Atypical Rhabdoid Tumor Research Articles

ATRT-18. ALISERTIB USED IN PEDIATRIC ATRT

Abstract BACKGROUND Atypical rhabdoid tumor (ATRT) is a rare and aggressive primary CNS tumor caused by variants or deletions in the tumor suppressor gene SMARCB1 (aka INI 1). SMARCB1 targets Aurora A kinase (AURKA), an important oncoprotein of the cell cycle. AURKA dysregulation can lead to genomic instability through its oncogenic effects. Alisertib is a selective AURKA inhibitor that has been explored for treatment in various cancers, including pediatric malignancies. METHODS Retrospective chart review of five patients diagnosed with ATRT, treated with Alisertib, at Nicklaus Children’s Hospital from 2019 - 2024. RESULTS of the 5 patients; three were females and two males, with a median age at diagnosis of 2 years. Only one patient had a germline mutation while the rest had somatic mutations. Prior to starting Alisertib therapy, all five patients received chemotherapy per multiple protocols; four patients underwent focal radiation therapy, three patients underwent resection, and two patients underwent tandem autologous transplants. All five patients were treated solely with Alisertib, median dose of 60 mg/m2 PO daily. Two patients had reduced doses during therapy secondary to cytopenia. One patient completed therapy over 13 months with partial response based on imaging. One patient presented progression of disease while on therapy and for that reason treatment was stopped. Three patients continue treatment: two with only Alisertib, one using Avastin and Sirolimus concurrently. CONCLUSIONS Prognosis in patients with ATRT is usually poor given its aggressive nature and high rate of recurrence despite intervention. It is important to note that treatment of ATRT is highly individualized and typically involves a combination of therapeutic modalities. While Alisertib is one of the newest treatment options, there’s limited literature of clinical improvement in patients with ATRT using this treatment. Therefore, further research on novel treatment options is warranted for the future.

CNSC-37. ATYPICAL GERMLINE MUTATIONS AND PRIMARY CNS TUMORS: A SINGLE-CENTER CASE SERIES AND LITERATURE REVIEW

Abstract A growing spectrum of germline mutations and their association with primary CNS tumors has been described over the last decade. These germline mutations are implicated in regulation of DNA integrity and repair, telomere maintenance, and cell cycle regulation resulting in aberrant cellular proliferation and immune surveillance evasion. To date, there are no well-defined guidelines for primary CNS tumor surveillance for these patients. Moreover, the exact role of traditional chemotherapy, immunotherapy, and radiation is unclear. We present a single-institution case series of adult patients with primary CNS tumors with atypical germline mutations and literature review. The most common germline mutations encountered involved heterozygous mutations of one of the mismatch repair (MMR) genes (MSH2, PMS2, MLH1). All patients developed high-grade gliomas defined as astrocytoma or glioblastoma WHO grade 4 based on the WHO 2021 classification. Germline mutations involving RAD51C, POT1, IDH1/2, MutyH, NTHL1, PALB2, and CHEK2 were associated with gliomas of variable grades and molecular subtypes. Non-glial tumors, including atypical rhabdoid tumors, medulloblastomas, hemangioblastomas, and meningiomas were found in association with germline SMARCB1, ATM, BRCA1, and CHEK2 mutations respectively. Review of the existing literature and knowledge obtained from our case series suggests several important concepts: (1) there is an increased risk of both glioma and non-glial tumor types in several atypical germline mutations, (2) multiple risk genes or variants of unknown significance likely contribute to primary brain tumor formation, (3) germline MMR mutations associated with high-grade glioma may be MMR gene-specific with potential increased risk of resistance and/or disease progression in the presence of alkylating agents such as temozolomide, (4) several germline mutations may increase risk of secondary tumor development after radiation, and (5) the role of screening for atypical germline mutations and subsequent disease surveillance remain unanswered.

