Epidermal growth factor and amphiregulin up‐regulate matrix metalloproteinase‐9 (MMP‐9) in human breast cancer cells

Abstract

The EGF family of proteins encompasses several polypeptides such as epidermal growth factor (EGF), transforming growth factor alpha (TGFa), amphiregulin (AR) and heregulin (HRG-b1). These polypeptides regulate proliferation in breast cancer cells through interaction with membrane receptors. It has been previously shown that high EGF receptor number correlates with aggressive behavior and increased metastasis in human breast cancer. In the present study, we investigated the association between EGF and EGF-like ligandinduced DNA synthesis and secretion of MMP-9 and MMP-2 in metastatic SKBR-3 and non-metastatic MCF-7 breast cancer cells. Exposure of SKBR-3 cells to EGF or AR induces expression of MMP-9 but has no effect on MMP-2 secretion. In contrast to EGF and AR, HRG had no effect on gelatinase induction. None of the EGF polypeptides had any effect on gelatinase induction in MCF-7 non-metastatic breast cancer cells. While a relatively specific inhibitor of EGF receptor tyrosine kinase, PD 153035, inhibited EGF-, AR-and HRGinduced cell proliferation, it had no effect on MMP-9 induced by EGF and AR. Experimental evidence suggests that signaling mechanisms for cell proliferation and MMP-9 induction are mediated by different pathways down-stream of EGF receptor autophosphorylation or that low levels of EGFinduced signal that escape inhibition are sufficient to induce MMP-9 but unable to support cell proliferation. In addition, our results suggest that EGF and AR may modulate invasion of metastatic breast cancer cells by increasing the expression of MMPs. Int.

Differential regulation of cell proliferation and protease secretion by epidermal growth factor and amphiregulin in tumoral versus normal breast epithelial cells

“…Moreover, the ratio PAi-1/uPA appeared clearly in favour of PAi-1, suggesting that uPA activity might be efficiently neutralized. Recently, studies have demonstrated that EGF and AR were able to induce the expression of matrix metalloproteinases (MPPs) in a variety of tumoral cell lines (Kondapaka et al, 1997;Sundareshan et al, 1999). Although these studies have not established a direct link between the increased production of MMPS and cell invasiveness, we suggest that EGF and AR might modulate invasion of MCF-7 cells by up-regulating the expression of member(s) of MPP family.…”

MAP kinase/estrogen receptor cross-talk enhances estrogen-mediated signaling and tumor growth but does not confer tamoxifen resistance

“…Immunoblots were performed as described previously (Kondapaka et al, 1997) by standard methods on crude protein extracts obtained from 5610 6 cells untreated or treated. Cell extracts containing 50 mg of total protein per sample (determined by using Sigma protein assay) were analysed by SDS ± PAGE using 12% polyacrylamide gels or as indicated.…”

Temporal and quantitative regulation of mitogen-activated protein kinase (MAPK) modulates cell motility and invasion

“…Equal amount of protein from di erent groups were subjected to SDS ± PAGE and transferred to a membrane. Phosphorylated MAPK and total MAPK were assayed as described previously (Kondapaka et al, 1997). In brief the activated proteins were detected by immunoblot analysis with the phospho-MAPK.…”