Circulating tumor cells (CTCs) provide easy, repeatable, and representative access to information regarding solid tumors. However, their detection remains difficult because of their paucity, their short half-life, and the lack of reliable surface biomarkers. Flow cytometry (FC) is a fast, sensitive, and affordable technique, ideal for rare-cell detection. Adapted to CTC detection (i.e., extremely rare cells), most FC-based techniques require a time-consuming pre-enrichment step, followed by a 2-hour staining procedure, impeding the efficiency of CTC detection. We overcame these caveats and reduced the procedure to less than 1 hour, with minimal manipulation. First, cells were simultaneously fixed, permeabilized, and then stained. Second, using low-speed FC acquisition conditions and 2 discriminators (cell size and pan-cytokeratin expression), we suppressed the pre-enrichment step. Applied to blood from donors with or without known malignant diseases, this protocol ensures a high recovery of the cells of interest independently of their epithelial-mesenchymal plasticity and can predict which samples are derived from cancer donors. This proof-of-concept study lays the bases of a sensitive tool to detect CTCs from a small amount of blood upstream of in-depth analyses.

Cancer treatments are constantly evolving with new approaches to improve patient outcomes. Despite progresses, too many patients remain refractory to treatment due to either the development of resistance to therapeutic drugs and/or metastasis occurrence. Growing evidence suggests that these two barriers are due to transient survival mechanisms that are similar to those observed during stress response. We review the literature and current available open databases to study the potential role of stress response and, most particularly, the involvement of Stress Granules (proteins) in cancer. We propose that Stress Granule proteins may have prognostic value for patients.

Skeletal dysplasias are a clinically and genetically heterogeneous group of bone and cartilage disorders. A total of 436 skeletal dysplasias are listed in the 2015 revised version of the nosology and classification of genetic skeletal disorders, of which nearly 20% are still genetically and molecularly uncharacterized. We report the clinical and molecular characterization of a lethal skeletal dysplasia of the short-rib group caused by mutation of the mouse Fop gene. Fop encodes a centrosomal and centriolar satellite (CS) protein. We show that Fop mutation perturbs ciliogenesis in vivo and that this leads to the alteration of the Hedgehog signaling pathway. Fop mutation reduces CSs movements and affects pericentriolar material composition, which probably participates to the ciliogenesis defect. This study highlights the role of a centrosome and CSs protein producing phenotypes in mice that recapitulate a short rib-polydactyly syndrome when mutated.

Circulating tumor cells have a strong potential as a quasi-non-invasive tool for setting up a precision medicine strategy for cancer patients. Using a second-generation “filtration-based” technology to isolate CTCs, the Screencell™ technology (Sarcelles, France), we performed a large and simultaneous analysis of all atypical circulating tumor cells (aCTCs) isolated from the blood of metastatic breast cancer (mBC) patients. We correlated their presence with clinicopathological and survival data. We included 91 mBC patients from the PERMED-01 study. The median number of aCTCs was 8.3 per mL of blood. Three subsets of aCTCs, absent from controls, were observed in patients: single (s-aCTCs), circulating tumor micro-emboli (CTM), and giant-aCTCs (g-aCTCs). The presence of g-aCTCs was associated with shorter progression free survival and overall survival. This study highlights the heterogeneity of aCTCs in mBC patients both at the cytomorphological and molecular levels. In addition, it suggests the usefulness of the g-aCTC subset as a prognostic factor and a potential stratification tool to treat late-stage mBC patients and improve their chances of benefiting from early clinical trials.

Circulating tumor cells (CTCs) are the potential seeds of distant metastases; however, little is known about how they survive in the bloodstream. Using a large cohort of colorectal cancer (CRC) patients, we found that the pseudokinase receptor PTK7 is highly expressed in primary tumors and metastatic lesions. Consistent with previous reports, high PTK7 expression is associated with reduced disease-free survival and increased metastatic dissemination. Surprisingly, PTK7 is absent from most CTCs and undergoes a cell-autonomous ONtumor/OFFCTC/ONmetastasis switch that can be recapitulated in a xenografted mouse model, in in vitro systems, and a fluidic platform. PTK7-negative cancer cells exhibit increased expression of YAP1-driven genes, senescence-like features, and enhanced resistance to hemodynamic stress following loss of cell-cell and cell-matrix adhesion. This adaptive phenotype depends on metalloproteases, notably ADAM17, whose cleavage activity remodels the CTCs surfaceome. Functionally, the PTK7 OFFCTC state confers enhanced metastatic potential in vivo, and can be pharmacologically suppressed using metalloprotease inhibitors. Collectively, our findings identify a reversible, cell-autonomous, protease-driven surfaceome remodeling program that enables metastatic adaptation during hematogenous dissemination.