A New Approach in Gene Therapy of Glioblastoma Multiforme: Human Olfactory Ensheathing Cells as a Novel Carrier for Suicide Gene Delivery

Fluoxetine enhances the antitumor effect of olfactory ensheathing cell-thymidine kinase/ganciclovir gene therapy in human glioblastoma multiforme cells through upregulation of Connexin43 levels

Glioblastoma multiforme (GBM) is the most invasive form of primary brain astrocytoma, resulting in poor clinical outcomes. Herpes simplex virus thymidine kinase/ganciclovir (HSV-TK/GCV) gene therapy is considered a promising strategy for GBM treatment. Since Connexin43 (Cx43) expression is reduced in GBM cells, increasing Cx43 levels could enhance the effectiveness of gene therapy. The present study aims to examine the impact of fluoxetine on HSV-TK/GCV gene therapy in human GBM cells using human olfactory ensheathing cells (OECs) as vectors. The effect of fluoxetine on Cx43 levels was assessed using the western blot technique. GBM-derived astrocytes and OECs-TK were Cocultured, and the effect of fluoxetine on the Antitumor effect of OEC-TK/GCV gene therapy was evaluated using MTT assay and flow cytometry. Our results showed that fluoxetine increased Cx43 levels in OECs and GBM cells and augmented the killing effect of OECs-TK on GBM cells. Western blot data revealed that fluoxetine enhanced the Bax/Bcl2 ratio and the levels of cleaved caspase-3 in the coculture of OECs-TK and GBM cells. Moreover, flow cytometry data indicated that fluoxetine increased the percentage of apoptotic cells in the coculture system. This study suggests that fluoxetine, by upregulating Cx43 levels, could strengthen the Antitumor effect of OEC-TK/GCV gene therapy on GBM cells.

Current Status of Research on Targeted Therapy Against Central Nervous System Tumors in Low- and Lower-Middle-Income Countries

OBJECTIVE

In recent decades, a significant body of research has focused on targeted therapies for the treatment of central nervous system (CNS) tumors to enhance the effectiveness of management strategies. However, most of these efforts have been centered in high-income countries, which renders the generalizability of their results to low- and middle-income countries questionable. Therefore, in this review, we systematically investigated the status of research conducted on targeted therapy for CNS tumors in low- and lower-middle-income countries to elucidate the contribution of these countries in advancing neuro-oncology.

METHODS

A systematic search of 3 databases was performed using a predefined search strategy. After screening the articles based on our inclusion/exclusion criteria, the data were extracted to a predesigned Excel worksheet.

RESULTS

A review of 44 included studies showed that India, Iran, and Lebanon were the only countries with a contribution to this field. All included studies were laboratory or animal experiments, and there were no clinical studies in this field. The most investigated CNS tumor was malignant glioma, and gene-targeted therapy was the most investigated category of targeted therapies in these countries.

CONCLUSIONS

Low- and lower-middle-income countries comprise more than half of the world population, but they are deprived of targeted therapies against CNS tumors. Although there are basic experiments performed on this subject, they originate in a limited number of these countries. Therefore, targeted therapy is in its preliminary stage in these countries.

β2-Adrenergic receptor agonist enhances the bystander effect of HSV-TK/GCV gene therapy in glioblastoma multiforme via upregulation of connexin 43 expression

Glioblastoma multiforme (GBM) is the most invasive form of primary brain astrocytoma. Gene therapy using the herpes simplex virus thymidine kinase/ganciclovir (HSV-TK/GCV) is a new strategy for GBM treatment. As the connexin 43 (Cx43) levels are downregulated in GBM cells, it seems that the upregulation of Cx43 could improve the efficacy of the gene therapy. This study aims to evaluate the effect of clenbuterol hydrochloride (Cln) as a β2-adrenergic receptor agonist on HSV-TK/GCV gene therapy efficacy in human GBM cells using olfactory ensheathing cells (OECs) as vectors. The lentivirus containing the thymidine kinase gene was transduced to OECs and the effective dose of GCV on cells was measured by MTT assay. We found that Cln upregulated Cx43 expression in human GBM cells and OECs and promoted the cytotoxic effect of GCV on the co-culture cells. Western blot results showed that Cln increased the cleaved caspase-3 expression and the Bax/Bcl2 ratio in the co-culture of GBM cells and OEC-TK. Also, the flow cytometry results revealed that Cln increased apoptosis in the co-culture of GBM cells and OEC-TK cells. This study showed that Cln via upregulation of Cx43 expression could enhance the bystander effect of HSVTK-GCV gene therapy in human GBM cells.

