Project description:HOX genes encode a family of homeodomain-containing transcription factors involved in the determination of cell fate and identity during embryonic development. They also behave as oncogenes in some malignancies. In this study, we found high expression of the HOXD9 gene transcript in glioma cell lines and human glioma tissues by quantitative real-time PCR. Using immunocytochemistry, we observed HOXD9 protein expression in human brain tumor tissues, including astrocytomas and glioblastomas. To investigate the role of HOXD9 in gliomas, we silenced its expression in the glioma cell line U87 using HOXD9-specific siRNA, and observed decreased cell proliferation, cell cycle arrest, and induction of apoptosis. It was suggested that HOXD9 contributes to both cell proliferation and/or cell survival. The HOXD9 gene was highly expressed in a side population (SP) of SK-MG-1 cells that was previously identified as an enriched-cell fraction of glioma cancer stem-like cells. HOXD9 siRNA treatment of SK-MG-1 SP cells resulted in reduced cell proliferation. Finally, we cultured human glioma cancer stem cells (GCSCs) from patient specimens found with high expression of HOXD9 in GCSCs compared with normal astrocyte cells and neural stem/progenitor cells (NSPCs). Our results suggest that HOXD9 may be a novel marker of GCSCs and cell proliferation and/or survival factor in gliomas and glioma cancer stem-like cells, and a potential therapeutic target. we analyzed the expression and function of HOXD9 in human gliomas and found high expression of HOXD9 in GCSCs. HOXD9 contributes to cell proliferation and/or survival in glioma cells and glioma cancer stem-like cells.
Project description:Glioblastoma is the most common and most devastating adult primary brain tumor. Despite aggressive multimodal therapy, the median survival is approximately one year after diagnosis. In recent years bone marrow-derived human mesenchymal stem cells (BM-hMSCs) have shown promise as cell-based delivery vehicles for anti-glioma therapeutics. This is largely due to their innate ability to migrate towards gliomas. Several studies have successfully demonstrated their use as delivery vehicles for anti-glioma agents. However, it is now evident that BM-hMSCs demonstrate variable tropism towards gliomas based on a clinically relevant glioma stem cell (GSC) model of GBM. In this study, we compared the proteomic profile of cancer and stromal cell populations in GSC xenografts that attract BM-hMSCs (‘attractors’) with those to do not (‘non-attractors’) in order to identify cell-signaling pathways that may modulate BM-hMSCs homing followed by targeted transcriptomic analysis of human gene sets related to glioma biology. We identified lower protein expression of fatty acid metabolism and glucose-dependent metabolic pathways in attractors. While transcriptomic analysis suggested that N-linked glycosylation was increased. Conversely, glucose metabolic pathways, including oxidative phosphorylation, were increased in the stromal cells present in attractors. The results presented here provide the first evidence for glucose metabolism, reactive oxidative species and lipid-mediated tumor inflammatory response, and N-linked glycosylation in the homing of BM-hMSC to GSC xenografts. Reciprocal expression of these pathways in the stromal cell population may suggest microenvironment cross-talk. Our studies provide new insights on the signaling correlates underlying the differential homing capacity of BM-hMSCs to GSC xenografts.
Project description:HOX genes encode a family of homeodomain-containing transcription factors involved in the determination of cell fate and identity during embryonic development. They also behave as oncogenes in some malignancies. In this study, we found high expression of the HOXD9 gene transcript in glioma cell lines and human glioma tissues by quantitative real-time PCR. Using immunocytochemistry, we observed HOXD9 protein expression in human brain tumor tissues, including astrocytomas and glioblastomas. To investigate the role of HOXD9 in gliomas, we silenced its expression in the glioma cell line U87 using HOXD9-specific siRNA, and observed decreased cell proliferation, cell cycle arrest, and induction of apoptosis. It was suggested that HOXD9 contributes to both cell proliferation and/or cell survival. The HOXD9 gene was highly expressed in a side population (SP) of SK-MG-1 cells that was previously identified as an enriched-cell fraction of glioma cancer stem-like cells. HOXD9 siRNA treatment of SK-MG-1 SP cells resulted in reduced cell proliferation. Finally, we cultured human glioma cancer stem cells (GCSCs) from patient specimens found with high expression of HOXD9 in GCSCs compared with normal astrocyte cells and neural stem/progenitor cells (NSPCs). Our results suggest that HOXD9 may be a novel marker of GCSCs and cell proliferation and/or survival factor in gliomas and glioma cancer stem-like cells, and a potential therapeutic target.
