Comparative Analysis of DNA Repair in Stem and Nonstem Glioma Cell Cultures

Ropolo, Monica; Daga, Antonio; Griffero, Fabrizio; Foresta, Mara; Casartelli, Gianluigi; Zunino, Annalisa; Poggi, Alessandro; Cappelli, Enrico; Zona, Gianluigi; Spaziante, Renato; Corte, Giorgio; Fròsina, Guido

doi:10.1158/1541-7786.mcr-08-0409

Cited by 172 publications

(165 citation statements)

References 34 publications

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“…25 In these conditions, cells adopted a round morphology and formed spheres after several days (data not shown), in parallel to increased MerTK expression (Figure 4a). Interestingly, other GBM cell lines growing under stem cell culture conditions either died (data not shown) or showed adherent features with an elongated morphology (Supplementary Figure 4a).…”

Section: Mertk Is Overexpressed In Malignant Gliomasmentioning

confidence: 81%

Mer receptor tyrosine kinase promotes invasion and survival in glioblastoma multiforme

et al. 2012

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The infiltration of glioma cells into adjacent tissue is one of the major obstacles in the therapeutic management of malignant brain tumours, in most cases precluding complete surgical resection. Consequently, malignant glioma patients almost invariably experience tumour recurrences. Within the brain, glioma cells migrate rapidly either amoeboidly or mesenchymally to invade surrounding structures, in dependence on the extracellular environment. In addition, radiotherapy, frequently applied as adjuvant therapeutic modality, may enhance tumour cell mobility. Here, we show that the receptor tyrosine kinase Mer (MerTK) is overexpressed in glioblastoma multiforme (GBM) and that this is accompanied with increased invasive potential. MerTK expression is maintained in primary GBM-derived tumour spheres under stem cell culture conditions but diminishes significantly in serum-containing cultures with concomitant downregulation of Nestin and Sox2. Depletion of MerTK disrupts the rounded morphology of glioma cells and decreases their invasive capacity. Furthermore, the expression and phosphorylation of myosin light chain 2 are strongly associated with MerTK activity, indicating that the effect of MerTK on glioma cell invasion is mediated by actomyosin contractility. Finally, DNA damage robustly triggers the upregulation and phosphorylation of MerTK, which protects cells from apoptosis. This effect is strongly impaired upon MerTK depletion or overexpression of an inactive MerTK mutant. Collectively, our data suggests that MerTK is a novel therapeutic target in the treatment of the malignant gliomas.

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Section: Mertk Is Overexpressed In Malignant Gliomasmentioning

confidence: 81%

Mer receptor tyrosine kinase promotes invasion and survival in glioblastoma multiforme

et al. 2012

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“…However, analysis of proliferation over an 80-day period showed radiosensitization after either one, two or three KU60019 plus IR treatments (Figs. 5e [4][5][6] and f 4,5 ; Table 1). Previous studies have identified subgroups of GB based on genetic and epigenetic variations of a number of genes including H3F3A and IDH1.…”

Section: Efficacy On Adult and Pediatric Tumorsmentioning

confidence: 99%

“…2 GIC lines deriving from adult GB have been previously described. 2,6 The pediatric GIC lines 239/12 and 170/OG have been obtained from surgical resection of an anaplastic astrocytoma (WHO grade III) in a 14-year-old male and a GB (WHO grade IV) in a 12-year-old male, respectively. Both patients died because of the tumors within 3 years from the diagnosis.…”

Section: Cell Lines and Culture Conditionsmentioning

confidence: 99%

“…Development and characterization of orthotopic tumors were obtained as described. 2,6 Radiotherapy of orthotopic GB was performed on the head of mice, under anesthesia, with a HDR (high dose rate) brachytherapy delivery system (microSelectron Digital, Nucletron Elekta, Stockholm, Sweden) by a Leipzig applicator of 10-mm diameter for a source of 192 Ir. The dose distribution was calculated on mice magnetic resonance imaging (MRI) and the verification of in vivo delivered dose was performed with two radiochromic films (Gafchromic V R EBT2, Ashland, Covington, KY) placed, respectively, between the applicator and the mice head and under the mice snout.…”

Section: Ced Development and Characterization Of Orthotopic Tumors Amentioning

confidence: 99%

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Pharmacokinetics, pharmacodynamics and efficacy on pediatric tumors of the glioma radiosensitizer KU60019

