Wenjun Pu
The University of Queensland School of Pharmacy, Australia.
Title: Pressure induces glioblastoma invasiveness
Biography
Biography: Wenjun Pu
Abstract
Introduction. Glioblastoma (GBM) is a type of brain tumour with high invasiveness and poor prognosis. Both hydrostatic and osmotic pressures are altered in the GBM tumour microenvironment. We hypothesize that increased hydrostatic and osmotic pressures upregulate glioblastoma invasiveness. Better understanding of the molecular and cellular mechanisms linking pressure increases to GBM invasiveness may help develop innovative therapeutic approaches.
Aims: To evaluate the effect of hydrostatic and osmotic pressure on GBM invasive potential.
Methods: The hydrostatic pressure was increased via air pressure in cell culture flasks to 30 mmHg. The osmotic pressure of GBM cell culture medium was adjusted using sodium chloride or water. Cells were incubated in serum-free medium with varying osmolality (from 260 to 440 mOsm) or under increased hydrostatic pressure (30 mmHg) for 48 hours. Cell viability was measured using the MTT assay. The proteolytic profile and epithelial-mesenchymal transition (EMT) were investigated using in-gel zymography and real-time qPCR. The EMT markers assessed were snail-1, slug, twist, vimentin and N-cadherin. Invasion was investigated in vitro using Transwell™ inserts coated with basement membrane-like protein.
Results: Raised hydrostatic pressure resulted in increased expression of urokinase-type plasminogen activator (uPA) and several EMT markers in GBM cell lines U87 and U251. In response to osmotic stress, U87 and U251 cell lines upregulated the expression of uPA and matrix metalloproteinases (MMPs) well as some of the EMT markers tested.
Discussion. Our findings suggest that GBM respond to two types of pressure stress by increasing matrix-degrading enzyme production, and adopting a gene expression phenotype reminiscent of EMT.