Long non-coding RNA in glioblastoma invasion: Angiogenesis and mesenchymal transition via PI3K and Wnt signalling

Glioblastoma (GBM) is the deadliest type of primary brain tumours with a high mortality rate, attributing to high post-surgical tumour recurrence. This unfavourable prognosis is due to the highly invasive phenotype observed in GBM cells, especially within the mesenchymal (MES) subtype of GBM. In recent years, the involvement of non-coding RNA (ncRNA) such as long non-coding RNA (lncRNA) and microRNA (miRNA) have been extensively deliberated in cancers and GBM. They were reported to be involved in the regulation of multiple biological pathways and cellular processes, which leads to increased cell invasion observed in tumours. This review focuses on two cellular processes; angiogenesis and MES transition, which can stimulate the invasive nature of GBM cells. Additionally, the extracellular matrix (ECM) and the hypoxic environment of GBM microenvironment which are central factors regulating both cellular processes will be discussed. Both cellular processes affiliated with cell invasion are downstream of signalling pathways such as PI3K/Akt or Wnt/β-catenin signalling, which will also be elaborated. Finally, recent studies characterising novel lncRNAs in the regulation of cell-invasion in GBM, specifically via the biological processes and signalling pathways discussed previously will be compiled and reviewed.