脐血干细胞分化的巨核细胞信号转导基因表达的分析

目的研究脐血干细胞向巨核细胞分化后信号转导基因表达的改变。方法分别收集同一份脐血分化培养前CD34＋细胞和培养后CD41＋细胞,提取总RNA。用基因芯片技术比较两组之间的基因表达差异,并用RT-PCR技术验证芯片结果。结果芯片分析结果显示,共筛选出3522个差异基因,其中上调1705个,下调1817个。3522个差异基因中,与细胞信号相关的基因有343个,与转录调节相关的有150个,与分化相关的有21个。其中,CD61基因的表达增加了369.83倍,CD41基因的表达增加27.38倍,PF4基因的表达增加24.06倍;MAPKs、GPCRs（G蛋白偶联受体）、RAS家族相关的基因多数表达上调;与STAT通路相关的基因中,SOCS1、JAK2表达上调,STAT5A表达下调。结论TPO等造血生长因子可能主要通过GPCRs-Ras-MAPK途径,促进脐血干细胞向巨核细胞系增殖、分化。     

Erlotinib and gefitinib for the treatment of myelodysplastic syndrome and acute myeloid leukemia: a preclinical comparison

Erlotinib and gefitinib, two inhibitors of the epidermal growth factor receptor (EGFR), can stimulate apoptosis and differentiation of myeloid cell lines that lack EGFR, unveiling a novel, therapeutically exploitable off-target effect of tyrosine kinase inhibitors. Here, we performed a side-by-side comparison of erlotinib and gefitinib effects on a broad spectrum of malignant myeloid cell lines, as well as on primary myeloblasts freshly purified from the bone marrow of patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Both erlotinib and gefitinib induce apoptosis of a cell line (KG-1) that represents AML, and differentiation in another cell line (P39) derived from a patient with high-risk MDS. In this setting, erlotinib was more efficient than gefitinib. Erlotinib and gefitinib were equipotent in inducing apoptosis of primary CD34⁺ myeloblasts from MDS and AML patients, yet had no toxic effect on CD34⁺ progenitor cells from healthy donors. Although the response of individual MDS and AML patients in vitro was highly heterogeneous, the pro-apoptotic effects of erlotinib and gefitinib correlated significantly. These results suggest that erlotinib and gefitinib share a mechanistically related off-target effect that may be taken advantage of for the therapy of MDS and AML.     

三氧化二砷诱导NB4细胞的基因表达谱改变

目的：研究三氧化二砷在诱导急性早幼粒细胞白血病细胞株NB4分化过程中基因表达谱的改变．方法：通过逆转录方法将经过及未经过三氧化二砷处理的NB4细胞mRNA制备成两种探针,应用Cy3和Cy5两种荧光染料分别标记这两种探针,随后与包含1003条待研究人类基因的表达谱基因芯片杂交,通过扫描和计算机软件分析,寻找经三氧化二砷作用后表达有差异的基因．结果：NB4细胞在三氧化二砷(0．5μmol／L)作用后3条基因上调,18条基因下调．1条参与蛋白酶体降解途径的基因显著上调,多条与细胞信号传导、RNA加工及蛋白质合成相关基因下调．结论：PSMB6及ITGBI基因的表达改变可能与NB4细胞的凋亡和／或分化有密切关系．     

Human CD34+ progenitor hematopoiesis in liquid culture for in vitro assessment of drug-induced myelotoxicity

Utilization of validated CFU-GM assays for myelotoxicity screening is hampered by its labor-intensive and low-throughput nature. Herein, we transformed the defined CFU-GM assay conditions and IC₉₀ endpoint into a higher throughput format. Human CD34⁺ hematopoietic progenitors were cultured in a 96-well plate for 14 days with the same cytokine (rhGM-CSF) used in the CFU-GM assay. Expansion and differentiation toward myeloid lineages were manifested by characteristic changes in nuclear and cytoplasmic morphology and by temporal expression patterns of CD34, CD11b and CD13 markers. Inhibition of CD34⁺ cell myelopoiesis by 12 anticancer drugs known to induce myelotoxicity in the clinic was quantifiable using either general cytotoxicity endpoints (cell growth area or total nucleus count) or lineage specific readouts (count of cells expressing CD11b and/or CD13). The IC₅₀ and IC₉₀ values derived from the concentration-response curves of 14-day drug exposure in CD34⁺ cell culture were highly correlated with those from the international validation study of the CFU-GM assay, demonstrating capability to assess general cytotoxicity, cell proliferation and myelopoiesis simultaneously. These results suggest that this human CD34⁺ hematopoietic progenitor cell assay can be used as a direct replacement for the validated, low throughput CFU-GM assay, and could expand application of in vitro myelotoxicity testing.     

