Inhibition of PC cell-derived growth factor (PCDGF, epithelin/granulin precursor) expression by antisense FCDGF cDNA transfection inhibits tumorigenicity of the human breast carcinoma cell line MDA-MB-468

摘要

PC-cell derived growth faCtor (PCDGF) is an 88-kDa growth factor originally purified from the highly tumorigenic teratoma PC cewl line and corresponds to the epithelin/granulin precursor. In teratoma cells, PCDGF expression was shown to be essentiaI for tumorigenicity. We have reported that PCDGF was expressed in estrogen receptor- positive (ER+) human mammary epithelial cells in an estrogen-depen- dent fashion. In this study. we have investigated PCDGF expression in human mammary epithelial cell lines ranging from immortalized nontumorigenic cells to ER+ and ER-- breast carcinoma cells. Northern and Western blot analyses indicated that PCDGF mRNA and protein expression was low in nontumorigenic cells and increased in human breast carcinomas cell lines in a positive correlation with their tumor- igenicity. Treatment of the ER-- MDA-MB-468 cells with anti-PCDGF neutralizing antibody resulted in a dose-dependent inhibition of their proliferation, suggesting that secreted PCDGF acted as an autocrine growth factor for breast carcinoma cells. We then examined the in the and in vivo growth properties of MDA-MB-468 cells, where PCDGF expression had been inhibited by antisense PCDGF cDNA transfection. Inhibition of PCDGF expression resulted in a reduced proliferation rate in vitro and a 60--80/100 reduction in colony forma- tion. Tumor formation in vivo was dramatically inhibited in antisense cells with a 90/100 inhibition of tumor incidence and tumor weight. these results demonstrate the importance of PCDGF overexpression for the proliferation and tumorigenicity of ER-- breast carcinomas and suggest that PCDGF overexpression may play an important role in human breast cancer.