Notch activation shifts the fate decision of senescent progenitors toward myofibrogenesis in human adipose tissue.

Senescence is a key event in the impairment of adipose tissue (AT) function with obesity and aging but the underlying molecular and cellular players remain to be fully defined, particularly with respect to the human AT progenitors. We have found distinct profiles of senescent progenitors based on AT location between stroma from visceral versus subcutaneous AT. In addition to flow cytometry, we characterized the location differences with transcriptomic and proteomic approaches, uncovering the genes and developmental pathways that are underlying replicative senescence. We identified key components to include INBHA as well as SFRP4 and GREM1, antagonists for the WNT and BMP pathways, in the senescence-associated secretory phenotype and NOTCH3 in the senescence-associated intrinsic phenotype. Notch activation in AT progenitors inhibits adipogenesis and promotes myofibrogenesis independently of TGFß. In addition, we demonstrate that NOTCH3 is enriched in the premyofibroblast progenitor subset, which preferentially accumulates in the visceral AT of patients with an early obesity trajectory. Herein, we reveal that NOTCH3 plays a role in the balance of progenitor fate determination preferring myofibrogenesis at the expense of adipogenesis. Progenitor NOTCH3 may constitute a tool to monitor replicative senescence and to limit AT dysfunction in obesity and aging.

GNS561, a new lysosomotropic small molecule, for the treatment of intrahepatic cholangiocarcinoma.

Among the acquired modifications in cancer cells, changes in lysosomal phenotype and functions are well described, making lysosomes a potential target for novel therapies. Some weak base lipophilic drugs have a particular affinity towards lysosomes, taking benefits from lysosomal trapping to exert anticancer activity. Here, we have developed a new lysosomotropic small molecule, GNS561, and assessed its activity in multiple in vitro intrahepatic cholangiocarcinoma models (HuCCT1 and RBE cell lines and patient-derived cells) and in a chicken chorioallantoic membrane xenograft model. GNS561 significantly reduced cell viability in two intrahepatic cholangiocarcinoma cell lines (IC50 of 1.5 ± 0.2 µM in HuCCT1 and IC50 of 1.7 ± 0.1 µM in RBE cells) and induced apoptosis as measured by caspases activation. We confirmed that GNS561-mediated cell death was related to its lysosomotropic properties. GNS561 induced lysosomal dysregulation as proven by inhibition of late-stage autophagy and induction of a dose-dependent build-up of enlarged lysosomes. In patient-derived cells, GNS561 was more potent than cisplatin and gemcitabine in 2/5 and 1/5 of the patient-derived cells models, respectively. Moreover, in these models, GNS561 was potent in models with low sensitivity to gemcitabine. GNS561 was also efficient in vivo against a human intrahepatic cholangiocarcinoma cell line in a chicken chorioallantoic membrane xenograft model, with a good tolerance at doses high enough to induce an antitumor effect in this model. In summary, GNS561 is a new lysosomotropic agent, with an anticancer activity against intrahepatic cholangiocarcinoma. Further investigations are currently ongoing to fully elucidate its mechanism of action.