This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Winters, W. D. Articles by Morton, D. L. Search for Related Content PubMed PubMed Citation Articles by Winters, W. D. Articles by Morton, D. L.

Differential Effects of Rifampicin on Cultured Human Tumor Cells¹

Division of Oncology, Department of Surgery, UCLA School of Medicine, Los Angeles, California 90024

Rifampicin, its derivative N-demethylrifampicin, and adriamycin were examined for their effects on the viability of normal and malignant human cells. Dose-response curves were determined by the outgrowth of viable cell clones in vitro following exposure to each of the drugs.

Human sarcoma and melanoma cells were most sensitive to rifampicin exposure at concentrations of 5 to 20 µg/ml, while normal, cervical carcinoma, and bladder carcinoma cells were remarkably less responsive. Rifampicin dose-response curves differed in slope for each type of sensitive tumor cells, suggesting differences in drug uptake or in cellular metabolism. The high sensitivity of sarcoma and melanoma cells was not related to the number of cells exposed per drug dose or to the absolute plating efficiencies or cell generation times of the cells.

In contrast, normal and tumor cells showed few differences in response to exposure with N-demethylrifampicin or adriamycin. Our results suggest that the cell cloning techniques described can be used to study the growth-inhibitory properties of drugs in vitro and to screen potential antitumor agents for in vivo treatment.

¹ This investigation was supported in part by USPHS Research Grants CA 12582, CA 05252, and CA 12285 and grants from the California Institute for Cancer Research, American Cancer Society, and Surgical Services, Sepulveda Veterans Hospital.

² To whom reprint requests should be addressed.

Received 5/ 9/74. Accepted 7/29/74.