Abstract 1831: 9-ING-41, a glycogen synthase kinase 3B inhibitor targets TP53 in pediatric brain tumors ATRT and ETMR

Abstract Purpose: The study aims to determine the activity of the blood brain barrier permeable glycogen synthase kinase 3B (GSK3B) inhibitor, 9-ING-41, in pediatric brain tumors: embryonal tumor with multilayered rosettes (ETMR) and atypical rhabdoid tumor (ATRT). Methods: ETMR cell line, BT183, was grown in ultralow attachment flasks and ATRT cell lines: ATRT-7316-2187, ATRT-787197, and CHLA02 were grown in suspension flasks. Cells were treated with 9-ING-41 at dose range (0-20µM). After 24 and 48 hours of 9-ING-41 cells were analyzed by western blot. After 72 hours of 9-ING-41 cell viability was assessed with Cell Titer Glo 2.0 and IC50s were analyzed by GraphPad. RNA seq was performed on cells after 12, 24, and 48 hours of 9-ING-41 treatment. Total RNA was isolated with miRNeasy Mini Kit. RNA integrity was evaluated by an Agilent 2100 Bioanalyzer profile. rRNA was selectively depleted by employing RiboZero Globin. Next generation sequencing libraries were prepared using an Illumina TruSeq Stranded Total RNA kits. Read mapping was performed using STAR in BaseSpace. DESeq2 was used for normalization and differential expression analysis. Ingenuity Pathway Analysis was performed. Results: The IC50s of 9-ING-41 in the cell lines BT183, CHLA02-ATRT, ATRT-787197, and ATRT-2187 are 145.5nM, 481.2nM, 503.1nM, and 528.3nM, respectively. In BT183 cells treated with 150nM 9-ING-41 for 48 hours, XIAP decreased significantly by 55% and cleaved caspase 3 increased significantly by 29-fold, quantified by densitometry. In addition, western blot showed a decrease in LIN28A and an increase in TP53 protein levels. RNA-seq data show an increase in the p53 signaling pathway in the ETMR BT183 cell line with z-scores of 2.53 and 3 (p=3.73x10-13 and 2.35x10-14) after 12 and 24 hours of 150nM 9-ING-41, respectively. In ATRT-787197 cells p53 signaling increased with z-scores of 1.0 and 2.236 (p=2.62x10-8 and 2.89x10-5) after 24 and 48 hours of 400nM 9-ING-41, respectively. RNA seq data also show the ability of 9-ING-41 to significantly increase the expression of CDK inhibitor, CDKN1A, and pro-apoptotic genes BBC3, DRAM1, and BAX in ETMR and ATRT while significantly decreasing stemness associated genes: SMO and GLI1 in ETMR. Conclusions: 9-ING-41 decreases ETMR and ATRT cell viability at clinically relevant concentrations and these doses increase the p53 pathway and induce apoptosis while reducing the expression of stemness associated genes. Citation Format: Jason L. Haw, Elizabeth M. Moore, Kimberly McKinney, Karl Dykema, Abhinav Nagulapally, Nury Steuerwald, Giselle S. Sholler. 9-ING-41, a glycogen synthase kinase 3B inhibitor targets TP53 in pediatric brain tumors ATRT and ETMR [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1831.

A phase I/II study of atezolizumab in pediatric and young adult patients with refractory/relapsed solid tumors (iMATRIX-Atezolizumab).

