0000000000005396
AUTHOR
Anne Régnier-vigouroux
Evaluation of consistency in spheroid invasion assays
Multicellular tumor spheroids embedded in a matrix represent invaluable tools to analyze cell invasion. Spheroid sizes and invasiveness are the main observables easily measurable to evaluate effects of biological or pharmaceutical manipulations on invasion. They largely account for these 3-D platforms variability, leading to flaws in data interpretation. No method has been established yet that characterizes this variability and guarantees a reliable use of 3-D platforms. Spheroid initial/end sizes and invasiveness were systematically analyzed and compared in spheroids of U87MG cells generated by three different methods and embedded at different times in a collagen matrix. A normality test w…
MYC dosage compensation is mediated by miRNA-transcription factor interactions in aneuploid cancer
SummaryWe hypothesize that dosage compensation of critical genes arises from systems-level properties for cancer cells to withstand the negative effects of aneuploidy. We identified several candidate genes in cancer multi-omics data and developed a biocomputational platform to construct a mathematical model of their interaction network with miRNAs and transcription factors, where the property of dosage compensation emerged for MYC and was dependent on the kinetic parameters of its feedback interactions with three micro-RNAs. These circuits were experimentally validated with a novel genetic tug-of-war technique by overexpressing an exogenous MYC leading to over-expression of the three microR…
MYC dosage compensation is mediated by miRNA-transcription factor interactions in aneuploid cancer
Summary We hypothesize that dosage compensation of critical genes arises from systems-level properties for cancer cells to withstand the negative effects of aneuploidy. We identified several candidate genes in cancer multiomics data and developed a biocomputational platform to construct a mathematical model of their interaction network with micro-RNAs and transcription factors, where the property of dosage compensation emerged for MYC and was dependent on the kinetic parameters of its feedback interactions with three micro-RNAs. These circuits were experimentally validated using a genetic tug-of-war technique to overexpress an exogenous MYC, leading to overexpression of the three microRNAs …
MiR-144 overexpression as a promising therapeutic strategy to overcome glioblastoma cell invasiveness and resistance to chemotherapy
Abstract Glioblastoma (GB) is the most aggressive and common form of primary brain tumor, characterized by fast proliferation, high invasion, and resistance to current standard treatment. The average survival rate post-diagnosis is only of 14.6 months, despite the aggressive standard post-surgery treatment approaches of radiotherapy concomitant with chemotherapy with temozolomide. Altered cell metabolism has been identified as an emerging cancer hallmark, including in GB, thus offering a new target for cancer therapies. On the other hand, abnormal expression levels of miRNAs, key regulators of multiple molecular pathways, have been correlated with pathological manifestations of cancer, such…
High resistance to X-rays and therapeutic carbon ions in glioblastoma cells bearing dysfunctional ATM associates with intrinsic chromosomal instability
To investigate chromosomal instability and radiation response mechanisms in glioblastoma cells.We undertook a comparative analysis of two patient-derived glioblastoma cell lines. Their resistance to low and high linear energy transfer (LET) radiation was assessed using clonogenic survival assay and their intrinsic chromosome instability status using fluorescence in situ hybridization. DNA damage was analyzed by pulsed-field gel electrophoresis and by γ-H2AX foci quantification. Expression of DNA damage response proteins was assessed by immunoblot.Increased radioresistance to X-rays as well as carbon ions was observed in glioblastoma cells exhibiting high levels of naturally occurring chromo…
A sphingosine kinase inhibitor combined with temozolomide induces glioblastoma cell death through accumulation of dihydrosphingosine and dihydroceramide, endoplasmic reticulum stress and autophagy.
AbstractGlioblastomas (GBMs) are very aggressive tumors with low chemosensitivity. The DNA-alkylating agent temozolomide (TMZ) is currently the most efficient chemotoxic drug for GBM therapy; however, many patients develop resistance to TMZ. Combining TMZ with another agent could present an improved treatment option if it could overcome TMZ resistance and avoid side effects. Sphingosine kinase inhibitors (SKIs) have emerged as anticancer agents. Sphingosine kinases are often overexpressed in tumors where their activity of phosphorylating sphingosine (Sph) contributes to tumor growth and migration. They control the levels of the pro-apoptotic ceramide (Cer) and Sph and of the pro-survival sp…
Abstract 2935: Novel combination of repurposed drugs induces complete cell invasion arrest of glioblastoma in vitro
Abstract Introduction: Glioblastoma multiforme (GBM) is an aggressive and lethal cancer with a poor prognosis even after conventional treatment (surgery, radiation, chemotherapy). Temozolomide (TMZ) is a standard cyotoxic agent used, despite resistance leading to recurrence. Therefore, additional strategies for targeting the tumor environment are needed. We demonstrate a combination of approved drugs (CAD) repurposed to target GBM leads to complete arrest of GBM cell invasion. Each drug in the combination individually targets diverse tumor pathways: 1) invasion via MMP2 (doxycycline); 2) angiogenesis, inflammation, and proliferation via p53-dependent G1 cell-cycle arrest (celecoxib); 3) aut…
Glutathione peroxidase 1 activity dictates the sensitivity of glioblastoma cells to oxidative stress.
