Loss of Collapsin Response Mediator Protein1, as Detected by iTRAQ Analysis, Promotes Invasion of Human Gliomas Expressing Mutant EGFRvIII

Abstract

Glioblastoma multiforme (GBM) is the most common and lethal primary human brain tumor. GBMs are characterized by a variety of genetic alterations, among which oncogenic mutations of epidermal growth factor receptor (EGFRvIII) is most common. GBMs harboring EGFRvIII have increased proliferation and invasive characteristics versus those expressing wildtype (wt) EGFR. To identify the molecular basis of this increased tumorgenic phenotype, we used iTRAQ-labeling differential proteomic analysis. Among several differentially expressed proteins, we selected CRMP1, a protein implicated in cellular invasion that was markedly decreased in GBMs expressing EGFRvIII, for further study. The differential expression of CRMP1 was confirmed in a panel of human GBM cell lines and operative specimens that express wtEGFR or mutant EGFRvIII by quantitative real-time PCR, Western blot, and immunohistochemical analysis. In human GBM samples, decreased expression of CRMP1 correlated with EGFRvIII positivity. Knockdown of CRMP1 by siRNA resulted in increased invasion of wtEGFR expressing human GBM cells (U87 and U373) to those found in isogenic GBM cells. Exogenous expression of EGFRvIII in these wtEGFR-expressing GBM cells promoted their ability to invade and was accompanied by decreased expression of CRMP1. Rescuing CRMP1 expression decreased invasion of the EGFRvIII-expressing GBM cells by tilting the balance between Rac and Rho. Collectively, these results show that the loss of CRMP1 contribute to the increased invasive phenotype of human GBMs expressing mutant EGFRvIII. [Cancer Res 2009;69(22):8545-54]

Glioblastoma cellular architectures are predicted through the characterization of two-cell interactions

“…Using data recorded from isolated single cells for comparison, the twocell data exhibits clear repression of EGFR signaling at small cell separations (<80 μm), and elevated EGFR signaling at larger separations (>100 μm) (12). Elevated levels of phosphoproteins downstream of EGFR have been associated with enhanced tumorigenicity and motility (2,(5)(6)(7)(8). Thus, the data implies a relationship between tumorigenic activity and cell separation.…”

“…In every biological replicate 900 ≤ N ≤ 1,900 cell pairs were found that had a separation distance of ≤200 μm and were used to calculate RDF and uðrÞ functions. in increased downstream signaling (21) and enhanced invasiveness and cell motility (2,7,22). Recently, a unidirectional cross-talk between EGFRvIII+ and wtEGFR cells was revealed within a heterogeneous GBM tumor; EGFRvIII+ cells were able to induce EGFR signaling through IL-6 in U87wtEGFR cells but not vice versa (1).…”

“…EGFR signaling plays an important role in motility and promoting tumor growth within EGFRvIII+ GBM tumors (2,(5)(6)(7)(8).…”

Rare autosomal copy number variations in early-onset familial Alzheimer’s disease

“…43 CRMP1 has a role in SEMA3A-(a gene associated with AD 44 ) mediated regulation of neural growth and axonal guidance, and microtubule assembly. 43,[45][46][47] Considering the role of CRMPs in axonal guidance and regeneration in the brain, gain in CRMP1 could compromise neuroplasticity with aging and thus lead to AD. Interestingly, CRMP2 has been reported to be hyper-phosphorylated as an early event in AD pathogenesis.…”

Collapsin Response Mediator Protein 4 Expression is Associated with Liver Metastasis and Poor Survival in Pancreatic Cancer

“…11-18 CRMP1 suppressed invasion and was correlated with clinical outcomes in non-small cell lung cancer and glioblastoma. [12][13][14][15] Gao et al 18 found that CRMP4 expression was inversely associated with lymph node metastasis from prostate cancer. In vitro studies of pulmonary cancer showed that Sema3A was endowed with putative antitumor activity.…”