Project description:Recurrent fusion genes involving C11orf95, C11orf95-RELA, have been identified only in supratentorial ependymomas among primary CNS tumors. Here, we report hitherto histopathologically unclassifiable high-grade tumors, under the tentative label of "ependymoma-like tumors with mesenchymal differentiation (ELTMDs)," harboring C11orf95-NCOA1/2 or -RELA fusion. We examined the clinicopathological and molecular features in five cases of ELTMDs. Except for one adult case (50 years old), all cases were in children ranging from 1 to 2.5 years old. All patients presented with a mass lesion in the cerebral hemisphere. Histologically, all cases demonstrated a similar histology with a mixture of components. The major components were embryonal-appearing components forming well-delineated tumor cell nests composed of small uniform cells with high proliferative activity, and spindle-cell mesenchymal components with a low- to high-grade sarcoma-like appearance. The embryonal-appearing components exhibited minimal ependymal differentiation including a characteristic EMA positivity and tubular structures, but histologically did not fit with ependymoma because they lacked perivascular pseudorosettes, a histological hallmark of ependymoma, formed well-delineated nests, and had diffuse and strong staining for CAM5.2. Molecular analysis identified C11orf95-NCOA1, -NCOA2, and -RELA in two, one, and two cases, respectively. t-distributed stochastic neighbor embedding analysis of DNA methylation data from two cases with C11orf95-NCOA1 or -NCOA2 and a reference set of 380 CNS tumors revealed that these two cases were clustered together and were distinct from all subgroups of ependymomas. In conclusion, although ELTMDs exhibited morphological and genetic associations with supratentorial ependymoma with C11orf95-RELA, they cannot be regarded as ependymoma. Further analyses of more cases are needed to clarify their differences and similarities.
Project description:Abstract Glioblastoma (GBM) is the most common and aggressive primary brain cancer. Current standard-of-care includes surgery followed by concurrent therapy with radiation and temozolomide (TMZ) and maintenance TMZ. Almost all GBM patients experience recurrent/progressive disease, and median survival after recurrence is 3–9 months. Effective therapies for recurrent GBM (rGBM) are lacking, representing a significant unmet medical need. Unmethylated promoter for O6-methylguanine-DNA-methyltransferase (MGMT) is a validated biomarker for TMZ-resistance and is correlated with a poor prognosis. Second-line treatment with the anti-angiogenic agent bevacizumab (BEV) has not improved survival, and 5-year survival is less than 3%. VAL-083 is a bi-functional DNA-targeting agent rapidly inducing interstrand cross-links at N7-guanine, leading to DNA double-strand breaks and cell-death. VAL-083s cytotoxicity is independent of MGMT status, and VAL-083 overcomes TMZ-resistance in GBM cell lines, GBM cancer stem cells, and in vivo GBM models. We completed a 3 + 3 dose-escalation trial of VAL-083 in TMZ- and BEV-refractory rGBM. 40mg/m2/day given on days 1,2,3 of a 21-day cycle was generally well-tolerated, and this dose was selected for further clinical evaluation in Phase 2 trials. The trial described here is an ongoing single-arm, biomarker-driven Phase 2 trial in MGMT-unmethylated BEV-naïve adult rGBM. In this trial, 48 patients will receive VAL-083 40mg/m2/day on days 1,2,3 of a 21-day cycle. Tumor response will be assessed by MRI approximately every 42 days, per RANO criteria. The primary objective of this study is to determine if VAL-083 improves median overall survival (mOS) for MGMT-unmethylated rGBM patients compared to a historical mOS of 7.1 months for such patients treated with lomustine (EORTC26101). Secondary efficacy endpoints include progression-free survival (PFS), overall response rate (ORR), duration of response (DOR), and quality-of-life (QOL) evaluation using the MD Anderson Symptom Inventory-Brain Tumor Module (MDASI-BT) self-reporting tool. Enrollment and safety data update will be provided at the meeting. Clinicaltrials.gov identifier: NCT02717962.
