Proscillaridin A exerts anti-tumor effects through GSK3β activation and alteration of microtubule dynamics in glioblastoma

Abstract

Glioblastoma (GBM) is characterized by highly aggressive growth and invasive behavior. Due to the highly lethal nature of GBM, new therapies are urgently needed and repositioning of existing drugs is a promising approach. We have previously shown the activity of Proscillaridin A (ProA), a cardiac glycoside inhibitor of the Na(+)/K(+) ATPase (NKA) pump, against proliferation and migration of GBM cell lines. ProA inhibited tumor growth in vivo and increased mice survival after orthotopic grafting of GBM cells. This study aims to decipher the mechanism of action of ProA in GBM tumor and stem-like cells. ProA displayed cytotoxic activity on tumor and stem-like cells grown in 2D and 3D culture, but not on healthy cells as astrocytes or oligodendrocytes. Even at sub-cytotoxic concentration, ProA impaired cell migration and disturbed EB1 accumulation at microtubule (MT) plus-ends and MT dynamics instability. ProA activates GSK3β downstream of NKA inhibition, leading to EB1 phosphorylation on S155 and T166, EB1 comet length shortening and MT dynamics alteration, and finally inhibition of cell migration and cytotoxicity. Similar results were observed with digoxin. Therefore, we disclosed here a novel pathway by which ProA and digoxin modulate MT-governed functions in GBM tumor and stem-like cells. Altogether, our results support ProA and digoxin as potent candidates for drug repositioning in GBM.

EB1-dependent long survival of glioblastoma-grafted mice with the oral tubulin-binder BAL101553 is associated with inhibition of tumor angiogenesis

“…Through its C-terminal part, EB1 interacts with numerous partners at growing MT ends to form molecular networks that contribute to the regulation of MT dynamic instability and regulate MT functions [37]. In addition, the amount of EB1 influences the way MT dynamic instability is altered [38] and posttranslational modifications of EB1 also modulate the regulation of MT dynamics, proliferation /migration and subsequent MTA response [23,38,39]. Interestingly, www.oncotarget.com VEGF suppressed MT dynamics in living HUVECs, induced EB1 C-terminal detyrosination and increased EB1 comet length.…”

The Organoid Era Permits the Development of New Applications to Study Glioblastoma

“…They mirror a realistic in vitro scenario of tumor growth and invasion [50]. Furthermore, they are widely adopted for high-throughput drug screening since they are easy to handle and engineer [50][51][52]. Spheroids are usually derived from GB cell lines growing as spheres in a 3D matrix or in suspension.…”

Modeling invasion patterns in the glioblastoma battlefield

“…In particular, increased MMP levels and tumor invasiveness in human GBs show a strong correlation (12,30,31). Several studies reported their localization in TM membrane (32,33), especially for MMP-2 and MT1-MMP.Our interest arises from the analysis of the role of TMs in tumor progression and of the effect of different drugs on their structures and dynamics (34,35). The inhibition of TMs leads to a decrease in cell migration and proliferation, with obvious consequences on GB treatment (34)(35)(36).…”

“…Several studies reported their localization in TM membrane (32,33), especially for MMP-2 and MT1-MMP.Our interest arises from the analysis of the role of TMs in tumor progression and of the effect of different drugs on their structures and dynamics (34,35). The inhibition of TMs leads to a decrease in cell migration and proliferation, with obvious consequences on GB treatment (34)(35)(36). The process of growth and retraction of TMs plays a fundamental role for cell-to-cell communication routing (17,18,(20)(21)(22)(23), as well as a transient binding platform for essential proteins that regulate tumor dynamics (37).…”

“…Our interest arises from the analysis of the role of TMs in tumor progression and of the effect of different drugs on their structures and dynamics (34,35). The inhibition of TMs leads to a decrease in cell migration and proliferation, with obvious consequences on GB treatment (34)(35)(36).…”