Functions of LKB1 in neural crest development: The story unfolds.

Neural crest cells (NCCs) are highly motile, multipotent, embryonic cells that delaminate from the dorsal edges of the neural tube. NCCs follow stereotypical long-range migratory pathways to reach target organs during development, where they give rise to multiple derivatives. The identification of reservoirs of neural crest stem cells that persist to adulthood has recently aroused renewed interest in the biology of NCCs. In this context, several recent studies have demonstrated the essential role of the metabolic kinase LKB1 in NCC establishment. This review surveys how LKB1 governs the formation and maintenance of several neural crest derivatives, including facial bones, melanocytes, Schwann cells, and the enteric nervous system. We also detail the underlying molecular mechanisms that involve downstream effectors of LKB1, in particular the contribution of the AMPK-mTOR signaling pathway to both polarity and metabolic processes. Collectively, these recent discoveries open promising perspectives for new therapeutic applications for the treatment of neural crest disorders.

P2x4 receptor promotes mammary cancer progression by sustaining autophagy and associated mesenchymal transition.

Metastatic progression is a major burden for breast cancer patients and is associated with the ability of cancer cells to overcome stressful conditions, such as nutrients deprivation and hypoxia, and to gain invasive properties. Autophagy and epithelial-to-mesenchymal transition are critical contributors to these processes. Here, we show that the P2X4 purinergic receptor is upregulated in breast cancer biopsies from patients and it is primarily localised in endolysosomes. We demonstrate that P2X4 enhanced invasion in vitro, as well as mammary tumour growth and metastasis in vivo. The pro-malignant role of P2X4 was mediated by the regulation of lysosome acidity, the promotion of autophagy and cell survival. Furthermore, the autophagic activity was associated with epithelial-to-mesenchymal transition (EMT), and this role of P2X4 was even more pronounced under metabolic challenges. Pharmacological and gene silencing of P2X4 inhibited both autophagy and EMT, whereas its rescue in knocked-down cells led to the restoration of the aggressive phenotype. Together, our results demonstrate a previously unappreciated role for P2X4 in regulating lysosomal functions and fate, promoting breast cancer progression and aggressiveness.