Explore the vast range of titles available.

The invasive capacity of GBM is one of the key tumoral features associated with treatment resistance, recurrence, and poor overall survival. The molecular machinery underlying GBM invasiveness comprises an intricate network of signaling pathways and interactions with the extracellular matrix and host cells. Among them, PI3k/Akt, Wnt, Hedgehog, and NFkB play a crucial role in the cellular processes related to invasion. A better understanding of these pathways could potentially help in developing new therapeutic approaches with better outcomes. Nevertheless, despite significant advances made over the last decade on these molecular and cellular mechanisms, they have not been translated into the clinical practice. Moreover, targeting the infiltrative tumor and its significance regarding outcome is still a major clinical challenge. For instance, the pre- and intraoperative methods used to identify the infiltrative tumor are limited when trying to accurately define the tumor boundaries and the burden of tumor cells in the infiltrated parenchyma. Besides, the impact of treating the infiltrative tumor remains unclear. Here we aim to highlight the molecular and clinical hallmarks of invasion in GBM.

Background Toll-like receptor (TLR) family members are key players in inflammation. TLR10 has been poorly studied in chronic inflammatory disorders, and its clinical relevance in rheumatoid arthritis (RA) is as yet unknown. We aimed at identifying TLR10 variants within all coding regions of the gene in patients with RA as well as studying their functional and clinical significance. Methods TLR10 gene variants were studied by performing sequencing of 66 patients with RA and 30 control subjects. A selected variant, I473T, was then analyzed in 1654 patients and 1702 healthy control subjects. The capacity of this TLR10 variant to modify the transcriptional activity of nuclear factor kappa-light-chain-enhancer of activated B cells (NFkB) was determined by using a luciferase reporter assay and analyzing the expression of NFkB target genes by quantitative polymerase chain reaction. Differences between groups were analyzed by using the Mann-Whitney U test and the unpaired two-tailed Student’s t test. Results We detected ten missense variants in the TLR10 gene and focused on the I473T substitution based on allele frequencies and the predicted functional impact. I473T variant is not associated with susceptibility to RA, but it significantly correlates with erosive disease in patients seropositive for antibodies to citrullinated protein antigens ( p  = 0.017 in the total cohort and p  = 0.0049 in female patients) and with a lower response to infliximab treatment as measured by the change in Disease Activity Score in 28 joints ( p  = 0.012) and by the European League Against Rheumatism criteria ( p  = 0.049). Functional studies showed that TLR10 reduced activation of the NFkB inflammatory pathway in hematopoietic cells, whereas the I473T variant lacked this inhibitory capacity. Consistently, after exposure to infliximab, cells expressing the I437T variant showed higher NFkB activity than cells carrying wild-type TLR10. Conclusions A TLR10 allelic variant, I473T, has impaired NFkB inhibitory activity and is highly associated with disease severity and low response to infliximab in patients with RA.

R-loops are three-stranded nucleic acid structures that accumulate on chromatin in neurological diseases and cancers and contribute to genome instability. Using a proximity-dependent labeling system, we identified distinct classes of proteins that regulate R-loops in vivo through different mechanisms. We show that ATRX suppresses R-loops by interacting with RNAs and preventing R-loop formation. Our proteomics screen also discovered an unexpected enrichment for proteins containing zinc fingers and homeodomains. One of the most consistently enriched proteins was activity-dependent neuroprotective protein (ADNP), which is frequently mutated in ASD and causal in ADNP syndrome. We find that ADNP resolves R-loops in vitro and that it is necessary to suppress R-loops in vivo at its genomic targets. Furthermore, deletion of the ADNP homeodomain severely diminishes R-loop resolution activity in vitro, results in R-loop accumulation at ADNP targets, and compromises neuronal differentiation. Notably, patient-derived human induced pluripotent stem cells that contain an ADNP syndrome-causing mutation exhibit R-loop and CTCF accumulation at ADNP targets. Our findings point to a specific role for ADNP-mediated R-loop resolution in physiological and pathological neuronal function and, more broadly, to a role for zinc finger and homeodomain proteins in R-loop regulation, with important implications for developmental disorders and cancers. R-loops are three-stranded nucleic acid structures that contribute to genome instability and accumulate in neurological diseases. Here the authors identify R-loop proximal factors, which are enriched for zinc finger and homeodomain proteins, including activity-dependent neuroprotective protein (ADNP). ADNP plays a role in R-loop resolution and loss-of-function leads to R-loop accumulation.