Vecchio

Daga

Carra

et al. 2014

Intl Journal of Cancer

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We have recently reported that glioblastoma (GB)-initiating cells (GIC) with low expression and/or mutation of TP53 and high expression of PI3K ("responder" genetic profile) can be effectively and safely radiosensitized by the ATM inhibitor KU60019. We report here on drug's diffusion and elimination from the animal body and brain, its effects on orthotopic GB and efficacy toward pediatric GIC. Healthy mice were infused by convection enhanced delivery (CED) with KU60019 and the drug kinetics followed by high performance liquid chromatography-mass spectrometry. Already at the end of CED, KU60019 had diffused from the injection site to the ipsilateral and, to a lower extent, controlateral hemisphere. After 24 hr, no drug could be detected all over the brain or in other organs, indicating rapid draining and excretion. After intraperitoneal injection, traces only of KU60019 could be detected in the brain, indicating inability to cross the brain-blood barrier. Consistent with the induction of cell cycle progression previously observed in vitro, KU60019 stimulated proliferation of orthotopic GB cells with the highest effect observed 96 hr after drug delivery. Adult GIC with high expression of TP53 and low expression of PI3K could be radiosensitized by KU60019, although less promptly than GIC bearing the "responder" profile. Consistent with the kinetics of proliferation induction, the highest radiosensitizing effect was observed 96 hr after delivery of KU60019 to GIC. Pediatric GIC could be similarly radiosensitized after exposure to KU60019. The results indicate that ATM inhibition may allow to radiosensitize a wide range of adult and pediatric high-grade gliomas.

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“…Investigations characterizing subpopulations of aberrant stem cells have shown efficient DSB repair through various DNA damage markers, but no specific pathways have been identified to explain the increased survival (7). Recent reports also provided evidence for differences in radiosensitivity between subpopulations of glioma-initiating cells (8)(9)(10), suggesting disparity in DNA repair efficiency. Whether DNA repair is a major mechanism of radioresistance in glioma-initiating cells remains controversial.…”

Section: Introductionmentioning

confidence: 99%

A Role for Homologous Recombination and Abnormal Cell-Cycle Progression in Radioresistance of Glioma-Initiating Cells

Lim

Roberts

Day

et al. 2012

Molecular Cancer Therapeutics

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Glioblastoma multiforme (GBM) is the most common form of brain tumor with a poor prognosis and resistance to radiotherapy. Recent evidence suggests that glioma-initiating cells play a central role in radioresistance through DNA damage checkpoint activation and enhanced DNA repair. To investigate this in more detail, we compared the DNA damage response in nontumor forming neural progenitor cells (NPC) and glioma-initiating cells isolated from GBM patient specimens. As observed for GBM tumors, initial characterization showed that gliomainitiating cells have long-term self-renewal capacity. They express markers identical to NPCs and have the ability to form tumors in an animal model. In addition, these cells are radioresistant to varying degrees, which could not be explained by enhanced nonhomologous end joining (NHEJ). Indeed, NHEJ in glioma-initiating cells was equivalent, or in some cases reduced, as compared with NPCs. However, there was evidence for more efficient homologous recombination repair in glioma-initiating cells. We did not observe a prolonged cell cycle nor enhanced basal activation of checkpoint proteins as reported previously. Rather, cell-cycle defects in the G 1 -S and S-phase checkpoints were observed by determining entry into S-phase and radioresistant DNA synthesis following irradiation. These data suggest that homologous recombination and cell-cycle checkpoint abnormalities may contribute to the radioresistance of glioma-initiating cells and that both processes may be suitable targets for therapy.

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Comparative Analysis of DNA Repair in Stem and Nonstem Glioma Cell Cultures

Cited by 172 publications

References 34 publications

Mer receptor tyrosine kinase promotes invasion and survival in glioblastoma multiforme

Mer receptor tyrosine kinase promotes invasion and survival in glioblastoma multiforme

Pharmacokinetics, pharmacodynamics and efficacy on pediatric tumors of the glioma radiosensitizer KU60019

A Role for Homologous Recombination and Abnormal Cell-Cycle Progression in Radioresistance of Glioma-Initiating Cells

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