Project description:Stability Analysis of a Mathematical Model for Glioma-Immune Interaction under Optimal Therapy
Subhas Khajanchi
Abstract
We investigate a mathematical model using a system of coupled ordinary differential equations, which describes the interplay of malignant glioma cells, macrophages, glioma specific CD8+T cells and the immunotherapeutic drug Adoptive Cellular Immunotherapy (ACI). To better understand under what circumstances the glioma cells can be eliminated, we employ the theory of optimal control. We investigate the dynamics of the system by observing biologically feasible equilibrium points and their stability analysis before administration of the external therapy ACI. We solve an optimal control problem with an objective functional which minimizes the glioma cell burden as well as the side effects of the treatment. We characterize our optimal control in terms of the solutions to the optimality system, in which the state system coupled with the adjoint system. Our model simulation demonstrates that the strength of treatment u1(t) plays an important role to eliminate the glioma cells. Finally, we derive an optimal treatment strategy and then solve it numerically.
Keywords: malignant gliomas; stability analysis; optimal control; adoptive cellular immunotherapy
Project description:The recent identification of cancer stem cells (CSCs) in multiple human cancers provides a new inroad to understanding tumorigenesis at the cellular level. CSCs are defined by their characteristics of self-renewal, multipotentiality, and tumor initiation upon transplantation. By testing for these defining characteristics, we provide evidence for the existence of CSCs in a transgenic mouse model of glioma, S100ß-verbB;Trp53. In this glioma model, CSCs are enriched in the side-population (SP) cells. These SP cells have enhanced tumor-initiating capacity, self-renewal, and multipotentiality compared to non-SP cells from the same tumors. Furthermore, gene expression analysis comparing FACS-sorted cancer SP cells to non-SP cancer cells and normal neural SP cells identified 45 candidate genes that are differentially expressed in glioma stem cells. We validated the expression of two genes from this list (S100a4 and S100a6) in primary mouse gliomas and human glioma samples. Analyses of xenografted human GBM (glioblatoma multiforme) cell lines and primary human glioma tissues show that S100A4 and S100A6 are expressed in a small subset of cancer cells and that their abundance is positively correlated to tumor grade. In conclusion, this study shows that CSCs exist in a mouse glioma model, suggesting that this model can be used to study the molecular and cellular characteristics of CSCs in vivo and to further test the cancer stem cell hypothesis.
Project description:Most human cancers arise from stem/progenitor cells by sequential accumulation of genetic/epigenetic alterations, while cancer modeling typically requires simultaneous multiple oncogenic events. Here we show that a single p53 mutation, despite causing no defect in mouse brain, promoted neural stem/progenitor cells to spontaneously accumulate oncogenic alterations, including loss of multiple chromosomal (chr) regions syntenic to human chr10 containing Pten, forming malignant gliomas/glioblastomas with PI3K/Akt activation. Rictor/mTORC2 loss inhibited Akt signaling, greatly delaying and reducing glioma formation by suppressing glioma precursors within the subventricular zone stem-cell niche. Unexpectedly, Rictor/mTORC2 loss delayed timely differentiation of granule cell precursors (GCPs) during cerebellar development, promoting sustained GCP proliferation and medulloblastoma formation, which recapitulated critical features of TP53-mutant Sonic Hedgehog (SHH) medulloblastomas with GLI2 and/or N-MYC amplification. Our study demonstrates that Rictor/mTORC2 has opposing functions in neural stem cells and GCPs in the adult and developing brain, promoting malignant gliomas/glioblastoma and suppressing SHH-medulloblastoma formation, respectively.
