for B-CLL, defined as a relentless accumulation of resting B-CLL cells, it is particularly relevant to ask which cell type is the normal counterpart of B-CLL; what is the site of proliferation; which signals are involved in the recruitment and induction of proliferation and which signals contribute to the survival of the B-CLL cells? The significance of the studies on B-CLL cellsin vitro for the interpretation of thein vivo situation may be questioned since they oversimplify the multiple and complex cellular interactions that occurin vivo. However, thein vitro studies have been instrumental in elucidating signals that may regulate growth, differentiation and survival of B-CLL cells. This knowledge, herein reviewed, can be used to put forward a hypothesis on B-CLL cell regulationin vivo.     

Estrogenic and antiproliferative activities on MCF-7 human breast cancer cells by flavonoids

The interaction between the estrogen receptor and a variety of flavonoids was studied in the presence or absence of estradiol using a stably-transfected human breast cancer cell line (MVLN). On the other hand, flavonoids were evaluated for their effects on proliferation in estrogen-dependent (MCF-7) and independent (MDA-MB231) human breast cancer cells. We established a relationship structure-activity and determined regions and/or substituents essential for estrogenic or antiestrogenic activities. In contrast, we did not find the same relationship for cell proliferation. Among all flavonoids used, only 7-methoxyflavanone and 7,8-dihydroxyflavone at high concentrations (50 μM) possess antiestrogenic and antiproliferative activities. These results suggest that two hydroxyls (in positions 7 and 8) or 7-methoxy substituents are essential for the antiestrogenic activity of flavonoids. However, it seems that flavonoids at high concentrations exert their antiproliferative activity through other estrogen receptor-independent mechanisms.     

Initial transforming event in myelodysplastic syndromes may be viral: case for cytomegalovirus

Myelodysplastic syndromes (MDS) are clonal hematopoietic disorders which begin in a pluripotential bone marrow (BM) stem cell. This early stem cell is believed to acquire a growth advantage over its neighbors as a result of an initial transforming event, the nature of which has remained obscure. In this paper, we propose that pathogens such as those belonging to the herpesvirus family of DNA viruses may play a role in the initial transformation of the stem cell. The case for cytomegalovirus (CMV) as a representative of this family of viruses is discussed at length and a molecular mechanism which may be involved in the oncogenic activity of CMV is proposed. No proof has been presented to implicate CMV directly in MDS, but circumstantial evidence which supports such a possibility is provided.     

Targeted disruption of GAP-43 in P19 embryonal carcinoma cells inhibits neuronal differentiation. As well as acquisition of the morphological phenotype

GAP-43 is expressed in proliferating neuroblasts in vivo and in vitro, but its role during early neurogenesis has not been investigated. Here we show that neuroectodermal differentiation stimulated by retinoic acid (RA) in the embryonal carcinoma (EC) line P19 is accompanied by upregulation of GAP-43 expression in neuroepithelial precursor cells. In contrast, when upregulation of GAP-43 expression was prevented in 3 independent P19 lines because of a targeted insertion into the gene, generation of neuroepithelial precursors was inhibited. Consequently, neuronal number was significantly decreased, neuronal morphology was abnormal and fewer than 20% of all neurons were able to initiate neuritogenesis. Extracellular matrix (ECM) was unable to rescue initiation of neuritogenesis in the mutant cells, however those neurites that were extended responded normally to ECM-stimulated neurite outgrowth-promoting signals. These data suggest that GAP-43 function is required for commitment to a neuronal phenotype as well as initiation of neurite extension. However, stimulation of neurite outgrowth by ECM in P19s occurs independently of GAP-43.     

丹酚酸B对PDGF及MDA诱导的人鼠原代肝星状细胞增殖的影响

目的：探讨丹酚酸B（SAB）对血小板生长因子（PDGF）和丙二醛（MDA）刺激的大鼠原代肝星状细胞（HSC）增殖的影响。方法：采用原位灌注法消化大鼠肝脏，108g／L Nycodenz密度梯度离心，分离HSC，以MTT法观察细胞的增殖能力。免疫组化法检测血小板生长因子受体（PDGFR）含量。结果：MDA组与正常组相比可明显增加MTT吸光度（P〈0．05），PDGF组亦较正常组明显增加MTT吸光度（P〈0．01）；1μmol／LSAB和10μmol／L SAB不仅可显著抑制MDA刺激的HSC吸光度增加（P均〈0．01），也可抑制PDGF—BB刺激的HSC吸光度增加（P均〈0．01）。PDGF及MDA作用后细胞PDGFR的表达均明显增加，而10μmol／L SAB则可抑制PDGFR的表达。结论：SAB可通过抑制PDGFR的表达而抑制体外培养HSC的增殖．这种抑制作用与SAB的抗氧化作用有一定的关系。     