Background Bone tissue homeostasis relies on the coordinated activity of the bone‐forming osteoblasts and bone‐resorbing osteoclasts. Osteomesopyknosis is considered a distinctive rare sclerosing skeletal disorder of unelucidated pathophysiology and presumably autosomal dominant transmission. However, the causal genes are unknown. Methods We present a case report encompassing clinical assessments, imaging studies, and whole‐exome sequencing analysis, complemented by functional in vitro experiments. Results This new case of osteomesopyknosis was associated with a missense ALOX5 variant predicted to induce protein misfolding and proteasomal degradation. Transfection experiments demonstrated that the variant was associated with reduced protein levels restored by proteasomal inhibition with bortezomib. Likewise, gene expression analysis showed that the mutated gene was associated with a decreased RANKL/OPG ratio, which is a critical driver of osteoclast precursor differentiation. Conclusion Our data indicate impaired bone resorption as the underlying mechanism of this rare osteosclerosis, implicating ALOX5 pathogenic variants as potential etiological factors. Osteomesopyknosis is a rare bone sclerosing disorder of unelucidated pathophysiology with a presumably autosomal dominant transmission. However, the causal genes are unknown. Here we report a new case of osteomesopyknosis associated with a missense ALOX5 variant predicted to induce protein misfolding and proteasomal degradation. Gene expression analysis showed that it was associated with a decreased RANKL/OPG ratio, which is a critical driver of osteoclast precursor differentiation.

Developing a simple, fast, and label-free method for discrimination between live cancer cells and normal cells in biological samples still remains a challenge. Here, a system is described that fulfills these features to analyze individual living cells. The system consists of a gold nanohole array biosensor plus a microscope optical design to isolate the spectral response of a single cell. It is demonstrated that differences in the spectral behavior between tumor (colorectal cancer cell lines and primary cells from colorectal cancer tissue) and non-tumor cells (peripheral blood mononuclear cells, skin fibroblasts and colon epithelial cells) are influenced by the actin cortex, which lies within the short penetration depth of the surface plasmon electromagnetic field. The efficacy of this system was assessed by the analysis of about one thousand single cells showing the highest discrimination capacity between normal colon epithelial cells and colorectal cancer cells from surgical specimens, with values of sensitivity and specificity ranging 80–100% and 87–100%, respectively. It is also demonstrated that cell discrimination capacity of the system is highly reduced by disrupting the formation of actin cortex. This plasmonic system may find wide applications in biomedicine and to study key cellular processes that involve the actin cortex, including proliferation, differentiation, and migration.

Meester–Loeys syndrome (MLS) is an X-linked connective tissue disorder caused by pathogenic BGN variants. We describe a family carrying a novel missense variant. The index male, initially diagnosed with Ehlers–Danlos syndrome, had joint hypermobility, multiple visceral artery aneurysms, and recurrent musculoskeletal problems. A brother of the proband had an aortic root aneurysm. Female carriers had no or only minor manifestations. Studies of the aortic wall were consistent with a dysregulation of the TGF-β/SMAD pathway and assays with reporter vectors revealed reduced canonical Wnt and TGF-β activity in cell lines expressing mutant biglycan. However, patients’ dermal fibroblasts did not show consistent differences in the nuclear abundance of β-catenin or p-SMAD2/3 compared to cells from controls. This 3-generation family expands the genetic and phenotypic spectrum of MLS and underscores the importance of considering BGN testing in hypermobility syndromes to enable early surveillance and targeted management.

We have previously shown that the transmembrane protein ODZ1 serves for glioblastoma (GBM) cells to invade the surrounding tissue through activation of RhoA/ROCK pathway. However, the transcriptional machinery used by GBM cells to regulate the expression of ODZ1 is unknown. Here we show that interaction with tumor microenvironment elements, mainly activated monocytes through IL-6 secretion, and the extracellular matrix protein fibronectin, induces the Stat3 transcriptional pathway and upregulates ODZ1 which results in GBM cell migration. This signaling route is abrogated by blocking the IL-6 receptor, inhibiting Jak kinases or knocking down Stat3. Furthermore, we have identified a Stat3 responsive element in the ODZ1 gene promoter, about 1 kb from the transcription start site. Luciferase-reporter assays confirmed that the promoter responds to the presence of monocytic cells and this activation is greatly reduced when the Stat3 site is mutated or following treatment with a neutralizing anti-IL-6 receptor antibody or transfecting GBM cells with a dominant negative variant of Stat3. Overall, we show that monocyte-secreted IL-6 and the extracellular matrix protein fibronectin activate the axis Stat3-ODZ1 and promote migration of GBM cells. This is the first described transcriptional mechanism used by tumor cells to promote the expression of the invasion factor ODZ1.

