Published in Cancer Detection and Prevention 2000; 24(Supplement 1).

The in vitro response of primary cultures of tumour material to DNA damage: comparison with that of established cell lines

BC Baguley PhD, ES Marshall NZCS

Auckland Cancer Society Research Centre, University of Auckland School of Medicine, Auckland, New Zealand,

AIMS: We wished to use short-term cultures of clinical tumour material to measure the effects of radiation and anticancer drugs. Since cytokinetic effects dominate the results of such assays, we compared responses to DNA damaging agents with that to the mitotic inhibitor paclitaxel. This allowed compensation for the wide differences in proliferation rates. We also compared results of primary cultures with those of a panel of cell lines. METHODS: Tumour tissue samples from over 100 patients with melanoma, gynaecological, head and neck and other cancers were cultured as small cellular aggregates. Cultures were irradiated or treated with cytotoxic drugs, incubated in agarose-coated 96-well plates for 7 days, and assayed by uptake of tritiated thymidine. Low passage tumour cell lines were assessed after growth for 1-5 days. Doubling times were estimated by a stathmokinetic method using paclitaxel. RESULTS: Time course and flow cytometric studies with established cell lines indicated that some lines, including two known to have intact p53 gene status, underwent G1-phase arrest after DNA damage. However, this effect reversed after 1-2 days. In contrast, some but not all of the primary cultures failed to show such reversal at 7 days, indicating either long term cycle arrest or induced cell loss. CONCLUSIONS: The behavior of primary cultures, as measured by this assay, differs significantly from that of cell lines and may indicate responses to DNA damaging agents that are not adequately modeled by cell lines. The results of short-term primary cultures suggest they may have predictive potential for clinical response. Supported by the Auckland Division of the Cancer Society of New Zealand.

KEY WORDS: cytokinetics, radiosensitivity, p53, paclitaxel, culture, apoptosis, cell cycle block.

For more information, contact

Paper presented at the International Symposium on Impact of Biotechnology on Cancer Diagnostic & Prognostic Indicators; Geneva, Switzerland; October 28 - 31, 2000; in the section on prognostic markers.