Benzo[a]pyrene and glycine N-methyltransferse interactions: gene expression profiles of the liver detoxification pathway

Benzo[a]pyrene (BaP) is one of many polycyclic aromatic hydrocarbons that have been identified as major risk factors for developing various cancers. We previously demonstrated that the liver cancer susceptibility gene glycine N-methyltransferase (GNMT) is capable of binding with BaP and protecting cells from BaP-7,8-diol 9,10-epoxide-DNA adduct formation. In this study, we used a cytotoxicity assay to demonstrate that the higher expression level of GNMT, the lower cytotoxicity occurred in the cells treated with BaP. In addition, a cDNA microarray containing 7,597 human genes was used to examine gene expression patterns in BaP-treated HepG2 (a liver cancer cell line that expresses very low levels of GNMT) and SCG2-1-1 (a stable HepG2 clone that expresses high levels of GNMT) cells. The results showed that among 6,018 readable HepG2 genes, 359 (6.0%) were up-regulated more than 1.5-fold and 768 (12.8%) were down-regulated. Overexpression of GNMT in SCG2-1-1 cells resulted in the down-regulation of genes related to the detoxification, kinase/phosphatase pathways, and oncogenes. Furthermore, real-time PCR was used to validate microarray data from 21 genes belonging to the detoxification pathway. Combining both microarray and real-time PCR data, the results showed that among 89 detoxification pathway genes analyzed, 22 (24.7%) were up-regulated and 6 (6.7%) were down-regulated in BaP-treated HepG2 cells, while in the BaP-treated SCG2-1-1 cells, 12 (13.5%) were up-regulated and 26 (29.2%) were down-regulated (P < 0.001). Therefore, GNMT sequesters BaP, diminishes BaP's effects to the liver detoxification pathway and prevents subsequent cytotoxicity.     

Pluripotent stem cells exhibiting similar characteristics can be isolated from human fetal bone marrow,heart,liver,muscle,lung,derma,kidney,and fat

Previously, we reported that a cell population derived from human fetal bone marrow (BM), termed here Flk1⁺CD34⁻ postembryonic pluripotent stem cells (PPSCs) that have the characteristics of mesenchymal stem cells (MSCs), could differentiate into ectodermal, endodermal and mesodermal cell types at the single cell level in vitro, and that these cells could also differentiate into the epithelium of liver, lung, gut, as well as the hematopoietic and endothelial lineages after transplantion into irradiated non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice. In this study, we further isolated pluripotent stem cells from human fetal heart, liver, muscle, lung, derma, kidney, and fat and then analyzed the characteristics and function of these stem cells. It was found that the phenotype of the culture-expanded pluripotent stem cells from different fetal tissues was similar to BM-derived Flk1⁺CD34⁻ PPSCs, i.e. Flk1 and CD44 positive, GlyA, CD34, CD45, class I-HLA and HLA-DR negative. Morphologically, these cells were fibroblast-like and the doubling time was about 30 h. More importantly, culture-expanded pluripotent stem cells from all these fetal tissues were able to differentiate into cells with morphologic and phenotypic characteristics of adipocytes, osteocytes, neurons, glial cells and hepatocytes. These pluripotent stem cells with characteristics similar to fetal BM-derived Flk1⁺CD34⁻ PPSCs can be selected and cultured from tissues other than the BM. This phenomenon may help explain the “stem cell plasticity” found in multiple human tissues. In addition, as fetal BM-derived Flk1 + CD34⁻ PPSCs, these pluripotent stem cells from different fetal tissues had the capacity for self-renewal and multi-lineage differentiation even after being expanded for more than 40 population doublings in vitro. Thus, they may be an ideal source of stem cells for treatment of inherited or degenerative diseases.     

基因芯片技术研究Z24对人HepG2细胞基因表达的影响

目的:利用芯片技术观察Z24对人HepG2细胞基因表达的影响,以探讨其毒性作用的分子机制.方法:不同浓度处理培养的HepG2细胞,H-E染色观察细胞形态;抽提细胞RNA,利用荧光标记ddUTP逆转录制备cDNA探针,与毒理表达谱基因芯片杂交,并对Cy3,Cy5荧光信号做扫描分析.结果:Z24处理实验组细胞呈现凋亡形态;芯片扫描显示在IC20浓度情况下,Z24作用HepG2细胞有15个基因发生显著的变化,其中细胞凋亡通路有关的基因TNFRSF5发生明显上调,与肝功能有关的基因(AKR1C2和INSIG1)发生明显的下调.随Z24浓度的增加,发生改变的基因数增加到244个,其中109个基因发生明显的上调,135个基因发生明显的下调,下调的基因多与细胞增殖调控功能、氨基酸、能量和脂肪代谢有关;而细胞凋亡通路中几个重要关键蛋白(DFFB,CASP6,DR4)的基因明显上调,并且与肝脏有关的基因(INSIG1,PHKA2,HPX)也发生了明显的改变.结论:Z24可以诱导HepG2细胞凋亡,并可能是其产生毒性的重要机制之一;毒性作用的靶器官可能是肝脏.     

Valproic acid enhances pamidronate-sensitized cytotoxicity of Vδ2+ T cells against EBV-related lymphoproliferative cells

Therapeutic options for Epstein–Barr virus (EBV)-associated post-transplantation lymphoproliferative diseases (PTLD) are currently limited, accompanying with some off-target toxicities. We previously demonstrated that early recovery of Vδ2⁺ T cells inversely correlated to EBV reactivation after allogeneic hematopoietic cell transplantation. Studies in vitro and in the mouse models showed the cytotoxic activity of Vδ2⁺ T cells on EBV-transformed lymphoproliferative cells, but the efficacy was moderate. Bisphosphonate, such as pamidronate (PAM), have been reported as a sensitizer to trigger tumor cells for Vδ2⁺ T cells recognition. Valproic acid (VPA) has attracted attentions due to its adjuvant anti-tumor effect with chemotherapy or immunotherapy. Whether PAM and VPA facilitate the immunogenicity of EBV-infected cells towards Vδ2⁺ T cells cytotoxicity remains unknown. Herein, we demonstrated that lower dosage of VPA and/or PAM did not induce apoptosis of EBV-transformed B lymphoblastoid cell lines (EBV-LCLs) or Vδ2⁺ T cells. Notably, pre-treatment with PAM significantly increased the cell death of EBV-LCLs after co-culture with Vδ2⁺ T cells at different ratios. Combining treatment with VPA reinforced the sensitizing effect of PAM. This efficacy was through inducing the accumulation of mevalonate pathway intermediates and dependent on the γδ T cell receptor of Vδ2⁺ T cells. Similar sensitizing effects of PAM and PAM plus VPA were also demonstrated on the primary PTLD cells. These results highlight the roles of PAM and VPA in the enhancement of immune surveillance and expand the fields of these two drugs in the treatment of different types of malignancies.     

Midostaurin (PKC412) modulates differentiation and maturation of human myeloid dendritic cells

Midostaurin, a tyrosine kinase inhibitor, has been shown efficacy against acute myeloid leukemia and various other malignancies in clinical trials. Prior studies indicate midostaurin affects the function of immune cells such as lymphocytes and macrophages. To understand the effect of midostaurin on human myeloid dendritic cells (DCs), we conducted an ex vivo study using immature DCs differentiated from CD14⁺ monocytes and further maturated using lipopolysaccharide. Addition of midostaurin to a culture of starting CD14⁺ monocytes markedly and dose-dependently reduced DC recovery. Mature DCs differentiating in the presence of midostaurin had fewer, shorter cell projections than those differentiating in the absence of midostaurin. Changes in morphological features characteristic of apoptotic cells were also evident. Moreover, midostaurin affected DC differentiation and maturation patterns; CD83 expression levels decreased, whereas CD14 and CD80 expressions increased. Additionally, DCs derived in the presence of midostaurin possessed a lower endocytotic capacity and less allostimulatory activity on naive CD4⁺CD45⁺RA⁺ T cell proliferation than those derived in its absence, suggesting that midostaurin redirects DC differentiation toward a less mature stage and that this effect is not solely due to its cytotoxicity. Whether this effect underlies immune suppression or tolerance to disease treatments with unwanted immune reactions needs further evaluation.     

High cholesterol diet increases osteoporosis risk via inhibiting bone formation in rats

Aim:

To investigate the effects of high cholesterol diet on the development of osteoporosis and the underlying mechanisms in rats.

Methods:

Female Sprague-Dawley rats were randomly separated into 3 groups: (1) the high cholesterol fed rats were fed a high cholesterol diet containing 77% normal diet food, 3% cholesterol and 20% lard for 3 months; (2) ovariectomised (OVX) rats were bilaterally ovariectomised and fed a standard diet; and (3) the control rats were fed the standard diet. Bone mineral density (BMD) of the rats was measured using dual-energy X-ray absorptiometry. Serum levels of oestradiol (E2), osteocalcin (BGP) and carboxy-terminal collagen crosslinks (CTX) were measured using ELISA. Gene expression profile was determined with microarray. Mouse osteoblast cells (MC3T3-E1) were used for in vitro study. Proliferation, differentiation and oxidative stress of the osteoblasts were investigated using MTT, qRT-PCR and biochemical methods.

