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- Baskaran, Sathishkumar, 1988-
(författare)
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New Molecular Approaches to Glioblastoma Therapy
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Glioblastoma (GBM) is the most common high-grade brain tumor diagnosed in patients who are more than 50 years of age. The standard of care treatment is surgery, followed by radiotherapy and chemotherapy. The median life expectancy of patients is only between 12 to 15 months after receiving current treatment regimes. Hence, identification of new therapeutic compounds and gene targets are highly warranted. This thesis describes four interlinked studies to attain this goal. In study 1, we explored drug combination effects in a material of 41 patient-derived GBM cell (GC) cultures. Synergies between three compounds, pterostilbene, gefitinib, and sertraline, resulted in effective killing of GC and can be predicted by biomarkers. In study 2, we performed a large-scale screening of FDA approved compounds (n=1544) in a larger panel of GCs (n=106). By combining the large-scale drug response data with GCs genomics data, we built a novel computational model to predict the sensitivity of each compound for a given GC. A notable finding was that GCs respond very differently to proteasome inhibitors in both in-vitro and in-vivo. In study 3, we explored new gene targets by RNAi (n=1112) in a panel of GC cells. We found that loss of transcription factor ZBTB16/PLZF inhibits GC cell viability, proliferation, migration, and invasion. These effects were due to downregulation of c-MYC and Cyclin B1 after the treatment. In study 4, we tested the genomic stability of three GCs upon multiple passaging. Using molecular and mathematical analyses, we showed that the GCs undergo both systematic adaptations and sequential clonal takeovers. Such changes tend to affect a broad spectrum of pathways. Therefore, a systematic analysis of cell culture stability will be essential to make use of primary cells for translational oncology.Taken together, these studies deepen our knowledge of the weak points of GBM and provide several targets and biomarkers for further investigation. The work in this thesis can potentially facilitate the development of targeted therapies and result in more accurate tools for patient diagnostics and stratification.
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| 2. |
- Ramachandran, Mohanraj, 1988-, et al.
(författare)
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Safe and effective treatment of experimental neuroblastoma and glioblastoma using systemically administered triple microRNA-detargeted oncolytic Semliki Forest virus
- 2017
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Ingår i: Clinical Cancer Research. - : American Association for Cancer Research. - 1078-0432 .- 1557-3265. ; 23:6, s. 1519-1530
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE:Glioblastoma multiforme (GBM) and high-risk neuroblastoma are cancers with poor outcome. Immunotherapy in the form of neurotropic oncolytic viruses is a promising therapeutic strategy for these malignancies. Here we evaluate the oncolytic potential of the neurovirulent and partly interferon (IFN)-β-resistant Semliki Forest virus (SFV)-4 in GBMs and neuroblastomas. To reduce neurovirulence we constructed SFV4miRT, which is attenuated in normal CNS cells through insertion of microRNA target sequences for miR124, miR125, miR134 Experimental Design:Oncolytic activity of SFV4miRT was examined in mouse neuroblastoma and GBM cell lines and in patient-derived human glioblastoma cell cultures (HGCC). In vivo neurovirulence and therapeutic efficacy was evaluated in two syngeneic orthotopic glioma models (CT-2A, GL261) and syngeneic subcutaneous neuroblastoma model (NXS2). The role of IFN-β in inhibiting therapeutic efficacy was investigated.RESULTS:The introduction of microRNA target sequences reduced neurovirulence of SFV4 in terms of attenuated replication in mouse CNS cells and ability to cause encephalitis when administered intravenously. A single intravenous injection of SFV4miRT prolonged survival and cured 4 of 8 mice (50%) with NXS2 and 3 of 11 mice (27%) with CT-2A, but not for GL261 tumor bearing mice. In vivo therapeutic efficacy in different tumor models inversely correlated to secretion of IFN-β by respective cells upon SFV4 infection in vitro Similarly, killing efficacy of HGCC lines inversely correlated to IFN-β response and interferon-α⁄β receptor (IFNAR)-1 expression.CONCLUSIONS:SFV4miRT has reduced neurovirulence, while retaining its oncolytic potential. SFV4miRT is an excellent candidate for treatment of GBMs and neuroblastomas with low IFN-β secretion.
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