scholarly journals MODL-31. RADIATION-DERIVED TREATMENT-RESISTANT PDX AND CELL CULTURE MODELS RECAPITULATE THE CHARACTERISTICS OF MATCHED PRIMARY/RECURRENT PEDIATRIC HIGH-GRADE GLIOMA

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii417-iii417
Author(s):  
Aaron J Knox ◽  
Patrick Flannery ◽  
Anjali Zukosky ◽  
John DeSisto ◽  
Bridget Sanford ◽  
...  

Abstract BACKGROUND Pediatric high-grade glioma (pHGG) is the most common cause of childhood cancer death. Recurrence after therapy is a major challenge, since recurrent pHGG proliferates aggressively and resists therapy. We developed and validated preclinical models of matched primary and recurrent tumors, providing a method to study recurrence and potential therapies. METHODS We irradiated H3K27M thalamic pHGG cells (BT245) (8 Gy/week,2Gy fractions x3 weeks) and propagated the surviving cells (BT245R). We developed a murine recurrence model by orthotopically implanting BT245 cells, irradiating the resultant tumors (4 Gy/day x2d) and propagating irradiated (BT245RM) or control (BT245CM) tumor cells at endpoint. We performed phenotypic analyses, RNA-Seq, and drug testing. RESULTS BT245R cells were more stemlike than BT245, with an 8-fold greater rate of neurosphere formation (p<0.03). Geneset enrichment analysis showed similar molecular changes in BT245RM cells and primary/recurrent H3K27M pHGG patient sample pair, including relaxation of the G2/M cell cycle checkpoint (Hallmark_G2M_Checkpoint: BT245RM NES=-5.95, FDR=0.0; patient NES=-5.86, FDR=0.0), downregulation of MYC targets (Hallmark_MYC_Targets_V1: BT245RM NES=-7.43, FDR=0.0; patient NES=-5.86, FDR=0.0), and decreased differentiation (Go_Regulation_of_Stem_Cell_Differentiation: BT245RM NES=-3.35, FDR=0.0; patient NES=-3.15, FDR=0.0). Enrichment of the protein_kinase_C_signaling in BT245RM (NES=2.18,FDR=0.03) suggested response to MAPK pathway inhibition. BT245R cells were twice as sensitive as BT245 cells to the MEK inhibitor trametinib (p<0.05). CONCLUSIONS Our neurosphere and murine orthotopic patient-derived xenograft models recapitulate gene expression changes of matched primary/recurrent pHGG. RNA-Seq analysis validated the model against patient samples and identified trametinib as potentially effective in recurrent pHGG.

2019 ◽  
Vol 21 (Supplement_2) ◽  
pp. ii87-ii87
Author(s):  
Kallen Schwark ◽  
Amy Bruzek ◽  
Chandan Kumar-Sinha ◽  
Sylvia Escolero ◽  
Bernard Marini ◽  
...  

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii350-iii350
Author(s):  
Quentin Fuchs ◽  
Marina Pierrevelcin ◽  
Christophe Papin ◽  
Monique Dontenwill ◽  
Natacha Entz-Werlé

Abstract Pediatric high-grade gliomas (pHGGs) have a very dismal prognosis and need new innovative strategy for treatment. Despite the past discovery of histone H3 driver mutations, we are not able for instance to stop this induced epigenetic remodulation. Therefore, proactive translational studies wish to go further discovering new targetable proteins in pHGG. In our past clinical work, we were able to link significantly HIF-2alpha to a worse pHGG outcome and to their treatment resistance. We designed this new work to determine in several patient-derived cell lines (6 PDCLs) with or without H3.3 mutation the variation of HIF-2alpha, its role, its induction in normoxic and hypoxic microenvironment and its transcriptional targets using RNAseq, metabolomics and ChipSeq analyses. Complementary functional analyses were performed using siRNA strategy during cultures and migration assays. Finally, preclinical drug testing involving commercialized and non-commercialized HIF-2alpha specific inhibitors in the same PDCLs were evaluating their antiproliferative and pro-apoptotic effect. Our results confirmed the central role of HIF-2alpha in cell resistance to treatment, in pHGG stemness features and its direct link with metabolism adaptation and histone interaction. After the confirmation of its frequent presence in multiple PDCLs initiated from thalamic pHGGs and DIPG, we were using inhibitors in a single and combinatorial strategy targeting HIF-2alpha plus another hypoxia biomarker (mTor). This preclinical targeting was highly effective to favor cell arrest, apoptosis and to stop cell migration. In conclusion, HIF-2alpha seem to be a major biomarker in pHGGs that might be targeted giving a useful new opportunity for pHGG treatments.