宫颈癌中HPA的表达与细胞增殖、血管生成和转移的关系

目的通过对宫颈癌组织中乙酰肝素酶(heparanase,HPA)、细胞核增殖相关抗原Ki-67和微血管密度的检测,探讨HPA在宫颈癌发生发展中的作用。方法采用免疫组化染色(S-P法)检测67例宫颈癌中HPA、Ki-67和CD34的表达,并与13例正常宫颈组织进行对照研究,分析HPA与患者临床特征、Ki-67和CD34之间的关系。结果67例宫颈癌中49例(73%)阳性表达,而正常13例宫颈组织中无一例阳性表达(P=0.000)。HPA与临床分期、淋巴结转移、细胞增殖和血管生成显著正相关(P值分别为0.001、0.012、0.000、0.000)。结论HPA可能在宫颈癌的发展、浸润、转移和血管生成中起重要作用,并与肿瘤细胞的增殖活性有关,可作为临床预测宫颈癌浸润转移的一个重要参考指标和有价值的治疗靶点。     

Human carcinogenic risk evaluation: an alternative approach to the two-year rodent bioassay.

An approach to the evaluation of carcinogenic risk resulting from exposure to a given chemical is presented in place of a reliance on two-year rodent bioassays. An emphasis is placed on evaluation of the potential DNA reactivity or increased cell proliferation that can be produced by a chemical. The special cases of immunosuppressive and estrogenic chemicals are considered. These evaluations are proposed to involve a combination of in vitro assays, computerized models, and short-term (up to 13 weeks) bioassays in rodents. The emphasis is on mechanistic understanding and evaluation of the dose response and relevance to humans.     

SETD5介导AKT1磷酸化调控结肠癌细胞的迁移和5-FU敏感性

目的：探讨含SET结构域蛋白5（SETD5）对结肠癌细胞增殖、迁移和对5-氟尿嘧啶（5-FU）药物敏感性的影响及机制。方法：常规培养结肠癌细胞,用Lipofectamine 2000将siSETD5-NC、si-SETD5-1~3质粒转染至HT-29细胞中,将其分为对照组（未处理）、si-SETD5-NC组、si-SETD5组和si-SETD5+SC79组,si-SETD5+SC79组HT-29细胞转染质粒的同时用10 μmol/L SC79处理。qPCR法检测NCM460、HT-29和LoVo细胞中SETD5 mRNA表达,流式细胞术、细胞划痕法、WB法和CCK-8法分别检测各组HT-29细胞的凋亡情况、迁移能力、相关蛋白的表达,以及对5-FU 的敏感性。结果：SETD5 mRNA在HT-29、LoVo细胞中均呈高表达（均P<0.01）。在HT-29细胞中成功地敲减了SETD5 mRNA（P<0.01）。敲减SETD5 mRNA可明显抑制HT-29细胞的增殖活性（P<0.01）、迁移能力（P<0.01）、相关蛋白（SETD5、p-PI3K、p-AKT1、p-mTOR 蛋白）的表达（均P<0.01）、促进细胞凋亡（P<0.01）,且提高其对 5-FU 的敏感性（P<0.01）,这些作用均可被 AKT 激活剂 SC79 部分阻挡（P<0.05 或 P<0.01）。结论：SETD5在HT-29、LoVo细胞中高表达,SETD5通过PI3K/AKT1通路促进结肠癌HT-29细胞的增殖、迁移,且降低其对5-FU的敏感性,SETD5是结肠癌临床诊断、治疗的潜在靶点。     

内源性一氧化碳对肺动脉平滑肌细胞增殖基因表达谱的影响

目的 运用芯片技术研究内源性一氧化碳（CO）刺激下血管平滑肌细胞内增殖相关基凼表达谮的变化。方法 取SD大鼠肺动脉平滑肌细胞进行离体培养,用血小板源性生长因子（PDGF,20ng／m1）和Hemin（20μmol／L）进行刺激后,用Affymetrix表达基因谱芯片检测其基因表达谱变化。结果 Hemin刺激与PDGF刺激相比差异表达基因366条,与增殖相关的差异表达基因21条,上调11条,下调10条。其中原来在PDGF刺激下上调表达的一些基因（Map2k3、cyclinD1、PDGFA、mybL1、a．nape10、MMP14等）在经内源性CO刺激后其表达则显著下调。结论 内源性CO很可能是通过作用于MAPK途径来抑制PDGF的促增殖功能,同时伴有cyclinD1、cyclinG1、P21等的参与。