The Sox9 transcription factor determines glial fate choice in the developing spinal cord
GENES & DEVELOPMENT
Authors: Stolt, CC; Lommes, P; Sock, E; Chaboissier, MC; Schedl, A; Wegner, M
Abstract
The mechanism that causes neural stem cells in the central nervous system to switch from neurogenesis to gliogenesis is poorly understood. Here we analyzed spinal cord development of mice in which the transcription factor Sox9 was specifically ablated from neural stem cells by the CRE/loxP recombination system. These mice exhibit defects in the specification of oligodendrocytes and astrocytes, the two main types of glial cells in the central nervous system. Accompanying an early dramatic reduction in progenitors of the myelin-forming oligodendrocytes, there was a transient increase in motoneurons. Oligodendrocyte progenitor numbers recovered at later stages of development, probably owing to compensatory actions of the related Sox10 and Sox8, both of which overlap with Sox9 in the oligodendrocyte lineage. In agreement, compound loss of Sox9 and Sox10 led to a further decrease in oligodendrocyte progenitors. Astrocyte numbers were also severely reduced in the absence of Sox9 and did not recover at later stages of spinal cord development. Taking the common origin of motoneurons and oligodendrocytes as well as V2 interneurons and some astrocytes into account, stem cells apparently fail to switch from neurogenesis to gliogenesis in at least two domains of the ventricular zone, indicating that Sox9 is a major molecular component of the neuron-glia switch in the developing spinal cord.
Aurora-A/SOX8/FOXK1 signaling axis promotes chemoresistance via suppression of cell senescence and induction of glucose metabolism in ovarian cancer organoids and cells
THERANOSTICS
Authors: Sun, Huizhen; Wang, Husheng; Wang, Xue; Aoki, Yoichi; Wang, Xinjing; Yang, Yufei; Cheng, Xi; Wang, Ziliang; Wang, Xipeng
Abstract
Rationale: Cisplatin derivatives are first-line chemotherapeutic agents for epithelial ovarian cancer. However, chemoresistance remains a major hurdle for successful therapy and the underlying molecular mechanisms are poorly understood at present. Methods: RNA sequencing of organoids (PDO) established from cisplatin-sensitive and -resistant ovarian cancer tissue samples was performed. Glucose metabolism, cell senescence, and chemosensitivity properties were subsequently examined. Immunoprecipitation, mass spectrometry, Forster resonance energy transfer-fluorescence lifetime imaging (FRET-FLIM), luciferase reporter assay, ChIP and animal experiments were conducted to gain insights into the specific functions and mechanisms of action of the serine/threonine kinase, Aurora-A, in ovarian cancer. Results: Aurora-A levels were significantly enhanced in cisplatin-resistant PDO. Furthermore, Aurora-A promoted chemoresistance through suppression of cell senescence and induction of glucose metabolism in ovarian cancer organoids and cells. Mechanistically, Aurora-A bound directly to the transcription factor sex determining region Y-box 8 (SOX8) and phosphorylated the Ser327 site, in turn, regulating genes related to cell senescence and glycolysis, including hTERT, P16, LDHA and HK2, through enhancement of forkhead-box kl (FOXK1) expression. Conclusions: Aurora-A regulates cell senescence and glucose metabolism to induce cisplatin resistance by participating in the SOX8/FOXK1 signaling axis in ovarian cancer. Our collective findings highlight a novel mechanism of cisplatin resistance and present potential therapeutic targets to overcome chemoresistance in ovarian cancer.