Clinical implications of hypoxia-inducible factor-1α and caveolin-1 overexpression in isocitrate dehydrogenase-wild type glioblastoma multiforme

Abstract

Glioblastoma multiforme (GBM) is the most common type of primary brain tumour in adults, and presents a very low survival rate. Isocitrate dehydrogenase (IDH)1/2 mutations have been found in ~12% of glioblastomas and are associated with long-term GBM survival. However, the risk factors that influence the prognosis of IDH-wild type GBM remain unclear. Hypoxia-inducible factor (HIF)-1α, an important oxygen-regulated transcription factor, has been demonstrated to serve a crucial role in tumour development and to be associated with a poor prognosis. In addition, caveolin-1 (CAV1) is a plasma membrane organizing protein, the expression of which can also be regulated by a hypoxic microenvironment. The present study therefore aimed to examine the expression levels of HIF-1α and CAV1, and their association with GBM prognosis. Reverse transcription-quantitative polymerase chain reaction and western blotting were performed to analyse the expression levels of HIF-1α and CAV1 in paired GBM tumour and adjacent non-tumour tissues. Immunohistochemistry was used to analyse the expression of the two proteins in paraffin-embedded tissues obtained from 42 patients with IDH-wild type GBM. Statistical analyses were performed to examine the correlation between HIF-1α and CAV1 expression and patient prognosis. The results revealed hat the expression levels of HIF-1α and CAV1 were upregulated in IDH-wild type GBM tissues compared to their paired non-tumour tissues (P<0.001). The expression of CAV1 was significantly correlated with high HIF-1α expression (P<0.01). In addition, overexpression of HIF-1α and CAV1 was markedly associated with a poor prognosis (P<0.001). In conclusion, HIF-1α and CAV1 may represent potential biomarkers for IDH-wild type GBM prognosis and potential targets for the development of therapies extending GBM survival.