Rapid and Efficient Invasion Assay of Glioblastoma in Human Brain Organoids

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Human mesenchymal stromal cells inhibit tumor growth in orthotopic glioblastoma xenografts

Background: Mesenchymal stem/stromal cells (MSCs) represent an attractive tool for cell-based cancer therapy mainly because of their ability to migrate to tumors and to release bioactive molecules. However, the impact of MSCs on tumor growth has not been fully established. We previously demonstrated that murine MSCs show a strong tropism towards glioblastoma (GBM) brain xenografts and that these cells are able to uptake and release the chemotherapeutic drug paclitaxel (PTX), maintaining their tropism towards the tumor. Here, we address the therapy-relevant issue of using MSCs from human donors (hMSCs) for local or systemic administration in orthotopic GBM models, including xenografts of patient-derived glioma stem cells (GSCs). Methods: U87MG or GSC1 cells expressing the green fluorescent protein (GFP) were grafted onto the striatum of immunosuppressed rats. Adipose hMSCs (Ad-hMSCs), fluorescently labeled with the mCherry protein, were inoculated adjacent to or into the tumor. In rats bearing U87MG xenografts, systemic injections of Ad-hMSCs or bone marrow (BM)-hMSCs were done via the femoral vein or carotid artery. In each experiment, either PTX-loaded or unloaded hMSCs were used. To characterize the effects of hMSCs on tumor growth, we analyzed survival, tumor volume, tumor cell proliferation, and microvascular density. Results: Overall, the AD-hMSCs showed remarkable tropism towards the tumor. Intracerebral injection of Ad-hMSCs significantly improved the survival of rats with U87MG xenografts. This effect was associated with a reduction in tumor growth, tumor cell proliferation, and microvascular density. In GSC1 xenografts, intratumoral injection of Ad-hMSCs depleted the tumor cell population and induced migration of resident microglial cells. Overall, PTX loading did not significantly enhance the antitumor potential of hMSCs. Systemically injected Ad- and BM-hMSCs homed to tumor xenografts. The efficiency of hMSC homing ranged between 0.02 and 0.5% of the injected cells, depending both on the route of cell injection and on the source from which the hMSCs were derived. Importantly, systemically injected PTX-loaded hMSCs that homed to the xenograft induced cytotoxic damage to the surrounding tumor cells. Conclusions: hMSCs have a therapeutic potential in GBM brain xenografts which is also expressed against the GSC population. In this context, PTX loading of hMSCs seems to play a minor role

Glioblastoma endothelium drives bevacizumab-induced infiltrative growth via modulation of PLXDC1

Bevacizumab, a VEGF-targeting monoclonal antibody, may trigger an infiltrative growth pattern in glioblastoma. We investigated this pattern using both a human specimen and rat models. In the human specimen, a substantial fraction of infiltrating tumor cells were located along perivascular spaces in close relationship with endothelial cells. Brain xenografts of U87MG cells treated with bevacizumab were smaller than controls (p = 0.0055; Student t-test), however, bands of tumor cells spread through the brain farther than controls (p < 0.001; Student t-test). Infiltrating tumor Cells exhibited tropism for vascular structures and propensity to form tubules and niches with endothelial cells. Molecularly, bevacizumab triggered an epithelial to mesenchymal transition with over-expression of the receptor Plexin Domain Containing 1 (PLXDC1). These results were validated using brain xenografts of patient-derived glioma stem-like cells. Enforced expression of PLXDC1 in U87MG cells promoted brain infiltration along perivascular spaces. Importantly, PLXDC1 inhibition prevented perivascular infiltration and significantly increased the survival of bevacizumab-treated rats. Our study indicates that bevacizumab-induced brain infiltration is driven by vascular endothelium and depends on PLXDC1 activation of tumor cells

Deregulated expression of the imprinted DLK1-DIO3 region in Glioblastoma Stem-like Cells: tumor suppressor role of lncRNA MEG3

Background: Glioblastoma (GBM) stem-like cells (GSCs) are thought to be responsible for the maintenance and aggressiveness of GBM, the most common primary brain tumor in adults. This study aims at elucidating the involvement of deregulations within the imprinted DLK-DIO3 region on chromosome 14q32 in GBM pathogenesis. Methods: RT-PCR analyses were performed on GSCs and GBM tissues. Methylation analyses, gene expression and Reverse-Phase protein Array profiles were used to investigate the tumor suppressor function of MEG3. Results: Loss of expression of genes and non-coding RNAs within the DLK1-DIO3 region was observed in GSCs and GBM tissues compared to normal brain. This down-regulation is mainly mediated by epigenetic silencing. Kaplan-Meier analysis indicated that low expression of MEG3 and MEG8 lncRNAs significantly correlated with short survival in GBM patients. MEG3 restoration impairs tumorigenic abilities of GSCs in vitro by inhibiting cell growth, migration and colony formation and decreases in vivo tumor growth reducing infiltrative growth. These effects were associated with modulation of genes involved in cell adhesion and Epithelial to Mesenchymal Transition (EMT). Conclusions: In GBM, MEG3 acts as a tumor-suppressor mainly regulating cell adhesion, EMT and cell proliferation, thus providing a potential candidate for novel GBM therapies

