Differential expression and biochemical activity of the immune receptor Tim-3 in healthy and malignant human myeloid cells

The T cell immunoglobulin and mucin domain 3 (Tim-3) is a plasma membrane-associated receptor which is involved in a variety of biological responses in human immune cells. It is highly expressed in most acute myeloid leukaemia (AML) cells and therefore may serve as a possible target for AML therapy. However, its biochemical activities in primary human AML cells remain unclear. We therefore analysed the total expression and surface presence of the Tim-3 receptor in primary human AML blasts and healthy primary human leukocytes isolated from human blood. We found that Tim-3 expression was significantly higher in primary AML cells compared to primary healthy leukocytes. Tim-3 receptor molecules were distributed largely on the surface of primary AML cells, whereas in healthy leukocytes Tim-3 protein was mainly expressed intracellularly. In primary human AML blasts, both Tim-3 agonistic antibody and galectin-9 (a Tim-3 natural ligand) significantly upregulated mTOR pathway activity. This was in line with increased accumulation of hypoxia-inducible factor 1 alpha (HIF-1α) and secretion of VEGF and TNF-α. Similar results were obtained in primary human healthy leukocytes. Importantly, in both types of primary cells, Tim-3-mediated effects were compared with those induced by lipopolysaccharide (LPS) and stem cell factor (SCF). Tim-3 induced comparatively moderate responses in both AML cells and healthy leukocytes. However, Tim-3, like LPS, mediated the release of both TNF-α and VEGF, while SCF induced mostly VEGF secretion and did not upregulate TNF-α release.     

咖啡因通过FAK/AKT/ROCK通路调控人脑胶质瘤U-373MG细胞的恶 性生物学行为

目的：探讨咖啡因通过调节FAK/AKT/ROCK信号通路来影响人脑胶质瘤U-373MG细胞的增殖、迁移和侵袭能力。方法：常规培养U-373MG细胞,将其分为对照组、咖啡因低剂量（1 mmol/L）组、咖啡因高剂量（2 mmol/L）组、PF573228组（FAK抑制剂,1 μmol/L）、咖啡因高剂量+SC79组（AKT激活剂,8 mg/L）。用CCK-8法、Transwell小室实验、流式细胞术和WB法分别检测各组U-373MG细胞的增殖、迁移、侵袭及凋亡,以及U-373MG细胞中p-FAK、p-AKT、p-ROCK、Ki67、MMP-9蛋白表达水平。建立U-373MG细胞裸鼠移植瘤模型,观察咖啡因对移植瘤生长的影响,WB法检测移植瘤组织中相关蛋白的表达。结果：咖啡因、PF573228可显著抑制U-373MG细胞的增殖、迁移、侵袭能力,促进U-373MG细胞凋亡,抑制p-FAK、p-AKT、p-ROCK、Ki67、MMP-9蛋白的表达（均P<0.05）,SC79则可部分逆转咖啡因对U-373MG细胞的作用（均P<0.05）。咖啡因可显著抑制移植瘤的生长及移植瘤组织中上述相关蛋白的表达（均P<0.05）。结论：咖啡因可通过抑制FAK/AKT/ROCK信号通路抑制U-373MG细胞的增殖、迁移和侵袭能力,并促进其凋亡。     

苦参碱通过bcr-abl介导的MEK-ERK通路抑制人慢性粒细胞白血病K562细胞增殖

目的：探讨MEK-ERK通路在苦参碱抑制人慢性粒细胞白血病K562细胞增殖中的分子机制。方法采用Western blot法检测K562细胞内MEK-ERK通路关键分子MEK1、ERK1／2及其上游接头分子Shc、SHP2的总蛋白和磷酸化蛋白的表达;采用反转录聚合酶链反应（RT-PCR）和Western blot检测bcr-abl及有丝分裂原激活的蛋白激酶（MAPK）下游靶蛋白bcl-xL、Cyclin D1、c-myc及p27在转录及蛋白水平的表达。结果苦参碱可明显抑制K562细胞内MEK1、ERK1／2及Shc、SHP2的磷酸化表达,并可在转录及蛋白水平抑制bcr-abl分子表达。同时,RT-PCR和Western blot实验证实,苦参碱处理后,K562细胞内bcl-xL、Cyclin D1、c-myc表达均明显抑制,细胞周期负调控蛋白p27的表达增加。结论苦参碱对K562细胞的抑制效应与bcr-abl介导的MEK-ERK信号通路活性抑制有关,对信号通路中磷酸化蛋白或激酶分子活性的调控可能是其调控MEK-ERK通路活性的重要分子机制。     

