SHP2 regulates proliferation and tumorigenicity of glioma stem cells

Forty years ago, adjuvant treatment of patients with GBM using fractionated radiotherapy following surgery was shown to substantially improve survival compared to surgery alone. However, even with the addition of temozolomide to radiotherapy, overall survival is quite limited and local failure remains a fundamental problem, despite multiple attempts to increase dose to the tumor target. This review presents the historical background and clinical rationale leading to the current standard of care consisting of 60 Gy total dose in 2 Gy fractions to the MRI-defined targets in younger, high performance status patients and more hypofractionated regimens in elderly and/or debilitated patients. Particle therapies offer the potential to increase local control while reducing dose and, potentially, long-term neurocognitive toxicity. However, improvements in systemic therapies for GBM will need to be implemented before the full benefits of improved local control can be realized.     

骨髓间充质干细胞表达外源性IL-12对胶质瘤C6细胞增殖的影响

目的:探讨以骨髓间充质干细胞（mesenchymal stem cells,MSCs） 为基因治疗载体表达外源性IL12对胶质瘤C6细胞增殖的影响。方法：分离培养大鼠MSCs, 腺病毒介导IL12基因转染大鼠MSCs(AdIL12MSCs),RTPCR 及Western Blotting检测AdIL12MSCs中IL12基因mRNA及蛋白表达。MTT法检测AdIL12MSCs分泌的外源性IL12对C6胶质瘤细胞增殖活性 的影响,光镜下观察外源性IL12对C6细胞形态的影响。结果：腺病毒介导IL12基因成功转染MSCs形成AdIL12MSC,其IL12基因在mRNA及蛋白水平均有明显表达。AdIL12MSC分泌的外源性IL12显著抑制胶质瘤C6细胞的增殖（P<0.05）。结论：转染IL12的MSCs(AdIL12MSC)能够在mRNA及蛋白水平表达外源性IL12基因,显著抑制胶质瘤C6细胞的增殖。     

骨髓间充质干细胞表达外源性IL-12对胶质瘤C6细胞增殖的影响

目的: 探讨以骨髓间充质干细胞(mesenchymal stem cells,MSCs) 为基因治疗载体表达外源性IL-12对胶质瘤C6细胞增殖的影响.方法:分离培养大鼠MSCs, 腺病毒介导IL-12基因转染大鼠MSCs(AdIL-12-MSCs),RT-PCR 及Western Blotting检测AdIL-12-MSCs中IL-12基因mRNA及蛋白表达.MTT法检测AdIL-12-MSCs分泌的外源性IL-12对C6胶质瘤细胞增殖活性的影响,光镜下观察外源性IL-12对C6细胞形态的影响.结果:腺病毒介导IL-12基因成功转染MSCs形成AdIL-12-MSC,其IL-12基因在mRNA及蛋白水平均有明显表达.AdIL-12-MSC分泌的外源性IL-12显著抑制胶质瘤C6细胞的增殖(P<0.05).结论:转染IL-12的MSCs(AdIL-12-MSC)能够在mRNA及蛋白水平表达外源性IL-12基因,显著抑制胶质瘤C6细胞的增殖.     

Tumor associated mesenchymal stem cells protects ovarian cancer cells from hyperthermia through CXCL12

Hyperthermic intraperitoneal chemotherapy (HIPEC) has shown promise in treatment of ovarian carcinosis. Despite its efficiency for the treatment of peritoneal carcinosis from digestive tract neoplasia, it has failed to demonstrate significant benefit in ovarian cancers. It is therefore essential to understand the mechanism underlying resistance to HIPEC in ovarian cancers. Mesenchymal stem cells (MSC) play an important role in the development of ovarian cancer metastasis and resistance to treatments. A recent study suggests that MSCs may be cytotoxic for cancer cells upon heat shock. In contrast, we describe the protective role of MSC against hyperthermia. Using cytokine arrays we determined that the tumor associated MSC (TAMC) secrete pro‐tumoral cytokines. We studied the effect of hyperthermia in co‐culture setting of TAMC or BM‐MCS associated with ovarian cancer cell lines (SKOV3 and CaOV3) with polyvariate flow cytometry. We demonstrate that hyperthermia does not challenge survival of TAMC or bone marrow derived MSC (BM‐MSC). Both TAMC and BM‐MSC displayed strong protective effect inducing thermotolerance in ovarian cancer cells (OCC). Transwell experiments demonstrated the role of secreted factors. We showed that CXCL12 was inducing thermotolerance and that inhibition of CXCL12/CXCR4 interaction restored cytotoxicity of hyperthermia in co‐culture experiments. Contrary to the previous published study we demonstrated that TAMC and BM‐MSC co‐cultured with OCC induced thermotolerance in a CXCL12 dependant manner. Targeting the interaction between stromal and cancer cells through CXCL12 inhibition might restore hyperthermia sensitivity in ovarian cancers, and thus improve HIPEC efficiency.     