Project description:Recurrent C11orf95-RELA fusions (RELAFUS) are the hallmark of supratentorial ependymomas. The presence of RELA as the fusion partner indicates a close association of aberrant NF-κB activity with tumorigenesis. However, the oncogenic role of the C11orf95 has not been determined. Here, we performed ChIP-seq analyses to explore genomic regions bound by RELAFUS and H3K27ac proteins in human 293T and mouse ependymoma cells. We then utilized published RNA-Seq data from human and mouse RELAFUS tumors and identified target genes that were directly regulated by RELAFUS in these tumors. Subsequent transcription factor motif analyses of RELAFUS target genes detected a unique GC-rich motif recognized by the C11orf95 moiety, that is present in approximately half of RELAFUS target genes. Luciferase assays confirmed that a promoter carrying this motif is sufficient to drive RELAFUS-dependent gene expression. Further, the RELAFUS target genes were found to be overlapped with Rela target genes primarily via non-canonical NF-κB binding sites. Using a series of truncation and substitution mutants of RELAFUS, we also show that the activation domain in the RELAFUS moiety is necessary for the regulation of gene expression of these RELAFUS target genes. Lastly, we performed an anti-cancer drug screening with mouse ependymoma cells and identified potential anti-ependymoma drugs that are related to the oncogenic mechanism of RELAFUS. These findings suggested that RELAFUS might induce ependymoma formation through oncogenic pathways orchestrated by both C11orf95 and RELA target genes. Thus, our study unveils a complex gene function of RELAFUS as an oncogenic transcription factor in RELAFUS positive ependymomas.
Project description:BACKGROUND:A desperate need for novel therapies in pediatric ependymoma (EPN) exists, as chemotherapy remains ineffective and radiotherapy often fails. EPN have significant infiltration of immune cells, which correlates with outcome. Immune checkpoint inhibitors provide an avenue for new treatments. This study characterizes tumor-infiltrating immune cells in EPN and aims at predicting candidates for clinical trials using checkpoint inhibitors targeting PD-L1/PD-1 (programmed death ligand 1/programmed death 1). METHODS:The transcriptomic profiles of the primary study cohort of EPN and other pediatric brain tumors were interrogated to identify PD-L1 expression levels. Transcriptomic findings were validated using the western blotting, immunohistochemistry and flow cytometry. RESULTS:We evaluated PD-L1 mRNA expression across four intracranial subtypes of EPN in two independent cohorts and found supratentorial RELA fusion (ST-RELA) tumors to have significantly higher levels. There was a correlation between high gene expression and protein PD-L1 levels in ST-RELA tumors by both the western blot and immunohistochemisty. The investigation of EPN cell populations revealed PD-L1 was expressed on both tumor and myeloid cells in ST-RELA. Other subtypes had little PD-L1 in either tumor or myeloid cell compartments. Lastly, we measured PD-1 levels on tumor-infiltrating T cells and found ST-RELA tumors express PD-1 in both CD4 and CD8 T cells. A functional T-cell exhaustion assay found ST-RELA T cells to be exhausted and unable to secrete IFNγ on stimulation. CONCLUSIONS:These findings in ST-RELA suggest tumor evasion and immunsuppression due to PD-L1/PD-1-mediated T-cell exhaustion. Trials of checkpoint inhibitors in EPN should be enriched for ST-RELA tumors.