Resveratrol activates autophagic cell death in prostate cancer cells via downregulation of STIM1 and the mTOR pathway

Resveratrol (RSV), a natural polyphenol, has been suggested to induce cell cycle arrest and activate apoptosis‐mediated cell death in several cancer cells, including prostate cancer. However, several molecular mechanisms have been proposed on its chemopreventive action, the precise mechanisms by which RSV exerts its anti‐proliferative effect in androgen‐independent prostate cancer cells remain questionable. In the present study, we show that RSV activates autophagic cell death in PC3 and DU145 cells, which was dependent on stromal interaction molecule 1 (STIM1) expression. RSV treatment decreases STIM1 expression in a time‐dependent manner and attenuates STIM1 association with TRPC1 and Orai1. Furthermore, RSV treatment also decreases ER calcium storage and store operated calcium entry (SOCE), which induces endoplasmic reticulum (ER) stress, thereby, activating AMPK and inhibiting the AKT/mTOR pathway. Similarly, inhibition of SOCE by SKF‐96365 decreases the survival and proliferation of PC3 and DU145 cells and inhibits AKT/mTOR pathway and induces autophagic cell death. Importantly, SOCE inhibition and subsequent autophagic cell death caused by RSV was reversed by STIM1 overexpression. STIM1 overexpression restored SOCE, prevents the loss of mTOR phosphorylation and decreased the expression of CHOP and LC3A in PC3 cells. Taken together, for the first time, our results revealed that RSV induces autophagy‐mediated cell death in PC3 and DU145 cells through regulation of SOCE mechanisms, including downregulating STIM1 expression and trigger ER stress by depleting ER calcium pool. © 2015 The Authors. Molecular Carcinogenesis, published by Wiley Periodicals, Inc.     

Stimulated lymphoid cells of B lineage, but not plasma or myeloid cells, can express E receptor

After culture with 20-30% autologous or allogeneic T cells and PHA, at least a proportion of the pathological cells from a variety of B-cell proliferations (common acute lymphoblastic leukaemia, prolymphocytic leukaemia, non-Hodgkin's lymphoma with blood involvement by mature lymphoid (cleaved and non-cleaved) cells) expressed true endogenous sheep erythrocyte (E) receptors. In contrast, plasma cells and a variety of myeloid cells failed to express E receptors after similar in vitro stimulation. These data, taken in conjunction with previous findings with B cells from normals and patients with hairy-cell and chronic lymphocytic leukaemia, suggest that B cells earlier than plasma cells can express E receptors after appropriate stimulation. The findings provide an in vitro counterpart of the leukaemic proliferations expressing both E receptor and surface immunoglobulin described from various laboratories, and further question the lineage specificity of the E receptor.     

Pharmacological targeting of the PI3K/mTOR pathway alters the release of angioregulatory mediators both from primary human acute myeloid leukemia cells and their neighboring stromal cells

Acute myeloid leukemia (AML) is a heterogeneous and aggressive malignancy with poor overall survival. Constitutive as well as cytokine-initiated activation of PI3K/Akt/mTOR signaling is a common feature of AML patients, and inhibition of this pathway is considered as a possible therapeutic strategy in AML. Human AML cells and different stromal cell populations were cultured under highly standardized in vitro conditions. We investigated the effects of mTOR inhibitors (rapamycin and temsirolimus) and PI3K inhibitors (GDC-0941 and 3-methyladenin (3-MA)) on cell proliferation and the constitutive release of angioregulatory mediators by AML and stromal cells.Primary human AML cells were heterogeneous, though most patients showed high CXCL8 levels and detectable release of CXCL10, Ang-1, HGF and MMP-9. Hierarchical clustering analysis showed that disruption of PI3K/Akt/mTOR pathways decreased AML cell release of CXCL8-11 for a large subset of patients, whereas the effects on other mediators were divergent. Various stromal cells (endothelial cells, fibroblasts, cells with osteoblastic phenotype) also showed constitutive release of angioregulatory mediators, and inhibitors of both the PI3K and mTOR pathway had anti-proliferative effects on stromal cells and resulted in decreased release of these angioregulatory mediators. PI3K and mTOR inhibitors can decrease constitutive cytokine release both by AML and stromal cells, suggesting potential direct and indirect antileukemic effects.     