Mesenchymal stem cells deliver synthetic microRNA mimics to glioma cells and glioma stem cells and inhibit their cell migration and self-renewal

MicroRNAs (miRNAs) have emerged as potential cancer therapeutics; however, their clinical use is hindered by lack of effective delivery mechanisms to tumor sites. Mesenchymal stem cells (MSCs) have been shown to migrate to experimental glioma and to exert anti-tumor effects by delivering cytotoxic compounds. Here, we examined the ability of MSCs derived from bone marrow, adipose tissue, placenta and umbilical cord to deliver synthetic miRNA mimics to glioma cells and glioma stem cells (GSCs). We examined the delivery of miR-124 and miR-145 mimics as glioma cells and GSCs express very low levels of these miRNAs. Using fluorescently labeled miRNA mimics and in situ hybridization, we demonstrated that all the MSCs examined delivered miR-124 and miR-145 mimics to co-cultured glioma cells and GSCs via gap junction–dependent and independent processes. The delivered miR-124 and miR-145 mimics significantly decreased the luciferase activity of their respected reporter target genes, SCP-1 and Sox2, and decreased the migration of glioma cells and the self-renewal of GSCs. Moreover, MSCs delivered Cy3-miR-124 mimic to glioma xenografts when administered intracranially. These results suggest that MSCs can deliver synthetic exogenous miRNA mimics to glioma cells and GSCs and may provide an efficient route of therapeutic miRNA delivery in vivo.     

Wnt信号调控胶质瘤或胶质瘤干细胞增殖及迁移作用的研究进展

近年研究发现Wnt信号通路与神经胶质瘤及其肿瘤干细胞的细胞增殖及细胞迁移相关,Wnt信号蛋白及其关键家族成员的表达水平与胶质瘤恶性程度密切有关,提示Wnt信号及相关通路的靶干预可能成为恶性胶质瘤治疗的新途径.     

Tumor-derived CXCL8 signaling augments stroma-derived CCL2-promoted proliferation and CXCL12-mediated invasion of PTEN-deficient prostate cancer cells

Impaired PTEN function is a genetic hallmark of aggressive prostate cancers (CaP) and is associated with increased CXCL8 expression and signaling. The current aim was to further characterize biological responses and mechanisms underpinning CXCL8-promoted progression of PTEN-depleted prostate cancer, focusing on characterizing the potential interplay between CXCL8 and other disease-promoting chemokines resident within the prostate tumor microenvironment. Autocrine CXCL8-stimulation (i) increased expression of CXCR1 and CXCR2 in PTEN-deficient CaP cells suggesting a self-potentiating signaling axis and (ii) induced expression of CXCR4 and CCR2 in PTEN-wild-type and PTEN-depleted CaP cells. In contrast, paracrine CXCL8 signaling induced expression and secretion of the chemokines CCL2 and CXCL12 from prostate stromal WPMY-1 fibroblasts and monocytic macrophage-like THP-1 cells. In vitro studies demonstrated functional co-operation of tumor-derived CXCL8 with stromal-derived chemokines. CXCL12-induced migration of PC3 cells and CCL2-induced proliferation of prostate cancer cells were dependent upon intrinsic CXCL8 signaling within the prostate cancer cells. For example, in co-culture experiments, CXCL12/CXCR4 signaling but not CCL2/CCR2 signaling supported fibroblast-mediated migration of PC3 cells while CXCL12/CXCR4 and CCL2/CCR2 signaling underpinned monocyte-enhanced migration of PC3 cells. Combined inhibition of both CXCL8 and CXCL12 signaling was more effective in inhibiting fibroblast-promoted cell motility while repression of CXCL8 attenuated CCL2-promoted proliferation of prostate cancer cells. We conclude that tumor-derived CXCL8 signaling from PTEN-deficient tumor cells increases the sensitivity and responsiveness of CaP cells to stromal chemokines by concurrently upregulating receptor expression in cancer cells and inducing stromal chemokine synthesis. Combined chemokine targeting may be required to inhibit their multi-faceted actions in promoting the invasion and proliferation of aggressive CaP.     

