ERBB2 Comprehensive Profiling and Prognostication in Stage III Colon Cancer: Findings From PETACC8 and IDEA-France Cohorts.

Background & Aims: ERBB2 pathway activation, through amplification or activating mutations, represents a new target for colon cancer (CC) treatment. Molecular methods were compared with the gold standard for assessing ERBB2 status, and the prognostic value of ERBB2 amplification, mutations, and expression was determined using data from 2 phase 3 trials involving nearly 3000 patients with stage III CC.

Methods: In the PETACC8 trial, immunohistochemistry and fluorescence in situ hybridization, DNA, and RNA analysis were performed on 1813, 1719, and 1733 samples, respectively.

PrP controls epithelial-to-mesenchymal transition in EGFR-mutated NSCLC: implications for TKI resistance and patient follow-up.

Patients with EGFR-mutated non-small cell lung cancer (NSCLC) benefit from treatment with tyrosine kinase inhibitors (TKI) targeting EGFR. Despite improvements in patient care, especially with the 3rd generation TKI osimertinib, disease relapse is observed in all patients. Among the various processes involved in TKI resistance, epithelial-to-mesenchymal transition (EMT) is far from being fully characterized.

Wnt, glucocorticoid and cellular prion protein cooperate to drive a mesenchymal phenotype with poor prognosis in colon cancer.

Background: The mesenchymal subtype of colorectal cancer (CRC), associated with poor prognosis, is characterized by abundant expression of the cellular prion protein PrP, which represents a candidate therapeutic target. How PrP is induced in CRC remains elusive. This study aims to elucidate the signaling pathways governing PrP expression and to shed light on the gene regulatory networks linked to PrP.

Clinical Challenges of Consensus Molecular Subtype CMS4 Colon Cancer in the Era of Precision Medicine.

Over the past decade, our understanding of the diversity of colorectal cancer has expanded significantly, raising hopes of tailoring treatments more precisely for individual patients. A key achievement in this direction was the establishment of the consensus molecular classification, particularly identifying the challenging consensus molecular subtype (CMS) CMS4 associated with poor prognosis. Because of its aggressive nature, extensive research is dedicated to the CMS4 subgroup.

DLK1/DIO3 locus upregulation by a β-catenin-dependent enhancer drives cell proliferation and liver tumorigenesis.

The CTNNB1 gene, encoding β-catenin, is frequently mutated in hepatocellular carcinoma (HCC, ∼30%) and in hepatoblastoma (HB, >80%), in which DLK1/DIO3 locus induction is correlated with CTNNB1 mutations. Here, we aim to decipher how sustained β-catenin activation regulates DLK1/DIO3 locus expression and the role this locus plays in HB and HCC development in mouse models deleted for Apc (Apc) or Ctnnb1-exon 3 (β-catenin) and in human CTNNB1-mutated hepatic cancer cells. We identified an enhancer site bound by TCF-4/β-catenin complexes in an open conformation upon sustained β-catenin activation (DLK1-Wnt responsive element [WRE]) and increasing DLK1/DIO3 locus transcription in β-catenin-mutated human HB and mouse models.

Downregulation of mitochondrial complex I induces ROS production in colorectal cancer subtypes that differently controls migration.

Background: Colorectal cancer (CRC) can be classified into four molecular subtypes (CMS) among which CMS1 is associated with the best prognosis, while CMS4, the mesenchymal subtype, has the worst outcome. Although mitochondria are considered to be hubs of numerous signaling pathways, the study of mitochondrial metabolism has been neglected for many years. Mitochondrial Complex I (CI) plays a dual role, both in energy and reactive oxygen species (ROS) production.

Transcriptomic Signatures of MSI-High Metastatic Colorectal Cancer Predict Efficacy of Immune Checkpoint Inhibitors.

Purpose: Microsatellite instability (MSI) is currently the only predictive biomarker of efficacy of immune checkpoint inhibitors (ICI) in metastatic colorectal cancers (mCRC). However, 10% to 40% of patients with MSI mCRC will experience a primary resistance to ICI.