急性髓系白血病细胞对树突状细胞分化、成熟和调节性T细胞生成的影响

Objective To investigate the effects of soluble factors secreted by acute myeloid leukemia (AML) cells on the phenotypical and functional properties of DCs derived from normal mononuclear cells. Methods Mononuclear cells were cultured with interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF), in the presence or absence of 24 h culture supernatants from fresh primary AML cells, to generate immature DCs. The maturation of DCs was induced by cytokines IL-1beta, IL-6, tumor necrosis factor-alpha (TNF-alpha), and prostaglandin-2 (PGE-2). The phenotypic alterations of DCs and DCs-primed CD4 T cells were evaluated using flow cytometry. Precursor frequency (PF) was calculated to monitor the allostimulatory effects of DCs on CD4 and CD8 T cells. ResultsAML cell supernatant-treated DCs showed significantly lower expression of co-stimulatory molecules CD80 and CD86, and reduced response to cytokines IL-1beta, IL-6, TNF-alpha,and PGE-2. The allostimulatory effects of AML cell supernatant-treated DCs on CD4 and CD8 T cells were significantly lower than those of normal mature DCs [PF (1.8±0.5)% vs. (5.2±1.6)% for CD4 T cells, (2.1±0.6)% vs. (6.5±2.0)%for CD8 T cells, P＜0.01]. These AML supematant-induced DCs could also induce allogeneic CD4 T cells to differentiate into CD4 CD25high T cells, which had immunophenotyping characteristics of regulatory T cells, i.e. they expressed Foxp3 but not active maker CD69. Conclusion This study demonstrates that soluble factors secreted by AML cells can inhibit development and functions of DCs. In addition, AML supematant-induced DCs can induce the generation of CD4 CD25high T cells from CD4 T cells, which may be a mechanism of increased prevalence of CD4 CD25high regulatory T cells and immune dysfunction in AML patients.     

Partial characterization of protein tyrosine kinase activity in normal and leukemic human myeloid cells

We have examined the expression of the protein tyrosine kinase (PTK) encoding oncogenes fes and abl in normal and malignant human myeloid cells in immunoblotting experiments. fes was markedly present in all cytosolic and most membrane fractions of normal and malignant cells. abl was only visible in normal cells, and occurred mostly in the cytosolic fractions. Molecular weights of identified proteins were different from the known products of fes and abl, possibly by alternative splicing at the mRNA level or by proteolysis. PTKs in myeloid cells were further purified by fast liquid protein chromatography (FPLC). PTK-activities of column fractions were assayed using a solid-phase non-radioactive dot-blot assay. Cytosolic and membrane fractions showed a FPLC pattern with a constant as well as a variable part in both normal and malignant cells, possibly indicative for PTKs with specialized functions in normal cell growth and transformation. Partial characterization of PTKs from different eluted peaks of AML-M4 blast cells demonstrated that PTKs from these peaks are kinetically distinct from each other.     

人骨髓间充质干细胞对慢性粒细胞白血病细胞增殖的影响及其机制探讨

背景与目的：我们先前的实验证明,在适宜的刺激下骨髓间充质干细胞（mesenchymal stem cells,MSCs）可分泌可溶性的细胞因子。本实验旨在研究MSCs对慢性粒细胞白血病（chronic myeloid leukemia,CML）细胞增殖的影响．并检测上清液中MSCs分泌的细胞因子。方法：采集健康供者骨髓培养MSCs,流式细胞仪检测第三代MSCs表面标记。将MSCs与不同浓度的CML患者的骨髓单个核细胞（chronic myeloid leukemia mononuclear cells,CML—MNC）共培养;每天收集各组CML—MNC计数取均值,绘制生长曲线。于实验的第3天和第6天收集各培养组的上清液,ELISA法测IFN-α。结果：原代和传代培养的细胞呈大的长梭形,增殖旺盛：细胞表面标记：CD44阳性,而CD45阴性。生长曲线示：与MSCs培养的CML—MNC增殖受抑。ELISA法检测结果示：对照组CML细胞生成IFN-α极低,显著低于各实验组,差异有统计学意义（P〈0．001）。MSCs与CML细胞共培养时可以分泌大量的IFN-α,且随着MSCs浓度的增加和共培养时间的延长,生成的IFN-α量增多。结论：MSCs与CML细胞共培养时能产生大量IFN-α抑制CML细胞增殖。     

Targeting the CXCL12/CXCR4 pathway and myeloid cells to improve radiation treatment of locally advanced cervical cancer

