[The inhibitory effect of antisense interleukin-6 on the growth of human lung carcinoma cells in vivo].

OBJECTIVE

Interleukin-6 (IL-6) has previously been implicated as a potential positive autocrine regulator of a human lung carcinoma cell lince PG. The purpose of the present study is to further evaluate the role of IL-6 in PG cells in vivo.

METHODS

An antisense expression vector for IL-6 was constructed and introduced into PG cells. Antisense mRNA of IL-6 was detected by RNA-RNA dot blotting analysis. The production of bioactive IL-6 was measured by bioassay method. To determine the effect of antisense IL-6 cDNA on tumorigenicity, PG cells were inoculated subcutaneously into nude mice.

RESULTS

Four transfectants, PGTAS1, PGTAS6, PGTAS8, PGTAS9, could express IL-6 antisense mRNA and secret decreased bioactive IL-6. The growth rate of 4 transfectants revealed was reduced in vitro. Comparing with the mice injected with the control PGTneo cells, the latent period of the mice inoculated with PGTAS6, PGTAS8, PGTAS9 cells was significantly increased, and the growth rate of the tumors was obviously decreased. The tumor size was markedly smaller. There was a negative correlation between the growth-inhibiting effect of IL-6 antisense gene and the amount of IL-6 secretion.

CONCLUSION

These results indicate that IL-6 can function as an autocrine stimulator for PG cells in vivo as well as in vitro.