10524 Background: Atezolizumab targets programmed death-ligand 1 (PD-L1), leading to enhanced anticancer T-cell response. The iMATRIX-Atezolizumab study (phase I/II, multicenter, open-label; NCT02541604) assessed the safety, pharmacokinetics (PK) and preliminary activity of atezolizumab in pediatric/young adult patients with refractory/relapsed solid tumors. Methods: Patients aged < 30 years with refractory/relapsed non-central nervous system solid tumors received atezolizumab every 3 weeks until loss of clinical benefit ( < 18 years old, 15mg/kg [maximum dose 1200mg]; ≥18 years old, 1200mg). Safety/PK were assessed across tumor types and initial response was assessed by tumor-type cohorts after approximately 10 patients in each cohort had been treated. Results: As of July 19 2016, 74 patients (median age 14 years; range 2–29) were enrolled: osteosarcoma, n = 12; Ewing sarcoma, n = 11; neuroblastoma, n = 11; rhabdomyosarcoma (RMS), n = 10; non-RMS soft tissue sarcoma, n = 10; Wilms tumor, n = 6; Hodgkin lymphoma (HL), n = 5; non-HL, n = 1; other tumor types, n = 8. PK data (n = 48) were similar to that in adults (geometric mean Cmin, µg/mL [cycle 2, day 1, pre-dose]: 53.6 [2– < 6 years old]; 54.1 [6– < 12 years old]; 62.0 [12– < 18 years old]; 68.0 [adult]). Most tumors, except HL, had < 1% (score 0) tumor cell [TC]/tumor-infiltrating immune cell (IC) PD-L1 expression with overall TC/IC-positive expression rates (≥1%, score 1–3) of 7% and 10%, respectively. All available HL samples had ≥5% (score 2–3) TC/IC PD-L1 expression. 67/71 patients who received atezolizumab (median cycles 2; range 1–10) had ≥1 adverse event (AE; mainly immune-related grade 1–2); 17 patients (24%) had treatment-related grade 3–4 AEs. One AE (grade 3 transaminase increase) led to study drug discontinuation. Common AEs were pyrexia (37%), fatigue (34%) and constipation (32%). 2/5 patients with HL had a partial response (PR); the only patient with atypical rhabdoid tumor (RT) had an unconfirmed PR. Conclusions: The PK and safety profile of atezolizumab in pediatric and young adult patients is similar to that in adults. Preliminary antitumor activity was seen in HL and RT; new cohorts are planned in RT and atypical teratoid RT. Clinical trial information: NCT02541604.

Atypical rhabdoid tumor of lateral ventricle: Report of an unusual tumor

Supratentorial atypical teratoid rhabdoid tumors (AT/RTs) of infancy and childhood are rare, highly malignant neoplasms, most common in the first 2 years of life. In spite of multiple treatment regimens consisting of surgical resection, radiation therapy, and multi-agent chemotherapy, the prognosis is very poor. The majority of these tumors are located in the cerebellum, cerebellopontine angle, pineal gland, spinal cord, and the suprasellar region; supratentorial location is relatively uncommon, and the intraventricular location is extremely rare. We report a rare case of AT/RT arising in the lateral ventricle in a 4-year-old patient.

A standardized and reproducible protocol for serum-free monolayer culturing of primary paediatric brain tumours to be utilized for therapeutic assays.

In vitro cultured brain tumour cells are indispensable tools for drug screening and therapeutic development. Serum-free culture conditions tentatively preserve the features of the original tumour, but commonly comprise neurosphere propagation, which is a technically challenging procedure. Here, we define a simple, non-expensive and reproducible serum-free cell culture protocol for establishment and propagation of primary paediatric brain tumour cultures as adherent monolayers. The success rates for establishment of primary cultures (including medulloblastomas, atypical rhabdoid tumour, ependymomas and astrocytomas) were 65% (11/17) and 78% (14/18) for sphere cultures and monolayers respectively. Monolayer culturing was particularly feasible for less aggressive tumour subsets, where neurosphere cultures could not be generated. We show by immunofluorescent labelling that monolayers display phenotypic similarities with corresponding sphere cultures and primary tumours, and secrete clinically relevant inflammatory factors, including PGE2, VEGF, IL-6, IL-8 and IL-15. Moreover, secretion of PGE2 was considerably reduced by treatment with the COX-2 inhibitor Valdecoxib, demonstrating the functional utility of our newly established monolayer for preclinical therapeutic assays. Our findings suggest that this culture method could increase the availability and comparability of clinically representative in vitro models of paediatric brain tumours, and encourages further molecular evaluation of serum-free monolayer cultures.