Cervical cancer is the fourth most commonly diagnosed cancer and the fourth leading cause of cancer death in women worldwide. Approximately half of cervical cancer patients present with locally advanced disease, for which surgery is not an option. These cases are nonetheless potentially curable with radiotherapy and cisplatin chemotherapy. Unfortunately, some tumours are resistant to treatment, and lymph node and distant recurrences are major problems in patients with advanced disease at diagnosis. New targeted treatments that can overcome treatment resistance and reduce metastases are urgently needed. The CXCL12/CXCR4 chemokine pathway is ubiquitously expressed in many normal tissues and cancers, including cervical cancer. Emerging evidence indicates that it plays a central role in cervical cancer pathogenesis, malignant progression, the development of metastases and radiation treatment response. Pre‐clinical studies of standard‐of‐care fractionated radiotherapy and concurrent weekly cisplatin plus the CXCR4 inhibitor Plerixafor (AMD3100) in patient‐derived orthotopic cervical cancer xenografts have shown improved primary tumour response and reduced lymph node metastases with no increase in early or late side effects. These studies have pointed the way forward to future clinical trials of radiotherapy/cisplatin plus Plerixafor or other newly emerging CXCL12 or CXCR4 inhibitors in women with cervical cancer.     

Vaccine-induced tumor regression requires a dynamic cooperation between T cells and myeloid cells at the tumor site

Most cancer immunotherapies under present investigation are based on the belief that cytotoxic T cells are the most important anti-tumoral immune cells, whereas intra-tumoral macrophages would rather play a pro-tumoral role. We have challenged this antagonistic point of view and searched for collaborative contributions by tumor-infiltrating T cells and macrophages, reminiscent of those observed in anti-infectious responses. We demonstrate that, in a model of therapeutic vaccination, cooperation between myeloid cells and T cells is indeed required for tumor rejection. Vaccination elicited an early rise of CD11b⁺ myeloid cells that preceded and conditioned the intra-tumoral accumulation of CD8⁺ T cells. Conversely, CD8⁺ T cells and IFNγ production activated myeloid cells were required for tumor regression. A 4-fold reduction of CD8⁺ T cell infiltrate in CXCR3KO mice did not prevent tumor regression, whereas a reduction of tumor-infiltrating myeloid cells significantly interfered with vaccine efficiency. We show that macrophages from regressing tumors can kill tumor cells in two ways: phagocytosis and TNFα release. Altogether, our data suggest new strategies to improve the efficiency of cancer immunotherapies, by promoting intra-tumoral cooperation between macrophages and T cells.     

Twist 1通过MPL促进髓系白血病细胞增殖和耐药

目的:检测Twist-1与骨髓增生性白血病病毒癌基因(myeloproliferative leukemia virus oncogene,MPL)在髓系白血病患者和髓系造血系统恶性肿瘤细胞系中表达的相关性,并探讨Twist-1是否通过MPL对髓系白血病细胞增殖、耐药发挥促进作用.方法:选取中国医学科学院血液病医院2005年1月至2008年12月初次诊断为急性髓系白血病(acute myeloid leu-kemia,AML)、慢性粒细胞白血病(chronic myeloid leukemia,CML)患者的骨髓标本41例(其中AML 23例、CML 18例),用Re-al-time PCR检测AML、CML患者以及髓系造血系统恶性肿瘤细胞系中Twist-1和MPL mRNA的表达情况,并分析其相关性.构建MPL过表达载体,制备慢病毒并感染髓系白血病细胞系K562、U937,通过细胞计数实验、集落形成实验以及药物敏感实验评价其对白血病细胞增殖、集落形成能力以及耐药的影响,并进一步确定Twist-1是否通过MPL发挥白血病促进作用.结果:在U937和K562细胞中过表达Twist-1明显增加MPL蛋白水平(P＜0.05),敲降Twist-1后MPL mRNA的表达水平明显下降(P＜0.01);AML、CML患者骨髓单核细胞(bone marrow mononuclear cells,BMMCs)中Twist-1 mRNA表达与MPL mRNA表达水平呈显著正相关(P＜0.05).过表达MPL使K562和U937细胞对化疗药物柔红霉素及伊马替尼的敏感性显著降低(P＜0.01),且提高K562-MPL、U937-MPL的细胞增殖、集落形成数目(均P＜0.01);干扰Twist-1并过表达MPL显著降低髓系白血病细胞增殖和集落形成(均P＜0.01).结论:Twist-1通过MPL促进AML、CML白血病细胞的增殖、存活和耐药.     

