Biology subjects

Forsberg-Nilsson, K.

Publications and source records attributed to Forsberg-Nilsson, K..

7 recordsLinked to original sources

bioRxiv2024

Lamins regulate nuclear mechanics and shape to control glioblastoma cell proliferation, migration and invasion

Glioblastoma (GBM) is known as the most aggressive brain tumor and is characterized by a high heterogeneity and a median patient survival time around 15 months. Phenotyping based on cell mechanics is increasingly recognized as a potential prognostic marker for tumor aggressiveness. We have previously shown that cell and nuclear mechanical properties vary between different grades of gliomas and may be used to differentiate between GBM of different aggressiveness. Here, we find that the levels of lamin proteins can serve as an indicator of GBM aggressiveness. In patient-derived GBM cell lines, we found that cells from different GBM express different lamin levels. Nuclear size correlates positively with the ratio between lamin A and lamin B1 while nuclear stiffness increases with the levels of both lamin A and lamin B1. A simple mechanical model suggests that lamin A and lamin B1 act like springs in series. We also show that cells proliferate faster in GBM cell lines expressing higher lamin A levels. Downregulating lamin A expression in these cells reverse the aggressive phenotype. In contrast with breast cancer cells for which reduced lamin A levels favor cell migration in a confined environment, increased levels of lamin A may facilitate the invasion of more aggressive GBM cell lines in the soft environment of the brain. Furthermore, since nuclear deformation is a hallmark of malignancy in cancer cells, our results suggest that nuclear shape and mechanics may serve as prognosis biomarkers for GBM.

biophysics↗

bioRxiv2024

Characterizing and targeting glioblastoma neuron-tumor networks with retrograde tracing

Glioblastomas are invasive brain tumors with high therapeutic resistance. Neuron-to-glioma synapses have been shown to promote glioblastoma progression. However, a characterization of tumor-connected neurons has been hampered by a lack of technologies. Here, we adapted retrograde tracing using rabies viruses to investigate and manipulate neuron-tumor networks. Glioblastoma rapidly integrated into neural circuits across the brain engaging in widespread functional communication, with acetylcholinergic neurons driving glioblastoma invasion. We uncovered patient-specific and tumor cell state-dependent differences in synaptogenic gene expression associated with neuron-tumor connectivity and subsequent invasivity. Importantly, radiotherapy enhanced neuron-tumor connectivity by increased neuronal activity. In turn, simultaneous neuronal activity inhibition and radiotherapy showed increased therapeutic effects, indicative of a role for neuron-to-glioma synapses in contributing to therapeutic resistance. Lastly, rabies-mediated genetic ablation of tumor-connected neurons halted glioblastoma progression, offering a viral strategy to tackle glioblastoma. Together, this study provides a framework to comprehensively characterize neuron-tumor networks and target glioblastoma.

cancer biology↗

bioRxiv2023

Title: Leveraging Base Pair Mammalian Constraint to Understand Genetic Variation and Human Disease

Although thousands of genomic regions have been associated with heritable human diseases, attempts to elucidate biological mechanisms are impeded by a general inability to discern which genomic positions are functionally important. Evolutionary constraint is a powerful predictor of function that is agnostic to cell type or disease mechanism. Here, single base phyloP scores from the whole genome alignment of 240 placental mammals identified 3.5% of the human genome as significantly constrained, and likely functional. We compared these scores to large-scale genome annotation, genome-wide association studies (GWAS), copy number variation, clinical genetics findings, and cancer data sets. Evolutionarily constrained positions are enriched for variants explaining common disease heritability (more than any other functional annotation). Our results improve variant annotation but also highlight that the regulatory landscape of the human genome still needs to be further explored and linked to disease.

genomics↗

bioRxiv2022

Using evolutionary constraint to define novel candidate driver genes in medulloblastoma