BMPing off glioma stem cells

Brain tumor stem cells (BTSC) bear some similarities to neural stem cells (NSC). Bone morphogenetic proteins (BMPs) have a proproliferative effect on early embryonic NSC, and a prodifferentiative effect on postnatal NSC. In this issue of Cancer Cell, Lee et al. demonstrate that BMPs have differing effects on different BTSC lines, either promoting or inhibiting an astrocytic-like differentiation program. This latter effect is the result of epigenetic silencing of the BMP receptor 1B (BMPR1B). These findings document the importance of the BMP signaling system in BTSC as well as that of taking heterogeneity into account when studying BTSC as potential targets for therapy.     

Characteristics of glioma stem cells

The cancer stem cell theory postulates that tumors are sustained by a select cell population with specific features, such as self-renewal ability and the capacity to give rise to a heterogeneous mass of tumor cells. The existence of such cells has been demonstrated for glioblastoma, with these cells being referred to as glioma stem cells (GSCs). Glioblastomas are notoriously heterogeneous tumors, however, and the isolation and characterization of their stem cells will require further investigations. Furthermore, the lack of unequivocal markers for GSCs and a partial overlap in characteristics with other cells often lead to confusion. Here, we review the characteristics necessary for a glioma cell to be considered a stem cell, and we adopt our murine glioblastoma model based on genetically modified neural stem cells to illustrate and discuss the GSC concept.     

Bone morphogenetic protein 4 inhibits cell proliferation and induces apoptosis in glioma stem cells

Glioma stem cells (GSCs), which are originated from transformed neural stem cells, are tumor-initiating cells of glioma, the most common primary malignant neoplasm of the central nervous system. Extensive studies have shown that bone morphogenetic protein 4 (BMP4) plays an important role in the differentiation and proliferation of neural stem cells. To seek the functions and mechanisms of BMP4 in GSCs, GSCs isolated from U87 human glioma cells by using vincristine were exposed to BMP4 protein. This study shows that BMP4 inhibited U87 GSC proliferation (p?相似文献   

Frontiers in targeting glioma stem cells

Patients with glioblastoma multiforme (GBM - WHO grade IV) seldom recover. This is due to the infiltrative nature of these tumours and the presence of cellular populations with ability to escape therapies and drive tumour recurrence and progression. In some cases, these resistant cells exhibit stem properties [glioma stem cells (GSC)]. This article aims at discussing relevant issues on GSC resistance to current therapies and outlines possible and promising avenues in regard to novel therapeutic strategies, such as pharmacological, immunological and viral interventions.     

Virotherapy against malignant glioma stem cells

Glioblastoma multiforme, the most common primary intracranial malignancy, is associated with very poor outcome despite advances in surgical techniques and chemo- and radiation therapy. Many novel treatment modalities are being investigated with varying amount of success. Evolution of cancer stem cell hypothesis provides a new venue for developmental therapeutics. In this review, we highlight the literature regarding the existence of glioma stem cells and their characteristics. We also discuss the potential for virotherapy, a novel therapeutic approach utilizing conditionally replicative viruses, to directly target this population of self-renewing cancer stem cells.     

Adult mouse subventricular zones stimulate glioblastoma stem cells specific invasion through CXCL12/CXCR4 signaling

Background

Patients with glioblastoma multiforme (GBM) have an overall median survival of 15 months. This catastrophic survival rate is the consequence of systematic relapses that could arise from remaining glioblastoma stem cells (GSCs) left behind after surgery. We previously demonstrated that GSCs are able to escape the tumor mass and specifically colonize the adult subventricular zones (SVZs) after transplantation. This specific localization, away from the initial injection site, therefore represents a high-quality model of a clinical obstacle to therapy and relapses because GSCs notably retain the ability to form secondary tumors.

