Targeting the mDia Formin-Assembled Cytoskeleton Is an Effective Anti-Invasion Strategy in Adult High-Grade Glioma Patient-Derived Neurospheres

Abstract

High-grade glioma (HGG, WHO Grade III–IV) accounts for the majority of adult primary malignant brain tumors. Failure of current therapies to target invasive glioma cells partly explains the minimal survival advantages: invasive tumors lack easily-defined surgical margins, and are inherently more chemo- and radioresistant. Much work centers upon Rho GTPase-mediated glioma invasion, yet downstream Rho effector roles are poorly understood and represent potential therapeutic targets. The roles for the mammalian Diaphanous (mDia)-related formin family of Rho effectors have emerged in invasive/metastatic disease. mDias assemble linear F-actin to promote protrusive cytoskeletal structures underlying tumor cell invasion. Small molecule mDia intramimic (IMM) agonists induced mDia functional activities including F-actin polymerization. mDia agonism inhibited polarized migration in Glioblastoma (WHO Grade IV) cells in three-dimensional (3D) in vitro and rat brain slice models. Here, we evaluate whether clinically-relevant high-grade glioma patient-derived neuro-sphere invasion is sensitive to formin agonism. Surgical HGG samples were dissociated, briefly grown as monolayers, and spontaneously formed non-adherent neuro-spheres. IMM treatment dramatically inhibited HGG patient neuro-sphere invasion, both at neuro-sphere embedding and mid-invasion assay, inducing an amoeboid morphology in neuro-sphere edge cells, while inhibiting actin- and tubulin-enriched tumor microtube formation. Thus, mDia agonism effectively disrupts multiple aspects of patient-derived HGG neuro-sphere invasion.

Multiple formin proteins participate in glioblastoma migration

“…This was additionally accompanied by a shift in morphology with mDia2 knockdown. Migrating glioblastoma cells lost extensions and mesenchymal morphology, similar to findings reported with IMM2 treatment [19]. Compared to mDia1 and mDia2, we found that FHOD1 knockdown had similar effect on migration.…”

“…They found that the molecule IMM2 efficiently reduced the single cell migration from the neurosphere core. IMM2 treatment caused a morphologic shift toward ameboid morphology, also inhibiting the formation of microtubes [19]. Microtubes are recently found cellular extensions in glioblastoma, that keep glioblastoma cells connected as a network while migrating [5].…”

“…Therefore, we decided to study whether the basal expression of formins FHOD1 and INF2 is necessary for migration, using siRNA mediated knockdown. As formins mDia1 and mDia2 have earlier been shown to participate in glioblastoma migration [17][18][19], we decided to include knockdown of these formins in our experiments. The expression of the formins was individually knocked down in glioblastoma cell lines U87, U138, T86, and UTGB7.…”

Screening and functional prediction of differentially expressed circular RNAs in human glioma of different grades

“…However, the top three pathways were cellular responses to stress, transcriptional regulation by RUNX1, and transcriptional regulation by MECP2 in the Reactome pathway analyses of target genes. We noted that the Rho GTPase pathway has been shown to be associated with infiltrative growth and invasion of glioblastoma [ 38 , 39 ]. In addition, RUNX1 is considered to a key factor participating in the malignant biological behavior of glioma cells [ 40 ].…”

FAM172A suppresses polymerization of tubulin and development of HCC (Hepatocellular Carcinoma)

“…The another is MTs stabilizers, which combines the polymerized heterodimer of α, β-tubulin with high a nity [7]. The polymerization of tubulin exhibit the key role in development and metastasis of HCC [8][9][10][11][12].…”