A pinboard by
this curator

Medulloblastoma: a blast from the past. That's the dream

As a graduate student, I've found that researchers of medulloblastoma are working fast and furious. This is a good thing! This is your one stop shop to get the newest research and clinical news in the MB world. Now you can even keep up with Sonic the Hedgehog!!! (guys...see what I did there...)


Functional expression of calcium-permeable Canonical Transient Receptor Potential 4-containing channels promotes migration of medulloblastoma cells.

Abstract: Aberrant intracellular Ca(2+) signalling contributes to the formation and progression of a range of distinct pathologies including cancers. Rises in intracellular Ca(2+) concentration occur in response to Ca(2+) influx through plasma membrane channels and Ca(2+) release from intracellular Ca(2+) stores, which can be mobilised in response to activation of cell surface receptors. OGR1 (Ovarian cancer G protein coupled Receptor 1, aka GPR68) is a proton-sensing Gq -coupled receptor that is most highly expressed in cerebellum. Medulloblastoma (MB) is the most common paediatric brain tumour that arises from cerebellar precursor cells. We find that nine distinct human MB samples all express OGR1. In both normal granule cells and the transformed human cerebellar granule cell line DAOY, OGR1 promotes expression of the proton-potentiated member of the Canonical Transient Receptor Potential (TRPC) channel family, TRPC4. Consistent with a role for TRPC4 in MB, we find that all MB samples also express TRPC4. In DAOY cells, activation of TRPC4-containing channels resulted in large Ca(2+) influx and enhanced migration, while in normal cerebellar granule (precursor) cells and MB cells not derived from granule precursors, only small levels of Ca(2+) influx and no enhanced migration was observed. Our results suggest that OGR1-dependent increases in TRPC4 expression may favour formation of highly Ca(2+) -permeable TRPC4-containing channels that promote transformed granule cell migration. Increased motility of cancer cells is a prerequisite for cancer invasion and metastasis, and our findings may point towards a key role for TRPC4 in progression of certain types of MB. This article is protected by copyright. All rights reserved.

Pub.: 20 Jun '17, Pinned: 20 Jun '17

A phase I study of single-agent perifosine for recurrent or refractory pediatric CNS and solid tumors.

Abstract: The PI3K/Akt/mTOR signaling pathway is aberrantly activated in various pediatric tumors. We conducted a phase I study of the Akt inhibitor perifosine in patients with recurrent/refractory pediatric CNS and solid tumors. This was a standard 3+3 open-label dose-escalation study to assess pharmacokinetics, describe toxicities, and identify the MTD for single-agent perifosine. Five dose levels were investigated, ranging from 25 to 125 mg/m2/day for 28 days per cycle. Twenty-three patients (median age 10 years, range 4-18 years) with CNS tumors (DIPG [n = 3], high-grade glioma [n = 5], medulloblastoma [n = 2], ependymoma [n = 3]), neuroblastoma (n = 8), Wilms tumor (n = 1), and Ewing sarcoma (n = 1) were treated. Only one DLT occurred (grade 4 hyperuricemia at dose level 4). The most common grade 3 or 4 toxicity at least possibly related to perifosine was neutropenia (8.7%), with the remaining grade 3 or 4 toxicities (fatigue, hyperglycemia, fever, hyperuricemia, and catheter-related infection) occurring in one patient each. Pharmacokinetics was dose-saturable at doses above 50 mg/m2/day with significant inter-patient variability, consistent with findings reported in adult studies. One patient with DIPG (dose level 5) and 4 of 5 patients with high-grade glioma (dose levels 2 and 3) experienced stable disease for two months. Five subjects with neuroblastoma (dose levels 1 through 4) achieved stable disease which was prolonged (≥11 months) in three. No objective responses were noted. In conclusion, the use of perifosine was safe and feasible in patients with recurrent/refractory pediatric CNS and solid tumors. An MTD was not defined by the 5 dose levels investigated. Our RP2D is 50 mg/m2/day.

Pub.: 06 Jun '17, Pinned: 20 Jun '17

Phase I study of oral sonidegib (LDE225) in pediatric brain and solid tumors and a phase II study in children and adults with relapsed medulloblastoma.

Abstract: Sonidegib (LDE225) is a potent, selective Hedgehog (Hh) inhibitor of SMOOTHENED. This study explored the safety and pharmacokinetics (PK) of sonidegib in children with relapsed/recurrent tumors followed by a phase II trial in pediatric and adult patients with relapsed medulloblastoma (MB) to assess tumor response.Pediatric patients aged ≥1-<18 years were included according to a Bayesian design starting at 372mg/m2 of continuous once daily oral sonidegib. Tumor samples were analyzed for Hh pathway activation using a validated 5-gene Hh signature assay. In phase II, pediatric patients were treated at the recommended phase II dose (RP2D) while adults received 800mg daily.Sixteen adult (16 MB) and 60 pediatric (39 MB, 21 other) patients with an age range of 2-17 years were enrolled. The RP2D of sonidegib in pediatric patients was established at 680mg/m2 once daily. The phase II study was closed prematurely. The 5-gene Hh signature assay showed that the 4 complete responders (2 pediatric and 2 adult) and 1 partial responder (adult), all had Hh‑activated tumors, while 5 patients with activated Hh had either stable disease (n=3) or progressive disease (n=2). No patients with Hh-negative signatures (n=50) responded. The safety profile for pediatric patients was generally consistent with the one established for adult patients; however, growth plate changes were observed in pre-pubertal pediatric patients'.Sonidegib was well tolerated and the RP2D in pediatric patients was 680mg/m2 once daily. Five of the 10 MB patients with activated Hh pathway demonstrated complete or partial responses.

Pub.: 13 Jun '17, Pinned: 20 Jun '17

Fluorescence Lifetime Imaging Microscopy, a Novel Diagnostic Tool for Metastatic Cell Detection in the Cerebrospinal Fluid of Children with Medulloblastoma.

Abstract: In pediatric brain tumours, dissemination of malignant cells within the central nervous system confers poor prognosis and determines treatment intensity, but is often undetectable by imaging or cytology. This study describes the use of fluorescence lifetime (FLT) imaging microscopy (FLIM), a novel diagnostic tool, for detection of metastatic spread. The study group included 15 children with medulloblastoma and 2 with atypical teratoid/rhabdoid tumour. Cells extracted from the tumour and the cerebrospinal fluid (CSF) 2 weeks postoperatively and repeatedly during chemo/radiotherapy were subjected to nuclear staining followed by FLT measurement and cytological study. Control CSF samples were collected from patients with infectious/inflammatory disease attending the same hospital. Median FLT was prolonged in tumour cells (4.27 ± 0.28 ns; P < 2.2*10(-16)) and CSF metastatic cells obtained before chemo/radiotherapy (6.28 ± 0.22 ns; P < 2.2*10(-16)); normal in inflammatory control cells (2.6 ± 0.04 ns) and cells from children without metastasis before chemo/radiotherapy (2.62 ± 0.23 ns; P = 0.858) and following treatment (2.62 ± 0.21 ns; P = 0.053); and short in CSF metastatic cells obtained after chemo/radiotherapy (2.40 ± 0.2 ns; P < 2.2*10(-16)). FLIM is a simple test that can potentially identify CSF spread of brain tumours. FLT changes in accordance with treatment, with significant prolonged median values in tumours and metastases. More accurate detection of metastatic cells may guide personalised treatment and improve the therapeutic outcome.

Pub.: 18 Jun '17, Pinned: 20 Jun '17