We have previously described that the NFκB pathway is upregulated during differentiation of glioblastoma stem-like cells (GSCs) which keeps differentiating GSCs in a proliferative astrocytic precursor state. However, extracellular signals and cellular mediators of this pathway are not clear yet. Here, we show that TLR4 is a key factor to promote NFκB activation in differentiating GSCs. TLR4 is upregulated during differentiation of GSCs and promotes transcriptional activation of NFκB as determined by luciferase-reporter assays and expression of NFκB target genes. Downregulation of TLR4 by shRNAs or blockade with anti-TLR4 specific antibodies drastically inhibited NFκB activity which promoted further differentiation and reduced proliferation of GSCs. We found that hyaluronic acid (HA), a main component of brain extracellular matrix, triggers the TLR4-NFκB pathway in differentiating GSCs. Moreover, HA is synthesized and released by GSCs undergoing differentiation and leads to transcriptional activation of NFκB, which is inhibited following downregulation of TLR4 or blockade of HA synthesis. Thus, we have demonstrated that during the process of differentiation, GSCs upregulate TLR4 and release the TLR4 ligand HA, which activates the TLR4-NFκB signaling pathway. This strategy may efficiently be used by differentiating GSCs to maintain their proliferative potential and consequently their tumorigenic capacity.

Glioblastoma multiforme (GBM)-initiating cells (GICs) represent a tumor subpopulation with neural stem cell-like properties that is responsible for the development, progression and therapeutic resistance of human GBM. We have recently shown that blockade of NFκB pathway promotes terminal differentiation and senescence of GICs both in vitro and in vivo, indicating that induction of differentiation may be a potential therapeutic strategy for GBM. MicroRNAs have been implicated in the pathogenesis of GBM, but a high-throughput analysis of their role in GIC differentiation has not been reported. We have established human GIC cell lines that can be efficiently differentiated into cells expressing astrocytic and neuronal lineage markers. Using this in vitro system, a microarray-based high-throughput analysis to determine global expression changes of microRNAs during differentiation of GICs was performed. A number of changes in the levels of microRNAs were detected in differentiating GICs, including over-expression of hsa-miR-21, hsa-miR-29a, hsa-miR-29b, hsa-miR-221 and hsa-miR-222, and down-regulation of hsa-miR-93 and hsa-miR-106a. Functional studies showed that miR-21 over-expression in GICs induced comparable cell differentiation features and targeted SPRY1 mRNA, which encodes for a negative regulator of neural stem-cell differentiation. In addition, miR-221 and miR-222 inhibition in differentiated cells restored the expression of stem cell markers while reducing differentiation markers. Finally, miR-29a and miR-29b targeted MCL1 mRNA in GICs and increased apoptosis. Our study uncovers the microRNA dynamic expression changes occurring during differentiation of GICs, and identifies miR-21 and miR-221/222 as key regulators of this process.

We have previously shown that the transmembrane protein ODZ1 promotes cytoskeletal remodeling of glioblastoma (GBM) cells and invasion of the surrounding parenchyma through the activation of a RhoA–ROCK pathway. We also described that GBM cells can control the expression of ODZ1 through transcriptional mechanisms triggered by the binding of IL-6 to its receptor and a hypoxic environment. Epidermal growth factor (EGF) plays a key role in the invasive capacity of GBM. However, the molecular mechanisms that enable tumor cells to acquire the morphological changes to migrate out from the tumor core have not been fully characterized. Here, we show that EGF is able to induce the expression of ODZ1 in primary GBM cells. We analyzed the levels of the EGF receptor (EGFR) in 20 GBM primary cell lines and found expression in 19 of them by flow cytometry. We selected two cell lines that do or do not express the EGFR and found that EGFR-expressing cells responded to the EGF ligand by increasing ODZ1 at the mRNA and protein levels. Moreover, blockade of EGF-EGFR binding by Cetuximab, inhibition of the p38 MAPK pathway, or Additionally, the siRNA-mediated knockdown of MAPK11 (p38β MAPK) reduced the induction of ODZ1 in response to EGF. Overall, we show that EGF may activate an EGFR-mediated signaling pathway through p38β MAPK, to upregulate the invasion factor ODZ1, which may initiate morphological changes for tumor cells to invade the surrounding parenchyma. These data identify a new candidate of the EGF–EGFR pathway for novel therapeutic approaches.