Current knowledge of cancer genomics is biased against non-coding mutations. Here, we use whole genome sequencing data from pediatric brain tumors, combined with evolutionary constraint inferred from 240 mammals to identify genes enriched in non-coding constraint mutations (NCCMs). We compare medulloblastoma (MB, malignant) to pilocytic astrocytoma (PA, benign) and find drastically different NCCM frequencies between the two. In PA, a high NCCM frequency only affects the BRAF locus, while in MB, >500 genes have high levels of NCCMs. Intriguingly, many genes are associated with different age of onset, such as HOXB1 in young patients and NUAK1 in adult patients. Our analysis points to different molecular pathways in different patient groups. These novel candidate driver genes may assist patient stratification in MB and may be useful for treatment options. One-Sentence SummaryNon-coding constraint mutations implicate novel candidate genes to stratify medulloblastoma by age and subgroups.

cancer biology↗

bioRxiv2021

PTEN inhibits AMPK to control collective migration

PTEN is one of the most frequently mutated tumor suppressor gene in cancer. PTEN is generally altered in invasive cancers such as glioblastomas, but its function in collective cell migration and invasion is not fully characterized. Herein, we report that the loss of PTEN increases cell speed during collective migration of non-tumourous cells both in vitro and in vivo. We further show that loss of PTEN promotes LKB1-dependent phosphorylation and activation of the major metabolic regulator AMPK. In turn AMPK increases VASP phosphorylation, reduces VASP localization at cell-cell junctions and decreases the interjunctional transverse actin arcs at the leading front, provoking a weakening of cell-cell contacts and increasing migration speed. Targeting AMPK activity not only slows down PTEN-depleted cells, it also limits PTEN-null glioblastoma cell invasion, opening new opportunities to treat glioblastoma lethal invasiveness.

cell biology↗

bioRxiv2019

Live detection of neural stem and glioblastoma cells by an oligothiophene derivative

Here we report a luminescent conjugated oligothiophene (LCO), named p-HTMI, for non-invasive and non-amplified real-time detection of live human patient-derived glioblastoma (GBM) cells and embryonic neural stem cells (NSCs). While p-HTMI stained only a small fraction of other cell types investigated, the mere addition of p-HTMI to the cell culture resulted in efficient detection of NSCs or GBM cells from rodents and humans within minutes. p-HTMI is functionalized with a methylated imidazole moiety resembling the side chain of histidine/histamine, and non-methylated analogues were not functional. p-HTMI were readily able to detect a subpopulation of human cells in vivo in mouse brain sections with tumors developed from orthotopically transplanted patient-derived GBM cells. Cell sorting experiments of human GBM cells demonstrated that p-HTMI labeled the same population as CD271, a proposed marker for stem cell-like cells and rapidly migrating cells in glioblastoma. Our results suggest that the LCO p-HTMI is a versatile tool for immediate and selective detection of subpopulations of neural stem and glioma cells.

bioengineering↗

bioRxiv2019

ADAMDEC1 maintains a novel growth factor signaling loop in cancer stem cells

Glioblastomas (GBM) are lethal brain tumors where poor outcome is attributed to cellular heterogeneity, therapeutic resistance, and a highly infiltrative nature. These characteristics are preferentially linked to GBM cancer stem cells (GSCs), but how GSCs maintain their stemness is incompletely understood and the subject of intense investigation. Here, we identify a novel signaling loop that induces and maintains GSCs. This loop consists of an atypical metalloproteinase, a disintegrin and metalloproteinase domain-like protein decysin 1 (ADAMDEC1), secreted by GSCs. ADAMDEC1 rapidly solubilizes fibroblast growth factor-2 (FGF2) to stimulate FGF receptor 1 (FGFR1) expressed on GSCs. This signaling axis induces upregulation of Zinc finger E-box-binding homeobox 1 (ZEB1) that regulates ADAMDEC1 expression, creating a positive feedback loop. Genetic or pharmacological targeting of components of this axis attenuates self-renewal and tumor growth. These findings reveal a new signaling axis for GSC maintenance and highlight ADAMDEC1 and FGFR1 as potential therapeutic targets in GBM. Statement of SignificanceCancer stem cells (CSC) drive tumor growth in many cancers including glioblastoma. We identified a novel sheddase, a disintegrin and metalloproteinase domain-like protein decysin 1, that initiates a fibroblast growth factor autocrine loop to promote stemness in CSCs. This loop can be targeted to reduce glioblastoma growth.

cancer biology↗