Method

In this work, we questioned the role of the CXCL12/CXCR4 signaling in the GSC-specific invasion of the SVZs.

Results

We demonstrated that both receptor and ligand are respectively expressed by different GBM cell populations and by the SVZ itself. In vitro migration bio-assays highlighted that human U87MG GSCs isolated from the SVZs (U87MG-SVZ) display stronger migratory abilities in response to recombinant CXCL12 and/or SVZ-conditioned medium (SVZ-CM) compared with cancer cells isolated from the tumor mass (U87MG-TM). Moreover, in vitro inhibition of the CXCR4 signaling significantly decreased the U87MG-SVZ cell migration in response to the SVZ-CM. Very interestingly, treating U87MG-xenografted mice with daily doses of AMD3100, a specific CXCR4 antagonist, prevented the specific invasion of the SVZ. Another in vivo experiment, using CXCR4-invalidated GBM cells, displayed similar results.

Conclusion

Taken together, these data demonstrate the significant role of the CXCL12/CXCR4 signaling in this original model of brain cancer invasion.     

MET signaling regulates glioblastoma stem cells

Glioblastomas multiforme (GBM) contain highly tumorigenic, self-renewing populations of stem/initiating cells [glioblastoma stem cells (GSC)] that contribute to tumor propagation and treatment resistance. However, our knowledge of the specific signaling pathways that regulate GSCs is limited. The MET tyrosine kinase is known to stimulate the survival, proliferation, and invasion of various cancers including GBM. Here, we identified a distinct fraction of cells expressing a high level of MET in human primary GBM specimens that were preferentially localized in perivascular regions of human GBM biopsy tissues and were found to be highly clonogenic, tumorigenic, and resistant to radiation. Inhibition of MET signaling in GSCs disrupted tumor growth and invasiveness both in vitro and in vivo, suggesting that MET activation is required for GSCs. Together, our findings indicate that MET activation in GBM is a functional requisite for the cancer stem cell phenotype and a promising therapeutic target.     

The use of interleukin 12-secreting neural stem cells for the treatment of intracranial glioma

Neural stem cells (NSCs) are capable of tracking migrating glioma cells. To exploit this tropism to generate an antitumor T-cell response, particularly against disseminating tumor pockets, we inoculated intracranial glioma-bearing mice with interleukin 12 (IL-12) producing NSCs. Intratumoral therapy with IL-12-secreting NSCs prolonged survival compared to treatment with nonsecretory NSCs or saline. NSCs demonstrated strong tropism for disseminating glioma, and IL-12-secreting NSC therapy was associated with enhanced T-cell infiltration in tumor microsatellites and long-term antitumor immunity. These results indicate that the use of tumor tracking NSCs represents a potent new therapeutic modality for glioma.     

胶质瘤干细胞的分子靶向治疗

胶质瘤干细胞（GSC）被认为是恶性胶质瘤迁移、复发和放化疗抵抗的根源。结合分子靶向药物在其他肿瘤领域走向临床的背景，针对 GSC 的分子靶向药物有望取得成功。目前，相关研究主要集中在 Hedgehog、PI3K 等通路，代表药物主要有环巴胺及其衍生物、雷帕霉素及其衍生物，经典药物三氧化二砷、二甲双胍也有抗 GSC 作用。     

雷公藤单体体外抑制胶质瘤细胞的实验研究

背景与目的：已有研究发现雷公藤具有抗肿瘤作用,本研究旨在探讨雷公藤单体对胶质瘤细胞的体外抑制作用。方法：通过MTT法测定3种雷公藤单体（甲素,红素和WilforolA)对胶质瘤细胞株SHG44,C6,U251的体外抑制作用;应用免疫组化法观察雷公藤甲素与雷公藤红素对SHG44胶质瘤细胞中Bax,Bcl-2蛋白表达的影响。结果：雷公藤二萜类单体雷公藤甲素对胶质瘤细胞有极显著的抑制作用;雷公藤三萜类单体中红素的抑制作用次之,两者均使SHG44细胞Bax表达增加,Bcl-2表达下降。结论：雷公藤甲素与雷公藤红素对胶质瘤细胞有明显的抗肿瘤作用,其作用与促进Bax表达,抑制Bcl-2表达,导致细胞凋亡有关。