Treatment of Breast Cancer-Bearing BALB/c Mice with Magnetic Hyperthermia using Dendrimer Functionalized Iron-Oxide Nanoparticles

The development of novel nanoparticles for diagnostic and therapeutic applications has been one of the most crucial challenges in cancer theranostics for the last decades. Herein, we functionalized iron oxide nanoparticles (IONPs) with the fourth generation (G₄) of poly amidoamine (PAMAM) dendrimers (G₄@IONPs) for magnetic hyperthermia treatment of breast cancer in Bagg albino strain C (BALB/c)mice. The survival of breast cancer cells significantly decreased after incubation with G₄@IONPs and exposure to an alternating magnetic field (AMF) due to apoptosis and elevation of Bax (Bcl-2 associated X)/Bcl-2(B-cell lymphoma 2) ratio. After intratumoral injection of G₄@IONPs, tumor-bearing BALB/c mice were exposed to AMF for 20 min; this procedure was repeated three times every other day. After the last treatment, tumor size was measured every three days. Histopathological and Immunohistochemical studies were performed on the liver, lung, and tumor tissues in treated and control mice. The results did not show any metastatic cells in the liver and lung tissues in the treatment group, while the control mice tissues contained metastatic breast cancer cells. Furthermore, the findings of the present study showed that magnetic hyperthermia treatment inhibited tumor growth by increasing cancer cell apoptosis, as well as reducing the tumor angiogenesis.

MiR-920 and LSP1 co-regulate the growth and migration of glioblastoma cells by modulation of JAK2/STAT5 pathway

This study probes the function and mechanism of lymphocyte-specific protein 1 (LSP1) in glioblastoma pathogenesis. According to the data acquired from TCGA, Oncomine and GEO databases, the expression and prognostic value of LSP1 and miR-920 in glioblastoma patients were analyzed. The expression levels of LSP1 in U251 and A172 cell lines were analyzed by qRT-PCR and western blotting. CCK8, colony formation and transwell assays were utilized to test glioblastoma cell malignant abilities. Furthermore, the associations between LSP1 and miR-920 were indentified by bioinformatics analysis and rescue assays. Moreover, the protein expression levels of p-JAK2, JAK2, p-STAT5 and STAT5, as the hallmark of JAK/STAT5 signaling, were detected by western blotting. The observations showed that LSP1 was highly augmented in glioblastoma samples. Additionally, up-regulation of LSP1 was associated with a unfavorable prognosis in glioblastoma patients. Biological experiments revealed that depletion of LSP1 significantly suppressed the proliferation, invasion and migration of U251 and A172 cells. MiR-920, as an upstream regulator of LSP1, negatively modulated LSP1 expression and promoted U251 cells malignant behaviors after miR-920 inhibitor treatment. However, together knockdown LSP1 and miR-920 inhibited these effects. Moreover, the expression levels of p-JAK2 and p-STAT5 were increased or decreased in U251 cells after transfection of miR-920 inhibitor or si-LPS1. Taken together, miR-920 might blocked the malignant development of glioblastoma cells, which is possibly realized by targeting LSP1 and modulation of JAK/STAT5 pathway. These findings implied that miR-920/LSP1 was a potential therapeutic target for glioblastoma treatment.

β2-Adrenergic Receptor Stimulation Upregulates Cx43 Expression on Glioblastoma Multiforme and Olfactory Ensheathing Cells

Glioblastoma multiforme (GBM) is described as an invasive astrocytic tumor in adults. Despite current standard treatment approaches, the outcome of GBM remains unfavorable. The downregulation of connexin 43 (Cx43) expression is one of the molecular transformations in GBM cells. The Cx43 levels and subsequently gap junctional intercellular communication (GJIC) have an important role in the efficient transfer of cytotoxic drugs to whole tumor cells. As shown in our previous study, the stimulation of the β2-adrenergic receptor (β2-AR) leads to the modulation of Cx43 expression level in the GBM cell line. Here we further examine the effect of clenbuterol hydrochloride as a selective β2-AR agonist on the Cx43 expression in human GBM-derived astrocyte cells and human olfactory ensheathing cells (OECs) as a potent vector for future gene therapy. In this experiment, first we established a primary culture of astrocytes from GBM samples and verified the purity using immunocytofluorescent staining. Western blot analysis was performed to evaluate the Cx43 protein level. Our western blot findings reveal that clenbuterol hydrochloride upregulates the Cx43 protein level in both primary human astrocyte cells and human OECs. Conversely, ICI 118551 as a β2-AR antagonist inhibits these effects. Moreover, clenbuterol hydrochloride increases the Cx43 expression in primary human astrocyte cells and OECs co-culture systems, and ICI 118551 reverses these effects. To confirm the western blot results, immunocytofluorescent staining was performed to evaluate the β2-AR agonist effect on Cx43 expression. Our immunocytofluorescent results supported western blot analysis in primary human astrocyte cells and the OECs co-culture system. The results of this study suggest that the activation of β2-AR with regard to Cx43 protein levels enhancement in GBM cells and OECs might be a promising approach for GBM treatment in the future.

