This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services 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 Ebina, T. Articles by Ishida, N. Search for Related Content PubMed PubMed Citation Articles by Ebina, T. Articles by Ishida, N.

Inhibition of Formation of Microtubular Paracrystals in HeLa-S3 Cells by Neocarzinostatin¹

Department of Bacteriology, Tohoku University School of Medicine, 2-1, Seiryo-machi, Sendai 980, Japan

The effect of an antitumor antibiotic, neocarzinostatin (NCS), on the formation of microtubular paracrystals (PC) induced by vinblastine sulfate, 10 µg/ml, in HeLa-S3 cells was examined by phase-contrast microscopy. The pretreatment of HeLa-S3 cells with NCS, 5 to 50 µg/ml, for 4 hr prevented the PC formation, and there was a dose response of NCS to the degree of inhibition. When the same inhibitory effect on PC formation was examined with other antitumor agents at high doses (50 µg/ml), colchicine was found to be one of the most effective agents, like NCS. Puromycin, antimycin, adriamycin, cytochalasin B, and cycloheximide revealed moderate activity, and the other antibiotics, such as mitomycin C, bleomycin, and rifampicin, did not show any effect at all. NCS was a unique antibiotic that inhibited PC formation among inhibitors of DNA synthesis. It was suggested that NCS affects the microfibrillar-microtubular proteins system in vivo, resulting in the inhibitions of organization of spindle fibers from microtubules at the G₂ phase in HeLa cells.

¹ This investigation was supported in part by a grant from the Ministry of Education and the Ministry of Health and Welfare of Japan.

Received 6/23/75. Accepted 8/26/75.