IMMU-01. TEM-GBM: AN OPEN-LABEL, PHASE I/IIA DOSE-ESCALATION STUDY EVALUATING THE SAFETY AND EFFICACY OF GENETICALLY MODIFIED TIE-2 EXPRESSING MONOCYTES TO DELIVER IFN-A WITHIN GLIOBLASTOMA TUMOR MICROENVIRONMENT

Abstract Temferon is a macrophage-based treatment relying on ex-vivo transduction of autologous HSPCs to express immune-payloads within the TME. Temferon targets the immune-modulatory molecule IFN-a, to a subset of tumor infiltrating macrophages known as Tie-2 expressing macrophages (TEMs) due to the Tie2 promoter and a post-transcriptional regulation layer represented by miRNA-126 target sequences. As of 31st May 2021, 15-patients received Temferon (D+0) with follow-up of 3 – 693 days. After conditioning neutrophil and platelet engraftment occurred at D+13 and D+13.5, respectively. Temferon-derived differentiated cells, as determined be the number of vector copy per genome, were found within 14 days post treatment and persisted albeit at lower levels up to 18-months. Very low concentrations of IFN-a in the plasma (8.7 pg/ml-D+30) and in the CSF (1.6 pg/ml-D+30) were detected, suggesting tight regulation of transgene expression. Five-deaths occurred at D+322, +340, +402, +478 and +646 due to PD, and one at D+60 due to complications following the conditioning regimen. Eight-patients had progressive disease (range: D-11 to +239) as expected for this tumor type. SAEs include GGT elevation (possibly related to Temferon) and infections, venous thromboembolism, brain abscess, hemiparesis, seizures, anemia and general physical condition deterioration, compatible with ASCT, concomitant medications and PD. Four-patients underwent 2ndsurgery. Recurrent tumors had gene-marked cells and increased expression of ISGs compared to first surgery, indicative of local IFNa release by TEMs. In one patient, a stable lesion had a higher proportion of T cells and TEMs within the myeloid infiltrate and an increased ISGs than in the progressing lesion, detected in the same patient. Tumor-associated clones expanded in the periphery. TME characterization by scRNA and TCR-sequencing is ongoing. To date, Temferon is well tolerated, with no DLTs identified. The results provide initial evidence of Temferon potential to activate the immune system of GBM patients, as predicted by preclinical studies

Prognostic Impact of MGMT Promoter Methylation in Glioblastoma - A Systematic Review

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An unusual case of acute wandering paralysis

The authors reported on a 63-year-old diabetic male who developed a strange wandering hemiparesis affecting first left side and then right side, not consistent with a right parasagittal meningioma nor with ischemic stroke. The subsequent rapid worsening of clinical picture, with occurrence of paraparesis, urinary incontinence and midthoracic sensory level, together with the evidence of leucocytosis, led to the diagnosis of a T6-T7 spondylodiscitis with spinal cord compression. The authors underlied the difficulties in diagnosing this condition in the setting of general hospital practice and the importance of clinical and neurological examination

12-YEAR-OLD BOY WITH MULTIPLE BRAIN MASSES

The occurrence of more than one brain tumor in a single patient is not new, resulting from RT- or CT-induced neoplasms, syndromes or casual association. We report on the exceptional case of a 12-year-old boy harboring three different brain tumors with no definite correlation. The first MRI showed a medulloblastoma with signs of infratentorial and supratentorial tumor spreading, including a small frontal mass. Despite the good response to surgical and adjuvant treatment, the frontal mass remained unchanged and was excised, revealing a lipoastrocytoma. Finally, the possible local recurrence of the original medulloblastoma was a pilocytic astrocytoma with post-radiation alterations. Explanations of this very unusual association include radio-induced tumors, second tumors developing from remnants of medulloblastoma cancer stem cells, or the changing histology after adjuvant therapy

Radiation-induced malignant transformation of craniopharyngiomas: Reply

No abstract availabl

Letter: Allograft Nerve Repair Reduces Postoperative Neuropathic Pain Following Nerve Biopsy

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