Project description:B7H3 (also known as CD276) is a co-stimulator checkpoint protein of the cell surface B7 superfamily. Recently, the function beyond immune regulation of B7H3 has been widely studied. However, the expression preference and the regulation mechanism underlying B7H3 in different subtypes of gliomas is rarely understood. We show here that B7H3 expression is significantly decreased in IDH-mutated gliomas and in cultured IDH1-R132H glioma cells. Accumulation of 2-HG leads to a remarkable downregulation of B7H3 protein and the activity of IDH1-R132H mutant is responsible for B7H3 reduction in glioma cells. Inhibition of autophagy by inhibitors like leupeptin, chloroquine (CQ), and Bafilomycin A1 (Baf-A1) blocks the degradation of B7H3 in glioma cells. In the meantime, the autophagy flux is more active with higher LC3B-II and lower p62 in IDH1-R132H glioma cells than in IDH1-WT cells. Furthermore, sequence alignment analysis reveals potential LC3-interacting region (LIR) motifs 'F-V-S/N-I/V' in B7H3. Moreover, B7H3 interacts with p62 and CQ treatment significantly enhances this interaction. Additionally, we find that <i>B7H3</i> is positively correlated with <i>VEGFA</i> and <i>MMP2</i> by bioinformatics analysis in gliomas. B7H3 and VEGFA are decreased in IDH-mutated gliomas and further reduced in 2-HG<sup>high</sup> gliomas compared to 2-HG<sup>low</sup> glioma sections by IHC staining. Our study demonstrates that B7H3 is preferentially overexpressed in IDH wild-type gliomas and could serve as a potential theranostic target for the precise treatment of glioma patients with wild-type IDH.
Project description:High-grade gliomas (HGGs) include the most common and the most aggressive primary brain tumor of adults and children. Despite multimodality treatment, most high grade gliomas eventually recur and are ultimately incurable. Several studies suggest that the initiation, progression, and recurrence of gliomas are driven, at least partly, by cancer stem-like cells. A defining characteristic of these cancer stem-like cells is their capacity to self-renew. We have identified a hypoxia-induced pathway that utilizes the Hypoxia Inducible Factor 1α (HIF-1α) transcription factor and the JAK1/2-STAT3 (Janus Kinase 1/2 - Signal Transducer and Activator of Transcription 3) axis to enhance the self-renewal of glioma stem-like cells. Hypoxia is a commonly found pathologic feature of HGGs. Under hypoxic conditions, HIF-1α levels are greatly increased in glioma stem-like cells. Increased HIF-1α activates the JAK1/2-STAT3 axis and enhances tumor stem-like cell self-renewal. Our data further demonstrate the importance of Vascular Endothelial Growth Factor (VEGF) secretion for this pathway of hypoxia-mediated self-renewal. Brefeldin A and EHT-1864, agents that significantly inhibit VEGF secretion, decreased stem cell self-renewal, inhibited tumor growth, and increased the survival of mice allografted with S100β-v-erbB/p53-/- glioma stem-like cells. These agents also inhibit the expression of a hypoxia gene expression signature that is associated with decreased survival of HGG patients. These findings suggest that targeting the secretion of extracellular, autocrine/paracrine mediators of glioma stem-like cell self-renewal could potentially contribute to the treatment of HGG.
Project description:Glioblastoma (GBM) is the most frequent and malignant brain tumor with an overall survival of only 14.6 months. Although these tumors are treated with surgery, radiation and chemotherapy recurrence is inevitable. A critical population of tumor cells in terms of therapy, the so-called cancer stem cells (CSCs), has been identified in gliomas and many other cancers. These tumor cells have a stem cell-like phenotype and are suggested to be responsible for tumor growth, chemo- and radio-resistance as well as recurrence. However, functional evidence for migrating glioma cells having a stem cell-like phenotype is currently lacking.