Results:

In high cholesterol fed rats, the femur BMD and serum BGP level were significantly reduced, while the CTX level was significantly increased. DNA microarray analysis showed that 2290 genes were down-regulated and 992 genes were up-regulated in this group of rats. Of these genes, 1626 were also down-regulated and 1466 were up-regulated in OVX rats. In total, 370 genes were up-regulated in both groups, and 976 genes were down-regulated. Some of the down-regulated genes were found to code for proteins involved in the transforming growth factor beta (TGF-β)/bone morphogenic protein (BMP) and Wnt signaling pathways. The up-regulated genes were found to code for IL-6 and Ager with bone-resorption functions. Treatment of MC3T3-E1 cells with cholesterol (12.5-50 μg/mL) inhibited the cell proliferation and differentiation in vitro in a concentration-dependent manner. The treatment also concentration-dependently reduced the expression of BMP2 and Cbfa1, and increased the oxidative injury in MC3T3-E1 cells.

Conclusion:

The results suggest a close correlation between hypercholesterolaemia and osteoporosis. High cholesterol diet increases the risk of osteoporosis, possible via inhibiting the differentiation and proliferation of osteoblasts.     

人类造血细胞抗原(huHCA)阳性急性髓系白血病细胞形态学及免疫学分型

目的 :研究人类造血细胞抗原阳性急性髓系白血病细胞的生物学特征。方法 :应用间接免疫荧光法 ,通过流式细胞仪和光学显微镜对 11例 HCA+ AML 患者进行形态学、免疫表型检测。结果 :11例 HCA+ Am L 患者 ,8例CD+ 1 3、9例 CD+ 33、2例 CD+ 1 5 、7例 CR+、5例 CD+ 34 、1例 CD+ 7、1例 CD+ 1 0 、2例 CD+ 1 9、1例 CD+ 2 2 。在 FAB分型中 ,髓淋混合型、M2 、M5 表达 HCA阳性率明显高于其它亚型 ,各型间差异无统计学意义。 HCA+ 部分白血病细胞同时表达 CD13/CD33/ DR/ CD34。结论 :HCA在 AML 中的表达 ,与 FAB亚型无关 ,但髓淋混合型、M2 、M5 阳性率明显高于其它亚型。HCA+细胞分化程度较低 ,具有髓系细胞特征。     

Current topics in pharmacological research on bone metabolism: Promyelotic leukemia zinc finger (PLZF) and tumor necrosis factor-alpha-stimulated gene 6 (TSG-6) identified by gene expression analysis play roles in the pathogenesis of ossification of the posterior longitudinal ligament

To understand the molecular pathogenesis of ossification of the posterior longitudinal ligament of the spine (OPLL), an ectopic bone formation disease, we performed cDNA microarray analysis on cultured ligament cells from OPLL patients to understand the molecular pathogenesis of OPLL. We identified promyelotic leukemia zinc finger (PLZF) as one of up-regulated genes and tumor necrosis factor-alpha-stimulated gene 6 (TSG-6) as one of down-regulated gene during osteoblastic differentiation. We investigated the roles of PLZF in the regulation of osteoblastic differentiation of human mesenchymal stem cells (hMSCs) and C2C12 cells. siRNA-mediated gene-silencing of PLZF resulted in a reduction of the expression of osteoblast-specific genes such as the alkaline phosphatase, collagen 1A1, Runx2/CBFA1, and osteocalcin genes in the presence of osteogenic differentiation medium (OS) in hMSCs. The overexpression of PLZF induced CBFA1 induction, suggesting that PLZF is an upstream regulator of CBFA1 and thereby participates in promoting the ossification of spinal ligament cells in OPLL patients. Adenovirus-mediated TSG-6 overexpression in hMSCs resulted in suppression of osteoblastic differentiation induced by either BMP-2 or OS. TSG-6 can bind to BMP-2 directly and thereby could inhibit BMP-2 signaling. Taken together, these findings indicate that PLZF and TSG-6 play important roles in early osteoblastic differentiation.     

DNA微矩阵芯片检测沙利度胺对HepG2细胞基因表达谱的影响

目的　从整个细胞基因组表达变化的角度 ,研究沙利度胺 (Tha)对基因表达谱的影响 ,揭示发育毒性药物的致畸机制。方法　用载有 8192条基因的DNA微矩阵芯片 ,检测在 11.6μmol·L- 1的Tha作用4 2h后 ,HepG2细胞基因表达谱的变化。结果有 19条基因的表达有明显变化 ,其中 17条基因表达下调 ,2条基因表达上调。下调基因中有多条为转录调控和胚胎发育相关基因 ,上调的基因中有DNA修复相关基因和线粒体功能相关的基因。结论　Tha能影响若干基因转录和胚胎发育基因的表达 ,可能与其发育毒性机制相关 ,为发展新的发育毒性药物评价方法提供了有利基础