MEK Inhibition Suppresses Growth of Atypical Teratoid/Rhabdoid Tumors.
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ABSTRACT:
SUBMITTER: Shahab S
PROVIDER: S-EPMC7821707 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundAtypical teratoid/rhabdoid tumors (AT/RT) are rare, but highly aggressive. These entities are of embryonal origin occurring in the central nervous system (CNS) of young children. Molecularly these tumors are driven by a single hallmark mutation, resulting in inactivation of SMARCB1 or SMARCA4. Additionally, activation of the MAPK signaling axis and preclinical antitumor efficacy of its inhibition have been described in AT/RT.MethodsWe established and validated a patient-derived neurosphere culture and xenograft model of sonic hedgehog (SHH) subtype AT/RT, at diagnosis and relapse from the same patient. We set out to study the vascular phenotype of these tumors to evaluate the integrity of the blood-brain barrier (BBB) in AT/RT. We also used the model to study combined mitogen-activated protein kinase kinase (MEK) and maternal embryonic leucine zipper kinase (MELK) inhibition as a therapeutic strategy for AT/RT.ResultsWe found MELK to be highly overexpressed in both patient samples of AT/RT and our primary cultures and xenografts. We identified a potent antitumor efficacy of the MELK inhibitor OTSSP167, as well as strong synergy with the MEK inhibitor trametinib, against primary AT/RT neurospheres. Additionally, vascular phenotyping of AT/RT patient material and xenografts revealed significant BBB aberrancies in these tumors. Finally, we show in vivo efficacy of the non-BBB penetrable drugs OTSSP167 and trametinib in AT/RT xenografts, demonstrating the therapeutic implications of the observed BBB deficiencies and validating MEK/MELK inhibition as a potential treatment.ConclusionAltogether, we developed a combination treatment strategy for AT/RT based on MEK/MELK inhibition and identify therapeutically exploitable BBB deficiencies in these tumors.
| S-EPMC6954444 | biostudies-literature
Project description:BackgroundAtypical teratoid/thabdoid tumor (AT/RT) remains a difficult-to-treat tumor with a 5-year overall survival rate of 15%-45%. Proteasome inhibition has recently been opened as an avenue for cancer treatment with the FDA approval of bortezomib (BTZ) in 2003 and carfilzomib (CFZ) in 2012. The aim of this study was to identify and characterize a pre-approved targeted therapy with potential for clinical trials in AT/RT.MethodsWe performed a drug screen using a panel of 134 FDA-approved drugs in 3 AT/RT cell lines. Follow-on in vitro studies used 6 cell lines and patient-derived short-term cultures to characterize selected drug interactions with AT/RT. In vivo efficacy was evaluated using patient derived xenografts in an intracranial murine model.ResultsBTZ and CFZ are highly effective in vitro, producing some of the strongest growth-inhibition responses of the evaluated 134-drug panel. Marizomib (MRZ), a proteasome inhibitor known to pass the blood-brain barrier (BBB), also strongly inhibits AT/RT proteasomes and generates rapid cell death at clinically achievable doses in established cell lines and freshly patient-derived tumor lines. MRZ also significantly extends survival in an intracranial mouse model of AT/RT.ConclusionsMRZ is a newer proteasome inhibitor that has been shown to cross the BBB and is already in phase II clinical trials for adult high-grade glioma (NCT NCT02330562 and NCT02903069). MRZ strongly inhibits AT/RT cell growth both in vitro and in vivo via a moderately well-characterized mechanism and has direct translational potential for patients with AT/RT.
| S-EPMC7236404 | biostudies-literature
Project description:Atypical teratoid rhabdoid tumor (ATRT) is an aggressive pediatric brain tumor with limited therapeutic options. The hypothesis for this study was that the Wnt pathway triggered by the Wnt5B ligand plays an important role in ATRT biology. To address this hypothesis, the role of WNT5B and other Wnt pathway genes was analyzed in ATRT tissues and ATRT primary cell lines.Transcriptome-sequencing analyses were performed using nanoString platforms, immunohistochemistry, Western blotting, quantitative reverse transcriptase PCR, immunoprecipitation, short interference RNA studies, cell viability studies, and drug dose response (DDR) assays.Our transcriptome-sequencing results of Wnt pathway genes from ATRT tissues and cell lines indicated that the WNT5B gene is significantly upregulated in ATRT samples compared with nontumor brain samples. These results also indicated a differential expression of both canonical and noncanonical Wnt genes. Imunoprecipitation studies indicated that Wnt5B binds to Frizzled1 and Ryk receptors. Inhibition of WNT5B by short interference RNA decreased the expression of FRIZZLED1 and RYK. Cell viability studies a indicated significant decrease in cell viability by inhibiting Frizzled1 receptor. DDR assays showed promising results with some inhibitors.These promising therapeutic options will be studied further before starting a translational clinical trial. The success of these options will improve care for these patients.
