Stem cell quiescence acts as a tumour suppressor in squamous tumours
Menée sur des modèles murins et des échantillons tumoraux prélevés sur des patients atteints d'un carcinome épidermoïde, cette étude met en évidence des mécanismes par lesquels, en entretenant un état de quiescence, la protéine Pten joue un rôle de suppresseur de tumeurs dans les cellules souches des follicules pileux
In some organs, adult stem cells are uniquely poised to serve as cancer cells of origin. It is unclear, however, whether tumorigenesis is influenced by the activation state of the adult stem cell. Hair follicle stem cells (HFSCs) act as cancer cells of origin for cutaneous squamous cell carcinoma and undergo defined cycles of quiescence and activation. The data presented here show that HFSCs are unable to initiate tumours during the quiescent phase of the hair cycle, indicating that the mechanisms that keep HFSCs dormant are dominant over the gain of oncogenes (such as Ras) or the loss of tumour suppressors (such as p53). Furthermore, Pten activity is necessary for quiescence-based tumour suppression, as its deletion alleviates tumour suppression without affecting proliferation. These data demonstrate that stem cell quiescence is a form of tumour suppression in HFSCs, and that Pten plays a role in maintaining quiescence in the presence of tumorigenic stimuli.