Background and working hypothesis
Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults. Despite intensive treatment, cancer recurrence is almost universal, and the median survival is only 15 months despite treatment. This is in large part due to high inter- and intra-tumor heterogeneity and rapid and diffusive invasion of tumor cells into healthy brain tissue. Moreover, aggressive infiltration enables GBM cells to actively escape surgical, chemo- and radiation therapies that cannot discriminate GBM cells from surrounding healthy cells. These numbers indicate the need to characterize mechanisms underlying GBM infiltration to uncover novel GBM-specific vulnerabilities as targets for novel therapeutic approaches.
GBM develops within a challenging microenvironment. The inflexible cranium and tumour microenvironment impose biomechanical constraints on the growing and infiltrating tumor. As such, GBM cell nuclei experience a range of very high chronic and oscillating biomechanical forces that could result in extensive cellular and DNA damage, collectively coined nuclear stress. To withstand with these pressures, tumor cells transiently or permanently change levels or activity of factors that alter nuclear biomechanical properties and deregulate force transduction into cellular response outputs such as cancer cell proliferation, infiltration (EMT), and differentiation. It is therefore tempting to speculate that targeting these alterations in biomechanical regulation would resensitize cancer cells and selectively blunt their proliferation, infiltration, and survival.
Based on our published and ongoing projects, we hypothesize that high nuclear stress and deregulated nuclear mechanotransduction are key GBM drivers that present tumor-specific vulnerabilities and unique targets for GBM treatment.
Project description
To address the above hypothesis, we are currently exploiting 3 distinct but related research projects, all centered on advanced mechanistic cell biology approaches. We are looking for 1 or 2 MSc students where the choice of project will depend on initial discussions with and research interests of the prospective MSc student(s).
Project 1. Nuclear Fragility and Mitotic exit
In our ongoing work, we have identified a molecular hub that regulates how cancer cells respond to nuclear stress, centered on a mitotic kinase and phosphatase complex network. We find that these factors regulate how the nuclear envelope dynamically associates with chromatin during and after cell division. Furthermore, we find that these factors regulate the ability of cancer cells to deal with consequences of mechanical pressures such as nuclear integrity and genome instability. In this project, we will study how this molecular hub functions to regulate nuclear stability.
Project 2. Targeting inherent nuclear biomechanical properties
By transcriptional and spatial nuclear proteomics comparison of highly infiltrating and non-infiltrating GBM cell lines, we have identified several proteins that are selectively upregulated in the nuclei of infiltrating cells. Our ongoing research indicates that these proteins control intrinsic nuclear mechanical properties such as plasticity and viscosity. In this project we will explore how these proteins enable infiltrating GBM cancer cells to withstand external pressures and migrate through their microenvironment.
Project 3. Dissecting a novel mechanotransduction pathway.
Besides intrinsic force-responsive elements (Project 2) cells utilize mechanoresponsive pathways that convert extracellular forces to intracellular signaling cascades that affect nuclear processes and cell behaviour such as infiltration. We have identified a novel mechanoresponsive signaling pathway. In this project, we will explore the regulation of this pathway, how it transmits mechanical force, and how this relies on the actin cytoskeleton, as well as on nuclear shape and integrity.
Research models and Methodology
To address questions associated with the above projects, the student will use 2D and 3D (spheroids in collagen matrixes) cancer cell culture models (predominantly Glioblastoma, as well as pancreatic cancer), with a focus on cell division, mechanical manipulation, and 3D cell invasion assays. The student will gain extensive experience with advanced live- and fixed-cell microscopy as well as image data analysis, through the MIP UiO core facility led by the main supervisor. In addition, the student will be trained in molecular genetics (lentiviral transduction, CRISPR KO) and basic molecular biology techniques (e.g. western blotting, cloning, transfections, RT-qPCR). Depending on direction of the projects and interest of the student(s), the project may include recombinant protein purification and in vitro assays (Project 1), organotypic brain slice cultures (Project 2), or proximity proteomics experiments (Project 3).
Research environment and supervision
The student(s) will be integral part of the Campsteijn lab at the section for Biochemistry, department of Molecular Medicine, Institute for Basic Medical Science, Faculty of Medicine. The group currently consists of 3 PhD students and 1 head engineer who will co-supervise the student(s). The lab and our collaborators have all the expertise needed to train and guide the student(s) and successfully implement the project. The student(s) will participate in weekly group meetings, as well as monthly meetings and activities of the Membrane Dynamics environment at the section. Through these platforms, in addition to one-on-one meetings the student(s) will develop presentation and discussion, reflection and critical interpretation, as well as experimental planning skills.
Supervisors
Main supervisor: Coen Campsteijn (IMB)
Internal supervisor: Cinzia Progida (IBV)