Experimental Design: In two cohorts of patients with MSI mCRC treated with ICI (exploratory, N = 103; validation, N = 35), 3' RNA sequencing was performed from primary tumors.

New hormone receptor-positive breast cancer mouse cell line mimicking the immune microenvironment of anti-PD-1 resistant mammary carcinoma.

Background: Progress in breast cancer (BC) research relies on the availability of suitable cell lines that can be implanted in immunocompetent laboratory mice. The best studied mouse strain, C57BL/6, is also the only one for which multiple genetic variants are available to facilitate the exploration of the cancer-immunity dialog. Driven by the fact that no hormone receptor-positive (HR) C57BL/6-derived mammary carcinoma cell lines are available, we decided to establish such cell lines.

Intratumor heterogeneity and cell secretome promote chemotherapy resistance and progression of colorectal cancer.

The major underlying cause for the high mortality rate in colorectal cancer (CRC) relies on its drug resistance, to which intratumor heterogeneity (ITH) contributes substantially. CRC tumors have been reported to comprise heterogeneous populations of cancer cells that can be grouped into 4 consensus molecular subtypes (CMS). However, the impact of inter-cellular interaction between these cellular states on the emergence of drug resistance and CRC progression remains elusive.

A proof of concept for targeting the PrP - Amyloid β peptide interaction in basal prostate cancer and mesenchymal colon cancer.

The cellular prion protein PrP partners with caveolin-1 (CAV1) in neurodegenerative diseases but whether this interplay occurs in cancer has never been investigated. By leveraging patient and cell line datasets, we uncover a molecular link between PrP and CAV1 across cancer. Using cell-based assays, we show that PrP regulates the expression of and interacts with CAV1.

The Cellular Prion Protein and the Hallmarks of Cancer.

Beyond its causal involvement in a group of neurodegenerative diseases known as Transmissible Spongiform Encephalopathies, the cellular prion protein PrP is now taking centre stage as an important contributor to cancer progression in various types of solid tumours. The prion cancer research field has progressively expanded in the last few years and has yielded consistent evidence for an involvement of PrP in cancer cell proliferation, migration and invasion, therapeutic resistance and cancer stem cell properties. Most recent data have uncovered new facets of the biology of PrP in cancer, ranging from its control on enzymes involved in immune tolerance to its radio-protective activity, by way of promoting angiogenesis.

Prognostic value of the PrP-ILK-IDO1 axis in the mesenchymal colorectal cancer subtype.

The CMS4 mesenchymal subtype of colorectal cancer (CRC) is associated with poor prognosis and resistance to treatment. The cellular prion protein PrP is overexpressed in CMS4 tumors and controls the expression of a panel of CMS4-specific genes in CRC cell lines. Here, we sought to investigate PrP downstream pathways that may underlie its role in CMS4 CRC.

Intratumor CMS Heterogeneity Impacts Patient Prognosis in Localized Colon Cancer.

Purpose: The consensus molecular subtypes (CMS) represent a significant advance in the understanding of intertumor heterogeneity in colon cancer. Intratumor heterogeneity (ITH) is the new frontier for refining prognostication and understanding treatment resistance. This study aims at deciphering the transcriptomic ITH of colon cancer and understanding its potential prognostic implications.

Co-invalidation of Prnp and Sprn in FVB/N mice affects reproductive performances and highlight complex biological relationship between PrP and Shadoo.

Shadoo and PrP belongs to the same protein family, whose biological function remains poorly understood. Previous experiments reported potential functional redundancies or antagonisms between these two proteins, depending on the tissue analysed. While knockdown experiments suggested the requirement of Shadoo in the absence of PrP during early mouse embryogenesis, knockout ones, on the contrary, highlighted little impact, if any, of the double-knockout of these two loci.

YAP/TAZ Signalling in Colorectal Cancer: Lessons from Consensus Molecular Subtypes.