| S-EPMC4483069 | biostudies-literature
Project description:Atypical teratoid/rhabdoid tumors (AT/RTs) are lethal central nervous system tumors, which are primarily diagnosed in infants. Current treatments for AT/RTs include surgery, radiotherapy, and chemotherapy; these treatments have poor prognoses and challenging side effects. The pivotal genetic event in AT/RT pathogenesis comprises the inactivation of SMARCB1 or SMARCA4. Recent epigenetic studies have demonstrated mutual and subtype-specific epigenetic derangements that drive tumorigenesis; the exploitation of these potential targets might improve the dismal treatment outcomes of AT/RTs. This review aims to summarize the literature concerning targeted molecular therapies for pediatric AT/RTs.
| S-EPMC9218972 | biostudies-literature
Project description:BACKGROUND: To describe therapeutic approaches in children with atypical Teratoid Rhabdoid Tumours (ATRT) in France. METHODS: Observational study including all children less than 18 years old diagnosed with ATRT in France between 2009 and 2011. RESULTS: Forty seven children were included in this retrospective study. Six patients received no curative treatment while forty-one patients had a curative project. Median age was 1.5 years (range 0-16). The disease was disseminated in 10 patients. Surgical resection was complete in 21 cases. Chemotherapy was administered in 41 children. Twenty-six patients received upfront Vincristine-Methotrexate (5g/m2 x 3) with intra-thecal Methotrexate, which was stopped in eleven patients: in four cases the disease progressed and in seven cases the toxicities were manageable. Fifteen children received different chemotherapy courses and in four of them the diseases progressed. Eight patients underwent second-look surgery. Radiotherapy was administered in 17 patients at a median time of 19 weeks (13-44) after diagnosis. High-dose chemotherapy (HDCT) was given in 9 children and maintenance therapy in 5 children, starting at respectively 35 and 42 weeks after diagnosis. Median follow-up was 26 months (0.6-47). Median time for progression was 5 months. Two-years overall survival was 32% + /-8%. Median survival was 8 months. DISCUSSION: The survival rate of children with ATRT remains poor, the addition of VM is easily manageable but its benefit remains uncertain. The disease progressed mostly before radiotherapy. Future trials should focus on the delay of radiotherapy and the benefit of HDCT.
| S-EPMC4046281 | biostudies-literature
Project description:Atypical teratoid/rhabdoid tumors (AT/RT) are highly aggressive, malignant tumors and are the most common malignant brain tumor in children under 6 months of age. Currently, there is no standard treatment for AT/RT. Recent studies have reported potential anti-tumoral properties of ribavirin, a guanosine analog and anti-viral molecule approved by the Food and Drug Administration for treatment of hepatitis C. We previously demonstrated that ribavirin inhibited glioma cell growth in vitro and in vivo. Based on these results and the fact that no pre-clinical model of ribavirin in AT/RT exists, we decided to investigate the effect of ribavirin on several human AT/RT cell lines (BT12, BT16, and BT37) both in vitro and in vivo. We provide evidence that ribavirin has a significant impact on AT/RT cell growth and increases cell cycle arrest and cell death, potentially through modulation of the eIF4E and/or EZH2 pathways. Interestingly, using scratch wound and transwell Boyden chamber assays, we observed that ribavirin also impairs AT/RT cell migration, invasion, and adhesion. Finally, we demonstrate that ribavirin significantly improves the survival of mice orthotopically implanted with BT12 cells. Our work establishes that ribavirin is effective against AT/RT by decreasing tumoral cell growth and dissemination and could represent a new therapeutic option for children with this deadly disease.
| S-EPMC5814281 | biostudies-literature
Project description:Atypical teratoid rhabdoid tumor (ATRT) is a rare, highly malignant central nervous system cancer arising in infants and younger children, historically considered to be homogeneous, monogenic, and incurable. Recent use of intensified therapies has modestly improved survival for ATRT; however, a majority of patients will still succumb to their disease. While ATRTs almost universally exhibit loss of SMARCB1 (BAF47/INI1/SNF5), recent whole genome, transcriptome, and epigenomic analyses of large cohorts reveal previously underappreciated molecular heterogeneity. These discoveries provide novel insights into how SMARCB1 loss drives oncogenesis and confer specific therapeutic vulnerabilities, raising exciting prospects for molecularly stratified treatment for patients with ATRT.
