In vitro and in vivo induction of squamous cell carcinoma antigen (SCC) in a uterine cervical cancer cell line (SKG-IIIa) with peplomycin and sodium butyrate.

In order to investigate the effect of an antisquamous cell carcinoma drug, peplomycin, the new analogue of bleomycin, on the production of a squamous cell carcinoma-associated tumor marker termed "SCC" (or TA-4), we carried out in vitro and in vivo experiments using the uterine cervical epidermoid cancer cell line SKG-IIIa, together with the investigation of the effect of sodium butyrate which was reported to be one of the representative gene modulators. In vitro production of SCC was biochemically and immunocytochemically confirmed in SKG-IIIa cells. Immunocytochemistry using anti-SCC antibody revealed that the total number of SCC-positive cells increased after the treatment with peplomycin (1.6 fold) or sodium butyrate (1.5 fold). The total amount of SCC in cultured medium, intracellular SCC, and cell debris during 5 days of culturation also increased with peplomycin (1.8 fold) and sodium butyrate (1.4 fold). These data strongly suggest that SCC production of SKG-IIIa cells is stimulated by peplomycin and sodium butyrate in vitro. In vivo experiments were also performed by administering peplomycin to nude rats with heterotransplanted tumors of SKG-IIIa, and transient elevations of serum SCC level (113% to 238% of the initial values) were observed, suggesting that SCC production of cancer cells is also stimulated by peplomycin in vivo.