Interleukin 6 acts as a paracrine growth factor in human mammary carcinoma cell lines

Jason J. Chiu, Magdalene K. Sgagias, Kenneth H. Cowan

Research output: Contribution to journalArticlepeer-review

89 Scopus citations


The effect of interleukin 6 (IL-6) on normal and human mammary carcinoma epithelial cells was studied. IL-6 inhibited the growth of estrogen receptor-positive [ER(+)] breast cancer cell lines, which underwent apoptosis with prolonged treatment. In contrast, ER(-) breast cancer cell lines were resistant to IL-6-mediated growth inhibition. By examining the components of the IL-6 receptor (IL-6R) system, we found that ER(+) breast cancer cells expressed predominantly soluble IL-6Rα, whereas the ER(-) breast cancer cells expressed primarily the transmembrane form of the IL-6R, gp130. In addition, detectable levels of IL-6 were secreted into the medium by ER(-) but not ER(+) breast cancer cells. Furthermore, the supernatant obtained from IL-6-secreting, ER(-) cells suppressed the growth of IL-6-sensitive, ER(+) breast cancer cells in a paracrine fashion. Although IL-6 is secreted by ER(-) breast cancer cells, this cytokine does not seem to stimulate the proliferation of these cells in an autocrine fashion. These studies indicate that IL-6 can regulate the growth of normal and transformed human mammary epithelial cells differentially, and that IL-6 secretion by some ER(-) breast cancer cells can function as a paracrine growth factor, suppressing the growth of ER(+) breast cancer cells in vitro.

Original languageEnglish (US)
Pages (from-to)215-221
Number of pages7
JournalClinical Cancer Research
Issue number1
StatePublished - Jan 1996
Externally publishedYes

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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