| S-EPMC7339881 | biostudies-literature
Project description:Abstract Atypical Teratoid/Rhabdoid tumor (AT/RT), characterized by loss-of-function mutations in the SMARCB1 component of the SWI/SNF chromatin-remodeling complex, remains a difficult-to-treat tumor with a five-year overall survival rate of 15–45%. Proteasome inhibition (PI) has recently been opened as an avenue for cancer treatment with the FDA approval of bortezomib (BTZ) in 2003 and carfilzomib (CFZ) in 2012. We performed a drug screen using a panel of 119 FDA-approved drugs in three AT/RT cell lines, and found that both BTZ and CFZ are highly effective in vitro, producing some of the strongest growth-inhibition responses of the entire panel. We further found that these results are consistent through all three established cell lines and a freshly patient-derived tumor culture, and that the effective doses are clinically achievable. BTZ and CFZ are limited for treatment of CNS tumors due to poor blood brain barrier (BBB) penetrance. Marizomib (MRZ) is a newer proteasome inhibitor which has been shown to cross the BBB, and is already in clinical trials for adult high-grade glioma (NCT NCT02330562 and NCT02903069). Proteasome inhibition causes rapid AT/RT cell death in vitro, which may be moderately inhibited by the addition of the ROS scavenger N-acetyl cysteine, consistent with studies in leukemic and glioma contexts. MRZ has been shown to be effective in vivo in other tumor models, and confirmation of the in vivo efficacy of MRZ in an intracranial AT/RT model demonstrating the clinical applicability of PI at both low and high-burden tumor stages is ongoing.
| S-EPMC6011927 | biostudies-literature
Project description:IntroductionOverexpression of the Polycomb repressive complex 2 (PRC2) subunit Enhancer of Zeste 2 (EZH2) occurs in several malignancies, including prostate cancer, breast cancer, medulloblastoma, and glioblastoma multiforme. Recent evidence suggests that EZH2 may also have a role in rhabdoid tumors. Atypical teratoid/rhabdoid tumor (ATRT) is a rare, high-grade embryonal brain tumor that occurs most commonly in young children and carries a very poor prognosis. ATRTs are characterized by absence of the chromatin remodeling protein SMARCB1. Given the role of EZH2 in regulating epigenetic changes, we investigated the role of EZH2 in ATRT.MethodsMicroarray analysis was used to evaluate expression of EZH2 in ATRT tumor samples. We used shRNA and a chemical inhibitor of EZH2 to examine the impact of EZH2 inhibition on cell growth, proliferation, and tumor cell self-renewal.ResultsHere, we show that targeted disruption of EZH2 by RNAi or pharmacologic inhibition strongly impairs ATRT cell growth, suppresses tumor cell self-renewal, induces apoptosis, and potently sensitizes these cells to radiation. Using functional analysis of transcription factor activity, we found the cyclin D1-E2F axis to be repressed after EZH2 depletion in ATRT cells.ConclusionsOur observations provide evidence that EZH2 disruption alters cell cycle progression and may be an important new therapeutic target, particularly in combination with radiation, in ATRT.
| S-EPMC3548579 | biostudies-literature
Project description:Atypical teratoid/rhabdoid tumors (AT/RTs) are highly aggressive pediatric brain tumors characterized by the presence of rhabdoid cells and negative immunostaining for INI1 (BAF47). Histogenesis is unknown and diagnosis can be challenging because of their extreme morphological and immunophenotypic heterogeneity. Currently no signature markers other than INI1 loss have been identified. To search for possible candidate proteins of interest in AT/RTs, Affymetrix GeneChip microarrays were utilized to investigate nine AT/RTs vs. 124 other tumor samples. The most distinctive gene identified was claudin 6 (CLDN6), a key component of tight junctions. CLDN6 showed moderate or higher mRNA expression in eight of nine AT/RTs, with little to no expression in 114 of 115 other tumors. Average expression was 38-fold higher in AT/RTs vs. other samples. Immunohistochemical (IHC) staining of 33 tumor specimens found positive membrane staining in seven of seven AT/RTs, and was negative in 26 of 27 other brain tumor samples. Notably, none of the 16 medulloblastomas/primitive neuroectodermal tumors showed IHC staining for CLDN6. IHC staining results closely matched the level of mRNA expression detected by microarray. CLDN6 may be a useful positive marker to help further identify AT/RTs for diagnostic and treatment purposes.
| S-EPMC8094697 | biostudies-literature