Establishment of human squamous carcinoma cell lines highly and minimally sensitive to bleomycin and analysis of factors involved in the sensitivity

Abstract

Human squamous carcinoma cell lines that were highly and minimally sensitive to bleomycin were established from clinical specimens and designated as SCCKN and SCCTF, respectively. Although these cell lines showed a similar growth doubling time in vitro, SCCTF was approximately ten times less sensitive to bleomycin than SCCKN. The bleomycin high and low sensitivities were stable even at the 70‐cell passage level in vitro. In addition, nude mouse tumors produced by SCCTF were less sensitive to bleomycin than those produced by SCCKN, and the ratio of the mean tumor weight in bleomycin‐treated mice to that in control mice was 89.2% in SCCTF and 18.8% in SCCKN. As compared with SCCKN, SCCTF also was less sensitive to peplomycin (5‐fold), mitomycin C (2.3‐fold), cisdiammine dichloroplatinum (2.5‐fold), and vincristine (6.5‐fold). Analyses of low bleomycin sensitivity showed that SCCTF had an approximately 20% decreased cellular accumulation and retention of bleomycin, 1.2‐fold increase of bleomycin hydrolase activity, elevated DNA repair activity, and increased poly(adeno‐sine diphosphate‐ribose) polymerase activity as compared with SCCKN. Copyright © 1992 American Cancer Society