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Abstract

To evaluate the hypothesis that co-implantation of different rodent glioma cell lines might result in experimental brain tumours that more closely resemble human gliomas the neuropathology and immunocytochemical features of implantation gliomas derived from single cell lines (C6, A15A5, F98), two cell lines admixed 50:50 prior to implantation (C6 + F98 and C6 + A15A5) and three cell lines equally admixed (C6 + A15A5 + F98) was studied in the adult Wistar rat. Tumours grew consistently following implantation of the single and the two admixed cell lines, however tumour growth following triple mix implantation was considerably and consistently impaired. The tumours derived from admixed cell lines showed regional heterogeneity with areas characteristic of both the primary cell lines. Foci of lymphocytic infiltrates, tumoural necrosis, often with pseudopallisading, and peritumoural edema were consistent features of all tumours. Limited parenchymal and more extensive perivascular tumoural invasion was seen predominantly in tumours containing the C6 cell line. There were no significant differences in GFAP, vimentin and HSP70 staining between the mixed tumours, although the pure F98 and A15A5 tumours were, unlike the pure C6 gliomas, S-100 negative. Using PCNA expression as a measure of the tumour proliferation all except the tumours derived from the three cell lines mix, which had a staining index of 7-10%, had focal staining indices in viable tumour of between 40-80%. There was focal positive staining in both perilesional brain and in regions of all tumours for the macrophage markers ED-1 and ED-2. None of the three cell lines stained in vitro for either ED1 and ED2 but all were constitutively positive in vitro for OX-6, a proposed marker for antigen presenting cells. The macrophage and lymphocytic response suggest a vigorous but largely ineffective immunological response had been mounted against all tumours. The consistent failure of the triple mix tumours to grow is unexplained. This work has shown the feasibility of producing 'mixed' cell line experimental gliomas by combining two cell lines at the time of innoculation. However, the relative failure to produce (i) mixed tumours that have properties not inherent to either parent cell line and (ii) implantation glioma with three cell lines suggest there are limits to this approach. Admixture of cell lines at the time of implantation therefore does not make experimental glioma models that more closely resemble natural gliomas, and also has some particular disadvantages. This experimental approach is therefore not recommended for use in the study of tumour biology and in evaluating the effectiveness of novel therapies.

Immunochemical Analysis of Glial Fibrillary Acidic Protein as a Tool to Assess Astroglial Reaction in Experimental C6 Glioma

“…GFAP-positivity of glioma cells was not observed at any terms of tumor development, which agrees with the data obtained by other researchers [14,20]. The volume of astrocytic border increased to postimplantation day 21 (56.6 mm 3 ), thereafter the number of the reactive astrocytes decreased.…”

“…These cells amounting to about 1 / 4 all glial cells are the fi rst to react to damage to the nervous tissue by active migration into the region of the pathological focus encompassing it with an astroglial border [14,20]. This universal defensive reaction accompanies almost all pathological processes in the brain.…”

Polysialic Acid Neural Cell Adhesion Molecule (PSA-NCAM) is an adverse prognosis factor in glioblastoma, and regulates olig2 expression in glioma cell lines

“…We chose C6 cells which displayed undetectable PSA-NCAM by ELISA or Western blot and show many features of GB tumors after intracranial injection such as an undifferentiated morphology [20], neovascularization [24], diffuse infiltrating borders and invasion of the surrounding tissue by isolated cells [25]. Moreover, PSA-NCAM forced expression in these cells has been shown to be associated with their increased migration when transplanted in mice [20].…”

Current Review of in Vivo GBM Rodent Models: Emphasis on the CNS-1 Tumour Model

“…Although originally developed in Wistar rats, C6 can be implanted in Sprague–Dawley and Long–Evans rats without rejection (Nagano et al, 1993; Whittle et al, 1998). Tumour cells are usually implanted into the fronto-parietal lobe at 1×10 5 cells in 5 μl, with variable rates of tumour take (Parsa et al, 2000; Branle et al, 2002).…”