Colony growth of normal and neoplastic cells in various concentrations of methylcellulose.

To assess the semisolid character of methylcellulose (MC) and its ability to prevent cell migration and aggregation in clonogenic assays, we studied the influence of various concentrations of MC (0.7%-1.26%) on colony growth of neoplastic cell lines, normal bone marrow cells, and hairy cell leukemia (HCL). All cell lines (K562, HL-60, JOK-1, Daudi, and BB3, an IgM-kappa B-cell line) showed a prominent decrease in colony numbers and remarkable changes in colony morphology at rising MC concentrations, whereas no such influence could be demonstrated for HCL, mixed lineage colony-forming units (CFU-GEMM), granulocyte-macrophage CFU (CFU-GM), erythroid burst-forming units (BFU-E), and erythroid CFU (CFU-E). Despite a decrease in colony numbers at high MC concentrations, some cell lines showed a sustained proliferation as measured by growth index calculations and bromodeoxyuridine (BrdUrd) incorporation. This indicates that at certain MC concentrations colony formation is not always a reflection of proliferation. BrdUrd incorporation yielded an extremely low proliferation capacity for HCL. It is likely that HCL cells, which strongly aggregate, formed pseudo-colonies in spite of high MC concentrations.

Comparison between clonogenic and cytotoxic assays for measuring LAK cell activity.

The antiproliferative effect of lymphokine-activated killer (LAK) cells was studied using a clonogenic assay in an attempt to find a model for predicting this effect in vivo or ex vivo (in the case of purging) in cancer treatment. The results were compared with the standard 51Cr-release cytotoxic assay. Cells from clonogenic neoplastic cell lines (K562 and HL-60) were plated in methylcellulose with LAK cells obtained from ten different donors in various effector-to-target (E:T) ratios. At E:T ratios of 16:1, elimination of greater than 90% of the clonogenic cells was seen in 20 of 21 experiments, whereas such lysis was incidentally found in the 51Cr-release assay. In almost all paired combinations, clonogenic cells tested in a colony assay were more sensitive to kill by LAK cells than the whole tumor cell suspensions measured in the 51Cr-release assay.