Recent advance in the characterization of the heterogeneity of colorectal cancer has led to the definition of a consensus molecular classification within four CMS subgroups, each associated with specific molecular and clinical features. Investigating the signalling pathways that drive colorectal cancer progression in relation to the CMS classification may help design therapeutic strategies tailored for each CMS subtype. The two main effectors of the Hippo pathway YAP and its paralogue TAZ have been intensively scrutinized for their contribution to colon carcinogenesis.

Cellular prion protein dysfunction in a prototypical inherited metabolic myopathy.

Inherited fatty acid oxidation diseases in their mild forms often present as metabolic myopathies. Carnitine Palmitoyl Transferase 2 (CPT2) deficiency, one such prototypical disorder is associated with compromised myotube differentiation. Here, we show that CPT2-deficient myotubes exhibit defects in focal adhesions and redox balance, exemplified by increased SOD2 expression.

The cellular prion protein beyond prion diseases.

The cellular prion protein (PrPC), a cell surface glycoprotein originally identified for its central role in prion diseases (also called transmissible spongiform encephalopathies), has recently been implicated in the pathogenesis of other neurodegenerative disorders, such as Alzheimer’s and Parkinson’s diseases, by acting as a toxicity-transducing receptor for different misfolded protein isoforms, or in some case by exerting neuroprotective effects. Interestingly, PrPC has also been reported to play unexpected functions outside the nervous system, for example by contributing to myelin homeostasis, regulating specific processes of the immune system and participating in various aspects of cancer progression. Collectively, these observations point to a much broader role for PrPC in physiological and disease processes than originally assumed.

The cellular prion protein is a stress protein secreted by renal tubular cells and a urinary marker of kidney injury.

Endoplasmic Reticulum (ER) stress underlies the pathogenesis of numerous kidney diseases. A better care of patients with kidney disease involves the identification and validation of ER stress biomarkers in the early stages of kidney disease. For the first time to our knowledge, we demonstrate that the prion protein PrP is secreted in a conventional manner by ER-stressed renal epithelial cell under the control of the transcription factor x-box binding protein 1 (XBP1) and can serve as a sensitive urinary biomarker for detecting tubular ER stress.

The cellular prion protein controls the mesenchymal-like molecular subtype and predicts disease outcome in colorectal cancer.

Background: Comprehensive transcriptomic analyses have shown that colorectal cancer (CRC) is heterogeneous and have led to the definition of molecular subtypes among which the stem-cell, mesenchymal-like group is associated with poor prognosis. The molecular pathways orchestrating the emergence of this subtype are incompletely understood. In line with the contribution of the cellular prion protein PrP to stemness, we hypothesize that deregulation of this protein could lead to a stem-cell, mesenchymal-like phenotype in CRC.

A new AMPK activator, GSK773, corrects fatty acid oxidation and differentiation defect in CPT2-deficient myotubes.

Carnitine palmitoyl transferase 2 (CPT2) deficiency is one of the most common inherited fatty acid oxidation (FAO) defects and represents a prototypical mitochondrial metabolic myopathy. Recent studies have suggested a pivotal role of adenosine monophosphate-activated protein kinase (AMPK) in skeletal muscle plasticity and mitochondrial homeostasis. Thus, we tested the potential of GSK773, a novel direct AMPK activator, to improve or correct FAO capacities in muscle cells from patients harboring various mutations.

Epigenetic Control of the Notch and Eph Signaling Pathways by the Prion Protein: Implications for Prion Diseases.

Among the ever-growing number of self-replicating proteins involved in neurodegenerative diseases, the prion protein PrP remains the most infamous for its central role in transmissible spongiform encephalopathies (TSEs). In these diseases, pathogenic prions propagate through a seeding mechanism, where normal PrP molecules are converted into abnormally folded scrapie isoforms termed PrP. Since its discovery over 30 years ago, much advance has contributed to define the host-encoded cellular prion protein PrP as a critical relay of prion-induced neuronal cell demise.