The high intratumoral and intertumoral heterogeneity of glioblastoma (GBM) leads to resistance to different therapies, and hence, selecting an effective therapy is very challenging. We hypothesized that the antioxidant enzyme status is a significant feature of GBM heterogeneity. The most important reactive oxygen/nitrogen species (ROS/RNS) detoxification mechanisms include superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx). Expression and activity of these enzymes and the cellular response to induced oxidative stress were systematically analyzed and compared between GBM cells and nontransformed glial cells of both human and murine origin. Regardless of cell type or speci…
Assessing the reliability of gene expression measurements in very-low-numbers of human monocyte-derived macrophages
Abstract Tumor-derived primary cells are essential for in vitro and in vivo studies of tumor biology. The scarcity of this cellular material limits the feasibility of experiments or analyses and hence hinders basic and clinical research progress. We set out to determine the minimum number of cells that can be analyzed with standard laboratory equipment and that leads to reliable results, unbiased by cell number. A proof-of-principle study was conducted with primary human monocyte-derived macrophages, seeded in decreasing number and constant cell density. Gene expression of cells stimulated to acquire opposite inflammatory states was analyzed by quantitative PCR. Statistical analysis indicat…
Autophagy
Klionsky, Daniel J. et al.
Comparative analysis of the effects of a sphingosine kinase inhibitor to temozolomide and radiation treatment on glioblastoma cell lines.
ABSTRACT Glioblastoma multiforme (GBM) exhibits high resistance to the standard treatment of temozolomide (TMZ) combined with radiotherapy, due to its remarkable cell heterogeneity. Accordingly, there is a need to target alternative molecules enhancing specific GBM autocrine or paracrine mechanisms and amplifying the effect of standard treatment. Sphingosine 1-phosphate (S1P) is such a lipid target molecule with an important role in cell invasion and proliferation. Sphingosine kinase inhibitors (SKI) prevent S1P formation and induce increased production of reactive oxygen species (ROS), which may potentiate radiation cytotoxicity. We analyzed the effect of SKI singular versus combined treat…
Metabolic and inflammatory reprogramming of macrophages by ONC201 translates in a pro-inflammatory environment even in presence of glioblastoma cells
Tumor-associated macrophages facilitate tumor progression and resistance to therapy. Their capacity for metabolic and inflammatory reprogramming represents an attractive therapeutic target. ONC201/TIC10 is an anticancer molecule that antagonizes the dopamine receptor D2 and affects mitochondria integrity in tumor cells. We examined whether ONC201 induces a metabolic and pro-inflammatory switch in primary human monocyte-derived macrophages that reactivates their antitumor activities, thus enhancing the onco-toxicity of ONC201. Contrary to glioblastoma cells, macrophages exhibited a low ratio of dopamine receptors D2/D5 gene expression and were resistant to ONC201 cytotoxicity. Macrophages re…
Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition) 1
Contains fulltext : 232759.pdf (Publisher’s version ) (Closed access) In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to…
<i>MYC</i> Dosage Compensation is Mediated by miRNA-Transcription Factor Interactions in Aneuploid Cancer
Cancer complexity is consequence of genomic instability leading to aneuploidy. We hypothesize that dosage compensation of critical genes arise from systems-level properties for cancer cells to withstand the negative effects of aneuploidy. We developed a computational platform to identify a network of miRNAs and transcription factors interacting with candidate dosage-compensated genes using NCI-60 multi-omic data. We next constructed a mathematical model where the property of dosage compensation emerged for MYC and STAT3 and was dependent on the kinetic parameters of their feedback and feed-forward interactions with four miRNAs. We developed a genetic tug-of-war approach by overexpressing an…
Glioblastoma cells induce differential glutamatergic gene expressions in human tumor-associated microglia/macrophages and monocyte-derived macrophages
Glioblastoma cells produce and release high amounts of glutamate into the extracellular milieu and subsequently can trigger seizure in patients. Tumor-associated microglia/macrophages (TAMs), consisting of both parenchymal microglia and monocytes-derived macrophages (MDMs) recruited from the blood, are known to populate up to 1/3 of the glioblastoma tumor environment and exhibit an alternative, tumor-promoting and supporting phenotype. However, it is unknown how TAMs respond to the excess extracellular glutamate in the glioblastoma microenvironment. We investigated the expressions of genes related to glutamate transport and metabolism in human TAMs freshly isolated from glioblastoma resecti…
Autophagy
In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide…