Measuring performance status in pediatric patients with brain tumors--experience of the HIT-GBM-C protocol

Musashi1 enhances chemotherapy resistance of pediatric glioblastoma cells in vitro

BACKGROUND

Glioblastoma (GBM) is the most aggressive form of glioma in adults and children and is associated with very poor prognosis. Pediatric tumors are biologically distinct from adult GBM and differ in response to current GBM treatment protocols. Regarding pediatric GBM, new drug combinations and the molecular background of chemotherapy effects need to be investigated, in order to increase patient survival outcome.

METHODS

The expression of the RNA-binding protein Musashi1 (MSI1) in pediatric glioma samples of different WHO tumor grades was investigated on the protein (immunohistochemistry) and on the RNA level (publicly accessible RNA sequencing dataset). The impact of the chemotherapeutic temozolomide (TMZ) in combination with valproic acid (VPA) was tested in two pediatric glioblastoma-derived cell lines. The supportive effect of MSI1 expression against this treatment was investigated via transient knockdown and protein overexpression.

RESULTS

MSI1 expression correlates with pediatric high-grade glioma (HGG). The combination of TMZ with VPA significantly increases the impact of drug treatment on cell viability in vitro. MSI1 was found to promote drug resistance to the combined treatment with TMZ and VPA.

CONCLUSION

MSI1 expression is a potential marker for pediatric HGG and increases chemoresistance. Inhibition of MSI1 might lead to an improved patient outcome and therapy response.

Pediatric high grade glioma of the spinal cord: results of the HIT-GBM database

Little is known about pediatric spinal cord high grade gliomas (SCHGG) beyond their dismal prognosis. Here, we analyzed the HIT-GBM(®) database for the influence of surgical resection on survival. Between 1991 and 2010 the HIT-GBM group collected data from European children diagnosed with high grade glioma. Patients with the following inclusion criteria were analyzed in this study: astrocytic histology, WHO grade III or IV, age at diagnosis <18 years, and tumor localized to the spinal cord. 28 patients (mean age 11.28 years, 14 male) with primary SCHGG were identified. The tumor sizes were measured by the span across adjacent vertebrae and varied greatly (range: 1-20, median: 4). Histology was classified as WHO grade III in 15 and grade IV in 13 tumors. Of note, the four largest tumors identified were WHO grade III. Surgery was classified as complete resection (n = 6), subtotal resection (STR) (n = 7), partial resection (n = 12) or biopsy only (n = 3). 27 patients received chemotherapy, 22 of which also received radiation. With the mean follow-up time of 2.88 (SD ± 2.95) years, 14 patients were still alive resulting in a median overall survival of 2.5 years (SE ± 1.6). The positive prognostic indicators for overall survival were: age younger than 5 years (P = 0.047), WHO grade III (P = 0.046), absence of necrosis (P = 0.025) and gross total resection (GTR) (P = 0.012). The prognosis of SCHGG might not be as miserable as generally assumed. GTR is of benefit. Larger data sets and meta-analysis are necessary to identify patient sub-groups.