Project description:Abstract Glioblastoma (GBM) is the most common CNS tumor. Patients with recurrent GBM have few treatment options and dismal prognosis. O6-methylguanine-DNA-methyltransferase (MGMT) is correlated with resistance to standard of care treatment with temozolomide and poor patient outcomes. Dianhydrogalactitol (VAL-083) is a bi-functional alkylating agent with a distinct mechanism-of-action differentiating it from other alkylating agents used in the treatment of GBM and other CNS tumors. VAL-083 readily crosses the blood-brain barrier and accumulates in brain tumor tissue. VAL-083 has demonstrated MGMT-independent cytotoxicity in multiple GBM cell-lines and cancer stem cells and is able to overcome TMZ-resistance in vitro demonstrating a different mechanism of action. In multiple prior NCI-sponsored clinical trials VAL-083 showed promise against CNS tumors. We recently concluded a phase I/II clinical trial studying VAL-083 in recurrent GBM patients failing temozolomide and bevacizumab, and data suggests a potential for VAL-083 to offer clinically meaningful survival benefits in patients who have failed or are unlikely to respond to currently available chemotherapeutic regimens. In the phase I portion of the trial, VAL-083, 40 mg/m2/day x 3 every 21 days was well-tolerated and this dose was selected for study in the phase II expansion phase. We are initiating multiple clinical trials targeting adult patients with chemoresistant GBM due to MGMT expression. Enrollment is anticipated to be initiated in early 2017. These trials include i) a pivotal, randomized Phase 3 study measuring survival outcome compared to “physician’s choice” control, which, if successful, would serve as the basis for a New Drug Application (NDA) submission for VAL-083. The control arm will consist of a limited number of salvage chemotherapies currently utilized in bevacizumab-failed GBM. ii) A single-arm, biomarker-driven, Phase 2 study to determine if treatment of MGMT-unmethylated recurrent GBM with VAL-083 improves overall survival at 9 months, compared to historical control in bevacizumab-naïve patients (clinicaltrials.gov identifier: NCT02717962). iii) A single arm Phase 2 study to confirm the tolerability of DelMar’s dosing regimen in combination with radiotherapy and to explore the activity of VAL-083 in newly diagnosed MGMT-unmethylated GBM patients whose tumors are known to express high MGMT levels. The results of these studies may support a new treatment paradigm in chemotherapeutic regimens for the treatment of GBM. Enrollment updates and study design details will be presented at the meeting.
Project description:Supratentorial ependymoma (ST-EPN) is a type of malignant brain tumor mainly seen in children. Since 2014, it has been known that an intrachromosomal fusion C11orf95-RELA is an oncogenic driver in ST-EPN [Parker et al. Nature 506:451-455 (2014); Pietsch et al. Acta Neuropathol 127:609-611 (2014)] but the molecular mechanisms of oncogenesis are unclear. Here we show that the C11orf95 component of the fusion protein dictates DNA binding activity while the RELA component is required for driving the expression of ependymoma-associated genes. Epigenomic characterizations using ChIP-seq and HiChIP approaches reveal that C11orf95-RELA modulates chromatin states and mediates chromatin interactions, leading to transcriptional reprogramming in ependymoma cells. Our findings provide important characterization of the molecular underpinning of C11orf95-RELA fusion and shed light on potential therapeutic targets for C11orf95-RELA subtype ependymoma.
Project description:Abstract Glioblastoma (GBM) is the most common and aggressive primary brain cancer. Current standard-of-care includes surgery, radiation and treatment with temozolomide (TMZ), however nearly all tumors recur and the prognosis for recurrent GBM is dismal. Resistance to TMZ is correlated with expression of the DNA repair enzyme O6-methylguanine-DNA-methyltransferase (MGMT), which is highly expressed in a majority of GBM tumors. Dianhydrogalactitol (VAL-083) is a first-in-class bi-functional DNA-targeting agent that exhibited activity against GBM in NCI-sponsored clinical trials both as a single agent and in combination with radiotherapy. VAL-083 readily crosses the blood-brain barrier and accumulates in brain tumor tissue. We have demonstrated that VAL-083 targets N7-Guanine and rapidly induces interstrand DNA cross-links, leading to DNA double-strand breaks, S/G2 cell-cycle arrest and cell death in GBM cell lines and GBM cancer stem cells (CSCs) in vitro. This unique N7-guanine targeting mechanism not only circumvents MGMT-mediated chemo-resistance but also maintains cytotoxic activity in cancer cells deficient in mismatch repair (MMR). These data suggest VAL-083 may offer a superior chemotherapeutic alternative in the treatment of MGMT-unmethylated or MMR deficient GBM. Here, we provide an update of ongoing clinical trials with VAL-083 in MGMT-unmethylated GBM: i) a single-arm, biomarker-driven, Phase II study to determine if VAL-083 treatment of MGMT-unmethylated adult GBM patients at first recurrence/progression, prior to bevacizumab improves survival compared to historical lomustine control (clinicaltrials.gov identifier: NCT02717962); ii) a single-arm, biomarker-driven, Phase II study to confirm the tolerability and efficacy of VAL-083 in combination with radiotherapy in newly diagnosed MGMT-unmethylated GBM patients (clinicaltrials.gov identifier: NCT03050736). The results of these studies may support a new treatment paradigm in for the treatment of MGMT-unmethylated GBM.
