REGULATION OF PROLIFERATION OF UM-SCV-1A AND UM-SCV-6 VULVAR CARCINOMA-CELLS BY CYTOKINES

The biology and pathogenesis of vulvar carcinoma are poorly understood at present. In order to understand this disease better, we have used recently developed squamous cell carcinoma lines of the vulva as model s. Two cell lines originating from two individuals (UM-SCV-1A and UM-S CV-6) were cultured in vitro in 10% fetal calf serum. The effects of i nterleukins 10 and 13, interferons alpha and gamma, granulocyte/macrop hage-growth-stimulating factor (GM-CSF), tumor necrosis factor alpha ( TNF alpha), and transforming growth factor beta (TGF beta) on the prol iferation of the cells was investigated by using radioactively labelle d uridine as tracer. In addition, an investigation on the molecular st ructure of extracted cellular DNA was carried out to investigate wheth er programmed cell death (apoptosis) would be inducible by any of the factors. In UM-SCV-1A cells, interleukin-10 (IL-10) and interleukin-13 (IL-13) caused an approximately 12-fold decrease in DNA synthesis in cells cultured for 72 h (P<0.001), while GM-CSF had no significant eff ect. TGF beta showed a significant inhibitory effect on deoxyuridine i ncorporation (P<0.001), which was 2.0- and 4.2-fold at 48 h and 72 h, respectively. TFG alpha showed a 1.2-fold inhibitory effect on DNA syn thesis at 48 h (P<0.01) and a 1.5-fold inhibition at 72 h (P<0.05). In terferon gamma (IFN gamma) showed an inhibitory effect on DNA synthesi s (1.3-fold; P<0.01). In UM-SCV-6 cells, both IL-10 and IL-13 showed i nhibitory effects on deoxyuridine incorporation (1.3- and 1.4-fold at 48 h, respectively; P<0.001) that were even more pronounced at 72 h (2 .4- and 2.5-fold respectively; P<0.001). IFN gamma caused a 3.6-fold i nhibition of DNA synthesis by UM-SCV-6 cells at 72 h (P<0.001). Both T FG beta and TNF alpha inhibited uridine incorporation (3.0- and 1.6-fo ld at 48 h, respectively; 2.7-fold at 72 h for both factors). GM-CSF i nhibited DNA synthesis by UM-SCV-6 cells 1.3- 2.0-fold at 48 h and 72 h, respectively. In dose/response analyses, the effect of INF alpha on DNA synthesis was inhibitory in both cell lines at 48 h, while stimul atory effects were observed at 72 h. Electrophoretic analyses of DNA i solated from cells cultured in the presence or absence of different fa ctors did not reveal DNA fragmentation. Ail cytokines, with the except ion of IFN alpha, showed inhibitory effects on DNA synthesis by vulvar carcinoma cells. Of the factors studied, the recently described inter leukins 10 and 13 showed potent inhibition of cell growth, encouraging further investigation on the molecular mechanisms of the observed inh ibition, Apoptosis does not seem to be induced in the two vulvar carci noma cell lines by any of the cytokines studied.