2015 ◽  
Vol 17 (suppl 3) ◽  
pp. iii12-iii12
Author(s):  
C. Lasthaus ◽  
M. Litzler ◽  
C. Bour ◽  
D. Guenot ◽  
N. Entz-Werle

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii351-iii351
Author(s):  
Frank Dubois ◽  
Ofer Shapira ◽  
Noah Greenwald ◽  
Travis Zack ◽  
Jessica W Tsai ◽  
...  

Abstract BACKGROUND Driver single nucleotide variants (SNV) and somatic copy number aberrations (SCNA) of pediatric high-grade glioma (pHGGs), including Diffuse Midline Gliomas (DMGs) are characterized. However, structural variants (SVs) in pHGGs and the mechanisms through which they contribute to glioma formation have not been systematically analyzed genome-wide. METHODS Using SvABA for SVs as well as the latest pipelines for SCNAs and SNVs we analyzed whole-genome sequencing from 174 patients. This includes 60 previously unpublished samples, 43 of which are DMGs. Signature analysis allowed us to define pHGG groups with shared SV characteristics. Significantly recurring SV breakpoints and juxtapositions were identified with algorithms we recently developed and the findings were correlated with RNAseq and H3K27ac ChIPseq. RESULTS The SV characteristics in pHGG showed three groups defined by either complex, intermediate or simple signature activities. These associated with distinct combinations of known driver oncogenes. Our statistical analysis revealed recurring SVs in the topologically associating domains of MYCN, MYC, EGFR, PDGFRA & MET. These correlated with increased mRNA expression and amplification of H3K27ac peaks. Complex recurring amplifications showed characteristics of extrachromosomal amplicons and were enriched in coding SVs splitting protein regulatory from effector domains. Integrative analysis of all SCNAs, SNVs & SVs revealed patterns of characteristic combinations between potential drivers and signatures. This included two distinct groups of H3K27M DMGs with either complex or simple signatures and different combinations of associated variants. CONCLUSION Recurrent SVs associate with signatures shaped by an underlying process, which can lead to distinct mechanisms to activate the same oncogene.


2020 ◽  
Vol 108 (3) ◽  
pp. e239-e240
Author(s):  
L.J. Sudmeier ◽  
T. Morgan ◽  
P. Mendoza ◽  
J. Switchenko ◽  
E. Schreibmann ◽  
...  

2016 ◽  
Vol 18 (suppl 3) ◽  
pp. iii55.2-iii55
Author(s):  
John T. Lucas ◽  
Nick Serrano ◽  
Hyun Kim ◽  
Yimei Li ◽  
Alberto Broniscer ◽  
...  

2019 ◽  
Vol 1 (Supplement_2) ◽  
pp. ii44-ii44
Author(s):  
Yoshihiro Tsukamoto ◽  
Manabu Natsumeda ◽  
Masayasu Okada ◽  
Takeyoshi Eda ◽  
Junichi Yoshimura ◽  
...  

Abstract INTRODUCTION Bevacizumab (BEV) therapy has been used for pediatric high grade glioma,however the evidence and effectiveness are not understood yet. METHODS We report 7 cases (age 2 to 10 years old) of pediatric high grade glioma treated with BEV. One case is thalamic diffuse midline glioma H3K27 mutant (DMGH3K27M),one case is brain stem DMGH3K27M,one case is cerebellar high grade glioma,and 4 cases are diffuse intrinsic pontine glioma (DIPG) diagnosed clinically without biopsy. 5 cases were treated with BEV when diagnosed as recurrence after chemo-radiotherapy. One case was treated for rapid tumor progression during radiotherapy. One case was started on BEV therapy with radiation and concomitant temozolomide therapy. RESULT The number of times of BEV was 2 to 13 times (median 7 times). The period of BEV was 1 to 9 months (median 4 months). One case which was treated with BEV at rapid progression during radiation showed good response on imaging and improvement of symptoms. 4 of 5 cases who were treated at recurrence clinically showed mild symptomatic improvement. One case treated with BEV and radiotherapy initially was not evaluated. The adverse effects of BEV included wound complication of tracheostomy and rash. CONCLUSION BEV showed good response for rapid progression during radiotherapy,and mild response for recurrence cases. BEV is thought to be an effective therapeutic agent for pediatric HGG at recurrence and rapid tumor progression during radiotherapy.


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