Olfactory Ensheathing Cells: A Trojan Horse for Glioma Gene Therapy

BACKGROUND

The olfactory ensheathing cells (OECs) migrate from the peripheral nervous system to the central nervous system (CNS), a critical process for the development of the olfactory system and axonal extension after injury in neural regeneration. Because of their ability to migrate to the injury site and anti-inflammatory properties, OECs were tested against different neurological pathologies, but were never studied in the context of cancer. Here, we evaluated OEC tropism to gliomas and their potential as a "Trojan horse" to deliver therapeutic transgenes through the nasal pathway, their natural route to CNS.

METHODS

OECs were purified from the mouse olfactory bulb and engineered to express a fusion protein between cytosine deaminase and uracil phosphoribosyltransferase (CU), which convert the prodrug 5-fluorocytosine (5-FC) into cytotoxic metabolite 5-fluorouracil, leading to a bystander killing of tumor cells. These cells were injected into the nasal cavity of mice bearing glioblastoma tumors and OEC-mediated gene therapy was monitored by bioluminescence imaging and confirmed with survival and ex vivo histological analysis. All statistical tests were two-sided.

RESULTS

OECs migrated from the nasal pathway to the primary glioma site, tracked infiltrative glioma stemlike cells, and delivered therapeutic transgene, leading to a slower tumor growth and increased mice survival. At day 28, bioluminescence imaging revealed that mice treated with a single injection of OEC-expressing CU and 5-FC had tumor-associated photons (mean [SD]) of 1.08E + 08 [9.7E + 07] vs 4.1E + 08 [2.3E + 08] for control group (P < .001), with a median survival of 41 days vs 34 days, respectively (ratio = 0.8293, 95% confidence interval = 0.4323 to 1.226, P <  .001) (n = 9 mice per group).

CONCLUSIONS

We show for the first time that autologous transplantation of OECs can target and deliver therapeutic transgenes to brain tumors upon intranasal delivery, the natural route of OECs to the CNS, which could be extended to other types of cancer.

Down-regulation of 14-3-3 zeta sensitizes human glioblastoma cells to apoptosis induction

Strong 14-3-3 zeta protein expression plays an important role in tumorigenesis, including in the maintenance of cell growth, resistance increase, and the prevention of apoptosis. In this study, we focus on two targets: (1) the expression of 14-3-3 zeta in the different grades of human astrocytoma (II-IV), (2) suppression of 14-3-3 zeta protein expression in glioblastoma derived astrocytes by 14-3-3 zeta shRNA lentiviral particles. The tissues of human astrocytoma were provided from 30 patients (ten of each grade of astrocytoma). Control tissues were obtained from the peritumoral brain zone of those patients with glioblastoma. The protein and mRNA expression levels of each astrocytoma grade were assessed via western blotting and RT-PCR, respectively. Results indicated that 14-3-3 zeta was significantly expressed in glioblastoma multiforme (grade IV) and 14-3-3 zeta expression levels enhanced according to the increase of astrocytoma malignancy. In the cellular study for knock down of the 14-3-3 zeta protein, surgical biopsy of glioblastoma was used to isolate primary astrocyte. Astrocytes were transduced with 14-3-3 zeta shRNA or non-targeted shRNA lentiviral particles. Furthermore, reduction of the 14-3-3 zeta protein expression in the astrocytes evaluated through qRT-PCR and western blot after transduction of 14-3-3 zeta shRNA lentiviral particles. Moreover, apoptosis properties, including DNA fragmentation and ratio increase of Bax/Bcl-2 were observed in astrocytes following reduction of 14-3-3 zeta protein expression. Further observation indicated that the mitochondrial pathway through release of cytochorome c and caspase-3 activity was involved in the apoptosis induction. Hence, this study demonstrates a key role of the 14-3-3 zeta protein in tumorigenesis but also indicates that 14-3-3 zeta can be considered as a target for the astrocytoma treatment specially glioblastoma.

