Aurora kinases are serine/threonine kinases essential for the onset and progression of mitosis. Aurora members share a similar protein structure and kinase activity, but exhibit distinct cellular and subcellular localization. AurA favors the G2/M transition by promoting centrosome maturation and mitotic spindle assembly. AurB and AurC are chromosome-passenger complex proteins, crucial for chromosome binding to kinetochores and segregation of chromosomes. Cellular distribution of AurB is ubiquitous, while AurC expression is mainly restricted to meiotically-active germ cells. In human tumors, all Aurora kinase members play oncogenic roles related to their mitotic activity and promote cancer cell survival and proliferation. Furthermore, AurA plays tumor-promoting roles unrelated to mitosis, including tumor stemness, epithelial-to-mesenchymal transition and invasion. In this review, we aim to understand the functional interplay of Aurora kinases in various types of human cells, including tumor cells. The understanding of the functional diversity of Aurora kinases could help to evaluate their relevance as potential therapeutic targets in cancer.

). † These authors contributed equally to the present work. AbstractBackground. Patients with glioblastoma (GBM) have an overall median survival of 15 months despite multimodal therapy. These catastrophic survival rates are to be correlated to systematic relapses that might arise from remaining glioblastoma stem cells (GSCs) left behind after surgery. In this line, it has recently been demonstrated that GSCs are able to escape the tumor mass and preferentially colonize the adult subventricular zone (SVZ). At a distance from the initial tumor site, these GSCs might therefore represent a high-quality model of clinical resilience to therapy and cancer relapses as they specifically retain tumor-initiating abilities. Method. While relying on recent findings that have validated the existence of GSCs in the human SVZ, we questioned the role of the SVZ niche as a potential GSC reservoir involved in therapeutic failure.Results. Our results demonstrate that (i) GSCs located in the SVZ are specifically resistant to radiation in vivo, (ii) these cells display enhanced mesenchymal roots that are known to be associated with cancer radioresistance, (iii) these mesenchymal traits are specifically upregulated by CXCL12 (stromal cell-derived factor-1) both in vitro and in the SVZ environment, (iv) the amount of SVZ-released CXCL12 mediates GBM resistance to radiation in vitro, and (v) interferes with the CXCL12/CXCR4 signalling system, allowing weakening of the tumor mesenchymal roots and radiosensitizing SVZ-nested GBM cells. Conclusion. Together, these data provide evidence on how the adult SVZ environment, through the release of CXCL12, supports GBM therapeutic failure and potential tumor relapse. Key wordsCXCL12 | glioblastoma | mesenchymal activation | radioresistance | subventricular zone Primary brain tumors are considered as one of the nastiest scourges faced in oncology. Their most aggressive form, glioblastoma (GBM, WHO grade IV), is also regarded as the most common and lethal subtype. 1 Patients' poor survival rates are typically correlated with unsatisfactory therapeutic strategies leading to systematic GBM relapses. 2 Trying to better

Taken together, these data demonstrate the significant role of the CXCL12/CXCR4 signaling in this original model of brain cancer invasion.

Cell migration is an important process that occurs during development and has also been linked to the motility of cancer cells. Cytoskeleton reorganization takes place in the migration process leading to lamellipodia formation. Understanding the molecular underpinnings of cell migration is particularly important in studies of glioblastoma, a highly invasive and aggressive cancer type. Two members of the phosphoinositide 5‐phosphatase family, SKIP and SHIP2, have been associated with cell migration in glioblastoma; however, the precise role these enzymes play in the process—and whether they work in concert—remains unclear. Here, we compared phosphoinositide 5‐phosphatases expression in glioblastoma primary cells and cell lines and showed that SHIP2 and SKIP expression greatly varies between different cell types, while OCRL, another phosphoinositide 5‐phosphatase, is constitutively expressed. Upon adhesion of U‐251 MG cells to fibronectin, SHIP2, SKIP, and PI(4,5)P2 colocalized in membrane ruffles. Upregulation of PI(4,5)P2 was observed in SKIP‐depleted U‐251 MG cells compared to control cells, but only when cells were adhered to fibronectin. Both PTEN‐deficient (U‐251) and PTEN‐containing (LN229) glioblastoma cells showed a decrease in cell migration velocity in response to SKIP downregulation. Moreover, a SHIP2 catalytic inhibitor lowered cell migration velocity in the U‐251 MG cell line. We conclude that integrin activation in U‐251 cells leads to colocalization of both SKIP and SHIP2 in ruffles, where they act as potential drivers of cell migration. Depending on their expression levels in glioblastoma, phosphoinositide 5‐phosphatases could cooperate and synergize in the regulation of cell migration and adhesion.