Abstract 2491: High-dose acetaminophen with N-acetylcysteine rescue enhances the efficacy of cisplatin chemotherapy

Abstract Acetaminophen (AAP) has been shown to enhance cisplatin (CDDP) cytotoxicity in hepatoblastoma cell lines. Further, one published case report demonstrated clinical efficacy of administering acetaminophen in conjunction with cisplatin and followed 6 hours later with n-acetylcysteine (NAC) rescue. In this study, atypical rhabdoid tumor (ATRT) and germinoma cells were treated with CDDP and AAP with or without NAC rescue. We then evaluated the cells with western blots for cleaved PARP and caspase 3 to demonstrate effects on apoptosis. Further, MTS assays were performed to evaluate cell viability of treated cells. To evaluate the effects of the various treatments on oxidative stress, dihydroethidium (DHE) and 2′,7′-dichlorofluorescin (DCFH) assays were performed to test for superoxide and hydrogen peroxide levels, respectively. It was demonstrated that AAP enhances CDDP cell kill and apoptosis in germinoma and ATRT cell lines. Further, both AAP and CDDP, independently and together, cause increased oxidative stress as measured by DHE and DCFE, but this oxidative stress is only reversed by NAC in the DCFE assay. This makes sense because NAC, a glutathione precursor, detoxifies peroxide but not superoxide. Further, our group has learned of five previously unpublished patients with recurrent liver tumors (hepatocellular carcinoma and hepatoblastoma) treated with AAP and CDDP with delayed NAC rescue. All patients tolerated the treatment well. Two of the five patients responded to the treatment, suggesting the potential of this approach. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2491. doi:1538-7445.AM2012-2491

Primary Intracranial Extra-Axial and Supratentorial Atypical Rhabdoid Tumor

An atypical teratoid/rhabdoid tumor of the central nervous system is an aggressive infantile embryonal neoplasm, usually presenting as an infratentorial and intraparenchymatous lesion. We report on magnetic resonance imaging findings of a 22-month-old boy with a biopsy-proven primary rhabdoid tumor, presenting as a single intracranial supratentorial extra-axial mass. Based on the patient's age and imaging features (perfusion, diffusion magnetic resonance imaging, and magnetic resonance spectroscopy), a diagnosis of atypical teratoid/rhabdoid tumor was more accurate than diagnoses of meningioma and primitive neuroectodermal tumor. Although this entity is relatively rare, it should be considered in the differential diagnosis of dural-based, space-occupying central nervous system lesions.

INTRAVENTRICULAR TEICOPLANIN

Following craniotomy for an atypical rhabdoid tumour of the posterior cranial fossa, a fourteen-month-old boy developed a ventriculitis with methicillin resistant Staphylococcus epidermidis (MRSE) which is associated with the use of a ventriculoperitoneal shunt. Treatment with intravenous vancomycin resulted in a severe allergic skin reaction. Substitution with intravenous teicoplanin resulted in negative blood culture and MRSE ventriculitis was successfully eradicated with concomitant use of intraventricular teicoplanin. No signs of recurrent infection or adverse events occurred. Intraventricular teicoplanin is safe and effective for the treatment of staphylococcal neurosurgical shunt infections.

Comparison of myelography with CT follow‐up versus gadolinium MRI for subarachnoid metastatic disease in children

We evaluated 17 children with primary intracranial neoplasms for subarachnoid metastatic disease (SAMD) using myelography with computed tomographic follow-up (Myelo + CT) and cerebrospinal fluid (CSF) histopathologic examination, as well as magnetic resonance imaging with gadolinium DTPA (MRI + Gd), between December 1988 and December 1989. There were 12 boys, and the median age was 5.7 years (range, 0.8 to 21.8 years). Tumor histology included 8 primitive neuroectodermal tumors (PNETs), 3 ependymomas, 2 low-grade astrocytomas, 1 anaplastic astrocytoma, 1 glioblastoma multiforme, 1 atypical rhabdoid tumor, and 1 malignant fibrous histiocytoma. Thirteen tumors originated in the posterior fossa, 2 were supratentorial, and 2 were in the spinal cord. The median interval between the 2 diagnostic tests was 2 days. MRI + Gd was positive in 11 (65%), Myelo + CT in 8 (47%), and CSF in 5 (29%) cases. MRI + Gd was superior in delineating spinal cord nodules and "sugar coating" whereas Myelo + CT more readily revealed nerve root sleeve filling defects. There was no case in which Myelo + CT was positive that MRI + Gd did not reveal SAMD. MRI + Gd is a safe, noninvasive test that should be used as the initial imaging modality for the presence of SAMD.