Lentiviral Vectors as Tools for the Study and Treatment of Glioblastoma

Glioblastoma (GBM) has the worst prognosis among brain tumors, hence basic biology, preclinical, and clinical studies are necessary to design effective strategies to defeat this disease. Gene transfer vectors derived from the most-studied lentivirus-the Human Immunodeficiency Virus type 1-have wide application in dissecting GBM specific features to identify potential therapeutic targets. Last-generation lentiviruses (LV), highly improved in safety profile and gene transfer capacity, are also largely employed as delivery systems of therapeutic molecules to be employed in gene therapy (GT) approaches. LV were initially used in GT protocols aimed at the expression of suicide factors to induce GBM cell death. Subsequently, LV were adopted to either express small noncoding RNAs to affect different aspects of GBM biology or to overcome the resistance to both chemo- and radiotherapy that easily develop in this tumor after initial therapy. Newer frontiers include adoption of LV for engineering T cells to express chimeric antigen receptors recognizing specific GBM antigens, or for transducing specific cell types that, due to their biological properties, can function as carriers of therapeutic molecules to the cancer mass. Finally, LV allow the setting up of improved animal models crucial for the validation of GBM specific therapies.

Tumoricidal effect of human olfactory ensheathing cell mediated suicide gene therapy in human glioblastoma cells

The potential of herpes simplex virus type 1 thymidine kinase (HSV-tk)-expressing olfactory ensheathing cells (OEC) treated with ganciclovir (GCV) to induce cell death in adjacent HSV-tk-negative cells (bystander effect) has been well demonstrated. Although it has been shown that bystander effect occurs through the delivery of phosphorylated GCV, the bystander effect mechanism and the role of gap junctions for human OECs mediated suicide gene therapy in primary astrocytes of human glioblastma remain obscure. In the present study, the efficacy of a new method for the transfer of phosphorylated GCV from OECs into primary astrocytes was evaluated. Surgical biopsy of glioblastoma was used to isolate primary astrocyte. Biopsy of olfactory mucosa was applied to isolate olfactory ensheathing cell. Expression of S100-beta antigen was confirmed immunocytochemically in astrocytes and OECs. OECs were transduced to lentiviral containing thymidine kinase gene (TK) and co-cultured with astrocytes. Fluorescent dye transfer and western blot analysis indicated the expression of connexin43 between olfactory ensheathing cells and astrocytes whereas, expression of the gap junction protein connexin43 was inhibited by the gap junction inhibitor 18α-glycyrrhethinic acid (AGA, 20 µg/ml). Furthermore, co-culture of astrocytes with OEC-TK in the presence of concentration of 30 µg/ml GCV led to a decrease in astrocytes survival rate. Also, apoptosis hallmarks, including DNA fragmentation in cell nuclear, expression increase of Bax to Bcl-2 ratio and increase of caspase3 activation were observed in this study. Our findings suggest that human olfactory ensheathing cells can deliver phosphorylated GCV into the glioblastoma derived astrocytes through gap junction communication for apoptosis induction.

Stable Knockdown of Adenosine Kinase by Lentiviral Anti-ADK miR-shRNAs in Wharton's Jelly Stem Cells

Objective

In this study, we describe an efficient approach for stable knockdown of adenosine kinase (ADK) using lentiviral system, in an astrocytoma cell line and in human Wharton’s jelly mesenchymal stem cells (hWJMSCs). These sources of stem cells besides having multilineage differentiation potential and immunomodulatory activities, are easily available in unlimited numbers, do not raise ethical concerns and are attractive for gene manipulation and cell-based gene therapy.

Materials and Methods

In this experimental study, we targeted adenosine kinase mRNA at 3' and performed coding sequences using eight miR-based expressing cassettes of anti-ADK short hairpin RNA (shRNAs). First, these cassettes with scrambled control sequences were cloned into expressing lentiviral pGIPZ vector. Quantitative real time-polymerase chain reaction (qRT-PCR) was used to screen multi-cassettes anti-ADK miR-shRNAs in stably transduced U-251 MG cell line and measuring ADK gene expression at mRNA level. Extracted WJMSCs were characterized using flow cytometry for expressing mesenchymal specific marker (CD44+) and lack of expression of hematopoietic lineage marker (CD45-). Then, the lentiviral vector that expressed the most efficient anti-ADK miR-shRNA, was employed to stably transduce WJMSCs.

