Multimodal therapy of glioblastoma (GBM) reveals inter-individual variability in terms of treatment outcome. Here, we examined whether a miRNA signature can be defined for the a priori identification of patients with particularly poor prognosis.FFPE sections from 36 GBM patients along with overall survival follow-up were collected retrospectively and subjected to miRNA signature identification from microarray data. A risk score based on the expression of the signature miRNAs and cox-proportional hazard coefficients was calculated for each patient followed by validation in a matched GBM subset of TCGA. Genes potentially regulated by the signature miRNAs were identified by a correlation approach followed by pathway analysis.A prognostic 4-miRNA signature, independent of MGMT promoter methylation, age, and sex, was identified and a risk score was assigned to each patient that allowed defining two groups significantly differing in prognosis (p-value: 0.0001, median survival: 10.6 months and 15.1 months, hazard ratio = 3.8). The signature was technically validated by qRT-PCR and independently validated in an age- and sex-matched subset of standard-of-care treated patients of the TCGA GBM cohort (n=58). Pathway analysis suggested tumorigenesis-associated processes such as immune response, extracellular matrix organization, axon guidance, signalling by NGF, GPCR and Wnt. Here, we describe the identification and independent validation of a 4-miRNA signature that allows stratification of GBM patients into different prognostic groups in combination with one defined threshold and set of coefficients that could be utilized as diagnostic tool to identify GBM patients for improved and/or alternative treatment approaches.

Recently, we reported that the loss of a telomeric region of chromosome 8 in Chinese Hamster Ovary (CHO) cells correlates with higher recombinant productivities. New cell lines lacking this region, called CHO-C8DEL, showed several advantages during cell line generation and for the production of recombinant proteins (Ritter et al., 2016, Biotechnol Bioeng). Here, we performed knock-down and knock-out experiments of genes located within this telomeric region of chromosome 8 to identify the genes causing the observed phenotypes of CHO-C8DEL cell lines. We present evidence that loss or reduced expression of the gene C12orf35 is responsible for higher productivities and shorter recovery times during selection pressure. These effects are mediated by increased levels of mRNA of the exogenes heavy chain (HC) and light chain (LC) as well as dihydrofolate reductase (DHFR) and neomycin phosphotransferase (Neo) during the stable expression of antibodies. Biotechnol. Bioeng. 2016;113: 2433-2442. © 2016 Wiley Periodicals, Inc.

Background The potential benefit of risk stratification using a 4-miRNA signature in combination with MGMT promoter methylation in IDH1/2 wild-type glioblastoma patients was assessed. Methods Primary tumors from 102 patients with comparable treatment from the LMU Munich (n=37), the University Hospital Düsseldorf (n=33) and The Cancer Genome Atlas (TCGA, n=32) were included. Risk groups were built using expressions of hsa-let-7a-5p, hsa-let-7b-5p, hsa-miR-615-5p and hsa-miR-125a-5p to assess prognostic performance in overall survival (OS). MGMT promoter methylation and age were considered as cofactors. Integrated miRNA, DNA-Methylome and transcriptome analysis was used to explore the functional impact of signature miRNAs. Results The 4-miRNA signature defined high-risk (n=46, med. OS: 15.8 months) and low-risk patients (n=56, med. OS: 20.7 months; univariable Cox proportional hazard analysis: HR: 1.8, 95%-CI: 1.14-2.83, p=0.01). The multivariable Cox-PH-model including the 4-miRNA signature (p=0.161), MGMT promoter methylation (p<0.001) and age (p=0.034) significantly predicted OS (Log-rank-p < 0.0001). Likewise to clinical routine, analysis was performed for younger (≤60 years, n=50, med. OS: 20.2 months) and older patients (>60 years, n=52, med. OS: 15.8) separately. In younger patients, the 4-miRNA signature had prognostic value (HR: 1.92, 95%-CI 0.93-3.93, p=0.076). Particularly, younger, MGMT methylated, 4-miRNA signature low-risk patients (n=18, med. OS: 37.4 months) showed significantly improved survival, compared to other younger patients (n=32, OS 18.5 months; HR: 0.33, 95%-CI 0.15-0.71, p=0.003). Integrated data analysis revealed 4-miRNA signature-associated genes and pathways. Conclusions The prognostic 4-miRNA signature in combination with MGMT promoter methylation improved risk stratification with potential for therapeutic sub-stratification especially of younger patients.

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