Glioblastoma cell lines derived under serum-free conditions can be used as an in vitro model system to evaluate therapeutic response

We provide evidence that six glioblastoma cell lines derived and maintained under serum-free conditions secrete VEGF and four also expressed VEGFR2. Expression of VEGFR2 was associated with reduced proliferation in response to anti-VEGF antibodies. Spontaneous loss of VEGFR2 over passage was associated with loss of this anti-proliferative effect. Gain of expression of VEGFR2 was not associated with the acquisition of responsiveness to anti-VEGF antibodies. Secretion of PDGF was absent in 5/6 of our cell lines and none of the cell lines had reduced proliferation in response to anti-PDGF antibodies suggesting that PDGF autocrine signalling was unlikely to be significant in tumour proliferation. These data are consistent with published clinical trials suggesting that glioblastoma cell lines derived under serum-free conditions have the potential for use in drug screening and individualising patient therapy.