Screening for induction of differentiation and toxicity to blast cells by chemotherapeutic compounds in human myeloid leukemia

Bone marrow cells from 9 patients with acute myeloid leukemia and 1 patient with a blast crisis of chronic myeloid leukemia were cultured to determine their ability to be induced to differentiate by different chemotherapeutic compounds. Five of these 10 patients showed differentiation to granulocytic and/or monocytic cells by culture with medium containing the myeloid cell differentiation-inducing protein MGI-2. Actinomycin D induced differentiation in cells from 2 of the patients who did not show differentiation with MGI-2 containing medium. In these 7 patients there was an increase in the ratio of differentiated myeloid cells to blasts. None of these 10 patients showed induction of differentiation by cytosine arabinoside, adriamycin, or daunomycin, but treatment with these compounds showed in some patients an increase in the ratio of differentiated myeloid cells to blasts. The results indicate that this ratio can be increased by differentiation and also in some patients by toxicity to blast cells. With dexamethasone or vinblastine there was no induction of differentiation and no increase in this ratio in any of the 10 patients tested. After in vivo chemotherapy with low dose cytosine arabinoside, cells from one patient showed a similar response in culture to actinomycin D as cells before chemotherapy, whereas in another patient the cells had acquired the ability to respond to actinomycin D. In contrast, after high-dose in vivo chemotherapy with cytosine arabinoside and daunomycin, cells from a third patient seemed to have lost the ability to differentiate in vitro by MGI-2 containing medium or actinomycin D. The results indicate that pre-screening for differentiation-inducing compounds and compounds that show toxicity to blast cells should be useful to select the appropriate compounds to be used for therapy, and that it is advisable to screen the cells both before and after initiation of therapy.     

CRNDE affects the malignant biological characteristics of human glioma stem cells by negatively regulating miR-186

The long non-coding RNA Colorectal neoplasia differentially expressed (CRNDE) is a novel gene that activated early in colorectal neoplasia, but it is also up-regulated in many other solid tumors. Herein, the function and underlying mechanism of CRNDE in regulating glioma stem cells (GSCs) were investigated. We found that CRNDE expression was up-regulated while miR-186 expression was down-regulated in GSCs. Overexpression of CRNDE could promote the cellular proliferation, migration, invasion and inhibit the apoptosis in GSCs. Overexpression of miR-186 exerted functions of inhibiting the proliferation, migration and invasion of GSCs and promoting apoptosis. And CRNDE decreased the expression levels of XIAP and PAK7 by binding to miR-186 and negatively regulating it. In addition, miR-186 binded to XIAP and PAK7 3′UTR region, and decrease the expression of them, thus regulating the expression levels of downstream target proteins such as caspase 3, BAD, cyclin D1 and MARK2. The in vivo effect of CRNDE and miR-186 showed that the tumor formation rate was minimum in tumor-bearing nude mice with the knockdown of CRNDE and the overexpression of miR-186. In conclusion, CRNDE played an oncogenic role of GSCs through the negative regulation of miR-186. Both CRNDE and miR-186 could be regarded as potential targets in the glioma therapy.     

Bostrycin inhibits proliferation of human lung carcinoma A549 cells via downregulation of the PI3K/Akt pathway

Background

Bostrycin is a novel compound isolated from marine fungi that inhibits proliferation of many cancer cells. However, the inhibitory effect of bostrycin on lung cancers has not been reported. This study is to investigate the inhibitory effects and mechanism of bostrycin on human lung cancer cells in vitro.

Methods

We used MTT assay, flow cytometry, microarray, real time PCR, and Western blotting to detect the effect of bostrycin on A549 human pulmonary adenocarcinoma cells.

Results

We showed a significant inhibition of cell proliferation and induction of apoptosis in bostrycin-treated lung adenocarcinoma cells. Bostrycin treatment caused cell cycle arrest in the G0/G1 phase. We also found the upregulation of microRNA-638 and microRNA-923 in bostrycin-treated cells. further, we found the downregulation of p110α and p-Akt/PKB proteins and increased activity of p27 protein after bostrycin treatment in A549 cells.

Conclusions

Our study indicated that bostrycin had a significant inhibitory effect on proliferation of A549 cells. It is possible that upregulation of microRNA-638 and microRNA-923 and downregulaton of the PI3K/AKT pathway proteins played a role in induction of cell cycle arrest and apoptosis in bostrycin-treated cells.     

