Drug sensitivity assay for leukaemic cells by flow cytometry.

BACKGROUND & OBJECTIVES: Drug sensitivity assays are useful in oncology practice for evaluating the sensitivity of malignant cells to anti-cancer drugs. The usefulness of such assays for the prediction of clinical response to therapy has also been demonstrated. The existing methods used for this purpose are time consuming and labour intensive. Here we report a simplified flow cytometry based assay for evaluating the in vitro drug sensitivity of leukaemic cells. METHODS: The chemo-sensitivity of three human leukaemic cell lines (a lymphoblastoid cell line, Jurkat; an erythroleukaemic cell line, K 562 and a myelomonocytic cell line HL-60) was investigated by flow cytometry. Flow cytometry was used to determine LD50 (50% inhibitory concentration) for prednisolone on Jurkat and daunorubicin on HL 60 and K 562 cell lines respectively. Per cent cell death could directly be assessed on a flow cytometer by measuring the fluorescence after staining with propidium iodide (PI). For comparison MTT assay was also performed using prednisolone on Jurkat and daunorubicin on HL-60. RESULTS: Cytotoxic effect of drugs was found to be dose dependent. Mean LD50 of prednisolone for Jurkat cells by flow cytometry was 0.805 +/- 0.058 mg/ml and by MTT assay 0.866 +/- 0.115 mg/ml. Mean LD50 of daunorubicin for HL-60 was 1.96 +/- 0.05 micrograms/ml by flow cytometry and 1.90 +/- 0.282 micrograms/ml by MTT assay. The mean LD50 of daunorubicin to K 562 was 0.49 +/- 0.049 mg/ml by the flow cytometry method. The inter-assay variation for the LD50 by flow cytometry based assay was found to be 6, 14 and 10 per cent for Jurkat, HL-60 and K 562 respectively. INTERPRETATION & CONCLUSION: We report a flow cytometry based drug-sensitivity assay for leukaemic cells, which uses a single dye staining and is rapid, technically simple and reproducible. The results compare well with the more commonly used MTT assay, which is labour intensive and time consuming. The limitation of our method is that it can only be used for studying cells in suspension and is therefore not suitable for adherent cell lines.

Avaliaçäo do potencial mutagênico-cancerígeno de fármacos pelo ensaio Salmonella/fraçäo microssomal: II. Mutagenicidade de antibióticos antineoplásicos do grupo das antraciclinas / Evaluation of the mutagenic carcinogenic potential of medicines by Salmonella microsome assay: II. Mutagenic activity of antineoplasic antibiotics from anthracycline group

Seis antibióticos do grupo das antraciclinas, produzidos por linhagens de Streptomyces isoladas no Brasil, foram testadas quanto a atividade mutagênica frente ao ensaio Salmonella/fraçäo microssomal (teste de Ames). Os resultados encontrados demonstram que todos os compostos säo fracamente mutagênicos para a linhagem indicadora de S. typhimurium TA102. Outro derivado antraciclínico, a daunorubicina, de amplo uso clínico, mostrou-se fortemente mutagênico para as linhagens TA102 e TA98. A exposiçäo da daunorubicina a luz e ao calor, tratamentos que inativam suas propriedades antineoplásicas, inibiram também seu efeito mitagênico. Os resultados apresentados sugerm que a determinaçäo da mutagenicidade em compostos do grupo das antraciclinas pode ser útil na identificaçäo e avaliaçäo de novos derivados com açäo antineoplásica