Project description:BackgroundSupratentorial RELA fusion (ST-RELA) ependymomas (EPNs) are resistant tumors without an approved chemotherapeutic treatment. Unfortunately, the molecular mechanisms that lead to chemoresistance traits of ST-RELA remain elusive. The aim of this study was to assess RELA fusion-dependent signaling modules, specifically the role of the Hedgehog (Hh) pathway as a novel targetable vulnerability in ST-RELA.MethodsGene expression was analyzed in EPN from patient cohorts, by microarray, RNA-seq, qRT-PCR, and scRNA-seq. Inhibitors against Smoothened (SMO) (Sonidegib) and Aurora kinase A (AURKA) (Alisertib) were evaluated. Protein expression, primary cilia formation, and drug effects were assessed by immunoblot, immunofluorescence, and immunohistochemistry.ResultsHh components were selectively overexpressed in EPNs induced by the RELA fusion. Single-cell analysis showed that the Hh signature was primarily confined to undifferentiated, stem-like cell subpopulations. Sonidegib exhibited potent growth-inhibitory effects on ST-RELA cells, suggesting a key role in active Hh signaling; importantly, the effect of Sonidegib was reversed by primary cilia loss. We, thus, tested the effect of AURKA inhibition by Alisertib, to induce cilia stabilization/reassembly. Strikingly, Alisertib rescued ciliogenesis and synergized with Sonidegib in killing ST-RELA cells. Using a xenograft model, we show that cilia loss is a mechanism for acquiring resistance to the inhibitory effect of Sonidegib. However, Alisertib fails to rescue cilia and highlights the need for other strategies to promote cilia reassembly, for treating ST-RELA tumors.ConclusionOur study reveals a crucial role for the Hh pathway in ST-RELA tumor growth, and suggests that rescue of primary cilia represents a vulnerability of the ST-RELA EPNs.
Project description:Abstract Current standard-of-care for glioblastoma (GBM) includes surgery followed by concurrent therapy with radiation and temozolomide (TMZ) followed by adjuvant TMZ (days 1–5 every 28 days. Almost all GBM patients experience recurrent/progressive disease, with a median survival after recurrence of 3–9 months. Second-line treatment for recurrent GBM with bevacizumab (BEV) has not improved survival, and effective therapies for GBM are lacking. Unmethylated promoter for O6-methylguanine-DNA-methyltransferase (MGMT) is a validated biomarker for TMZ-resistance and is correlated with poor patient prognosis. VAL-083 is a bi-functional DNA-targeting agent which rapidly induces interstrand DNA cross-links at N7-guanine, induces double-strand breaks and acts independent of MGMT DNA repair. The current ongoing trial is a biomarker-driven Phase 2 study in MGMT-unmethylated BEV-naïve adult GBM. The primary objective of this study is to determine the effect of VAL-083 on median overall survival (mOS) for MGMT-unmethylated GBM patients compared to historical control. Secondary efficacy endpoints include progression-free survival (PFS), overall response rate (ORR), duration of response (DOR), and quality-of-life. Thirty-five (35) subjects with recurrent GBM have received 40 mg/m2/day VAL-083 on days 1, 2, 3 of a 21-day cycle as the starting dose. Myelosuppression is the most common adverse event and a higher potential for this toxicity correlated with those patients who received a higher number of cycles of prior TMZ maintenance therapy, (>5 cycles vs. ≤5 cycles, p< 0.05). To minimize the potential for hematological toxicity in rGBM, subsequent subjects initiated treatment at 30 mg/m2/d VAL-083 x 3 consecutive days every 21 days. In addition, since TMZ is of limited value in the MGMT-unmethylated setting, a second arm in newly diagnosed GBM has been included to explore whether substituting TMZ with VAL-083 offers clinical benefit and extends the time to recurrence. Enrollment, safety data and study updates will be presented at the meeting. Clinicaltrials.gov identifier: NCT02717962.