Glioma oncogenesis and animal models of glioma formation

Cytotoxic potential of three Sabal species grown in Egypt: a metabolomic and docking-based study

The phytochemical profiles of leaves and pollen grains' extracts of S. causiarum, S. palmetto and S. yapa were investigated and characterised by LC-HR-MS-based metabolomic analysis. Further, biomarker metabolites were determined using multivariate and clustering analysis. S. causiarum leaves extract along with both S. palmetto and S. yapa pollen grains extracts showed interesting in vitro cytotoxic activity using MTT assay against PC-3 cell lines. While, both S. yapa leaves and pollen grains-derived extracts and S. causiarum pollen grains-derived extracts were active against A-172 cell line. OPLS-DA models was generated, to putatively determine the most active cytotoxic metabolites, these models suggested that alkaloids, flavonoids and phenolic acids are the most important metabolites in the active extracts. In silico analysis (neural-networking-based activity prediction and docking studies) of these top-scoring metabolites further supported OPLS-DA models predictability. This study could be considered as primary step in the in-depth exploration of bioactive natural products from Sabal.

Constitutive activation of Raf-1 induces glioma formation in mice

In human glioblastoma multiforme (GBM), RAS activity is upregulated in the majority of the tumors. Furthermore, the levels of phospho-mitogen-activated protein kinase/extracellular signal regulated kinase (MAPK/ERK), a downstream effector of RAS, are also increased. In mice, activated KRas cooperates with the loss of INK4a-ARF locus or with activated Akt to induce gliomas, confirming an important role for this pathway in glioma biology. However, to correctly target therapies against the RAS signaling pathway, it is necessary to identify the effectors that contribute to RAS-mediated gliomagenesis. In this study, we investigated the contribution of RAF signaling in glioma oncogenesis. We find that the levels of RAF-1 and BRAF proteins and RAF kinase activity are increased in human GBM samples. We confirm the importance of this finding by demonstrating a causal role for a constitutively active Raf-1 mutant in glioma formation in mice. Specifically, we find that activated Raf-1 cooperates with Arf loss or Akt activation to generate gliomas similar to activated KRas under the same conditions. Our study suggests that the oncogenic effect of KRas in glioma formation may be transduced at least in part through Raf signaling and that therapeutic targeting of this pathway may be beneficial in glioma treatment.

Establishment of a new human glioblastoma multiforme cell line (WJ1) and its partial characterization

(1) A new human glioblastoma multiforme (GBM) cell line, WJ1, was established from the tissue derived from a 29-year-old patient diagnosed with a grade IV GBM. (2) The WJ1 cell line has been subcultured for more than 80 passages in standard culture media without feeder layer or collagen coatings. (3) GBM cells grow in vitro with distinct morphological appearance. Ultrastructural examination revealed large irregular nuclei and pseudo-inclusion bodies in nuclei. The cytoplasm contained numerous immature organelles and a few glia filaments. Growth kinetic studies demonstrated an approximate population doubling time of 60 h and a colony forming efficiency of 4.04%. The karyotype of the cells was hyperdiploid, with a large subpopulation of polyploid cells. Drug sensitivities of DDP, VP-16, tanshinone IIA of this cell line were assayed. They showed a dose- and time-dependent growth inhibition effect on the cells. (4) Orthotopic transplantation of GBM cells into athymic nude mice induced the formation of solid tumor masses about 6 weeks. The cells obtained from mouse tumor masses when cultivated in vitro had the same morphology and ultrastructure as those of the initial cultures. (5) This cell line may provide a useful model in vitro and in vivo in the cellular and molecular studies as well as in testing novel therapies for human glioblastoma multiforme.