Malignant gliomas are highly proliferative and invasive neoplasms where total surgical

Malignant gliomas are highly proliferative and invasive neoplasms where total surgical resection is often impossible and effective local radiation therapy difficult. Exatecan mesylate machinery in GBM. [10C13]. CFL phosphorylation is dynamically regulated by LIM kinases (LIMK) and testis-specific kinases (TESK1 and TESK2) that phosphorylate CFL at serine-3 (S3) residues that inactivate CFL by blocking CFL’s actin binding ability [14C16]. The phosphatases Slingshot and Chronophilin activate CFL through localization dependent dephosphorylation [17]. The factors known to phosphorylate and dephosphorylate CFL to enable CFL to work on downstream effector molecules leading to cell migration collectively comprise the CFL pathway. Given that LIMK1 is a downstream effector of both the Rac and Rho pathways, which respectively regulate mesenchymal and amoeboid migration, LIMK is likely a key regulator in both modes of cell migration. Interestingly, abnormal expression of LIMK has been implicated in numerous malignancies such as prostate cancer, invasive breast cancer and melanoma [18C21]. In the current study, we identified aberrant LIMK in a gene expression array of invasion/migration genes comparing normal brain to samples from highly malignant and invasive GBM. Here we investigate the role of LIMK in GBM migration and invasion and evaluate if LIMK small molecule inhibitors are viable candidates for preclinical targeting of GBM invasiveness. To our knowledge, an in-depth study of the role Rabbit Polyclonal to SEPT7 of LIMK in glioma motility and invasion has not been performed previously. RESULTS Identification of Cofilin pathway dysregulation in GBM Using gene-expression data from The Cancer Genome Atlas data set (TCGA) on the Affymetrix U133 platform we performed microarray analysis comparing 10 Exatecan mesylate normal brain samples versus 51 mesenchymal GBMs. We initially selected one subtype of GBM, the mesenchymal GBM, in our discovery screen to reduce the impact of GBM subtype heterogeneity. The mesenchymal subtype also lacks immediate actionable targets, and is associated with a poor prognosis [22C24]. We compared 400 invasion/migration genes C using the gene-ontology terms invasion and migration C represented by 700 probe-sets. We identified over 141 significant genes with a 1.5 fold change (p-value < 0.05, Exatecan mesylate and a false discovery rate q < 0.05) compared to normal brain (Figure ?Figure1A1A). Of the 141 genes, the cofilin pathway, which disassembles actin filaments (namely LIMK1, LIMK2, CFL, CAP1) was highly upregulated compared to normal brain (Figure ?Figure1B,1B, P<0.05). Of great interest we identified up-regulation of LIM domain kinase 1 and 2 (LIMK1/2) that phosphorylates and inactivates CFL in an additional data set comparing normal brain to GBM (Figure ?Figure1C1C). Lastly, we observed robust expression Exatecan mesylate of LIMK1 in several well-characterized GBM cell lines (U87, T98G and U118) and phospho-CFL in cell lines that expressed LIMK1 (Figure ?Figure1D1D). All phospho-CFL lines expressed LIMK1, but we did not observe phospho-CFL positive cell lines that were LIMK1 negative (Figure ?(Figure1D1D). Open in a separate window Figure 1 Identification of Cofilin pathway dysregulation in GBM(A) 700 Probe sets were investigated representing 400 genes involved in migration and invasion. Using Sam-Pairwise analysis, a fold change of 1 1.5 was used, p<0.05 and a Q value of <0.01. 141 Genes were identified as significantly up or down regulated compared in mesenchymal glioblastoma (n=51) versus normal brain (n=10) (B) Invasion Pathway Analysis identified significant deregulation of the Cofilin Pathway (C) LIMK1 and LIMK2 which phosphorylate CFL are up-regulated in GBM using the REMBRANDT brain tumor data set. (D) CFL is upregulated in GBM and LIMK1 and 2 are present in.