EGF-related peptides are involved in the proliferation and survival of MDA-MB-468 human breast carcinoma cells

A majority of human breast carcinomas co-express the epidermal growth facto r (EGF)-like peptides CRIPTO (CR), amphiregulin (AR) and transforming growt h factor alpha (TGF-alpha). MDA-MB-468 breast carcinoma cells express CR, A R and TGF alpha, while SK-BR-3 cells express CR and TGF-alpha. Anti-sense p hosphorothioate oligodeoxynucleotides (AS S-oligos) directed against either CR or TGF-alpha inhibit the proliferation of both cell lines. A 40-50% gro wth inhibition was observed at a 2-mu M concentration of each AS S-oligo. T reatment with the AR AS S-oligo also resulted in a significant inhibition o f MDA-MB-468 anchorage dependent growth (ADG), No significant growth inhibi tion was observed when MDA-MB-468 or SK-BR-3 cells were treated with a mis- sense S-oligo, The AS S-oligos inhibited the expression of AR, CR or TGF-al pha proteins and mRNAs, as assessed by immuno-cytochemistry and semi-quanti tative RT-PCR. An additive growth-inhibitory effect was observed when MDA-M B-468 cells were treated with a combination of EGF-related AS S-oligos, Ind eed, treatment of MDA-MB-468 cells with a combination of AR, CR and TGF-alp ha AS S-oligos resulted in about 70% growth inhibition at a concentration o f 0.7 mu M each. Finally, treatment of MDA-MB-468 cells with a combination either of the 3 AS S-oligos or of an EGF receptor-blocking antibody (MAb 22 5) and either CR, AR or TGF alpha AS S-oligos resulted in a significant inc rease in DNA fragmentation. Our data suggest that the EGF-related peptides are involved in the proliferation and survival of breast carcinoma cells. ( C) 1999 Wiley-Liss, Inc.