The cyclooxygenase-2 inhibitor NS-398 inhibits proliferation and induces apoptosis in human osteosarcoma cells via downregulation of the survivin pathway

Cyclooxygenase-2 (COX-2) is frequently overexpressed in human malignancies and plays a crucial role in tumorigenesis and cancer progression. The present study aimed to investigate the expression and clinical significance of COX-2 and survivin (SUV) in human osteosarcomas (OS), and explore the effects and molecular mechanisms of a selective COX-2 inhibitor NS-398 and SUV on tumor proliferation and apoptosis. Fifty cases of human OS and osteochondromas (OC) were collected. The expression of COX-2 and SUV was assessed using immunohistochemical assays in biopsy samples. MG-63 human OS cells were treated with different concentrations of NS-398, used to investigate their effects on cell proliferation and apoptosis. The recombinant small hairpin RNA adenovirus vector rAd5-SUV was constructed, and the effects and molecular mechanisms of knockdown of SUV on proliferation and apoptosis were evaluated in MG-63 cells. A subcutaneous xenograft tumor model was established, validating the effects of rAd5-SUV on tumor growth in vivo. Based on the results, the expression of COX-2 and SUV in OS showed a higher strong reactivity rate compared with OC (73.3 vs. 25.0%, P=0.001; 63.3 vs. 30.0%, P=0.02), but it did not correlate with the clinicopathological characteristics of OS. NS-398 inhibited proliferation, induced apoptosis and decreased the mRNA expression of COX-2 and SUV in MG-63 cells. Furthermore, adenovirus-mediated knockdown of SUV inhibited proliferation, induced apoptosis, reduced the expression of proliferating cell nuclear antigen (PCNA), increased the expression of caspase-3 (CAS-3) and slowed the growth of xenograft tumors in MG-63 cells. Taken together, the expression of COX-2 and SUV is closely correlated with human OS, and inhibition of COX-2 or knockdown of SUV suppresses tumor proliferation and induces apoptosis, suggesting that COX-2 may be involved in OS cell proliferation and apoptosis through SUV-mediated regulation of PCNA and CAS-3 expression, and provides a potential therapeutic strategy for the treatment of cancer.     

Suppression of proline-directed protein kinase F(A) expression inhibits the growth of human chronic myeloid leukaemia cells

Initial studies revealed that proline-directed protein kinase F(A) (PDPK F(A)) was overexpressed in various cancerous tissues relative to normal controls. However, the functional role of overexpressed PDPK F(A) in cancer remains to be established. In this report, we explore the potential role of PDPK F(A) in leukaemia cell growth by investigating the effects of partial inhibition of this kinase on the malignant phenotype of human chronic myeloid leukaemia cells (K562). Cloning of PDPK F(A) cDNA and its recombinant antisense expression vector and PDPK F(A)-specific antibody were successfully developed. Two stable antisense clones of K562 cells were subcloned which expressed 70% and 45% of PDPK F(A) respectively, compared with control-transfected clone in both immunoprecipitate activity assay and immunoblot analysis. In sharp contrast, these two antisense clones expressed no significant suppression of any other related PDPK family members, indicating the specificity of these two antisense clones. Moreover, these antisense clones proportionally and potentially exhibited cell growth retardation, poor clonogenic growth in soft agar and loss of serum independence. The results demonstrate that specific antisense suppression of PDPK F(A) is sufficient to interfere with the growth of K562 cells, indicating that PDPK F(A) is essential for human chronic myeloid leukaemia cell growth.     

Effects of human fibroblasts from myelometaplasic and non-myelometaplasic hematopoietic tissues on CD34+ stem cells

Fibroblasts demonstrate different phenotypes and functions according to the tissue of origin and its physiopathologic state. We previously showed that fibroblasts isolated in culture from myelometaplasic (MM) spleen differed phenotypically from fibroblasts from normal bone marrow (BM). We compared the influence of each type of fibroblasts on the behavior of CD34+ stem cells. Expansion of nucleated cells was observed when blood CD34+ cells were co-cultured for 3 weeks with MM spleen-derived fibroblasts in monolayers. Myeloid cell differentiation was also observed as indicated by a decline in CD34+ cells and increases in CD14+, CD15+ and CD41+ cells. This myeloid differentiation was enhanced in the presence of MM spleen compared with normal BM-derived fibroblasts. Similarly, proliferation and differentiation of BM CD34+ cells was better in the presence of BM rather than MM spleen-derived fibroblasts. In addition, fibroblasts from MM spleen also induced a differentiation of CD56+ natural killer (NK) cells whereas BM-derived fibroblasts did not. Overall, the data indicate that cultured fibroblasts from diseased tissue have distinct growth and differentiation regulatory characteristics. They also suggest a role for these cells in hematopoietic disorders.