Published online Dec 12, 2015. doi: 10.5528/wjtm.v4.i3.78
Peer-review started: July 29, 2015
First decision: September 21, 2015
Revised: November 13, 2015
Accepted: December 1, 2015
Article in press: December 2, 2015
Published online: December 12, 2015
Processing time: 143 Days and 17.1 Hours
AIM: To determine the role for the intermediate filament protein nestin in glioma invasion.
METHODS: We examined the expression and function of nestin in gliomas (Grades II-IV as defined by the World Health Organization). We determined nestin expression using Immunohistochemical methods. To elucidate nestin’s biological function(s), we reduced mRNA levels by 61% and 87% in two glioblastoma-derived neurosphere lines using short hairpin RNAs and determined the effect of reduced nestin expression on glioma cell proliferation and invasion using MTS and matrigel migration assays, respectively. We also utilized quantitative real time polymerase chain reaction assays to determine the effect of reduced nestin expression on the expression of other markers associated with glioma stem cells and their differentiated progenies.
RESULTS: We found a significant correlation between nestin immunoreactivity and astrocytoma tumor grade, with 36% of grade II, 75% of grade III, and 100% of grade IV tumors expressing significant levels of the protein when assessed using immunohistochemistry. Reduction in nestin expression had no effect on cell growth in culture, but did retard the capacity of one line to migrate in-vitro on matrigel. Interestingly, in the line whose migration was not affected, mRNA levels of a second intermediate filament, synemin (also knowns as desmuslin), were elevated following introduction of shRNA targeting nestin. As synemin was not induced in the line which required nestin for migration, it is a possibility that synemin may compensate for the loss of nestin in this process.
CONCLUSION: Nestin expression is prominent in high-grade astrocytomas. Nestin is not required for cell growth but it may, however, be required for cell motility.
Core tip: Despite its common use as a marker of poorly differentiated stem and progenitor cells, the functional role of nestin in normal and neoplastic cells is poorly understood. Here we show that in gliomas, there is a significant positive correlation between nestin protein expression and increasing pathological grade. However, when nestin expression was inhibited, we found no significant effects on cell growth, expression of stem-cell markers, and the ability to initiate intracranial xenografts. Our data suggest that the functional role of nestin is limited, even though the migratory potential of some glioblastoma neurospheres is reduced by nestin knockdown.