Results

Transfection of anti-ADK miR-shRNAs in HEK293T cells using CaPO₄ method showed high efficiency. We successfully transduced U-251 cell line by recombinant lentiviruses and screened eight cassettes of anti-ADK miR- shRNAs in stably transduced U-251 MG cell line by qRT-PCR. RNAi-mediated down-regulation of ADK by lentiviral system indicated up to 95% down-regulation of ADK. Following lentiviral transduction of WJMSCs with anti-ADK miR- shRNA expression cassette, we also implicated, down-regulation of ADK up to 95% by qRT-PCR and confirmed it by western blot analysis at the protein level.

Conclusion

Our findings indicate efficient usage of shRNA cassette for ADK knockdown. Engineered WJMSCs with genome editing methods like CRISPR/cas9 or more safe viral systems such as adeno-associated vectors (AAV) might be an attractive source in cell-based gene therapy and may have therapeutic potential for epilepsy.

Multiple Sclerosis Gene Therapy with Recombinant Viral Vectors: Overexpression of IL-4, Leukemia Inhibitory Factor, and IL-10 in Wharton's Jelly Stem Cells Used in EAE Mice Model

OBJECTIVES

Immunotherapy and gene therapy play important roles in modern medicine. The aim of this study is to evaluate the overexpression of interleukin-4 (IL-4), IL-10 and leukemia inhibitory factor (LIF) in Wharton's jelly stem cells (WJSCs) in the experimental autoimmune encephalomyelitis (EAE) mice model.

MATERIALS AND METHODS

In this experimental study, a DNA construction containing IL- 4, IL-10 and LIF was assembled to make a polycistronic vector (as the transfer vector). Transfer and control vectors were co-transfected into Human Embryonic Kidney 293 (HEK-293T) cells with helper plasmids which produced recombinant lentiviral viruses (rLV). WJSCs were transduced with rLV to make recombinant WJSC (rWJSC). In vitro protein and mRNA overexpression of IL-4, LIF, and IL-10 were evaluated using quantitative polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay (ELISA) and western blot (WB) analysis. EAE was induced in mice by MOG-CFA and pertussis toxin. EAE mice were injected twice with 2×105 rWJSCs. The in vivo level of IL-4, LIF, IL-10 cytokines and IL-17 were measured by ELISA. Brain tissues were analyzed histologically for evaluation of EAE lesions.

RESULTS

Isolated WJSCs were performed to characterize by in vitro differentiation and surface markers were analyzed by flow cytometry method. Cloning of a single lentiviral vector with five genes was done successfully. Transfection of transfer and control vectors were processed based on CaPO4 method with >90% efficiency. Recombinant viruses were produced and results of titration showed 2-3×107 infection-unit/ml. WJSCs were transduced using recombinant viruses. IL-4, IL-10 and LIF overexpression were confirmed by ELISA, WB and qPCR. The EAE mice treated with rWJSC showed reduction of Il-17, and brain lesions as well as brain cellular infiltration, in vivo. Weights and physical activity were improved in gene-treated group.

CONCLUSIONS

These results showed that gene therapy using anti-inflammatory cytokines can be a promising approach against multiple sclerosis (MS). In addition, considering the immunomodulatory potential of WJSCs, an approach using a combination of WJSCs and gene therapy will enhance the treatment efficacy.

Primary Olfactory Ensheathing Cell Culture from Human Olfactory Mucosa Specimen

The human olfactory mucosa is located in the middle and superior turbinates, and the septum of nasal cavity. Olfactory mucosa plays an important role in detection of odours and it is also the only nervous tissue that is exposed to the external environment. This property leads to easy access to the olfactory mucosa for achieving various researches. The lamina propria of olfactory mucosa consists of olfactory ensheathing cells (OECs) that cover the nerve fibers of olfactory. Here we describe a protocol for isolation of OECs from biopsy of human olfactory mucosa.

Preparation of Primary Astrocyte Culture Derived from Human Glioblastoma Multiforme Specimen

Glioblastoma multiforme (GBM) is a grade 4 astrocytoma tumor in central nervous system. Astrocytes can be isolated from human GBM. Study of astrocytes can provide insights about the formation, progression and recurrence of glioblastoma. For using isolated astrocytes, new studies can be designed in the fields of pharmacology, neuroscience and neurosurgery for glioblastoma treatment. This protocol describes the details for preparing high purity primary astrocytes from human GBM. Tumor tissue is disrupted using mechanical dissociation and chemical digestion in this protocol. 2 weeks after plating the cell suspension in culture, primary astrocytes are available for further subculturing and immunocytochemistry of S100-beta antigen.