Dataset Information

Major vault protein supports glioblastoma survival and migration by upregulating the EGFR/PI3K signalling axis.

ABSTRACT: Despite their ubiquitous expression and high conservation during evolution, precise cellular functions of vault ribonucleoparticles, mainly built of multiple major vault protein (MVP) copies, are still enigmatic. With regard to cancer, vaults were shown to be upregulated during drug resistance development as well as malignant transformation and progression. Such in a previous study we demonstrated that human astrocytic brain tumours including glioblastoma are generally high in vault levels while MVP expression in normal brain is comparably low. However a direct contribution to the malignant phenotype in general and that of glioblastoma in particular has not been established so far. Thus we address the questions whether MVP itself has a pro-tumorigenic function in glioblastoma. Based on a large tissue collection, we re-confirm strong MVP expression in gliomas as compared to healthy brain. Further, the impact of MVP on human glioblastoma aggressiveness was analysed by using gene transfection, siRNA knock-down and dominant-negative genetic approaches. Our results demonstrate that MVP/vaults significantly support migratory and invasive competence as well as starvation resistance of glioma cells in vitro and in vivo. The enhanced aggressiveness was based on MVP-mediated stabilization of the epidermal growth factor receptor (EGFR)/phosphatidyl-inositol-3-kinase (PI3K) signalling axis. Consequently, MVP overexpression resulted in enhanced growth and brain invasion in human glioblastoma xenograft models. Our study demonstrates, for the first time, that vaults have a tumour-promoting potential by stabilizing EGFR/PI3K-mediated migration and survival pathways in human glioblastoma.

SUBMITTER: Lotsch D

PROVIDER: S-EPMC3875758 | biostudies-literature | 2013 Nov

REPOSITORIES: biostudies-literature

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Major vault protein supports glioblastoma survival and migration by upregulating the EGFR/PI3K signalling axis.

Lötsch Daniela D Steiner Elisabeth E Holzmann Klaus K Spiegl-Kreinecker Sabine S Pirker Christine C Hlavaty Juraj J Petznek Helga H Hegedus Balazs B Garay Tamas T Mohr Thomas T Sommergruber Wolfgang W Grusch Michael M Berger Walter W

Oncotarget 20131101 11

Despite their ubiquitous expression and high conservation during evolution, precise cellular functions of vault ribonucleoparticles, mainly built of multiple major vault protein (MVP) copies, are still enigmatic. With regard to cancer, vaults were shown to be upregulated during drug resistance development as well as malignant transformation and progression. Such in a previous study we demonstrated that human astrocytic brain tumours including glioblastoma are generally high in vault levels while ...[more]

PMID: 24243798

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Project description:ObjectivesHyperinsulinemia is a risk factor for pancreatic cancer, but the function of insulin in carcinogenesis is unclear, so this study aimed to elucidate the carcinogenic effects of insulin and the synergistic effect with the KRAS mutation in the early stage of pancreatic cancer.Materials and methodsA pair of immortalized human pancreatic duct-derived cells, hTERT-HPNE E6/E7/st (HPNE) and its oncogenic KRASG12D variant, hTERT-HPNE E6/E7/KRASG12D /st (HPNE-mut-KRAS), were used to investigate the effect of insulin. Cell proliferation, migration and invasion were assessed using Cell Counting Kit-8 and transwell assays, respectively. The expression of E-cadherin, N-cadherin, vimentin and matrix metalloproteinases (MMP-2, MMP-7 and MMP-9) was evaluated by Western blotting and/or qRT-PCR. The gelatinase activity of MMP-2 and MMP-9 in conditioned media was detected using gelatin zymography. The phosphorylation status of AKT, GSK3?, p38, JNK and ERK1/2 MAPK was determined by Western blotting.ResultsThe migration and invasion ability of HPNE cells was increased after the introduction of the mutated KRAS gene, together with an increased expression of MMP-2. These effects were further enhanced by the simultaneous administration of insulin. The use of MMP-2 siRNA confirmed that MMP-2 was involved in the regulation of cell invasion. Furthermore, there was a concentration- and time-dependent increase in gelatinase activity after insulin treatment, which could be reversed by an insulin receptor tyrosine kinase inhibitor (HNMPA-(AM)3 ). In addition, insulin markedly enhanced the phosphorylation of PI3K/AKT, p38, JNK and ERK1/2 MAPK pathways, with wortmannin or LY294002 (a PI3K-specific inhibitor) and PD98059 (a MEK1-specific inhibitor) significantly inhibiting the insulin-induced increase in MMP-2 gelatinolytic activity.ConclusionsTaken together, these results suggest that insulin induced migration and invasion in HPNE and HPNE-mut-KRAS through PI3K/AKT and ERK1/2 activation, with MMP-2 gelatinolytic activity playing a vital role in this process. These findings may provide a new therapeutic target for preventing carcinogenesis and the evolution of pancreatic cancer with a background of hyperinsulinemia.

Dataset Information

Major vault protein supports glioblastoma survival and migration by upregulating the EGFR/PI3K signalling axis.

Publications

Major vault protein supports glioblastoma survival and migration by upregulating the EGFR/PI3K signalling axis.

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