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Biology subjects

Van Seuningen, I.

Publications and source records attributed to Van Seuningen, I..

4 recordsLinked to original sources

A crypt-operating DNA repair checkpoint for uncoupling regeneration and tumorigenesis

The rapid turnover of the intestinal epithelium increases its vulnerability to genomic instability and environmental insults such as irradiation. Defects in DNA damage resolution can compromise epithelial regeneration, promote chronic tissue injury, and predispose to colorectal tumorigenesis. However, the intrinsic mechanisms that coordinate DNA repair with epithelial regeneration at the crypt level remain poorly defined. Here, we identify the Nod-like receptor protein 6 (Nlrp6) as a key epithelial regulator of genome surveillance and regenerative control in intestinal crypts. Nlrp6 is strategically expressed in crypt base columnar cells, where it preserves crypt homeostasis by restraining proliferation under genotoxic stress conditions. Loss of Nlrp6 in crypt base columnar cells results in uncontrolled oncogenic stress, defective epithelial regeneration, and accumulation of unrepaired DNA damage, features associated with poor prognosis in colorectal cancer. Conversely, aberrant Nlrp6 overexpression induces cytoplasmic retention of Csnk2 catalytic subunits, limiting their nuclear availability when DNA repair is required. These findings position Nlrp6 as a non-canonical, cell-intrinsic surveillance mechanism that links DNA damage responses to epithelial regeneration through Csnk2-dependent signaling. Collectively, our study reveals a crypt-intrinsic DNA repair pathway that governs epithelial regeneration and disease outcomes, providing new insight into how genome instability and regenerative failure contribute to colorectal cancer progression.

cell biology↗

Long non-coding RNA UCA1 affects chromatin remodeling via SMARCA2-containing SWI/SNF complex in human colorectal cancer.

Differential lncRNA expression has been correlated to clinical characteristics of colorectal cancers (CRC), which are the second leading cause of cancer-related deaths. LncRNA UCA1 plays a role in epigenetic gene regulation in diverse cancers. We studied CRC cell properties in CRISPR/Cas9 HT29-derived models and, interestingly, UCA1-depleted HT29 cells presented an increased stem-cell phenotype. We show that loss of UCA1 affected SWI/SNF chromatin remodeling complexes, which are previously shown to be involved in maintaining stem-cell properties. Not only was UCA1 permissive for induced SWI/SNF subunit SMARCA2 (BRM) expression upon chemo-drug treatment, but it also affected subunit compositions of SWI/SNF complexes by direct interaction of UCA1 with both ATP helicase BRM and BRG1. UCA1 is known to stimulate proliferation and decrease apoptosis, and we here show that it can restrain cells from a stem cell phenotype. The dual action of UCA1 revealed in this study highlights the complex actions of lncRNAs in cancer.

cancer biology↗

A coregulatory influence map of glioblastoma heterogeneity and plasticity - From cells in vitro to tumors and back again

We present GBM-cRegMap, an online resource providing a comprehensive coregulatory influence network perspective on glioblastoma (GBM) heterogeneity and plasticity. Using representation learning algorithms, we derived two components of this resource: GBM-CoRegNet, a highly specific coregulatory network of tumor cells, and GBM-CoRegMap, a unified network influence map based on 1612 tumors from 16 studies. As a widely applicable closed-loop system connecting cellular models and tumors, GBM-cRegMap will provide the GBM research community with an easy-to-use web tool (https://gbm.cregmap.com) that maps any existing or newly generated transcriptomic "query" data to a reference coregulatory network and a large-scale manifold of disease heterogeneity. Using GBM-cRegMap, we demonstrated the synergy between the two components by refining the molecular classification of GBM, identifying potential key regulators, and aligning the transcriptional profiles of tumors and in vitro models. Through the amalgamation of a vast dataset, we validated the proneural (PN)-mesenchymal (MES) axis and identified three subclasses of classical (CL) tumors: astrocyte-like (CL-A), epithelial basal-like (CL-B), and cilium-rich (CL-C). We revealed the CL-C subclass, an intermediate state demonstrating the plasticity of GBM cells along the PN-MES axis under chemotherapy. We identified key regulators, such as PAX8, and NKX2.5, involved in TMZ resistance. Notably, NKX2.5, more expressed in higher-grade gliomas, negatively impacts patient survival and regulates genes involved in glucose metabolism. O_FIG O_LINKSMALLFIG WIDTH=152 HEIGHT=200 SRC="FIGDIR/small/609303v1_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@c7a401org.highwire.dtl.DTLVardef@e0681corg.highwire.dtl.DTLVardef@d31f55org.highwire.dtl.DTLVardef@ae350f_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

TGF-βRII knock-down promotes tumor growth and chemoresistance to gemcitabine of pancreatic cancer cells via phosphorylation of STAT3

Pancreatic adenocarcinoma (PDAC) is one of the most deadly cancers in the western countries because of a lack of early diagnostic markers and efficient therapeutics. At the time of diagnosis, more than 80% of patients have metastasis or locally advanced cancer and are therefore not eligible for surgical resection. Pancreatic cancer cell also harbour a high resistance to chemotherapeutic drugs such as gemcitabine that is one of the main palliative treatment for PDAC.\n\nTGF-{beta} possesses both tumor-suppressive and oncogenic activities in pancreatic cancer. TGF-{beta} signalling pathway plays complex role during carcinogenesis by initially inhibiting epithelial growth and later promoting the progression of advanced tumors and thus emerged as tumor suppressor pathway. TGF-{beta} binds to its receptor TGF-{beta}RII and activates different pathways: canonical pathway involving the Smad proteins and alternative pathways such as MAPKs. Smad4 is mutated in 50-80% of PDAC. Mutations of TGF-{beta}RII also occurs (5-10%). In order to decipher the role of TGF-{beta} in carcinogenesis and chemoresistance, we decided to characterize the knocking down of TGF-{beta}RII that is the first actor of TGF-{beta} signalling. We developed pancreatic cancer cell lines stably invalidated for TGF-{beta}RII and studied the impact on biological properties of pancreatic cancer cells both in vitro and in vivo. We show that TGF-{beta}RII silencing alters tumor growth and migration as well as resistance to. TGF-{beta}RII silencing also leads to S727 STAT3 and S-63 c-Jun phosphorylation, decrease of MRP3 and increase of MRP4 ABC transporter expression and induction of a partial EMT phenotype.\n\nIn the future, the better understanding TGF-{beta} signaling pathways and underlying cellular mechanisms in chemoresistance to gemcitabine may bring new therapeutic tools to clinicians.

cancer biology↗